Vạt Da Và Phẫu Thuật Tái Tạo (Flaps and Reconstructive Surgery)

CHAPTER 22 — Lower Extremity Reconstruction
269
A 40-year-old man with a history of a Gustilo IIIB tibia-fibula fracture of the left leg and right leg tibia-fibula fracture as well (Fig.
22.17).
CASE 22.3  Open Tib-Fib Fracture Reconstructed with a Free Iliac Crest Osteocutaneous
Flap and a Free TFL Flap
Figure 22.17  (A) The left tibial and fibular defect in the setting of a clean-contaminated wound after external fixation and multiple debride­
ment surgeries. He is 3 weeks after his injury and undergoing definitive reconstruction in a delayed fashion due to contraindications to
reconstruction from his concomitant injuries earlier in the course of treatment. (B) The unhealthy bone is resected leaving an 8 cm tibial
defect. (C,D) A double flap reconstructive plan is devised. The bone will be reconstructed with an iliac crest osteocutaneous flap supplied
by the deep circumflex iliac artery (DCIA). Additional skin coverage is provided by the second flap using the tensor fascia lata (TFL) flap
supplied by the ascending branch of the lateral circumflex femoral artery. (E) The final inset of the skin paddles completely restores all
soft tissue deficits. (F) Lateral view X-ray at the 12-month postoperative time point shows complete bone union with some early hyper­
trophy. A brace will be worn for 2 years to protect against stress fracture until adequate bony hypertrophy of the single strut reconstruction
occurs.
A
B
C
D
E
F

270
PART 3 — RECONSTRUCTION
A 38-year-old woman with a history of a comminuted distal femur fracture that evolved into an infected non-union with a 5 cm bone
defect (Fig. 22.18).46
CASE 22.4  Open Comminuted Distal Femur Fracture Reconstructed with a Free Double
Barreled Osteocutaneous Fibula Flap
Figure 22.18  (A) X-ray of the initial injury. (B-C) Reconstruction with a double-barrel fibula was carried out. (D) A small skin paddle was
harvested with the bone for monitoring purposes. (E) X-ray at the 4-month postoperative time point; there is evidence of bony healing.
The average time to complete union is 8.5 months.46
A
B
C
D
E

CHAPTER 22 — Lower Extremity Reconstruction
271
Expert Commentary 
Lawrence Colen, MD, FACS
This chapter provides the reader with an excellent bibliography
and a very thoughtful approach to the care of lower extremity
soft tissue and bony defects: an approach that could only be
offered by an experienced reconstructive surgeon. As pointed
out by the authors, outcomes are not measured by the success
or failure of a particular operation but, rather, by the quality of
life that follows, as even a successful operation can fail to
provide a pain-free functional limb. Knowing when and how
to reconstruct, and when to amputate requires the exper-
tise that only very experienced reconstructive surgeons can
provide.
The authors have noted that repair of the acute wound
(related to trauma, oncologic resection, and necrotizing soft
tissue infections) differs from that of the chronic wound (dia-
betic, vascular or lymphatic in origin). For the most part, wounds
in the former group occur in otherwise healthy and relatively
young patients whereas the latter group is composed of older
patients with multiple comorbidities that demand a well thought
out approach that takes into account these comorbidities.
I have a few observations and comments that I hope will provide
the reader with additional valuable information when perform-
ing reconstruction on the lower extremity patient.
The authors advocate the use of CT angiography as a rela-
tively non-invasive way to assess the peripheral circulation prior
to free flap reconstruction. For the past 25 years, we have used
Duplex ultrasound to obtain the same information. In addition
to providing us information about the quality and quantity of
blood flow in our recipient arteries, we can also get detailed
information about the deep and superficial venous system that
will provide outflow for our flaps. This is especially important in
the trauma and vascular disease patient where an unrecognized
deep venous thrombosis may be present.
In the care of groin wounds in the vascular bypass patient,
where exposure of either prosthetic or autogenous bypass graft
material is evident, one should be careful when selecting the
sartorius muscle as a flap option. This muscle obtains its blood
supply from segmental vessels coming from the superficial
femoral artery – an artery that may have been bypassed because
of arterial occlusions. We have had a low threshold for trans-
posing the rectus femoris muscle in such cases.
Though “local” muscle flaps are described as the “flaps of
choice” for upper- and middle-third leg wounds, the experi-
enced microsurgeon would know that in the trauma patient with
open fractures, these muscles (gastrocnemius and soleus) may
be too badly damaged to be used for wound closure, and free
tissue transfer may be the safest option. Assessment of the
“local tissues” should be part of any debridement procedure
that is done prior to definitive closure.
I am pleased, but not surprised that the authors are very
careful about recommending “propeller” flaps for lower extrem-
ity repair. If microsurgeons of the caliber of our authors have
difficulty making these flaps work, we should all take notice.
Finally, I would like to add a word about the diabetic limb, as
my experience with these patients has changed the way I
approach the non-diabetic limb. More than any other anatomic
location, reconstruction of the foot requires both technical
expertise and a thorough understanding of the biomechanics
of ambulation. Our goals in all patients should be a pain-free
foot that conserves the energy of ambulation and withstands
the rigors of weightbearing. I personally do not perform free
flap reconstruction of the forefoot as wound problems in this
location can be managed with transmetatarsal amputation,
leaving the patient with a biomechanically sound foot. Foot
wounds in the neuropathic patient, and in many post-traumatic
patients, are most often related to bony abnormalities and
tendon imbalances. Both of these entities must be addressed
at the time of soft tissue repair, whether local flaps or free flaps
are used. The importance of walking track assessment cannot
be overstated.
Access Figures 22.1–22.4, as well as case
examples 22.1 and 22.2 and tables 22.1–22.4
online at
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CHAPTER 22 — Lower Extremity Reconstruction 271.e1
A 46-year-old man (Fig. 22.15A), with a 5 × 5 cm chronic wound
with desiccated bone exposure upon the mid-leg pre-tibial
surface after an avulsion injury 2 years ago. Tentative skin paddle
marked, based upon the perforators of the posterior tibial artery
that are oriented on an imaginary line from the medial aspect
of the tibial condyle to the medial malleolus (Fig. 22.15B). These
perforators initially emanate from the posterior tibial artery and
septum between the soleus and flexor digitorum longus. Initially
the access incision was on the posterior border of the intended
skin paddle design (Fig. 22.15C,D). However, the approach
found that the dominant cutaneous perforator emanating in
musculocutaneous fashion through the soleus muscle was actu-
ally entering the skin posterior to the access incision. Therefore,
a change in the operative plan was made intraoperatively, allow-
ing the access incision to instead be the anterior border of the
skin paddle. The skin paddle was harvested to 8 × 6 cm with
dissection of the single perforator of 4 cm to the entry point to
the posterior tibial artery. The flap was tunneled subcutaneously
and inset to the pre-tibial defect without any tension, compres-
sion, or torsion on the pedicle (Fig. 22.15E,F).
CASE 22.1  Open Leg wound with Exposed Bone Reconstructed with a Pedicled Posterior
Tibial Artery Perforator Flap
Figure 22.15  (A) A 5 × 5 cm chronic wound with desiccated bone exposure on the mid-leg pre-tibial surface. (B) Tentative skin paddle
(C,D) incision – posterior border of skin paddle approach change the access incision became the anterior border of the skin paddle
(8 × 6 cm with dissection of the single perforator of 4 cm to the entry point to the posterior tibial artery). (E,F) The flap tunneled subcu­
taneously and inset to the pre-tibial defect.
A
B
C
D
E
F

271.e2 PART 3 — RECONSTRUCTION
A 38-year-old man had sustained a burn to the mid- and hindfoot
plantar surfaces 8 years ago that had been reconstructed with a
skin graft. The plantar skin was unstable with frequent trophic
ulcers on the weightbearing hindfoot and skin breakdown on
the arch of the foot (Fig. 22.16).
CASE 22.2  Left Plantar Foot Defect Reconstructed with a Free Instep Flap and a Skin
Graft
Figure 22.16  (A) The previous unstable skin graft was excised; areas of the more chronic wound were sent for frozen and permanent
section biopsy to rule out malignancy. (B) The contralateral foot instep flap was designed for transfer. The skin paddle may be harvested
from approximately the meridian line of the plantar foot to the prominence of the navicular bone. Special care is taken to avoid harvesting
any of the donor site’s weightbearing surfaces of the hindfoot and forefoot. (C) The cutaneous perforators from the medial plantar artery
are visualized. (D) At the entry point to the posterior tibial artery, the bifurcation of the medial and lateral plantar arteries (red markers) is
seen. At this level, the cutaneous nerves (yellow markers) to the flap can be seen to come from the medial and lateral plantar nerves.
(E) The posterior tibial artery bifurcation to the medial and lateral plantar arteries of the recipient foot is isolated. (F) Anastomosis was
performed end-to-end of the donor medial plantar artery, and venae comitans to the recipient medial plantar vessels is performed with
inset of the flap on the weightbearing hindfoot.
A
B
C
D
E
F
D

272
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79. Georgescu AV. Propeller perforator flaps in distal lower leg:
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82. Lin C-H, Mardini S, Wei F-C, et al. Free flap reconstruction of foot
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cases. Plast Reconstr Surg 2006;117:2478–87.
83. Hallock GG. The mangled foot and ankle: soft tissue salvage
techniques. Clin Podiatr Med Surg 2014;31:565–76.
84. Mathes SJ, Nahai F. Reconstructive surgery: principles, anatomy
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85. Mourougayan V. Medial plantar artery (instep flap) flap. Ann
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86. Ducic I, Hung V, Dellon AL. Innervated free flaps for foot recon­
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87. Hallock GG. Medial sural artery perforator free flap: legitimate
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576–81.
89. Haddock NT, Alosh H, Easley ME, et al. Applications of the
medial femoral condyle free flap for foot and ankle reconstruc­
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90. Haddock NT, Wapner K, Levin LS. Vascular bone transfer options
in the foot and ankle: a retrospective review and update on strate­
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91. Firat C, Aytekin AH, Erbatur S. Management of composite tissue
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92. Xipoleas G, Levine E, Silver L, et al. A survey of microvascular
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care. Ann Plast Surg 2008;61:280–4.
93. Rohde C, Howell BW, Buncke GM, et al. A recommended proto­
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132. Igari K, Kudo T, Toyofuku T, et al. Combined arterial reconstruc­
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125. Swiontkowski MF, MacKenzie EJ, Bosse MJ, et al. Factors influenc­
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275
Functional Muscle Transfers
for Various Purposes
Milomir Ninković  |  P. Niclas Broer  |  S. Voigt  |  Marina Ninković
23 
INTRODUCTION
Whereas in the past, reconstructive microsurgery mainly
consisted of defect coverage by free tissue transfer, today this
technique allows a continual integration of improved aes­
thetic appearance and functional reconstruction.
Thus, the main goal of functional reconstructive surgery
is to optimally address both functional and aesthetic require­
ments. Sophistication in surgical techniques has enabled the
surgeon to address a wide variety of individual exigencies
with one or more operations. In this respect, free and local
functional muscle transfer has proven to be a valuable recon­
structive procedure in patients with substantial defects and
loss of function in various locations, including the extremi­
ties, abdominal wall, or facial musculature.1,2 The gracilis,
latissimus dorsi, and gastrocnemius are the muscles most
commonly used for functional muscle transplantation.1–3
In cases of combined tissue deficiency and functional
impairment, where local repair or tendon transfer and/or
nerve grafting are not practicable due to extent of the
trauma, free functional muscle transplantation will be the
treatment of choice. Several previous studies have con­
firmed the applicability of this concept.1–5
As with all tissue transfers, the principle of replacing like
with like while minimizing donor site morbidity should be
adhered to. Specifically, muscle type, blood supply, innerva­
tion, volume, excursion, contractility, and expendability
need to be taken into consideration when choosing a donor
for free microvascular transfer.
Basic functions of skeletal muscles include maintenance
of posture, joint stabilization, and active motion. A wide
variety of muscles are available for functional muscle trans­
fer, each of which has distinctive characteristics regarding
its size, shape, and strength.
Generally, there are two main types of muscles, which
differ in their anatomic structure and mechanism of con­
traction: parallel (strap) and pennate muscles. In parallel
muscles, fascicles are arranged in line with the axis of the
muscle. During contraction, these muscles shorten to about
50% of their original length and diameter increases; they
show moderate strength, but are able to contract over long
distances. Examples include the gracilis, serratus, pecto­ralis,
sartorius muscles, and others. In pennate muscles, fascicles
attach in an oblique angle (pennation angle) in relation to
its tendon. When these muscles contract, the pennation
angle increases. They have different lengths of muscle fibers
originating from the tendinous part of the muscle. Com­
pared with strap muscles, pennate muscle fibers have less
range of excursion and can only shorten by about 25%,
but demonstrate significantly more power on contraction.
Examples include biceps femoris, soleus, gastrocnemius
muscles, and others.
These specific muscle characteristics need to be remem­
bered when choosing a muscle for functional reconstruction.
For instance, if a patient requires a large range of motion,
as in forearm reconstruction, the surgeon should select a
strap muscle. If a patient requires more strength than range
of motion, for example, for reconstruction of a lower extrem­
ity muscle, a pennate muscle should be selected.
Another critical surgical principle in functional muscle
transfer is to restore the resting muscle tension. Efficiency
of a skeletal muscle contraction largely depends on its state
of tension as it is stretched between insertion and origin.
Shortening of muscle fibers results in a functional reduction
of contraction force. Since a muscle shows its maximum
potential for contraction when it is almost fully stretched,
adequate adjustment of tension on inset of the muscle is
important in order to obtain maximum strength. Resting
tension and range of contraction must be marked with a
suture or similar in situ before the muscle is detached
at its origin or insertion.6,7 This resting tension must be
adjusted precisely on muscle inset in order to supply suffi­
cient resting tension, while at the same time providing an
optimal range of motion, depending on the individual func­
tional requirements of the recipient site. Therefore, muscle
selection must be targeted to optimally meet these func­
tional requirements.
The necessity of meticulously precise technique regard­
ing the neurovascular anastomoses cannot be overempha­
sized, since this is the key step to ensure survival of the
muscle. Ischemia time is a critical factor to ensure func­
tional muscle recovery. Revascularization of the transplanted
muscle has to be achieved within a maximal time frame of
3 h. Beyond this time, ischemia negatively affects flap sur­
vival and function.
Nerve coaptation requires viable motor fascicles at the
recipient site to innervate the transferred muscle. As in
vascular anastomosis, meticulous microsurgical nerve coap­
tation is essential. The nerve coaptation site should be
placed as close as possible to the neuromuscular junction
of the transferred muscle, in order to provide a minimal
PART 3  —  RECONSTRUCTION

276
PART 3 — RECONSTRUCTION
FUNCTIONAL LOWER LIP
RECONSTRUCTION UTILIZING THE FREE
INNERVATED GRACILIS MUSCLE FLAP
(CASE 1)
PREOPERATIVE CONSIDERATIONS
The lips are highly visible structures on the face and serve
important and diverse functions, such as articulation, mas­
tication, oral competence, and expression of emotion. The
lips are also particularly expressive facial features and convey
emotional and sexual connotations. After the eyes, the lips
may be the second most important organs of attraction,
infatuation, fascination, and imagination for the opposite
sex. The shape, thickness, formation, composition, and
texture of lips play pivotal roles in the overall beauty of a
human face.10
The principal function of the lips is oral competence,
which contributes to deglutition and word articulation. The
sphincter muscle, the orbicularis oris, provides this compe­
tence, together with a supporting cast of paired elevators
and depressors. The unreplaced loss of a significant segment
of orbicularis muscle precludes competence. Ideally, the
reconstructed lip should be sensate to retain the sphincter
function; to oppose vermilion to vermilion of the upper lip
in a watertight continent seal; and to allow a sufficient
opening for food and dentures; and finally it should have
an acceptable aesthetic appearance. On some occasions,
particularly in subtotal and total lip loss, not all these criteria
can be satisfied completely with conventional reconstructive
techniques. However, one should avoid the postoperative
result of a tight, inverted lower lip that disappears beneath
the curtain of the upper lip when the mouth closes.
The classic guidelines of lower lip reconstruction include
repair utilizing local tissues of similar color and texture, as
well as the concept of entire subunit reconstruction, intro­
duced as a fundamental principle to achieve optimal aes­
thetic results.11 Subdividing the lips into aesthetic subunits
can prove to be very beneficial when planning reconstruc­
tive procedures. The lower lip should be considered a single
aesthetic unit, while the upper lip can be divided into two
lateral, and one median (philtrum) subunit. Lower lip
reconstruction is functionally more important because oral
competence depends greatly on a functional lower lip, with
good muscular tone and adequate height and sensation.
When reconstructing the lips, it is important to save or
restore the muscular modiolus and to preserve the orienta­
tion of this symmetric structure in order to achieve good
functional results, as the modiolus is the site of insertion for
the oral sphincter musculature.
The ultimate reconstructive goal is both aesthetic and
functional, leading to a near normal appearance and func­
tional recovery.
In the literature, several procedures have been reported
for reconstruction of large defects (>75%) of the lips. The
lower lip can be reconstructed using local flaps (e.g., cheek
advancement flaps, rotation or nasolabial, regional pedicled
flaps, and free flaps.10,12–19
In our opinion, local flaps can provide good aesthetic
results, especially in elderly people with skin and tissue
laxity. Regarding the functional results and potential
distance for nerve regeneration and to avoid a long period
of muscle denervation.3,8,9
Precise adjustment of muscle resting tension before and
after muscle transplantation is another key principle in
functional muscle reconstruction. Actin and myosin fila­
ments must be optimally aligned in order to exert maximum
strength. Muscle sarcomeres produce maximum force when
they contract from between 80% and 120% of their resting
length (Fig. 23.1). The patient must be prepped and draped
in a fashion that allows full range of motion of the muscle
to be transferred. Prior to detachment, the muscle is
adjusted to optimal tension within the above-mentioned
range prior to placing the marking sutures. The author
utilizes a technique in which the muscle is segmentally
marked with a Prolene suture every 2 cm for transfer of
shorter muscle portions (i.e., gracilis muscle for lower lip
reconstruction) and 5 cm for transfer of longer muscles
(i.e., latissimus dorsi muscle) prior to detachment. On
transplantation, the muscle is inset accordingly. This guar­
antees optimal force and range of contraction following
reinnervation.
While a large number of muscle transfers have been
described in the literature, in this chapter we will mostly
focus on established flaps for novel functional indications
as originally introduced by Ninković et al.2 As such, harvest
of the flaps will not be elaborated on here, but the focus
will lie on appropriate patient selection, pearls regarding
the inset of the flaps, as well as discussion of expected out­
comes and possible complications.
Specifically, we will describe four novel indications for
functional muscle transfers:
1. Functional lower lip reconstruction utilizing the free
innervated gracilis muscle
2. Functional abdominal wall reconstruction utilizing the
innervated latissimus dorsi muscle
3. Functional bladder detrusor myoplasty utilizing the free
innervated latissimus dorsi muscle (LDDM)
4. Neuromusculotendinous gastrocnemius muscle transfer
for the treatment of drop foot.
Figure 23.1  Force–extension relation of skeletal muscle. Note
maximum force is reached during ideal sarcomere length.
20
40
40
60
Tension
(percent of maximum)
Percentage sarcomere length
80
Decreased
length
Increased
length
No cross
bridges
100
120
140
160
180
200
220
60
80
100

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
277
A full-thickness lower lip resection in a 21-year-old man.
CASE 23.1  Full-Thickness Lower Lip Resection Reconstructed with a Free Functional
Gracilis Muscle, a FAMM Flap, and a Skin Graft
Figure 23.2  Preoperative view of a 21-year-old man affected by
a sclerosing basosquamous cancer of the left lower lip. The exten­
sion of the resection requested by the oncologist, after tumor
biopsy, is marked.
Figure 23.3  Intraoperative view after subtotal full-thickness lower
lip resection.
Figure 23.4  The facial artery musculomucosal (FAMM) flap is dissected based on a superior pedicle.
Continued

278
PART 3 — RECONSTRUCTION
CASE 23.1  Full-Thickness Lower Lip Resection Reconstructed with a Free Functional
Gracilis Muscle, a FAMM Flap, and a Skin Graft—cont’d
A
B
Figure 23.5  The gracilis muscle free flap (9 × 6 cm). (A) Harvested, (B) following nerve coaptation.
Figure 23.6  The functional gracilis muscle after inset.
Figure 23.7  Final intraoperative result after coverage with full-
thickness skin graft.
Figure 23.8  Postoperative view at 1 year, after one additional commissuroplasty. Resting position of the reconstructed lower lip.

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
279
CASE 23.1  Full-Thickness Lower Lip Resection Reconstructed with a Free Functional
Gracilis Muscle, a FAMM Flap, and a Skin Graft—cont’d
Figure 23.9  Animated movement of the lips, showing symmetric voluntary lower lip contraction.
A
B
C
D
E
restoration of sensitivity, some doubts exist.10,14,20 Using local
tissues for reconstruction, the lower lip is usually tight with
a bulky upper lip, and a large amount of healthy tissue in
the nasolabial and chin–labial area has to be sacrificed for
reconstruction.21 At present, there is no universally accepted
gold standard for subtotal or total reconstruction of the
lower lip, especially if adjacent chin tissue is included in the
resection.20
Other techniques, such as the Karapandzic and modified
Gillies’s fan flaps, may preserve orbicularis function and lip
sensation, but they change the position of the oral commis­
sure.22 Jackson recommended this technique especially in
subtotal (up to three-quarters) reconstruction of the lower
lip.10 Microstomia often results, even if significant problems
are rarely reported. Total lower lip reconstruction is also
possible using an extended Karapandzic flap, but with this
procedure microstomia results are even more frequent,
requiring additional Abbé flaps and commissuroplasties.
Considering regional flaps, such as the sternocleidomastoi­
deus or deltopectoral flaps, these flaps appear very volumi­
nous, without capacity to contract, and require a two-stage
procedure.23,24 They cause bulkiness on the neck and an
unpleasant appearance of the donor sites.
Finally, free flaps may provide impressive results in head
and neck reconstruction, especially when used for large
defects. The main advantages of a free flap are that the
residual tissues are well preserved and the surgeon does not
need to be concerned about the total amount of the initial
tissue resection. The flap most often performed for total lip
reconstruction remains the radial forearm flap.13,25,26 Good

280
PART 3 — RECONSTRUCTION
The pedicle is divided after completing the dissection of
the recipient vessels at the neck, usually the facial artery and
vein. The pedicle should be kept long enough to reach the
superior thyroid vessels in the event of very extensive resec­
tion of the perioral tissue. To perform a functional muscle
transfer, care needs to be taken to identify and spare the
ipsilateral marginal branch of the facial nerve during the
resection. This nerve should be left as long as possible, and
the obturator nerve shortened as much as possible, in order
to minimize the length necessary for nerve regrowth and
hence, the time necessary for muscle reinnervation. This
basic principle holds true for all functional muscle flaps
described in this chapter. Additionally, if it is possible, the
mental branch of the trigeminal nerve has to be spared and
prepared at the end to be inserted into the gracilis muscle,
in an attempt to achieve neurotization of this muscle and
recovery of sensation.
The required length of the orbicularis muscle to be
reconstructed is equal to the length of the lip during
maximal stretch, and should be measured prior to resec­
tion. In cases of extensive tumor or vascular malformation
involvement or traumatic muscle loss, one cannot but give
reference to the unaffected contralateral side and use one’s
own judgment. It is important, however, that whatever
needed length determined, is transposed to the gracilis
muscle and the appropriate length and tension marked with
sutures prior to harvesting. For the gracilis muscle, optimal
tension is achieved by placing the leg in a 45° abducted and
45° hip flexed position. Again, this is a technical principle
of resting muscle tension, which should be adhered to in all
cases of functional muscle transfers.
The gracilis muscle flap is then harvested and trimmed
to the required dimensions of width and length under
microscopic magnification on the back-table. In order to
thin and tailor the muscle flap, the perimysium should be
split longitudinally while sparing the neurovascular supply,
which usually runs perpendicular to the muscle fibers. This
also helps to decrease bleeding after muscle reperfusion. In
doing so, one can shape the muscle nicely while sparing
neurovascular structures of the muscle subunits.
Simultaneously, a facial artery musculomucosal (FAMM)
flap is prepared to reconstruct the vermilion and the inner
mucosa of the gracilis flap. Pribaz et al. showed that the
facial artery musculomucosal flap can be inferiorly or supe­
riorly pedicled.34,35 In all our cases, the recipient vessels were
the facial artery and vein, combined with a superiorly ped­
icled facial artery musculomucosal flap. In case one
FAMM flap is not enough for full inner lining reconstruc­
tion, a combination of a superior and inferior pedicled
facial artery musculomucosal flap can be utilized from both
sides for appropriate vermilion reconstruction. If the
FAMM flap is not usable due to defect dimensions following
radical resection, a submental pedicled flap can be used as
an alternative for inner lining. At the final stage of the pro­
cedure, the gracilis muscle is covered with unmeshed split-
thickness or full-thickness skin from an area with optimal
color match for the lip, such as the scalp or the supracla­
vicular region.
The gracilis flap is inset using 2-0 Vicryl sutures, taking
into account the aforementioned muscle resting tension
length. The muscle edges should be sutured to solid struc­
tures, such as the remaining orbicularis oris or buccinator
aesthetic and functional results have been reported using
this flap. However, the radial forearm flap does not have its
own motility, and the color and texture match is not perfect.
In an effort to improve motility and symmetry, different
technical solutions such as using palmaris longus tendon
and looping it around the modiolus have been attempted.26,27
However, even these refinements are unable to provide
spontaneous symmetrical lower lip movement. Finally,
donor site morbidity is not inconsiderable. Given the first
author’s experience in functional muscle transfer, we con­
sidered an innervated gracilis muscle as the ideal flap for
lip reconstruction.2,28–30
In the literature, the gracilis muscle has been reported in
reconstructive surgery for the repair of different types of
defects: facial palsy, total tongue reconstruction, muscle
replacement in the upper limb, and several soft tissue
repairs.31 The presented approach is the first on subtotal
and total reconstruction of the lips using a gracilis muscle.
The combination of this flap with the Pribaz facial artery
musculomucosal flap and sensitive neurotization, is a new
concept.
In the case of subtotal resection of the lip, our technique
allows maintaining the symmetry of the mouth, avoiding
distortion of the residual commissure and sparing all facial
tissues around the lip defect. This characteristic is of advan­
tage when a part of the cheek also has to be removed during
resection of a larger tumor; in fact, it is not advisable to
use cheek advancement flaps in such a case. In total lip
reconstruction, the gracilis muscle can restore the oral
sphincter completely, with symmetry of the mouth and
normal opening.
The use of a facial artery musculomucosal flap was used
to reconstruct the inner surface of the gracilis muscle and
to achieve a natural looking vermilion, given appropriate
amounts of available mucosa and the good length and
mobility of its pedicle; it is an axial flap, consisting of
mucosa, submucosa, a small amount of buccinator muscle,
the deeper plane of the orbicularis oris muscle, and the
facial artery and its venous plexus.32 The facial artery mus­
culomucosal flap has the advantage of being a single-stage
procedure, as compared with tongue flaps and cross-lip
flaps, which require secondary division.33
We have thus employed the free innervated gracilis flap
when faced with extensive soft tissue defects of the lips.11
INDICATIONS
The appropriate patient should, in case of malignancy, have
undergone staging as well as a pathologically confirmed R0
resection prior to any reconstructive effort. In suitable
patients, tumor resection, trauma, or congenital vascular
malformations must affect full-thickness tissue of at least
75% of the lower lip.
TECHNIQUE
In cases of non-malignant lesions, a second team harvests a
gracilis muscle free flap in standard fashion simultaneously
during resection of the lip lesion. The average vascular
pedicle length of the gracilis is approximately 6 cm, the
branch of the obturator nerve to the muscle is usually at
least of equal length.

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
281
articulation, mouth opening, or eating. Oral continence was
near perfect, without any air leakage during puffing, and
the oral sphincter function had been completely restored
in all patients. Two patients among the 10 are even able to
whistle.
Motoric reinnervation of the muscle flap can be expected
to occur at approximately 1 mm/day and can therefore
usually be expected around 3–6 months postoperatively. All
our patients showed full reinnervation at 1-year follow-up,
as evidenced by regain of motion including oral compe­
tence, speech, and puckering of the lips.
While requiring up to 1 year, sensation was ultimately
regained in all cases, as confirmed with Semmes–Weinstein
monofilament tests. Patients should be counseled that sec­
ondary surgeries (debulking, scar corrections, gracilis mus­
cle reinsertion, commissure corrections, etc.) may become
necessary in approximately 50% of cases. These procedures
can be carried out under local anesthesia in an outpatient
setting. In our series, both surgeons and patients were ulti­
mately satisfied with the functional and aesthetic results.
DISCUSSION
Luce observed, in 1995,14 that the reconstructed lower lip
often resulted in an immobile, insensate block of tissue that,
in the best of circumstances, serves as a dam rather than an
effective and dynamic structure. To effectively reconstruct
the lower lip, one must provide not only skin and mucosa,
but also a functioning mimetic muscle.
In our opinion, the functional gracilis fulfills all these
requirements; it allows for near normal motion in all por­
tions of the reconstructed lips. The new commissure is
symmetric and moves simultaneously with the residual
commissure due to the innervation by the facial nerve. Fur­
thermore, all our patients regained sensitivity of the recon­
structed lips. Regarding the recovered lip sensation, we
cannot be sure that it is a consequence of the neurotization
of the gracilis via the stump of the mental nerve, or if it is
caused by using the facial artery musculomucosal flap; prob­
ably both play a role for recovery of sensitivity. Neurotization
has been well described experimentally and clinically for
motor nerves, but we are not aware of any publications on
the neurotization of sensitive nerves. The regaining of sen­
sation in the case of a flap transposed into the oral cavity
has already been studied; the most probable explanation
considers the large area dedicated to mouth sensitivity in
the brain homunculus. There are also many sensitive recep­
tors in the mouth mucosa, which may promote migration
of the sensitive fibers into the flap.11
The goal of a reconstructive procedure should be an
optimal functional and aesthetic result, with minimal
donor site morbidity. According to the reconstructive
requirements of lower lip reconstruction, local flaps seem to
be the best option in elderly patients with limited size full-
thickness defects. However, extensive local flaps may be
unsuitable when a total lower lip resection is performed,
especially in young patients who do not have enough laxity
of tissue and who could be discouraged by multiple perioral
scars. We believe that our technique using an innervated
gracilis free flap, combined with a superior pedicled facial
artery musculomucosal flap and skin grafting, allows for very
good functional and aesthetic reconstruction of the lower
muscle. In cases when the oral commissure is involved, the
gracilis has to be split, sutured to the residual opposite orbi­
cularis muscle, and then passed through and looped around
the residual commissural fibers at the level of the original
commissure in order to reconstruct a new oral sphincter.
The vascular pedicle of the flap is anastomosed to the
recipient vessels, subsequently the marginal branch of the
facial nerve is coapted to the obturator and finally to
the mental nerve to restore sensation.
POSTOPERATIVE CONSIDERATIONS
Patients should be anticoagulated according to standard
protocol (low-molecular heparin) and wear compression
stockings at all times until full ambulation. No specific anti­
coagulation is indicated with respect to the microvascular
free tissue transfer. The donor site is closed with a Jackson-
Pratt drain in place, which can be removed once output is
less than 30 cc/day.
The patients are instructed to minimize movement of the
affected area by means of speech or food intake for 3–5 days.
After take of the skin graft is confirmed, approximately 1
week after surgery, motion can be liberated and a simple
chin strap compressive dressing with additional support to
the lower face is applied. This chin strap is worn for 24 h
until muscle swelling has completely diminished. The
purpose of this suspension is to avoid an inverted lip defor­
mity. We generally suggest the patient continues to wear the
suspension garment whenever possible but at least during
the night, until functional muscle recovery. The rehabilita­
tion program is started within 3 weeks of the operation to
reestablish voluntary active labial movement. An electro­
myographic study is performed every 3 months during the
first year after surgery, to evaluate recovery of motor inner­
vation, in addition to the scheduled physical examination
of the patients. The sensory examination includes a touch-
pressure sensation test using the Semmes–Weinstein mono­
filament test; a hot-and-cold discrimination test; and a static
2-point discrimination test.
COMPLICATIONS
Besides common surgical complications (bleeding, infec­
tion, dehiscence, hematoma/seroma formation), complica­
tions specifically related to this operation may include oral
incontinence with subsequent development of drooling;
persistent edema of the flap; poor reinnervation with insuf­
ficient regain of motion and/or sensation; contour irregu­
larities; poor skin color match; poor speech; and partial or
full flap loss.
OUTCOMES
To date we have applied the technique in a total of 10
patients.
There were no partial or full flap losses, but partial loss
of skin grafts occurred in two patients, requiring secondary
skin grafting. Most patients are expected to have a period
of 1–2 weeks of drooling during the time of maximal tissue
swelling. However, none of our patients suffered persistent
drooling in the long-term follow-up. Presently, all our
patients show no drooling or problems with word

282
PART 3 — RECONSTRUCTION
Oncologic resections require a sequenced approach with
primary radical resection and temporary defect coverage,
followed by definite reconstruction. Infected wounds sec­
ondary to trauma are usually not amenable to primary clo­
sure, and must be meticulously debrided, and negative
pressure wound therapy and appropriate systemic antibiotic
therapy according to a resistogram should be applied. Once
the infection is eradicated, reconstruction can be
performed.
Since reinnervation of the latissimus dorsi muscle requires
several months, initial stabilization must be ensured by uti­
lization of autologous tissue or synthetic mesh.
In case of a staged procedure, primary closure can be
achieved with a skin graft. During definitive reconstruction,
the stable skin graft can be dermabraded and subsequently
covered by the latissimus dorsi free flap. The maintained
dermal skin layer provides additional stability, eliminating
the need of prosthetic mesh for internal stabilization. In a
single-step procedure, the latissimus dorsi must be placed
on a synthetic internal support layer (i.e., Prolene or Vicryl
mesh) to provide initial stability.
The latissimus dorsi muscle is harvested in a standard
fashion. Depending on the required recipient site dimen­
sions, the flap can be harvested as a pure muscle or myocu­
taneous flap. Incorporating a skin island for soft tissue
coverage allows significant improvement of aesthetic appear­
ance. The thoracodorsal vessels of the flap are usually
coapted to the superior or inferior epigastric vessels and
their venae comitantes. A 5–15 cm long pedicle can usually
be obtained based on the subscapular system. The thora­
codorsal nerve innervating the latissimus muscle is of at
least equal length. The nerve is coapted to one or two intact
intercostal nerves supplying the rectus abdominis muscle.
Identification and tension-free coaptation of the thora­
codorsal nerve to the intercostal recipient motor branch is
crucial to ensure restoration of muscle innervation and con­
traction. Depending on the defect size, the muscle must be
safely attached to mechanically stable structures usually
comprised of the superior iliac spine, the pubic symphysis,
and the lower boarder of the ribs.
POSTOPERATIVE CONSIDERATIONS
The free flap should be monitored according to protocol
during the first postoperative days. The patient should
wear a supportive abdominal binder once ambulation is
resumed. Ideally, this binder should be worn continuously
until full muscle reinnervation has occurred (6–9 months).
Following the initial wound healing phase, the patient must
undergo intensive physiotherapeutic mobilization to quickly
regain function of the transplanted muscle. Regular electro­
myography (EMG) and measurement of nerve conduction
velocity provides important information about muscular
reinnervation and resumption of muscle function. Strenu­
ous exercise and heavy lifting of more than 10–15 pounds
should be avoided during this time period.
COMPLICATIONS
Complications include general surgical complications
(bleeding, infection, dehiscence, hematoma/seroma forma­
tion). Complications specifically related to this operation
may include inadequate defect coverage and functional
lip, restoring dynamic, spontaneous, and voluntarily con­
trolled lower lip movement and good appearance, achieved
with just one surgical procedure and minimal donor site
morbidity.
FUNCTIONAL ABDOMINAL WALL
RECONSTRUCTION (CASE 2 and 3)
Full-thickness abdominal wall defects constitute a particular
challenge in reconstructive surgery. A distinction must be
made between partial abdominal wall weakness, limited
to the fascia but with sufficient soft tissue coverage, and
full-thickness defects, requiring restoration of functional
strength and stabilization, as well as adequate soft tissue
coverage.2 Established methods to stabilize abdominal wall
defects include utilization of artificial mesh and acellular
dermal matrices, component separation, fascia lata allografts,
as well as pedicled and free flaps.36–40 While fascial defects
in cases of hernias can in general be adequately treated
using synthetic mesh or other matrices, full-thickness defects
including fascia, muscle, and skin require more complex
treatment. An ideal reconstruction must provide functional
strength and stabilization, while at the same time leading to
an acceptable aesthetic appearance. Current options for
full-thickness abdominal wall reconstruction include local
myo- and myocutaneous flaps from the adjacent abdomen,
pedicled and free fascia lata flaps, rectus femoris, and sar­
torius flaps.17,41–44
Here, we describe utilizing the free latissimus dorsi flap
as a means of restoring both functional stability as well as
aesthetic appearance.
PREOPERATIVE CONSIDERATIONS
The abdominal wall consists of multiple, partially overlap­
ping layers. These are (from superficial to deep) skin; sub­
cutaneous tissue; Scarpa’s fascia; rectus abdominis muscle;
external oblique muscle; internal oblique muscle; transverse
abdominal muscle; pyramidalis muscle; fascia transversalis;
and finally the peritoneum, which separates the intra-
abdominal cavity from the overlying structures. Muscles of
the anterolateral abdominal wall increase the stability of the
lumbar region of the vertebral column by tensing the tho­
racolumbar fascia and by increasing intra-abdominal pres­
sure.45 It is important to note that muscles not only
participate in the movement itself, but also in its control and
in maintaining spinal stability.46 Thus, instability of the
abdominal wall may result in distorted posture, functional
instability of the vertebral spine, and potentially premature
joint degeneration.
INDICATIONS
Instability and hernia formation of the abdominal wall may
result from trauma, oncologic tumor resection, extensive
intra-abdominal surgery, severe local infection, or various
other operative complications.
TECHNIQUE
Depending on the indication the procedure can be per­
formed in a single- or multiple-step procedure.

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
283
A 41-year-old woman with a full-thickness abdominal wall defect
measuring 25 × 14 cm, 12 years after radical resection of a
dermatofibrosarcoma protuberans and reconstruction with skin
graft.
CASE 23.2  Full-Thickness Abdominal Wall Defect Reconstructed with a Free Innervated
Latissimus Dorsi Myocutaneous Flap
Figure 23.10  A 41-year-old patient presenting with a full-
thickness abdominal wall defect measuring 25 × 14 cm and signifi­
cant infraumbilical hernia, 12 years after primary tumor resection.
Figure 23.11  Intraoperative view showing a very stable, fascia-
like layer after deep dermabrasion of the skin graft. Note the con­
tralateral lower intercostal nerve dissected (arrow).
Figure 23.12  Nerve coaptation of the thoracodorsal nerve of the
free latissimus flap to a lower branch of the intercostal nerves sup­
plying the rectus abdominis muscle.
Figure 23.13  Patient is shown 23 months after reconstruction with innervated latissimus dorsi flap in (A) anterior and (B) lateral view.
Note synergistic function of the transferred latissimus dorsi and rectus muscles with near perfect symmetry and contour without bulging.
A
B

284
PART 3 — RECONSTRUCTION
A 28-year-old patient with a full-thickness, right-sided abdominal wall defect secondary to motor vehicle trauma.
CASE 23.3  Full-Thickness, Right-Sided Abdominal Wall Defect Reconstructed with a Free
Innervated Latissimus Dorsi Myocutaneous Flap
Figure 23.16  Intraoperative view after deep dermabrasion of
meshed skin showing a stable dermal layer.
Figure 23.14  Intraoperative view after tissue debridement and
primary coverage with meshed skin grafts.
Figure 23.15  A 1-year postoperative view showing meshed skin
graft firmly adherent to bowel.
Figure 23.17  The harvested myocutaneous latissimus flap prior
to inset.
Figure 23.18  Final result 3 years after reconstruction with innervated latissimus dorsi
flap (anterior view).

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
285
CASE 23.3  Full-Thickness, Right-Sided Abdominal Wall Defect Reconstructed with a Free
Innervated Latissimus Dorsi Myocutaneous Flap—cont’d
Figure 23.19  Functional result 3-year postoperative with patient
performing sit-up. Note synergistic function of the transferred latis­
simus dorsi and rectus muscles with near perfect symmetry and
contour without bulging.
Figure 23.20  Abdominal wall strength testing showed range of
motion and strength within normal range.
stability due to inadequate donor muscle dimensions or
poor quality of surrounding tissues. Failure of neuromuscu­
lar reinnervation due to imprecise neural coaptation of the
thoracodorsal to the intercostal nerves, thrombosis and
bleeding at the site of vascular microsurgical anastomosis,
persistent seroma formation, bulging, partial or full flap
loss, and recurrent hernia formation may occur.
OUTCOMES
Thus far, we have employed the described technique in a
total of 12 patients. In two early cases, patients displayed
significant abdominal wall bulging and hernia formation
due to lack of internal soft tissue support. The author sub­
sequently modified the technique; in case of a one-step
procedure, stability is achieved by placement of a non-
resorbable mesh prior to flap inset. If a two-stage procedure
is required, initial treatment usually entails placement of
a split-thickness skin graft on the defect site. Prior to
functional reconstruction, the skin graft is meticulously
de-epithelialized by means of the VersajetTM device. The
de-epithelialized fibrotic tissue provides sufficient structural
support to prevent bulging and hernia formation. There
were no free flap failures; three patients developed donor
site seroma. One young patient died 8 months following
functional abdominal wall reconstruction following bowel
transplantation due to immunologic response. Another
patient died 2 months postoperatively following sarcoma
resection due to systemic metastasis.
FUNCTIONAL DETRUSOR MYOPLASTY
UTILIZING THE LATISSIMUS DORSI
MUSCLE FLAP (CASE 4)
INTRODUCTION
Patients with bladder acontractility caused by lower motor
neuron lesions are generally dependent on lifelong clean
intermittent catheterization (CIC), with all of its associated
risks. At present, little can be gained from treating a bladder,
which is flaccid as a result of lower motor neuropathy or
impaired detrusor contractility, by electrical stimulation of
the spinal cord, sacral roots, or the detrusor muscle itself.47,48
Based on results from studies with animals, we developed
a surgical technique involving neurovascular free latissimus
dorsi transfer to the pelvis in order to restore voluntary
emptying of the bladder. This functional transfer is one of
the few options to restore voiding in patients with long-
standing bladder acontractility.
A poor detrusor contractility and related impaired
bladder emptying is a debilitating and irreversible disorder,
presenting a major medical and social problem.49 Such
bladder acontractility may be caused by damage to the
detrusor muscle itself, its autonomic nerve supply, or the
spinal micturition center. Possible etiologies include con­
genital anomalies (e.g., myelomeningocele, myelodyspla­
sia), acquired infections, inflammatory or autoimmune
diseases, chronic overdistension of the bladder due to

286
PART 3 — RECONSTRUCTION
A 45-year-old patient presenting with cauda equina syndrome
and associated acontractile bladder after a fall from a height.
The outlined indications were met and the patient underwent a
detrusor myoplasty.
CASE 23.4  Cauda Equina Syndrome and Associated Acontractile Bladder Reconstructed
with a Free Innervated Latissimus Dorsi Muscle Flap
Figure 23.21  Muscle resting tension is marked every 5–10 cm
prior to dissection of the latissimus dorsi muscle.
Figure 23.22  Intraoperative view of the latissimus dorsi muscle
following dissection. Note that after the muscle has been dissected
resting tension cannot be adequately determined.
Figure 23.23  Harvested LDM flap. Note the thoracodorsal vessels
(white arrow) and full preserved length of the thoracodorsal nerve
(black arrow).
Figure 23.24  Flap after inset and neurovascular anastomosis.
*, Peritoneum; #, bladder; L, latissimus flap; R, rectus muscle.

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
287
CASE 23.4  Cauda Equina Syndrome and Associated Acontractile Bladder Reconstructed
with a Free Innervated Latissimus Dorsi Muscle Flap—cont’d
Figure 23.25  Schematic illustration of functional latissimus dorsi
flap inset over passively filled bladder.
Latissimus dorsi
Bladder
Prostate
Urethra
Ureters
Figure 23.26  Schematic illustration of final functional latissimus
dorsi inset with vessel anastomosis and nerve coaptation.
Latissimus dorsi
Urethra
Ureters
subvesical outlet obstruction, and central or peripheral
nerve injuries secondary to trauma or degenerative diseases.
The hypo- or areflexic bladder characteristically results in
urinary retention and overflow incontinence, which may be
associated with urinary tract infections, stone formation,
and vesicoureteral reflux. Left untreated, this condition
inevitably leads to impairment of the upper and lower
urinary tract.
The main goals in treating patients with neurogenic
bladder dysfunction are preservation of upper urinary tract
integrity, insurance of adequate continence, as well as mini­
mizing stone formation and urinary tract infections. All
these therapeutic goals aim at improving the patient’s
quality of life and prolong overall life expectancy.
Until now, the gold standard in treating neurogenic
bladder dysfunction has been lifelong clean intermittent
catheterization, which has reduced renal-related mortality
in the last four decades, but is also associated with serious
adverse effects. Urinary tract infections are the most fre­
quent complication in patients performing intermittent
catheterization (12–88% of all patients).48 Further serious
complications of CIC may be development of epididymitis,
epididymo-orchitis, urethral trauma and consequent stric­
ture formation, bladder injury, and urolithiasis, which may
ultimately all lead to deteriorating renal function.47,50 In
addition, the socioeconomic and psychological burdens
of lifelong intermittent catheterization should not be
underestimated.48,51,52
The disadvantages of CIC emphasize the importance of
effective alternative treatment options for acontractile
bladder dysfunctions.
One approach is the so-called “sacral neuromodulation,”
which supports voluntary bladder emptying by electrical
stimulation,53,54 but requires an intact spinal cord, micturi­
tion center, and spinal roots.9 If these prerequisites are not
fulfilled, voluntary micturition can only be achieved by a
functional muscle transfer.
The free neurovascular latissimus dorsi muscle is a good
option for such a transfer, as it provides a suitable neurovas­
cular pedicle, as well as appropriate muscle size and configu­
ration of muscle fibers.28,30 In this procedure, the latissimus
dorsi muscle is partially wrapped and secured around the
acontractile bladder, and the thoracodorsal nerve is coap­
tated to the lowest rectus muscle supplying branch of the

288
PART 3 — RECONSTRUCTION
TECHNIQUE
The patient is placed in a supine position with the respective
shoulder elevated and the arm placed overhead to enable
synchronous work at the nondominant latissimus dorsi
muscle (LDM) and the bladder by two surgical teams (urol­
ogists and plastic surgeons). The entire arm and shoulder
are prepped and draped in a fashion that allows full range
of motion in order to determine optimal resting tension
prior to marking the muscle. For the latissimus dorsi, this is
achieved by placing the arm in 90° shoulder abduction and
20–30% anteversion. An axillary Z-incision offers direct
access to the anterior border of the LDM and facilitates dis­
section of the thoracodorsal neurovascular bundle as proxi­
mal as possible. Again, it is mandatory to mark the resting
muscle tension before separating the muscle at its origin
and insertion. Two marking sutures at defined distances are
placed on the muscle, and, when insetting the flap, every
effort is made to re-extend the muscle to its original length
during its fixation over the filled bladder in the pelvis.
The LDM is completely elevated except for the neurovas­
cular bundle, which is not transected until the recipient
vessels have been prepared for microanastomosis.
A double-lumen catheter must be placed in all cases to
allow retrograde filling of the bladder during the operation,
which helps to determine adequate stretch and tension of
the wrapped latissimus muscle.
For bladder exposure, a Pfannenstiel incision is made
and the bladder is freed down to its trigone. In cases of a
bladder with small capacity, an auto-augmentation can be
performed by excision or incision of the diseased detrusor.
Subsequently, the inner surfaces of both ischial bones and
insertions of the sacrospinal ligaments are identified. In
male patients, after preparation of Denonvilliers’ fascia, a
polyglactin mesh is placed at the posterior bladder wall and
secured with single sutures at the pubic arc to provide a
counter bearing for the LDM; in women the uterus takes
over this function. Prior to inset, the holding sutures for the
fixation of the LDM in the pelvis are all placed in a circum­
ferential fashion to the aforementioned fascial and ligamen­
tous structures.
After identifying the deep inferior epigastric vessels, the
thoracodorsal vessels and nerve are divided, the LDM is
wrapped in a cool moist towel, and transferred to the recipi­
ent site, and microsurgical vascular anastomosis is per­
formed immediately to keep the ischemia time as short as
possible (no more than 30 min). Donor site closure is per­
formed simultaneously using several interrupted absorbable
sutures between the skin flap and the thoracic wall to reduce
the large wound cavity and consequently the risk of postop­
erative seroma formation. The anastomosis should be per­
formed with the LDM upside down as the flap will be
positioned accordingly in the pelvis.
Following this, the flap is secured to the pelvis by means
of the pre-placed sutures. When doing so, a slightly spiral
configuration of the LDM is optimal, taking the original
muscle resting tension into consideration.
Finally, the thoracodorsal nerve is coapted to the lowest
branches of the intercostal nerves; nerve stimulation is
crucial to identify a potent donor nerve. Nerve selection
and repair are the most critical parts of this procedure, as
meticulous nerve coaptation is essential for reinnervation.
intercostal nerve. Following the reinnervation of the latis­
simus, voluntary contraction of the rectus abdominis results
in a simultaneous contraction of the transferred latissimus
muscle, which leads to emptying of the bladder.29
PREOPERATIVE CONSIDERATIONS
As mentioned earlier, bladder acontractility caused by an
upper motor neuron lesion (i.e., multiple sclerosis, apoplec­
tic stroke, spinal trauma above the 12th thoracic vertebra),
is usually not treatable by the described functional muscle
transfer. Potential candidates for the latissimus dorsi detru­
sor myoplasty (LDDM) are only patients with acontractility
caused by lower motor neuron lesion. This may be due to
spinal trauma below Th12, tethered cord syndrome, lumbar
hernia prolapse, megacystis/bladder outlet obstruction,
sacral myelomeningoceles, idiopathic causes, and chronic
retention after hysterectomy.
Considering the complexity of the procedure, life expec­
tancy at the time of operation should be more than 10 years,
and there should have been no improvement of bladder
function for at least 1 year following the initial inciting
event. Patients should have proven to be able to safely
perform clean intermittent catheterization for at least 1
year. Furthermore, there should be no signs of infravesical
obstruction at urethrocystoscopy.55
Routine preoperative evaluation includes video-
urodynamic studies, diagnostic urethrocystoscopy, and ex­
cretory urography. In addition, electromyography of the
lower portion of the rectus abdominis muscle should be
performed to confirm an intact 12th intercostal motor
nerve for the neural coaptation. In patients with idiopathic
cause of the disease, a neurophysiological assessment of the
sacral district including magnetic resonance imaging or
computerized tomography is recommended to exclude an
upper motor neuron lesion.
Targeted preoperative diagnostics are also essential to
identify those patients who are eligible for a detrusor myo­
plasty versus those who could benefit from sacral neuro­
modulation. Urodynamics are essential to evaluate suspected
acontractility. In cases of equivocal urodynamic findings,
sacral neuromodulation should be applied to rule out the
presence of bladder hypocontractility rather than acontrac­
tility. Direct electrostimulation of the sacral nerves may then
help to identify those patients with hypocontractility who
might be candidates for implantation of a permanent device
for sacral neuromodulation (Box 23.1).55
Box 23.1  Indications for the Latissimus
Dorsi Detrusor Myoplasty
• Bladder acontractility without upper motor neuron lesion
• No indication for neuromodulation
• Life expectancy >10 years
• No improvement of bladder dysfunction >1 year
• Patients should handle clean intermittent catheterization
>1 year
• No infravesical obstruction present
• Intact 12th intercostal motor nerve

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
289
No chronic pain at the donor site or vesicoureteral reflux
was observed in any patient of this series. The procedure
was associated with major complications (deep vein throm­
bosis; pulmonary embolism; pelvic abscess requiring tempo­
rary drainage; compartment syndrome of the nonoperated
shoulder due to pressure from positioning; wound healing
complications; and persistent seroma of the donor site
requiring surgical drainage). All patients who experienced
a major complication recovered completely. No free flap
failure was encountered intra- or postoperatively. The mean
operating time was 536 ± 22 min and the median length of
hospital stay was 13 days (range 7–32 days).55
Instead of the latissimus dorsi muscle (LDM), the rectus
abdominis muscle has also been proposed as a potentially
appropriate muscle for functional transfer to restore volun­
tary voiding; however, overall results have been poor.
In contrast, the clinical results of the LDDM demonstrate
that this procedure is reliable for restoring bladder func­
tion.29,30,55,56 This success is, among other factors, due to the
characteristics of the donor muscle. The LDM has a suffi­
cient cross-section and mass to exert significant force, and,
due to the anatomic arrangement of the muscle fibers with
a strap muscle configuration as opposed to that of a pennate
configuration, a suitable fiber length to provide good excur­
sion. In addition, the reliable neurovascular anatomy and
its large surface make the LDM predestined for this applica­
tion. Advocates of the rectus abdominis myoplasty have criti­
cally appraised that the use of the LDM comes along with
significant donor site morbidity, pointing out that paraple­
gic patients rely on their upper extremities and torso
strength for mobility.57 However, it should be noted that the
morbidity of the LDM donor site is well analyzed in large
series, and considered to be low overall. In the authors’
opinion, it stands in no proportion to the benefit of the
regained ability to void voluntary.58,59 Alternate muscle flaps
of the lower extremity, which conceivably would be more
favorable in cases of paraplegic patients, usually do not meet
the above-mentioned muscle requirements.
In summary, the free functional LDDM transfer is a cura­
tive treatment option for the select group of patients, who
would otherwise require lifelong clean intermittent cathe­
terization with its inherent disadvantages. Eliminating the
need for self-catheterization leads to growing self-confidence,
facilitates daily and occupational activities, and may improve
quality of life significantly.
NEUROMUSCULOTENDINOUS TRANSFER
FOR THE TREATMENT OF DROP FOOT
(CASE 5)
PREOPERATIVE CONSIDERATIONS
The deep peroneal nerve innervates the muscles of the
anterior compartment of the leg, which are tibialis anterior,
extensor hallucis longus, extensor digitorum longus, and
the fibularis (peroneus) tertius. Together, these muscles
are responsible for dorsiflexion of the foot and extension
of the toes. Additionally, the deep peroneal nerve innervates
the intrinsic muscles of the foot including the extensor
digitorum brevis and the extensor hallucis brevis. Injury or
damage to the deep peroneal nerve or the anterior muscle
As mentioned above, the nerve repair should be placed as
close as possible to the neuromuscular junction (i.e., the
intercostal nerve should be kept as long as possible, and the
thoracodorsal nerve should be shortened as much as pos­
sible), to require a minimal distance for nerve regeneration
to take place and to avoid long periods of muscle denerva­
tion (see Pearls and Pitfalls).
Pearls
• A generous Z-incision in the axilla enables the
essential long dissection of the neurovascular pedicle.
• The resting muscle tension has to be marked before
separating the L DM; the transferred muscle must be
re-extended according to these marks.
• Motor branches of the intercostal nerves should be
identified by electrostimulation.
Pitfalls
• The diameter of the thoracodorsal vein and the
recipient vein (deep inferior epigastric vein) may
differ, which can impede the venous anastomosis.
• Inadequate selection of the recipient nerve and
improper nerve coaptation (e.g., under tension) can
compromise the whole reconstruction.
POSTOPERATIVE CONSIDERATIONS
Muscle flap vascularization has to be confirmed by Doppler
ultrasonography regularly in the first postoperative days,
and at 3-month intervals during the first year. In our experi­
ence, placement of a Vicox-O2 measuring probe has proven
to be a valuable tool when monitoring the free flap in the
immediate postoperative period.
The bladder has to be drained initially with an indwelling
transurethral catheter for 4 weeks, and subsequently, with
clean intermittent catheterization for a total of 12 weeks.
After this period, the patients are instructed to void under
physiotherapeutic guidance by voluntarily contracting the
lower abdominal muscles. Post-void residual urine volumes
have to be measured by self-catheterization, and catheteriza­
tion intervals are gradually increased accordingly. Video-
urodynamic evaluations should be performed at 6 months
postoperatively, and yearly thereafter.29,30,55
OUTCOMES
Current long-term results confirm that the LDDM is an
effective alternative to clean intermittent catheterization in
a select group of patients. In a multicenter investigation,
median follow-up of 24 patients was 46 months (range 8–89
months). Of the 24 patients, 17 (71%) regained complete
spontaneous voiding, with a mean post-void residual urine
volume of 25 cc (range 0–100 cc). In three patients (13%),
the frequency of clean intermittent catheterization was
reduced to 2–4 times daily, with a mean post-void residual
urine volume of 200 mL (range 150–250 mL). Recurrent
urinary tract infections ceased in 21 of 23 patients (91%).
Four patients (17%) required clean intermittent catheter­
ization with the same frequency as before the procedure.

290
PART 3 — RECONSTRUCTION
A 28-year-old patient presenting with drop foot following compartment syndrome with complete destruction of the anterior muscle
compartment.
CASE 23.5  Drop Foot Reconstructed with a Pedicled Innervated Gastrocnemius Muscle
Figure 23.27  Dissection of vital the deep peroneal nerve.
Figure 23.28  Intraoperative view after dissection of the gastroc­
nemius muscle and its neurovascular pedicle.
Figure 23.29  Transposition of the gastrocnemius muscle.
Figure 23.30  Intraoperative view prior to suturing the gastrocne­
mius (GM) tendon to the tendons of the TA, EDC, and EHL tendons.

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
291
CASE 23.5  Drop Foot Reconstructed with a Pedicled Innervated Gastrocnemius
Muscle—cont’d
Figure 23.31  (A) Postoperative view with full range of voluntary dorsiflexion in the ankle joint with an excellent result. (B) Postoperative
view with full range of voluntary plantar flexion with good functional outcome.
A
B
compartment results in functional impairment of dorsiflex­
ion of the foot, clinically described as “drop foot syndrome.”
It is characterized by a steppage gait abnormality, in which
the ankle and foot remain in plantar flexion with patients
dragging their foot while walking, and compensating by
abnormally lifting their knee. Current surgical strategies to
treat drop foot syndrome include single and split dynamic
tendon transposition of the posterior tibial tendon as well
as the “bridle procedure,” with tendon insertion to the
affected muscles of the anterior and lateral muscle
compartments.
INDICATIONS
The main disadvantage of the most commonly performed
procedures is using antagonistic muscles of the posterior
compartment for restoration of the impaired dorsiflex­
ion, which functionally is a contradiction in itself, and
requires extensive patient reeducation to achieve voluntary
contraction.
The neuromusculotendinous transfer of the gastrocne­
mius muscle first described in 1994 overcomes these limita­
tions, allowing complete intuitive functional restoration of
foot dorsiflexion, thus eliminating the need for muscle
reeducation.3,60 The gastrocnemius muscle has an appropri­
ate size, topography, and neurovascular anatomy providing
adequate strength and range of motion.
To be eligible for neuromusculotendinous transfer,
patients must fulfill the following requirements (Box 23.2).
TECHNIQUE
The procedure is carried out under general anesthesia and
under tourniquet control during surgical preparation of the
neurovascular structures. The surgery consists of three
major steps.
Box 23.2  Indications for the
Neuromusculotendinous
Transfer
• Loss of function of the anterior/lateral muscle compartment(s)
caused by direct localized trauma, compartment syndrome
or tumor resection with consequent irreversible post-
traumatic paralysis of the peroneal nerve. Clinically “irrevers-
ible” is defined as the absence of any noticeable clinical
improvement or signs of reinnervation potentials in electro-
myographic studies for a duration of at least 18 months
following the initial trauma or latest surgery
• A viable and expendable branch of the common peroneal
nerve localized distal to the branching of the tibial nerve is
prerequisite and must be identified
• Presence of viable muscles innervated by the tibial nerve
• Sufficient passive joint movement with dorsal flexion of the
ankle joint of at least 0°
• Adequate soft tissue coverage in the anterior distal third of
the affected leg

292
PART 3 — RECONSTRUCTION
zation period, supportive physiotherapy, including active
and passive range of motion exercises and electrostimula­
tion of the transposed muscle, is initiated. Stimulation
therapy is continued until the patient can actively perform
dorsiflexion against the force of gravity without external
resistance (grade 3 according to the Medical Research
Council [MRC] Scale for Muscle Strength).
COMPLICATIONS
In patients who fulfill the above-mentioned criteria,
the neuromusculotendinous transfer technique can be con­
sidered a safe and reliable procedure. Success mainly relies
on the presence of viable neural and musculotendineal
structures, microsurgical experience of the surgeon, and
correct timing of the procedure. General complications
include bleeding and wound healing complications and
postoperative infection or development of compartment
syndrome. Specific complications related to this procedure
may include insufficient muscle reinnervation, immobility-
induced adhesions requiring tenolysis, and imbalance of the
foot due to inadequate distal attachment to the extensor
tendons leading to pro-, or supination malpositioning.
OUTCOMES
At time of writing, the procedure has been performed by
the authors on a total of 18 patients. All patients showed an
improved walking pattern without requiring an ankle–foot
orthesis. The average hospital stay was 8 days (range 4–28
days). Motor reinnervation was observed at an average of 6
months postoperatively. Full active range of motion was
achieved within an average of 18 months. Excellent results
with normal walking pattern and normal EMG findings,
stable joint, and active ROM of ≥40° were achieved in 10
patients; four patients showed good results with sufficient
walking pattern, minimal foot eversion, and active ROM
≥30°. Satisfactory results were seen in three patients demon­
strating sufficient function on EMG, normal walking pattern,
but with occasional dropping of the foot and active ROM
≥20°. Only one patient showed moderate improvement in
walking pattern, with evident dropping of the foot and
active range of motion ≤20°.
The neuromusculotendinous transfer for the treatment
of drop foot allows restoration of voluntary dorsiflexion
without influencing regular plantar flexion and normal
walking patterns. The beauty of this procedure lies in its
simplicity of functional restoration. While prior procedures
paradoxically utilized antagonistic plantar flexing muscles
for reconstruction of impaired dorsal extension, the
described procedure allows restoration of physiologic con­
ditions, requiring no additional patient reeducation.
The first step, and essential for performing the proce­
dure, is, by means of electrostimulation, the identification
of the viable deep branch of the peroneal nerve, responsible
for innervation of the foot extensor musculature. The inci­
sion is carried out in the lateral aspect of the popliteal
region. After exposing the common peroneal nerve, the
deep motor branch is identified, separated from its sur­
rounding vessels, and dissected under microscopic condi­
tions until sufficient length for tension-free nerve coaptation
is achieved.
In the second step, a longitudinal incision along the
distal, dorsal lower leg is performed exposing the lateral
and/or medial gastrocnemius muscle. Dissection continues
further distally, liberating the gastrocnemius muscle from
the underlying soleus muscle and ensuring inclusion of the
superficial tendinous portion of the Achilles tendon. After
exposure and detachment of the distal portion of the gas­
trocnemius muscle, the dissection proceeds proximally to
the muscle origin, isolating the muscle, exposing the neu­
rovascular pedicle, and allowing the muscle to be trans­
ferred anteriorly. After dorsal dissection, the surgeon
proceeds to the anterior lower leg, exposing the tibialis
anterior, extensor digitorum, and extensor hallucis tendons
through separate ventral incisions. After identifying the
anterior extensor tendons, the medial or lateral gastrocne­
mius tendon is transferred anteriorly and sutured to the
extensor tendons superficial to the extensor retinaculum,
in maximal dorsiflexion of the ankle joint. Careful attention
must be paid to equilibrate the tendon attachments in order
to keep the foot in anatomic balance. Utilization of both
gastrocnemius muscles represents an exception and requires
a modification in respect to the method of tendon attach­
ment. The authors always prefer using the medial gastroc­
nemius head since it shows an anatomically more direct
alignment with the dorsum of the foot. The lateral head can
be transferred additionally as a pure static support to correct
a supination-malposition of the foot. Note that in this case,
the lateral head remains innervated by the tibial nerve and
is attached to the peroneus brevis tendon, thus opposing
tension of the transferred medial gastrocnemius muscle and
ensuring equilibration and stabilization of the foot. Sole
functional transfer with nerve coaptation of the lateral gas­
trocnemius head to the deep peroneal nerve always remains
second choice, as it tends to appear bulky and there is no
straight line of pull.
In the last and most crucial step of the procedure, peri­
neural coaptation of the motor branch of the anterior
tibial muscle and the deep branch of the peroneal nerve is
performed under the microscope. Reducing the length of
the tibialis nerve ensures rapid reinnervation of motoric
function.
Following surgery, the leg is immobilized in a padded
plaster cast in maximal dorsiflexion of the ankle joint.
POSTOPERATIVE CONSIDERATIONS
The leg is immobilized for a total of 6 weeks with an ankle–
foot orthesis in a neutral position. Following the immobili­

CHAPTER 23 — Functional Muscle Transfers for Various Purposes
293
18. Furuta S, Sakaguchi Y, Iwasawa M, et al. Reconstruction of the lips,
oral commissure, and full-thickness cheek with a composite radial
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544–7.
19. Kushima H, Iwasawa M, Kiyono M, et al. Functional reconstruction
of total lower lip defects with a radial forearm free flap combined
with a depressor anguli oris muscle transfer. Ann Plast Surg
1997;39(2):182–5.
20. Galyon SW, Frodel JL. Lip and perioral defects. Otolaryngol Clin
North Am 2001;34(3):647–66.
21. Williams EF 3rd, Setzen G, Mulvaney MJ. Modified Bernard-Burow
cheek advancement and cross-lip flap for total lip reconstruction.
Arch Otolaryngol Head Neck Surg 1996;122(11):1253–8.
22. Karapandzic M. Reconstruction of lip defects by local arterial flaps.
Br J Plast Surg 1974;27(1):93–7.
23. Bakamjian VY, Long M, Rigg B. Experience with the medially based
deltopectoral flap in reconstructive surgery of the head and neck.
Br J Plast Surg 1971;24(2):174–83.
24. Converse JM, McCarthy JG, Littler JW. Reconstructive plastic
surgery: principles and procedures in correction, reconstruction,
and transplantation. 2nd ed. Philadelphia: WB Saunders; 1977.
25. Sakai S, Soeda S, Endo T, et al. A compound radial artery forearm
flap for the reconstruction of lip and chin defect. Br J Plast Surg
1989;42(3):337–8.
26. Carroll CM, Pathak I, Irish J, et al. Reconstruction of total lower
lip and chin defects using the composite radial forearm–palmaris
longus tendon free flap. Arch Facial Plast Surg 2000;2(1):53–6.
27. Shinohara H, Iwasawa M, Kitazawa T, et al. Functional lip recon­
struction with a radial forearm free flap combined with a masseter
muscle transfer after wide total excision of the chin. Ann Plast Surg
2000;45(1):71–3.
28. Ninković M, Stenzl A, Hess M, et al. Functional urinary bladder
wall substitute using a free innervated latissimus dorsi muscle flap.
Plast Reconstr Surg 1997;100(2):402–14.
29. Stenzl A, Ninkovic M, Kölle D, et al. Restoration of voluntary emp­
tying of the bladder by transplantation of innervated free skeletal
muscle. Lancet 1998;351(9114):1483–5.
30. Stenzl A, Ninkovic M, Willeit J, et al. Free neurovascular transfer
of latissimus dorsi muscle to the bladder. I. Experimental studies.
J Urol 1997;157(3):1103–8.
31. Mathes SJ, Nahai F. Reconstructive surgery: principles, anatomy, &
technique. New York: Churchill Livingstone; 1997.
32. Ono I, Gunji H, Tateshita T, et al. Reconstruction of defects of the
entire vermilion with a buccal musculomucosal flap following
resection of malignant tumors of the lower lip. Plast Reconstr Surg
1997;100(2):422–30.
33. Mazzola RF, Lupo G. Evolving concepts in lip reconstruction. Clin
Plast Surg 1984;11(4):583–617.
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4. O’Brien BM, Lawlor DL, Morrison WA. Microneurovascular free
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8. Manktelow RT, Zuker RM. The principles of functioning muscle
transplantation: applications to the upper arm. Ann Plast Surg
1989;22(4):275–82.
9. Doi K, Sakai K, Ihara K, et al. Reinnervated free muscle transplan­
tation for extremity reconstruction. Plast Reconstr Surg 1993;91(5):
872–83.
10. Jackson IT. Local flaps in head and neck reconstruction. St Louis:
Mosby; 1985. p. vii.
11. Gillies HD, Millard DR. Principles and art of plastic surgery. Boston:
Little Brown; 1957.
12. Baker SR. Local flaps in facial reconstruction. 3rd ed. Philadelphia:
Elsevier, Saunders; 2014.
13. Sadove RC, Luce EA, McGrath PC. Reconstruction of the lower lip
and chin with the composite radial forearm-palmaris longus free
flap. Plast Reconstr Surg 1991;88(2):209–14.
14. Luce EA. Reconstruction of the lower lip. Clin Plast Surg 1995;
22(1):109–21.
15. Koshima I, Inagawa K, Urushibara K, et al. Combined submental
flap with toe web for reconstruction of the lip with oral commis­
sure. Br J Plast Surg 2000;53(7):616–19.
16. Wei FC, Tan BK, Chen IH, et al. Mimicking lip features in free-flap
reconstruction of lip defects. Br J Plast Surg 2001;54(1):8–11.
17. Sakai S, Soeda S, Uchida A, et al. Use of a combined groin-tensor
fasciae latae flap for reconstruction of a full-thickness defect of the
abdominal wall. Br J Plast Surg 1985;38(4):492–6.
Expert Commentary
Milan Stevanovic, MD, and Frances Sharpe, MD
Functional free muscle transfers sit at the top of the reconstruc-
tive ladder for salvaging function when no other alternatives are
available. Dr. Ninkovic et al have presented novel uses of func-
tional muscle transfers for complex and difficult problems
including restoration of lower lip function (including application
of neurotization for sensory reconstruction), functional abdomi-
nal wall reconstruction, detrusor muscle reconstruction for the
acontractile bladder, and functional muscle transfer for restora-
tion of dorsiflexion in the foot. Although the applications are
novel, the principles of functional free muscle transfer remain
the same.
Patient considerations should include the age and medical
status of the patient. In upper extremity reconstruction we have
not had good restoration of muscle function in patients over
the age of 45. Medical comorbidities that could compromise
successful outcome, such as vascular disease, immunocom-
promised conditions, and diabetes, are contraindications to
functional muscle reconstruction in the upper extremity.
Patients should also be able to withstand the rigors of pro-
longed anesthesia. Donor considerations must include the
power and excursion of the donor muscle and donor site mor-
bidity. Surgical teamwork to quickly reestablish muscle circula-
tion is critical to preserving muscle function, as muscle loss
increases in a non-linear relationship with increasing ischemia
time. Recipient site considerations, regardless of the applica-
tion, require the availability of an expendable motor nerve. At
the time of muscle transfer, strong and appropriate muscle
origin and insertions must be established, the muscle resting
length should be accurately restored, and the neurorrhaphy of
the donor motor nerve must be as close as possible to the
recipient muscle. Rehabilitation of these patients requires
patience both in the initial stage while waiting for muscle re-
innervation as well as in the later stages of therapy. Transferred
muscles are fragile and more susceptible to stretch injury and
need to be protected during the recovery process.

294
PART 3 — RECONSTRUCTION
34. Pribaz J, Stephens W, Crespo L, et al. A new intraoral flap: facial
artery musculomucosal (FAMM) flap. Plast Reconstr Surg 1992;
90(3):421–9.
35. Pribaz JJ, Meara JG, Wright S, et al. Lip and vermilion reconstruc­
tion with the facial artery musculomucosal flap. Plast Reconstr Surg
2000;105(3):864–72.
36. Koshima I, Nanba Y, Tutsui T, et al. Dynamic reconstruction of
large abdominal defects using a free rectus femoris musculocutane­
ous flap with normal motor function. Ann Plast Surg 2003;50(4):
420–4.
37. Iida T, Mihara M, Narushima M, et al. Dynamic reconstruction of
full-thickness abdominal wall defects using free innervated vastus
lateralis muscle flap combined with free anterolateral thigh flap.
Ann Plast Surg 2013;70(3):331–4.
38. Tiengo C, Giatsidis G, Azzena B. Fascia lata allografts as biological
mesh in abdominal wall repair: preliminary outcomes from a retro­
spective case series. Plast Reconstr Surg 2013;132(4):631e–639e.
39. Kim SW, Han SC, Hwang KT, et al. Reconstruction of infected
abdominal wall defects using latissimus dorsi free flap. ANZ J Surg
2013;83(12):948–53.
40. Cederna JP, Davies BW. Total abdominal wall reconstruction. Ann
Plast Surg 1990;25(1):65–70.
41. Iwahira Y, Maruyama Y, Shiba T. One-stage abdominal wall recon­
struction with oblique abdominal fasciocutaneous flaps. Ann Plast
Surg 1987;19(5):475–7.
42. Hobar PC, Rohrich RJ, Byrd HS. Abdominal-wall reconstruction
with expanded musculofascial tissue in a posttraumatic defect. Plast
Reconstr Surg 1994;94(2):379–83.
43. Sensoz O, Ustuner TE, Taner OF. Use of a sartorius myofasciocu­
taneous flap for reconstruction of a large, full-thickness abdominal
wall defect. Ann Plast Surg 1990;25(3):193–6.
44. Brown DM, Sicard GA, Flye MW, et al. Closure of complex abdomi­
nal wall defects with bilateral rectus femoris flaps with fascial exten­
sions. Surgery 1993;114(1):112–16.
45. Tesh KM, Dunn JS, Evans JH. The abdominal muscles and vertebral
stability. Spine (Phila Pa 1976) 1987;12(5):501–8.
46. Thevenon A, Delcambre B. Movements of the lumbar spine. A bio­
mechanical study. Rev Rhum Mal Osteoartic 1988;55(5):367–73.
47. Vaidyanathan S, Krishnan KR, Soni BM, et al. Unusual complica­
tions of intermittent self-catheterisation in spinal cord injury
patients. Spinal Cord 1996;34(12):745–7.
48. Di Benedetto P. Clean intermittent self-catheterization in neuro-
urology. Eur J Phys Rehabil Med 2011;47(4):651–9.
49. Madjar S, Appell RA. Impaired detrusor contractility: anything
new? Curr Urol Rep 2002;3(5):373–7.
50. Koleilat N, Sidi AA, Gonzalez R. Urethral false passage as a compli­
cation of intermittent catheterization. J Urol 1989;142(5):1216–17.
51. Wyndaele JJ. Complications of intermittent catheterization: their
prevention and treatment. Spinal Cord 2002;40(10):536–41.
52. Kuhn W, Rist M, Zaech GA. Intermittent urethral self-
catheterisation: long term results (bacteriological evolution,
continence, acceptance, complications). Paraplegia 1991;29(4):
222–32.
53. Tanagho EA, Schmidt RA. Electrical stimulation in the clinical man­
agement of the neurogenic bladder. J Urol 1988;140(6):1331–9.
54. Brindley GS, Rushton DN. Long-term follow-up of patients with
sacral anterior root stimulator implants. Paraplegia 1990;28(8):
469–75.
55. Gakis G, Ninkovic M, van Koeveringe GA, et al. Functional detrusor
myoplasty for bladder acontractility: long-term results. J Urol 2011;
185(2):593–9.
56. Stenzl A, Ninković M. Restoring voluntary urinary voiding using a
latissimus dorsi muscle free flap for bladder reconstruction. Micro­
surgery 2001;21(6):235–40.
57. Van Savage JG, Perez-Abadia G, Palanca LG, et al. Comparison of
the experience with acute and chronic electrically stimulated
detrusor myoplasty. Neurourol Urodyn 2002;21(5):516–21.
58. Garusi C, Lohsiriwat V, Brenelli F, et al. The value of latissimus
dorsi flap with implant reconstruction for total mastectomy after
conservative breast cancer surgery recurrence. Breast 2011;20(2):
141–4.
59. Delay E, Gounot N, Bouillot A, et al. Autologous latissimus breast
reconstruction: a 3-year clinical experience with 100 patients. Plast
Reconstr Surg 1998;102(5):1461–78.
60. Ninković M, Ninković M. Neuromusculotendinous transfer: an
original surgical concept for the treatment of drop foot with long-
term follow-up. Plast Reconstr Surg 2013;132(3):438e–45e.

295
Nerves
Kazuteru Doi  |  Alison Snyder-Warwick
24 
“While it is the quality of the recovery which is the principal
objective of nerve repair, both the pathological basis of the injury
and the limits of surgery are, as we shall see, anatomical.
Nowhere else are anatomy, physiology, and pathology more
intimately related or more mutually interdependent.”
(SIR SYDNEY SUNDERLAND, 1968)
INTRODUCTION AND HISTORICAL NOTES
The peripheral nervous system (PNS) embodies unique
anatomical structure and function that contributes im­
mensely to human quality of life. Through the ages, the
importance of the PNS has been recognized, but func­
tion and structure were often misinterpreted or consid­
ered mystical. The Alexandrians, specifically Herophilus
of Chalcedon (335–280bc) and Erasistratus of Chios
(310–250bc) are credited with differentiating nerves from
tendons and even proposed the presence of different
nerves for motor and sensory functions.1 Erasistratus distin­
guished nerves, in addition to arteries and veins, as one of
the three main channels in the body, but proposed that
“animal spirits” flowed through the nerves, subserving sen­
sation and movement.2 The electrical basis of nerve and
muscle potentials was better realized after Arrhenius
(1859–1927) and other physical chemists demonstrated the
properties of ions in electrolyte solutions, and nerves and
muscles were found to conform to membrane potentials
predicted by the Nernst equation.3 Technological advances
during the First World War allowed revelation of the prop­
erties of nerve action potentials.4 Continued advance­
ment of our knowledge of the structure and function of
the PNS, as well as the instruments to study it have allowed
us to not only better understand PNS pathology, but intri­
cately modify and repair it to better improve the human
experience.
ANATOMICAL CONSIDERATIONS
The PNS is composed of neurons and supporting glial cells
called Schwann cells. Neurons may be motor, sensory, or
mixed. The neuron cell bodies are located in the spinal
cord, and long cytoplasmic peripheral extensions called
axons carry electrical impulses to or from their targets.
Axons are separated from one another via endoneurium,
and organized groups of axons are called fascicles (Fig.
24.1). The perineurium surrounds fascicles, and the inter­
nal epineurium separates the perineurial-ensheathed
fascicles. The external epineurium encompasses all fascicles
and the internal epineurium and establishes the nerve sil­
houette. The mesoneurium is located external to the epi­
neurial layers, is continuous with the perineurium, and is
critical in longitudinal gliding of the nerve. Schwann cells
(SCs) are subdivided into two main types: myelinating SCs
and non-myelinating SCs. Myelinating SCs insulate and
protect axons by iteratively wrapping their membranes to
form the multilaminated myelin sheath, ensuring that nerve
impulses travel quickly and efficiently.5 Independent of
their functions in myelination, Schwann cells also provide
vital trophic support to neurons.6,7 Loss of myelin can lead
to permanent neuron loss, significant pain, and morbidity,
and ultimately paralysis. Non-myelinating SCs are located
along axons and at the neuromuscular junction and provide
many functions including trophic support, phagocytosis,
synaptic transmission, and support for reinnervation.8–12
More knowledge regarding the importance of non-
myelinating SCs is evolving constantly.
Figure 24.1  Nerve anatomy.
CCF
Fascicle
Axon
Myelin
Node of Ranvier
Endoneurium
Perineurium
Epineurium (internal)
Epineurial sheath
Blood vessels
PART 3 — RECONSTRUCTION
SECTION A — MICROSURGERY TECHNIQUES

296
PART 3 — RECONSTRUCTION
degree of nerve injury predicts prognosis for recovery or
lack thereof. In 1943, Seddon initially categorized nerve
injury into neurapraxia, axonotmesis, and neurotmesis.25
This classification system was later elaborated by Sunder­
land in 1951, into five degrees of nerve injury, and he
alluded to possible combinations of these degrees of injury.26
Mackinnon popularized the mixed pattern, or sixth degree,
of injury, which describes multiple injury patterns at the
same level (Table 24.1).
Both first- and second-degree injuries can be grouped
into favorable injuries, are expected to recover spontane­
ously, and therefore are typically managed conservatively. A
first-degree injury, or “neurapraxia,” is an ischemic injury or
conduction block which may have segmental demyelination,
but no interruption of axons or surrounding connective
tissue. As a result, no axonal degeneration occurs, and com­
plete recovery is expected within 12 weeks after axonal
remyelination is complete. In cases of chronic nerve com­
pression, a permanent conduction block may ensue. Second-
degree injuries, or “axonometric injuries,” involve axonal
disruption but persistent continuity of surrounding connec­
tive tissue sheaths, including the basal lamina. The axons
distal to the injury site undergo Wallerian degeneration,27
and recovery is expected in alignment with nerve regenera­
tion at a rate of 1 mm daily.28 Motor nerve injuries distant
to the target muscle may be at risk for incomplete recovery
due to the deleterious microenvironment occurring with
prolonged denervation in both the nerve and target
muscle.29–34
More severe peripheral nerve injuries require surgical
intervention. Third-degree injuries are also axonometric
injuries, with injury to both axons and the endoneurium.
Fibrosis within the endoneurium prevents complete axonal
regeneration and recovery. Surgical intervention to release
scarred tissues or areas of entrapment is indicated to opti­
mize functional recovery. In the absence of surgery, recovery
is incomplete. Typically, outcomes following decompression
are superior to excision of the injured nerve and grafting,
except in cases of complex regional pain syndromes. Fourth-
and fifth-degree injuries are unfavorable. Fourth-degree
Fascicular nerve patterns may be monofascicular with just
one large fascicle; oligofascicular, consisting of a few fascicles;
and polyfascicular, consisting of many fascicles of varying
sizes. In the proximal extremities a monofascicular pattern
predominates, consisting of both motor and sensory nerves
with considerable plexus formation among fascicles. Moving
more distally, the plexus formation simplifies and a more
specific, polyfascicular pattern with differentiation into
motor and sensory regions closer to the end-target, is
found.13,14
Knowledge of internal nerve topography allows specific
fascicular alignment during repair to enhance efficiency
and specificity of recovery. Topography for specific nerves
has been described and results from intraoperative electri­
cal stimulation to differentiate motor and sensory regions.15,16
Nerve transfers, such as the double fascicular transfer,17–19
are a direct application of the knowledge of internal
topography.
The vascular supply for nerves is via two main systems,
collectively referred to as the “vasa nervorum.” The meso­
neurium provides the extrinsic vascularity, while the endo­
neurium houses the intrinsic nerve vascular supply. The
extrinsic supply was described by Ranvier as early as 1878,
upon which Ramage further elaborated.20 The intrinsic
supply consists of fragile capillary networks that are easily
disrupted.21 Vasa nervorum have been described in detail
for specific nerves.22,23 The vasa nervorum are linked to
injury and repair.24 Flow is increased in the extrinsic
and intrinsic systems in the acute period following injury
with angiogenesis occurring in the perineurium and epi­
neurium approximately 2 weeks after injury in the rat
model. After prolonged denervation (>6 months), vascular
flow is diminished, and this phenomenon reverses after
reinnervation.24
CLASSIFICATION OF NERVE INJURY
Correct classification of nerve injury is paramount to plan­
ning appropriate management strategies. Establishing the
Table 24.1  Degrees of nerve injury
Degree of injury
Recovery
Rate of recovery
Surgical
management
Electrodiagnostic
studies
Favorable
I
Neurapraxia
Complete
Up to 12 weeks
−
No fibrillations
II
Axonotmesis
Partial +
1 mm daily
±
Fibrillations and MUPs
III
Axonotmesis
Partial
1 mm daily
±
Fibrillations and MUPs
Unfavorable
IV
Neuroma-in-continuity
None
None
+
Fibrillations, no MUPs
V
Neurotmesis
None
None
+
Fibrillations, no MUPs
VI
Mixed injury (I–V)
Some fascicles (II, III)
Varies with injury (I–V)
+
Varies with injury
MUPs, motor unit potentials.

CHAPTER 24 — Nerves
297
PLANNING THE RECONSTRUCTION
TIMING OF NERVE REPAIR/RECONSTRUCTION
Recovery following peripheral nerve injury is influenced not
only by the degree of nerve injury, but also by the relative
distance of the injury to the end-target. When planning
motor reconstruction, consideration must be given to the
timing of the nerve injury, timing and type of nerve repair
or reconstruction, and required nerve regeneration dis­
tance for reinnervation of the target muscle. There is a
critical window of approximately 12–18 months, during
which functional reinnervation is possible following injury.
Beyond this timeframe, muscle and nerve are unable to
interface for a multitude of reasons.
After nerve injury, neurons, Schwann cells, and muscle
all undergo changes in morphology and genetic expression
to prepare and allow for regeneration to occur.31,53 Pre­
viously, muscle was thought to be the primary contributor
to poor recovery with prolonged denervation.54 Myofibril
reabsorption, actin and myosin catabolism, increased col­
lagen deposition in the extracellular space, and decreased
muscle cell size occur due to proteasomes associated with
the ubiquitin-proteasome pathway. Myocytes may undergo
apoptosis, and muscle becomes less vascular due to capillary
loss.55,56 These changes occur non-uniformly throughout
muscle. Muscle fibers group with reinnervation, and
although motor endplate number may increase in the
re­maining viable muscle during reinnervation, functional
recovery is poor.55 Loss of muscle cross-sectional area in
denervation atrophy corresponds with decreased contractile
force. With prolonged denervation, myofibril disorganiza­
tion and collagen replacement result in decreased specific
force capacity, which is permanent.57 Axons distal to the
injury undergo fragmentation and Wallerian degenera­
tion, with loss of their myelin sheath, as outlined above.
Denervated SCs dedifferentiate to a less mature state that
supports neuroregeneration and neuromuscular junction
reinnervation.58–60 Prolonged denervation and axotomy
periods, however, lead to progressively poor neuroregenera­
tive conditions involving not only the muscle, but also
the nerve.29–34 There is increasing evidence regarding
the deleterious effect of SC senescence on neuroregenera­
tion.61 The complete microenvironment, therefore, becomes
less supportive for functional recovery with prolonged
denervation.
It is this time-sensitivity for motor recovery that is integral
for reconstructive planning. The time interval from injury
to presentation to the peripheral nerve surgeon, as well as
the location of the nerve lesion and its distance from the
motor end-target, may preclude optimal or even feasible
functional motor recovery via traditional methods. Proximal
nerve injuries that are distant from their end-target may not
be appropriate for reconstruction at the site of the lesion,
even with immediate patient presentation. Nerve transfers
provide a solution to this reconstructive challenge by recon­
structing the deficit near the end-target rather than at a
distant injury site. Nerve transfers are discussed further in
a later section.
Sensory reinnervation is not limited by such time con­
straints, although the unfavorable microenvironment
related to axons and SCs continues to be investigated.
injuries, or “neuromas-in-continuity,” include injuries to
axons, endoneurium, and perineurium. No potential for
spontaneous recovery exists with fourth-degree injuries, and
surgical intervention with neuroma excision and grafting is
required. Superior long-term outcomes with neuroma exci­
sion and grafting, rather than neurolysis have been demon­
strated in the example of birth-related brachial plexus
injuries.35 Fifth-degree nerve injuries, or “neurotmesis,”
result from complete nerve transection, or interruption of
axons and all connective tissues (endoneurium, perineu­
rium, and epineurium). Surgical management is required.
Sixth-degree, or “mixed pattern injuries” describe nerve
injuries that incorporate two or more injury patterns at the
same level. These injury types are the most complex, as
consideration must be given to all involved injury types with
particular emphasis to not downgrade function.
The determination of nerve injury is often aided
with electrodiagnostic studies. The second author (ASW)
employs electromyography (EMG) to augment the clinical
picture in patients with unclear degrees of injury. Fibrilla­
tions, which are indicative of nerve injury, appear within
4–6 weeks of injury, but motor unit potentials (MUPs),
which result from adjacent axonal sprouting predict the
capacity for spontaneous recovery, may not appear on EMG
testing until 8–12 weeks after injury. EMG testing can,
therefore, be employed 3 months from the time of injury
to determine prognosis for spontaneous recovery. The
absence of MUPs is an indication to proceed with surgical
intervention. Motor unit potentials are not seen in fourth-
and fifth-degree injuries, and may or may not be seen in
third-degree injuries (Table 24.1). EMG testing can be par­
ticularly helpful for determining prognosis in third-degree
and mixed injuries.
WALLERIAN DEGENERATION AND
NEUROREGENERATION
Changes occur in both the proximal and distal neuron after
injury. Dr Augustus Waller first described the “alterations
which take place in the elementary fibres of the nerve after they have
been removed from their connection with the brain or spinal marrow”
in sections of the glossopharyngeal and hypoglossal nerves
of the frog.36 Termed “Wallerian degeneration,” the distal
axonal segment undergoes degenerative changes in which
SCs, fibroblasts, myocytes, and injured axons express neu­
rotrophic factors in response to injury as degrading neural
elements are phagocytosed.37–44 Axons in the proximal
segment undergo retraction and a brief dormant phase
before formation of a regenerating unit. The regenerating
unit elongates and sprouts multiple axon branches.31
Remaining endoneurial tubes termed “Bands of Bungner”45,46
and proregenerative Schwann cells guide axons to their
targets.47–49 Extreme proximal axonal injuries and avulsions
may lead to death of the cell body. Similar processes of Wal­
lerian degeneration and neuroregeneration occur in the
setting of nerve autografting and are required for proper
regeneration across the graft.48 Increased knowledge of the
molecular signaling events occurring during these degen­
erative and regenerative processes may lead to therapeutic
interventions for management of neurodegenerative
disorders.43,44,50–52

298
PART 3 — RECONSTRUCTION
OPERATIVE CONSIDERATIONS
NEURORRHAPHY TECHNIQUES
Nerve repair and reconstruction must be performed with a
healthy nerve. Healthy nerves are supple with discernible
fascicles that tend to gently pout, or minimally protrude,
from a sharply cut end. Elegant nerve reconstructions per­
formed within the zone of nerve injury have no functional
value. In the case of an acute, sharp nerve transection, surgi­
cal debridement of the transected nerve ends is probably
unnecessary. However, in cases of nerve avulsion, crush,
blast, or mixed patterns of injury, neural debridement is
required. Demarcation of injured nerve ends is complete 3
weeks after injury.77 Careful dissection is required to identify
the nerve itself. Electrical stimulation should always be uti­
lized intraoperatively to augment dissection and confirm
diagnosis. Transected nerves stimulate for 72 h after injury
before neurotransmitters are exhausted. Beyond 72 h after
nerve transection, nerve stimulation will no longer be pos­
sible. Neural debridement begins with division at the most
scarred portion of the neuroma or transected stumps and
progresses in a step-wise, cut-by-cut fashion, which is termed
“breadloafing” (Dr Susan Mackinnon, pers. comm.), until a
healthy fascicular pattern is observed. Frozen sections may
Currently, it is accepted that sensory reconstruction may be
performed at any time and may traverse any distance,
although the true boundaries of sensory reconstruction
remain unknown.
SENSORY PROTECTION OF
DENERVATED MUSCLE
Given that time to motor reinnervation is inversely related
to functional outcome, opportunities to provide protec­
tion for denervated muscle during the neuroregeneration
period have been pursued. Protection of denervated
muscle via sensory innervation has been described.62–66
Temporary or permanent sensory protection has demon­
strated increased muscle mass,62–65,67 increased compound
motor action potentials,64 and decreased levels of glial
cell line-derived neurotrophic factor mRNA68 compared
with unprotected controls, suggesting a trophic effect
for denervated muscle fibers. Sensory-protected muscles
demonstrate retained muscle fiber organization,64,66 a
trend in increased motor endplate numbers,65 and reduc­
tion in muscle spindle degeneration.69 The functional
benefits for sensory protection of denervated muscle
remain uncertain,66 but clinical improvements have been
reported by Bain et al.70 after saphenous nerve protection
of the tibialis anterior branch of the peroneal nerve
and the gastrocnemius branch of the tibial nerve in the
setting of complete sciatic nerve palsy following total hip
arthroplasty.
PRINCIPLES OF NERVE REPAIR
EQUIPMENT
Peripheral nerve surgery should be performed by an
experienced or well-trained microsurgeon familiar with
peripheral nerve anatomy and physiology, with the proper
available equipment, team, and facilities. Nerve surgery is
best performed with the use of the operating microscope
with appropriate lighting, although some surgeons prefer
the use of ≥4.0 loupe magnification. The neurotomy
instrument set (S&T, USA) greatly facilitates cutting the
nerve sharply (Fig. 24.2) to maintain all fascicles in the
same plane. We prefer 10-0 nylon with an atraumatic
needle for perineurial suture and 10-0–8-0 nylon for epi­
neurial sutures. Larger suture materials are not used, even
when major nerves are being repaired. Suture materials
for nerve repair allow approximation and alignment of the
nerve ends, not strength to withstand tension. All nerve
coaptations should be tension-free. Sharp-tip needles are
imperative, and each needle should be used for only four
or five stitches, since multiple passes through the nerve
blunts the tip of the needle. Dull needle tips may dislodge
delicate fascicles and prevent atraumatic needle passage.
Fibrin may be used as a safe alternative to microsutures for
neural coaptations, such as in birth-related brachial plexus
surgery, where proximal stumps may be located within
spinal foramina, or as reinforcement for a sutured neural
coaptation.71–76
Figure 24.2  (A,B) Victor Meyer neurotomy apparatus.
A
B

CHAPTER 24 — Nerves
299
fascicles between each nerve stump. In acute cases (<3 days
after injury), the distal motor nerve can be distinguished by
electric stimulation. Orientation of the proximal fascicles,
however, requires electrophysiologic or biochemical exami­
nation. We do not routinely apply this time-consuming
method, and rely on the orientation of the epineurial vessels
for proper alignment.
Historically, controversy exists between proponents of the
epineurial and the perineurial suture,80–82 but both tech­
niques and their modifications may be utilized in the clini­
cal setting. Epineurial suturing may be appropriate, for
example, to repair a sharp laceration of the median nerve
at the wrist, while intercostal nerve transfers require a peri­
neurial suture technique. For all techniques, any stray or
escaping fascicles should be trimmed to allow straight appo­
sition of fascicular ends. In this section, each technique is
described in detail.
Epineurial Suture
Following orientation of the fascicles, the epineurial suture
commences with two laterally placed 8-0 or 9-0 nylon sutures,
passing the needle from the epineurium to the internal
epineurium (Fig. 24.4A), tied to align the fascicles between
each nerve stump, taking care not to cinch sutures tightly.
Interrupted sutures, as necessary, are added between the
first two stay sutures on the anterior aspect. The nerve is
then rotated by manipulation of the lateral stay sutures, so
that the posterior epineurium can be gently approximated.
Tight sutures tend to twist the fascicles within the epineu­
rium (Fig. 24.5A), which can be prevented by the assistant
applying mild traction to both sites of the nerve (Fig. 24.5B).
This technique is useful to suture the nerve in a fresh wound
or for nerve transfer, where the epineurium is thin and
retracted.
Perineurial Suture
For perineurial coaptations, the mesoneurium and external
and internal epineurium are removed from both ends of
the nerve stump with microsurgery scissors. Following ori­
entation and matching of fascicles between both stumps,
Figure 24.3  A tension-free nerve coaptation follows a lazy “s”
pattern.
Coaptation site
Coaptation site
Figure 24.4  Standard techniques of nerve suturing. (A) Epineurial suture. (B) Perineurial suture. (C) Epiperineurial suture.
A
C
B
be performed intraoperatively to verify absence of fibrosis
before proceeding with nerve repair.
All neural coaptations must be performed free of tension.
This technical detail is imperative to successful outcomes.
Excessive tension prevents neuroregeneration due to im­
paired microvascular flow through the vasa nervorum at the
endoneurium and due to creation of increased scarring.78,79
Adjacent joints should never be flexed to allow primary
nerve coaptation. Ideally, nerves should have a lazy “s”
pattern at coaptation sites (Fig. 24.3), and joints should be
fully ranged to ensure no tension with changes in position.
This technique not only ensures optimal regenerative con­
ditions with vascularity, but also minimizes the need for
postoperative splinting and therefore allows faster initiation
of nerve gliding with movement to minimize scar formation.
If this is not possible, a nerve graft or some other nerve
repair technique should be employed. Similarly, sutures
should not be pulled taut, but instead should be sufficient
to just approximate nerve stumps without bending the fas­
cicular ends, which impedes regeneration.
Whenever possible, proper fascicular orientation should
be performed for coaptation of the motor and sensory

300
PART 3 — RECONSTRUCTION
reconstruction are to maximize functional restoration safely
and efficiently, while minimizing any donor deficit. The
mechanism and degree of injury; location of lesion; age of
patient; associated injuries including life-threatening or sys­
temic disease or injury, adjacent vascular injuries or complex
soft tissue wounds; the time since the injury occurred; and
the availability of donor tissues are considered to deter­
mine the optimal reconstruction for an individual patient.
Specific treatment algorithms have been previously re­
viewed.77,79,83–85 Primary nerve repair, interpositional nerve
grafting, grafting with nerve substitutes, nerve transfers, and
nerve allotransplantation may be used. Nerve allotransplan­
tation and nerve substitutes are covered thoroughly in
Chapter 68 and therefore are not discussed here.
PRIMARY NERVE REPAIR
Direct repair of transected ends is the repair of choice when
appropriate conditions exist. Primary repair is typically per­
formed after sharp transection (fifth-degree, unfavorable)
injuries. Repair is ideally performed within 72 h of injury to
facilitate the use of electrical stimulation for identification
of distal nerve stumps. A simple, interrupted microsuturing
technique is used to reapproximate nerve ends (Fig. 24.4A).
NERVE GRAFTS
Autogenous nerve grafts are the gold standard reconstruc­
tion for nerve gaps.17 Nerve autografts provide both a matrix
and viable SCs to support nerve regeneration.21,77 When
planning a nerve repair, the length of the nerve gap, the
diameter of the injured nerve, the fascicular pattern of both
ends of the nerve stumps, and the vascularity of the sur­
rounding recipient bed are taken into consideration for
selection of the donor nerve and its length. We most fre­
quently utilize the sural nerve as a donor autograft due to
the ease of harvest and minimal donor morbidity, but other
frequently used donor autografts and their characteristics
are reviewed in Chapter 68 (Table 68.2). The median and
lateral antebrachial cutaneous (MABC and LABC) nerves
serve as excellent donors for upper extremity reconstruc­
tion. Motor nerves are ideally grafted with motor autografts
for improved regeneration,46,86–90 due to preferential motor
each fascicle is coapted with 10-0 nylon by passing the
needle through the perineurium close to the edge, using a
small bite so as not to slip off both ends of the fascicles (Fig.
24.4B). The assistant surgeon can hold both ends of the
nerve under mild tension to facilitate this maneuver. The
repair of each fascicle is completed with three or four
sutures of 10-0 nylon. All matched fascicles are connected
in the same fashion.
EPIPERINEURIAL COMBINED SUTURE
The senior author (KD) prefers epiperineurial combined
sutures even when the conventional epineurial suture is
indicated because this allows more accurate coaptation
of the peripheral fascicles within the epineurium. Nylon
sutures (8-0 or 9-0) are passed through the epineurium and
perineurium simultaneously with the same pass of the
needle, and tied (Fig. 24.4C). In this technique, the lateral
stay sutures are not applied because the remaining fascicles
cannot be seen after the two lateral sutures are placed.
Suturing is performed in a circumferential order, taking
care to coapt the remaining fascicles as much as possible
(Fig. 24.6).
NERVE RECONSTRUCTION
Nerve repair and reconstruction in the 21st century may
incorporate multiple techniques. The goals of PNS
Figure 24.5  (A) Twisting of the fascicles within the epineurium by
tight suture, which can (B) be prevented by the assistant applying
mild traction to both sites of the nerve.
A
B
Figure 24.6  Circumferential order of epiperineurial stitches.

CHAPTER 24 — Nerves
301
VNG compared with non-vascularized nerve autograft in a
single patient case study.104 Terzis and Kostopoulos105 re­
ported their experience with 14 VNGs in lower extremity
reconstruction and noted the benefits of a VNG for long
defects (>13 cm) and in traction injuries (due to the lengthy
zone of injury), especially if performed within 6 months
after the injury. Still, VNG are not frequently used, possibly
due to the length and complexity of the procedure, limited
donors, and availability of alternative reconstructive tech­
niques. The coaptation techniques for conventional sural
nerve grafting, interfascicular nerve grafting, and vascular­
ized nerve grafting are reviewed.
CONVENTIONAL SURAL NERVE GRAFTING
The sural nerve (Fig. 24.9) is a frequent donor nerve due
to its relative ease of harvest and well-tolerated donor
deficit. The proximal portion of the sural nerve, just distal
to the popliteal crease, is typically free of branches. A
nerve stripper device can be utilized to facilitate harvest
of the nerve, and multiple types of incisions may be
employed. The caliber of the nerve increases distally near
the ankle, and this knowledge may be advantageous for
improving the size match of the coaptation, depending on
the recipient nerve. The surrounding mesoneurium and
fatty tissue around the harvested sural nerve are removed
with microsurgery scissors under the operating micro­
scope (Fig. 24.10A) and placed between both ends of the
recipient nerve. Depending on the length of nerve gap
and diameter of the recipient nerve, the sural nerve is
folded and cut into segments long enough to bridge the
gap (Fig. 24.10B). The direction of the donor nerve is not
of major concern if no branches are present. If branches
are present, the nerve is reversed to prevent axonal
drop-off.
regeneration, or the tendency for regenerating motor axons
to prefer motor pathways over sensory pathways when given
the choice,91 but available motor donors are typically quite
limited. Kawamura et al.92 demonstrated that motor, sensory,
and mixed nerve grafts result in equivalent regeneration for
purely motor or purely sensory unifascicular nerves and
conclude that the advantage of motor grafts exists in the
setting of regeneration of mixed motor and sensory nerves
due to the increased space in motor grafts for motor and
sensory regeneration competition to occur. Depending on
the discrepancy in diameter between the recipient and
donor nerves, the number of necessary nerve cables should
be calculated. We usually assume a 20% longer nerve graft
than the actual length of gap to prevent tension after nerve
grafting. All nerve repairs should be performed in a tension-
free manner, and nerve grafts should have the same lazy “s”
configuration as any coaptations (Fig. 24.3).
Nerve grafts may include standard interpositional auto­
grafting, interfascicular autografting, or vascularized nerve
autografting. Endoscopic techniques are frequently em­
ployed for sural nerve graft harvest.93–96 Vascularized nerve
grafts (VNG) are used less frequently clinically, but may be
beneficial for a long-segment nerve defect, large diameter
nerve, or a severely scarred recipient bed, which obstructs
neovascularization of the nerve graft. Small diameter nerve
grafts spontaneously revascularize, but larger caliber nerves
do not revascularize as readily, and therefore may benefit
from a VNG.97 Nerve grafts in severely scarred tissues may
benefit from replacement of the surrounding tissue by a
vascularized (free or pedicled) fasciocutaneous flap or
VNG, even for a short nerve gap.98 The vascularized sural
nerve and ulnar nerve grafts are well-described (Figs 24.7,
24.8).99–103 Superior regeneration has been reported in a
Figure 24.7  Vascular supply of the sural nerve. A – Lateral sural
nerve. B – Sural artery. C – Muscular perforating branch of the pos­
terior tibial artery. D – Direct cutaneous branch of the peroneal artery.
E – Medial sural nerve.
B
C
A
E
D
Figure 24.8  A – Harvesting of vascularized sural nerve graft. B –
based on the superficial sural artery and vein. C – Common peroneal
nerve.
B
C
A

302
PART 3 — RECONSTRUCTION
INTERFASCICULAR NERVE GRAFTING
Fascicles of both ends of the recipient nerve are separated
into fascicular groups, depending on the number of seg­
mental grafts, by removing the mesoneurium and epineu­
rium 1–2 cm from the end of the nerve (Fig. 24.11A). When
the distal stump of the recipient nerve has branches, each
nerve branch is separated. The segmental nerve graft is
placed between the appropriate nerve stumps (Fig. 24.11B),
and perineurial nerve suturing using 10-0 nylon is com­
menced (Fig. 24.11C). We prefer to suture first either side
of the nerve stump, which is difficult to rotate by manipula­
tion of the lateral suture because of limited mobilization of
the nerve. Following repair of the anterior aspect, the nerve
is turned over and the posterior aspect is repaired (Fig.
24.11D). Nerve repair is started from the most posterior
fascicular group and continued to the anterior one. At the
second site of the nerve repair, backward stitching tech­
nique is adapted whenever rotation of the nerve is not pos­
sible (Fig. 24.11E).
The stump of the recipient nerve is freshened as needed.
Holding the end of the graft and not grasping the nerve
with forceps, the needle is passed through the perineurium
of the graft using a small bite and continued through the
recipient nerve in the same fashion as perineurial suture.
The needle is carefully removed by following the curve of
Figure 24.9  Sural nerve anatomy. (A) The sural nerve courses in the posterior midline of the leg, (B) deep to the muscular fascia between the
heads of the gastrocnemius muscle. A relatively branch-free portion of the nerve is located in the proximal one-third to one-half of the nerve,
coursing near the gastrocnemius muscle. The nerve caliber increases from the popliteal crease (C) to the ankle more distally. (D) Multiple inci­
sion types can be used to harvest the nerve, and a nerve stripper may facilitate harvest. (E) The sural has both tibial and peroneal contributions,
and is seen branching from the tibial nerve.
B
C
D
E
Transverse
skin incisions
Common perineal
nerve
Sciatic nerve
Tibial nerve
Medial sural
cutaneous nerve
Lateral sural
cutaneous nerve
Lateral
malleolus
Sural
communicating
branch
Sural nerve
A
Figure 24.10  Preparation of sural nerve graft. (A) Removal of the
surrounding mesoneurium and fatty tissue. (B) The sural nerve is cut
into segments long enough to bridge the nerve gap.
A
B

CHAPTER 24 — Nerves
303
the same nerve or another target nerve. Finally, the distal
end of the second segment of the graft is connected to the
remaining fascicles of the donor nerve or to another donor
nerve if it exists. The standard technique of nerve repair is
epiperineurial suture for VNG when an ulnar or radial
nerve graft is utilized, and perineurial suture when a vascu­
larized sural nerve graft is utilized.
The advantages of nerve autografting include the ability
to reconstruct like with like, without the need for extensive
the needle, and the suture is tied in a manner, so as not to
overlap the ends of the nerve. The assistant holds the nerve
to prevent too snug an approximation. Following repair of
the anterior aspect, the nerve is turned over, and the poste­
rior aspect can be repaired. Four or five stitches are added
for each fascicular group in a similar fashion. When there
is a size discrepancy between the graft and the recipient
nerve, each individual fascicle can be separated to match
the size of the recipient nerve. Finally, the tension of the
nerve repair is examined by ranging the adjacent joints to
ensure that the graft remains quite loose, without undue
tension.
VASCULARIZED NERVE GRAFTING
The basic technique of nerve suture for a VNG is similar to
a conventional nerve graft; however, the nerve is repaired
sequentially from the proximal to the distal end of the
graft.98 Following vascular anastomoses of the nutrient
vessels, the proximal end of the graft is sutured to the recipi­
ent motor nerve. The nerve graft is then folded and divided.
This is done with care, so as not to injure the vascular
network supplying the nerve graft. The divided graft, which
now has two segments, proximal and distal, is then coapted
in the sequence noted in Figure 24.12. The proximal end
of the first segment is coapted to the donor motor nerve,
and the distal end of the proximal segment is coapted to
the recipient nerve. Then, the proximal end of the second
segment of the graft is sutured to the remaining fascicles of
Figure 24.11  Interfascicular nerve graft. (A) Removal of mesoneurium and epineurium of the recipient nerve. (B) Placement of a nerve graft.
(C) Suture of the anterior face at the first site. (D) Turn over and suture of the posterior face. (E) Backward stitching technique at the second
site.
A
C
D
E
B
Figure 24.12  Order of nerve suture for vascularized nerve graft:
1 → 2 → 3 → 4.
2
3
1
4

304
PART 3 — RECONSTRUCTION
technique must be discussed with patients as part of the
informed consent.
Nerve transfers have been facilitated by advancements in
understanding of internal neural topography. Intraopera­
tive electrical stimulation confirms function, lack of func­
tion, and redundancy prior to reconstruction. Donors for
nerve transfer are ideally purely motor or purely sensory
fascicles. Functional synergy of donor nerves to the recon­
structed function facilitates motor learning. Similar axon
number and an appropriate nerve size match are preferred.
Unlike tendon transfers, nerve transfers are appropriate in
the setting of joint stiffness, but motor donor function
should be a minimum of Medical Research Council (MRC)
grade 4.106 Multiple nerve transfers have been described and
are commonly used.17,77,83,107–110
END-TO-SIDE NERVE TRANSFERS
End-to-side (ETS) nerve transfer describes reinnervation of
an injured, or transected, recipient nerve via coaptation of
the end of the injured nerve into the side of an intact donor
nerve (Fig. 24.13A). This concept was described as early as
1895 by Ballance for treatment of facial paralysis,111 but did
not regain the clinical attention until the 1990s,112–117 with
both positive and negative results reported in subsequent
studies. The contradictory studies have resulted in persis­
tent controversy regarding this type of coaptation.
Techniques among surgeons and laboratories differ by
the presence or absence of an epineurial window at the ETS
coaptation. This difference is significant with respect to the
physiology of axonal regeneration across the coaptation.
“Regenerative sprouting” is a term describing axonal sprout­
ing in response to injury, while “spontaneous collateral
sprouting” refers to axonal sprouting in the absence of insti­
gating injury.118 Studies have shown improved or diminished
axonal regeneration across ETS coaptations in the presence
and absence of epineurial windows,114–116,119 implying the
ability of regenerating axons to penetrate neural connective
tissue layers, and in the presence or absence of associated
axonal injury.119,120 Some studies have shown evidence that
ETS nerve transfers result in collateral sprouting in sensory
nerves, but inducing sprouting in motor nerves only in
response the injury.121,122 Viterbo et al.114 showed no differ­
ence in quantities of regenerating axons after ETS coapta­
tion with and without an epineurial window, while others
Table 24.2  Comparison of nerve grafting versus nerve transfer
Degree of injury
Recovery
Rate of recovery
Surgical
management
Electrodiagnostic studies
I
Neurapraxia
Complete
Up to 12 weeks
−
No fibrillations
II
Axonotmesis
Partial +
1 mm daily
±
Fibrillations and MUPs
III
Axonotmesis
Partial
1 mm daily
±
Fibrillations and MUPs
IV
Neuroma-in-
continuity
None
None
+
Fibrillations, no MUPs
V
Neurotmesis
None
None
+
Fibrillations, no MUPs
VI
Mixed injury (I–V)
Some fascicles (II, III)
Varies with injury (I–V)
+
Varies with injury
postoperative motor re-education. Resulting movements are
spontaneous, and, as in the case of cross-facial nerve grafts
for facial nerve reconstruction, can have emotional inputs
as well. The disadvantages of nerve autografting include
the requirement of a donor site, two nerve coaptations
with resulting axonal drop-off, and potentially less robust
recovery. The nerve injury location may require a long
regenerative distance until target innervation, resulting in
disappointing functional results due to prolonged denerva­
tion, as previously discussed.29–34 In addition, the amount of
expendable donor nerve that is available may be limited,
and if proximal nerve ends are not present, such as in proxi­
mal brachial plexus avulsion injuries, nerve grafting is not
possible. The shortcomings of nerve grafting have inspired
development for additional reconstructive techniques, such
as nerve transfer. Nerve grafting is compared with nerve
transfer in Table 24.2.
NERVE TRANSFERS
Nerve transfers convert a proximal injury to a distal injury
by utilizing redundant, expendable innervation adjacent
to the end-target to address a specific functional deficit.
Reinnervation times are decreased, and functional out­
comes are therefore improved. Indications for nerve trans­
fer include proximal nerve injuries, unacceptable time for
regeneration (either due to distance to target or delayed
presentation), and scarring that would prohibit safe dissec­
tion at the zone of injury, such as in the case of critical
vascular grafts. Other advantages of nerve transfers include
avoidance of the need for an interpositional nerve graft,
avoidance of additional surgical sites, and potentially
stronger axonal input. Nerve transfers are possible when
a proximal nerve stump is unavailable, such as in bra­
chial plexus root avulsions, or loss of the facial nucleus
after oncological resection, or in cases with mixed (sixth-
degree) nerve injuries without downgrading function.
Conversely, motor re-education is a large part of postoper­
ative rehabilitation. Unwanted movements, such as smiling
while eating following a masseteric nerve to facial nerve
transfer for smile reconstruction, may persist postopera­
tively, either temporarily or permanently. In addition,
reconstructed movements may not be spontaneous or
emotional. The full advantages and disadvantages of this

CHAPTER 24 — Nerves
305
recovery of any favorable nerve injury, and the expendable,
healthy, donor nerve is transected and coapted ETS into the
intact recipient (Fig. 24.13B). The supercharge transfer
augments axonal input, allows recovery of injured native
nerve, and provides early muscle reinnervation as a “babysit­
ter” technique until regenerating native axons arrive at
target. The supercharge technique has demonstrated similar
axon regeneration and muscle mass preservation compared
with end-to-end repairs after complete, unfavorable (fourth-
and fifth-degree) nerve injuries134 and increased myelinated
axon counts, increased motoneuron counts, and improved
muscle-specific force testing in incomplete, favorable nerve
(second- and third-degree) injuries.135 Investigation of
reverse ETS sensory transfers for muscle protection are
ongoing.136
Functional outcomes of nerve transfers have been posi­
tive. A meta-analysis comparing nerve transfers to nerve
grafts for management of adult brachial plexus reconstruc­
tion showed improved functional results for elbow flexion
and shoulder function in the patients treated with nerve
transfers.137 After transfer of 2–3 intercostal nerves to the
musculocutaneous nerve for biceps reinnervation in patients
with birth-related brachial plexus palsy, Kawabata et al.138
reported 84% of the patients achieved M4 biceps strength.
Blaauw and Slooff139 described outcomes after a series of 25
patients had undergone medial pectoral nerve transfer to
the musculocutaneous nerve for restoration of biceps func­
tion in the setting of brachial plexus palsy. They noted
complete reinnervation of the biceps muscle in most cases
by 6 months after surgery. Over a mean follow-up of 70
months, 17 patients achieved excellent function and five
patients displayed fair function. There were two complete
failures due to disruption of the coaptation. They noted
their selection of the medial pectoral nerve due to its
increased number of motor fibers compared with intercos­
tal nerves. After a 4-month history of a severe ulnar nerve
deficit and intrinsic hand-wasting following failed ulnar
nerve transposition, successful revision of the ulnar nerve
transposition and augmentation with the RETS anterior
interosseous to ulnar motor nerve transfer was reported.134
At 12 months postoperatively, the patient recovered excel­
lent ulnar intrinsic function, which is unseen in revision
ulnar nerve transposition cases, as results are typically fair.
CONCLUSIONS
Management of peripheral nerve injuries has advanced tre­
mendously in recent decades, now with multiple operative
management strategies available to provide the most effec­
tive functional restoration for patients. Patient evaluation
and treatment center on nerve injury classification and
timing. Integral knowledge of nerve anatomy, physiology,
and regeneration provides the environment for continued
innovation in management of peripheral nerve injuries.
ACKNOWLEDGMENTS
Dr Snyder-Warwick thanks Dr Hywel Dafydd for assistance
with the references in the Historical notes and Andrew Yee,
for the design and preparation of Figures 24.3 and 24.13.
demonstrated enhanced neuroregeneration across the ETS
repair with an epineurial window.123 Creation of the epineu­
rial window itself may incite a small injury response.124
The ETS transfer has many clinical implications and
offers a reconstructive option when traditional techniques
are unavailable. ETS transfer has the advantage of no donor
morbidity from functional loss. The ETS transfer has been
used for restoration of non-critical sensation;125 reconstruc­
tion of donor sensory nerve deficits;126 brachial plexus
reconstruction;125 mixed nerve injuries; facial paralysis;127–129
and treatment of painful neuromas,130,131 particularly hyper­
algesia pain related to collateral sprouting from adjacent
sensory territories into the distal injured sensory nerve.132
Dellon et al.133 spotlight the confusion in terminology
with ETS repairs and suggest that traditional ETS repairs
consisting of an intact donor nerve be termed “side-to-end”
repairs to reflect the direction of neuroregeneration.
SUPERCHARGE (OR REVERSE END-TO-SIDE)
NERVE TRANSFERS
The supercharge nerve transfer, previously termed the
“reverse ETS (RETS)” transfer, is the opposite of the ETS;
the injured recipient nerve remains in continuity to allow
Figure 24.13  Schematic diagram for (A) end-to-side (ETS) nerve
transfer, and (B) supercharge or reverse end-to-side (RETS) nerve
transfer. Blue nerves represent donors, while the purple nerves are
the recipients.
Donor
Donor
Recipient
Recipient
B
A

306
PART 3 — RECONSTRUCTION
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Expert Commentaries
Ivica Ducic, MD, PhD
Authors present a very nice outline on nerve injury, regeneration
and repair options. As every microsurgeon pays great attention
to microvascular anastomosis details, we learned that anasto-
mosis itself is only a part of the entire reconstructive process,
since the choices of flap, orientation, insert and functional dura-
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substantial amount of research over the last few decades was
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microscope or loops enable equal results and what size of
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Along this process, and with the evolution of evidence-based
medicine, attention to other than nerve anastomosis type
details has contributed the most in the advancement of nerve
reconstruction over the last few decades. Thus, we learned that
the tension inversely affects both arterial and venous flow at
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across the gap. This gap size induced problem, when attempt-
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concerns for up to several centimeters wide gaps. Similarly, as
misalignment with primary repair leads to reconstructive fail-
ures and potential neuroma in continuity pain, usage of nerve
connectors was developed to help overcome this problem,
when appropriate. Failures with proximal nerve injury repair
contributed to the development of nerve transfers, offering
promising solution for many brachial plexus and proximal nerve
injuries. Aside from ideal immediate nerve repair, when select-
ing reconstructive technique, one should remember that the
time for reconstructed nerve to reach the target organ is based
on the location of nerve injury, its distance to the target tissue
and the prorated time for regenerating nerve to reach target
organ from injury time, not reconstruction time. Equally impor-
tant is also the attention to proper proximal/distal resection of
damaged nerve, as only healthy fascicles will enable regenera-
tion of reconstructed nerve.
Thus, as the nerve regenerative science continues to evolve,
consideration of all aforementioned variables, individually tai-
lored to patient’s specific presentation should enable best pos-
sible outcome.
Huan Wang, MD, PhD and Robert J. Spinner, MD
Autologous nerve graft remains the clinical gold standard for
repairing segmental nerve defects. Due to the limited availability
of donor tissue and the morbidity associated with autologous
nerve grafting, scientists are exploring the efficacy, applicability
and marketability of ready-to-use, off-the-shelf alternatives.
Since the first application of a bone tube as a nerve conduit in
1879, neural tissue engineering research is increasing its foot-
print in the development of bioartificial nerve guidance conduits
as an alternative treatment.
The factors that control material selection for nerve conduits
include biocompatibility, biodegradability, mechanical integrity,
controllability in implantation, and sterilization. The FDA-
approved, clinically used nerve guides are collagen-based
conduits, polyglycolic acid (PGA) conduits and poly(DL-
lactide-ε-caprolactone) (PLC) conduits. These nerve tubes are
indicated for primary or secondary repair of nerve defects up
to 3 cm. Many are using them to repair sensory nerves, espe-
cially digital nerves. Some are utilizing them in repairing mixed
motor/sensory nerves, even major nerves with larger gaps. The
sensory outcomes, judged by two-point discrimination, can be
rated as good to excellent in 75% of the digital nerves that are
repaired by these resorbable conduits. Nerve conduit implanta-
tion needs a vascularized tissue bed and good soft tissue
coverage. Caution should also be taken when implanting nerve
guides near a joint. Protrusion of nerve conduits has been
reported after the use of synthetic polymer conduits.
Processed human nerve allograft has been utilized for repair-
ing defects up to 5 cm of nerves in the extremities, as well as
defects up to 7 cm in sensory branches of the trigeminal nerve.
Its use is still predominantly in digital nerves, meaningful recov-
ery has been reported in mixed nerves or motor nerves. Source,
storage and transportation, and risk of viral transmission are
among the challenges of allograft application.
Thus far, similar results rather than superiority have been
achieved comparing nerve conduits, allograft and autograft in
many experimental studies and some clinical trials. Realistically,
there is still a long way to go for bioartificial nerve conduits or
processed allografts to replace autologous nerve graft as main-
stream nerve repair strategy, especially for large defects or for
nerves of critical functions. A combination product, a scaffold
that mimics the microarchitecture and mechanical properties
of a natural nerve and supplemented with autologous cells that
exert neurotrophic factors in a controllable fashion, may provide
the key to achieving desired regeneration and functional recov-
ery. The race is on. This is an exciting time for research in
peripheral nerve regeneration.

CHAPTER 24 — Nerves
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concepts. J Hand Surg [Am] 2010;35(3):491–7.
85. Grinsell D, Keating CP. Peripheral nerve reconstruction after
injury: a review of clinical and experimental therapies. Biomed
Res Int 2014;2014:698256.
86. Brushart TM, Seiler WA 4th. Selective reinnervation of distal
motor stumps by peripheral motor axons. Exp Neurol 1987;97(2):
289–300.
87. Nichols CM, Brenner MJ, Fox IK, et al. Effects of motor versus
sensory nerve grafts on peripheral nerve regeneration. Exp
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88. Brenner MJ, Hess JR, Myckatyn TM, et al. Repair of motor nerve
gaps with sensory nerve inhibits regeneration in rats. Laryngo­
scope 2006;116(9):1685–92.
89. Moradzadeh A, Borschel GH, Luciano JP, et al. The impact of
motor and sensory nerve architecture on nerve regeneration. Exp
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90. Iorio ML, Felder JM III, Ducic I. Anterior branch of the obturator
nerve: A novel motor autograft for complex peripheral nerve
reconstruction. Ann Plast Surg 2011;67:260–2.
91. Brushart TM. Preferential reinnervation of motor nerves by
regenerating motor axons. J Neurosci 1988;8:1026–31.
92. Kawamura DH, Johnson PJ, Moore AM, et al. Matching of motor-
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neurectomy: a long-term evaluation in the rat model. Microsur­
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120. Viterbo F, Amr AH, Stipp EJ, et al. End-to-side neurorrhaphy: past,
present, and future. Plast Reconstr Surg 2009;124:351e–358e.
121. Brenner MJ, Dvali L, Hunter DA, et al. Motor neuron regenera­
tion through end-to-side repairs is a function of donor nerve
axotomy. Plast Reconstr Surg 2007;120(1):215–23.
122. Hayashi A, Pannucci C, Moradzadeh A, et al. Axotomy or com­
pression is required for axonal sprouting following end-to-side
neurorrhaphy. Exp Neurol 2008;211(2):539–50.
123. Kovacic U, Zele T, Tomsic M, et al. Influence of breaching the
connective sheaths of the donor nerve on its myelinated sensory
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the rat. J Neurotrauma 2012;29(18):2805–15.
124. Haninec P, Kaiser R, Dubovy P. A comparison of collateral sprout­
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125. Tos P, Colzani G, Ciclamini D, et al. Clinical applications of end-
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126. Viterbo F, Palhares A, Franciosi LF. Restoration of sensitivity after
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127. Scaramella L. L’anastomosi tra I due nervi faciali. Arch Otolaryn­
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128. Viterbo F. A new method for treatment of facial palsy: the cross-
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129. Beutner D, Luers JC, Grosheva M. 2013. Hypoglossal-facial-jump-
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130. Al-Qattan MM. Prevention and treatment of painful neuromas of
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131. Aszmann OC, Moser V, Frey M. Treatment of painful neuromas
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133. Dellon AL, Ferreira MC, Williams EH, et al. Which end is up?
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135. Farber SJ, Glaus SW, Moore AM, et al. Supercharge nerve transfer
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137. Garg R, Merrell GA, Hillstrom HJ, et al. Comparison of nerve
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138. Kawabata H, Shibata T, Matsui Y, et al. Use of intercostal nerves
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surgery 2003;53(2):338–41.

310
INTRODUCTION
It is more than a century since Alexis Carrel introduced the
techniques of vessel repair in 1906. The triangulation tech­
nique founded by him was used for the repair of major
vessels. The origin of modern microvascular practice is cred­
ited to Jacobson and Suarez, who borrowed the use of the
operating microscope from their otolaryngology colleagues
in the 1950s.1 With time, the diameter of the vessels anasto­
mosed has become smaller. Achieving over 98% patency
rates in the anastomosis of vessels of 1 mm in diameter is
now common. In many units, surgeons have perfected tech­
niques to regularly repair vessels as small as 0.5 mm in diam­
eter. This has come to be called “supermicrosurgery.”2 It has
been made possible due to the excellent optics in present-
day microscopes, improved design of microsurgical instru­
ments, availability of fine microsutures, and the stress on
laboratory training by early pioneers, such as Acland.3
Current research in microsurgery has shifted to designing
new flaps and refining existing ones. But no matter where
the advances lead, ultimate clinical success in microsurgery
will depend on good technical skill in vessel anastomosis.
Hence, the contents of this chapter are important. We are
dealing with maneuvers where the margin for error is low.
Strict adherence to basic rules during vessel preparation
and actual suturing skills will ever remain the cornerstone
for good microsurgical work.
PREPARATION OF RECIPIENT VESSELS
SELECTION OF RECIPIENT VESSELS
The location and length of the recipient vessels will be fac­
tored into the design and size of the flap. While this step is
important for every flap, in some situations, such as the
lower leg, it is so important that free flap surgery of the
lower leg is considered to be the surgery of dissecting
the recipient vessels. Recipient vessels should be away from
the zone of trauma and sites of irradiation. In limb surgery,
on rare occasions, recipient vessels are chosen distal to the
zone of trauma.4,5 While success has been reported, this
should be resorted to only when the proximal side is not
available. If possible, the vessel is selected away from the
joints, since around the joints the arteries have more
branches and there is a valve in the vein where every tribu­
tary joins.
Exposure must be adequate to access a good length of
recipient vessel. The length dissected depends upon the
depth at which the vessel is situated, the size of the vessel,
and the technique of anastomosis to be employed. The
deeper the plane of the vessel, the greater the length of
vessel that needs to be dissected for ease of maneuverability.
If single clamps are used during anastomosis, it is sufficient
to dissect a short length of vessel. If double clamps are used,
a minimum length equal to five times the diameter of the
vessel needs to be dissected on either side, for ease of appli­
cation of clamps and turning the vessel to suture the back
wall. The surgeon should operate with good technique,
always handling the vessels by holding the adventitia and
never by grasping the wall directly with forceps.
CHOOSING THE SITE OF ANASTOMOSIS
The site of anastomosis is chosen away from branches and
away from venous valves. As a rough guide, it is preferable
to avoid them within the segment of the vessel that will be
included in the clamp. If there is an arterial branch very
close to the site of anastomosis, it is better to divide it
because:
• The arterial ends retract after division and if there is any
undivided branch close by, it may act as a tethering
restraint and cause a kink.
• It makes clamp application and turning the vessel to
suture the back wall difficult.
• It may act as a restraint in positioning the pedicle prior
to wound closure.
Division of venous tributaries close to the anastomosis
might also be useful in some situations. If two or three
branches of the artery or vein have been ligated near the
site of anastomosis, it is better to trim the vessel proximal
to this region in order to avoid turbulence near the site of
anastomosis.
GROSS TRIMMING OF THE ADVENTITIA
One need not strip the whole length of the vessel. Prior to
applying the vessel clamp, gross trimming of the adventitia
using sharp adventitia scissors is performed in the area of
the proposed anastomosis and in the area where the clamp
is to be applied. Trimming prior to vessel division is easier
to perform and allows for the vessel clamp to work more
effectively without slipping. Fine trimming is performed
Vessels
S. Raja Sabapathy
25 
PART 3  —  RECONSTRUCTION
SECTION A  —  MICROSURGERY TECHNIQUES

CHAPTER 25 — Vessels
311
should be anastomosed in the regular manner. Backflow
from the radial artery, facial artery, and superior thyroid
artery have all been utilized successfully. On a few occasions,
we have used the distal arterial segment to perfuse flaps in
the lower leg without problems. This is recommended only
in exceptional circumstances and not as the preferred
option. During and after dissection, the vessels are bathed
in warm irrigating solution (around 37°C), prepared by
adding 20 mL of plain lidocaine and 2000 units of heparin
to 200 mL of Ringer’s lactate. We use 2% plain lidocaine
irrigation to prevent spasm of the vessels. Higher concentra­
tions of lidocaine are more potent in experimental situa­
tions, but clinically we have found that 2% lidocaine is also
effective. If the vessel does go into spasm, one should avoid
handling the vessel; keep lidocaine- or papaverine- (3%)
soaked gauze pieces over the area and flood the field with
warm irrigating solution. The surgeon should avoid the
temptation of frequent inspection and handling of the
vessel. Usually, the spasm clears in about 5 min. When
the vessel is in spasm, recognize the problem and avoid
cutting the vessel end proximally in search of good flow.
The cut end will still be in spasm and one may end up losing
valuable length of the vessel. Excess manipulation will make
things worse and patience is the key. Topical vasodilators,
when used, must not be infused into the vessels. Soaked
lidocaine gauze pieces are also irrigated with warm saline.
Because of this irrigation and washing out, the chances of
systemic problems are negligible.
MANAGEMENT OF FLAP VESSELS
The length of the flap pedicle dissected depends upon flap
anatomy and the recipient vessel diameter. In elective flap
surgery, proper planning usually obviates the need to use
vein grafts. The diameter of the vessels becomes larger as
the flap vessels are dissected more proximally. One only
needs to dissect until an appropriate length and reasonable
match of vessel size occur. For example, if one is performing
a latissimus dorsi muscle flap to the lower leg, it is sufficient
to dissect up to the take-off of the thoracodorsal artery after
the subscapular gives off the circumflex scapular and not go
further. The size match between the thoracodorsal vessels
and the tibial vessels and between the venae comitantes is
reasonable. Further dissection only accentuates the size dif­
ference between the veins. The same principle is followed
in dissecting perforator flaps.
It is not necessary to skeletonize the whole length of the
pedicle. If the pedicle is to be tunneled beneath the skin,
for example in toe transfers where one tunnels beneath the
dorsal hand skin to reach the recipient vessels in the snuff
box or wrist, the vessels are dissected free of excess soft
tissue over a greater distance. Otherwise, a short-segment
skeletonization of 2 cm is sufficient. An end-to-side anasto­
mosis demands a relatively longer length of flap vessel than
an end-to-end anastomosis, for ease of handling during
suturing of the back wall.
At the end of flap dissection, leave the flap perfused for
about 15–20 min. The flap vessels are not handled during
this time and are bathed with warm irrigating solution and
2% plain lidocaine. Spasm is relieved and equilibration of
flow dynamics occurs in the flap. If the vessel is divided
after division and placement of the vessels within the clamp
and is described later in the chapter.
ASSESSING THE QUALITY OF THE
RECIPIENT VEIN AND ARTERY
RECIPIENT VEIN
Large recipient veins that are at least as large as the flap vein
or larger (up to twice as large) are ideal. A single or double
clamp is applied and the vein is divided. If there is any doubt
about the quality of the vein, the vein is flushed with dilute
heparinized saline using a 5 cc syringe with a blunt small
catheter, in order to assess the ease of drainage. This is
judged by feel and, as a general rule, the syringe should
flush smoothly and with minimal pressure. If upon division
of the vein, a large amount of backflow appears, this is not
necessarily a contraindication to utilizing that vein. High
pressure might cause resistance to venous drainage of the
flap and, in such situations, tying off one or more tributaries
that drain to the vein near the anastomosis might help to
reduce the backflow. In other words, what might appear as
high flow from the vein after division does not affect the
patency of the anastomosis provided that, when flushing the
vein using a 5 cc syringe, the flow is without significant
resistance. We do not have a clear guideline by which to
judge whether the pressure is truly too much. But whenever
we feel that there is a high backflow, particularly in lower
extremity reconstructions, we make a point of keeping the
leg elevated over two pillows, at least to the heart level, when
the patient is lying down during the postoperative period.
RECIPIENT ARTERY
After vessel dissection, good expansile pulsation of the
recipient artery and clear flow in the recipient veins, as seen
under the microscope are adequate to proceed with flap
dissection. If in doubt, a single or double clamp is placed
on the artery, the artery is sectioned, and flow is confirmed.
With normal pressure maintained and no evidence of
spasm, the blood should be spurting from the artery for it
to be considered a good recipient vessel. This step is not
required in elective free flap transfer but may be required
while performing emergency free flaps and replantations.
When this step is performed, the surgeon should be aware
of the length of time the clamp has been placed on the
vessel prior to the anastomosis. If vessel length is not an
issue, we favor the use of a clip at the end of the vessel after
the testing procedure, or trimming the part of the vessel
where the clamp was placed. The patient should be main­
taining their normal blood pressure when flow in the recipi­
ent vessels is being tested. Good-quality clamps when applied
for up to 30 min have not been found to cause increased
incidence of thrombosis, but clamp application for more
than 60 min should be avoided.6 On rare occasions, the
arterial backflow may be stronger than the antegrade flow.
The scenario will be a good pulsatile vessel, which on divi­
sion reveals a jet of flow from the distal end and a thin
stream of flow from the proximal end. If spasm of the vessel
is excluded as the cause for the poor antegrade flow, then
the distal end could be used to supply the flap. The veins

312
PART 3 — RECONSTRUCTION
prudent to re-check the status of the recipient vessels just
before division of the flap vessels. The mucosa of free jejunal
flaps and free functioning muscle transfers do not withstand
long ischemia times compared with pure skin flaps or bone
flaps. Hence, it is better to keep the flap perfused until the
recipient site is ready for transfer.
MICROSURGICAL INSTRUMENTS
Only a few instruments are needed for regular microsurgi­
cal work, but they must be of high quality (Fig. 25.1). It is
preferable that a surgeon always uses the same set so that
there is familiarity with the feel of the instruments. A set of
jeweler’s forceps, vessel dilator, scissors, needle holders,
appropriate vessel clamps, and clamp applicator forceps
comprise the basic set. The tips of the forceps must be
aligned with a precision of 1/1000 inch, since that is the
diameter of the 10/0 nylon suture. When closed with mod­
erate pressure, the jaws should meet not only at the tips but
also evenly over a length of 3 mm, so that the thread can be
picked up easily. We find Pierse forceps, distinguished by
when it is in spasm, after anastomosis it will also be in spasm.
During pedicle division, the flap artery is clamped before
the vein. If the vein is clamped first, the continuing inflow
causes the flap vein to bulge, which may cause a severe vessel
size discrepancy. Perfusion of the dissected flap with pre­
pared tissue preservation solutions is never necessary prior
to transfer.
It is not clear whether the blood within the flap is drained
or not after flap harvest. We have always cut both the artery
and the vein and allowed the blood to drain out and have
not noticed any problem utilizing this method. Marking the
artery and vein may not be necessary in most cases, the veins
being thinner and more pliable and the presence of valves
and communicating branches between the two venae comi­
tantes being characteristic markers. But for the beginner
and in certain flaps, such as the lateral arm flap, where the
difference is less clear, it may be useful to mark the vessels
by either vascular clip or suture. Whatever system is used,
the same must be followed by every member of the team at
all times to prevent confusion.
The flap vessels are divided only when everything is ready
at the recipient site, to minimize the ischemia time. It is
Figure 25.1  A selection of microsurgical instruments.
Clamp applying
forceps (CAF-4)
B-2V
B-3V
RD-3
RD-D
Needle-holders
(B-13-10)
Dissecting
scissors
(SDC-11)
Adventitia
scissors
(SAS-11)
HD-D
JF-3
JF-3
Vessel dilator
(D-5a)
Big toothed
jeweler’s
forceps
Pierse
forceps
JFP-3
Dissecting scissors
(SDC-15T)
Adventitia scissors
(SAS-15)
ABB-3V
ABB-2V
ABB-1V

CHAPTER 25 — Vessels
313
round body, flattened in the middle to improve stability in
the needle holder. Standard needles are 50 µm and 70 µm
in size. They are honed under the microscope and the
needle to thread attachment is rigidly tested to avoid break­
age during use. Choice of suture material depends upon the
diameter and thickness of the vessel wall. Thinner sutures
create finer-looking repairs but a greater number of sutures
are needed. Thick-walled vessels need more solid needles
and thicker sutures. As a general guide, use 9.0 sutures for
vessels of ≥2 mm in diameter, 10.0 sutures for vessels of
1–2 mm, and finer sutures for vessels of lesser diameter.
COAPTATION DEVICES
Attempts to find a safe and easy non-suture technique of
microvascular anastomosis have been in progress for more
than three decades. Non-suture techniques can be catego­
rized into five groups based on the materials used: ring
coupling devices, clips, adhesives, stents, and laser welding.
The most successful is the microvascular coupler system
(Fig. 25.3). The coupler device has rings that consist of
1–4 mm diameter in two equally-sized opposing rings, into
which six pins are machined, with the pins being of 0.16 mm
shaft diameter in the small ring. Each end of the vessel is
fed through the center of an appropriately sized ring, the
vessel ends are a ring and everted 90°, and then impaled on
small pins, which pass from the outer to the inner surface
of the vessel over each pin in turn. This is achieved using
specially designed forceps, which allow passage of the pin
through a small hole in the tip, while pressing the everted
vessel wall down onto the ring. Closing the coupler device
brings the two rings into opposition, so that each set of pins
becomes seated into the opposite ring, bringing “clamping”
of the inner surfaces of the two vessel ends together.
The coupler technique involves preparing the vessel ends
as described earlier. A special sizer is used to measure the
lumen diameter of each vessel. Seven sizes of coupler are
available, from 1.0 mm to 4.0 mm, with increments of
0.5 mm. When there is a discrepancy in the size of the two
lumens, the smaller of the two is used to select coupler size.
Up to a 3 : 1 discrepancy in size can be accommodated in
this way. The coupler devices are intended for vessels with
an outside diameter of 0.8–4.3 mm, with a wall thickness of
≤0.5 mm. As with hand-sutured anastomoses, it is important
to pay attention to the orientation of the vessels to prevent
kinking. It is also helpful to fix the coupler to the longer,
or more mobile vessel first, as this makes passage of the
second vessel through its ring easier. Care must be taken not
to exert excessive traction on the vessels while maneuvering
the coupler device. Once both vessel ends are everted over
the pins, the coupler is closed by turning the handle. A final
squeeze is applied with a hemostat to ensure closure, before
carefully retracting the device.7
Compared with the “gold standard” of small vessel anas­
tomosis with 10.0 sutures, many studies have proven that
anastomoses by coupler devices are completed 4–5 times
faster, with patency rates approaching 100%. The strength
of the anastomosis is also good and it is especially useful for
anastomoses in deep wounds with difficult access. It is a little
more difficult to do in thicker arteries or atherosclerotic
vessels, since eversion is difficult. Coupler devices are best
Figure 25.2  Pierse forceps with a minute hole in the tip, useful to
hold adventitia.
their minute “hole in the tip” (Fig. 25.2), remarkably useful
for holding the adventitia during general vessel preparation
steps. The vessel dilator is a modified jeweler’s forceps with
a slender, smoothly polished, non-tapering tip. It is designed
for controlled intraluminal vessel dilatation but many use it
also as a counter pressor during suturing and for tying the
knots. The 10° angulated vessel dilator forceps is generally
used. The scissors are of two types: the dissecting scissors
have curved blades with the tips rounded at the point with
a radius of 0.3 mm – they are safe for dissection; the adven­
titia scissors have straight blades pointed at the tip for fine
trimming at high magnification – it is not advisable to use
adventitia scissors for blood vessel dissection, since their
sharp points pose a real danger of puncturing the vessel
wall. Pick a needle holder with slender curved jaws, which
permit the handling of the smallest needles and the easy
tying of the knots with fine thread.
Instruments of 12 cm in length are generally used.
Smaller ones can only be used on the surface. The deeper
the work that needs to be done, the longer the instruments
that are required. Spring tension of the instruments is
important. There must be a balance between strong tension,
which causes fatigue of the thenar muscles, and weak
tension, which causes the instruments to slip from the hand.
To test the spring of an instrument for weakness, Acland
advises the surgeon to pick it up and hold it with just enough
force that the limbs are 1–2 mm apart. Then, maintaining
just that force, pronate the forearm completely so that the
instrument hangs upside down. If it falls away from the
hand, the spring is too weak. To test for excessive firmness,
hold the instrument gently closed for 10 min. If one feels
pain in the thenar muscles, the spring is too strong. The
spring tension must lie between these two extremes. Locking
instruments are no longer used.
SUTURE MATERIAL
Sutures for microvascular surgery are now exclusively made
of nylon or polypropylene and are available in the range of
8.0–12.0. Only rarely are the finer sutures beyond 10.0 used
in free flap surgery. They find their use mostly in very distal
fingertip replantations, in small children, and in lymph
vessel anastomoses. The needles are of a taper point with a

314
PART 3 — RECONSTRUCTION
can be used to anastomose onto the internal jugular vein.11,12
A coupler may also be useful for anastomoses in deep
wounds with difficult access. In future, the frequency of
usage of ring pin couplers, clips, and other non-suture tech­
niques will increase, but suturing will still be needed for
vessels with severe atherosclerosis and in circumstances
where vessel edges are difficult to evert.
The literature is sparse in articles dealing with the use of
couplers with atherosclerosis and with size discrepancy.
Draper and colleagues, in a large series of breast reconstruc­
tions (47 TRAM and 22 DIEP), had a high rate of success
but in optimal conditions of artery and of caliber.13
VESSEL SET-UP FOR SUTURING
If the two ends of the vessels to be sutured are kept well
approximated without tension and the pedicle lies without
kinking, the stage is set for success. The actual maneuver of
suturing then becomes a simple exercise. It is important to
choose the correct clamp size for the vessels. Clamps for
microsurgery come in five sizes: B-1, B-2, B-3, HD, and RD,
with a suffix V or A attached to each. Thus in each category,
we will have two clamps (e.g., B-1V and B-1A). The clamps
with code V are not designated solely for veins, but are used
as the general-purpose clamp for application to all veins and
practically all arteries. The A pattern is used for exception­
ally thick-walled and slippery arteries. The slight incurve of
the tips of the A pattern jaw gives extra security against slip­
page. If, when applying a V clamp, the vessel slips out, an A
clamp can be used. Clamps may also slip if the adventitial
stripping is inadequate or inappropriate smaller clamps are
used. The clamps are available in two finishes, black or
plain, with the black being preferred to avoid glare from the
bright microscope light.
Closing pressure is an important consideration when
choosing the clamp. The pressure is determined by the
closing force of the clamp (in grams, g) divided by the area
of the vessel wall that is compressed between the jaws (in
square millimeters, mm2). Thus, the pressure is inversely
proportional to the vessel size. The smaller the vessel inside
the clamp, the higher the pressure. A good-quality clamp
exerts a pressure of 5–10 g/mm2 when used on the largest
vessel in its size range, and 15–20 g/mm2 when used on the
smallest recommended vessel. There is a 50% overlap in
the recommended vessel diameter range between each
clamp size and the next larger or smaller (Fig. 25.4). Thus,
for any exact vessel diameter, there will always be two suit­
able clamps. The smaller clamp is preferred whenever
possible.
The vessel ends are prepared by stripping the adventitia
up to the area that would be in the clamps. Double clamps
are applied (single clamps may be used during this step).
While applying the clamp, care is taken not to snap the
clamp onto the vessel, which can occur when the clamp
applier slips during the application process. A moist sponge
is placed beneath the vessel set-up in order to elevate the
plane of the anastomosis and to provide a space for fluid to
collect before reaching the plane of the anastomosis and
interfering with the field. Background material is placed
beneath the clamp and vessels. Fine trimming is performed
to clearly see the vessel ends while suturing, and to prevent
suited for minimally discrepant, soft, pliable venous micro­
vascular anastomoses, though now it is being advocated
even for veins with a 3 : 1 discrepancy in size. The coupler is
less suited to thicker arteries or atherosclerotic vessels, since
eversion is difficult.8,9
The technique involves preparing the vessel ends, as
described earlier. The MCA microvascular sizer is used to
measure the lumen diameter, while the vessel is being
dilated with the vessel dilator. There are five sizes, from
1.0 mm to 3.0 mm, with increments of 0.5 mm. When there
is discrepancy of the vessel lumen, the use of the coupler
size is equivalent to that diameter measured on the smaller
vessel. Couplers have also been used for arteries, but their
use is better restricted to good vessel conditions.10
The coupler has been described for use in an end-to-side
anastomosis, particularly in head and neck surgery, where it
Figure 25.3  Microvascular coupler system. (A) The coupler
device. The vessel is brought in the ring and impaled over the sharp
pins with the intima facing each other. (B) The coupler device closes
with each set of pins seated into the opposite ring bringing, the intimal
surfaces together. (C) The anastomosed vessel removed from the
coupler device.
B
C
A

CHAPTER 25 — Vessels
315
the open end must be flushed out. Blood in undamaged
vessels not in contact with wound thromboplastins does not
clot and hence, special precautions are not needed for the
blood in the vessels beyond the clamps.
The final step before starting the anastomosis is to ensure
good hemostasis in the vicinity. A continuous trickle of
blood obstructing the working field can lead to disaster. Ask
the assistant to keep the immediate field void of blood by
frequently irrigating the field, as the blood may stick to the
vessel wall and be difficult to remove after forming a fibrin
clot.
The clamp and vessels are positioned so that the surgeon
is comfortable performing the anastomosis. This position
should be oriented parallel to the surgeon. Both vessel
lumens should be in the same plane and clearly in view. If
the above criteria are not met, the surgeon must change the
position of the clamp by elevating or rotating it, or changing
the position of the extremity, the table, the microscope, or
his or her own position.
Four moistened gauzes are placed around the field of
anastomosis to avoid having the suture stick to surrounding
structures.
SUTURING TECHNIQUES
END-TO-END ANASTOMOSIS
The most common suture technique is the end-to-end anas­
tomosis. If the vessel sizes are of reasonable match, a simple
triangulation technique is used to place interrupted sutures.
In the triangulation technique, the first suture can be taken
at the place where it is comfortable. The second suture is
taken one-third of the distance or 120° from the first. When
these two stay sutures are tensioned, the two front edges
come together and the back edges hang down. The second
bite of the second suture is the most important step and it
must be taken with the greatest care, such that both the
entry and the exit points lie at equal distances from the site
of the first suture (Fig. 25.5). Sutures are placed in between
the stay sutures and the approximator clamp is turned over.
The long back edge will be in view. The first suture is placed
on the back edge exactly midway between the two existing
stay sutures. This divides the remaining unsutured part of
the vessel’s circumference into two equal halves. By holding
on to the stay sutures, the anastomosis is completed. It is
crucial to avoid a “through stitch” in which both walls are
caught by the suture. This is avoided by observing the tip of
the adventitia from getting caught in the lumen while tying
the knot. Adventitia inside the anastomosis can induce
thrombus formation. This technique is performed under
high magnification and for a distance of 3–4 mm away from
the anastomotic site. Gross trimming is performed more
proximally to avoid sticking of the sutures during the tying
process.
After irrigation of the vessels, the vessel dilator is cleaned
and moistened with heparinized saline, inserted into the
vessel lumen, and used to gently dilate the vessel in two
planes, to about one and a half times the normal diameter.
This eases suturing and may also help in preventing the
vessel from going into spasm. The double clamps are
approximated until the vessel ends just touch each other.
There must be neither tension at the suture line nor vessel
redundancy. Blood in the lumen beyond the clamps toward
Figure 25.5  (A–C)The second half of the second suture must be taken so that both the entry and the exit points are equidistant from the first
suture.
A
B
C
Figure 25.4  Graph showing the relationship between clamp size,
recommended vessel diameter and clamp pressure. Vessel diameter
refers to the external diameter of the vessel in its natural state of full
dilatation.
B-3
HD
B-2
B-1
RD
15
10
5
Clamp pressure
(g/mm2)
Recommended
vessel diameter
(mm)
1
2
3
4
5