Flaps Practical Reconstructive Surgery

228
II Reconstructive Flaps A-to-Z
limb reconstruction. Bashir (1983) reports successful use of the
reverse medial gastrocnemius ap for closure of defects of the
lower third of the leg, through the preservation of the most dis-
tal communicating branches between the two heads, although
we would not recommend this as the proximal pedicle is the
dominant vascular supply. The ap can be taken with a skin
paddle but this often results in a particularly bulky ap and an
unsightly donor site and so a skin graft is usually preferred. A
vacuum -assisted closure (VAC) device can be used to secure the
skin graft without compromising the muscle ap. Denervation
of the ap has been described to reduce the muscle bulk but this
is not necessary as division of the insertion and transposition
defunctions the muscle, with subsequent atrophy.

Hints and Tips

●
Ensure exam ination of the patient clinically preoperatively;
some patients have a short muscle belly w ith a long

Clinical Perspectives
The m ain application is in the reconstruction of lower extrem ity
soft tissue defects in the upper tibial and knee region (Fig. 18.6).
The ap only covers the inferior half of the knee joint and hence
is not suitable for covering high knee defects.

Flap Variations
To increase the reach of the ap, Arnold (1983) described divid-
ing the origin from the condyle of the fem ur and scoring of the
muscle fascia for extra length. Avoid extending the incision in a
straight line across the popliteal fossa to prevent scar contracture
formation. It is also important to avoid traction on the pedicle if
the origin is detached. Unusual variations of the gastrocnem ius
are the use as a free ap with interposition grafts to lengthen the
pedicle. It has also been used for functional transfers in upper
Fig. 18.2 Care is taken to identify and protect the sural nerve shown between
the heads of the gastrocnemius muscle and the short saphenous vein, which
can be seen in the subcutaneous tissue in the lower skin ap.
Fig. 18.3 The two heads of the gastrocnemius muscle are separated
along the raphe by sharp dissection.
Fig. 18.5 The medial head of the muscle is passed through a subcutane-
ous tunnel to cover the defect.
Fig. 18.4 A distal cu of the tendinous portion as it merges with that of
the soleus to form the Achilles tendon is taken along with the medial head
of the muscle to assist in the inset. The muscle belly is now attached only
at its proximal origin and by the pedicle.

18 Gastrocnemius Muscle Flaps for Lower Limb Reconstruction
229
Suggested Further Reading
Arnold PG, Mixter RC. Making the most of gastrocnem ius muscles. Plast
Reconstr Surg 1983;72:38
Bashir AH. Inferiorly-based gastrocnem ius muscle ap in the treatment
of war wounds of the m iddle and lower third of the leg. Br J Plast
Surg 1983;36:307
Ger R. The technique in muscle transposition in the operative treat-
m ent of traumatic and ulcerative lesions of the lower leg. J Trauma
1971;11:503–510
Keller A, Allen R, Shaw W. The medial gastrocnemius m uscle ap: A local
free ap. Plast Reconstr Surg 1984;73:974
Potparic Z, Colen LB, Socur D, CArwell GR, Carraway JH. The gastrocnemius
m uscle as a free ap donor site. Plast Reconstr Surg 1995;95:1245
Figure Credits
1. Strauch B, Yu HL. Atlas of Microvascular Surgery: Anatomy and Oper-
ative Approaches. 2nd ed. New York, NY: Thieme; 2006
tendinous portion that may not provide enough tissue
cover, in which case an alternative ap will be required.

●
Most defects can be covered using the m edial head, which
is larger and avoids the risk of iatrogenic damage to the
com m on peroneal nerve which passes between the lateral
head and the tendon of biceps femoris. The case illustrated
above covered a defect to the anterolateral knee without
having to either detach the origin or score the fascia.
The latter rarely results in improved coverage. High knee
defects are best covered with alternative aps such as a
saphenous fasciocutaneous ap.

●
We would not recom mend simultaneous use of both the
medial and lateral heads due to the functional de cit.
Sacri ce of a single head does not result in a signi cant
functional impairment of gait in the majority of individuals.
a
Fig. 18.6 Clinical application for a gastrocnemius ap. (a) A full-thickness defect of the left knee with an exposed lateral ligament reconstruction.
(b) A full-thickness defect of the left knee reconstructed with a medial gastrocnemius ap and split-thickness skin graft.

230
Gracilis Muscle and Myocutaneous Flaps
Cedric Hunter, Gordon K. Lee, and Michael W. Findlay
19

Classif cation

●
Mathes-Nahai—type II
a. Dom inant vascular pedicle: term inal branch of m edial
femoral circum ex artery
b. Minor vascular pedicle(s): distal branches from super -
cial femoral artery

Vascular Pedicle
Dominant and Minor Pedicles
The gracilis m uscle is supplied on its deep surface by two to ve
pedicles. The most consistent and main vascular pedicle arises
from the medial femoral circum ex vessels and is accompanied
by paired venae comitantes. In approximately 10% of cases the
main vascular pedicle is derived directly from the profunda fem -
oris vessels. The main pedicle is most easily identi ed as it passes
between the adductor longus anteriorly and the adductor brevis
and magnus muscles posteriorly. The dominant vascular pedicle
enters the m uscle belly 8 to 12 cm inferior to the pubic tubercle
on its deep surface. The pedicle then sends branches superiorly,
inferiorly, and transversely throughout the muscle. A minor ped-
icle can be found proxim al to the m ain vascular pedicle in ap-
proximately 85% of cases as a branch of the obturator vessels, the
medial fem oral circum ex vessels, directly from the femoral ves-
sels, or from the ascending branch of the main pedicle. Ligation
of this proximal minor pedicle does not adversely a ect blood
supply to the ap.
Distal to the main pedicle, there are multiple minor pedicles
consisting of an artery and accompanying vein that supply the
middle and distal part of the gracilis m uscle. These distal pedi-
cles arise from the super cial fem oral artery and the m ost distal
minor pedicle can arise from the popliteal vessels. The cutaneous
territory of the entire gracilis ap forms a T shape composed of
two or three vascular territories with intercommunications be-
tween the major and minor pedicles in the fasciocutaneous por-
tion of the gracilis ap. Adhering to Taylor’s angiosom e concept,
only one adjacent perforator zone can be incorporated into a ap
based solely on the main pedicle to prevent distal skin necrosis.
Perforator Vessels
Most m usculocutaneous perforators are located in the proxi-
mal two-thirds w ith the highest concentration and largest of
these perforators within the proxim al third of the m uscle with
a tendency to travel in a transverse direction. The length of the
skin paddle when placed vertically should not exceed two-thirds
of the muscle length. One or two large musculocutaneous perfo-
rators exit the medial or lateral side of the muscle. Septocutane-
ous perforators may arise from the main gracilis vascular pedicle
between the adductor longus and the gracilis m uscle. More fre-
quently the signi cant septocutaneous perforator is from the rst
minor pedicle distal to the main pedicle, which is a direct branch
of the super cial femoral artery. These proximal musculocuta-
neous and septocutaneous perforators contribute to success of
the transverse orientation of the skin paddle. Anatomic studies
suggest that small-volume aps can be harvested based on the
septocutaneous perforator from the minor pedicle with no need
for muscle harvest.

●
Mean arterial diameter: 1.5 mm (range 0.5–2.0 mm)

●
Mean venous diameter: 2.0 mm (range 0.5–3.0 mm)

●
Length: 6 to 8 cm

●
Sensory innervation: cutaneous branch of the obturator
nerve supplies medial thigh skin

●
Motor innervation: anterior branch of obturator nerve

Patient Positioning
Supine position with all pressure points padded. The donor lower
extrem ity is abducted with gentle exion of the hip and knee
joints with a rolled towel beneath the knee to facilitate access to
the muscle (Fig. 19.1).

Surface Markings
1. Mark the pubic tuberosity and the medial tibial condyle
(Fig. 19.2).
2. Palpate and mark the adductor longus muscle, as the graci-
lis muscle is located just posteriorly. Note, the gracilis muscle
is unique as the only muscle in the adductor compartm ent
that passes across both the hip joint and the knee. Using this
characteristic, it can be identi ed by palpation just proxim al
to the knee during knee extension (palpable) because it then
becomes impalpable during knee exion while the hip is
abducted (Fig. 19.3).
3. The approximate course of the anterior border of the muscle is
traced by drawing a straight line just posterior to the tendon
of the adductor longus connecting the pubic tubercle to the
medial femoral condyle.
4. Mark the width of the muscle (5 to 8 cm in adults) (Fig. 19.4).

19 Gracilis Muscle and Myocutaneous Flaps
231
5. Apply a handheld Doppler to a point approximately 8 to 10 cm
from the pubic tubercle and carefully search for arterial signals.
6. Mark the strongest, most prominent signals with a large X.
7. The skin paddle can now be designed around the most prom -
inent signal, m arked X. A transverse upper gracilis (TUG) skin
paddle centered over the upper third of the muscle can mea-
sure up to 30 cm 3 10 cm (Fig. 19.5). The skin island is out-
lined as a crescent with one tip in the lateral anterior groin
and the other tip in the proximal posterior thigh. The prox-
imal limb of crescent is approxim ately 4 cm inferior to the
gluteal–groin crease. The pinch technique is used to ensure
adequate tension-free primary closure. A vertical or longitu-
dinal skin paddle is designed as an ellipse with the proximal
incision 2 to 3 cm below the pubic tubercle (Fig. 19.6). The
skin island must include the proximal muscle and may extend
to the middle third of the muscle with dimensions up to 8 cm
wide 3 15 cm long. Ultimately, regardless of the orientation
of the skin island, the width is determined by skin laxity, the
amount of subcutaneous tissue, and the soft tissue require-
ment at the recipient site.
Fig. 19.2 Anatomic diagram of gracilis muscle: 1, gracilis muscle; 2, sartorius
muscle; 3, adductor longus muscle; 4, rectus femoris muscle; 5, pectineus
muscle; 6, femoral artery; 7, deep femoral artery; 8, branch to gracilis muscle.1
Fig. 19.1 Patient positioning for gracilis  ap harvest. The donor lower ex-
tremity is abducted with gentle  exion of the hip and knee joints with a 
rolled towel beneath the knee to facilitate access.

Raising the Flap
Step 1: Preparing the Limb
It is recommended that surgical loupes are used during the dis-
section of this ap. No tourniquet or exsanguination is necessary.
Shave all hair prior to making any incisions.
Step 2: Incision (No Skin Paddle)
Along the axis of the muscle, make a proximal incision with the
scalpel down through the deep dermis (Fig. 19.7). Electrocautery
is then used to deepen the incision into the subcutaneous fat.
If the saphenous vein is encountered, care is taken to preserve
the vein during dissection. The gracilis muscle is identi ed and

232
II Reconstructive Flaps A-to-Z
Fig. 19.3 The gracilis muscle is identi ed by extension of the knee in thigh abduction. The 
gracilis is the only muscle of the adductor compartment to cross both the hip joint and 
the knee joint. This makes it palpable on knee extension but impalpable on knee  exion.
Fig. 19.4 The skin marking of the muscle.
the fascia is opened (Fig. 19.8). The fascia is then elevated o the
muscle anteriorly. Once the septal junction of the gracilis and ad-
ductor longus is identi ed, the space is entered. Gentle retrac-
tion is applied to separate the two muscles and the pedicle to
the gracilis muscle is identi ed in this plane (Fig. 19.9). During
the dissection, care is also taken to avoid injury to the anterior
cutaneous nerve of the thigh to prevent postoperative nerve in-
jury complications.
Identi cation of the gracilis here is aided by identifying
the only m uscle (gracilis) that becom es taut upon knee exten-
sion in hip abduction and it is also the only m uscle that can
be dissected circum ferentially in the adductor compartm ent.
Having identi ed it proxim ally, a distal incision (longitudinal)
is com m only added if the entire length of the gracilis is re-
quired. Distally, the tendon is found just posterior to the sar-
torius m uscle and anterior to the sem im em branosus. Careful
placem ent and traction on a vessel loop around the m uscle
proxim ally (distal to the neurovascular bundle) and distally
w ill facilitate identi cation of the gracilis prior to tendon tran-
section (Fig. 19.10).
Step 3: Retrograde Pedicle
Dissection
Use careful blunt dissection to fully expose the pedicle. Identify the
anterior branch of the obturator nerve as it enters the muscle belly
1 to 2 cm proximal to the vessels. The main pedicle is followed by
blunt dissection in the plane below the adductor longus and above
the adductor brevis and magnus back to its origin (Fig. 19.11).
Depending on length of pedicle needed, this dissection can
be carried out back to the profunda femoris. All branches to the
adductor longus are ligated and divided. If nerve coaptation is
planned for a functional muscle transfer, blunt dissection is used

19 Gracilis Muscle and Myocutaneous Flaps
233
incision along the medial thigh for distal dissection. Alternatively,
a counterincision may be created at the medial side of the tibial
head to facilitate distal dissection as mentioned above. The ten-
don of the gracilis muscle is identi ed and released. Care is taken
not to injure the saphenous nerve during dissection of the ten-
dinous portion. Do not release the sartorius or semitendinosus
tendons, which contribute to the pes anserinus.
Prior to tendon release, if the m uscle is to be used for
functional repair, it is as this point that the gracilis muscle is
stretched to its maximum in situ length and marking sutures are
placed at 5-cm intervals to preserve key muscle length–tension
relationships. Additionally, in the case of functional muscle
transfer, the entire width of the m uscle m ay not be needed and
the m uscle m ay be split longitudinally based on nerve fascicular
to free the nerve from its surrounding tissue and the m otor nerve
is dissected as far as possible, often to the bifurcation of the
obturator nerve.
Step 4: Free Muscle from
Anatomical Location
Continue to dissect distally along the anterior border of the mus-
cle. Ligate all m inor pedicles as the dissection progresses. Lift
the gracilis m uscle away from the adductor m usculature. The
muscle can then be divided w ith electrocautery at its distal lo-
cation unless the tendinous portion is needed. Note that at this
stage som e surgeons will continue the initial incision as a lazy S
Fig. 19.6 Longitudinal skin paddle design.
Fig. 19.5 Transverse skin paddle design.

234
II Reconstructive Flaps A-to-Z
territory. Once the tendon is released distally, turn attention back
to the posterior portion and release the gracilis muscle from its
posterior fascial attachments. Use electrocautery to divide the
muscle proximally (Fig. 19.12).
Step 5: Check Flap Vascularity
Now the ap is connected only via the neurovascular pedicle.
Check the circulation to the skin paddle (if included) and to the
distal end of the muscle. If healthy bleeding edges are not iden-
ti ed, debride nonviable tissue conservatively back to viable
tissue edges.
Step 6: Vessel Ligation
If a free ap is being utilized, place clips on the pedicle vessels
at the chosen level and divide sharply with scissors distal to the
clips. It is not necessary to place clips on the ap side; this avoids
a
Fig. 19.7 (a) Location of incision for muscle only  ap harvest: 1, gracilis muscle; 2, adductor longus muscle; 9, semi-
tendinosus muscle.1 (b) An incision is made proximally.
b

19 Gracilis Muscle and Myocutaneous Flaps
235
Fig. 19.8 The incision is directed straight down to the deep fascia.
Fig. 19.9 A blue vessel loop is passed around the distal gracilis to facilitate dissection.

236
II Reconstructive Flaps A-to-Z
Fig. 19.10 (a) Vascular pedicle approach: 1, gracilis muscle; 2, adductor longus muscle; 3, adductor brevis muscle; 
4, adductor magnus muscle; 5, branch from deep femoral artery and vein; 6, anterior branch of obturator nerve.1
(b) The main arteriovenous pedicle (from the medial femoral circum ex vessels) is visible passing deep to the anterior 
border of the muscle approximately 8 to 10 cm from its proximal insertion. The nerve to the gracilis enters in the same 
plane approximately 1 to 2 cm proximal to the main pedicle. In this case a secondary pedicle is appreciated and a micro-
vascular clamp has been placed to test the blood supply to the muscle from the dominant pedicle. The adductor longus 
is retracted anteriorly allowing dissection and exposure of the main pedicle.
a
b

19 Gracilis Muscle and Myocutaneous Flaps
237
Fig. 19.11 (a) Exposure of the distal gracilis: 1, gracilis muscle; 2, adductor longus muscle; 7, semimembranosus muscle;
8, sartorius muscle. (b) Completion of muscle  ap: 1, gracilis muscle; 2, adductor longus muscle; 3, adductor brevis muscle; 
4, adductor magnus muscle; 5, branch from deep femoral artery and vein; 6, anterior branch of obturator nerve.1
a
b
unnecessary trauma to the vessels. Clip and divide the anterior
branch of the obturator nerve. If a functional muscle transfer is
indicated, clip and divide the nerve at the desired proximal level
(Fig. 19.13). The ap is then m oved to the recipient site for vas-
cular anastomosis and inset. If a pedicle ap is being utilized, the
main pedicle is not divided but protected from kinking and twist-
ing as the ap is rotated or tunneled to the recipient site.
Step 7: Donor Site Closure
Once the ap has been rem oved, the donor site is irrigated and
explored for meticulous hem ostasis. The m uscular fascia does
not need to be closed. A suction drain is placed to prevent post-
operative seroma. The skin is then closed in layers with size
2-0 sutures in Scarpa’s fascia, 3-0 sutures in a deep dermal layer,

238
II Reconstructive Flaps A-to-Z

Skin Paddle Techniques
Transverse Skin Paddle
Use a scalpel to m ake all incisions along preoperative markings.
Elevate the edges of the ap in a suprafascial plane using electro-
cautery. Care is taken to preserve venous and lymphatic structures
and a 4-0 running subcuticular stitch for nal skin approxim ation
(Fig. 19.14). Absorbable sutures are used for each layer. If the skin
paddle area cannot be reapproxim ated with acceptable tension,
then a skin graft may be indicated; however, skin graft after a
gracilis myocutaneous ap is rare and would likely be due to an
error in ap design such as inappropriate estimation based upon
pinch test.
Fig. 19.12 The distal end of the  ap is divided and checked for active arterial bleeding at the distal end. The dominant 
pedicle is then traced back to its origin to maximize length.
Fig. 19.13 The  ap is isolated from the leg and is noticeably shorter ex vivo. When used for functional muscle transfer, 
marking of muscle length under tension before harvest (e.g., in 5-cm increments) permits appropriate tension at the 
recipient site, if required.

19 Gracilis Muscle and Myocutaneous Flaps
239
Fig. 19.14 The donor site is closed in layers over a closed suction drain.
seen during the dissection. Along the posterior incision care is
taken not to injure the posterior femoral cutaneous nerve. When
approaching anteriorly, the fascia at the posterior border of the
adductor longus muscle is incised. The adductor longus is then
retracted to expose the vascular pedicle to the gracilis muscle.
The dissection is then perform ed in a sim ilar fashion as outlined
above. Closure is also performed as outlined above with the ex-
ception of advancing the lower wound edge toward the m idline
to prevent dog ears, similarly to a medial thigh lift closure.
Longitudinal Skin Paddle
Use a scalpel to make the anterior incision that was previously
marked. Use electrocautery to dissect through the subcutaneous
fat at an oblique angle away from the ap to prevent undermining
of the skin paddle. Identify the gracilis muscle distally and con-
rm that the skin paddle is directly over the muscle. If necessary,
readjust skin paddle design to ensure proper placement. From
the anterior approach, the fascia of the adductor longus is ex-
posed and incised longitudinally. The fascia of the adductor lon-
gus is then elevated posteriorly, and with lateral retraction of the
adductor longus, the main vascular pedicle and motor nerve are
exposed. This m aneuver exposes the m ain vascular pedicle as it
travels between the adductor longus and brevis m uscles to enter
the deep surface of the gracilis m uscle. The septum is included in
the dissection to preserve the septocutaneous perforators con-
tributing to the blood supply of the overlying skin. Now turn at-
tention to the posterior margin of the skin paddle and perform
subcutaneous dissection in a similar fashion down to fascia to
expose the gracilis m uscle. Identify and protect the great saphe-
nous vein during dissection. The gracilis musculocutaneous ap
is then harvested as outlined above.

Important Anatomical
Structures
Identi ed and raised with ap:
1. The skin paddle should not exceed greater than two-thirds the
length of the gracilis muscle to prevent skin necrosis. Dimen-
sions of skin paddle are determined by skin laxity for direct
closure.
2. Identify and carefully dissect along the anterior branch of the
obturator nerve.
3. Identify and carefully dissect along the main pedicle back to
its origin.
Identi ed and preserved:
1. Do not damage the great saphenous vein.
2. Do not damage the saphenous nerve.
3. Do not damage the anterior cutaneous nerve of the thigh.
4. Do not damage the posterior cutaneous nerve of the thigh
during transverse skin paddle harvest.
5. Preserve the remaining muscles of the adductor compartment.

Clinical Perspectives
The gracilis m uscle is a long and thin muscle that serves
as a workhorse for reconstructive microsurgery. The close
relationship between the nerve and vessels allows the gracilis
ap to be easily raised on what amounts to a single main neu-
rovascular pedicle. The muscle can be used as a muscle-only
ap or its musculocutaneous and septocutaneous perforators
allow it to be used as a musculocutaneous ap. The gracilis

240
II Reconstructive Flaps A-to-Z
suturing the deep surface of the skin island to the gracilis muscle
borders can help avoid perforator traction damage during the ap
elevation. The deep fascia is always incised and the adductor lon-
gus is retracted anteriorly to expose the pedicle vessels. Before
pedicle ligation be sure to check the recipient vessels to ensure
vessel diameter compatibility to ensure that further pedicle dis-
section is not needed to achieve a greater diameter. While the
muscle is commonly divided using electrocautery, the use of a
bowel stapler has been reported in the literature as a method of
gracilis division during harvest as the staples can be useful for
hemostasis and provide anchors for suturing the muscle in place
during facial reanimation cases. If a functional muscle transfer
is planned, it is important to mark the gracilis under stretch at
de ned intervals to maintain the appropriate length–tension
relationship during inset.
muscle/myocutaneous ap has a vast applicability that includes
functional muscle transfer, wound coverage, and breast recon-
struction. The low donor site morbidity, acceptable donor site
scar, and reliable vascular pedicle m ake the gracilis muscle/
myocutaneous ap a favorite am ong many reconstructive sur-
geons as a pedicle or free ap (Figs. 19.15, 19.16, and 19.17).

Hints and Tips
Ensure meticulous hem ostasis throughout the dissection to opti-
mize visibility and limit blood loss. Always center the skin island
over the gracilis muscle. Limit the skin island to the proximal two-
thirds of the m uscle belly to avoid distal necrosis. Temporarily
Fig. 19.15 (a) Right breast cancer with mark-
ings for mastectomy; the third costal cartilage is
marked for removal. (b) Right thigh transverse 
gracilis myocutaneous  ap is marked. (c) Cosmesis
of donor site at 2 weeks. (d) Cosmesis at recipient
site (breast reconstruction) at 2 weeks. 
a
c
d
b

19 Gracilis Muscle and Myocutaneous Flaps
241
Fig. 19.16 (a) Recurrent vaginal cancer with preoperative left thigh longitudinal gracilis myocutaneous  ap markings. 
(b) Immediate postoperative result after pedicled gracilis myocutaneous  ap tunneling and inset into vaginal defect. 
(c) Cosmesis of donor and recipient site at 2 months.
a
b
c

242
II Reconstructive Flaps A-to-Z
Fig. 19.17 (a) Dissection of right gracilis muscle for facial reanimation showing the main pedicle passing behind the adductor longus muscle to enter 
the muscle 1 to 2 cm distal to the entry of the nerve to gracilis. (b) View from opposite side demonstrating use of a nerve stimulator to identify the 
best half of the gracilis to take for the transfer. (c) The hemigracilis is inserted in the subcutaneous facelift plane for facial reanimation and sutured at 
physiological length to the modiolus, nasolabial fold, and ipsilateral alar root. (d) Muscle now in place with vessels anastomosed to the facial vessels and 
the nerve coapted to the crossed facial nerve graft within the upper lip.
a
b
c
d
Suggested Further Reading
Arnez ZM, Pogorelec D, Planinsek F, Ahcan U. Breast reconstruction by the
free transverse gracilis (TUG) ap. Br J Plast Surg 2004;57(1):20–26
Giordano PA, Abbes M, Pequignot JP. Gracilis blood supply: anatom ical
and clinical re-evaluation. Br J Plast Surg 1990;43(3):266–272
Kind GM, Foster RD. The longitudinal gracilis myocutaneous ap:
broadening options in breast reconstruction. Ann Plast Surg
2008;61(5):513–520
Shridharani SM, Stapleton SM, Redett RJ, Magarakis M, Rosson GD. Use of
gastrointestinal anastomosis stapler for harvest of gracilis m uscle
and securing it in the face for facial reanim ation: a novel technique.
Eplasty 2010;10:e29
Taylor GI, Cichowitz A, Ang SG, Seneviratne S, Ashton M. Comparative
anatomical study of the gracilis and coracobrachialis muscles:
implications for facial reanim ation. Plast Reconstr Surg 2003;112(1):
20–30
Whitaker IS, Karavias M, Shayan R, le Roux CM, Rozen WM, Corlett RJ, et
al. The gracilis myocutaneous free ap: a quantitative analysis of
the fasciocutaneous blood supply and implications for autologous
breast reconstruction. PloS One 2012;7(5):e36367
Yousif NJ, Matloub HS, Kolachalam R, Grunert BK, Sanger JR. The trans-
verse gracilis m usculocutaneous ap. Ann Plast Surg 1992;29(6):
482–490
Figure Credits
1. Strauch B, Yu HL. Atlas of Microvascular Surgery: Anatomy and Oper-
ative Approaches. 2nd ed. New York, NY: Thieme; 2006

243
branch runs m ore laterally and gives o m usculocutaneous
perforators, w hich pierce the sartorius m uscle and fascia before
supplying the skin.
The super cial vein travels parallel to the axis of the super -
cial circum ex iliac artery system. The venae comitantes are of-
ten small and inadequate for anastomosis and they often drain
into the super cial vein. Hence, the super cial vein is used for
anastomosis in the majority of cases. In cases where there is a
small or absent super cial vein, the venae comitantes are usually
of a larger caliber.

●
Mean arterial caliber: 0.7 mm (0.4–1.2 mm)

●
Length: , 5.0 cm (2.5–7.0 cm)

Patient Positioning
Supine.

Classi cation

●
Mathes-Nahai (fasciocutaneous): type A

Vascular Pedicle
The skin overlying the right groin region is supplied by the su-
per cial and deep branches of the super cial circum ex iliac
artery (Fig. 20.1). A traditional groin ap includes the skin,
underlying fat, and deep fascia and is raised based on the su-
per cial circum ex iliac artery system . In the pursuit for aps
w ith less donor site m orbidity, the super cial circum ex iliac
perforator (SCIP) ap was evolved. The SCIP ap includes only
the skin and the subcutaneous tissues above the deep fascia,
and it can be based on either the super cial or deep branch
of the super cial circum ex iliac artery. The super cial branch
runs m edially and has a direct septocutaneous course. The deep
Groin and Super cial Circum ex Iliac
Perforator Flaps
Terence Goh, Kok Chai Tan, and Joon Pio Hong
20
Fig. 20.1 Elevation of a super cial circum ex iliac perforator  ap in the super cial plane. The  ap is elevated at the 
level of the super cial fascia, preserving the deep fat, along with the lymphatics and the lymph nodes. The  ap can be 
reliably based on the super cial branch (^) 92% of the time, or the deep branch (*) if the super cial branch is too small. 
The indirect linking vessels, which traverse the super cial fat, provide the perfusion in between the perforators when 
the direct linking vessels are ligated. The super cial vein traverses the plane between the super cial and deep fat and is 
included in the  ap for venous drainage.

244
II Reconstructive Flaps A-to-Z
5. Perform a pinch test to con rm laxity for primary closure of
the donor site. The maximum width of the ap that can be
raised while permitting primary closure is approximately
8 cm, but up to 10 cm in a lax individual.
6. The length of the ap can be extended laterally beyond the
anterior superior iliac spine or medially toward the groin.
7. The groin ap is often raised as a pedicled ap with a point of
rotation over the femoral artery below the inguinal ligament.
The ap is able to reach the umbilicus and perineum; it is also
used commonly for coverage of upper limb defects.

Raising the Flap
Step 1: Assess and Prepare
Recipient Site
Preoperatively, ultrasound Doppler is used to mark the poten-
tial recipient perforators or pedicle around the soft tissue defect.
Before comm encem ent of the reconstruction, perform complete

Surface Markings
(The markings for the groin ap and the SCIP ap are similar.)
1. Mark the inguinal ligament from the pubic tubercle to the
anterior superior iliac spine. The perforators originating from
the super cial inferior epigastric artery lie above it, and below
it lie the perforators originating from the super cial circum-
ex iliac artery (Fig. 20.2).
2. Draw a line from the inguinal crease to the anterior superior
iliac spine; this marks the axis of the SCIP ap.
3. Apply the handheld Doppler probe 1 to 2 cm below the axis
demarcated in Step 2. Carefully search for perforators origi-
nating from the super cial circum ex iliac artery.
4. Outline the ap design to include as many perforators as feasible,
and center the ap toward the medial aspect of the groin; match
the dimensions of the ap to the size of the defect. By designing
the ap along the axis from the inguinal crease to the anterior su-
perior iliac spine, the maximum number of perforators (average,
2.3) will be included in the ap along with the super cial vein.
Fig. 20.2 (a,b) Surface markings and  ap design. An imaginary line (red line) drawn from 
the pubic tubercle (PT) to the anterior superior iliac spine (ASIS) denotes the inguinal 
ligament. Above it lie the perforators originating from the super cial inferior epigastric 
artery, and below it lie the perforators originating from the super cial circum ex iliac 
artery. The axis (blue line) of the super cial circum ex iliac perforator  ap runs in the 
direction from the groin crease toward the anterior superior iliac spine. By designing the 
skin paddle along this axis, the maximum number of perforators (average, 2.3) will be 
included in the  ap along with the super cial vein.
a
b

20 Groin and Super cial Circum ex Iliac Perforator Flaps
245
Step 2: Begin Flap Elevation
Inferolaterally in the Deep Fascial
Plane (Groin Flap)
The groin ap is elevated at a deeper plane compared to the SCIP
ap. It is raised at the level of the deep fascia to include both the
branches of the super cial circum ex iliac artery (Fig. 20.5). The
super cial circum ex iliac artery travels approximately 2 to 3 cm
below and parallel to the inguinal ligament taking origin from the
femoral artery while the super cial vein travels super cial to the
artery and drains into the saphenous vein (Fig. 20.6).
The groin ap is often elevated as a pedicled ap w ith the
base left intact. Similar to the SCIP ap, a skin incision is made and
the ap is elevated in a lateral to m edial direction. When the lat-
eral edge of the sartorius is visualized, the fascia of the sartorius
is included in the ap. The medial edge of the sartorius denotes
the proxim al limit of the groin ap as the pedicle arises m edial to
this point. The medial portion of the ap is often tubularized to
protect the pedicle. In cases where a free ap is required, an SCIP
ap is raised instead.
The pedicle of the groin ap can be divided after 14 to
21 days. This is often done progressively over a few days.
and thorough debridement of the recipient site, extending to the
bone when necessary. Bony xation is performed before soft tis-
sue reconstruction. Dissect and isolate the recipient vessels un-
der the m icroscope to con rm patency and to estim ate the length
of the pedicle required.
Step 2: Begin Flap Elevation
Inferolaterally in the Suprascarpal
Plane (SCIP Flap)
Commence elevation of the ap along the inferior and lateral
borders under 43 loupe magni cation (Fig. 20.3). The dissec-
tion plane, which is identi ed most clearly inferolaterally, lies
above the Scarpa’s fascia, in between the super cial and deep fat
(Fig. 20.4). The Scarpa’s fascia is visible as a distinct white fas-
cial layer separating the super cial smaller fat lobules from the
deeper, larger fat lobules; this is most evident in a patient with a
higher body mass index.
It is recommended that diathermy needle dissection is used
to ensure a bloodless surgical eld, which is essential so that
staining of the tissue does not interfere with subsequent identi -
cation of the perforators.
Fig. 20.3 Elevation of the  ap from the inferolateral border.
Fig. 20.5 Deep branch (*) of the super cial circum ex iliac artery identi ed.
Fig. 20.4 Identi cation of the suprascarpal plane.
Fig. 20.6 Super cial branch (^) of the super cial circum ex iliac artery 
identi ed.

246
II Reconstructive Flaps A-to-Z
Step 6: Donor Site Closure
The super cial fascia layer is plicated together with absorbable
2-0 sutures before the dermis and skin sutures are placed. It is
important to obliterate the dead space and prevent seroma for-
mation. Closure is perform ed over one Jackson-Pratt drain. If the
ap width exceeds 8 cm or the closure is tight, the groin is exed
to 45 degrees for 5 days to reduce tension on the wound.

Important Anatomical
Structures
Identi ed and raised with the ap:
1. Super cial branch of the super cial circum ex iliac artery
(deep branch if the super cial branch is not suitable)
2. Super cial vein
3. The groin ap includes the deep fascia, deep fat, and the
super cial lymph nodes
Identi ed and preserved:
1. Scarpa’s fascia and deep fat (which contains the lymphatics,
lymph nodes, and cutaneous nerves) are routinely preserved
in the SCIP ap.

Clinical Perspectives
The super cial circum ex iliac perforator ap is a thin skin ap
that can be used for accurate resurfacing of moderate-size defects
in all regions of the body (Fig. 20.9). It o ers several advantages:
the donor site is inconspicuous and easily concealed, and the
thin ap is suitable in regions that do not tolerate bulkiness, such
as the dorsum of the foot (Figs. 20.9, 20.10, and 20.11), around
the toes and web spaces, in cutaneous defects of the upper limb
(Fig. 20.12), and head and neck defects, such as resurfacing the
external auditory meatus or reconstruction of the tongue.
Step 3: Identi cation of Deep
and Super cial Branches of the
Super cial Circum ex Iliac Artery
and Super cial Vein
Continue elevating the ap from lateral to medial, taking care
to identify the deep and super cial branches of the super cial
circum ex iliac artery. The deep branch is more lateral and is
identi ed rst (Fig. 20.7), followed by the super cial (and m ore
medial) branch.
The super cial vein is identi ed and preserved. It courses
near the super cial branch of the super cial circum ex iliac
artery.
Step 4: Assess Suitability of
Deep and Super cial Branches
Next, skeletonize the perforators toward the deep fascia. Assess
the adequacy of blood supply to the ap provided by the su-
per cial branch by applying m icrovascular clamps to the deep
branch. If the perfusion of the ap continues to be su cient,
the deep branch is ligated and the ap is raised on the super-
cial branch (Fig. 20.8). The septocutaneous super cial branch
is preferable as it avoids the need for tedious intram uscular
dissection.
If the super cial branch is small and deemed to be inade-
quate, then the deep branch is used instead.
Step 5: Retrograde Pedicle
Dissection
Perform the pedicle dissection retrogradely toward the super-
cial circum ex iliac artery (Fig. 20.8). The deep fascia can be
incised to obtain a longer pedicle (up to 7 cm) and larger vessel
diameter if necessary.
Fig. 20.7 Selection between the super cial (^) and deep branches (*) of 
the super cial circum ex iliac artery.
Fig. 20.8 Tracing the perforator beyond the femoral sheath.

20 Groin and Super cial Circum ex Iliac Perforator Flaps
247
Furthermore, elevating the ap above the Scarpa’s fascia
o ers an expeditious and reliable m eans of obtaining a safe and
vascularly robust ap, and m arkedly reduces the need for sec-
ondary debulking procedures. Preservation of deep structures
and lymph nodes also prevents the complications of wound
dehiscence and lymphorrhea.
In current literature, this ap is conventionally applied in
defects where the recipient vessels are super cially located, such
as the foot, genital area, or upper lim b; the pedicle of the ap is
5 cm and thus would normally require vascular grafts in order to
reconstruct defects in the m iddle or upper third of the leg, or in
the head and neck region.
However, the ap can potentially be applied to more an-
atomical regions with the following modi cations: dissecting
the vessel beyond the deep fascia to obtain an extra 1 to 2 cm
of pedicle length, and using the supermicrosurgery concept of
anastomosing the perforator-to-perforator or distal branches of
the artery in the periphery of the defect to econom ize the vessel
length required and reduce vessel lumen discrepancy.
Use of this ap also m inim izes the sacri ce of a m ajor
vessel, w hich is useful in salvage of a lim b w ith only one
rem aining m ajor vessel, and in diabetic patients w here
the perforators are often the only vessels spared from the
m acrovascular disease.
Fig. 20.9 Reconstruction for distal leg wound with a super cial circum ex 
iliac perforator  ap. This patient fell from height and sustained fractures of 
the left tibia and  bula, with a resultant skin defect and bone gap. (a) The 
exposed bone and tendon were  rst covered with a super cial circum-
ex iliac perforator  ap. (b) Two months later, the  ap was re-elevated for 
removal of antibiotic beads and secondary bone grafting. (c) Postoper-
ative appearance. This case demonstrates the thinness of the super cial 
circum ex iliac perforator  ap, and the ease with which it can be elevated.
a
b
c

248
II Reconstructive Flaps A-to-Z
Fig. 20.10 Reconstruction for traumatic foot injury with a super cial circum ex iliac perforator  ap. A 19-year-old woman sustained a right foot 
degloving injury with multiple fractures of the phalanges after her foot was rolled over by a bus. (a) Degloving injury of right foot. (b) Preoperative 
surface marking at the donor site. (c) Post-reconstruction with a super cial circum ex iliac perforator  ap. (d) Well-healed scar at the donor site.
a
b
d
c
Fig. 20.11 Reconstruction for diabetic foot infection with a super cial circum ex iliac perforator  ap. A patient with a diabetic foot infection underwent 
a forefoot amputation exposing the metatarsals. In order to preserve the length of the foot, a super cial circum ex iliac perforator  ap was used to 
cover the defect. (a) Forefoot amputation. (b) Raising the super cial circum ex iliac perforator  ap. (continued)
a
b

20 Groin and Super cial Circum ex Iliac Perforator Flaps
249
Fig. 20.12 Reconstruction of a left forearm defect with an ipsilateral pedicled groin  ap. A patient who sustained a volar wrist wound underwent 
resurfacing of the defect with a pedicled groin  ap. (a) Skin markings of the  ap. (b) The medial part of the  ap is tubularized to protect the pedi-
cle while the distal part of the groin is closed primarily. (c) The  ap is inset over the defect and the arm is kept close to the body until  ap division. 
(d) The patient at 1 month after  ap division demonstrating good range of motion of the left wrist.
a
c
b
d
Fig. 20.11 (continued) (c) Postoperative appearance of the foot.
c

250
II Reconstructive Flaps A-to-Z

Hints and Tips
Having an assistant stretch the skin during elevation of the ap
can enhance identi cation of the super cial fascial plane. When
dissection is performed accurately in the suprascarpal plane, the
whitish Scarpa’s fascia is left behind, and the fat globules elevated
in the ap are smaller in size and m ore distinct as compared to
the fat left behind.
Take particular care to dissect meticulously in the region of
the perforator markings, the “hot zone,” to search for the per-
forators. Dissection in the lateral and inferior parts of the ap
away from the perforators and the remainder medial and supe-
rior parts of the ap (the “cold zones”) can be perform ed m ore
quickly as there are no critical structures, thereby shortening ap
harvest time.
Once identi ed, the perforators should be handled with care
to minimize the complication of postoperative ap loss. This in-
cludes constant irrigation of the perforators to prevent dehydra-
tion, m eticulous handling under microscopic magni cation, as
well as adequate postoperative hydration.
Suggested Further Reading
Chuang DC, Jeng SF, Chen HT, Chen HC, Wei FC. Experience of 73 free groin
aps. Br J Plast Surg 1992;45:81–85
Daniel RK, Taylor GI. Distant transfer of an island ap by microvascular
anastomoses: A clinical technique. Plast Reconstr Surg 1973;52:
111–117
Demir A, Moham ed A, Cetingül HE. Online agglomerative hierarchical
clustering of neural ber tracts. Conf Proc IEEE Eng Med Biol Soc
2013;2013:85–88
Gharb BB, Salgado CJ, Moran SL, et al. Free antero-lateral thigh ap in
pediatric patients. Ann Plast Surg 2011;66:143–147
Goh TL, Park SW, Cho JY, Choi JW, Hong JP. The search for the ideal thin
skin ap: Super cial circum ex iliac perforator ap - A review of
210 cases. Plast Reconstr Surg 2015;135:592–601
Gottlieb LJ, Krieger LM. From the reconstructive ladder to the reconstruc-
tive elevator. Plast Reconstr Surg 1994;93:1503–1504
Hallock GG. A paradigm shift in ap selection protocols for zones of
the lower extremity using perforator aps. J Reconstr Microsurg
2013;29:233–240
Hollenbeck ST, Woo S, Komatsu I, Erdm ann D, Zenn MR, Levin LS. Longi-
tudinal outcom es and application of the subunit principle to 165
foot and ankle free tissue transfers. Plast Reconstr Surg 2010;125:
924–934
Hong JP, Choi DH, Suh H, et al. A new plane of elevation: The super -
cial fascial plane for perforator ap elevation. J Reconstr Microsurg
2014;30:491–496
Hong JP, Chung IW. The super cial fascia as a new plane of elevation for
anterolateral thigh aps. Ann Plast Surg 2013;70:192–195
Hong JP, Koshim a I. Using perforators as recipient vessels (superm icro-
surgery) for free ap reconstruction of the knee region. Ann Plast
Surg 2010;64:291–293
Hong JP, Sun SH, Ben-Nakhi M. Modi ed super cial circum ex iliac
perforator ap and supermicro- surgery technique for lower ex-
tremity reconstruction: A new approach for moderate-sized
defects. Ann Plast Surg 2013;71:380–383
Kim ura N, Satoh K. Consideration of a thin ap as an entity and clinical
applications of the thin anterolateral thigh ap. Plast Reconstr Surg
1996;97:985–992
Koshim a I, Nanba Y, Nagai A, Nakatsuka M, Sato T, Kuroda S. Penile recon-
struction with bilateral super cial circum ex iliac artery perforator
(SCIP) aps. J Reconstr Microsurg 2006;22:137–142
Koshim a I, Nanba Y, Tsutsui T, et al. Super cial circum ex iliac perfo-
rator ap for reconstruction of lim b defects. Plast Reconstr Surg
2004;113:233–240
McGregor IA, Jackson IT. The groin ap. Br J Plast Surg 1972;25:3–16
Ooi A, Wong CH, Ong YS. Combined use of liposuction and arthroscopic
shaver in lower-lim b fasciocutaneous ap contouring. J Plast
Reconstr Aesthet Surg 2013;66:538–542
Saint-Cyr M, Wong C, Schaverien M, Mojallal A, Rohrich RJ. The perfora-
some theory: Vascular anatomy and clinical implications. Plast
Reconstr Surg 2009;124:1529–1544
Taylor GI, Corlett RJ, Dhar SC, Ashton MW. The anatomical (angiosome) and
clinical territories of cutaneous perforating arteries: Developm ent
of the concept and designing safe aps. Plast Reconstr Surg 2011;
127:1447–1459
Wallace CG, Kao HK, Jeng SF, Wei FC. Free-style aps: A further step
forward for perforator ap surgery. Plast Reconstr Surg 2009;
124(Suppl):e419–e426
Wang HT, Fletcher JW, Erdmann D, Levin LS. Use of the anterolateral
thigh free ap for upper-extremity reconstruction. J Hand Surg Am
2005;30:859–864

251

Classi cation

●
Mathes and Nahai type V muscle ap

Vascular Pedicle
The inferior gluteal region has a vast supply of m usculocuta-
neous perforators that originate from the inferior gluteal ar-
tery and pierce the overlying gluteus m axim us to supply the
skin of the buttock (Fig. 21.1). These have been variably used
as either a pedicled flap for coverage of regional defects or as a
free flap for breast reconstruction. The inferior gluteal artery
originates w ithin the pelvis as the term inal branch of the in-
ternal iliac and enters the gluteal region through the greater
sciatic notch.

●
Mean arterial caliber: 2–3 mm

●
Mean venous caliber: 2.5–6 mm

●
Length: 4–5 cm but is increased when utilized as a perfo-
rator ap

●
Motor innervation: branches of the inferior gluteal nerve
(S1 and S2)

Patient Positioning
For the inferior gluteal artery myocutaneous ap (IGAM), prone.
(The lateral position is possible but not ideal.)

Surface Markings
1. Mark the coccyx.
2. Mark the greater trochanter of the femur.
3. Draw a line at 45 degrees. This denotes the line of the skin paddle.
4. Dot a line at 30 degrees to the vertical. This marks the inferior
edge of the gluteus maximus (Fig. 21.2).
5. Mark the pivot point of the ap approximately 5 cm lateral to
coccyx
6. Transcribe the width of the skin paddle required along the
45-degree line (Fig. 21.3a).
7. The length of the skin paddle is marked from the pivot point
and planned in reverse (Fig. 21.3b).
8. An oblique extension is added to allow access to the fascia lata
of the thigh.
9. At this point, a handheld Doppler may be used to locate skin
perforators, although this is not routinely required.
21
Inferior Gluteal Artery Musculocutaneous
Flaps
Dam ien Grinsell
Fig. 21.1 CT angiogram showing multiple musculocutaneous perfora-
tors in the gluteal region giving an abundant blood supply to the over-
lying skin.
Fig. 21.2 CT angiogram showing vertical orientation of gluteus maximus
muscle bers usually at an average of 30 degrees to the vertical.

252
II Reconstructive Flaps A-to-Z

Raising the Flap
Step 1: Inferior Incision
Palpate medial edge of gluteus m aximus through the perineal de-
fect and then make an inferior incision and dissect down to glute-
us m aximus. Dissect inferiorly in a subfascial plane and delineate
the inferior edge of gluteus maximus, preserving branches of the
posterior cutaneous nerve of the thigh (Fig. 21.4).
Step 2: Dissection of Inferior Edge
of Gluteus Maximus
Dissect around the inferior edge of gluteus maximus to gain the
deep surface of that muscle. Identify the fusion plane of gluteus
maxim us laterally into the fascia lata and ham strings. Dissect an
area the size of the perineal defect (usually 8 3 6 cm) super cially
to the fascia lata lateral to this fusion plane (Fig. 21.5).
Step 3: Superior Incision
Make superior incision and dissect down to gluteus m axim us
to gain the subfascial plane. Preserve any large skin perforators
encountered (Fig. 21.6). At this stage, the distal end (lateral) of
the skin paddle can be released from the underlying gluteus
maxim us by up to 40% to allow m ore preservation of the gluteus
maxim us m uscle. Split the gluteus m axim us along the line of its
bers planning to take the inferior one third to one fourth of the
muscle as a myocutaneous ap.
a

b
Fig. 21.3 (a) Mark the coccyx, greater trochanter, and inferior border of gluteus maximus at 30 degrees to the vertical. (b) The skin paddle is designed
o set to the line of the inferior border of the gluteus maximus at an angle of 45 degrees.
Fig. 21.4 Inferior incision made and subfascial dissection of gluteus
maximus preserving posterior cutaneous nerve of thigh.

21 Inferior Gluteal Artery Musculocutaneous Flaps
253
Fig. 21.5 Dissection on super cial surface of fascia lata lateral to fusion plane.
Fig. 21.6 Musculocutaneous perforator entering skin paddle at subfascial level.

254
II Reconstructive Flaps A-to-Z
nerve w ill accompany the perforators allow ing for innervated
ap transfer.
Step 7: Dissection of Main Inferior
Gluteal Artery (If Required)
Depending on the reach of the ap, at this stage, if needed, the in-
ferior gluteal artery can be dissected more medially to gain extra
length. This is usually not necessary.
Step 8: Release Inferior Skin Flap
for Donor Closure
Release the inferior skin ap to allow for easier transposition and
donor site closure.
Step 9: Inset Fascia into Perineal
Floor Defect
Transpose the myocutaneous island into the midline defect and
secure the fascia lata with large nonabsorbable sutures circum -
ferentially to the remnants of the perineal oor (Fig. 21.10). The
muscle will then ll any dead space. Place drains into donor site
and intrapelvic to reduce seroma formation.
Step 10: Close Donor Site
Transpose the lower skin ap and close in layers.
Step 4: Dissection of Fascia Lata
Design and incise the margins of the fascia lata extension centred
on the gluteus maximus muscle strip (Fig. 21.7). This is inferior to
the skin paddle and should measure approximately 8 3 6 cm. Raise
from lateral to medial until the fusion plane with gluteus maxi-
mus is determined. Divide the fusion plane leaving the fascia lata
in continuity with the lateral edge of gluteus maximus. This will
result in a trilaminar ap with fascia, muscle, and skin (Fig. 21.8).
Step 5: Raise the Flap from Lateral
to Medial
Continue dissection from lateral to medial on the deep surface of
the gluteus m axim us preserving the posterior cutaneous nerve
of the thigh. Multiple muscular perforators will be seen entering
the deep surface of the m uscle. The sciatic nerve will be encoun-
tered in the midline of the thigh but is on a deeper level and is
protected by deep fascia.
Step 6: Divide the Descending
Branch (If Required)
At this stage the m ain inferior gluteal artery w ill be encoun-
tered w ith its descending branch accompanying the posterior
cutaneous nerve of the thigh. This m ay need to be divided in
order to transpose the ap on a case-by-case basis. Preserva-
tion of the posterior nerve of the thigh is still possible w ith
this m aneuver (Fig. 21.9). Branches of the inferior gluteal
Fig. 21.7 Vascularized fascia lata extension raised from lateral to medial.

21 Inferior Gluteal Artery Musculocutaneous Flaps
255
Fig. 21.8 Trilaminar ap with skin, muscle, and vascularized fascia lata.
Fig. 21.9 Main inferior gluteal artery giving rise to the descending branch, which has been ligated. The posterior
cutaneous nerve of the thigh has been preserved. The sciatic nerve can be seen deep to the deep fascia and has
been preserved.

256
II Reconstructive Flaps A-to-Z
Fig. 21.10 (a) Muscle transposition with fascia lata inserted into pelvic defect. (b) Muscle trans-
position and inset of fascia lata into perineal hernia defect.
a
b

21 Inferior Gluteal Artery Musculocutaneous Flaps
257
Step 11: Inset the Skin Flap
Inset the skin ap in layers (Fig. 21.11).

Important Anatomical
Structures
Identi ed and raised with the ap:

●
Vascularized skin paddle and fascia lata based on the infe-
rior one-third to one-fourth of the gluteus m axim us. The
inferior gluteal artery and its m usculocutaneous branches,
along with branches of the inferior gluteal nerve, are
included.
Identi ed and preserved:

●
Posterior cutaneous nerve of the thigh

●
Sciatic nerve

Clinical Perspectives
The main focus of this ap is to reconstruct radical abdom inoper-
ineal resections commonly after chem oradiation. The vascular-
ized fascia lata provides structural integrity to the perineal oor
in the presence of irradiated tissue. The ap can be extended to
include much larger defects including vaginal reconstructions or
sacrectomies due to aggressive tumors or sarcomas. The ap can
be used without the fascial extension for any other defect in the
gluteal and sacral region, such as pressure sores or necrotizing
fasciitis (Figs. 21.12 and 21.13).

Hints and Tips
Make the design of the skin paddle longer than needed as the vas-
cularity of the skin is rich and the distal end can be discarded if
not needed or de-epithelialized to ll dead space. The pivot point
of the islanded transposition ap is 5 cm lateral to the coccyx
along the upper border of skin paddle.
The inferior edge of the gluteus m axim us is m ore vertical
than it seems, that is, 30 degrees to the vertical. Donor site clo-
sure is easier if the skin island is slightly o set at 45 degrees.
The distal 40% of the skin island can be released from the muscle
with preservation of good vascularity. This allows for less gluteus
maximus muscle to be taken with the ap.
Subfascial dissection of the inferior gluteus maxim us will
preserve the posterior cutaneous nerve of the thigh. The ischial
bursa may be encountered over the ischial tuberosity medially,
but it is of no consequence.
Ideally split the superior edge of the muscle along the line of
its bers and choose a line without any skin perforators as this
will avoid a tedious perforator dissection. Design the vascularized
fascia lata on the strip of gluteus maximus, which w ill be inferior
to the skin paddle. This will also avoid the trochanteric bursa.
Take care when dividing the fusion plane of gluteus maximus and
Fig. 21.11 Skin ap inset and donor site closure with inferior transposi-
tion ap.
a

b
Fig. 21.12 (a) Radical APR defect showing prostate anteriorly and large perineal defect. Sutures have been preplaced into perineal oor remnants for
later inset of fascia lata. (b) Well-healed ap with no hernia at 12 months and normal sensation.

258
II Reconstructive Flaps A-to-Z
Fig. 21.13 (a) Extended indication: large sarcoma defect
including rectum and sacrum and posterior vaginal wall. (b)
Intraoperative view with the IGAM ap raised and the vascular-
ized fascia lata being inset into the pelvic oor. (c) Final result.
a
c
b
Grinsell D, Morrison E, Tansley, PT. The inferior gluteal artery myocu-
taneous ap (IGAM) with vascularised fascia lata to reconstruct
extended abdom inoperineal defects. Plast Reconstr Surg 2013;
132(5):836e–840e
Le-Quang C. Secondary microsurgical reconstruction of the breast and
free inferior gluteal ap. Ann Chir Plast Esthet 1992;37:723–741
Windhofer C, Brenner E, Moriggl B, Papp C. Relationship between the
descending branch of the inferior gluteal artery and the posterior
femoral cutaneous nerve applicable to ap surgery. Surg Radiol
Anat 2002;24(5):253–257
Zenn MR, Millard JA. Free inferior gluteal ap harvest with sparing
of the posterior femoral cutaneous nerve. J Reconstr Microsurg
2006;22(7):509–512
the fascia lata, and it is important that the fascia is not detached
from the gluteus maximus at this stage.
If the descending branch of the inferior gluteal artery needs
dividing, it is important to dissect the posterior cutaneous nerve
of the thigh free and preserve it.
Suggested Further Reading
Boccola MA, Rozen WM, Ek EW, Teh BM, Croxford M, Grinsell D. Inferior
gluteal artery myocutaneous island transposition ap reconstruc-
tion of irradiated perineal defects. J Plast Reconstr Aesthet Surg
2010;63(7):1169–1175

259
The pedicle length is usually between 15 and 20 cm consid-
ering the course through the mesentery.
The caliber of the artery ranges between 1.5 and 2.5 m m ,
w ith the vein ranging between 2.0 and 4.0 mm.
The vein can be friable, and care m ust be taken in harvesting
the pedicle though the mesentery.
The upper portion of the jejunum is usually supplied by a
single arcade giving o several long vasa recta; the lower portion
contains two or three arcades which give o shorter vasa recta.
Although a vascularized segment can be harvested anywhere
from the ligament of Treitz to as far as 150 cm beyond, the longest
pedicle is achieved 40 cm distal to the ligament. The rst is not
usually chosen because its origin is high and deep, it is of insu -
cient length, and it supplies a relatively short segment of intestine.
This allows the second, third, or fourth intestinal branches
to be selected as the vascular pedicle; the m ost com m only se-
lected branch is the second one, with the other branches used for
secondary jejunal aps should the rst ap not survive.

Classi cation
The jejunal free ap is a vascularized intestinal conduit that can
be classi ed equivalent to a Mathes and Nahai type I ap, with
each jejunal segm ent nourished by a m ajor pedicle from the
superior mesenteric axis.

Vascular Pedicle
The jejunum is supplied by the superior mesenteric artery (SMA)
and its branches along its mesenteric border. The SMA arises from
the anterior aspect of the abdominal aorta 1 cm inferior to the celiac
trunk and travels down the mesentery toward the right iliac fossa.
The SMA has the middle colic, right colic, and ileocolic branches orig-
inating from its right side. The jejunal and ileal branches originate
from the left side of the SMA. Generally, the jejunal branches are lon-
ger than the ileal branches and less frequent in number (Fig. 22.1).
Jejunal Flap Reconstruction for
Circumferential Pharyngolaryngectomy
Defects
Pouria Moradi, Charles A. T. Durrant, and Sim on H. Wood
22
Fig. 22.1 Anatomy of the free jejunum. 1, Stomach; 2, small intestine (jejunum and il-
eum); 3, colon; 4, duodenum; 5, aorta; 6, superior mesenteric artery; 7, jejunal branch;
8, arterial arcade; 9, vasa recta.1

260
II Reconstructive Flaps A-to-Z
Step 4
The peritoneum overlying the mesenteric vessels is incised and the
pedicle dissected out. This dissection has to be performed meticu-
lously to ensure all the small friable vessels, especially the mesen-
teric veins, are ligated to avoid mesenteric hematoma (Fig. 22.5).
Step 5
The segment of jejunum isolated is de ned and clamped with non-
crushing bowel clamps. The jejunum is clamped proximally rst
and then manually emptied (Fig. 22.6). The bowel is divided and
allowed to perfuse on the dissected pedicle (Figs. 22.7 and 22.8).
Step 6
Before the pedicle is divided, the recipient vessels, usually the
superior thyroid artery and internal jugular vein, need to be pre-
pared and ready for microanastomosis. The pedicle is then ligated
and quickly transferred to the neck region for anastomosis.
Step 7
The ap is rst anastom osed to the cervical esophagus in an iso-
peristaltic manner, w ith sutures or an intestinal stapler, depend-
ing on the surgeon’s preference. Because of a better size match,
this anastom osis is technically easier than the proximal one with
the hypopharynx. This step should be perform ed prior to the
microanastom osis, because once blood ow is reestablished the
ap increases in size and volume and allows the inset of the ap
to the hypopharynx under the perfect amount of tension.

Patient Positioning
The patient is prepped supine on the operating table, exposing
and draping the abdomen.

Raising the Flap
Step 1
An upper midline incision, from below the xiphoid to just above the
umbilicus with dissection going through the abdominal wall layers
to reach the peritoneal cavity, is used for exposure (Fig. 22.2).
The transverse colon and stomach are retracted superiorly,
isolating the jejunum. The ligament of Treitz de nes the apex
of the small bowel mesentery in the left upper quadrant. The
jejunum is followed distally from the ligament for approximately
40 cm, where the second or third branch of the SMA provides a
long arterial pedicle. Harvesting from this site facilitates easier
intra-abdominal bowel re-anastomosis, and enables the procure-
ment of a second segm ent of jejunum without proxim al ischem ic
complications should the rst ap fail.
Step 2
The bowel is transilluminated and a suitable vascular pedicle is
selected (Fig. 22.3).
Step 3
The proxim al segm ent of the jejunum is m arked with a stitch
(Fig. 22.4) to ensure isoperistaltic anastomosis of the jejunal ap
for the pharyngolaryngectomy reconstruction.
Fig. 22.2 The upper abdominal midline incision.1

22 Jejunal Flap Reconstruction for Circumferential Pharyngolaryngectomy Defects
261
Fig. 22.3 Transilluminated jejunum showing the SMA vascular arcade.
Fig. 22.4 Suture (white arrow) indicating the proximal end of the jejunum.

262
II Reconstructive Flaps A-to-Z
Fig. 22.5 The white arrow indicates the vascular pedicle.
Fig. 22.6 Emptying and clamping the jejunum. 1, Jejunum; 2, duodenal jejunal exure; 3,
rst jejunal branch; 4, second jejunal branch; 5, third jejunal branch.1

22 Jejunal Flap Reconstruction for Circumferential Pharyngolaryngectomy Defects
263
Fig. 22.7 Jejunal ap isolated on its vascular pedicle. 1, Jejunum; 2, duodenal jejunal
exure; 3, rst jejunal branch; 4, second jejunal branch; 5, third jejunal branch.1
Fig. 22.8 The bowel is divided.

264
II Reconstructive Flaps A-to-Z
Fig. 22.9 Jejunal anastomosis to the hypopharynx using the intestinal stapler.
Step 8
Arterial supply is reestablished by end-to-end anastomosis to a
suitable artery in the neck. Cranially, the superior thyroid or fa-
cial artery and caudally the inferior thyroid artery or transverse
cervical artery. Venous drainage is provided by end-to-side anas-
tomosis with the internal jugular vein or an end-to-end anasto-
mosis with a suitably sized side branch. The pedicle vein is usually
large and selection of an appropriately sized recipient vein is im -
perative for a successful anastomosis. On completion of the anas-
tomosis, spontaneous peristalsis should be visible.
Step 9
If possible, the proxim al anastom osis w ith the hypopharynx
can be perform ed w ith the intestinal stapler (Fig. 22.9), but
ow ing to the inherent size discrepancy, the antim esenteric
border of the jejunum usually needs to be incised and sh-
m outhed to facilitate a water-tight proxim al anastom osis. If
the intestinal stapler cannot be used then a double-layer clo-
sure should be perform ed using a tapered needle. The rst
layer is a full-thickness bite of all layers of the bowel and the
second layer includes the serom uscular layer to secure the
anastom osis.
Step 10
The abdom inal jejunum is re-anastom osed with an intestinal
stapler, and the m esentery is carefully closed with interrupted
sutures to prevent hernia formation (Figs. 22.10 and 22.11).

Postoperative Care

●
The patient is kept warm and well hydrated, and urine out-
put is carefully monitored in a surgical high-dependency
unit.

●
Nasogastric intubation is used to decompress the stom ach,
with nasogastric feeding started following the commence-
ment of abdom inal bowel sounds in the postoperative
period.

●
Barium studies are performed between the 7th and 10th
days postoperatively, and if there are no radiographic or
clinical anastomotic leaks, then oral diet is commenced on
the advice of the specialist speech pathologist.

●
If the jejunoesophageal anastomosis is above the tracheos-
toma, then a primary tracheoesophageal puncture is per-
formed and a large bore nasogastric tube is inserted. If the
anastomosis is at or below the tracheostoma then a few
months later a secondary tracheoesophageal puncture is
performed.

●
These patients usually have a total thyroidectomy and thus
a partial parathyroidectomy and therefore have problems
with calcium levels postoperatively, which does impinge
on bowel motility.

Important Anatomical
Structures
Raised with the ap:

●
Vascularized segment of jejunal conduit

22 Jejunal Flap Reconstruction for Circumferential Pharyngolaryngectomy Defects
265

Clinical Perspectives
Since the rst report in 1959 the jejunal free ap has remained
the de facto standard for pharyngolaryngectomy reconstruc-
tion. It is used in the treatment of circum ferential esophageal
defects secondary to esophageal or laryngeal cancer, trauma,
and pharyngoesophageal stricture resulting from surgery or
radiation therapy.

Flap Variations
The entire antim esenteric border can be longitudinally divided,
providing a large mucosal ap.

Hints and Tips
1. A segment of the jejunum (buoy ap) can be brought out
along the neck incision for m onitoring and ligated on the ward
usually on postoperative day 3 to 5 (Fig. 22.12). Although not
highly valuable for ap salvage due to the low ischemic toler-
ance of the jejunum , it does notify the surgeon of ap death
and the need for a replacement jejunal free ap.
2. Chang et al., in their review of 168 free jejunal reconstruc-
tions, reported the incidence of proxim al stula formation
was lower in patients who had a two-layered repair than in
patients who had a single-layer repair.
3. Moradi et al., in their 10-year review, recommended
“waterproo ng” the jejunum with a prophylactic m uscle-
only pectoralis major ap in all patients previously exposed
Fig. 22.10 Re-anastomosis of the abdominal jejunum with the intestinal stapler.
Fig. 22.11 Closure of the mesenteric surface of the jejunum.

266
II Reconstructive Flaps A-to-Z
to radiotherapy. In their series no patients developed a stula
if the jejunum enteric anastom osis with the hypopharynx or
esophagus was covered with the pectoralis major muscle.
4. The jejunum needs to be put in in moderate tension to avoid
the risk of folding and functional dysphagia.
Suggested Further Reading
Chang DW, Hussussian C, Lewin JS, et al. Analysis of pharyngocutaneous s-
tula following free jejunal transfer for total laryngopharyngectomy.
Plast Reconstr Surg 2002;109:1522–1527
Katsaros J, Banis JC, Acland RD, Tan E. Monitoring free vascularized
jejunum grafts. Br J Plast Surg 1985;38:220–222
Moradi P, Glass G, Atherton D, Spiers A, Majithia A, Co ey M, et al. Recon-
struction of pharyngolaryngectomy defects using the jejunal free
ap: A 10-year experience from a single reconstructive centre. Plast
Reconstr Surg 2010;126(6):1960–1966
Roberts RE, Douglas FM. Replacement of the cervical oesophagus and
hypopharynx by a vascularised free jejunal autograft. Report of a
case successfully treated. N Engl J Med 1961;264:342–344
Seidenberg B, Rosenak SS, Hurwitt ES, et al. Im mediate reconstruction
of the cervical esophagus by a revascularized isolated jejunal
segm ent. Ann Surg 1959;149:162–171
Figure Credits
1. Strauch B, Yu HL. Atlas of Microvascular Surgery: Anatomy and Oper-
ative Approaches. 2nd ed. New York, NY: Thieme; 2006
Fig. 22.12 Pharyngolaryngectomy defect reconstructed with jejunal free ap with monitoring buoy ap.

267
Design, Principles, and Variations of
Keystone Flaps
Michael W. Findlay, Gordon K. Lee, and Felix C. Behan
23

Introduction
An explosion of advances in microvascular surgery, free tissue
transfer, and composite tissue allotransplantation has dominated
the last few decades of reconstructive surgery. In this milieu,
locoregional reconstruction has been de-emphasized in train-
ing despite the often outstanding outcom es that can be achieved
through this low-m orbidity approach to reconstruction. A prac-
ticing m icrosurgeon can function e ectively with expertise in 20
to 30 free tissue transfer techniques by using a single technique
for multiple di erent defects with similar defect characteristics.
However, over 500 named locoregional aps have been described
for speci c indications in various regions of the body, and devel-
oping expertise in this spectrum of ap techniques is challenging.
The keystone ap is unique am ong locoregional aps because it
demonstrates a high capacity for adaptation. The design, blood
supply, and method of mobilization can all be modi ed to meet
the needs of the defect and the available donor tissue in various
regions of the body. This adaptability increases the usefulness of
the ap and provides the surgeon with experience in advance-
ment, transposition, rotation, and perforator-based reconstruc-
tion with this single technique. The simple, reliable nature of this
ap has been established over its nearly 20-year history, which
has seen it adopted in many countries worldwide.
The keystone ap was invented by Felix Behan as early as
1995, but was rst described by him in 2003. Although initially
called the arc ap, it was subsequently renam ed based on its sim -
ilarity to the keystone of archways (Fig. 23.1).
Behan developed the keystone as the culmination of his early
research into the blood supply of the skin and his signi cant
experience with fasciocutaneous aps during clinical practice in
Melbourne, Australia. His vascular studies in 1972 and 1973 includ-
ed the identi cation of the deep inferior epigastric perforator (DIEP)
supply to lower abdominal skin, among others (Fig. 23.1), and ulti-
mately led him to develop the concept of the angiotome (the angio-
tome is a clinical concept with an area of skin supplied by random
vessels; the design must be con ned to the longitudinal limits of the
dermatomal mark out and not cross them transversely), although
di erent conceptually to the angiosome concept developed by Taylor
and Palmer (the origin of Taylor’s work on angiosomes is based
on cadaver investigations). Fifteen years later (also in Melbourne,
Australia), it laid the foundation for his functional understanding of,
and preference for, islandized aps. Through an extensive caseload
and long experience, he adapted existing island aps, leading to the
development of the keystone ap and the evolution of the keystone
island ap (KIF) principles upon which all keystone aps and their
variants are based. These principles share similarities with freestyle
free ap surgery, but are adapted to minimize potential injury to
the vascular supply and the needs of locoregional (versus free) ap
reconstruction. We seek to highlight the similarities and di erences
of these approaches in this section before examining the use of the
keystone ap, its variants, and the guiding keystone principles upon
which such locoregional ap use is based (Fig. 23.2).

Classif cation
The keystone ap is readily adaptable and, as a result, can be clas-
si ed in a number of ways.

Degree of Islanding
Islanding is the process of circumferential division of a given
piece of tissue. In fasciocutaneous aps, this can refer to the skin,
the fascia, or both. The typical approach is full circum ferential
islanding of the skin and fascial islanding as required to mobi-
lize the ap, thereby minimizing the risk of inadvertent injury
to the vascular supply and/or neurovascular structures. Islanding
of the skin provides a potential bene t to cutaneous perfusion
(approximately 3 to 5% increase) as supported by our own studies
of island aps and those of others, but this potential bene t must
be weighed against the additional scar burden from islanding. It
is important to note that the human eye nds it di cult to recog-
nize unusual or infrequently seen patterns, especially when ele-
ments of them match their surroundings, just as the curvilinear
Fig. 23.1 The keystone  ap is named based on the similarity of its shape 
to the keystone of Roman archways.1

268
II Reconstructive Flaps A-to-Z
elasticity. As soon as an additional type of mobilization is added,
the amount of tissue to assist closure increases dramatically. Such a
modi cation requires greater experience to plan, but is supported
by the robust nature of the keystone ap, which permits adapta-
tions on the y without signi cantly increased risk of ap failure.

Single/Dual Flaps with/
without Skin Grafts
The unilateral design of the keystone ap, relative to the defect, read-
ily permits single or double keystone ap closure. Double keystone
ap closure may be by direct symmetrical apposition (Fig. 23.3b)
or by opposing transposition/advancement (Fig. 23.3c). Skin graft-
ing of the secondary defect may be undertaken if direct closure is
likely to be too tight (Fig. 23.3d) or as part of the preoperative plan
in areas of minimal surrounding skin (Fig. 23.3e).
One useful way to classify these aps involves a sequential
approach that progressively mobilizes more tissue. The result is
four main types of keystone ap.
shape of keystone aps matches can be designed to match biolog-
ical curves. This may explain part of the reason that fully islanded
keystone aps can hide relatively well compared to more simple
geometric shapes. Furthermore, islanding permits ap inset with
very even, physiological tension to minimize pin-cushioning.

Type of Mobilization
Keystone aps are relatively unique among locoregional aps in
that they demonstrate multivectorial movement—that is, they uti-
lize the viscoelastic properties of the skin via creep as well as being
able to be mobilized in numerous ways. The typical mobilization is
by advancement with V-Y closure at the two vertices of the larger
arc. However, one end, or both ends (omega variant; named after
the Greek symbol), may be transposed and their shape adapted to
permit rotation as required by the region. Type 1 aps are the clas-
sical description for the keystone ap and move by simple advance-
ment alone (Fig. 23.3a). The gain in width for wound closure using
this technique is often modest, particularly if the ap-to-defect
width ratio is not greater than 1:1 and if the patient has poor skin
Fig. 23.2 (a) Cadaveric dissection to determine the angiotome for the deep inferior epigastric 
perforators during elevation from the abdominal wall. (b) Arterial and venous injection studies to 
examine the blood supply and drainage conducted by Dr. Behan in 1972. Such studies were the 
theoretical basis for his understanding of perforator-based blood supply to  aps.1
a
b

23 Design, Principles, and Variations of Keystone Flaps
269
Fig. 23.3 Types of keystone  aps. (a) Standard design 
of the keystone  ap showing a minimum of 1:1 ratio 
of defect width to  ap width. Following mobilization of 
the  ap, V-Y closure at the margins reduces the size of 
the secondary defect. The leading edges of the  ap (4
and 5) are then trimmed. (b) Double opposing key-
stone  aps. (c) Yin-yang variant of double opposing 
keystone  aps where opposite ends are transposed to 
close the defect. This version is excellent for  re-creating 
convexity. (d) Keystone  ap inset with skin graft of the 
secondary defect. (e) Transposition variants: similar to 
the yin-yang variant, one or both ends of the keystone 
ap are transposed to close the defect. When one is 
transposed (the white region in this image), the sec-
ondary defect may require skin grafting, especially in 
the lower leg. When both ends are transposed in the 
omega variant, good convexity is produced.1,2
a
b
c
d
e

270
II Reconstructive Flaps A-to-Z
its dissection is too involved and would potentially put the ves-
sel at risk, the approach can be converted to a muscle-sparing
transverse rectus abdom inis (TRAM) ap by taking a piece of the
rectus muscle w ith the vessels. Prior to ap harvest, the most ap-
propriate perforator (or perforators) m ust be decided upon and
direct visualization (including the use of microvascular clamps
on these if necessary) is essential to this process. In practice, the
most com mon issue with the blood supply to these aps is in-
adequate venous return and the predominant venous drainage
(via venae com itantes or the super cial inferior epigastric vein
[SIEV]) m ust be determ ined in order to avoid venous congestion
and ap death. Supercharging of the ap through microvascular
anastomosis of an additional vein (e.g., to the thoracodorsal vein)
can address this issue if it occurs.
Keystone ap elevation follows a di erent, but related
approach. It recognizes that every region of skin has cutaneous
vessels and, as evidenced by the DIEP ap, relatively large pieces
of tissue can be supported on relatively small vessels as long as
they are not traum atized and there is su cient venous drain-
age. The skin is incised sharply (with or without full cutaneous/
fascial islandization) while maintaining the main super cial
veins where possible (including the SIEV system ) through blunt
dissection. Where possible, the feeding perforators would not be
visualized speci cally and the ap would be progressively m o-
bilized only until there was su cient mobility to permit defect
closure. Avoidance of dissection of the perforators lim its the risk
of damage to them including endothelial dysfunction, a concept
proponents of the muscle-sparing TRAM appreciate well. When
further mobilization is required, the vessels may be followed but
their dissection stops when the defect can be closed and, with
good ap planning, this degree of mobilization is rare. Where
blood supply may be marginal, full cutaneous islanding appears
to help cutaneous perfusion and ensures even tension across the
ap on inset and closure.
The nature of good ap planning usually results in a ap
that is too large for the prim ary defect and m ust be trim m ed,
and this region is m ost com m only the region w ith the m ost
m arginal blood supply (or venous drainage). This “blind” ap-
proach w ith regard to perforator visualization can be unsettling
to the classically trained m icrosurgeon, but the size of the ap
required for defect closure usually ensures the incorporation of
su cient perforators in the absence of previous surgery or in-
jury. The application of classic m icrosurgery principles to key-
stone and related perforator-based island aps (e.g., speci c dis-
section of the arterial and venous supply) increases endothelial
dysfunction and m ay result in increased risk of vascular injury,
ap failure, and hesitance in the future use of these aps. While
m icrosurgery and these keystone principles both seek to lim it
endothelial dysfunction, m icrosurgery requires dissection of
the vessels to facilitate transfer, whereas the keystone approach
can usually avoid this in m ost cases. This m akes the keystone
and related aps easier to perform and lim its dissection (and
additional injury to the patient), but heightens the need for good
ap planning. On this basis, we encourage surgical trainees or
surgeons w ishing to expand their arm am entarium to plan and
draw out a keystone (or variant) ap for every fasciocutaneous
reconstructive case and thereby increase their skill w ith key-
stone ap planning.

Vascular Pedicle
The classi cation of keystone aps has evolved to incorporate
the nature of the predom inant arterial supply to the ap, thereby
assisting description and dissemination of the technique, par-
ticularly in keystone variants as used in head and neck surgery.
Importantly, this does not mean that the pedicle is speci cally
dissected, thereby putting the pedicle at risk of iatrogenic injury.
The presence of the pedicle can be con rm ed by careful blunt
dissection, but this usually treats the surgeon’s concerns rather
than the patient’s. One of the KIF principles is that, where pos-
sible, seek blood supply from both arterial and neurovascular
sources (conjoint supply). This maximizes blood supply and the
potential for keystones to be designed with axial vessels with-
in the ap because vessels and cutaneous nerves often follow
similar courses. For this reason, the dermatomes act as a useful
aide-memoire to identifying the axis of the aps without specif-
ic need for understanding the underlying perforator anatomy in
signi cant detail. The major exception to this approach is on the
back where the dermatomes are arranged transversely, but the
marked longitudinal arrangement of m ost structures in the cen-
tral back facilitates only lateral ap m ovem ent; therefore, aps
in this region should be longitudinal. The m ain arterial supply
to keystone aps is typically perforator-based (keystone perfora-
tor island ap [KPIF]), but depending on the region of the body,
direct vessels may be involved (e.g., in the scalp, groin). Vessels
are typically not seen during keystone ap dissection, but knowl-
edge of the main perforators, the safe principles of elevation, and
stepwise attainm ent of experience lead to increased con dence
with keystone reconstruction.

Keystone Principles of
Flap Elevation versus
(Freestyle) Free Flap
Surgery
The abdom en is one of the m ost closely studied regions in the
body in term s of cutaneous blood supply and the ability to de-
velop locoregional or free aps based on these vessels. It is well
understood by the m ajority of reconstructive surgeons as a par-
adigm in evidence-based, perforator or direct vessel supported
ap elevation. For this reason, it is a useful area to discuss the
fundamental di erences between the keystone principles of
ap elevation and those routinely applied in free tissue transfer
(including freestyle free aps). In DIEP aps, the ap is elevated
on a speci c perforator or perforators based on intraoperative
assessment of the dominant supply to the ap with or without
preoperative (e.g., computed tomography angiography [CTA])
and/or intraoperative imaging (indocyanine green uorescence
microscopy). The purpose of this approach is to limit morbid-
ity of the anterior abdom inal wall by collateral dam age to the
rectus muscle and its segmental nerve supply. To achieve this,
the perforator m ust be skeletonized to follow its course in re-
lation to the rectus m uscle back to the deep inferior epigastric
artery (DIEA) and vein (DIEV). Where the course of the vessel or

23 Design, Principles, and Variations of Keystone Flaps
271
The missing tissue is norm ally resisting the elastic forces pulling
the wound edges apart. For this reason, planning the ap prior to
defect formation can be useful. The ap is marked out to ensure
at least the same keystone ap width (small arc to large arc) as
the defect diameter (Fig. 23.4).
Additional ap width is required if there is signi cant under-
mining of the wound edge to ensure incorporation of su cient
perforators/direct vessels. The orientation of the ap is typical-
ly longitudinal to the lim b and/or following the derm atom es as
an aide-memoire. A thorough understanding of the perforator
anatomy in the region of reconstruction is useful but not essen-
tial for the majority of defects (e.g., understanding that m obiliza-
tion of aps in the limbs is typically best achieved perpendicular
to the long axis of the limb due to the underlying longitudinal
septal supply to the skin; Fig. 23.5).
Step 3: Determine Degree of
Islandization
The m ost com m on approach is to undertake full skin island-
ing through derm is; exam ine the degree of m obility this pro-
vides (Fig. 23.6). If insu cient for defect closure (Fig. 23.7), the
fascia along the long arc of the ap is divided (while preserv-
ing subcutaneous structures). This perm its bipedicled fascial
m ovem ent. If further m obilization is required, the fascia is fully
islanded (Fig. 23.8). With proper design of the ap, it is very
rare to need to follow perforators back through the structures
they perforate (e.g., m uscle or septae). Such dissection risks
dam aging the often very delicate blood supply of these aps,
resulting in ap necrosis. Typically, w hen aps fail, it is in the
setting that the predom inant perforator was dissected, and
therefore, this is usually avoidable. In the case presented, dis-
tal transposition of the ap was necessary to facilitate wound
closure (Fig. 23.9).

Design and Principles of
Elevation
Step 1: Assess Defect, Pathology,
and Available Vascular Pedicles
and Tissue
The need for a comprehensive assessment of the defect cannot
be understated. Where possible, obtainment of adequate margins
(including the potential need for wide local excision) or thorough
debridement with absence of pathogens on culture is vital to the
success of any ap, whether keystone or otherwise. Care should
be taken not to “create an island of excellence in a sea of medi-
ocrity.” The defect size is assessed including whether there are
any additional areas of devitalized tissue requiring debridem ent.
Then assessment of the remaining locoregional tissue with intact
vasculature is undertaken as the basis for keystone ap elevation
(or one of its relatives). This involves the pinch test, where the
available local tissue is assessed by pinching it together between
the ngers and thumb. Proper assessment of the cutaneous vascu-
larity includes an assessment of the venous drainage and preser-
vation of local veins. Single small perforators can supply relatively
large aps, especially in the head and neck. Previous radiotherapy
is not a contraindication to keystone ap reconstruction, but extra
dissection may be required to mobilize the tissue ap adequately,
and it is essential to stay in the correct tissue plane to facilitate
dissection and minimize inadvertent injury to vital structures.
Step 2: Mark Out Flap and
Determine the Form of Mobilization
Reconstruction of the defect is based upon the original defect
size (rather than the defect size following skin edge contraction).
Fig. 23.4 A 4 3  7 cm pretibial lesion is marked out ready for excision.

272
II Reconstructive Flaps A-to-Z
Fig. 23.5 (a) The mark out is placed to run 
longitudinally with the limb. (b) Following 
excision, the pretibial defects appears slightly 
larger following excision, here with exposed 
tibia requiring fasciocutaneous coverage. The 
ap is planned as wider than a 1:1 ratio with 
the defect due to the need to cover the convex 
surface of the tibia.
a
b
Fig. 23.6 Full skin islandization is undertak-
en  sharply,  while  preserving  subcutaneous 
structures.

23 Design, Principles, and Variations of Keystone Flaps
273
Fig. 23.7 Following blunt dissection of the subcutaneous structures, some mobility of the  ap is evident, but this 
is insu cient for defect closure.
Fig. 23.8 Full fascial islandization is undertaken through small windows in the subcutaneous tissues to permit 
further mobilization.

274
II Reconstructive Flaps A-to-Z
a
Fig. 23.9 (a) The distal end of the  ap is elevated to permit transposition of the end for easy closure over the ex-
posed tibia of this pretibial defect. (b) Following full skin and fascial islanding and transposition of a small amount 
of the distal end of the  ap, the defect is easily able to be closed.
b
Step 4: Maintain Subcutaneous
Neurovascular Structures
Where Possible
Following sharp dissection through the skin, the subcutane-
ous tissues are preserved as much as possible by gentle blunt
dissection. This preserves the subcutaneous nerves and, very
importantly, the venous drainage for the aps (Figs. 23.7 and
23.8). Sequential, selective ligation of veins is often necessary for
su cient mobilization of aps, but preservation of venous drain-
age is another keystone principle that maxim izes ap survival.
The underlying fascia can be accessed through small windows
in the subcutaneous tissue followed by careful scissor-based
mobilization.

23 Design, Principles, and Variations of Keystone Flaps
275
tension across the entire ap, an important keystone principle to
minimize the risk of focal/tip necrosis of the ap.
Step 7: Determine Whether
an Additional Small Skin
Graft Is Necessary to Prevent
Supraphysiological Tension
Tension is a normal physiological state in skin. Upon wounding
or incision, the skin edges pull apart, because they can no longer
resist the elastic pull of the surrounding skin. Therefore, the ideal
reconstruction should import su cient tissue to re-create natural
physiological tension. Over-reconstruction ( ap too large) leads
to poor skin draping and, in our experience, risks pin- cushioning.
Under-reconstruction (wound tension too high) risks wound
dehiscence and broad, potentially hypertrophic scarring. The role
of physiological tension in facilitating ap survival has not been
adequately assessed, but this keystone principle has aesthetic
relevance. Usually, there is redundant ap tissue at the leading
edges that is trim med and can be used for sm all skin grafts if nec-
essary at the secondary defect site (Fig. 23.11). The V-Y points can
then be closed (Fig. 23.12a) and strategic mattress sutures used
to even out tension before nal wound closure (Fig. 23.12b).
Step 8: Assess Need for
Postoperative Splinting by Passive
Movement of Nearby Joints
Following wound closure, passive movement of the surround-
ing joints (especially in the limb) is an excellent gauge of the
need for postoperative splintage. Where additional skin grafts
were required to minimize supraphysiological tension, splintage
can have a useful role. The m anner of splintage can be either
solid (e.g., backslap or Helical splint) or soft (e.g., Robert-Jones
Step 5: Release Tourniquet If Used
and Assess Flap Vascularity
The use and tim ing of tourniquet release are m atters of person-
al surgical preference. Prior to wound closure, it is often use-
ful to release the tourniquet in keystone ap surgery for two
m ain reasons. It allows for appropriate hem ostasis, thereby
m inim izing the risk of hem atom a form ation and reoperation.
The second bene t is that observation of the ap during tour-
niquet release often dem onstrates the site of the predom inant
perforator(s) as the starting spot for creeping erythem a that
usually then extends to the periphery of the ap. This inform s
the surgeon about the presence and site of the perforator(s)
w ithout the need for their speci c dissection. Such knowledge
is very useful as cases, and the keystone aps used, becom e
m ore complex.
Step 6: Utilize Creep, Place
Strategic Mattress Sutures, and
Undertake Continuous Closure to
Produce Even Physiological Tension
Creep is a very useful tool in keystone ap surgery. Creep is de-
ned as the capacity for a m aterial (e.g., skin) to elongate when
placed under constant tension. In practice, this means that non-
permanent sutures are placed across the widest point of the de-
fect and secondary defects as soon as is practical (Fig. 23.10).
Over the next 10 to 15 m inutes of strategic m attress or corre-
sponding deep suturing, the skin elongates along the axis of the
tension through both biological and mechanical creep. As a re-
sult, the wound becomes progressively easier to close. Strategic
suturing has a similar, but less marked, e ect, with the major-
ity of the heavy lifting being undertaken by the initial tension
or block and tackle sutures that are removed following wound
closure. A continuous suture around the ap helps to ensure even
Fig. 23.10 Temporary tension sutures are placed across the  ap to encourage creep from each of the corners and 
across the middle of the primary and secondary defects.

276
II Reconstructive Flaps A-to-Z
Fig. 23.11 (a) Redundant  ap tissues on the leading edge of the  ap are marked ready for their removal. (b) Fol-
lowing removal of the redundant tissue, the  ap shape is well-suited to the geometry of the defect and the redun-
dant skin can be used as a full-thickness skin graft if wound tension is supraphysiological following  nal wound 
closure. A small graft placed over the site of maximal tension for the secondary defect can be very e ective and 
does not signi cantly worsen appearance as it is locally matching tissue.
a
b
bandage). Each has its relative merits. In general, early mobiliza-
tion is common following keystone ap surgery, thereby facilitat-
ing its use in ambulatory care settings.
Step 9: Document the Flap
Type, Outline, and Movement
to Facilitate Re-Operation, if
Required
The anticipation of re-operation and planning for future events
is highly useful in all ap surgery. Where incomplete excision oc-
curs, re-operation will require an understanding of the type of
ap and its means of mobilization. This is particularly important
if part of the ap needs to be included in the re- excision margin.
Furthermore, existing aps can be mobilized again to close areas
of recurrence. Due to the unusual shape of the keystone ap, it
can be di cult to de ne the keystone ap scar, especially in the
elderly. Incorporation of operative and postoperative photos or
diagrams is invaluable to re-operative ap surgery.

Clinical Perspectives
The keystone ap can be used in almost every region of the body
for fasciocutaneous reconstruction. It is particularly useful in