Phẫu Thuật Tạo Hình Grabb & Smith’s (Bản Cập Nhật – Kevin C. Chung)

Thumb Fingertip Defect
The thumb is responsible for 40% of total hand function, enabling pinching, grasping, and opposition.
Reconstruction of a defect on the thumb should aim to provide adequate length, a nonpainful tip,
sensation, mobility, and stability to oppose the other fingers.
The ulnar contact side of the thumb is the most important tactile area on the hand, enabling movements
like key pinch and three-point pinch grip. Thus, restoration of the sensory function is vital for normal
hand function and grip strength.
A defect without any bony exposure that affects less than half of the finger pulp can heal by secondary
intention. Secondary intention results in excellent contour, consistency of the finger pulp, and satisfactory
return of sensory function. However, defects that are larger, volar oblique, and leave exposed bones will
require flap coverage. The location and size of the defect will influence the flap selection (Table 69.3).
TABLE 69.3
Flap Options for Thumb Fingertip Reconstruction
Flap
Indication
Contraindication
Moberg flap
Thumb amputation distal to the interphalangeal
joint, especially for volar oblique thumb tip
defects.
Distal volar defects of the thumb, up to 1.5 cm in
longitudinal diameter.
Extensive soft tissue defects with a lack of volar
soft tissue of the thumb.
First dorsal
metacarpal artery
(DMCA) flap
Extensive volar or ulnar defect of the thumb that
cannot be treated with a Moberg or digital island
flap.
Dorsal or radial defect of the thumb with tendon
or bony exposure.
Injury to the dorsal carpal circulation.
Significant loss of the dorsal skin.
Neurovascular
heterodigital island
flap
Extensive volar or ulnar defect of the thumb that
cannot be treated with a Moberg or first DMCA
flap.
Dorsal or radial defect with tendon or bony
exposure that is not amendable to first DMCA
flap.
Injury of the digital artery of the donor or
adjacent fingers.
Patients with peripheral vascular disease, heavy
smoking or vasculitis that affects the vasculature
of the finger.
Negative Allen test of the donor finger.
Reversed dorsal ulnar
or dorsal radial artery
flap
Dorsal or radial defect of the thumb with tendon
or bony exposure.
Extensive injury of the dorsal skin over the
metacarpophalangeal joint of the thumb.
Severe injury that involves the volar and dorsal
areas of the thumb that injure the flap pedicle.
Toe pulp transfer
Large volar or ulnar pulp defect that is not
amenable for an innervated locoregional flap.
Multiple finger injuries, in which the transfer of
toe pulp allows conservation of the remaining soft
tissue coverage.
For younger patients who are nonsmokers and are
free of vascular disease.
Patients medically unfit or unwilling to undergo
microvascular surgery.
Patients with peripheral vascular disease.
Volar or ulnar side defects are best reconstructed by the Moberg flap. A Moberg flap can advance distally
by 1.5 to 2 cm without causing flexor contracture (Figure 69.1). A Moberg flap reconstruction can achieve
excellent sensory restoration, maintaining contour and suitable fingerprint pattern for friction. However,
larger defects that require more than 2 cm of flap advancement are not suitable for reconstruction using
the Moberg flap because it requires a more ancillary procedure to diminish flexion contracture of the
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thumb interphalangeal joint such as division of the proximal skin bridge for additional advancement.
Thus, larger defects should be reconstructed with the first dorsal metacarpal artery (DMCA) flap because
it provides more soft tissue and can immediately restore sensation by including a branch of the
superficial radial nerve (Figure 69.2). 31 If using a first DMCA flap is not possible because of the extent of
the injury, an innervated heterodigital island flap from the long or ring finger is an alternative option.
However, an innervated heterodigital island flap requires more vascular pedicle dissection into the palm.
Furthermore, the use of this flap causes a loss of sensation in the donor finger and a higher rate of venous
congestion than with a first DMCA flap. 32,33 Both the first DMCA flap and innervated heterodigital flap
will cause dual sensation, requiring cortical reeducation on behalf of the patient to achieve sensory
reorientation within a few years. 31,32,34
FIGURE 69.1 A volar oblique amputation of the thumb was left to heal by secondary intention. A, B. Patient presented with a
painful scar and unaccepted thumb appearance. C. A Moberg flap is outlined to reconstruct the finger pulp of the thumb. D. The
bilateral neurovascular bundles were included to provide an innervated finger pulp reconstruction. Note the bilateral proper
digital nerves were included with the flap (arrow). E, F. A Moberg flap was inset with slight interphalangeal joint flexion of the
thumb.
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FIGURE 69.2 A, B. Post wide excision of the subungual melanoma at the nail bed of the left thumb with sentinel lymph node
biopsy. C. First dorsal metacarpal artery (DMCA) flap for reconstruction of a bony exposure defect at the dorsal of the distal
phalange of the thumb. D, E. The pedicle of the first DMCA flap is identified (arrows). Note the pedicle was in the subfascial
layer of the first dorsal interosseous muscle. F, G. The first DMCA flap was transposed to cover the defect. The flap provided
good, pliable, and color-matched skin on the dorsum of the thumb.
Locoregional flaps are not suitable for reconstructing volar or ulnar defects that are accompanied with
extensive injuries to the hand. Cases with extreme injury to the hand are an indication for the use of a
distant flap or microvascular free tissue transfer. However, the distant flap has some disadvantages
including bulky tissue, nonglabrous skin, insensate flap, and prolonged immobilization. Thus,
microvascular glabrous skin transfers, such as toe pulp transfers or medial plantar flaps from the foot, are
more advantageous than distant flaps. 30,35-38 Toe pulp transfers are preferred over medial plantar flaps
because they can provide a sensate flap. 36
In the dorsal or radial areas of the thumb, sensory restoration is not essential. A versatile option for
reconstructing defects in these areas is the reverse homodigital dorsal ulnar or dorsal radial flap, except in
cases involving crushed or avulsion injuries of the thumb. 39,40 This flap is based either on the dorsal ulnar
artery or the dorsal radial artery. The reversed dorsal ulnar artery flap provides soft tissue from the ulnar
side of the thumb over the metacarpophalangeal area and first webspace. This flap should only use less
than 2 cm of skin. 40 Harvesting a larger flap will use the skin of the first webspace, causing contracture of
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the webspace. Instead, a reversed dorsal radial artery flap provides a larger skin paddle that can measure
up to 4 × 3 cm in dimension. 39
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Dorsal Hand Defect
Reconstructing a dorsal defect of the hand should aim to cover tendinous elements and exposed bone, as
well as obtain thin and pliable coverage that facilitates early mobilization. Locoregional fasciocutaneous
flaps can reconstruct medium-sized defects that are less than 6 to 7 cm in width. However, locoregional
fasciocutaneous flaps can cover larger defects but will require a larger skin paddle from the flap, which
will leave a conspicuous skin graft scar. Therefore, free fasciocutaneous flaps are used to reconstruct
defects that are larger or more complex and that require more tissue incorporation such as bone, nerve,
and tendon.
Medium-sized defects of the hand should be reconstructed using locoregional fasciocutaneous flaps,
which include ulnar or radial forearm flaps, posterior interosseous flaps, dorsal ulnar artery flaps, and
forearm perforator flaps. Indication for the use of a certain flap depends on the location of the defect
(Table 69.4). The donor site morbidities of the ulnar or radial forearm flaps are greater than that of the
perforator forearm flap, which includes tendon exposure, dysesthesia, and noticeable scarring after skin
grafting. Furthermore, the harvesting of ulnar and radial forearm flaps sacrifices one of the major vessels
of the hand, making posterior interosseous flaps, dorsal ulnar artery flaps, or forearm perforator flaps
more preferable options.
TABLE 69.4
Flap Selections for the Dorsal and Volar Surface of the Hand and Forearm
Flap
Indication
Contraindication
Posterior
interosseous
flap
The
defect
is
located
at
the
metacarpophalangeal joint, first webspace
and/or the radial palm
Severe injury or high-energy fractures of the distal third of
the forearm that will affect the competency of the posterior
interosseous artery and anterior interosseous artery
anastomosis.
Ulnar
perforator flap
Defect on the dorsal or volar wrist and the
dorsum of the distal hand.
Defect at the cubital fossa or the distal
humerus.
Injury to the adjacent perforators that prevent an adequate
arc of rotation to cover the defect.
Radial
perforator flap
A defect of the dorsal or volar surface of the
hand that is proximal to the base of the
proximal phalanges of the digits
The volar or dorsal defect of the distal forearm
Significant injury to the distal forearm.
A defect that is distal to the metacarpophalangeal joint.
Microvascular
microangiopathy
(extra
caution
with
smokers).
Infraumbilical
abdominal–
based flap
Mutilated hand injuries that require a large
area of soft tissue coverage.
Complex hand defects in children less than
2 years of age.
Soft tissue defects after high energy injuries or
electrical injuries with damage to one of the
major vessels of the hand.
Soft
tissue
reconstruction
prior
to
microvascular
free
tissue
transfer
(e.g.,
coverage
of
digital
stump
defects
in
preparation for toe-to-hand transfers).
Severely contaminated wounds or active infected soft tissue
that requires wound bed preparation.
Anterolateral
thigh flap
Defects of the upper extremities that include
severe hand and forearm injuries that cannot
be reconstructed with a locoregional flap.
Previous surgeries or injuries affect the viability of the
lateral circumflex femoral artery axis.
Lateral arm
flap
A severe injury to the hand or forearm that
Previous surgeries or injuries on the lateral side of the arm
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cannot be reconstructed with a locoregional
flap.
such as plate osteosyntheses of the humerus, which could
have destroyed the perforators.
Free thenar
flap (glabrous
palmar flap)
Small palmar defect of the hand that measures
up to 2 cm × 10 cm.
Take caution in patients with peripheral vascular disease.
The medial
plantar flap
Medium-sized defects on the palmar area of
the hand. The flap can be harvested to a
maximum of 8 cm × 6 cm of skin.
Patients of advanced age, heavy smokers, and peripheral
arterial disease.
If a defect requires composite structural reconstruction, distant pedicle flaps or free fasciocutaneous flaps
are used. Distant pedicle flaps, such as groin or abdominal-based flaps, can provide a large amount of
soft tissue. However, distant pedicle flaps require more than one surgery, which delays the onset of
rehabilitation. Furthermore, distant pedicle flaps are usually bulky, which requires a secondary
procedure to remove some of the subcutaneous fat. However, distant pedicle flaps are preferred in
mutilated hand injuries, especially in cases involving concomitant vascular injuries of the hand or soft
tissue reconstruction, prior to microvascular free tissue transfers (see Table 69.4).
Free fasciocutaneous flaps are a versatile option for reconstruction because they provide thin and pliable
soft tissue with composite structural reconstruction. With increasing success rates of free flap surgery,
patients can initiate early participation in rehabilitation programs and gain satisfactory hand appearance
and function. Free fasciocutaneous flaps include flaps from many locations, such as anterolateral thigh
(ALT) flaps, lateral arm flaps, superficial circumflex iliac perforator (SCIP) flaps, and medial sural
perforator flaps. 41-44 All of these flaps can be raised by a two-team approach. ALT flaps are advantageous
over the other free fasciocutaneous flaps because the length of the pedicle reaches up to 16 cm. 45 ALT
flaps provide a large surface area of skin that enables composite tissue reconstruction to include the
nerve, tendon, or muscle within the same vascular axis. 46 Harvesting a suprafascial ALT flap will result
in a thin, pliable flap. Furthermore, as an advantage to the patient, the donor site of the flap can be hidden
with clothes.
Lateral arm flaps are thin and pliable with consistent blood supply and usually match in color with the
dorsal side of the hand. If the flap that is harvested is less than 6 to 7 cm in width, the donor site can be
closed primarily. The pedicle of the flap is dissected toward the spiral groove, which varies in length by 7
to 11 cm. 47 The lateral arm flap is a versatile flap that can provide a vascularized nerve graft of the
posterior brachial cutaneous of the forearm. Furthermore, the posterior radial collateral artery extends
branches to supply the lateral epicondyle of the humerus and the tricep tendon. Thus, the lateral arm flap
can be used for composite reconstruction of the bone and tendons.
SCIP flaps and medial sural artery perforator flaps are not used as frequently as the other free
fasciocutaneous flaps. The major disadvantage of the SCIP flap is its short pedicle length, which is around
5 cm. 48 Additionally, medial sural artery flaps have limited amount of skin, which makes the flap only
suitable for small-to-medium-sized defects. 41,42
Free or pedicle fascial flaps with skin grafting is another option for reconstructing a dorsal defect of the
hand. One main advantage of fascial flaps is not having to use a skin graft to cover the donor area, which
often leaves a discernible scar. Furthermore, previous literature has demonstrated that it is unusual that
there will be late scar contracture over the fascial flap after skin grafting on the dorsum of the hand. 49,50
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Palmar Hand Defect
Reconstruction of palmar hand defects aims to create high resistance and durability of the reconstructed
tissue, achieve optimal sensory restoration, and provide supple soft tissue for adequate range of motion.
To achieve these goals, palmar skin defects should be reconstructed with glabrous skin. The locoregional
glabrous skins are usually in the zone of injury. Therefore, complicated microvascular free glabrous skin
transfers from the contralateral hand have been described, such as thenar flaps or instep free flaps from
the foot. Free thenar flaps can be raised up to 2 cm in width and 10 cm in length. Thenar flaps can be a
sensate flap by including a small cutaneous nerve originating from the palmar cutaneous branch of the
median nerve. 51 Medial plantar flaps can provide glabrous skin up to 8 cm × 6 cm in dimension with
minimal donor site morbidity. 52-54 These flaps can be harvested as a sensate flap by including the medial
plantar nerve with the flap. However, in larger defects, there is no supple glabrous skin flap that can
provide adequate soft tissue for reconstruction, so nonglabrous skin flaps are used instead.
Posterior interosseous artery (PIA) flaps are considered as the work-horse flap for reconstruction of
defects on the dorsum and volar area of the first webspace and the radial palm. PIA flaps provide reliable
and pliable soft tissue that facilitates thumb mobility (Figure 69.3). In contrast with the dorsum of the
hand, it is not necessary to use a very thin flap. However, for easier tendon gliding, fasciocutaneous flaps
are preferred. Furthermore, using fascial flaps and skin grafts are not suitable in the palmar area because
scar contracture is likely to occur.
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FIGURE 69.3 A. Contracted scar at the first webspace on the left hand. B. The scar was released and the digital nerve
reconstruction was performed. C. A reversed posterior interosseous flap was outlined. The axis of the flap was designed by the
line from the lateral epicondyle of the humerus and the distal ulnar head in full pronation of the forearm. D. The perforators of
the posterior interosseous artery were identified in the intermuscular septum between the extensor carpi ulnaris and extensor
digiti minimi. E. The pivot point was located 3 cm proximal to the distal radioulnar joint. F, G. A reversed posterior interosseous
flap was inset into the first webspace, which provided stable soft tissue for a mobile thumb.
(From Yang, G, Chung, KC. Pedicled forearm flap. In: Chung, KC , ed. Operative Techniques: Hand and Wrist Surgery. 3rd ed. Philadelphia, PA: Elsevier;
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2018:695-702.)
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Management of Nail Bed Injury
The nail is a specialized structure that enhances the sensory perception of the pulp of the finger and
facilitates precise movements such as grasping small objects. Furthermore, the nail is one of the most
imperative, aesthetic features of the hand. Thus, the lost or deformation of the nail can affect both the
appearance and function of the hand.
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Anatomy of the Fingernail
Nail plate
Paronychium—soft tissue fold on the lateral side of the nail plate
Eponychium—soft tissue that is dorsal to the nail plate that is a continuation of the dorsal skin of the
finger. Eponychium creates the matte sheen on the surface of the nail plate
Hyponychium—keratinous mass that serves as a distal attachment of the nail with the pulp skin.
Nail bed—lies under the nail plate
Lanula—white arc line distal to the eponychium
Germinal matrix—nail bed proximal to the lanula, which plays an important role in nail growth.
Sterile matrix—nail bed distal to the lanula
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Subungual Hematoma
The traumatic conditions that affect the nail bed and cause bleeding under the nail plate are described as
subungual hematomas. Subungual hematomas are caused commonly by closed injuries, such as crushing
injuries. If the patient is asymptomatic or the hematoma affects less than half of the nail bed, the patient
can be treated conservatively, including warm compression and the administration of analgesics.
However, if the hematoma affects more than half of the nail bed, it is likely that the nail bed is lacerated
and requires repair. 55 In children, if the nail and perionychium are intact, there is no need for an
exploration and removal of the nail plate. There are many methods of treatment, such as nail bed
exploration and repair, drainage, or conservative treatment. However, the patient’s outcome is similar
regardless of method. 56,57
Furthermore, an X-ray will show if there is fracture of the distal phalanx associated with the subungual
hematoma. If there is fracture of the distal phalanx, the nail plate should be removed for a more thorough
examination of the nail bed and any nail bed laceration can be repaired.
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Nail bed Laceration
If the nail plate is not severely disfigured, it can be soaked in betadine solution and reinserted to the nail
fold as a stent after initial treatment. Reinserting the nail plate will prevent synechiae of the nail fold to
the injured nail bed that will affect the configuration and shining of the nail. If the nail plate is avulsed or
partially detached from the nail bed, the nail plate can be removed to permit a thorough examination of
the nail bed under anesthesia and tourniquet.
Under magnification, the nail bed is examined carefully. If there seems to be a germinal matrix injury,
bilateral incisions on the eponychium are made and the nail fold is elevated to explore the germinal
matrix. The nail bed needs to be repaired with 6-0 or 7-0 absorbable monofilament sutures. If there are
stellate lacerations to the nail bed, conservative debridement is required to preserve the small pieces of
the nail bed as much as possible, followed by a meticulous repair.
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Nail bed Avulsion
Nail bed avulsions can result in the detachment of the nail bed from the distal phalangeal periosteum. If
the nail bed can be recovered, then it can be sutured with the fine absorbable monofilament suture.
However, if the nail bed is partially avulsed from the distal phalanx and it leaves the small defect on the
nail bed, the remaining nail bed can be undermined from the periosteum and advanced to close the
defect. With severe nail bed avulsion that precludes primary nail bed advancement and repair, a nail bed
graft can be harvested from the big toe for reconstruction. After the repair, a nail plate or silicone sheath
can be inserted in the nail fold to act as a splint. The nail plate needs to be secured on the hyponychium
and paronychium with 5-0 nylon suture, which can be removed 3 to 7 days after surgery.
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Acknowledgments
The work was supported by a Midcareer Investigator Award in Patient-Oriented Research (2 K24-
AR053120-06) to Kevin C. Chung. The content is solely the responsibility of the authors and does not
necessarily represent the official views of the National Institutes of Health.
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Questions
1. According to the volar V-Y flap approach, which one is correct?
a. To facilitate flap mobilization, the flap is undermined in the subcutaneous plane until it
reaches the distal interphalangeal joint (DIP) joint.
b. The blood supply perforates the volar digital artery, which lies on both sides of the flap
c. A volar oblique defect is an ideal injury to use this flap.
d. To accommodate a large defect of the fingertip, the apex of the triangular flap should extend
through the DIP joint crease.
e. Flap should be inset by loose suturing to the edge of defect, especially to the nail bed, to
prevent hook nail deformity.
2. A patient with a 5 × 12 cm avulsion wound on the dorsum of the forearm with extensor tendon
exposure. Wound exploration revealed avulsion of the superficial radial nerve with a 7 cm nerve
gap. The surgeon plans to cover the defect with lateral arm free flap with vascularized nerve
grafting. Which nerve can be included with the flap to provide a vascularized nerve graft?
a. Lateral cutaneous nerve of arm
b. Lateral cutaneous nerve of forearm
c. Medial antebrachial cutaneous nerve
d. Superior lateral brachial cutaneous nerve
e. Posterior antebrachial cutaneous nerve
3. A 30-year-old man suffered a crushing injury to his right hand and forearm. The X-rays revealed a
comminuted fracture of distal radius and ulna. His thumb was avulsed. What should be the initial
method of reconstruction for the avulsion injury of the thumb as shown in Figure 69.4?
a. Posterior interosseous flap
b. Infraumbilical abdominal-based flap
c. Reversed radial forearm flap
d. First DMCA flap
e. Toe-to-hand transfer
4. A 40-year-old male had an electrical injury to his right hand. He lost his little finger and the dorsal
skin of his middle and ring finger. The injury left the extensor tendon of his middle finger exposed,
as well as the bare phalangeal bone (Figure 69.5). A segment of the extensor tendon of the ring finger
was also lost. What is the most appropriate choice for reconstructing this defect?
a. Radial forearm flap
b. First DMCA flap
c. Posterior interosseous flap
d. Pedicle groin flap
e. ALT free flap
5. A 20-year-old man was involved in a motor vehicle crash. He lost the digital pulp of his left thumb,
as shown in Figure 69.6. Which flap will provide the best function and sensation for this patient?
a. Visor flap
b. Littler flap
c. Thenar flap
d. Moberg flap
e. Cross-finger flap
1. Answer: e. A volar V-Y advancement flap is best suited for dorsal oblique or transverse fingertip
injuries or transverse amputations with a sufficient amount of remaining tissue. The vascular
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supplies of the flap come from the terminal branches of the digital arteries emerging from the digital
transverse arch in the subcutaneous plane. Flap outlines should not extend through the DIP because
it will lead to further flexion contracture. To facilitate flap mobilization, the dorsal dissection
proceeds proximally on the periosteum until the flexor tendon attachment is seen. Flap should be
approximated loosely with the defect, especially to the nail bed to prevent hook nail.
2. Answer: b. The posterior cutaneous nerve of the forearm (PCNF) also travels alongside the
posterior cutaneous of the arm, within the lateral intermuscular septum. The PCNF runs through the
intermuscular septum without any innervation to the skin, but ends with innervation to the posterior
forearm skin. The PRCA extends vascular branches to nourish the PCNF. The PCNF can be
harvested as a vascularized nerve graft with a lateral arm flap for reconstruction of any nerve
defects.
3. Answer: b. Reconstructing the thumb is the ultimate goal of reconstruction with avulsion injuries
of the thumb. Toe-to-hand transfer will be performed eventually, but preparing the soft tissue to
accommodate the neothumb is mandatory. According to the mechanism of the injury, a locoregional
flap is located within the zone of the injury. Therefore, a distant pedicle flap is the most appropriate
for this patient’s case.
4. Answer: e. The defect is located distal to the proximal interphalangeal joint and the surface area of
the defect is quite large. The defect also needs multiple skin paddles to cover each finger
individually. Therefore, the appropriate flap should be large with multiple perforators, which can be
divided according to the location of the perforators. The ring finger requires an extensor tendon
reconstruction as well. Therefore, an anterior lateral thigh flap can provide a single-stage surgery to
simultaneously cover the defect while reconstructing the tendon. A locoregional flap cannot provide
adequate soft tissue to reconstruct this defect. The pedicle groin flap will need a stage surgery that
precludes early rehabilitation.
5. Answer: d. A Moberg flap and Littler flap can both provide a sensate, soft tissue reconstruction of
the defect. However, the Littler flap requires the patient to retrain the brain to register the sensation
in the new area. Therefore, the Moberg flap is a better option. The other flaps cannot provide a
sensate flap reconstruction.
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FIGURE 69.4 A crushing injury to the right hand, which underwent wound suturing and revision amputation of the thumb and
little finger.
FIGURE 69.5 The postdebridement wounds of an electrical injury to the right hand. After debridement, there was a segmental
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loss of the extensor tendon of the ring finger and bare phalangeal bone exposure of the middle, ring, and little finger.
FIGURE 69.6 A 1.5 cm wide traumatic volar oblique soft tissue defect of the thumb tip.
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Soderberg, T, Nystrom, A, Hallmans, G, Hulten, J. Treatment of fingertip amputations with bone exposure: a comparative study between
surgical and conservative treatment methods. Scand J Plast Reconstr Surg. 1983;17(2):147-152.
Mennen, U, Wiese, A. Fingertip injuries management with semi-occlusive dressing. J Hand Surg (Edinburgh, Scotland). 1993;18(4):416-422.
Lamon, RP, Cicero, JJ, Frascone, RJ, Hass, WF. Open treatment of fingertip amputations. Ann Emerg Med. 1983;12(6):358-360.
Weichman, KE, Wilson, SC, Samra, F, et al. Treatment and outcomes of fingertip injuries at a large metropolitan public hospital. Plast
Reconstr Surg. 2013;131(1):107-112.
Tupper, J, Miller, G. Sensitivity following volar V-Y plasty for fingertip amputations. J Hand Surg (Edinburg, Scotland). 1985;10(2):183-184.
Krishnan, KG. Sensory recovery after reconstruction of defects of long fingertips using the pedicled V flap. Br J Plast Surg. 2001;54(6):523-527.
Foucher, G, Dallaserra, M, Tilquin, B, et al. The Hueston flap in reconstruction of fingertip skin loss: results in a series of 41 patients. J Hand
Surg. 1994;19(3):508-515.
Deglise, B, Botta, Y. Microsurgical free toe pulp transfer for digital reconstruction. Ann Plast Surg. 1991;26(4):341-346.
Trankle, M, Sauerbier, M, Heitmann, C, Germann, G. Restoration of thumb sensibility with the innervated first dorsal metacarpal artery
island flap. J Hand Surg. 2003;28(5):758-766.
Oka, Y. Sensory function of the neurovascular island flap in thumb reconstruction: comparison of original and modified procedures. J Hand
Surg. 2000;25(4):637-643.
Krag, C, Rasmussen, KB. The neurovascular island flap for defective sensibility of the thumb. J Bone Jt Surg Br. 1975;57B:495-499.
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Liu, H, Regmi, S, He, Y, Hou, R. Thumb tip defect reconstruction using neurovascular island pedicle flap obtained from long finger. Aesthet
Plast Surg. 2016;40(5):755-760.
Buncke, HJ, Rose, EH. Free toe-to-fingertip neurovascular flaps. Plast Reconstr Surg. 1979;63(5):607-612.This study demonstrated the results of the
reconstruction of pulp defects with a pulp flap from the big toe (hemipulp) and second toe in six patients. The authors emphasized the fundamental of
reconstruction, replacing like with like, functional, and sensory restoration.
Lin, CH, Lin, YT, Sassu, P, et al. Functional assessment of the reconstructed fingertips after free toe pulp transfer. Plast Reconstr Surg.
2007;120(5):1315-1321.This study was to comprehensively assess the functional outcome of the reconstructed fingertips after free toe pulp transfer.
Free toe pulp transfer was the optimal reconstructive option because it could restore the function, sensibility, and durability of the injured fingers.
Huang, SH, Wu, SH, Lai, CH, et al. Free medial plantar artery perforator flap for finger pulp reconstruction: report of a series of 10 cases.
Microsurgery. 2010;30(2):118-124.
Koshima, I, Urushibara, K, Inagawa, K, et al. Free medial plantar perforator flaps for the resurfacing of finger and foot defects. Plast Reconstr
Surg. 2001;107(7):1753-1758.
Moschella, F, Cordova, A. Reverse homodigital dorsal radial flap of the thumb. Plast Reconstr Surg. 2006;117(3):920-926.
Teran, P, Carnero, S, Miranda, R, et al. Refinements in dorsoulnar flap of the thumb: 15 cases. J Hand Surg. 2010;35(8):1356-1359.
Lin, CH, Lin, CH, Lin, YT, et al. The medial sural artery perforator flap: a versatile donor site for hand reconstruction. J Trauma.
2011;70(3):736-743.
Zheng, H, Liu, J, Dai, X, Schilling, AF. Free conjoined or chimeric medial sural artery perforator flap for the reconstruction of multiple defects
in hand. J Plast Reconstr Aesthet Surg. 2015;68(4):565-570.
Kuo, YR, Jeng, SF, Kuo, MH, et al. Free anterolateral thigh flap for extremity reconstruction: clinical experience and functional assessment of
donor site. Plast Reconstr Surg. 2001;107(7):1766-1771.
Narushima, M, Iida, T, Kaji, N, et al. Superficial circumflex iliac artery pure skin perforator-based superthin flap for hand and finger
reconstruction. J Plast Reconstr Aesthet Surg. 2016;69(6):827-834.
Lakhiani, C, Lee, MR, Saint-Cyr, M. Vascular anatomy of the anterolateral thigh flap: a systematic review. Plast Reconstr Surg.
2012;130(6):1254-1268.
Wei, FC, Jain, V, Celik, N, et al. Have we found an ideal soft-tissue flap? An experience with 672 anterolateral thigh flaps. Plast Reconstr Surg.
2002;109(7):2219-2226.This study reviewed the 660 consecutive patients who underwent ALT flap reconstructions. The authors demonstrated the
versatility of the ALT flap to reconstruction of various defects and with minimal donor site morbidities.
Saint-Cyr, M, Wong, C, Schaverien, M, et al. The perforasome theory: vascular anatomy and clinical implications. Plast Reconstr Surg.
2009;124(5):1529-1544.This vascular anatomic study of the 217 flaps in 40 fresh cadavers demonstrated the direct and indirect linking vessel between
the perforator vessels. Implication of the perforasome theory would facilitate the surgeon understand and precisely design the perforator flaps.
Goh, TL, Park, SW, Cho, JY, et al. The search for the ideal thin skin flap: superficial circumflex iliac artery perforator flap—a review of 210
cases. Plast Reconstr Surg. 2015;135(2):592-601.
Carty, MJ, Taghinia, A, Upton, J. Fascial flap reconstruction of the hand: a single surgeon’s 30-year experience. Plast Reconstr Surg.
2010;125(3):953-962.
Taghinia, AH, Carty, M, Upton, J. Fascial flaps for hand reconstruction. J Hand Surg. 2010;35(8):1351-1355.
Orbay, JL, Rosen, JG, Khouri, RK, Indriago, I. The glabrous palmar flap: the new free or reversed pedicled palmar fasciocutaneous flap for
volar hand reconstruction. Techn Hand Upper Extrem Surg. 2009;13(3):145-150.
Zelken, JA, Lin, CH. An algorithm for forefoot reconstruction with the innervated free medial plantar flap. Ann Plast Surg. 2016;76(2):221-226.
Acikel, C, Celikoz, B, Yuksel, F, Ergun, O. Various applications of the medial plantar flap to cover the defects of the plantar foot, posterior
heel, and ankle. Ann Plast Surg. 2003;50(5):498-503.
Sen, SK, Fitzgerald O’Connor, E, Tare, M. The free instep flap for palmar and digital resurfacing. J Plast Reconstr Aesthet Surg. 2015;68(9):1191-
1198.
Simon, RR, Wolgin, M. Subungual hematoma: association with occult laceration requiring repair. Am J Emerg Med. 1987;5(4):302-304.
Roser, SE, Gellman, H. Comparison of nail bed repair versus nail trephination for subungual hematomas in children. J Hand Surg.
1999;24(6):1166-1170.
Gellman, H. Fingertip-nail bed injuries in children: current concepts and controversies of treatment. J Craniofac Surg. 2009;20(4):1033-1035.
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C H A P T E R 7 0
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Management of Compression Neuropathies of the
Upper Extremity
Loree K. Kalliainen and William B. Ericson, Jr
Key Points
Peripheral nerve compression occurs at more locations than are classically taught. Symptoms may be
vague, and compression can present as motor weakness, deep aching or radiating pain, or numbness,
with symptoms where the nerve ends rather than where it is compressed. Detailed knowledge of
anatomy is crucial to differentiating potential sites of compression.
Diagnosis of peripheral nerve compression may often be achieved with history and physical exam
alone and without the use of electrodiagnostic or radiologic imaging techniques, including
radiographs, MRI, CT scan, and ultrasound.
Recovery after decompression depends on preoperative duration, severity, and secondary
comorbidities such as diabetes, hypertension, hypothyroidism, age, and location(s) of compression.
There is no single decompression technique at the cubital tunnel that has been shown to be superior.
Recovery of index and thumb flexion strength is generally rapid following release of the median
nerve at the pronator.
Ulnar nerve compression at the wrist is more likely associated with soft tissue masses, vascular
anomalies, and anatomic variations than compression at the elbow.
Carpal tunnel syndrome is the most commonly recognized peripheral neuropathy of the upper
extremity and can be safely and effectively treated surgically under local, regional, or general
anesthesia,
Postoperative splinting is generally unnecessary after nerve decompression.
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Nerve Dysfunction Related to Chronic Nerve Compression
Chronic nerve compression causes dysfunction through several mechanisms. 1,2 Enveloping connective
tissues become thickened and fibrotic, limiting nerve glide and impairing vascular supply. Edema
accumulates in the endoneurium, and because there are no lymphatic channels within it to aid in
drainage, microvascular flow is further obstructed. 3 External pressure causes demyelination and axonal
degeneration.
Initial symptoms of nerve compression are paresthesia and deep aches. Progression of compression with
subsequent loss of axons is associated with a consistent loss of sensation, weakness, and eventually
muscle atrophy. 4 If the nerve is decompressed, demyelination can be reversed, and function can improve.
Recovery depends upon duration and degree of compression and damage, secondary factors such as
hypertension, diabetes, and hypothyroidism, and the presence of multiple sites of compression (the
“double crush phenomenon”).
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Diagnosis
Pathologic compression of a peripheral nerve typically affects a named nerve with paired motor and
sensory components, and the combined evaluation of both is critical to determining the source and site(s)
of compression. Mild compression of motor nerves causes muscle weakness, and severe, prolonged
compression causes atrophy. Compression of sensory nerves causes paresthesias (if the nerve innervates
skin) or pain where the nerve ends (e.g., sensory nerve to a joint). The location and timing of symptoms,
their severity, and progression are clues as the location and etiology of the nerve compression. Successful
treatment requires extensive knowledge of nerve anatomy and physiology, as well as an appreciation for
the influence of anatomic and physiologic comorbidities and anatomic variations.
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History
Symptoms are defined by location, character, and timing of sensory disturbance, weakness, and/or pain.
Numbness as a clinical complaint is clearly related to nerve dysfunction and is often the presenting
complaint; it is usually the starting point to establish a differential diagnosis. Paresthesia is painful and
clearly nerve-related. Word choice is important, as doctors often use “numbness” and “tingling”
interchangeably when examining patients, whereas patients with paresthesia may deny having
numbness. Weakness can be caused by compression of motor nerves but can also represent inhibition
related to painful processes such as arthritis. Interpreting patient’s complaints of pain can be an arduous
process. Referred pain, which is pain perceived at a site distant from its origin, is well understood in
other compressive neuropathies, such as cervical spondylosis with radiculopathy, but underappreciated
in the upper extremity. The examiner must understand not just motor nerve and cutaneous nerve
anatomy, but also joint innervation anatomy.
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Physical Exam
Accurate testing of motor strength is significantly more complicated than one would assume. The tension
of a muscle-tendon unit is created by (1) stretch of the muscle-tendon unit and (2) active contraction of
the muscle. To assess muscle weakness related to motor nerve dysfunction, one must test the muscle in a
position that eliminates the contribution of tension from stretch. The muscle should be at its “resting
length,” on the Blix curve, where the sarcomeres are in equilibrium rather than the “position of rest”
where the resting tension of the flexors is balanced by the resting tension of the extensors. 5 This principle
is used in tendon transfers, where the wrist is placed in extension to gain finger flexion power. If the
finger flexors are weak from any cause, actively extending the wrist will increase their tension and
apparent strength, potentially masking early weakness related to nerve compression.
Sensory loss is measured subjectively or quantitatively. Semmes-Weinstein monofilaments are used for
sensory perception threshold; static and moving two-point discrimination values can be applied to assess
nerve continuity and density. Provocative maneuvers such as Tinel, Phalen, manual compression, and
scratch-collapse tests can be helpful in supporting a diagnosis if positive. 6 Abnormal deep tendon
reflexes are signs of nerve root or spinal cord compression.
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Adjunctive Studies
Electrodiagnostic studies remain the primary objective test to assess peripheral nerve dysfunction. Nerve
conduction studies quantitate nerve signal velocity, latency, and amplitude and assess myelination.
Computer-aided somatosensory measurement devices have higher sensitivity and specificity in
quantitating sensory nerve dysfunction but are not in common use. Electromyography assesses muscle
innervation integrity via the presence of fibrillations, denervation potentials, and insertional activity. The
roles of ultrasound, MRI, and MR neurograms in evaluation of peripheral nerve compression are
controversial and are areas of active research. 7,8 Radiographs are frequently used to evaluate complaints
of pain in the extremities, and MRIs can show painful conditions that are not apparent on plain
radiographs, such as ligament or cartilage tears, and ganglion cysts and other soft tissue processes.
Caution is urged when interpreting any diagnostic test: false positives and false negatives exist, and
patients can have grossly abnormal tests with no symptoms and significant symptoms with completely
normal tests.
Patients who present with abnormalities of multiple peripheral nerves should be evaluated for medical
causes of peripheral neuropathy: diabetes, vitamin deficiency, liver disease, and autoimmune disease.
Hereditary neuropathy with liability to pressure palsies, related to PMP-22 gene deletion, is an example
of a demyelinating polyneuropathy. 9 Acute causes of pain and numbness may rarely be related to other
unexpected processes, such as embolic events originating from the heart or aneurysms of the ulnar artery.
In those instances, vascular studies such as Doppler, MR angiograms, or CT angiograms may be
indicated. 10
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Surgical Principles
The technique of peripheral nerve decompression is similar at all sites. Patients may often continue taking
anticoagulants because expected blood loss is minimal. 11 This shared decision should be made between
surgeon, patient, internist, and anesthesiologist. Local anesthesia containing epinephrine is safe and can
minimize cutaneous blood loss, optimize visualization, and prolong the duration of anesthesia. 12 The use
of a tourniquet is not necessary for the majority of patients, especially if the procedure is being performed
under local anesthesia. Hemostasis with bipolar cautery creates less local tissue damage than monopolar
cautery, and its use should be considered when operating near nerves. 13 Vascular supply to the nerve
should be protected when possible, especially in patients who may already have damage to intrinsic
microvasculature. The use of a minimal touch technique with avoidance of traction will minimize scar
development. Fascial bands around the nerve are exposed and divided. Little evidence exists on
operative timing for the less common forms of nerve compression. It is reasonable to use the same
guideline used for carpal tunnel syndrome (CTS): persistence of symptoms for 9 to 12 months is a
reasonable indication for surgical intervention unless there is rapid deterioration, a diagnosis of tumor, or
penetrating trauma.
Routine postoperative splinting is not indicated, and gentle range of motion can be initiated within 1 to
3 days after surgery. Postoperative pain is managed by setting appropriate expectations preoperatively
and using rest, ice, elevation, nonsteroidal anti-inflammatory drugs (NSAIDs), and acetaminophen
postoperatively (as tolerated by the patient). The prolonged use of opioids should be minimized: up to 10
tablets is acceptable for most operations. 14 For patients on chronic opioids, consultation with their pain
physician and the anesthesiologist is recommended to create a plan for multimodal pain management.
Intraoperative ketamine is increasingly being used as an adjunct. 15
Operative risks of nerve decompression include incomplete release, damage to the nerve or surrounding
structures, hematoma, infection, devascularization of the nerve, excessive scarring, incomplete recovery,
worsened pain, and chronic regional pain syndrome. Risks related to general or sedation anesthesia can
be decreased by the use of local anesthesia alone. 16
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Median Nerve Compression
Carpal Tunnel Syndrome
Anatomy
CTS is the most commonly recognized compressive neuropathy in the upper extremity, with an incidence
of approximately 2.3 cases per 100 person-years. 17 The carpus forms a U-shaped canal, connected
anteriorly by the transverse carpal ligament (TCL). The median nerve is protected by the TCL but is
subjected to compression by any process that increases the pressure within the tunnel. The tunnel
contains nine tendons and the median nerve. The sensory part of the median nerve innervates the volar
surfaces of the thumb, index finger, long finger, and the radial half of the ring finger, but not the thenar
eminence. The recurrent motor branch of the median nerve innervates the thenar muscles and can be
subligamentous, intraligamentous, or extraligamentous.
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Etiology
Most cases of CTS are presumed to be idiopathic in origin. CTS is much more common in women than
men. Other risk factors include metabolic (obesity, diabetes, pregnancy, hypothyroidism, renal failure,
amyloidosis, autoimmune disease), infectious (leprosy), mechanical (trauma, large lumbrical muscles,
fibrosis of the tenosynovium), or a combination of factors. 18
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Diagnosis
The diagnosis of CTS is made predominantly by history and physical examination, with adjunctive
diagnostic tests when clinically indicated. 18 Early symptoms of CTS include aching pain in the carpal
tunnel area, and numbness and/or tingling in the tips of the radial digits, particularly at night or on
waking. Numbness on the dorsal hand is inconsistent with the diagnosis. Thenar muscles are examined
for strength and bulk (Figure 70.1). Atrophy is a late finding but can also be the result of disuse from
thumb carpometacarpal joint arthritis, a common condition in aging women. Provocative maneuvers
such as the Phalen test, Tinel sign, Durkan test, and scratch-collapse test are all helpful to some degree to
confirm the location of nerve compression. There is no single clinical finding that defines CTS: it involves
a constellation of signs and symptoms present over time. Electrodiagnostic studies can be helpful when
there is ambiguity or liability involved but they do not add significantly to the decision to operate. 19
Radiographs of the wrist are indicated for evaluation of wrist pain.
FIGURE 70.1 An 8-year-old patient with dense sensory deficit in median distribution and severe thenar atrophy.
For a relatively straightforward anatomic situation, CTS generates considerable controversy regarding
diagnostic criteria, the role of diagnostic testing, causality, and treatment. Whether or not CTS is “work-
related” remains debatable, 20 but clearly it is much easier to treat strictly as a medical condition rather
than a plight of employment.
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Nonoperative Treatment
Wrist splints decrease tendon excursion and hold the wrist in a position of decreased tunnel pressure.
Hand exercise (tendon excursion under load) tends to aggravate CTS, whereas stretching exercises seem
to reduce swelling, and thus pain. Antiinflammatory medications can decrease pain and tenosynovial
swelling within the carpal tunnel. Steroid injections can be considered a therapeutic test—if the
symptoms improve then recur after a steroid injection, surgery will generally provide relief. Direct
intraneural injections can cause severe, irreversible nerve damage, and ultrasound guidance can help
prevent this complication. Diuretics and oral steroids are not indicated. Vitamin supplements such as B6
can be helpful if there is a vitamin deficiency.
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Operative Treatment
Operative treatment is reasonable if symptoms progress beyond mild and intermittent despite
conservative measures. The TCL and distal antebrachial fascia of the forearm are divided via a palmar
incision. Internal neurolysis is not indicated in most cases. Revision surgery or decompression in the
setting of rheumatoid arthritis generally calls for an extended incision crossing the wrist crease (Figure
70.2).
FIGURE 70.2 Severe recurrent carpal tunnel syndrome treated with open carpal tunnel release and internal neurolysis.
The results of surgery are gratifying and consistent, regardless of technique (open versus limited open
versus endoscopic), although practitioners are often passionate about their preference. Long-term relief of
symptoms is achieved in up to 91% of cases. 21 Postoperative splinting has been found to be unnecessary.
22 Surgical complications are pillar pain (aching of the proximal palm), tendon subluxation over the hook
of the hamate, and injury to the ulnar nerve and local median nerve branches.
Recurrence of CTS is rare (it is not less than 53%), and the patient should be questioned about initial
postoperative symptom relief. 23 If there was temporary improvement followed by recurrence, scarring
should be suspected. If there was minimal to no improvement with surgery, consideration should be
given to a diagnosis of incomplete release, permanent uncorrectable intraneural damage, or other sites of
nerve compression. Revision carpal tunnel surgery can be performed endoscopically, 24 or open with or
without hypothenar fat grafting.
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Proximal Median Nerve Entrapment
Pronator syndrome or proximal median nerve entrapment (PMNE) is a subtle diagnosis, also of
substantial controversy. 25 It is described as rare in the medical literature but is becoming recognized as
being more common than previously thought. Different from CTS, in which pain is at the site of
compression, compression of the median nerve at the elbow causes pain in the hand or wrist: there is no
spontaneous pain in the region of the pronator. Pain is typically in the palm, wrist, and distal forearm and
is exacerbated by activities involving sustained forearm pronation.
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Diagnosis
The diagnosis of PMNE is determined predominantly by history and physical exam. 25 Early symptoms
include weakness of pinch, dropping things when the wrist is being held in flexion, and vague,
intermittent, aching pain in the wrist. Hand weakness involves the flexor pollicis longus (FPL) and flexor
digitorum profundus to the index finger (FDP IF). The pronator quadratus (PQ) is the third muscle
innervated by the anterior interosseous nerve (AIN), but it is difficult to isolate for strength testing.
The wrist pain is typically diagnosed as “tendonitis” but does not respond to treatment for tendonitis.
Numbness with PMNE is a relatively late symptom and typically occurs at night. PMNE is often confused
with CTS, and the diagnosis is often only considered after carpal tunnel release fails. The thenar area
tends to be involved, distinctly different from CTS. The palmar cutaneous branch of the median nerve
exits the median nerve about 5 cm proximal to the wrist and provides cutaneous innervation to the thenar
area. Thenar muscles maintain normal strength with PMNE.
Symptoms of hand numbness related to PMNE can be provoked by firm palpation of the median nerve
just proximal and distal to the elbow crease and with pronation against resistance. Numbness occurring
in less than 60 seconds is considered abnormal.
To assess the strength of the muscles innervated by the AIN, muscles must be tested at their “resting
length.” The wrist is at neutral position, and the metacarpophalangeal (MCP), proximal interphalangeal
(PIP), and distal interphalangeal (DIP) joints are flexed to 90°. The strength of the FDP IF should be
similar to that of the FDP of the middle finger. Testing pinch strength of the FPL and FDP IF with the “O”
sign is only valid if the wrist is in neutral position and not extended. 5 The FPL is tested with the wrist
neutral and the thumb metacarpal in abduction. Weakness of FDP IF and FPL resolves immediately in the
recovery room following surgical release.
Patients with preexisting subclinical PMNE are at increased risk for development of AIN palsy with
trauma to the forearm, or pressure in the area related to prolonged elbow flexion (as with sling
immobilization after shoulder surgery). 26
Electrodiagnostic studies are not helpful in the diagnosis of PMNE but can exclude other causes of nerve
dysfunction. The electromyography should include muscles distal to the area of compression, specifically
the FPL, FDP IF, and PQ. The role of ultrasound, MRI, and MR neurograms is not defined.
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Nonoperative Treatment
Nonoperative treatment includes avoidance of sustained and/or prolonged pronation and correction of
postural issues that magnify other nerve disorders such as thoracic outlet syndrome and cervical
spondylosis. Ergonomic modifications such as split keyboards, vertical computer mice, voice-activated
software, sit-stand desks, driving with hands on the bottom half of the steering wheel, and modified
touring bicycle handlebars may help to reduce symptoms.
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Operative Treatment
Operative treatment is an option if the diagnosis is clear by history and examination, if the patient’s
symptoms are not mild and intermittent, and if they persist or progress in spite of modification of
activities. Surgical decompression should address all areas of possible compression of the median nerve
around the elbow. From proximal to distal, this includes the fascia of Struthers, the ligament of Struthers
(if present), the deep fascia of the proximal pronator teres muscle, the bicipital aponeurosis, the deep
fascia of the ulnar origin of the pronator teres muscle, the deep fascia of the humeral origin of the
pronator teres muscle, and the fascia of the arch of the superficial flexors. Large incisions are not
necessary (Figure 70.3), and there is no indication for postoperative splinting, immobilization, or physical
therapy. If wrist pain is the main indication for surgery, release of the bicipital aponeurosis under local
anesthesia can be highly effective with a quick recovery. 25
FIGURE 70.3 Typical incisions for decompression of the proximal median nerve.
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Anterior Interosseous Nerve Syndrome
The AIN is the most proximal branch of the median nerve in the forearm. There are multiple reported
cases of spontaneous AIN palsy, expressed as an acute loss of active flexion of the FPL and the FDP IF
and paralysis of the PQ. 27 The cause remains unknown, and treatment is predominantly nonoperative.
Weakness is generally self-limited and will often spontaneously resolve. The differential diagnosis
includes Parsonage-Turner Syndrome and Kiloh-Nevin Syndrome. Parsonage-Turner is a form of
neuralgic amyotrophy thought to be related to the anterior horn cell and preceded by a viral illness. It
generally resolves spontaneously. 28 Kiloh-Nevin Syndrome is thought to be focal viral or inflammatory
neuritis of the AIN that presents clinically as AIN palsy and that is also expected to recover
spontaneously. 29 At least one report, however, demonstrated three cases of prompt return of motor
strength following AIN decompression. 30 In one patient, the intraoperative amplitude of the AIN
immediately increased from 40 mv to 200 mv after release of the fascia over the AIN.
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Ulnar Nerve Compression
Cubital Tunnel Syndrome
Etiology
Cubital tunnel syndrome is the second most commonly recognized compressive neuropathy in the upper
extremity with an incidence of 21 events in 100,000 person-years. 1 It is caused by compression of the
ulnar nerve by structures around the elbow. The most common sites of compression are the Arcade of
Struthers and intermuscular septum proximal to the elbow, Osborne ligament at the medial epicondyle,
and the pronator muscle and flexor fascia distal to the elbow. Other sources of compression are anatomic
variations such as the epitrochlearis anconeus muscle, bone spurs, or soft tissue masses in or around the
nerve. Risk factors for cubital tunnel syndrome include male gender, performance of heavy manual labor,
and tobacco use. 1
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Diagnosis
The diagnosis of cubital tunnel syndrome is made largely by history and physical exam. Early symptoms
of cubital tunnel compression include numbness and tingling along the ulnar aspect of the hand, often
with proximal radiation of pain along the path of the nerve. Altered sensation of both the dorsal and
volar aspects of the ulnar hand distinguishes compression at the level of the elbow from compression at
the wrist that causes numbness on the volar surface of the hand. Prolonged compression may lead to
complete loss of sensation of the small and ulnar half of the ring fingers and ulnar border of the hand.
Ulnar clawing (hyperextension of the MCP with flexion of the PIP and DIP joints), flattening of the
palmar arches, and hypothenar atrophy are late findings. Abnormal motor findings include weakness of
ulnar-innervated muscles, a positive Froment sign, and loss of ability to concomitantly flex the MCP
joints and extend the PIP and DIP joints (the ulnar negative posture). It is important to examine the nerve
at both the elbow and hand to determine the level of compression, remembering that compression may be
present at both sites. Pain is a variable finding, and patients may use a variety of words to describe the
sensations associated with nerve compression. 31
Intrinsic muscle atrophy combined with sensory loss without a peripheral explanation suggests an
unusual underlying neurologic disorder such as Charcot-Marie-Tooth, or syringomyelia. Loss of muscle
strength with a normal sensory exam is an early sign of amyotrophic lateral sclerosis. 32
X-rays of the elbow may be performed if there is a history of trauma or if heterotopic ossification or
arthritis is suspected. Electrodiagnostic tests, ultrasound, and MRI have all been used to isolate the level
of compression and look for other pathology. 7,8
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Treatment
Nonoperative management with night splinting, physical therapy, and activity and postural modification
is indicated for mild disease and has a 50% rate of efficacy. 33 Operative management is indicated when
symptoms and signs persist or worsen despite conservative management. Accepted procedures include
simple decompression via open or endoscopic approaches, anterior (subcutaneous) transposition, and
intra- or submuscular transposition. Although some have advocated a tailored surgical approach, using
simple decompression for mild disease and submuscular transposition for severe or recurrent disease,
more recent studies suggest that all procedures have high rates of success. 34 The management of the
subluxating nerve is still under debate with some surgeons transposing the nerve only if subluxation is
noted pre- or intraoperatively. Positive functional and sensory outcomes of cubital tunnel release are
high, and have been measured at 77% to 86% at 1 year after surgery. 35,36
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Ulnar Tunnel Syndrome
Anatomy
The ulnar tunnel, also known as Guyon canal, is the site of ulnar nerve compression at the wrist. Distal to
the take-off of the dorsal ulnar cutaneous nerve, the ulnar nerve passes between the hamate and pisiform
dorsal to the palmar carpal ligament, the palmaris brevis, and fatty tissue and volar to the carpus. It
travels ulnar to the ulnar artery and, within the canal, branches into a deep motor branch and a more
volar sensory branch. The nerve can be compressed proximal to or within the canal and can involve the
motor and/or the sensory branch.
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Etiology
Causes of ulnar nerve compression within Guyon canal are more varied than compression at the cubital
tunnel and include local fascial bands, ganglion cysts, soft tissue masses, fracture callus, vascular
anomalies, aberrant muscles, and tophaceous gout. It is not uncommon to see simultaneous presentation
of symptoms of median nerve and ulnar nerve compression at the wrist, and studies have shown
improvement in ulnar nerve symptoms after median nerve decompression alone. 37,38
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Diagnosis
Symptoms are similar to those seen in cubital tunnel syndrome but are limited to the hand. A thorough
examination of the neck, arm, and hand should be performed to exclude proximal disease. Exams should
include palpation, assessment of vascular supply, provocative maneuvers including Tinel, Phalen, and
scratch-collapse tests, and evaluation of grip and pinch, and sensory exams. X-ray exams can look for
hamate fractures or other bone pathology around the ulnar wrist. Electrodiagnostic tests can assess for
muscle involvement. MRI or ultrasound may be useful in looking for anatomic variations and masses
within Guyon canal.
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Treatment
Splinting and activity modification can be used for mild and intermittent symptoms. If these fail, surgical
decompression of the tunnel is reasonable. The incision extends from approximately 4 cm proximal to the
wrist crease over the flexor carpi ulnaris (FCU) tendon onto the hypothenar eminence. The FCU is
retracted ulnarward, and the nerve is gently dissected free from the ulnar artery and overlying fascia. It is
important to identify and release both the motor and sensory branches in the canal as well as the
antebrachial fascia in the forearm. The pisohamate ligament should be identified and divided, protecting
the nerve at the distal tunnel. Care should be taken to avoid damage to the ulnar artery. Vascular supply
to the hypothenar muscles should be preserved if feasible.
The outcomes of ulnar tunnel release have not been examined in the English language literature to the
extent of those for cubital tunnel syndrome. Kaiser et al found a 90% rate of subjective and
electrodiagnostic improvement in a group of 13 patients. 39
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Radial Nerve Compression
The radial nerve is responsible for extension of the fingers and wrist, and sensation on the dorsal radial
hand and radial wrist. Radial nerve entrapment with palsy is relatively rare and presents as loss of finger
extension and, if the site of neuropathy is proximal to the posterior interosseous nerve (PIN), loss of wrist
extension. The most vulnerable area of the radial nerve is in the spiral groove along the lateral aspect of
the distal humerus. “Saturday Night Palsy” refers to temporary paralysis of the motor aspect of the radial
nerve from sustained local pressure on this aspect of the upper arm while sleeping or unconscious due to
intoxication and generally resolves completely. Radial nerve entrapment at the lateral intermuscular
septum causes aching pain distally in the radial tunnel area. Radial nerve palsies associated with distal
humerus fractures represent a common therapeutic dilemma as to whether or not the nerve should be
explored surgically. 40 If the palsy is from a stretch injury, spontaneous recovery can generally be
expected. If the nerve is transected, it should be repaired primarily.
Radial tunnel syndrome (RTS), defined as pain without weakness in the dorsal forearm and wrist
provoked by resisted supination, extension of the wrist, or isolated middle finger extension is somewhat
controversial. RTS has up to a 41% overlap with lateral epicondylitis, contributing to the debate. 41,42
Electrodiagnostic studies are not helpful for evaluating either condition.
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Nonoperative Treatment
Symptoms sometimes resolve spontaneously. Physical therapy can be helpful, particularly with massage
and eccentric strengthening. Steroid injections and antiinflammatory medication can give relief, and if so,
would imply an inflammatory or edema-related condition. Approximately 25% of patients were observed
to improve with conservative care. 41
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Operative Treatment
The approach to the radial tunnel can be anterior, posterior, or between the extensor digitorum
communis and the extensor carpi radialis brevis. Dissection using a posterior approach can be tedious
because of arborization of the motor nerves to the finger extensors. The anterior approach avoids
intramuscular dissection but requires attention to cutaneous nerves and numerous enveloping vessels.
Muscular dissection through the extensor carpi radialis brevis may result in a wide scar (Figure 70.4). The
fascia of the supinator is released over the PIN (the arcade of Frohse), and a transverse tenotomy of the
common extensor fascia is performed.
FIGURE 70.4 Widened radial tunnel incision.
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