Operative Technique in Plastic Surgery – Kevin C.Chung

■ Although evidence for steroid injections is limited to a single small trial, it
may be considered for patients with ongoing symptoms who are poor surgical
candidates or those who do not want to consider surgery.17
■ When a local anesthetic is mixed with the steroid injection, this can serve as a
diagnostic aid and is considered successful if both pain symptoms are
temporarily alleviated and a motor block of the PIN is achieved.
SURGICAL MANAGEMENT
■ Operative radial nerve decompression is indicated for those patients who have
failed to improve after prolonged nonoperative treatment.
■ Intravenous regional (Bier block) and axillary block regional are preferred
methods of anesthesia.
■ Three commonly described dorsal surgical approaches to release potential
compression points along the radial tunnel have been described.
■ ECRB-extensor digitorum communis (EDC) interval
■ ECRL-BR interval
■ BR transmuscular splitting approach
■ The authors prefer the ECRL-BR interval for the following reasons:
■ It avoids muscle splitting.
■ It allows for easy identification of the radial nerve, PIN, and the sensory
branch of the radial nerve to ensure all are free from compression.
• There is some evidence to support more reliably successful outcomes with
decompression of the SBRN, which is best addressed through this
interval.18–20
• The most common complication of radial tunnel decompression is
neuropraxia of the SBRN, which is best identified and protected in this
interval.20–23
■ The interval is easily identifiable when marked out in the preoperative area
by having the patient flex the elbow against resistance.
T E C H N I Q U E S
■ Radial Tunnel Decompression
Exposure

■ In the preoperative area, ask the patient to flex the elbow against resistance
to help mark out the interval between BR and ECRL.
■ This causes brachioradialis (BR) to become prominent while the extensor
carpi radialis longus (ECRL) is relaxed, making the interval much easier to
locate.
■ A straight longitudinal or lazy-S incision is made through the skin and
dermis (TECH FIG 1A).
■ Care is taken to identify and protect the posterior cutaneous nerve of the
forearm and any posterior branches of the lateral antebrachial cutaneous
nerve.
■ The fascia overlying BR and ECRL is incised and the interval is developed
(TECH FIG 1B).
■ BR fascia is thinner, and thus, the BR muscle belly will appear as a
brighter red color.
■ The dorsal ulnar edge of BR is also thinner, coming to a tapered edge and
lying superficial to the more dorsal central aspect of the ECRL.
■ This interval should open easily and with mostly blunt dissection. If
extensive sharp dissection is required, the surgeon has likely strayed out of
the appropriate interval.
Release of Entrapment
■ Coming down between BR and ECRL will bring the surgeon to a layer of fat
containing the SBRN.
TECH FIG 1 • A. Proposed incision over the dorsal
proximal forearm marked out at interval between
brachioradialis and extensor carpi radialis longus. B.
Superficial interval between brachioradialis (BR) and
extensor carpi radialis longus (ECRL). Note the

thinner edge of BR and the more rounded, dorsal
central aspect of ECRL.
TECH FIG 2 • A. Intermediate interval between
extensor carpi radialis longus (ECRL) and extensor
carpi radialis brevis (ECRB) ulnarly and
brachioradialis (BR) radially. The radial recurrent
vessels (leash of Henry) course through and over the
radial nerve branches (PIN, SBRN, nerve to ECRB).
B. Deep interval after limited external neurolysis of
radial nerve branches, ligation of crossing vessels,
and release of proximal edge ECRB reveals the tight,
tendinous leading edge of supinator (arcade of
Frohse) directly compressing the PIN. C. Release of

the supinator reveals a chronic compression deformity
of the PIN. (For all parts, proximal is to the left, distal
to the right, radial to the top, and ulnar to the bottom.)
■ Follow the SBRN proximal, and you will encounter the radial recurrent
vessels (leash of Henry) (TECH FIG 2A).
■ They must be ligated with suture or clips.
■ Dissecting more proximally within this interval, follow the SBRN and you
will encounter the posterior interosseous nerve (PIN) and the nerve to
extensor carpi radialis brevis (ECRB).
■ Meticulous care to dissect and control crossing vessels is essential.
■ Release any constricting fascial bands over the SBRN as this may increase
the likelihood of success.18–20
■ At this point, you will have identified the SBRN, nerve to ECRB, and the
PIN (TECH FIG 2B).
■ From radial to ulnar, the orientation will be SBRN, nerve to ECRB, and
PIN.
■ The PIN will be larger in caliber and coursing distal and ulnar.
■ The SBRN and nerve to ECRB will be parallel to one another.
■ Follow the PIN distally and release the overlying ECRB fascia, which can be
a point of compression.
■ After ECRB fascia has been released, you will encounter the supinator fascia
(arcade of Frohse), which must be released (TECH FIG 2C).
■ As ECRB has been implicated in lateral epicondylar tendinopathy, release
of the ECRB tendon may be helpful for patients with concomitant “tennis
elbow.”
■ Check proximally and distally to ensure no further entrapment points exist.
■ Proximally, fibrous bands over the radial head can sometimes be found.
■ If used, the tourniquet is released to ensure adequate hemostasis.
■ Close the skin using a dermal layer with 4-0 absorbable suture followed by a
subcuticular layer using 4-0 absorbable suture.
■ A long-arm, soft bulky dressing is applied using a thin layer of gauze, sterile
cast padding, and a very lightly compressive wrap.

PEARLS AND PITFALLS
Preoperative
marking
■ Marking out the BR-ECRL interval in the preoperative holding
area with the patient flexing the elbow against resistance can
make surgical orientation much easier.
Hemostasis
■ Meticulous care to control crossing vessels throughout the case
is a part of the decompression, can save time when the
tourniquet is let down, and will prevent postoperative hematoma
formation.
Adequate
exposure
■ A minimal exposure can lead to inadequate visualization of all
compression points and necessitate excessive retraction on the
muscular interval, as well as the SBRN, leading to known
complications.
Decompression
of all radial
nerve branches
■ External neurolysis of the radial nerve, nerve to ECRB, PIN,
and SBRN is important to maximize likelihood of success.
POSTOPERATIVE CARE
■ Immediate active digital, wrist, and forearm motion is allowed, but with
limited weight bearing until the 2-week clinic follow-up.
■ The dressing is removed 2 days after surgery.
■ The wound is checked and any external sutures are removed at 2 weeks.
■ Strengthening allowed at 3 weeks and patients are expected to be back to
normal work activities by weeks 4 to 6.
OUTCOMES
■ No level 1 evidence exists to guide expected outcomes following radial tunnel
release.
■ Patients who have had “successful” outcomes following radial tunnel release
varies widely in the literature from 32% to 97%19,21,22 prompting controversy
as to the effectiveness of the procedure.
■ Known risk factors that lower expected success rates of radial tunnel
decompression include
■ Concomitant lateral epicondylitis22
■ Multiple entrapment neuropathies22
■ Workers compensation/litigation22

■ A recent study by Lee and colleagues found good results in 86% of patients
with isolated RTS, whereas this number dropped to 57% in patients with
multiple entrapment neuropathies and 40% in patients with associated lateral
epicondylar tendinopathy.22
■ A thorough examination of available literature makes it clear that appropriate
patient selection based on clinical history, exam, and diagnostic workup is
crucial to success in the treatment of RTS.
COMPLICATIONS
■ Complication rates have been reported in a portion of available retrospective
reviews and case series; however, the anticipated rate of these complications is
difficult to determine.
■ Some reported complications include
■ SBRN neurapraxia or hyperaesthesias20–22
■ Paresis of common digital extensors21,23
■ Postoperative hematoma21
■ Complex regional pain syndrome20
■ Infection20
REFERENCES
1. Dang AC, Rodner CM. Unusual compression neuropathies of the forearm,
part I: radial nerve. J Hand Surg Am. 2009;34(10):1906-1914.
2. Eaton CJ, Lister GD. Radial nerve compression. Hand Clin. 1992;8(2):345-
357.
3. Rosenbaum R. Disputed radial tunnel syndrome. Muscle Nerve.
1999;22(7):960-967.
4. Konjengbam M, Elangbam J. Radial nerve in the radial tunnel: anatomic sites
of entrapment neuropathy. Clin Anat. 2004;17(1):21-25.
5. Portilla Molina AE, Bour C, Oberlin C, et al. The posterior interosseous nerve
and the radial tunnel syndrome: an anatomical study. Int Orthop.
1998;22(2):102-106.
6. Riffaud L, Morandi X, Godey B et al. Anatomic bases for the compression
and neurolysis of the deep branch of the radial nerve in the radial tunnel. Surg
Radiol Anat. 1999;21(4):229-233.
7. Lin YT, Berger RA, Berger EJ et al. Nerve endings of the wrist joint: a
preliminary report of the dorsal radiocarpal ligament. J Orthop Res.
2006;24(6):1225-1230.

8. Roquelaure Y, Raimbeau G, Saint-Cast Y, et al. [Occupational risk factors for
radial tunnel syndrome in factory workers]. Chir Main. 2003;22(6):293-298.
9. van Rijn RM, Huisstede BM, Koes BW, et al. Associations between work-
related factors and specific disorders at the elbow: a systematic literature
review. Rheumatology (Oxford). 2009;48(5):528-536.
10. Lister GD, Belsole RB, Kleinert HE. The radial tunnel syndrome. J Hand
Surg [Am]. 1979;4(1):52-59.
11. Moradi A, Ebrahimzadeh MH, Jupiter JB. Radial tunnel syndrome, diagnostic
and treatment dilemma. Arch Bone Jt Surg. 2015; 3(3):156-162.
12. Loh YC, Lam WL, Stanley JK, et al. A new clinical test for radial tunnel
syndrome—the rule-of-nine test: a cadaveric study. J Orthop Surg (Hong
Kong). 2004;12(1):83-86.
13. Kupfer DM, Bronson J, Lee GW, et al. Differential latency testing: a more
sensitive test for radial tunnel syndrome. J Hand Surg [Am]. 1998;23(5):859-
864.
14. Seror P. Posterior interosseous nerve conduction: a new method of evaluation.
Am J Phys Med Rehabil. 1996;75(1):35-39.
15. Ferdinand BD, Rosenberg ZS, Schweitzer ME, et al. MR imaging features of
radial tunnel syndrome: initial experience. Radiology. 2006;240(1):161-168.
16. Cleary CK. Management of radial tunnel syndrome: a therapist’s clinical
perspective. J Hand Ther. 2006;19(2):186-191.
17. Sarhadi NS, Korday SN, Bainbridge LC. Radial tunnel syndrome: diagnosis
and management. J Hand Surg Br. 1998;23(5):617-619.
18. Bolster MA, Bakker XR. Radial tunnel syndrome: emphasis on the
superficial branch of the radial nerve. J Hand Surg Eur Vol. 2009;34(3):343-
347.
19. Jebson PJ, Engber WD. Radial tunnel syndrome: long-term results of surgical
decompression. J Hand Surg [Am]. 1997;22(5):889-896.
20. Lawrence T, Mobbs P, Fortems Y et al. Radial tunnel syndrome: a
retrospective review of 30 decompressions of the radial nerve. J Hand Surg Br.
1995;20(4):454-459.
21. Atroshi I, Johnsson R, Ornstein E. Radial tunnel release: unpredictable
outcome in 37 consecutive cases with a 1-5 year follow-up. Acta Orthop
Scand. 1995;66(3):255-257.
22. Lee JT, Azari K, Jones NF. Long term results of radial tunnel release—the
effect of co-existing tennis elbow, multiple compression syndromes and
workers’ compensation. J Plast Reconstr Aesthet Surg. 2008;61(9):1095-1099.

23. Simon Perez C, Garcia Medrano B, Rodriguez Mateos JI, et al. Radial tunnel
syndrome: results of surgical decompression by a postero-lateral approach. Int
Orthop. 2014;38(10):2129-2135.

30
CHAPTER
Primary Nerve Repair and
Nerve Graft for Traumatic
Nerve Injuries
Sonya Paisley Agnew and Jason H. Ko
DEFINITION
■ In the setting of acute nerve injuries, the surgeon should abide by the
following principles when performing a nerve repair or reconstruction:
■ Debridement of the injured nerve ends to healthy fascicles
■ Correct alignment of fascicles when possible
■ Delicate handling of neural tissue
■ Tension-free repair or reconstruction
■ Prevention of fascicular outgrowth at the coaptation site
■ The level of injury, zone of injury, primary nerve function (motor vs sensory),
and functional significance of the injured nerve (eg, “critical” nerves such as
the ulnar digital nerve to the thumb vs “noncritical” nerves such as the ulnar
digital nerve to the long finger) will guide choice of treatment.
■ Options for repair include primary repair with or without a conduit vs
reconstruction with nerve grafts (autograft vs allograft).1 Consideration should
be given to techniques for bolstering the nerve coaptations (eg, fibrin glue,
nerve wraps, nerve tubes).
■ The most commonly used techniques for nerve coaptation are an “epineurial
repair,” which is suturing of the epineurium with no direct manipulation of the
fascicles, and a “grouped fascicular repair,” which requires reorienting the
fascicles and directly placing sutures into the perineurium of the fascicles (FIG
1).
■ No studies have documented superiority of one coaptation technique over the
other.

ANATOMY
■ An understanding of fascicular anatomy of mixed major peripheral nerves can
improve the outcomes of nerve repair by aligning proximal fascicles with their
distal targets—matching proximal motor fascicles to distal motor fascicles and
proximal sensory fascicles to distal sensory fascicles, whenever possible.
■ This topographical orientation has been described for major mixed nerves,
including the median and ulnar nerves, which can help with fascicular
alignment when treating lacerations at various levels in the forearm and hand.2
■ Anatomic fascicular orientations that have been well-established in the
literature1:
■ Median nerve in the forearm (FIG 2)
• The motor branches lie peripherally (in the radial and ulnar aspects of the
median nerve), with sensory fascicles located centrally. The recurrent motor
fascicle is a separate, distinct fascicle 10 cm proximal to the radial styloid
and located radially.
■ Median nerve at the wrist level (see FIG 2)
• Recurrent motor fascicles are located within the volar and radial aspect of
the nerve.
• Digital sensory fascicles are located dorsally along both the radial and ulnar
aspects of the nerve.
■ The ulnar nerve in the forearm (see FIG 2)

FIG 1 • Nerve coaptation techniques. A. Epineurial
repair. B. Grouped fascicular repair.

FIG 2 • Intraneural topography of the median nerves at
various levels.
• Dorsal sensory branch of the ulnar nerve is located in an ulnar position
within the nerve and separates from the main nerve 5 to 8 cm proximal to
the radial styloid.
• The intrinsic motor fascicles lie dorsal to the digital sensory fascicles and
are distinct 9 cm proximal to the ulnar styloid.
• In the proximal forearm, the motor fascicles (intrinsic and flexor carpi
ulnaris [FCU]/flexor digitorum profundus [FDP]) are centrally located, and
the sensory fascicles are superficial.
• At the wrist level, the ulnar nerve motor branch is dorsal and ulnar relative
to the sensory fascicles—the motor fascicles can be seen as separate and
distinct up to 9 cm proximal to the ulnar styloid.3
■ Grouped fascicular repair should be used in larger mixed nerves, such as the
median nerve at the humeral level.3
■ Care should be taken to avoid bulky perineurial sutures that may become an
obstacle to axonal regrowth.

■ The less the ends of the nerve are manipulated intraoperatively, the less
scarring there will be at the coaptation site.
■ Microsutures should be used to repair the epineurium for all nerve repairs. The
coaptation sites can be augmented with fibrin glue at the discretion of the
surgeon.
■ Tension should be avoided at all cost when performing a nerve coaptation. In
the authors’ opinion, rather than repairing a nerve under tension, the surgeon
should reconstruct the nerve with an interpositional nerve graft (autograft or
allograft) to achieve a tension-free construct.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Physical exam:
■ A thorough motor examination and evaluation of sensation by two-point
discrimination or Semmes-Weinstein monofilament testing will help to
localize the nerve injury and adequately counsel the patient regarding
postoperative expectations.
■ The location of a Tinel sign will help to pinpoint the site of nerve injury in
the acute setting, and an advancing Tinel sign can be used to measure nerve
regeneration over time.
■ In the acute setting, the sensory examination may be unreliable due to pain or
neurapraxia.
■ History: When obtaining the patient’s history, certain factors are important for
preoperative planning and counseling, including the following:
■ Patient age: Nerve regeneration occurs more rapidly in younger patients. The
potential for nerve recovery decreases with age and should be addressed
preoperatively with the patient. Older individuals are more likely to have
delayed and/or incomplete recovery.
■ Chronicity of injury: In a delayed nerve repair, the surgeon should be
prepared for retraction of the proximal nerve stump, in addition to neuroma
formation, which may necessitate the use of nerve grafts.
IMAGING
■ Ultrasound may be helpful in determining the presence of neuroma-in-
continuity or complete laceration of the nerve. It offers the advantage of
allowing static and dynamic assessments of the nerve and associated structures.
■ MR neurography can also be used to evaluate larger nerves, but it is less
effective at visualizing smaller nerves in the palm and fingers.

■ Other imaging modalities are not commonly used for traumatic nerve injuries.
Operative exploration is the primary method of diagnosis and treatment.
SURGICAL MANAGEMENT
Preoperative Planning
■ The patients should be monitored closely to determine the extent of peripheral
nerve injury.
■ A penetrating injury with acute nerve deficit warrants operative exploration.
■ A blunt or closed injury with acute nerve deficit may justify a period of
monitoring to rule out neurapraxic injury.
■ Sharp injury: If addressed acutely, primary nerve repair is possible. Nerve
wraps or conduits can be used as adjuncts, if there is minimal tension at the
repair site. If primary repair is under tension, then interpositional nerve graft
should be used for reconstruction instead.
■ Crush injury: The surgeon should be prepared for a broad zone of injury with
extensive injury to the nerve. Nerve grafting will most likely be necessary, and
the surgeon should consider delayed repair so that the zone of injury in the
nerve can be better assessed as the soft tissue heals.
■ Poor soft tissue cover: It is important for the surgeon to perform local or
distant soft tissue flaps to achieve a stable, well-vascularized soft tissue
envelope over the site of a nerve injury. Stable overlying soft tissue is a
prerequisite for successful nerve repair or reconstruction.
■ Timing: Neuromuscular function disappears 3 to 5 days after nerve
transection,4 whereas nerve action potentials remain for 7 to 9 days after
injury.5 After this time period, the use of intraoperative stimulation to aid in
fascicular identification is not possible.
Positioning
■ Supine positioning
■ For distal nerve injuries in the upper extremity, a well-padded tourniquet is
placed on the proximal arm.
■ The authors recommend tourniquet use to maintain a bloodless field, which
will more easily identify peripheral nerves, especially in the setting of
substantial scarring.
■ However, if intraoperative motor nerve stimulation will be performed, the
tourniquet should be released within 30 to 40 minutes to avoid tourniquet

neurapraxia.
■ The hand table should have a stable base to limit motion during microsurgery.
■ If sural nerve grafts are indicated, one or both legs are circumferentially
prepared, and a thigh tourniquet should be used. It may be beneficial to harvest
the sural nerve from the contralateral leg, which allows a bump to be placed
under the contralateral hip.
Approach
■ Bruner incisions to cross wrist and digital creases are employed to avoid
straight-line incisions across joints.
■ For sural nerve harvest, stair-step incisions may be used to decrease the overall
length of the harvest site (FIG 3). However, longitudinal incisions directly over
the entire length of sural nerve can be performed. Endoscopic sural nerve
harvest techniques can also be employed.
■ Nerve repair and reconstruction requires identification of injured nerve ends.
Bruner or mid-lateral incisions should be used to expose the injured nerve(s)
on the volar aspect of the palm or fingers. Bruner extensions should be used
across all volar joint creases in the upper extremity. Dorsally, longitudinal
incisions can be made over joint surfaces.
■ Tenotomy scissors should be used to dissect the proximal and distal ends of
the injured nerve(s) as atraumatically as possible. Overlying fascia or
compression points should be released for better mobilization of the nerve
ends.
FIG 3 • A,B. Stair-step sural nerve harvest.
T E C H N I Q U E S

■ Primary Nerve Repair
■ A direct repair is indicated in a sharp laceration when the nerve ends may be
brought together with no tension.
■ Traumatized fascicles should be sharply debrided to healthy-appearing
ends and oriented (in cases of larger nerves) appropriately.
■ If the nerve ends cannot be approximated without any tension, direct nerve
repair should not be performed—nerve grafting should be used instead.
■ If nearby joints (eg, fingers, wrist, elbow) have to be flexed down to help
minimize tension on the nerve repair, the primary nerve repair is too tight
and should be abandoned.
■ Lining up epineurial vessels proximally and distally can be used to help with
orientation at the time of nerve repair. This will make pairing up the proximal
and distal fascicles easier.
■ Use of an operating microscope is recommended,6 and 8-0 or 9-0
nonabsorbable monofilament suture should be used for epineurial repair to
orient proximal fascicles to their distal targets (TECH FIG 1A–F)
■ Fascicles that are “outpouching” should be tucked into the epineurial repair
and trimmed back if necessary (TECH FIG 1G,H).
■ A piece of surgical glove, Esmarch bandage, or silicone background can be
used like a “burrito” to wrap around the repair into which fibrin glue is
applied to bolster the repair. After the fibrin glue has set, the burrito wrap is
removed.
■ At this point, the surgeon should consider releasing any potential distal
compression points (eg, the transverse carpal ligament distal to a median
nerve repair in the distal forearm; Guyon canal release after an ulnar nerve
repair at the wrist).

TECH FIG 1 • Ulnar nerve repair proximal to the
elbow. Anterior transposition can be performed to
reduce tension on the nerve coaptation. A. Gunshot
wound with suspected ulnar nerve injury. Dotted
marks outline possible incision location. B. Exploration

reveals a complete ulnar nerve transection proximal to
the elbow. C. Anterior transposition of the ulnar nerve
has been performed by extending the skin incision
distally and completely releasing the ulnar nerve from
the cubital tunnel. D. Anterior transposition of the ulnar
nerve allows for tension-free primary nerve coaptation.
E. Fascial sling of the flexor-pronator wad elevated
sharply anterior to the medial epicondyle. F. The
fascial sling is sutured to the deep surface of the
anterior skin flap. G. Outpouching of the fascicles
should be avoided to prevent aberrant axonal
regeneration. H. The fascicles should be trimmed and
aligned to maximize regeneration.
■ Repair in the Setting of a Small Nerve Gap in a
Small Caliber Nerve
■ When the ends of a nerve cannot be brought together without tension despite
proximal and distal mobilization, use of a nerve graft is indicated.
■ For digital nerve gaps, lateral antebrachial cutaneous (LABC) nerve, medial
antebrachial cutaneous (MABC) nerve, and posterior interosseous nerve
(PIN) are suitable sizes for autograft (TECH FIG 2). These have the
additional benefit of using a donor site in the same surgical area as the nerve
reconstruction.
■ Alternatively, processed nerve allograft (PNA) of varying lengths and
diameters are available as an off-the-shelf option with no donor site concerns
(TECH FIG 3).
■ The proximal and distal ends of both repair sites can be bolstered with
absorbable polyglycolic nerve tubes, fibrin glue, or xenogenic wraps (TECH
FIG 4).

TECH FIG 2 • Posterior interosseous nerve harvest in
the dorsal wrist. A. Incision site. B. Isolation of nerve.
TECH FIG 3 • A. A 5-cm nerve gap in the median
nerve at the level of the carpal tunnel. B. Repair with
processed nerve allograft.

TECH FIG 4 • Direct digital nerve repair (A) and after
wrapping with xenogenic nerve wrap (B).
■ Repair of Larger Nerve Gaps or Larger Caliber
Nerves
■ When a large gap in a nerve exists, either cable grafts or processed nerve
allografts are indicated.
Sural Nerve Harvest Technique
■ The sural nerve can be harvested in the supine position with a well-padded
sterile tourniquet on thigh and the knee flexed.
■ A sterile sandbag and/or an assistant can keep the knee flexed and hip
internally rotated.
■ If a single sural nerve is to be used, harvesting the contralateral sural nerve
will allow a bump or pillows to be placed under the contralateral hip to help
gain better access to the posterolateral aspect of the leg, especially more
proximally where the sural nerve is deeper.
■ If bilateral sural nerves must be harvested, the surgeon should consider
performing the sural nerve harvest in the prone position, which would most
likely require an intraoperative position change to access the upper extremity.
■ Surface landmarks for sural nerve harvest—the lateral malleolus and anterior
edge of the Achilles tendon—are marked.

■ FIG 3 depicts the step-cut technique for sural nerve harvesting.
■ The sural nerve is easily located 2 cm superior and posterior to the lateral
malleolus. Distal to the malleolus, the nerve begins to branch and becomes
significantly smaller.
■ The lesser saphenous vein is intimately associated with the nerve and can
be protected or ligated.
■ Gentle traction is placed on the nerve to determine the more proximal
incisions.
■ The intervening skin bridges should be short enough that undue traction is
not necessary to free the nerve from the surrounding soft tissue.
■ The dissection proceeds proximally to the junction of the medial and lateral
sural nerves in the mid-leg, where the medial branch pierces the
gastrocnemius fascia, and the lateral sural nerve continues superficially.
■ The dissection can continue easily toward the origin of the lateral sural
nerve from the common peroneal nerve or the medial sural nerve in
between the two heads of the gastrocnemius muscle.7
■ Approximately 30 cm of sural nerve can be harvested from one leg.
■ A suture or surgical marking pen can be used to signify the proximal end so
that the graft is reversed when brought to the recipient site.
■ Graft reversal prevents theoretical loss of axonal regeneration down small
side branches and into surrounding soft tissues.
Graft Preparation
■ For large defects, multiple sural cables should be prepared, and the number
used depends on the number of large groups of fascicles within the injured
nerve, in addition to the total length of sural nerve harvested.
■ The nearby joints (fingers, wrist, elbow) should be maximally extended
when measuring the nerve graft and length of nerve graft needed.
■ This will allow the nerve graft to be placed under no tension, even with
early postoperative motion.
■ After the length of the nerve defect is measured, the number of cables
required is determined by the number of larger groups of fascicles visible that
can be matched to accept individual grafts.
■ The cables are brought together on a separate operating room table and
rolled into a “burrito” as referenced earlier, followed by augmentation with
fibrin glue.
■ This technique has been referred to as the “super nerve” technique (TECH

FIG 5A,B).
■ The ends are sharply transected, exposing the grouped fascicles, and one end
is coapted to the proximal recipient nerve defect with 8-0 or 9-0
nonabsorbable monofilament suture with the aid of an operating microscope.
■ Identical preparation is done for the distal end of the cable graft, and the
graft is inset in a similar fashion to the distal recipient nerve (TECH FIG
5C,D).
■ The central portion of the cable graft is gently draped into the soft tissues
with space between the cables to allow for revascularization.
■ The upper extremity is taken through a full range of motion to verify that the
nerve reconstruction is under no tension.
TECH FIG 5 • A,B. Preparation of multiple sural nerve
cable grafts on the back table prior to reconstruction—
the “super nerve” technique. C,D. Ulnar and median
nerves grafted with sural nerve cable grafts.
PEARLS AND PITFALLS

Nerve gap
■ Avoid tension and have low threshold to perform nerve grafting.
Fascicular
orientation
■ When possible, align fascicles at the time of repair.
Positioning
■ Repair and grafts should be tensioned to allow for “safe” positioning
of the fingers/wrist/digits. Flexed postures to accommodate primary
repair should be avoided at all costs. When in doubt, use a graft.
POSTOPERATIVE CARE
■ For direct nerve repairs, splinting in a position that keeps the nerve repair
under no tension should be considered for 2 weeks.
■ For nerve reconstructions under no tension, splinting for 2 weeks is optional.
A soft dressing is recommended when there is no tension.
■ If immobilization is used, range of motion (ROM) begins at 2 weeks.
■ Nerve regeneration begins after a period of 30 days and from this point on
continues at a rate of 1 mm/d, 1 in./mo, and 1 ft./y.
■ The surgeon should follow the patient for signs of distally migrating sensory
recovery and strength testing for motor reinnervation.
■ Based on the distance from repair site to distal nerve endings, the surgeon can
calculate at what point the patient should begin to experience noticeable
recovery, and follow the Tinel sign along the path of the nerve.
■ If the Tinel sign ceases to cross the repair site, consideration should be given
to repeat exploration, neurolysis, possible neuroma excision, and grafting.
OUTCOMES
■ Positive predictors of sensory recovery include age and time since repair, and
data show trends consistent with better outcomes for sharp injuries.
■ There is no association between delay in repair and outcome for sensory
injuries.8
■ For mixed nerve injuries, time to repair is critical as the motor endplates will
cease to function after 18 to 24 months, and worse outcomes are seen after a
delay in repair of more than 6 to 12 months.9
■ Similarly, the distance from the injury to the target muscle is an important
determinant of outcome.
■ The surgeon may calculate the distance from the injury from the target
muscle and determine the time it will take for reinnervation to commence.

■ A commonly reported “satisfactory” result is seen as recovery of M4 (active
movement against resistance) or M5 (full power) for motor, and sensation
S3+ (static two-point discrimination of 7–11 mm).10
■ When grafting is required, the results of allograft and autograft nerve appear at
this time to be equivalent.
COMPLICATIONS
■ Complications of nerve repair are primarily inadequate recovery of sensation
or motor function and neuroma formation.
■ For inadequate sensory recovery, exploration with neurolysis and possible
neuroma excision and grafting may be indicated, although there is no urgency
to perform this.
■ For suboptimal recovery of motor function, either nerve or tendon transfers
may be indicated depending on the nerve injured and the time since injury.
REFERENCES
1. Slutsky DJ. A practical approach to nerve grafting in the upper extremity.
Atlas Hand Clin. 2005;10:73-92.
2. Planitzer U, Steinke H, Meixensberger J, et al. Median nerve fascicular
anatomy as a basis for distal neural prostheses. Ann Anat. 2014;196(2-3):144-
149.
3. Chow JA, Van Beek AL, Bilos ZJ, et al. Anatomical basis for repair of ulnar
and median nerves in the distal part of the forearm by group fascicular suture
and nerve-grafting. J Bone Joint Surg Am. 1986;68(2):273-280.
4. Landau WM. The duration of neuromuscular function after nerve section in
man. J Neurosurg. 1953;10:64.
5. Chaudhry V, Cornblath DR. Wallerian degeneration in human nerves: serial
electrophysiological studies. Muscle Nerve. 1992;15:687.
6. Stančić MF, Mićović V, Potočnjak M, et al. The value of an operating
microscope in peripheral nerve repair: an experimental study using a rat model
of tibial nerve grafting. Int Orthop. 1998;22(2):107-110.
7. Strauch B, Goldberg N, Herman CKJ. Sural nerve harvest: anatomy and
technique. J Reconstr Microsurg. 2005;21(2):133-136.
8. Mermans JF, Franssen BB, Serroyen J, Van der Hulst RWJ. Digital nerve
injuries: a review of predictors of sensory recovery after microsurgical digital
nerve repair. Hand. 2012;7:233-241.
9. Kabak S, Halici M, Baktir A, et al. Results of treatment of the extensive volar

wrist lacerations: ‘the spaghetti wrist.’ Eur J Emerg Med. 2002;9(1):71-76.
10. He B, Zhu Z, Zhu Q, et al. Factors predicting sensory and motor recovery
after the repair of upper limb peripheral nerve injuries. Neural Regen Res.
2014;9(6):661-672.

31
CHAPTER
Tendon Transfers for
Median Nerve Injury
Rafael J. Diaz-Garcia and Kevin C. Chung
DEFINITION
■ Median nerve palsy refers to the loss of motor control and sensation of the
hand in the distribution of the median nerve.
■ Low median nerve palsy refers to the loss of motor control and sensation of
the hand in the distribution of the median nerve. Loss of sensation is the
greatest deficit, because it encompasses 70% of the palmar surface. Loss of
thenar function, particularly opposition, warrants reconstruction consideration.
■ High median nerve palsy has significantly greater disability than does low
median palsy due to the variable loss of function in the forearm, which can
include pronation and flexion of the thumb, index, and long fingers.
ANATOMY
■ The median nerve is a mixed nerve composed of fibers from the C5 through
T1 roots, forming as a confluence of the lateral and medial cords of the brachial
plexus.
■ It travels with the brachial artery in the upper arm, between the biceps brachii
and brachialis. It crosses anteriorly to the vessel as it reaches the antecubital
fossa. It enters the forearm between the two heads of the pronator teres,
innervating it.
■ The median nerve travels between the flexor digitorum superficialis (FDS) and
flexor digitorum profundus (FDP) in the forearm. It gives off a branch, the
anterior interosseous nerve, to innervate the flexor pollicis longus, the radial ½
of FDP, and pronator quadratus.
■ The median nerve proper innervates the flexor carpi radialis, FDS, and
palmaris longus.

■ The palmar cutaneous branch arises 5 cm proximal to the wrist joint,
supplying the skin of the thenar eminence.
■ The median nerve passes superficially in the carpal tunnel, before giving the
recurrent motor branch from the central or radial portion of the nerve. It
usually passes distal to the transverse carpal ligament. It passes through the
transverse carpal ligament up to 7% of the time.1 The motor branch goes to the
opponens pollicis, abductor pollicis, and the superficial head of the flexor
pollicis brevis.
■ The sensory branches provide sensation to the radial 3½ digits of the hand.
■ Martin-Gruber and Riche-Cannieu connections represent anomalous
innervation patterns between the median and ulnar nerves, which may
complicate the findings on exam.
PATHOGENESIS
■ The pathogenesis of median nerve palsy is most frequently due to
compression, attributed usually to long-standing carpal tunnel syndrome.
■ Median nerve lacerations happen most commonly at the wrist due to the
superficial position of the nerve.
■ Lipofibrohamartoma of the median nerve can be seen in pediatric cases.2
■ Systemic conditions such as Charcot-Marie-Tooth disease can also cause
median neuropathy.3
■ The pathogenesis of high median nerve palsy is most frequently caused by
trauma, which can happen from injuries extending from the brachial plexus to
the forearm.
■ Compression can also cause high median nerve palsy, though it is much more
frequently the cause of low median nerve palsy. Sites of proximal compression
include the pronator teres, lacertus fibrosis, and supracondylar process.
NATURAL HISTORY
■ Compressive causes can have insidious onset symptoms over the period of
years or even decades.
■ Traumatic cases have a clearer history because of the abrupt onset of sensory
disturbance that is noticed by the patient.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Acute injury
■ Patients present with a history of trauma and often a laceration, usually in the

volar wrist.
■ Patients present with diminished sensation in the radial 3½ digits of the hand
and a positive Tinel sign at the level of injury. There is greater functional loss
with high median nerve palsy. There is a loss of opposition, flexion of the
thumb through long fingers, and potentially pronation.
■ Palmar abduction may still be present from the intact abductor pollicis
longus.
■ Chronic compression
■ Patients present with pain, numbness, and paresthesias of the radial 3½ digits.
■ In carpal tunnel syndrome, symptoms may be exacerbated during sleep or
activities that require wrist flexion, such as driving or keyboard use.
■ They often complain of “clumsiness” or difficulty with fine motor functions.
■ The most notable finding on physical exam in long-standing low median
palsy is thenar atrophy.
■ In pronator syndrome, symptoms may be exacerbated with compression of
the proximal forearm over the pronator teres.
■ Inability to make an “OK” sign with the thumb and index finger reflects
pathology involving the anterior interosseous nerve.
■ Lack of pronation reflects pathology proximal to the elbow
IMAGING
■ Initial workup for acute median nerve palsy may warrant x-rays to determine if
there are any fractures or dislocations in the extremity associated with the acute
trauma.
■ Nerve conduction studies and electromyography may be helpful in the workup
of compressive median neuropathy, helping to determine the level of the lesion.
■ Motor and sensory latencies are often increased with chronic compression of
the median nerve. Fibrillation potentials indicate denervation of the muscles
tested and axonal loss.
■ MRI of the brachial plexus may be warranted if there is concern for a lesion at
this level.
DIFFERENTIAL DIAGNOSIS
■ Carpal tunnel syndrome
■ Isolated median nerve injury
■ Anterior interosseous syndrome
■ Pronator syndrome

■ Cervical radiculopathy
■ Leprosy
■ Charcot-Marie-Tooth disease
■ Brachial plexus lesion
NONOPERATIVE MANAGEMENT
■ Nonoperative management is indicated in the setting of a brachial neuritis
(Parsonage-Turner syndrome), presenting with anterior interosseous nerve
dysfunction.
■ Work modification may be warranted in a patient with compressive
neuropathy secondary to over use in pronator syndrome.
■ Thumb adduction contractures must be prevented or treated prior to tendon
transfers, as maximum passive motion must be acquired before any tendon
transfers.
SURGICAL MANAGEMENT
■ There are three key functions that tendon transfers must address in the setting
of high median nerve palsy:9,10
■ Thumb opposition
■ Flexion of the thumb
■ Flexion of the index and long fingers
■ Occasionally, lack of pronation may require biceps rerouting. However,
shoulder abduction can often compensate for this deficit enough to not be an
issue.
■ Unlike nerve transfers, tendon transfers do not have a firm time period in
which they must be performed. Tendon transfers can be delayed while awaiting
potential nerve recovery.
■ The common principles of tendon transfers are as follows:
■ Joint contractures should be treated prior to any transfers.
■ Each muscle transfer should target one specific function.
■ Transferred tendons should glide through a smooth and scar-free surgical
site.
■ Thumb opposition cannot be reconstructed using FDS or palmaris longus in
the setting of high median nerve palsy, as it would be in low median nerve
palsy. Examination should be able to determine whether these muscles are
functional.8
■ In isolated low median nerve palsy, all reconstruction options are available. In

general, using the extensor indicis proprius is our first choice given the
negligible donor morbidity and excellent tendon excursion. The Camitz
transfer (palmaris longus) is a good option for elderly patients with long-
standing carpal tunnel syndrome. It is simple to execute at the time of carpal
tunnel release but creates more palmar abduction than true opposition. The
Huber transfer (abductor digiti minimi) is reserved for children and for
combined high median and radial nerve palsies.
Preoperative Planning
■ Tendon transfers should be delayed until after potential nerve recovery is
completed.
■ Clinical exam of the patient will allow the surgeon to decide what functions
must be recreated and what donor muscles are available for each function.
Positioning
■ The patient is placed in the supine position with a tourniquet on the upper arm.
■ The OR lights are positioned with one projecting from proximally and one
distally from the operative site.
Approach
■ Like with all tendon transfers, one should plan for the tendons to glide through
a smooth and scar-free wound bed and each transfer should be for one function.
If there is scarred tissue along the path of the transfer, it must be replaced by
soft supple tissue either through serial scar excision or a flap procedure.
T E C H N I Q U E S
■ Low Median Nerve Injury: Reconstruction of
Thumb Opposition
Palmaris Longus to Abductor Pollicis Brevis (Camitz Transfer)
■ Confirm the presence of a palmaris longus (PL) tendon and design a
longitudinal incision, from the distal wrist crease to the proximal palmar
crease, with a Bruner design over the wrist joint (TECH FIG 1A).
■ Dissect the palmaris longus distally, taking a patch of palmar aponeurosis

along with the tendon (TECH FIG 1B).
■ Make an incision over the dorsoradial aspect of the thumb
metacarpophalangeal (MCP) joint.
■ Create a subcutaneous tunnel between the PL tendon and the MCP joint with
blunt dissection.
■ Pass the PL tendon to the thumb incision and suture it to the abductor
pollicis brevis (APB) tendon (TECH FIG 1C,D) and extensor hood.
Flexor Digitorum Superficialis to Abductor Pollicis Brevis
(Bunnell Transfer)
■ A transverse incision is made over the ring finger A1 pulley (TECH FIG
2A).
■ The A1 pulley is exposed and divided longitudinally, preserving the
neurovascular bundles.
■ The flexor digitorum superficialis (FDS) is divided proximally to the
bifurcation with proximal longitudinal traction.
■ A Bruner or longitudinal incision is made over the ulnar wrist, just radial to
the flexor carpi ulnaris (FCU) tendon and near its insertion.

TECH FIG 1 • A. Design of incisions for PL transfer to
AP. B. Exposure of PL at insertion into palmar fascia.
C. PL tendon is sutured to APB, creating palmar
abduction. D. PL tendon is sutured to APB, creating
palmar abduction.
TECH FIG 2 • A. Tendon anatomy for FDS to APB
(Bunnell) transfer. B. Looping of the FCU tendon to
create a pulley for transfer. C. Passage of FDS tendon
through the FCU pulley for suture to the APB tendon.
■ The radial half of the FCU tendon is divided and separated from the ulnar
half longitudinally.
■ The distally based FCU tendon is sutured to itself at the insertion site,
creating a pulley (TECH FIG 2B).
■ A longitudinal incision is made along the radial aspect of the thumb MCP

joint.
■ A subcutaneous tunnel is created from the thumb incision to the wrist
incision.
■ The FDS is passed through this pulley and then through the tunnel to the
thumb, where it is sutured to the APB tendon and extensor hood with braided
suture (TECH FIG 2C).
Abductor Digiti Minimi to Abductor Pollicis Brevis (Huber
Transfer)
■ A Bruner or curvilinear incision is made from the ulnar aspect of the small
finger to the radial border of the hypothenar eminence (TECH FIG 3A).
■ The abductor digiti minimi (ADM) is dissected distally, protecting the ulnar
neurovascular bundle to the small finger. It is freed from the underlying
flexor digiti minimi, if present (TECH FIG 3B).
■ The ADM is released from its insertion site on the small finger proximal
phalanx with a portion of the lateral band to increase its length.
■ From distal to proximal, mobilize the muscle toward and eventually off of
the pisiform. Preserve the neurovascular bundle, which comes from the deep
and radial surface of the muscle (TECH FIG 3C).
■ Make an incision along the radial aspect of the thumb MCP joint and use
blunt dissection to create a subcutaneous tunnel in the palm, superficial to the
transverse carpal ligament.
■ Pass the ADM through the tunnel to the thumb and suture it to the APB
tendon and extensor hood with permanent braided suture (TECH FIG 3D).

TECH FIG 3 • A. Design of incisions for ADM transfer
to APB. B. Exposure of ADM along hypothenar
eminence. C. Dissected free ADM muscle, all the way
to pisiform. D. Final position after transfer, creating
both palmar abduction and opposition.
■ High Median Nerve Injury
Reconstruction of Thumb Opposition: Extensor Indicis
Proprius to Abductor Pollicis Brevis
■ A small longitudinal incision is made along the dorsoulnar aspect of the
index MCP joint (TECH FIG 4A).
■ The extensor indicis proprius (EIP) tendon is identified as the ulnar tendon
and released from the index finger extensor hood with a small slip of
extensor mechanism. The rent is repaired with permanent suture.
■ A longitudinal incision is made over the dorsoulnar wrist, just proximal to
the ulnar styloid.
■ Dissection is carried radially from this wrist incision to find the EIP tendon,
just distal to the extensor retinaculum. The distal aspect of the fourth extensor
compartment is divided to fully mobilize the tendon.
■ A small incision is made along the radial pisiform and a longitudinal incision
along the radial aspect of the thumb MCP (TECH FIG 4B).

■ A subcutaneous tunnel is created from the dorsal wrist incision to the
pisiform incision, attempting to stay deep to the ulnar sensory nerve branch.
This tunnel is then dissected from the pisiform to the thumb incision.
TECH FIG 4 • A. Release of EIP tendon for passage
and radial dissection to locate and retrieve EIP tendon
for transfer. B. Creation of a subcutaneous tunnel from
the radial pisiform incision to the longitudinal thumb
incision. C. EIP suture to APB tendon with braided
permanent suture.
■ The EIP tendon is passed from dorsal to volar, around the pisiform, and then
to the thumb incision. It is sutured to the APB tendon and extensor hood with
braided permanent suture (TECH FIG 4C).
Reconstruction of Index and Long Finger Flexion: Flexor
Digitorum Profundus Side-to-Side Transfer
■ A longitudinal incision is made over the distal third of the forearm.
■ The flexor digitorum profundus (FDP) tendons are identified, deep to the
median nerve (TECH FIG 5A).
■ The FDP tendons are synchronized to recreate the digital cascade, and one

sutures the index through small finger tendons with two rows of braided
permanent sutures (TECH FIG 5B).
Reconstruction of Thumb Flexion: Brachioradialis to Flexor
Pollicis Longus
■ A longitudinal incision is made along the distal third of the forearm. The
same incision for the FDP transfer can be used (TECH FIG 6A).
■ The brachioradialis (BR) is released from the radial styloid insertion and
mobilized proximally to maximize the excursion (TECH FIG 6B).
■ The FPL tendon is located under the flexor carpi radialis, in the deep volar
compartment.
■ The BR is weaved into the flexor pollicis longus (FPL) with multiple passes,
after optimizing tension (TECH FIG 6C,D). Wrist extension should result in
maximal thumb IP joint flexion and lateral pinch.
TECH FIG 5 • A. The FDP tendons are localized
beneath the median nerve in the distal forearm. B.
Tension is set between the radial two tendons (median
innervated) and ulnar two tendons (ulnar innervated),
recreating the digital cascade.

TECH FIG 6 • A. Design of incisions for high median
nerve tendon transfers. B. Exposure of BR along
insertion onto radial styloid. C. Tension is set between
the BR and FPL. D. Final position of thumb after
transfer, judging tenodesis with wrist flexion and
extension.
PEARLS AND PITFALLS
Preoperative
evaluation
■ Critically assess donor muscle availability and strength.
■ Determine patient goals and potential for additional nerve
recovery.
■ Release any areas of nerve compression for pain control, even if
motor recovery is unlikely.
Thumb
opposition
■ Thumb should be in full opposition and IP joint flexed with wrist
extension and should relax with wrist flexion.
■ Ensure that subcutaneous tunnel is of ample size to allow easy
tendon gliding.
Finger flexion
■ Improvement in finger flexion may not improve grip strength
given no additional motor units.
POSTOPERATIVE CARE

■ Patient is usually splinted with the thumb in full opposition and wrist in
flexion immediately after surgery. The fingers are free to move to maintain
motion.
■ At the first postoperative visit, an orthoplast splint is fabricated to maintain
thumb opposition and slight wrist flexion. At 3 weeks, gentle active range of
motion is commenced several times a day. Passive range of motion is started at
6 weeks. Strengthening is started at 8 weeks.
■ A knowledgeable hand therapist plays an important role in the surgical
outcomes.
■ Early active range of motion for opposition transfers has been advocated by
some surgeons, with quicker recovery and no evidence of pullout of the
transferred tendon.4
OUTCOMES
■ Most median nerve palsy patients can perform normal activities of daily living
with their hand after complete recovery from surgery. The tendon transfers
combine proper direction of action, pulley location, and force for success.5
■ Extensor indicis proprius (EIP) opponensplasty is generally efficacious, with
88% of patients with excellent results—ie, 75% function of the opposite,
normal thumb.6 It works best in the setting of supple hands.7 EIP is not
synergistic with thumb opposition, so retraining can be more difficult than FDS
transfers.
COMPLICATIONS
■ Suboptimal results may be a result of choosing a weak motor for transfer or
incorrect vector of pull.
■ Tendon adhesions can result from prolonged immobilization, particularly if
using a pulley to reroute the force of the muscle.
■ Tendon ruptures can be prevented with patient education and progressive
therapy advancement.
REFERENCES
1. Kozin SH. The anatomy of the recurrent branch of the median nerve. J Hand
Surg Am. 1998;23(5):852-858.
2. Biazzo A, Gonzalez Del Pino J. [Paralysis of the median nerve due to a
lipofibrohamartoma in the carpal tunnel]. Rev Esp Cir Ortop Traumatol.
2013;57(4):286-295.

3. Michelinakis E, Vourexakis H. Tendon transfer for intrinsic-muscle paralysis
of the thumb in Charcot-Marie Tooth neuropathy. Hand. 1981;13(3):276-278.
4. Rath S. Immediate active mobilization versus immobilization for opposition
tendon transfer in the hand. J Hand Surg Am. 2006;31(5):
754-759.
5. Cooney WP. Tendon transfer for median nerve palsy. Hand Clin. 1988;
4(2):155-165.
6. Burkhalter W, Christensen RC, Brown P. Extensor indicis proprius
opponensplasty. J Bone Joint Surg Am. 1973;55(4):725-732.
7. Anderson GA, Lee V, Sundararaj GD. Opponensplasty by extensor indicis and
flexor digitorum superficialis tendon transfer. J Hand Surg Br. 1992;17(6):611-
614.
8. Jacobs B, Thompson TC. Opposition of the thumb and its restoration. J Bone
Joint Surg Am. 1960;42A:1015-1026.
9. Sammer D, Chung KC. Tendon transfers, part II: transfers for ulnar nerve
palsy and median nerve palsy. Plast Reconstr Surg. 2009;124(3):
212e-221e.
10. Ratner JA, Peljovich A, Kozin SH. Update on tendon transfers for peripheral
nerve injuries. J Hand Surg [Am]. 2010;35:1371-1381.

32
CHAPTER
Tendon Transfers for Ulnar
Nerve Injury
Rafael J. Diaz-Garcia and Kevin C. Chung
DEFINITION
■ Ulnar nerve palsy refers to the loss of motor control and sensation in the
distribution of the ulnar nerve.
■ Low ulnar nerve palsy refers to isolated loss of intrinsic hand function,
whereas high ulnar nerve palsy refers to the additional loss of half the flexor
digitorum profundus (FDP) and flexor carpi ulnaris (FCU).
ANATOMY
■ The ulnar nerve is a mixed nerve composed of fibers from the C8 and T1 roots
via the medial cord of the brachial plexus.
■ It lies posteromedial to the brachial artery in the upper arm, prior to piercing
the intramuscular septum 8 to 10 cm proximal to the medial epicondyle. It has
no branches in the arm.
■ It passes through the cubital tunnel into the forearm, running between FCU
and FDP, innervating the former and 0.5 of the latter.
■ Approximately 6 to 7 cm proximal to the ulnar styloid, the dorsal sensory
branch leaves the main nerve to innervate the dorsoulnar hand and dorsal
proximal phalanges of the small and ring fingers.
■ The ulnar nerve continues into the hand through the Guyon canal at the wrist,
splitting into a superficial sensory branch and a deep motor branch. The
sensory branch supplies innervation to the small finger and ulnar half of the
ring finger. The motor branch supplies the hypothenar muscles, ulnar
lumbricals, interossei, adductor pollicis, and the deep head of flexor pollicis
brevis.
■ Martin-Gruber and Riche-Cannieu connections represent anomalous

innervation patterns between the median and ulnar nerves, which may
complicate the findings on exam.
PATHOGENESIS
■ The pathogenesis of ulnar nerve palsy is most frequently secondary to trauma.
Injury may come in the form of a laceration along its course, an axonotmetic
injury, or an avulsion of the roots. Proximal injuries that involve the medial
cord may also have sensory disturbances in the arm or forearm due to
involvement of the medial brachial and antebrachial cutaneous branches.
■ Systemic conditions such as Charcot-Marie-Tooth disease, leprosy, and
syringomyelia can cause ulnar neuropathy as well.1 Systemic conditions are
unlikely to present with isolated ulnar nerve symptoms.
NATURAL HISTORY
■ With prolonged ulnar nerve palsy, secondary deformities of the hand will
develop with attenuation of the central slips and flexion contractures of the
interphalangeal joints.
■ The disability and deformity is directly related to the degree of the nerve
injury. If tendon transfers are being considered, nerve recovery is unlikely.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ It is important to identify the cause and timing of ulnar nerve palsy to
determine if the pathology can be reversed. Acute repair of lacerated nerves,
nerve transfers, and decompressions should be done sooner rather than later to
prevent irreversible loss of the motor end plates in the innervated muscles.
■ Tendon transfers are indicated when no further recovery of the nerve or the
ulnarly innervated muscles is expected.
■ Working from distal to proximal, testing muscle and sensory function can help
localize the level of the lesion. The first dorsal interosseous is the last muscle
innervated by the ulnar nerve. Involvement of only motor function implies a
lesion in the deep motor branch, distal to the Guyon canal. Loss of sensation
along the dorsoulnar aspect of the hand implies a lesion proximal to the takeoff
of the dorsal sensory branch. Loss of distal interphalangeal (DIP) flexion of the
ring and small fingers implies high ulnar nerve palsy, due to involvement of the
FDP. Loss of sensation along the medial arm or forearm implies a lesion in the
brachial plexus.
■ There are many eponymous physical findings found in ulnar nerve palsy, most

of which are functional losses of intrinsic hand muscles:2,3
■ Froment sign: hyperflexion of the IP joint of the thumb when attempting
forceful adduction, due to substitution of flexor pollicis longus (FPL) for
adductor pollicis
■ Jeanne sign: hyperextension of the metacarpophalangeal (MCP) joint of the
thumb as a reciprocal result of over use of FPL
■ Wartenburg sign: abduction of small finger due to paralysis of intrinsics with
unimpeded abduction by extensor digiti minimi
■ Duchenne sign: hyperextension of the MCP joints and flexion of the PIP
joints, secondary to paralysis of ulnarly innervated interosseous and
lumbricals
■ Masse sign: flattening of the metacarpal arch
■ Pollack sign: loss of DIP flexion of the ring and small fingers in high ulnar
nerve palsy
■ The Bouvier maneuver is a preoperative test to assess IP joint extension if
MCP hyperextension is blocked. In theory, a positive Bouvier—that is to say,
intact IP extension with MCPs held in flexion—implies that addressing MCP
hyperextension with a static procedure should correct claw deformity. In
reality, static soft tissue procedures tend to stretch out and most patients would
do best with a dynamic tendon transfer.4
IMAGING
■ Initial workup for an ulnar nerve lesion usually warrants nerve conduction
studies and electromyography to determine location and extent of injury.
■ MRI of the brachial plexus may be warranted if there is concern for a lesion at
this level.
DIFFERENTIAL DIAGNOSIS
■ Isolated ulnar nerve compression
■ Isolated ulnar nerve injury
■ Traumatic lower plexopathy
■ Cervical radiculopathy
■ Leprosy
■ Syringomyelia
NONOPERATIVE MANAGEMENT
■ An occupational therapist can be helpful in the nonoperative management of

ulnar nerve palsy.
■ An anticlaw splint (dorsal blocking at the MCP joint with IP joints free) can be
used to preserve extensor integrity while the nerve recovers or as a long-term
functional orthosis.
■ Flexion contractures must be prevented or treated prior to tendon transfers, as
maximum passive motion must be acquired before any tendon transfers.
■ Fixed flexion contractures should be addressed with serial casting, if needed.
SURGICAL MANAGEMENT
■ There are three key functions that tendon transfers must address in the setting
of ulnar nerve palsy:
■ Thumb adduction to recreate key pinch
■ Improved grip by addressing claw deformity and MCP hyperextension
■ Flexion of ring and small finger DIP joints, in those with a high ulnar palsy
■ Unlike nerve transfers, tendon transfers do not have a firm time period in
which they must be performed. Tendon transfers can be delayed while awaiting
potential nerve recovery.
■ The common principles of tendon transfers are as follows:
■ Joint contractures should be addressed prior to any transfers.
■ Each muscle transfer should address one specific function.
■ Transferred tendons should glide through a smooth and scar-free surgical
site.
■ Thumb adduction can be addressed with either extensor carpi radialis brevis
(ECRB) or flexor digitorum superficialis (FDS), with the former being our
preference. Transfers for adduction require a pulley distal to the pisiform for
the transfer to be effective.
■ Claw deformity of the fingers can be addressed with either static or dynamic
procedures. For static procedures to be indicated, the Bouvier maneuver must
be positive. Static procedures prevent hyperextension of the MCP joint but
often stretch out over time unless the joint undergoes arthrodesis.5 Dynamic
procedures use FDS, ECRB, extensor carpi radialis longus, or flexor carpi
radialis. The FDS transfers are preferable because they do not require tendon
grafts, which may be prone to adhesion. High ulnar nerve palsy precludes use
of the FDS tendons in the ring and small finger for transfers.
Preoperative Planning
■ Tendon transfers should be delayed until after potential nerve recovery is

completed.
■ Clinical exam of the patient will allow the surgeon to decide what functions
must be recreated and what donor muscles are available for each function.
Positioning
■ The patient is placed in the supine position with a tourniquet on the upper arm.
■ The OR lights are positioned with one projecting from proximally and one
distally from the operative site.
Approach
■ Like with all tendon transfers, one should plan for the tendons to glide through
a smooth and scar-free wound bed and each transfer should be for one function.
■ To recreate the intrinsic function of the hand, the transferred tendons should
pass volar to the axis of the MCP joint prior to inserting on the dorsal extensor
apparatus.
T E C H N I Q U E S
■ Claw Deformity of Digits
Metacarpal Capsulodesis6,7
■ Indicated only with a positive Bouvier maneuver
■ An incision is made in line with the distal palmar crease, over the A1 pulley
of the ring and small fingers.
■ The A1 pulley is exposed and released longitudinally, protecting the
neurovascular bundles and exposing the volar plate of the MCP joint (TECH
FIG 1).
■ A distally based, rectangular-shaped flap of volar plate is created by
releasing the proximal attachment off the metacarpal.
■ A 30-degree flexion contracture is created with the volar plate advanced
proximally, and bone anchors are used to maintain position of the joint.
■ As noted before, this procedure can be technically difficult to perform
because the exposure is limited and the volar plate cannot be advanced easily.
This type of soft tissue reconstruction does stretch out rather quickly. A truly
predictable static procedure is MCP joint fusion.

Flexor Digitorum Superficialis Lasso
■ An incision is made in line with the distal palmar crease, over the A1 pulleys
of the ring and small fingers.
■ The A1 and A2 pulleys are exposed, preserving the neurovascular bundles.
■ The FDS insertion is preserved to reduce the likelihood of a swan-neck
deformity. The FDS is released at A2 pulley and sutured back to itself
proximal to the A1 pulley, creating a tendinous loop (TECH FIG 2A).
■ Set the tension with the MCP joint at 40 to 50 degrees of flexion with the
wrist at neutral, recreating the usual digital cascade of the hand (TECH FIG
2B).
■ The FDS middle finger can be split into four tails in a more proximal
incision and similarly tensioned at each A1 pulley.
TECH FIG 1 • A1 pulley is released longitudinally and
a rectangular-shaped flap of volar plate is created.
Flexion contracture is created with the proximally
advanced volar plate and bone anchors maintain
position of the joint.

Stiles-Bunnell Transfer of FDS to Lateral Bands8,9
■ One FDS tendon can be used to power two digits or four digits. The ring and
small finger FDS is not used in the setting of high ulnar nerve palsy to
preserve flexion of the ring and little fingers when the FDP to these two
fingers is paralyzed.
■ A Bruner incision is made over the proximal phalanx between the A2 and
A3 pulleys. A separate longitudinal incision is made over the proximal
phalanx between the glabrous and nonglabrous skin to expose the radial
lateral band (TECH FIG 3A).
■ The FDS is divided just proximal to the insertion and split into four slips as
proximally as possible (TECH FIG 3B).
TECH FIG 2 • A. FDS tendon is released at distal
edge of A2 pulley via Bruner incision. B. FDS tendon
is sutured back to itself to create a flexion contracture
at MCP joint.

TECH FIG 3 • A. The FDS of the middle finger is
released from the insertion on middle phalanx. B. Four
tails are created for transfer to the digits. C. FDS is
transferred to the lateral bands of each digit, radial of
the middle-small and ulnar of the index. D. Final
position after transfer shows MCP flexion composite
with FDS pull.
■ FDS slip is passed through lumbrical canal, deep to the neurovascular
bundle, with a tendon passer or hemostat to the radial aspect of the middle
through small fingers and the ulnar aspect of the index. It is key to stay
palmar to the deep metacarpal ligament to maintain the force palmar to the
axis of rotation (TECH FIG 3C).
■ FDS slips are attached to the lateral band with the wrist at neutral, trying to
recreate the digital cascade. MCP flexion should be at 50 to 70 degrees and
IP joints in full extension (TECH FIG 3D).
■ Passive wrist flexion should result in full MCP extension.
ECRB to Lateral Bands With Tendon Graft9,10

■ ERCB is used when the FDS is not available, for example, high median and
ulnar nerve palsy when the reinnervated median nerve muscles are too weak
to transfer.
■ A small transverse incision is made over the third metacarpal base, through
which the ECRB is transected at its insertion.
■ The ECRB tendon is retrieved proximal to the retinaculum through a
separate incision.
■ Incisions are made at the metacarpal necks in the second/third metacarpal
interval and fourth/fifth metacarpal interval.
■ Excising a small window of paralyzed interosseous muscle creates a path
for each tendon graft.
■ Longitudinal incisions are made over the proximal phalanges of the index
through small fingers, exposing the lateral bands.
■ A tendon graft is passed volarly to the intermetacarpal ligament and through
the intermetacarpal windows.
■ The tendon grafts are sutured to the radial lateral bands of the middle
through small fingers and the ulnar lateral band of the index.
■ The grafts are sewn to each other and then to the ECRB (TECH FIG 4).
■ Tension should be done with the wrist in full extension and the fingers in
an intrinsic-plus position.
■ MCP extension should happen with wrist flexion.

TECH FIG 4 • A. Tendon graft is passed volarly to the
intermetacarpal ligament and through the
intermetacarpal windows. B. Tendon grafts are