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ULNAR NERVE PALSY AND TRANSFERS

Introduction

Ulnar nerve palsy is a condition resulting from damage to the ulnar nerve at any point along its anatomical length. It results in more severe impairments than radial nerve palsy but is not as devastating as median nerve palsy. Cases are classified based on their location, with high ulnar nerve palsy describing injuries proximal to the elbow and low ulnar nerve palsy describing injuries distal to the elbow. Both high and ulnar nerve palsy typically result in some degree of clawing—which is more severe in high ulnar nerve palsy—and sensory loss, which can be clinically disabling. A tendon transfer is a surgical procedure used to treat ulnar nerve palsy that usually involves the release of a tendon at its anatomic insertion site, rerouting the tendon, and finally reattaching it to a new insertion site either in another tendon or in a bone. It is a commonly used procedure that may be needed for non-repairable ulnar nerve injuries, when there is a loss of muscle and tendon secondary to trauma, or for slowly progressing neurological disease.1-3

Related Anatomy1,4

  • Ulnar nerve
    • Terminal branch of the medial cord of the brachial plexus
    • Travels through cubital tunnel at the elbow, then passes between the two heads of the flexor carpi ulnaris (FCU), which it innervates
    • Innervates the flexor digitorum profundus (FDP) of the fourth and little fingers as it courses distally from the elbow
    • Gives off dorsal sensory branch ~7 cm proximal to the wrist, which provides sensibility to the dorsal ulnar aspect of the hand
    • Within Guyon’s canal, it divides into a deep motor and superficial branch
      • Deep motor branch innervates hypothenar muscles, ulnar two lumbricals, the interossei, adductor pollicis, and deep head of the flexor pollicis brevis (FPB)
      • Superficial branch: gives sensibility to the little finger and ulnar half of the ring finger

Signs and Symptoms1,5

  • Typical symptoms of ulnar nerve palsy include:
    • Loss of key pinch
    • Impaired grip strength/inability to stabilize the wrist during power grip
    • Clawing
      • Results from loss of active interphalangeal (IP) joint extension and metacarpophalangeal (MP) joint flexion
    • Loss of the integration of IP and MP joint flexion
    • Loss of ulnar deviation with wrist flexion
    • Loss of sensation in the ulnar third of the palm and the ring and little fingers

Is more clinically disabling than the loss of sensation in radial nerve palsy

  • A tendon transfer is usually indicated when there is no potential for ulnar nerve injuries to improve, including those that are physically irreparable (e.g. root avulsions, injuries not improved after direct nerve repair or grafting, and failed nerve transfers)
  • Other indications for tendon transfer include:
    • Ulnar nerve palsies that present too late for muscle reinnervation to occur due to fibrosis of the motor end plate
    • Loss of muscle or tendon following trauma
    • Central neurologic deficits

Physical Examination and Work-up2,4,6

  • Before considering a patient for a tendon transfer, the clinician should obtain an accurate history and perform a physical examination
  • The physical examination includes detailed muscle testing and range of motion (ROM) assessments of the wrist, hand, and finger. An inventory of both the functioning and nonfunctioning muscle-tendon units should be performed.
    • Both motor function and sensation must be evaluated to identify any deficits present, distinguish between lesion types, and determine appropriate indications for correction
      • The thumb’s carpometacarpal (CMC), metacarpophalangeal (MP), and IP joint should all be carefully assessed and compared with the contralateral side
    • Detailed examinations go to muscle testing by nerve or to specific muscle examinations in the exam test and signs section
    • Specific tests for ulnar nerve palsy include:
      • Froment’s sign
        • Hyperflexion of the thumb IP joint during a grabbing motion
      • Jeanne’s sign
        • Reciprocal hyperextension of the thumb MP joint
      • Wartenberg’s sign
        • Abduction of the little finger at the MP joint
      • Duchenne’s sign
        • Clawing of the fourth and little fingers, hyperextension of the MP joints and flexion of the PIP joints
      • Bouvier’s test
  • Ulnar nerve palsies can usually be diagnosed by the physical exam alone, but electrodiagnostic testing may also be needed
    • Electromyography (EMG) and nerve conduction velocity (NCV) testing can be used for determining the exact location and extent of the initial injury, and to rule out other diagnoses
    • EMG and NCV testing can also be helpful for detecting signs of early nerve recovery

Basic Science and Principles of Tendon Transfers

  • When evaluating a patient for a tendon transfer and planning out the procedure, several core principles must be considered. Adhering to these principles will increase the chances of a successful outcome, while not doing so can lead to a failure. The core principles of tendon transfers are described below.7

1. Synergy2,7

  • Synergy principle: certain muscle groups usually work together to perform a function or movement (e.g. wrist flexion and finger extension; wrist extension and finger flexion)
  • Finger flexion and wrist flexion are not synergistic movements
    • Therefore, a wrist flexor transferred to restore finger extension will adhere to synergetic principles, while a wrist flexor transferred for finger flexion will not function synergistically
  • Synergistic transfers are usually easier to train and are preferable to non-synergistic transfers; therefore, it is advised to perform synergistic transfers whenever possible, although non-synergistic transfers may be the only option available in some cases

2. Passive mobile joints2,7,8

  • Tendon transfers cannot mobilize stiff joints, and the procedure will fail if a joint is too stiff
  • Passive mobility is therefore a prerequisite to tendon transfer: the joints controlled by the transferred tendon must have nearly full passive ROM before the procedure to achieve optimal post-tendon transposition
  • The donor muscles must be tested for strength before performing transfer procedures
  • Pre-operative hand therapy is often needed to improve passive ROM if it is not normal
  • In some cases, joint release may be necessary before the tendon transfer

3. Soft tissue equilibrium2,7

  • Tendon transfers must pass through a healthy bed of soft tissue that is free of scar tissue, inflammation, and edema. A healthy soft tissue bed allows the tendon to glide freely with pliable skin and minimizes adhesions
  • In most cases, this will entail the transfer passing through healthy subcutaneous fatty tissues
  • After a soft tissue injury, the surgeon must allow sufficient time to pass for inflammation and edema to fully subside before performing tendon transfers
  • If a healthy, soft bed is not present and/or the transfer must pass through an area in which severely scarred tissue is present, the surgeon can either excise the scar and reconstruct the bed with a flap or plan an alternative transfer through a healthier bed of tissue

4. Adequate strength2,7

  • The strength of the donor muscle-tendon unit being must be strong enough to allow the desired movement(s) but must not be so strong that it disrupts the extensor/flexor balance
    • When the donor is too weak, movement and function will not be adequate
    • When the donor is too strong, movements become unbalanced and there is inappropriate posture at rest
  • Therefore, the strength of the muscle-tendon unit should be either normal or near normal and under voluntary control in pre-operative testing. Strength at 5/5 is ideal because the transferred muscle will usually loose a grade after transfer.
  • For additional information see the standard muscle testing options in the examination section below

5. Sufficient amplitude9

  • A muscle’s amplitude is a function of its sarcomere length
  • The transferred muscle-tendon unit must have enough amplitude to successfully perform the function of the tendon being replaced
    • The sarcomere length and work capacity of the muscle being transferred must provide enough muscle shortening during contraction to provide adequate shortening of the muscle-tendon unit and produce the needed ROM of the joints that need to be mobilized
  • The flexor carpi ulnaris (FCU) has the greatest work capacity of the wrist motors, but due to its significant role in wrist function, using it for tendon transfers has been called into question

6. Straight line of pull7,9

  • Transferred tendons must have a straight line of pull from their origin through unscarred soft tissue to the new insertion point
  • Changes in direction can create points of friction, which reduces the potential force, power, and amplitude of the transferred muscle-tendon unit: changing direction by only 40° will lead to a significant decrease in force
  • Tendon transfers cannot perform two separate functions at once, especially if the line of pull is not straight
  • If there is a second point of insertion because the tendon has been split to insert on two separate insertion sites and half of the tendon does not follow a straight vector, then no force will be directed to this second insertion point. There are rare exceptions to this rule such as a Stiles-Bunnell intrinsic transfer. This means usually each transfer such have only one function not two.

7. Expendable donor2,7

  • The donor muscle-tendon unit must be expendable, meaning another tendon—or tendons—is left intact that can continue to adequately perform the original function of the transferred muscle-tendon unit
  • Restoring a given movement only to lose another equally important movement in the process is not beneficial
  • Example: if one of the wrist flexors (e.g. the flexor carpi radialis [FCR]) is transferred, then the FCU must be intact and functioning normally so wrist palmar flexion function is preserved after the transfer

8. Tension of the transfer7

  • The amount of passive tension set is a critical component of the procedure: the surgeon should ensure that the tension in the transfer is slightly tight and be aware of the recommended positioning of the elbow, wrist, and digits when adjusting this tightness
  • The surgeon should also use the wrist tenodesis effect to gently test the transfer passively before finalizing the tightness of the tendon transfer insertion into its new origin

9. Donor of adequate excursion2,5,7,9

  • The excursion of the donor muscle-tendon unit should be adequate enough to achieve the desired hand movement, meaning the excursion of the transferred tendon is comparable to that of the recipient tendon
  • Excursion of various muscles
    • Wrist extensors and flexors: 33 mm
    • Finger extensors: 50 mm
    • Finger flexors: 70 mm
  • The tenodesis effect of the wrist can add another 20–30 mm of finger tendon excursion

10. Single function per transfer2,5,7

  • A single tendon should only be used to restore a single function, as attempting to restore multiple functions will compromise strength and movement
  • One exception is that a single muscle-tendon unit can restore the same movement in more than one digit (see #6)

Other

  • Incisions used for tendon transfers should not parallel the route of the transferred tendon because this will increase the chance of adhesions and loss of tendon gliding
  • Use transverse incisions so there is less opportunity for the transferred tendon to scar to the surgical incision
  • Tendon transfers will often adhere to the first fibrous structures that they touch, so ideally the first fascial (collagen) structure should be at the new insertion site of the transferred tendon. This fact also means that transfers are not reliably be used to produce forearm rotation.

Timing and planning6,9

  • Timing of tendon transfers for ulnar nerve palsy is classified as either early or late
    • Early tendon transfer
      • Act as an internal splint
      • Performed within 12 weeks of injury
    • Late tendon transfer
      • Performed to restore function when recovery is unlikely
      • Can be performed between 6–18 months after injury
  • Determining the optimal timing should be contingent on several factors, including:
    • The etiology of the injury
    • The patient’s prognosis
    • Whether there is a clear indication that the injured nerve will not regenerate
    • Patient preference
  • If functional recovery is not possible, transfers should be performed immediately after the patient is ready. If nerve regeneration is expected to occur, the surgeon should wait until it’s possible to determine the level of functional recovery.
  • Planning for tendon transfers must include making an inventory of those muscle-tendon units that are functioning normally and those that are no longer functioning or have been removed by injury
  • The surgeon must do appropriate muscle testing to determine the muscle grade of each remaining muscle-tendon unit. For additional information, see the standard muscle testing options in the examination section below.  For a muscle tendon unit to be eligible for transfer, it should have a muscle testing grade of 4/5 or preferably 5/5. 

High vs. low ulnar nerve palsy1,2,5

  • High ulnar nerve palsy
    • Proximal to the elbow
    • Leads to loss of:
      • Fourth and little finger DIP flexion and MP flexion
      • Key pinch
      • Grip strength
      • Deviation with wrist flexion
      • Sensation in the ulnar third of the palm, ulnar half of the fourth finger, and both sides of the little finger
    • Clawing
  • Low ulnar nerve palsy
    • Distal to the elbow
    • Produces little finger hyperabduction
    • Leads to loss of:
      • Fourth and little finger MP flexion
      • Key pinch
      • Grip strength
      • Sensation in the ulnar half of the fourth finger and the volar aspect of the little finger
      • Normal hand contour
    • Clawing
      • Less severe than in high ulnar nerve palsy

Combined median and ulnar nerve palsy1,9

  • Challenging injuries that typically result from severe trauma and are associated with substantial soft tissue, vascular, and bony injuries
  • Multiple muscle-tendon units may be lacerated and require repair, meaning they are unsuitable donors for tendon transfer. Further complicating reconstruction is that the loss of sensibility and proprioception is usually more profound than in single nerve palsies.
  • Combined low median and ulnar nerve palsy
    • Most common combined injury
    • Typically occurs secondary to a laceration on the volar side of the wrist
    • Leads to the following symptoms:
      • Complete palmar numbness throughout the hand, fingers, and thumb
      • Clawing of all four fingers
      • Loss of finger flexion integration, key pinch, and thumb opposition
  • Combined high median and ulnar nerve palsy
    • Less common, but far more severe injury and more difficult to treat than combined low median-ulnar nerve palsy
    • Leads to the following symptoms:
      • Loss of key pinch and simple grip strength
      • Loss of finger flexion
      • Loss of thumb opposition
      • Profound loss of sensation
ICD-10 Codes

  • ULNAR NERVE PALSY AND TRANSFERS

    Diagnostic Guide Name

    ULNAR NERVE PALSY AND TRANSFERS

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    ULNAR NERVE PALSY DUE TO LESION G56.22G56.21G56.23
    ULNAR NERVE PALSY DUE TO INJURY, FOREARM LEVEL (LOW) S54.02X_S54.01X_ 
    ULNAR NERVE PALSY DUE TO INJURY, UPPER ARM LEVEL (HIGH) S44.02X_S44.01X_ 

    Instructions (ICD 10 CM 2020, U.S. Version)

    THE APPROPRIATE SEVENTH CHARACTER IS TO BE ADDED TO EACH CODE FROM CATEGORY S44 AND S54
    A - Initial Encounter
    D - Subsequent Routine Healing
    S - Sequela

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
Clinical Presentation of Ulnar Nerve Palsy
  • Ulnar Nerve Palsy with significant first dorsal interosseous atrophy (arrow)
    Ulnar Nerve Palsy with significant first dorsal interosseous atrophy (arrow)
  • Ulnar Nerve Palsy with positive Froment's sign. Note the flexion of the thumb IP, the index is supported by the other digits and the "O" sign is lost.
    Ulnar Nerve Palsy with significant first dorsal interosseous atrophy (arrow)
  • Ulnar Nerve Palsy with clawing of the fourth and fifth fingers and marked dryness of the ulnar denervated skin (anhydrous )
    Ulnar Nerve Palsy with clawing of the fourth and fifth fingers and marked dryness of the ulnar denervated skin (anhydrous )
  • Ulnar Nerve Palsy with Wartenberg sign (Note abduction contracture of fifth finger)
    Ulnar Nerve Palsy with Wartenberg sign (Note abduction contracture of fifth finger)
  • Combined Ulnar and Median Nerve Palsies. Note first dorsal interosseous atrophy (1) and hypothenar atrophy (2).
    Combined Ulnar and Median Nerve Palsies. Note first dorsal interosseous atrophy (1) and hypothenar atrophy (2).
  • Combined Ulnar and Median Nerve Palsies with ulnar intrinsic atrophy, thenar atrophy and loss of the palmar arches.
    Combined Ulnar and Median Nerve Palsies with ulnar intrinsic atrophy, thenar atrophy and loss of the palmar arches.
Basic Science Photos and Related Diagrams
Ulnar Intrinsic Weakness
Basic Science Pics
  • Ulnar Nerve Palsy with weak grip
    Ulnar Nerve Palsy with weak grip
  • Ulnar Nerve Palsy with weak pinch
    Ulnar Nerve Palsy with weak pinch
Pathoanatomy Photos and Related Diagrams
Ulnar Nerve Anatomy
  • Muscles innervated by the Ulnar Nerve.
    Muscles innervated by the Ulnar Nerve.
  • Anterior (palmar or volar ) Sensation by Nerve: 1 = median nerve; 2 = dorsal radial sensory nerve; 3 = ulnar nerve; 4 = lateral antebrachial cutaneous nerve; 5 = medial antebrachial cutaneous nerve; 6 = radial dorsal antebrachial cutaneous nerve; 7 = medial brachial cutaneous nerve; 8 = intercostobrachial nerve; 9 = axillary nerve (superior lateral brachial cutaneous nerve.
    Anterior (palmar or volar ) Sensation by Nerve: 1 = median nerve; 2 = dorsal radial sensory nerve; 3 = ulnar nerve; 4 = lateral antebrachial cutaneous nerve; 5 = medial antebrachial cutaneous nerve; 6 = radial dorsal antebrachial cutaneous nerve; 7 = medial brachial cutaneous nerve; 8 = intercostobrachial nerve; 9 = axillary nerve (superior lateral brachial cutaneous nerve.
  • Posterior (Dorsal) Sensation by Nerve: 1 = median nerve; 2 = dorsal radial sensory nerve; 3 = ulnar nerve (dorsal ulnar sensory nerve); 4 = lateral antebrachial cutaneous nerve; 5 = medial antebrachial cutaneous nerve; 6 = posterior brachial cutaneous nerve, inferior lateral cutaneous nerve, posterior antebrachial cutaneous nerve; 7 = medial brachial cutaneous nerve; 8 = intercostobrachial nerve; 9 = axillary nerve (superior lateral brachial cutaneous nerve.
    Posterior (Dorsal) Sensation by Nerve: 1 = median nerve; 2 = dorsal radial sensory nerve; 3 = ulnar nerve (dorsal ulnar sensory nerve); 4 = lateral antebrachial cutaneous nerve; 5 = medial antebrachial cutaneous nerve; 6 = posterior brachial cutaneous nerve, inferior lateral cutaneous nerve, posterior antebrachial cutaneous nerve; 7 = medial brachial cutaneous nerve; 8 = intercostobrachial nerve; 9 = axillary nerve (superior lateral brachial cutaneous nerve.
Symptoms
History of ulnar nerve injury or dysfunction
Poor upper extremity function
Weak pinch and grip
Atrophy of hand muscles
Positive Tests, Exams or Signs
Work-up Options
Treatment Options
Treatment Goals
  • Improve hand and upper extremity function by reestablish intrinsic function, grip and pinch with appropriate ulnar palsy tendon transfers.
Conservative
  • Hand therapy, splinting and various modalities can improve the functional capacity of a patient with a ulnrl nerve palsy but unfortunately cannot completely replace the missing ulnar nerve functions.
  • Hand therapy can improve the active and passive range of motion in the upper extremity prior to tendon transfers.
  • Hand therapy can also improve the strength of the muscles that are not denervated in the upper extremity with a ulnar nerve palsy.
  • A complete ulnar nerve palsy that is not a simple temporary neuropraxia can not be functional corrected without surgery
Operative

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Operative Treatment Options1-3,5,6

  • Tendon transfers should be performed for ulnar nerve palsy when recovery is unlikely, either spontaneously or after nerve repair.
  • There are over forty muscles in the forearm and hand, many of which perform overlapping functions. Therefore, many options are available when selecting a working muscle-tendon unit to replace a non-working muscle-tendon unit in tendon transfer procedures. More than 50 tendon transfer techniques have been described, and the surgeon must therefore decide on which is most appropriate for each patient.  This is especially important given that there is often more than one alternative for each patient.  The surgeon should also be guided by personal experience, training, and previous outcomes.
  • Tendon transfer procedures for ulnar nerve palsy should aim to restore key pinch, improve grip strength, correct clawing, integrate MP and IP joint flexion, and restore fourth and little finger DIP joint flexion in high ulnar nerve palsy cases.
  • Determining the appropriate tendon transfer procedure is contingent on which deformity the surgeon intends to correct, and many of the available surgical options can be performed on either high or low ulnar nerve palsy.
    • Correction of clawing
      • Superficialis transfers
        • Modified Stiles-Bunnell transfer
          • Long finger or ring finger superficialis tendon divided distally in finger and retrieved into the palm
          • One slip of the transferred FDS can be used to tenodese the PIP joint to prevent post-operative hyperextension
          • The ring and/or long finger FDS can either be both used or one can be split into two slips, with each one being passed along the path of the lumbrical, volar to the deep transverse metacarpal ligament, and back into the finger, where it is inserted on the lateral band
          • PIP joint hyperextension can occasionally occur in patients, especially in patients with lax joints
            • Can be prevented by inserting the tendon on the proximal phalanx instead of the lateral band
        • Zancolli lasso transfer
          • Flexor digitorum superficialis (FDS) tendon is passed through the A1 pulley, then sutured back onto itself, which creates a lasso around the A1 pulley creating an MP flexion tenodesis
          • If Bouvier’s test is negative, the surgeon may instead insert the FDS tendon into the lateral band
      • Wrist-level motor transfers
        • In addition to correcting clawing, these procedures also integrate finger flexion and improve grip strength
        • Brand transfer
          • Uses the extensor carpi radialis longus (ECRL) or ECRB to provide both MP joint flexion and IP joint extension
          • ECRL or ECRB is harvested at the wrist, extended with tendon grafts and routed through the carpal tunnel or dorsally across the wrist. After crossing the wrist, the tendons are passed through the interosseous space into the palm.  They are then passed volar to the deep transverse metacarpal ligament and secured distally to the lumbrical tendons and/or lateral bands.
        • Other wrist-level motors that may be used include the FCR and brachioradialis
        • If adhesions develop in the intermetacarpal space during these procedures, the excursion will be severely limited. Thus, the opening should be large enough so the tendon graft can easily pass through this area. The insertion can be into the lateral band, the proximal phalanx, or the A1 or A2 pulley.
    • Correction of power pinch
      • ECRB adductor-plasty
        • The ECRB is detached from its insertion on the base of the index metacarpal and retrieved proximal to the extensor retinacululm
        • From here, a free tendon graft is used as an extension on the end of the ECRB and routed distally between the index and long finger metacarpals and attached to the adductor pollicis insertion of the thumb metacarpal
      • FDS adductor-plasty
        • Alternative to ECRB adductor-plasty
        • FDS of long or fourth finger is harvested proximal to its insertion, routed across palm, and attached to the adductor pollicis insertion of the thumb metacarpal.  The palmar fascia is used as a pulley for this transfer. 
        • A third alternative is a combined MP joint arthrodesis and extensor pollicis brevis to first dorsal interosseous tendon transfer13 as taught by Carroll and described by Omer.14
  • Combined median and ulnar nerve palsy1,5,9
    • Due to the severity of these injuries and the limited motor nerves available for use, standardized tendon transfers are often not possible. Thus, surgical treatment must instead be individualized, and multiple procedures are usually required. Tenodesis and capsulodesis procedures may also be needed to supplement the tendon transfer.
    • Attention to the principles of tendon transfer is particularly important for these injuries to increase the chances of a successful outcome. Surgeons must carefully think out the staging and timing of each of the multiple procedures used and should only perform tendon transfer procedures simultaneously that can be rehabilitated together.
    • Combined low median-ulnar palsy
      • Requires restoration of opposition and key pinch, reintegration of MP and IP joint flexion, and treatment of clawing
      • Available donors for reconstruction: muscle-tendon units innervated by the radial nerve and more proximal muscle-tendon units innervated by the median and ulnar nerve that are uninjured
      • Surgical reconstruction options
        • ECRB or FDS transfer for key pinch
        • EIP opponensplasty or FDS opponensplasty for thumb opposition
        • ECRL or brachioradialis transfer to integrate finger flexion and improve clawing
        • Brand technique
          • Can be used for clawing of all four digits
          • FCR or ECRB tendon is split into 2–4 tails based on the number of fingers being addressed
          • The tails are then extended using free tendon grafts and attached to the radial lateral bands of the long, fourth, and little fingers and the ulnar lateral band of the index finger
    • Combined high median-ulnar palsy
      • Primary reconstruction goals: restoration of key pinch, opposition, and simple grip strength
      • Only muscle-tendon units innervated by the radial nerve are available as donors
      • Surgical reconstruction options
        • ECRB, brachioradialis, EIP, or FDS transfer for restoring key pinch
        • ECRL to FDP transfer for restoring finger flexion and grip strength
        • EIP, EPL, or ECU opponensplasty for restoring thumb opposition
        • PT to ECRB transfer for restoring wrist extension
        • FDS transfer for restoring finger and thumb extension

Nerve Transfers15, 16

  • Nerve transfer for brachial plexus reconstruction are well defined in the literature6; however, their usefulness for reconstructing ulnar nerve lacerations is less well studied.  However, nerve transfer(s) have been gaining in popularity as an alternative to tendon transfers/nerve grafting for patients with severe proximal nerve injuries, but the field is still evolving with new techniques being described as microsurgical techniques improve and more patients experience good outcomes.
  • Proposed Advantages of Nerve Transfer
    • Able to also restore sensory function
    • Multiple muscle groups can be reinnervated with a single nerve transfer
    • Muscle origin/insertions are not disrupted
  • Principles of Nerve Transfer
    • Ideally pick a donor nerve near the motor endplates of the target muscle to minimize time to innervation.  A shorter distance means shorter time  for reinnervation
    • Use expendable or redundant nerve fibers
    • Use donors that have a large number of axons
    • Use donors that already innervate synergistic muscles with the target muscle (helps facilitate re-education)
    • Using donors that match the target is ideal, i.e. motor donors for motor targets, sensory donors for sensory targets
    • Re-innervation after 12-18 months may be impossible, as prolonged denervation will cause muscle cell death and fibrosis.
  • Nerve Transfers for Ulnar Nerve Palsy
    • Goals: Restore intrinsic muscle function and ulnar sensation
    • Transferring the branch of the AIN to the motor branch of the ulnar nerve can restore intrinsic function
    • This nerve transfer does not provide synergistic function and will only provide some improvement to prevent clawing
    • Ring and small finger flexion can be improved by side to side tenodesis of the respective FDP tendons to the index and long FDP tendons
    • Ulnar sensory function can be restored by performing a transfer from the third web space nerves which come from the median nerve

AIN to Deep Motor Branch
For ASSH's Hand-e Surgical Video of AIN to deep motor branch of the ulnar nerve "super charge": ​

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Treatment Photos and Diagrams
Ulnar Nerve Palsy Transfers
  • Patient with chronic clawing after ulnar laceration of wrist repaired years ago.
    Patient with chronic clawing after ulnar laceration of wrist repaired years ago
  • Stiles-Bunnell tendon transfer using FDS IV, with one slip for ring (arrow) and one for little finger. PIP joints pinned temporarily in neutral position.
    Stiles-Bunnell tendon transfer using FDS IV, with one slip for ring (arrow) and one for little finger. PIP joints pinned temporarily in neutral position.
  • Stiles-Bunnell tendon transfer using FDS (2) which will be woven into and sutured to the radial lateral band (1).
    Stiles-Bunnell tendon transfer using FDS (2) which will be woven into and sutured to the radial lateral band (1).
EPB and Thumb MP arthrodesis pinch transfer
  • Incisions for EPB and Thumb MP arthrodesis pinch transfer
    Incisions for EPB and Thumb MP arthrodesis pinch transfer. The dorsal radial sensory nerve should be protect when these incisions are used to expose the deeper structures.
  • The EPB and Thumb MP arthrodesis pinch transfer as taught by Carroll begins with a longitudinal incision over the thumb MP joint. The capsule is opened and the EPB released from its capsular insertion and proximal soft tissue attachments. The cartilage is removed from the head of the metacarpal and proximal phalanx and the collateral ligaments and volar plate released. A standard cone-in-cup arthrodesis is then performed and internally fixed with one or two k-wires. Once the arthrodesis is completed, the
    The EPB and Thumb MP arthrodesis pinch transfer as taught by Carroll begins with a longitudinal incision over the thumb MP joint. The capsule is opened and the EPB released from its capsular insertion and proximal soft tissue attachments. The cartilage is removed from the head of the metacarpal and proximal phalanx and the collateral ligaments and volar plate released. A standard cone-in-cup arthrodesis is then performed and internally fixed with one or two k-wires. Once the arthrodesis is completed, the EPB is identified through a proximal transverse incision just distal to the radial styloid. The EPB is then passed with a clamp through the first dorsal interosseous muscle belly to the dorsal radial aspect of the index metacarpal head. Here the transfer EPB is visualized through a third incision. The EPB is woven through the first dorsal interosseous tendon and sutured with some tension. All incisions are closed and splints applied.
The extensor indicis (EIP) pinch transfer
  • This drawing shows the dorsal incisions for the extensor indicis (EIP) transfer to the thumb abductor tendon.
    This drawing shows the dorsal incisions for the extensor indicis (EIP) transfer to the thumb abductor tendon.
  • This drawing shows the palmar incision for the extensor indicis (EIP) transfer to the thumb abductor tendon.
    This drawing shows the palmar incision for the extensor indicis (EIP) transfer to the thumb abductor tendon.
  • The extensor indicis (EIP) transfer to improve thumb abduction starts with an incision over the index MP joint and the ulnar aspect of the metacarpal neck. The EIP is released from the extensor hood over the base of the index proximal phalanx. The defect at (1) is repaired. The EIP is passed subcutaneously and under the long EDC. Next a clamp is used to pass it through the III-IV metacarpal interspace and into the palm. The tendon and clamp are identified ulnar to the long metacarpal and flexor tendon shea
    The extensor indicis (EIP) transfer to improve thumb abduction starts with an incision over the index MP joint and the ulnar aspect of the metacarpal neck. The EIP is released from the extensor hood over the base of the index proximal phalanx. The defect at (1) is repaired. The EIP is passed subcutaneously and under the long EDC. Next a clamp is used to pass it through the III-IV metacarpal interspace and into the palm. The tendon and clamp are identified ulnar to the long metacarpal and flexor tendon sheath. A small incision exposes the clamp and tendon at the proximal palmar crease. Next, the tendon is passed under (dorsal) to the neurovascular structures and flexor tendons and then along the adductor muscle to the adductor tendon. Here it is exposed through a third incision on the dorsal ulnar aspect of the thumb MP joint. Through this incision the EIP is sutured to the adductor tendon (2). The tension is set with the wrist in neutral and the thumb and index aligned in parallel.
Complications
  • Infection
  • Bleeding
  • Blood vessel or nerve damage
  • Hand stiffness or weakness
  • Tendon rupture
  • Tendon adhesions
  • Transfer weakness
  • Swan neck deformity5,10
Outcomes
  • A review of various tendon transfer procedures to correct clawing in ulnar nerve palsy found that improvements in grip strength were minimal for the Stiles-Bunnell transfer (7% improvement) but modest for the Zancolli lasso transfer (16% improvement). The Stiles-Bunnell transfer was most effective for correcting clawgin in long-standing paralysis.10
  • Another study found that using ECRL or ECRB transfers was more effective for correcting ulnar clawing than FDS transfers
    • In 861 fingers assessed after an average of 2 years after an ECRL or ECRB transfer, 50% rated their hand opening as excellent and 34% reported it as good. Comparatively, in 564 fingers treated with FDS transfers, only 31% reported this function as excellent and 42% as good.11
  • FDS transfer procedures are effective for correcting clawing and integrating finger flexion, but they do not improve grip strength, and may even exacerbate weakening in some patient1
  • Outcomes of combined median and ulnar nerve palsies are generally worse than those of single nerve palsies due to the severity of the associated injuries responsible and lack of donor muscle-tendon units. In combined high median-ulnar nerve palsies, even multiple reconstructive operations often fail to help the hand function much better than a prosthesis.1
Key Educational Points
  • Patient and surgeon must be aware that tendon transfers can improve function but do not return the hand to normal.  In particular, grip strength and pinch strength will usually remain decreased.
  • The power of a muscle is related to his cross-sectional area. The transferred muscle will most likely lose some power. Therefore, only muscles rated 4+ or better should be considered acceptable donor motors.9
  • A muscles work capacity is calculated as the product of the muscle power times its amplitude9
  • There is still controversy regarding the optimal timing for tendon transfers. Most experts agree it’s necessary to wait until sufficient time has elapsed to determine that further nerve recovery will not occur, but some new research suggests that immediate transfers should be performed in certain situations (e.g. a gap of >4 cm between nerve ends, when the nerve is in a deep wound of scar tissue, and with major tissue loss).8
  • If sensation is unable to be restored, a tendon transfer may also fail to restore movement1
References
  1. Sammer, DM and Chung, KC. Tendon transfers: Part II. Transfers for ulnar nerve palsy and median nerve palsy. Plast Reconstr Surg 2009;124(3):212e-21e.     PMID: 19730287
  2. Seiler, JG, 3rd, Desai, MJ and Payne, SH. Tendon transfers for radial, median, and ulnar nerve palsy. J Am Acad Orthop Surg 2013;21(11):675-84. PMID: 24187037
  3. Loewenstein, SN and Adkinson, JM. Tendon Transfers for Peripheral Nerve Palsies. Clin Plast Surg 2019;46(3):307-315. PMID: 31103075
  4. Lane, R and Nallamothu, SV.Claw Hand. In: StatPearls.Treasure Island (FL): 2020. PMID 29939558
  5. Carl, DJ and Habusta, SF.Hand Tendon Transfers. In: StatPearls.Treasure Island (FL): 2020. PMID: 29083655
  6. Ratner, JA, Peljovich, A and Kozin, SH. Update on tendon transfers for peripheral nerve injuries. J Hand Surg Am 2010;35(8):1371-81. PMID: 20684937
  7. Sammer, DM and Chung, KC. Tendon transfers: part I. Principles of transfer and transfers for radial nerve palsy.Plast Reconstr Surg 2009;123(5):169e-177e. PMID: 19407608
  8. Bumbasirevic, M, Palibrk, T, Lesic, A, et al. Radial nerve palsy. EFORT Open Rev 2016;1(8):286-294. PMID: 28461960
  9. Leddy, JP and Leddy, TP. (1997). Tendon Transfers in the Hand and Forearm, in Dee R et al (Eds.) Principles of Orthopaedic Practice. New York: McGraw-Hill, 1152-1158.
  10. Ozkan, T, Ozer, K and Gulgonen, A. Three tendon transfer methods in reconstruction of ulnar nerve palsy. J Hand Surg Am 2003;28(1):35-43. PMID: 12563635
  11. Brand, PW. Tendon grafting: illustrated by a new operation for intrinsic paralysis of the fingers. J Bone Joint Surg 1961;43:444-53.
  12. Wilbur, D and Hammert, WC. Principles of Tendon Transfer. Hand Clin 2016;32(3):283-9. PMID: 27387072
  13. DeAbreau, LB. Early restoration of pinch grip after ulnar nerve repair and tendon transfer. J Hand Surg (B) 1989;14B:309-314.
  14. Omer, GE. Tendon transfers for reconstruction of the forearm and hand following peripheral nerve injuries. In: Management of Nerve Problems, eds Omer, GW & Spinner, M, W.B. Saunders Co., Philadelphia, London, Toronto, 1980.
  15. Chan, KM, Olson, JL, Morhart, M, et al. Outcomes of nerve transfer versus nerve graft in ulnar nerve laceration. Can J Neurol Sci 2012;39(2):242- PMID: 22343162
  16. Weber RV, Mackinnon SE. Nerve transfers in the upper extremity. J Hand Surg Am. 2004; 4(3): 200-213.
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