Nerve Transfer for Restoring Upper Limb Function in Traumatic Cervical Spinal Cord Injury

Abstract

Introduction: Cervical spinal cord injury (CSCI) is a devastating consequence of trauma that leads to disabling loss of upper limb function. Restoration of any upper limb function can improve quality of life, reduce long-term care needs, and is highly rated by affected individuals. Historically, the International Classification of Surgery of the Hand in Tetraplegia (ICHST) has guided the use of tendon transfers in CSCI but there is now renewed interest in the role of nerve transfer. Selective nerve fascicle transfer offers opportunities for greater functional gain with restoration of prehensile grip and maintenance of donor muscle function. We present an evidence-based surgical strategy for restoration of upper limb function using nerve transfer in CSCI. Objectives: Derivation of evidence-based surgical algorithm for restoration of upper limb function in CSCI. Methods: A nonsystematic review of all studies reporting nerve transfer in CSCI available through PubMed was performed. For each level of spinal cord injury, a reconstructive algorithm was constructed considering available donors. The following hierarchy of movement was prioritized: elbow extension, wrist extension, finger flexion, finger extension, and intrinsic function. Results: The reconstructive algorithm derived is summarized below.

>C5—Limited donors available. Suggest lateral branch of accessory nerve transfer to long thoracic nerve or phrenic nerve (in cases of phrenic nerve palsy). Achievable outcomes: respiratory independence for ventilator or cough assist.

C5*^†—Suggest: (1) Axillary nerve fascicle to teres minor transfer to medial or long head of triceps fascicles. (2) Proximal supinator nerve transfer to nerve to extensor carpi radialis brevis (ECRB) fascicles. (3) Finger extensor tenodesis. (4) Nerve to brachialis transfer to fascicles to anterior interosseous nerve (AIN) and pronator teres. Achievable outcomes: active elbow and wrist extension, passive finger extension, active pronation, and finger flexion.

C6*^†—Suggest: (1) Axillary nerve fascicle to teres minor transfer to medial or long head of triceps fascicles. (2) Nerve branches to supinator transfer to ECRB. (3) Finger extensor tenodesis. (4) Nerve to brachialis transfer to fascicles to AIN and pronator teres. Achievable outcomes: active elbow extension, stronger active wrist and passive finger extension, active pronation, and finger flexion.

C7*^†—Suggest: (1) Nerve to brachialis transfer to fascicles to AIN and pronator teres. (2) posterior interosseous nerve (PIN) branches to abductor pollicis longus (APL), extensor pollicis brevis (EPB) and extensor indicis proprius (EIP) transfer to deep branch ulnar nerve fascicles. Achievable outcomes: active pronation, finger flexion, and intrinsics.

C8*—Suggest: (1) AIN branch to pronator quadratus transfer to deep branch ulnar nerve fascicles. (2) PIN branches to APL, EPB and EIP transfer to deep branch median nerve fascicles. Achievable outcomes: active intrinsics.

Conclusion: Nerve transfer for CSCI is an emerging area of upper limb surgery that demonstrates very significant promise. A bespoke surgical strategy tailored to each patient’s level of CSCI and individual needs that is undertaken early during the rehabilitative course will revolutionize functional outcomes for this deserving patient group.

*Brachioradialis to flexor pollicis longus (FPL) tendon transfer as necessary.

^†House intrinsic tenodesis and/or carpometacarpal joint (CMCJ) arthrodesis as necessary.