Anatomy of the superficial radial nerve and its target nerves for targeted muscle reinnervation: an anatomical cadaver study

Abstract

Background: Targeted muscle reinnervation (TMR) is a surgical procedure for treating symptomatic neuroma, in which the neuroma is removed and the proximal nerve stump is coapted to a donor motor branch innervating a nearby muscle. This study aimed to identify optimal motor targets for TMR of the Superficial Radial Nerve (SRN).

Methods: Seven cadaveric upper limbs were dissected to describe the course of the SRN in the forearm and motor nerve supply - number, length, diameter, and entry points in muscle of motor branches - for potential recipient muscles.

Results: The radial nerve provided three (3/6), two (2/6) or one (1/6) motor branches to the brachioradialis (BR) muscle, entering the muscle 21.7±17.9 to 10.8±15 mm proximal to the lateral epicondyle. One (1/7), two (3/7), three (2/7) or four (1/7) motor branches innervated the extensor carpi radialis longus (ERCL) muscle, with entry points 13.9±16.2 to 26.3±14.9 mm distal from the lateral epicondyle. In all specimens the posterior interosseous nerve gave off one motor branch to the extensor carpi radialis brevis (ECRB), which divided in two or three secondary branches. The distal anterior interosseus nerve (AIN) was assessed as potential recipient for TMR coaptation and had a freely transferable length of 56.4±12.7 mm.

Conclusions: When considering TMR for neuromas of the SRN in the distal third of the forearm and hand, the distal AIN is a suitable donor target. For neuromas of the SRN in the proximal two thirds of the forearm, the motor branches to the ERCL, ERCB, and BR are potential donor targets.