Supercharge Nerve Transfer to Enhance Motor Recovery: A Laboratory Study

Abstract

Purpose To investigate the ability of a supercharge end-to-side (SETS) nerve transfer to augment the effect of regenerating native axons in an incomplete rodent sciatic nerve injury model. Methods Fifty-four Lewis rats were randomized to 3 groups. The first group was an incomplete recovery model (IRM) of the tibial nerve complemented with a SETS transfer from the peroneal nerve (SETS-IRM). The IRM consisted of tibial nerve transection and immediate repair using a 10mm fresh tibial isograft to provide some, but incomplete, nerve recovery. The 2 control groups were IRM alone and SETS alone. Nerve histomorphometry, electron microscopy, retrograde labeling, and muscle force testing were performed. Results Histomorphometry of the distal tibial nerve showed significantly increased myelinated axonal counts in the SETS-IRM group compared to the IRM and SETS groups at 5 and 8 weeks. Retrograde labeling at 8 weeks confirmed increased motoneuron counts in the SETS-IRM group. Functional recovery at 8 weeks showed a significant increase in muscle specific force in the SETS-IRM group compared to the IRM group. Conclusions A SETS transfer enhanced recovery from an incomplete nerve injury as determined by histomorphometry, motoneuron labeling within the spinal cord, and muscle force measurements. Clinical Relevance A SETS distal nerve transfer may be useful in nerve injuries with incomplete regeneration such as proximal Sunderland II or III degree injuries, where long regeneration distance yields prolonged time to muscle reinnervation and suboptimal functional recovery.

Double innervated free functional muscle transfer for facial reanimation

“…Recently Farber and Mackinnon [30] demonstrated the positive effect of a supercharged nerve transfer in an experimental study based on peroneal nerve transfers in rats, which demonstrated improvements resulting from the double axonal charge. This technique was then later used in the treatment of patients with brachial plexus injuries with similar improvements in outcome.…”

Motor and Sensory Nerve Transfers in the Forearm and Hand

“…Brown and Mackinnon demonstrated that neurolysis of the ulnar nerve can be performed up to 14 cm proximal to the radial styloid. 4 The reverse end-to-side or "supercharge" nerve transfer 40,41 can also increase intrinsic function and allow the ulnar nerve to recover spontaneously also. 42 In 1997, Wang and Zhu demonstrated transfer of the anterior interosseous nerve to the ulnar motor branch or to the thenar branch of the median nerve in cadavers and clinically but did not differentiate the outcomes.…”

Nerve Transfers in the Treatment of Peripheral Nerve Injuries

“…It provides a fast muscle re-innervation with preservation of the muscle bulk until the axons of the damaged nerve regenerate and reach their own endplates [66]. This avoids muscle atrophy while the injured nerve axons regenerate [71]. It has been used successfully in the case of anterior interosseous nerve (AIN) to motor fascicle of the UN transfer [52].…”

“…The clinical outcome is very satisfactory [29,62,152]. Another possibility is a reverse end-to-side transfer, avoiding atrophy of the UN innervated hand muscles while awaiting for the native UN motor axons to regenerate [70,71,154]. It is very effective [29].…”