Convergent end‐to‐end neurorrhaphy: An alternative technique for dual innervation of the gastrocnemius muscle in rats

Abstract

Introduction: Muscle contraction generated by electrical impulses simultaneously originating from two different neural sources may be an interesting treatment alternative for long term facial palsy. An experimental model was designed to compare single and dual innervation of the gastrocnemius muscle (GM) in rats.Methods: Fifty adult Wistar rats underwent transection of their right peroneal nerve and were divided into five groups (n = 10): control (C), tibial nerve section (TS), tibial nerve primary end-toend neurorrhaphy (PEE), tibial nerve primary repair associated with end-to-side peroneal-to-tibial nerve transfer (PRES), and tibial nerve repair by convergent end-to-end (CEE) neurorrhaphy between the proximal stumps of the tibial and peroneal nerves to the distal stump of the tibial nerve. The outcomes were assessed 12 weeks after the experiment by walking track, electromyography, GM mass index, and histomorphometric analysis of the distal tibial nerve. Results:The functional recovery of the PRES (−33.77 ± 24.13) and CEE (−42.15 ± 31.14) groups was greater (P < 0.003) than the PEE group (−80.26 ± 17.20). The CEE group (18.35 ± 7.84) showed greater amplitude (P = 0.006) than the PEE group (8.2 ± 4.64). There was no difference in the muscle mass index among the reinnervation groups (P > 0.705). Histologic analysis revealed greater (P < 0.002) axonal density in the CEE group (126.70 ± 15.01) compared to PEE (99.70 ± 12.82) and PRES (92.00 ± 19.17) groups. Conclusions:The dual innervation techniques showed earlier and greater functional recovery of the GM than did the single innervation technique. The CEE group showed a 40% higher number of regenerated axons in the distal tibial nerve stump.

Experimental study on the repair of peripheral nerve injuries via simultaneously coapting the proximal and distal ends of peripheral nerves to the side of nearby intact nerves

“…The number of myelinated common peroneal nerve fibers per unit area in the foster group was more than that in the open group and closer to that in the normal group. Previous studies have confirmed ( 19 , 20 ) the importance of repairing proximal nerves in the treatment of peripheral nerve injuries. The reason may be that more nerves are available for attracting peripheral repair materials, and donor nerve epineuria act as a bridge for axon regeneration.…”

Novel Method of Dual-innervated Free Gracilis Muscle Transfer for Facial Reanimation: A Case Series

“…9,39,40 The stronger excursion with the additional input from the masseteric nerve is well supported by various basic science animal studies that show stronger nerve input and faster muscle recovery with dual innervation, as opposed to single innervation. [20][21][22]26 Time to reinnervation was shown to be important for muscle force. 41 We postulate that the masseteric nerve provides additional input to the muscle and prevents atrophy of the gracilis after transfer.…”

“…The concept of dual innervation is supported in the basic science animal literature. [20][21][22] In many of the dual innervation techniques, the arrangement of nerves allows the branch to masseter to dominate the nerve input to the gracilis muscle. 13,[15][16][17]19,23,24 We report a novel modification to the existing nerve coaptation configurations.…”