Increasing evidence suggests that 1-hour electrical nerve stimulation during surgery improves nerve regeneration and functional recovery. However, it remains unknown if this approach has beneficial effects on the outcomes of our recently developed nerve-muscle-endplate band grafting-native motor zone (NMEG-NMZ) technique for muscle reinnervation.Methods
In this study, NMEG-NMZ transplantation was performed in a rat model. The right sternomastoid muscle was experimentally denervated and immediately reinnervated by implanting a NMEG harvested from the ipsilateral sternohyoid (SH) muscle into the NMZ of the target muscle. Before implantation of the NMEG, the SH nerve branch innervating the NMEG was subjected to intraoperative 1-hour continuous electrical stimulation (20 Hz). Three months after surgery, the degree of functional recovery was evaluated with muscle force measurement and the extent of nerve regeneration and endplate reinnervation was examined using histological and immunohistochemical methods.Results
A combination of NMEG-NMZ with electrical nerve stimulation resulted in a greater degree of functional recovery than the NMEG-NMZ alone. The mean muscle force of the treated muscles was 90% of the contralateral control. The muscle mass was recovered up to 90% of the control. The mean number and percentage of area of the regenerated axons in the treated muscles was computed to be 81 and 84% of the control muscles, respectively. On average, 83% of the denervated endplates in the treated muscles were reinnervated by regenerated axons.Conclusion
Intraoperative brief nerve stimulation promotes nerve regeneration, endplate reinnervation, and functional recovery of the muscles reinnervated with NMEG-NMZ technique.