A preliminary analysis of reconstructed nerve function using targeted muscle reinnervation in a rat model

The previous studies have demonstrated that by transferring residual nerves to alternative muscle sites, the targeted muscle reinnervation (TMR) technique could provide a rich source of motor control information to improve myoelectrical control of a multifunctional prosthesis in patients with above-elbow amputations. However, it seems to lack the detailed investigations about the recovery progress of the targeted muscle function after reinnervation surgery, which may be important for further improving the TMR surgery and prosthesis control. In this study, a rat TMR model was developed by transferred the medial nerve of the rats into their pectoralis major muscle and was used to investigate the electrophysiological function of the targeted muscle. An implanted electrode was used to record the intramuscular myoelectric signals from the targeted muscle in the TMR rats and the histomorphometric analysis was performed to visualize the reinnervation of the medial nerve within the pectoralis major muscle. Our results of this pilot study showed that the myoelectric signals from the reinnervated muscle could be clearly recorded about one week post TMR and the newly growing fibers in the targeted muscle could be for the first time observed.