Reinnervation of thenar muscle after repair of total brachial plexus avulsion injury with contralateral C7 root transfer: Report of five cases

Abstract

In this report, we present the findings of reinnervation of the thenar muscle in five patients who underwent the contralateral C7 nerve root transfers for repair of total brachial plexus root avulsions. Five (2 children and 3 adults) of 32 patients who received two-staged procedures of the contralateral C7 nerve root transfers to the median nerves showed reinnervation of thenar muscle were evaluated. The patients also received other procedures including the intercostal nerve transfer to the musculocutaneous nerve, the spinal accessory nerve to the suprascapular nerve, and the ipsilateral phrenic nerve to the musculocutaneous nerve before the contralateral C7 nerve root transfers. The patients were followed up from 24 to 118 months after surgery. Varied degrees of functional restorations were achieved after different procedures. The strength of abductor pollicis brevis (APB) muscle with Grade M2 was found in four patients. The incomplete interference pattern in the APB muscle was detected by electromyogram (EMG) in two patients, and the minority motor unit potential (MUP) was detected in other two patients. The strength of APB muscle was found with Grade M1 in one patient with EMG showing MUP. The findings from our series show reinnervation of thenar muscles after repair of the median nerve with the contralateral C7 nerve root transfer, which provides evidence for further investigation of reconstruction of the brachial plexus root avulsion injury with this procedure.