Early and mid-term electrophysiological study of the contralateral C7 nerve transfer using the medial antebrachial cutaneous nerve as a bridge to the deep branch of ulnar nerve

Objective To explore the early and mid-term electrophysiological recovery of the contralateral C7 nerve transfer using the medial antebrachial cutaneous nerve to bridge the deep branch of ulnar nerve. Methods From July 2016 to June 2017, 40 patients with total brachial plexus injury were treated, of which 20 cases were treated with the repair of median nerve and deep branch of ulnar nerve through the bridge of pedicled ulnar nerve and medial cutaneous nerve of forearm (experimental group), and 20 cases were treated with the repair of median nerve through the bridge of pedicled ulnar nerve (control group). The early electrophysiological recovery of abductor pollicis brevis, abductor digiti minimis and dorsal interosseous muscles in the affected side was evaluated by electromyography (EMG) examination. Results The follow-up time was 19 to 30 months with an average of 24.9 months. In the control group, motor unit potential (MUP) could be recorded in abductor pollicis brevis in 4 cases, a small amount of recruitment phase, and compound muscle action potential (CMAP) could be recorded in abductor pollicis brevis in 1 case. MUP could not be recorded in abductor digiti minimi and dorsal interosseous muscles in all the patients. In the experimental group, a small amount of MUP could be recorded in abductor pollicis brevis in 5 cases, CAMP could be recorded in abductor pollicis brevis in 2 cases. A small amount of MUP could be recorded in the abductor digiti minimi in 5 cases, in the dorsal interosseous muscle in 2 cases, and CAMP could be recorded in abductor digiti minimi and dorsal interosseous muscles in 1 case. There was significant difference between the two groups in the recovery of MUP of abductor digiti minimi (P 0.05). Conclusion The contralateral C7 nerve transfer by bridging medial antebrachial cutaneous nerve to deep branch of ulnar nerve was confirmed electrophysiologically that the function of intrinsic hand muscles achieved early recovery in the patients with total brachial plexus injury without affecting the recovery of median nerve. Key words: Brachial plexus; Nerve transfer; Contralateral C7 nerve root; Medial antebrachial cutaneous nerve; Deep branch of ulnar nerve