Restoration of Intrinsic Hand Function By Superficial Radial Nerve: An Anatomical Study

Abstract

Abstract Background:Contralateral seventh cervical(cC7) nerve root transfer is one of the most important techniques for treating total brachial plexus avulsion injury. The traditional cC7 uses the whole ulnar nerve as a graft, which sacrifices the restorative potential of the ulnar nerve. Objective: This innovative cadaveric study aims to evaluate the possibility and feasibility of modified cC7 that preserve the motor branch of the ulnar nerve(MBUN), after cC7, using recovered superficial radial nerve(SRN) to repair. Methods: Ten adult cadavers provided by the Anatomy, Histology, and Embryology Department of Fudan University, China were dissected to evaluate the feasibility of this technique. In this study, only the dorsal and superficial branches of the ulnar nerve and SRN were harvested to connect the cC7 nerve and the recipient nerves. Both the median nerve and MBUN were the recipient nerves. To evaluate the feasibility, the SRN, as well as the motor and sensory branches of the ulnar nerve were dissected. The distances from the reverse point of SRN to wrist flexion crease, as well as to the coaptation point of SRN and MBUN were measured. The MBUN was dissected from distal to proximal and the maximum length was measured. The diameter of nerve branches and the number of axons were evaluated. Results:This modified approach was technically feasible in all limbs. The distances from the reverse point of SRN to wrist flexion crease was 8.20±1.72cm, and that to the coaptation point was 6.63±1.67cm. The maximum length of the MBUN was 7.44±1.16cm. The mean diameters of axons of the MBUN and SRN distal lateral and medial branches were 1.85±0.41mm、1.99±0.45mm and 1.57±0.37mm, respectively. The corresponding mean numbers of axons were 1401±140 and 742 ±73、712 ±59, respectively. Conclusion: The SRN could be transferred to the MBUN without a nerve graft. The possible advantage of this modification was that the potential of MBUN was preserved.