Transfer of the Dorsal Cutaneous Branch of the Ulnar Nerve for Restoration of Median Nerve Sensation: A Cadaveric Study.

The use of dorsal cutaneous branch of the ulnar nerve (DCBUN) transfer for median nerve (MN) sensory restoration has not been evaluated anatomically and histologically in humans. The purpose of this study was to evaluate the feasibility of DCBUN to MN transfer for sensory restoration with respect to nerve branch pattern, length, and fascicle count match.Using seven fresh frozen cadaveric upper limb specimens, the DCBUN and its branch patterns, lengths, and sizes were recorded. The MN was exposed within the carpal tunnel and dissected distally to identify the common digital nerves (CDN). Simulated nerve transfer was performed with palmar coaptation of the DCBUN branches with the CDNs. Histological analysis of each nerve branch was performed. The seven specimens had a mean of 3.57 branches (range 2-4) off the DCBUN. The longest branch innervated the dorsal 4th web space, on average reaching 7.6 cm distal to the wrist crease. Transferring the DCBUN branches palmarly did not substantially change their maximum distance distal to the wrist crease. The MN CDNs and DCBUN branches had mean cross-sectional areas of 6.37 and 1.99 mm2 , respectively, and mean fascicle counts of 10.4 and 4.05, respectively. The DCBUN provides 2-4 branches suitable for tension-free end-to-end transfer to the MN CDNs. The individual size of the DCBUN branch is smaller than CDN; however, combining two or more branches of the DCBUN would overcome the fascicle and size mismatch to reconstruct the 1st web space CDN for critical sensory restoration. Clin. Anat., 2018. © 2018 Wiley Periodicals, Inc.