Assessment of nerve graft donor sites used for reconstruction of traumatic digital nerve defects

Several donor nerve graft sites commonly are used when repairing segmental defects in sensory nerves distal to the wrist. The cross-sectional area and number of fascicles of donor nerves and specific digital nerve segments were investigated to provide guidelines for selection of nerve graft harvest sites according to defects encountered. Nerve segments were harvested from 10 fresh cadavers (20 upper extremities). Five sites of nerve graft were harvested: lateral and medial antebrachial cutaneous nerves (LABCN, MABCN), posterior and anterior interosseous nerves (PIN, AIN), and sural nerves. Four sites of typical segmental nerve defects were harvested in a zone protocol: common digital nerve (zone 4), proper digital nerve (zone 3), digital nerve distal to main dorsal branch at the metacarpophalangeal joint (zone 2), and digital nerve distal to trifurcation at fingertip (zone 1). Sural nerve is the most anatomically similar nerve graft for defects in zone 4 by cross-sectional area and number of fascicles. Lateral antebrachial cutaneous nerve is most appropriate for zone 2 and 3 injuries by both criteria. Fingertip grafts for zone 1 injuries displayed cross-sectional area similarity to PIN, AIN, and MABCN. With regard to number of fascicles, zone 1 digital nerves are most similar to LABCN donors.