Neurorrhaphy after loss of a nerve segment: comparison of epineurial suture under tension versus multiple nerve grafts.

Epineural neurorrhaphy under tension and interfascicular grafting, two methods of bridging gaps associated with loss of a nerve segment, were compared. After resection of a 2 cm length of both ulnar nerves in cats, one nerve was sutured under tension using an epineurial technique, and the other was repaired using multiple interfascicular sural nerve grafts. Six months later return of nerve function was evaluated. Subjective evaluation included ambulation, sensation, and intrinsic function. Objective measurements included muscle efficiency, maximum strength, muscle weights, and total axon counts. No statistical difference was observed between these two techniques. Histochemically, there was marked fiber type grouping of the reinnervated muscles for both types of repairs. Histologically, perineurial fibrosis and axonal disorganization were equal for both techniques, but significantly greater suture granuloma formation occurred in the nerve repaired under tension. Individual grafts retained their identity and remained distinct grossly and microscopically.