Neurophysiological studies of peripheral nerve functions after neural regeneration following nerve suture in man

Eleven patients, of which the majority had sustained total transection of the median nerve at the wrist, were investigated at least 5 years after epineural nerve suture. Electrophysiological examinations included conventional electromyography and electroneurography, as well as percutaneous microelectrode exploration of the sutured nerves proximal to the site of injury. In all cases the functional neural recovery was incomplete as evaluated by electrophysiological techniques. The most satisfactory clinical and electrophysiological recovery was observed in the youngest patients with the shortest delay from injury to nerve suture. Aside from reduced conduction velocity single regenerated myelinated fibres had qualitatively normal response characteristics and receptive fields as revealed by recording with microelectrodes. Multi-unit recordings however disclosed abnormal fascicular receptive fields which consisted of two to four separate skin patches in reinnervated skin. This misdirection of regenerated nerve fibres may account for faulty sensory localization of light tactile stimuli in the area of reinnervation. The clinical implications of the appearance of this phenomenon during the process of reinnervation are discussed.