Comparison of Skin Mechanoreceptor Function and Sensation After Nerve Repair (P6.258)

Objective: Recovery of sensation after nerve repair is incomplete. Recovery of tactile sensation and mechanoreceptor function were analyzed and compared following repair with a collagen nerve conduit or by suture of median or ulnar nerve lesions in the forearm. Background: Previous studies have detailed recovery of sensory modalities after nerve repair, but it is less well known how this recovery relates to nerve and sensory receptor function. Furthermore, the influence of different types of repair is unknown. Design/ Methods: 20 patients (15 males), aged 20-64 years with complete lesions of the median (13) or ulnar (8) nerves were randomly assigned to repair with a collagen conduit (11 nerves) or suture (10 nerves), and the patients were followed for 2 years. Sensory nerve action potentials (SNAPs) evoked by electrical and tactile stimulation at digit 3 or 5, respectively, were recorded by near-nerve needles. Sensory function was studied using the sensory domain of Rosen-score. Results: There were no clinical or electrophysiological differences between repair procedures. There was a significant correlation (P<0.001) between recovery of the sensory quotient and the area of the SNAP. Touch threshold recovered to 84±3[percnt] (mean±SEM) and the tactile SNAP area recovered to 84±16[percnt] of controls at 2 years after repair. Conclusions: Mechanoreceptor and sensory function recovered incompletely after nerve repair with a nerve conduit or suture but was similar in both the repair procedures. There was a good recovery of touch threshold but less recovery of discriminative touch suggesting that this is dependent on interaction between peripheral and central mechanisms. Study Supported by: The study was sponsored by Integra LifeSciences and by the Danish Medical Research Council and the Lundbeck Foundation.