Lack of Topographical Specificity in Sensory Nerve Regeneration through Muscle Grafts in Rats

Regenerating sensory axons of each receptor class make new connections with similar denervated receptors. This study investigates to what extent these axons return to their original receptive field. The lateral cutaneous nerves of the thigh in rats were divided and allowed to regenerate across a 6 mm. gap interposed with frozen and thawed muscle graft towards their original distal nerve stump and a "foreign" sensory nerve, the saphenous nerve. 16 weeks later, myelinated axon counts of 26 pairs of distal nerves showed no preferential growth towards the original receptive field. Lack of topographic specificity during sensory nerve regeneration may explain the faulty localisation of sensation after nerve repair in clinical practice. Following sensory nerve regeneration, the somatosensory cortex receives accurate afferent information but from disparate skin sites; this probably alters the relationship of overlapping sensory fields and may be the cause of distorted pattern recognition.