Sensory Restoration in Cortical Level After a Contralateral C7 Nerve Transfer to an Injured Arm in Rats

BACKGROUND: The restoration of sensory and motor function in brachial plexus root avulsion patients is a difficult challenge. The central nervous system plays an important role in sensory recovery after peripheral nerve injury and repair. OBJECTIVE: To investigate the sensory restoration process after surgery at the cortical level in rodent models with a contralateral C7 nerve transfer. METHODS: Thirty-five male Sprague-Dawley rats were used in this experiment, and both behavioral tests and somatosensory evoked potentials were used to investigate the sensory function recovery of the injured forepaws and the cortical reorganization in the rats postoperatively. RESULTS: The results demonstrated a dynamic change in the ipsilateral somatosensory cortex, both in the shape and location, where overlapping sensory cortical representations of the healthy and injured forepaws were observed consistently. Behavioral tests show that the sensation first occurred only in the healthy forepaw and later in both when stimulating the injured one, which suggested a tendency of the sensation function to recover in the injured forepaws of the rats as time progressed. CONCLUSION: The cortical reorganization occurred only in the ipsilateral hemisphere, which is different from the motor cortex reorganization using the same model as that described in a previous study. This reorganization pattern offers an interpretation of the unique sensory recovery process after the transfer of the C7 nerve to the contralateral median nerve, but also provides the basis for further sensory restoration in clinical practice.