Electrophysiologic assessment is performed by somatosensory-evoked potentials evaluation (SSEP). Under ketamine anesthesia, the stimulating electrodes were placed subcutaneously into the dorsum of the foot and the Achilles tendon, ground electrode was inserted subcutaneously to the gluteal area. Then, approxiametely 2 cm sagittal incision is made on the scalp, the cranium is exposed by subperiosteal dissection. Two burr holes are created in the parietal bones of the skull and recording electrodes are placed to the epidural plane over the somatosensory cortex region. After 300 trials, the averages are obtained. SSEP measurements were done and positive (P) and negative (N) potentials of the waveform morphology are obtained. The P1 (first positive wave) and N2 (the second negative wave) are the most robust and consistent potentials, therefore they are used for comparison of sensory recovery [21]. Wave amplitudes are also measured for assessment of axonal regeneration. Latencies and amplitude values are evaluated as a percentage from the unoperated side (P1 %, N2 %, Amp %) to eliminate the anesthesia factor.