Tongue somatosensory-evoked potentials in microvascular decompression treated trigeminal neuralgia.

Somatosensory-evoked potentials of the tongue (tSSEP) provide useful information about trigeminal-afferent pathway. The aim of this study was to evaluate tSSEP in trigeminal neuralgia (TN) treatment with microvascular decompression. Two patients with trigeminal neuralgia refractory to conservative treatment underwent microvascular decompression of the trigeminal nerve. tSSEP was performed a month prior to surgery and in the month after the surgery in both patients. Pain frequency and tSSEP were analyzed before and after surgery. In both patients, a complete resolution of pain occurred. In patient 1, tSSEP latencies became shorter than before surgery and wave N1 appeared. The intensity of stimulation necessary to reach the threshold was 4 mA before the surgery and 1 mA after the surgery. A complete recovery of tSSEP after the operation was achieved in patient 2. The results of present study demonstrate potential value of tSSEP in pre-surgery evaluation and post-surgery follow-up of TN patients.