71. Intraoperative blink reflex monitoring during microvascular decompression for trigeminal neuralgia

Microvascular decompression surgery (MVD) is an established technique for refractory trigeminal neuralgia. In order to reduce the risk of 5°, 7° and 8° cranial nerve lesions, intraoperative monitoring is recommended. To evaluate intraoperative BR modification during MVD surgery. Considering the reflex arc, BR could be useful to monitor sensory part of trigeminal nerve, facial nerve and brainstem function during MVD. We evaluated BR intraoperative modifications in all patients who underwent MVD surgery for trigeminal neuralgia from 2013 to 2016. All the patients underwent surgery with monitoring of BAEPs, EMG free run, BR and direct nerves stimulation. BR was recorded in 14/18 patients. In 12/14 R1 amplitude was stable; these patients didn’t report postoperative facial or trigeminal nerve lesions. In 2/14 we observed intraoperative decrease of R1 amplitude. In one patient, we recorded B and C train at EMG free run; after the operation, he experienced a transient facial palsy. In the other patient, we didn’t record spontaneous pathological EMG activity in facial muscles and we recorded stable amplitude responses after direct nerves stimulation. After the operation, he reported hemifacial hypoesthesia. BR can be an integrative monitoring technique during MVD surgery.