INTRAOPERATIVE TRIGEMINAL SOMATOSENSORY EVOKED POTENTIAL CHANGES DURING PERCUTANEOUS BALLOON COMPRESSION FOR TRIGEMINAL NEURALGIA

Percutaneous balloon compression (PBC) is an established surgical treatment for trigeminal neuralgia (TN); however, intraoperative objective markers predicting clinical outcome are limited. Trigeminal somatosensory evoked potentials (TSEPs) have not previously been systematically investigated during PBC. This study aimed to evaluate intraoperative changes in TSEP responses during PBC and to assess their relationship with postoperative pain relief.
Nine patients with TN undergoing PBC were included. Stimulation electrodes were placed on the pathological side at the V2 (one electrode) and V3 (two electrodes) branches, and on the healthy side at either V2 or V3. Sequential electrical stimulation was delivered at 0.8 Hz using an alternating pulse waveform (6–14 mA). TSEP recordings consisted of 100 averaged stimuli over 120 seconds. Recording electrodes were positioned at C5 or C6 contralateral to the pathological side, with reference at Fz. Measurements were obtained before, during, and after balloon inflation.
Marked changes in TSEP responses were observed in all nine patients following PBC. In seven patients, TSEP changes were consistent with postoperative clinical outcomes based on verbal pain relief reports. In two patients, TSEP changes were not concordant with clinical outcomes.
This study represents the first systematic intraoperative assessment of TSEPs during PBC for TN. The findings suggest that TSEP monitoring may provide an objective neurophysiological correlate of clinical pain relief, although interindividual variability exists. Larger cohorts are required to further validate the predictive value of TSEP changes during PBC.