INVESTIGATION OF A COAXIAL BIPOLAR NERVE STIMULATOR FOR INTRAOPERATIVE MOTOR-NERVE MONITORING

Intraoperative cranial motor nerve monitoring has improved the preservation of cranial nerve function during cerebellopontine angle and skull base surgery. Further improvements are needed to provide greater selectivity and sensitivity during intraoperative motor nerve stimulation. Use of bipolar stimulator probes has been recommended by previous investigators, The authors hypothesized that a coaxial bipolar stimulator design might provide important advantages over existing designs. This study compared the results of bipolar and monopolar stimulation using a coaxial stimulator probe in a rat model and during neurotologic procedures. The coaxial bipolar probe was superior in selectivity, there by permitting useful multichannel monitoring. The coaxial design may also offer advantages over previous bipolar stimulator designs.