Intraoperative Neuromonitoring in Peripheral Nerve Stimulation

Peripheral nerve stimulation (PNS) is defined as the application of electric stimulation to the peripheral nervous system and to a specific nerve. For the most part, the goal of PNS has been treatment of pain. Later, PNS use expanded to indications other than pain including epilepsy and depression, which involves stimulation of the vagus nerve, sleep apnea with stimulation of the hypoglossal nerve, respiratory insufficiency, involving phrenic nerve stimulation, and many others. The overarching peripheral neuromodulation approach involves three modalities: conventional PNS, which implies direct placement of stimulating electrode leads over the affected peripheral nerve(s); percutaneous PNS, which implies insertion of stimulating electrode leads near the target nerve with appropriate guidance; and peripheral nerve field stimulation, which requires placement of electrode leads to stimulate smaller nerves and nerve endings in the affected target area. Monitoring peripheral nerves during surgery through electrophysiological methods is a highly valuable option, offering crucial real-time information to the surgical team. While preoperative testing provides helpful data for decision-making, intraoperative neurophysiological monitoring (IONM) fills in gaps that cannot be addressed by preoperative studies. IONM assesses the nervous system during surgery to prevent potential damage to critical neurological structures. It serves the next main purposes: detecting and minimizing iatrogenic injuries, mapping nervous structures to identify the target nerve, and assessing the functionality of the nerve. In this article we review currently available information about the utilization of IONM during PNS procedures.