Reliability of disposable intraoperative facial nerve stimulators

Facial nerve injury is one major morbidity of surgery performed along the course of this nerve. Surgeons frequently employ stimulators to identify and protect the nerve. Both disposable devices as well as larger, reusable stimulators are available. Despite their common use, relatively little documentation exists regarding the safety and reliability of these devices. We tested the electrical output of the four disposable, single-use motor nerve stimulators that are marketed in the United States. We found that each produced consistent stimulus output over time. One stimulator slightly exceeded the manufacturer's listed output while three devices produced significantly less voltage and current than specified by the manufacturer.