Spinal Accessory Nerve Monitoring in Head and Neck Surgery

The spinal accessory nerve (SAN) is a vital structure encountered in many surgeries of the head and neck. The anatomy of the SAN is complex, and identification intraoperatively is key in preventing injury. Compromise of the SAN leads to an array of findings known as postoperative shoulder syndrome, which has a significant impact on patients’ quality of life and contributes to a significant amount of malpractice litigations. Surgeries where the SAN is most at risk include neck dissection, surgery of the posterior triangle such as lymph node biopsies, and lateral skull base surgery. While the frequency of postoperative shoulder syndrome has been mitigated by the trend toward SAN-sparing surgeries in head and neck cancer, it remains a worrisome complication. Intraoperative nerve monitoring is widely used in various head and neck surgeries and has more recently been applied to the SAN. Literature to support the use is variable and relatively limited.