A Novel Approach to Identifying the Spinal Accessory Nerve in Surgical Neck Dissection.

Intraoperative identification of the spinal accessory nerve (SAN) is key in reducing nerve injury. This study aims to explore the surgical anatomy of the SAN and 2 landmarks for its identification-the sternocleidomastoid branch of the occipital artery (SBOA) and superior sternocleidomastoid tendon (SST)-to propose a novel method of identifying the SAN during surgical neck dissections. Twelve cadavers underwent bilateral level II-V neck dissection identifying the SAN, SBOA, and SST. Variation was documented and distance between landmarks and the SAN measured. The most common arrangement had the SST most superficially followed by the SBOA and then the SAN. The SAN was 3.63 ± 4.02 mm from the artery and 2.31 ± 1.72 mm from the tendon. A triangle-bordered by the tendon laterally, artery medially, and digastric muscle superiorly-contained the SAN in 95.8% of cases. This relationship translated into a reliable technique to identify the SAN intraoperatively, which has been used successfully in practice.