Poster Presentation NZ Association of Plastic Surgeons & NZ Society for Surgery of the Hand

Ultrasound visualization of the spinal accessory nerve in patients with lymphadenopathy (1476)

Ali Sarfarazi 1 , Ali S Mirjalili 2 , Mohammad J Gharib 3
  1. Plastic and reconstructive surgery, Middlemore hospital, Auckland
  2. Department of Anatomy, University of Auckland , Auckland
  3. Auckland City hospital, Auckland

Background. Injury to the spinal accessory nerve (SAN) during surgical procedures is a significant source of morbidity. Injury is often due to the highly variable course of the SAN in the posterior triangle and therefore surface anatomy inherently unreliable. We hypothesized that ultrasound can be used to accurately map the course of the spinal accessory nerve in patients with lymphadenopathy and should be utilized preoperatively to minimize iatrogenic injury.

Materials and Methods. Nine subjects with lymphadenopathy (six bilaterally) were analyzed using ultrasound. The caliber, course and distribution of the SAN in the posterior triangle were recorded along with the number and size of adjacent lymph nodes.

Results. The nerve was visualized running across the posterior triangle with either a tortuous (82%) or straight course (18%). It exited the posterior border of sternocleidomastoid at a mean distance of 5.69cm (3.07-8.25) below the mastoid process and 0.95cm (0.29-1.9) above the great auricular point and penetrated the anterior border of the trapezius 6.34cm (3.3-9.5) above the clavicle. The spinal accessory nerve always ran superficial to the lymph nodes and there were on average 6.36 (1-18) lymph nodes adjacent to the nerve.

Conclusions. The spinal accessory nerve can be consistently and reliably detected by ultrasound in patients with lymphadenopathy. Due to the extremely variable course of the spinal accessory nerve and unreliable surface anatomy, ultrasound has an important role to play in preoperative mapping of the nerve to reduce the risk of iatrogenic injury.