Intraoperative Spinal Accessory Nerve Monitoring During Neck Dissection Surgery as a Predictor for Shoulder Dysfunction.

Shoulder dysfunction is one of the most common complications seen in patients who have undergone neck dissection surgery. The prevalence of shoulder dysfunction increases depending on the type and extent of neck dissection surgery. We aim to study the relationship between changes in intraoperative neuromonitoring (IONM) threshold during SAN stimulation, ultrasonographic measurement of muscle size and shear wave elastography with shoulder dysfunction. This is a prospective study. All patients who have undergone neck dissection in our centre have been recruited. Analysis of demographic data, IONM threshold during exposure and pre-closure, shoulder function score, neck disability index score (NDII) and ultrasonographic parameters pre-op and during follow up was done. The cohort was divided into patients who suffered from shoulder dysfunction post op (Group A) and patients with normal shoulder function post op (Group B). Statistical significance were seen in IONM threshold during SAN stimulation and Constant shoulder score for 6 months follow up in Group A. IONM threshold difference during exposure and pre-closure could effectively prognosticate shoulder dysfunction post op. A return of shoulder function could be seen in patients who suffered from shoulder dysfunction if early physiotherapy could be commenced.