Impairment of neck and shoulder function after neck dissection: a comparative study of goniometry, EMG and paper pencil tool in a randomized controlled trial of level IIb preserving verses conventional neck dissection.

Background: Surgical management of oral cancer poses significant challenges due to the proximity of critical nerves, like spinal accessory, which increases the risk of inadvertent damage or neuropraxia during surgery.

Methods: A randomized controlled trial enrolled 32 patients with histologically confirmed oral cavity carcinoma and clinically and radiologically negative cervical neck nodes. Patients were assigned to either level IIb-preserving or conventional selective neck dissection. Shoulder function was evaluated using goniometry, electromyography (EMG), and the Neck Dissection Impairment Index (NDII). Outcomes from these three assessment methods were compared.

Results: Both groups exhibited impaired spinal accessory nerve function. In the IIb-preserving group, EMG detected impairment in 50% of patients, compared to 95% in the control group. Statistically significant differences were observed between groups across all three assessment methods. However, EMG and goniometry indicated functional recovery at 6 and 12 months, whereas NDII scores remained significantly different at 12 months, despite full nerve recovery observed on EMG and goniometry.

Conclusions: The study demonstrates agreement between shoulder function measurements (goniometry and EMG) but discordance with NDII. This discrepancy may arise from the distinct constructs used by NDII to assess neck dissection impairment, highlighting potential limitations in its sensitivity to functional recovery.