Spinal Accessory Nerve Monitoring and Clinical Outcome Results of Nerve-Sparing Neck Dissections.

ABSTRACT

OBJECTIVE: To investigate the role of intraoperative spinal accessory nerve monitoring in predicting postoperative shoulder function in spinal accessory nerve-sparing neck dissections. STUDY DESIGN: Prospective, double-blind clinical trial. SETTING: Academic, tertiary care center. SUBJECTS AND METHODS: This study was performed on 20 neck sites of 17 consecutive patients who had neck dissections sparing the spinal accessory nerve. Threshold increment ≥0.25 mA and amplitude decrement ≥72% were classified as significant intraoperative neuromonitoring changes while lesser differences were classified as insignificant intraoperative neuromonitoring changes. All patients had intraoperative neuromonitoring recordings when the spinal accessory nerve was first identified and at the end of surgery. Postoperative shoulder function was evaluated neurophysiologically with electromyography and clinically with Constant-Murley Score; daily activity restrictions were evaluated with Activity Restriction Scale. RESULTS: Clinical assessment of shoulder functions at postoperative first and second months showed statistically significant deteriorations when compared with preoperative values (P < .05). The shoulder function deterioration was statistically significantly less for patients with insignificant intraoperative neuromonitoring changes than patients with significant intraoperative neuromonitoring changes (P < .05). Daily activity restriction deteriorations were present in both groups at first postoperative month (P < .05). While they persisted in the group with significant intraoperative neuromonitoring changes during the second postoperative month (P < .05), there was continuing recovery in the insignificant intraoperative neuromonitoring change group and statistical significance disappeared (P > .05). CONCLUSION: Our results support the predictive value of spinal accessory nerve intraoperative neuromonitoring for determining shoulder function deterioration and activity restriction scores.