OBJECTIVE: Neck dissection results in a high probability of postoperative shoulder functional impairment, even when the spinal accessory nerve is preserved . Therefore, surgeons must inform patients about the expected functional and qualitative recovery of shoulder function after surgery .
METHODS: The present study included a prospective cohort of 66 patients (85 neck dissection sides) who underwent neck dissection between December 2015 and July 2017 at a single institution . The active shoulder abduction angles of the affected side and the patient-reported shoulder-specific quality-of-life recovery score of the Western Ontario Rotator Cuff (WORC) questionnaire were examined at 1 , 3 , 6 , 9, and 12 months postoperatively . Additionally, the association between these outcomes and risk factors for shoulder impairment were investigated .
RESULTS: The average active shoulder abduction angles were significantly improved at 3 and 6 months postoperatively compared with 1 month postoperatively (96.5 ± 4.3° at 1 month versus 110.1 ± 4.7° at 3 months, p = 0.035, and versus 142.0 ± 4.6° at 6 months, p <0.0001). The proportion of patients who were unable to abduct their shoulders by 150° or more was significantly lower at 6 months postoperatively (41.5 %) compared with 1 month postoperatively (82.4%, p <0.0001). The WORC score significantly improved from 60.4 ± 2.4% at 1 month postoperatively to 67.9 ± 2.6% at 6 months postoperatively (p = 0.036). Multivariate analysis revealed that postoperative radiotherapy was a significant risk factor for shoulder impairment at 3 and 6 months postoperatively (p = 0.003 and p = 0.027, respectively), and that level V dissection and head and neck irradiation were significant risk factors for a worse shoulder outcome at 6 and 9 months postoperatively (respective p values for level V dissection and head and neck irradiation were p = 0.049 and p = 0.030 at 6 months postoperatively, and p = 0.016 and p = 0.013 at 9 months postoperatively).
CONCLUSION: Satisfactory functional and qualitative recovery of shoulder function was achieved at 6 months after neck dissection . Postoperative radiotherapy was a predictor of poor shoulder function in the early postoperative period; both level V dissection and head and neck irradiation were predictors of poor shoulder function at 6 and 9 months after neck dissection.