Background: This study was designed to observe the effect of preserving the spinal accessory nerve (SAN) during neck dissection (ND) and adjuvant radiotherapy (ART) after ND on shoulder function.
Methods: Fifty-seven patients with head and neck cancer who had undergone primary tumor resection and various types of NDs were enrolled in this prospective study. Postoperative shoulder joint range of motion was evaluated by goniometry, and muscle strength was measured manually. SAN function was evaluated with electromyography (EMG) with respect to percentage of denervation and presence of neurogenic involvement. Patients were grouped by treatment as follows: radical ND (RND) versus modified radical ND (MRND)/selective ND (SND) and ART versus no ART.
Results: Shoulder joint range of motion and shoulder muscle strength were significantly better in the MRND/SND group than in the RND group. However, EMG findings were similar in the RND and MRND/SND groups. When all patients who underwent ND, RND, or MRND/SND were compared with the control group, statistically significant changes in shoulder joint range of motion and shoulder muscle strength were found. Also, denervation and neurogenic involvement of the SAN were significantly higher after all NDs than in the control group. ART did not affect range of motion of the shoulder joint, shoulder muscle strength, or the degree of denervation and neurogenic involvement in any of the ND groups.
Conclusions: ART does not have a negative effect on shoulder function after ND. SAN is always functionally impaired even if we preserve it macroscopically during ND.