Decreased muscle strength and scapular muscle endurance associated with shoulder function after neck dissection

BACKGROUND: Shoulder disability is a common problem following neck dissection. Even if nerve structures are preserved, this may occur after the surgery. OBJECTIVE: The primary aim was to research changes in rotator cuff and scapular muscles strength, and scapular muscle endurance after neck dissection in patients with head and neck cancer. The secondary aim was to investigate the relationship between these changes and postoperative shoulder function. METHODS: This cross-sectional and prospective follow-up study included 14 patients who underwent neck dissection (9 unilateral and 5 bilateral). Evaluations were performed preoperatively and at 3 months postoperatively. Muscle strength measurements, including trapezius, serratus anterior, and rotator cuff muscles, were obtained using a handheld dynamometer. The scapular muscle endurance test was used for muscle endurance assessment. Postoperative shoulder function was evaluated using Constant-Murley shoulder score. RESULTS: A decrease in muscle strength and the scapular muscle endurance test was found at 3 months postoperatively, except for the subscapularis muscle strength ( p < 0.05). There were moderate to strong correlations between Constant-Murley shoulder score and percentage changes in muscle strength and the scapular muscle endurance test, except for the upper trapezius muscle strength (p < 0.05). CONCLUSIONS: Muscle strength and scapular muscle endurance may reduce following neck dissection. These reductions are associated with postoperative shoulder function. Thus, muscle strength and endurance training may be beneficial for early postoperative rehabilitation in patients with head and neck cancer.