Impact of Neck Dissection on Scapular Muscle Function: A Case-Controlled Electromyographic Study

Abstract Objective To assess the dynamic activity of scapular muscles in patients with accessory nerve dysfunction after neck dissection surgery, compared with both their unaffected side and with age- and sex-matched controls. Design A case-control investigation. Setting Physiotherapy department of a hospital. Participants Two groups of 10 participants were recruited. One group consisted of neck dissection patients with demonstrated clinical signs of accessory nerve injury. The second group was composed of matched healthy individuals. Interventions Surface electromyographic activity of the upper trapezius, middle trapezius, rhomboid major, and serratus anterior muscles was compared dynamically during scapular strengthening exercises. Main Outcome Measures Electromyographic activity comparisons were made between the neck dissection affected side, the neck dissection unaffected side, and the matched healthy control side. Raw data and data expressed as a percentage of maximal voluntary isometric contraction were compared. Results The neck dissection affected side demonstrated significantly less upper trapezius and middle trapezius muscle activity compared with the neck dissection unaffected side and matched control group. The neck dissection unaffected side had significantly less upper trapezius muscle activity than the matched control group. Conclusions Trapezius muscle activity is significantly reduced in accessory nerve shoulder dysfunction as a result of neck dissection, both in the affected and unaffected sides. This needs to be considered in the rehabilitation of this patient group.