BACKGROUND: The purpose of this study was to show the investigated impact of supraomohyoidal neck dissection and modified radical neck dissection, both combined with radiotherapy, on cervical range of motion (CROM), mouth opening, swallowing, lymphedema, and shoulder function.

METHODS: One hundred eight patients who had neck dissections and 98 patients who had non-neck dissections were evaluated in a prospective, nonselective, longitudinal cohort study by a physiotherapist and a speech-language pathologist (SLP) before the start of radiotherapy and up to 12 months after treatment.

RESULTS: The incidence of shoulder disability after neck dissection was 18%. Supraomohyoidal neck dissection had no significant effect on the evaluated parameters at any time point. Modified radical neck dissection significantly reduced CROM and mouth opening 2 months after treatment, but after 12 months only cervical rotation was still significantly reduced.

CONCLUSION: In patients treated with external beam radiation (EBRT), modified radical neck dissection induced additional morbidity regarding CROM but not regarding mouth opening, swallowing, and lymphedema 1 year after treatment. Both modified radical neck dissection and supraomohyoidal neck dissection induced shoulder disability.