Neck stiffness and its correlation with dysphagia after radiotherapy in head and neck cancer

Dysphagia is one of the most significant adverse effects after radiotherapy (RT) for advanced head and neck cancer (HNC). We hypothesized that neck stiffness may impair laryngeal elevation (LE) in HNC patients and contribute to post-RT dysphagia. We evaluated the association between cervical stiffness and swallowing dysfunction after RT for HNC.

Ultrasound and swallowing function tests were conducted before and 6 months after RT for HNC. Stiffness of the sternocleidomastoid muscle (SM) was measured via shear wave elastography (SWE). To assess swallowing function comprehensively, videofluoroscopic swallowing studies were performed; based on these data, we calculated the Penetration-Aspiration Scale (PAS) score and quantified hyoid bone displacement and LE delay time.

Of 29 patients, 8 showed post-RT dysphagia. Compared to prophylactic irradiation, a significant increase in neck stiffness was observed in the radical irradiation group (p = 0.018). Multivariable logistic regression analysis indicated that greater reductions in laryngeal elevation distance (LED) were significantly associated with post-RT dysphagia (OR: 0.67, 95 % CI: 0.47-1.10, p = 0.035).

SWE demonstrated a significant increase in neck stiffness following radiotherapy. Moreover, a greater reduction in LED was significantly associated with post-RT dysphagia, suggesting that impaired LE function may contribute to its development.