Quantifying Neck Disability After Neck Dissection in HNSCC —A Prospective Study of Patient‐Reported and Objective Functional Outcomes

Background Neck dissection, a cornerstone of head and neck squamous cell carcinoma (HNSCC) treatment, is associated with significant postoperative neck disability. This study prospectively evaluates the trajectory of patient‐reported and objective functional outcomes to quantify disability and identify key predictors. Methods A prospective cohort of 178 patients undergoing neck dissection for HNSCC was assessed preoperatively and at 3, 6, and 12 months postoperatively. The primary outcome was the change in the Neck Disability Index (NDI). Secondary outcomes included neck pain (Visual Analog Scale, VAS), patient‐specific function (Patient‐Specific Functional Scale, PSFS), cervical range of motion (CROM), manual muscle testing (MMT), and spinal accessory nerve (SAN) function. Results At 12 months, functional outcomes failed to return to preoperative baselines. A significant proportion of patients had severe neck disability (NDI > 25, 22.7%) or poor objective neck mobility (CROM < 70% normative, 26.7%). Radical neck dissection (RND vs. MRND/SND: OR = 2.10, 95% CI: 1.02–4.32), dissection involving levels IV/V (OR = 2.45, 95% CI: 1.11–5.39), and administration of chemotherapy (OR = 2.18, 95% CI: 1.02–4.66) were independent predictors of severe disability. The upper trapezius was the most affected muscle, with SAN function remaining impaired in 42% of patients at 12 months. Strong correlations were observed between subjective disability and objective measures like CROM ( r = −0.72, p < 0.001) and trapezius strength ( r = −0.65, p < 0.001). Conclusion Neck dissection results in persistent disability strongly linked to surgical extent and chemotherapy. The concordance between patient‐reported and objective measures underscores the need for integrated assessment and the development of tailored, multidisciplinary rehabilitation to mitigate long‐term morbidity.