2b or not 2b? Shoulder function after level 2b neck dissection: A double-blind randomized controlled clinical trial.

BACKGROUND: Selective neck dissection (SND) is a mainstay of head and neck cancer treatment. A common sequela is shoulder syndrome from spinal accessory nerve (SAN) trauma. Extensive dissection in neck levels 2 and 5 leads to SAN dysfunction. However, it is not known whether limited level 2 dissection reduces SAN injury. The purpose of this double-blind randomized controlled trial was to determine whether omitting level 2b dissection would improve shoulder-related quality of life and function. METHODS: Patients with head and neck cancers undergoing surgery were randomized 1:1 to SND without level 2b dissection (group 1) or with it (group 2) on their dominant-hand side. Patients, caregivers, and assessors were blinded. The primary outcome was the change in the Neck Dissection Impairment Index (NDII) score after 6 months. An a priori calculation of the minimally important clinical difference in the NDII score was determined to establish a sample size of 15 patients per group (power = 0.8). Secondary outcomes included shoulder strength and range of motion (ROM) and SAN nerve conduction. The trial was registered at ClinicalTrials.gov (NCT00765791). RESULTS: Forty patients were enrolled, and 30 were included (15 per group). Six months after the surgery, group 2 demonstrated a significant median decrease in the NDII from the baseline (30 points) and in comparison with group 1, whose NDII dropped 17.5 points (P = .02). Shoulder ROM and SAN conduction demonstrated significant declines in group 2 (P