Background: To investigate the accessory nerve function in lateral selective neck dissections (LSND) performed in laryngeal squamous cell carcinoma patients without dissection of level IIB. Methods: Fifteen LSND were performed in 11 N0 laryngeal carcinoma patients with preservation of level IIB. Distal latencies, compound muscle action potentials (CMAP), and electromyography findings were investigated before surgery, during the 3rd postoperative week, and 3 months thereafter to compare the effects of the procedure on the accessory nerve. Results: Distal latencies and CMAP values were significantly lower in the early and late postoperative periods when compared with preoperative values. In 8 patients, there was no motor unit potential (MUP) in the early postoperative period. However, in the late postoperative period, there was no MUP loss. Conclusions: Only temporary functional deterioration of the accessory nerve was seen in patients in whom LSND was performed with undissected level IIB. Copyright (c) 2006 S. Karger AG, Basel.