Description of the
surgical procedure
The neck dissection method was selected in accordance with the
preoperative examination, primary tumour extent and regional lymph node
metastasis. Patients with N0–N1 underwent ipsilateral Ⅱ–Ⅳ selective
neck dissection, patients with N2 underwent ipsilateral Ⅱ–Ⅴ neck
dissection, and patients with N3 underwent ipsilateral Ⅰ–Ⅴ +
contralateral Ⅱ–Ⅳ neck dissections. If the tumour crosses the midline,
bilateral neck dissection is performed; level VI and retropharyngeal
lymph node dissections were performed for patients with T3–T4 and N2b
or above.