Current Concept of Selective Nek Dissection

Abstract

It has long been known that the most important prognostic factor of squamous cell carcinoma of the head and neck is the presence of cervical lymph node metastasis. When neck metastases are not managed properly, this will result a decrease the patient’s chance of survival. Radical neck dissection has been introduced in the beginning of 1900’s as the surgical procedure to remove cervical lymph nodes systematically in an effort to address metastases and been used widely since then. But radical neck dissection was associated with significant morbidity and especially patients with clinically negative neck were suffering from this unnecessary morbidity. Almost 60 years after introduction of radical neck dissection, Suarez (Ferlito & Rinaldo, 2004) presented modified radical neck dissection (often termed as functional neck dissection). Though, the morbidity associated with neck dissection had been reduced by modified radical neck dissection, efforts to further reduce the morbidity continued and in 1985, Byers (Byers, 1985) reported removal of the cervical lymph node levels which are at the greatest risk for metastasis in patients with clinically negative neck, a surgical procedure which will later be called “selective neck dissection” (Robbins et al, 1991). The rationale behind selective neck dissection is removal of certain lymph node groups, which are at risk for occult metastasis, while preserving the functional structures of the neck and the lymph node groups that are not likely to contain metastasis, in an effort to reduce the risk of complications and morbidity associated with neck dissection. The current and widely used classification of neck dissections has been introduced by a group of authors from the American Head and Neck Society and American Academy of Otolaryngology-Head and Neck Surgery in 2002 (Robbins, 2002). According to this classification, SND refers to selective neck dissection and the removed lymph node groups are depicted in brackets. For example selective neck dissection involving levels II to IV is recorded as SND (II-IV). The committee also recommended the extent of dissection for each anatomic sub-site. For oral cavity cancer, the recommended procedure was SND (I-III), which was formerly called as supraomohyoid neck dissection. It was noted that level IV might be involved in patients with oral tongue cancer and SND (I-IV), which was formerly called as extended supraomohyoid neck dissection, may be warranted in these patients. The recommended procedure for oropharyngeal, hypopharyngeal and laryngeal cancers was SND (II-IV), which was formerly called lateral neck dissection. The committee noted that level IIB involvement was rare in laryngeal and hypopharyngeal cancers, thus SND (IIA,III,IV) would be sufficient, however removal of level IIB was recommended for