Classification of neck dissections: an evolving system.

The authors review the evolving development of various types of neck dissections, and the resultant classification systems. The standard radical neck dissection, introduced at the turn of the 20th century, became the uniformly accepted treatment of cervical metastatic disease through the 1960s. The functional or modified radical neck dissection was developed in the 1950s and 1960s. This procedure became accepted treatment for suitable tumors by the 1970s. The concept of selective neck dissection, removal of only the node levels likely to be involved with tumor, gained acceptance by the late 1980s as definitive elective, and eventually, therapeutic neck dissection for suitable cases. In response to the increasing variations of neck dissection procedures, a number of classification systems were proposed and subsequently established. The system most often employed was published in 1991 by the American Head and Neck Society and the American Academy of Otolaryngology-Head and Neck Surgery. The system was revised in 2002 and 2008. These systems employ the American Joint Committee on Cancer staging system and traditionally established node levels. The neck dissections are grouped into four broad categories of radical neck dissection, modified radical neck dissection, selective neck dissection (this group is subclassified according to which node levels are removed) and extended neck dissection. Recently, the Japan Neck Dissection Study Group presented a new system for classification of neck dissections based on a system of letters and symbols. The system permits a comprehensive "shorthand" method of precise designation of the neck dissection procedure, but has the disadvantage of departing radically from previously employed systems by utilizing an entirely new terminology and designation of lymph node groups. This factor portends a lack of acceptance by surgeons long accustomed to conventional terminology. The abbreviated and tabular method of classifying neck dissections, however, is advantageous, and would be useful if integrated into the currently used terminology.