ReviewSelective neck dissection: A review of the evidence
Introduction
Cervical lymphadenectomy has played an important role in the management of upper aerodigestive tract carcinomas for over a century. The proper application of neck dissection procedures has remained a matter of debate, as modifications to the classical procedure have been devised which result in less postoperative morbidity. Bocca et al.1 demonstrated the oncologic soundness of procedures in which the jugular vein, sternocleidomastoid muscle, and accessory nerve are spared during the dissection.
More recently, selective procedures, in which nodal areas deemed not at risk are left undissected, have been introduced and applied widely. The selective procedures were developed in order to control regional metastasis while reducing the morbidity of radical neck dissection. The basis for description of selective neck dissection procedures is the classification system of lymph node levels published by the American Head and Neck Society.2 Level I includes the submental and submandibular nodes, levels II–IV include the upper, middle, and lower jugular nodes respectively, and level V represents the posterior triangle nodes. Levels and sublevels are depicted in Figure 1. The spinal accessory nerve crosses level II, as depicted in the figure, dividing it into level IIa anteroinferiorly and the smaller level IIb posterosuperiorly.
The aim of this review is to describe the evidence available regarding the application of selective neck dissection procedures in two specific settings: primary treatment in the clinically node-positive neck, and treatment of persistent neck disease after primary radiotherapy.
Section snippets
Morbidity of neck dissection
It is beyond the scope of this review to comprehensively discuss postoperative morbidity of selective and comprehensive neck dissection. The most significant morbidities accrue from postoperative dysfunction of the spinal accessory nerve and resultant trapezius muscle denervation. Cappiello et al.3 (level 4) performed a study which included electrophysiological testing comparing patients whose selective dissections included level V with those whose did not. Posterior triangle dissection was
Histopathologic studies of metastasis
The oncologic basis for selective neck dissection comes from analysis of histopathological findings in comprehensive neck dissection specimens. The underlying principle is that the pattern of neck metastasis from upper aerodigestive tract carcinomas is predictable based on the location of the primary lesion. Shah et al.10 (level 4) provided evidence with a review of 1081 previously untreated patients with squamous cell carcinoma of the upper aerodigestive tract, all of whom underwent
Selective neck dissection for primary treatment of the N+ neck
Given this data on efficacy of leaving levels IIb and V undissected in patients with oral carcinoma, many studies have reported on outcomes after selective neck dissection, with particular attention to regional recurrence rates. Selective neck dissection is frequently used in the absence of clinical disease, and studies such as that from Kerrebijn et al.24 (level 4) compared neck recurrence rates in patients without neck disease with those with occult neck disease. In that retrospective study
Selective neck dissection for salvage of neck persistence/early recurrence
Management of regional disease persistence or recurrence after radiotherapy or initial observation is also a subject of debate. Histopathologic studies have shown that pathologic staging of recurrent disease is frequently higher than clinical staging,38 a fact which highlights the difficulty in clinically assessing this group of patients. However, examination of the patterns of failure provides the basis for determining the extent of surgery required for salvage. For example, Davidson et al.13
Conclusions
This review has discussed the current state of knowledge about management of clinically evident neck metastasis from oral carcinoma. The studies we have compiled provide information which may guide clinical decision-making. Metastasis from oral carcinoma, when present, will occur in the expected cervical lymph node levels in almost 80% of patients. Level V harbors pathologically positive nodes in 5% or fewer of clinically positive necks in patients with oral carcinoma, and level IIb in 10–18%;
Conflict of interest statement
None declared.
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