Extent of lymphadenectomy achieved by various modifications of neck dissection: a pathologic analysis

Quantify the extent of lymphadenectomy achieved by the various modifications of neck dissection based on microscopic pathologic analysis.

Retrospective review of neck specimens of patients who underwent neck dissection for head and neck malignancies at our institution over a 5-year period.

Charts and pathology report findings on patients who underwent neck dissection were reviewed. Patients who received preoperative chemotherapy or radiation therapy to the neck were excluded. The number of lymph nodes documented by pathologic microscopic examination for each specimen was recorded.

There were 164 neck specimens on 135 patients (29 patient had simultaneous bilateral neck dissection). Those were divided into four groups based on the nonlymphatic structures preserved. There were 58 radical neck dissections (radical neck dissections) (group 1), 50 modified radical neck dissections sparing the eleventh cranial nerve (group 2), 15 modified radical neck dissections sparing the eleventh cranial nerve and internal jugular vein (group 3), and 33 modified radical neck dissections sparing the eleventh cranial nerve, internal jugular vein, and sternocleidomastoid muscle (group 4). The remaining 8 had other modifications of radical neck dissection. The mean number of lymph nodes found per specimen was 34 in group 1, 27 in group 2, 31 in group 3, and 22 in group 4. We performed one-way between-group analysis of variance (ANOVA). Pair-wise comparisons of means were carried out subsequent to ANOVA utilizing the Fisher Exact Test. Group 4 was significantly different from all other groups. Additionally, group 2 significantly differed from group 1.

The extent of lymphadenectomy achieved by neck dissection decreases as the number of nonlymphatic structures preserved in the neck increases. The impact of this finding on the pathologic staging or prognosis needs further analysis.