著者

小村 健

出版者

Japanese Society of Oral and Maxillofacial Surgeons

雑誌

日本口腔外科学会雑誌 (ISSN:00215163)

巻号頁・発行日

vol.41, no.7, pp.593-610, 1995-07-20

被引用文献数

16 4

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The parapharyngeal space is frequently invaded by head and neck cancer throughdirect extension, lymph node metastasis, and neural spread.<BR>"Parapharyngeal dissection" is a method for en bloc resection of theparapharyngealspace.<BR>To clarify the incidence, pattern, and risk factors of parapharyngeal involvement, 75 pa-tients (Stage II: 8, Stage lII: 22, Stage N: 45) who underwent parapharyngeal dissection inconjunction with ablation of the primary tumor and radical neck dissection were studiedclinicopathologically. In addition, the clinical usefulness of parapharyngeal dissection wasevaluated.<BR>The results were as follows:<BR>1. Tumor involvement of the parapharyngeal space was histologically confirmed in 46 pa-tients (61.3%). The primary sites of their tumors were the oral cavity in 27 patients (61.3%), the oropharynx in 9 (60.0%), the major salivary glands in 7 (50.0%), and othersites in 3 (100%).<BR>2. The histologic patterns of the parapharyngeal involvement were direct extension of theprimary tumor in 24 patients, nodal involvement in 8, neural spread in 3, direct exten-sion combined with nodal metastasis in 10, and nodal involvement combined with neural spread in 1.<BR>3. The risk of direct extension was significantly related to the T category, clinical stage, growth pattern, depth of invasion, and lymphatic invasion of the primary tumor.<BR>4. There were six routes of direct extension of the tumor into the parapharyngeal space: anteromedial inferior, anteromedial superior, medial central, anterolateral, postero-lateral, and inferior.<BR>5. Nodal spread was histologically observed in the parapharyngeal nodes, retropharyngeal nodes, and the extended nodes of Kiittner.<BR>6. The risk of nodal involvement was significantly related to the clinical stage of the tumor.<BR>7. Neural spread occurred via the lingual and hypoglossal nerves, and the risk of spread wasrelated to perineural invasion by the primary tumor.<BR>8. Based on X-ray CT scans perfomed preoperatively in 69 patients, direct extension was cor-rectl ydiagnosd in 73.9%, nodal involvement in 98.6%, and neural spread in 0 %.<BR>9. The 5-year locoregional control rate was 82.0% in this series, and 77.4% in patients withhistogically positive parapharyngeal involvement. The cause-specific 5-year survivalrate was 66.1% in this series, and 56.9% in patients with histologically provenparapharyngeal involvement. These results suggested that parapharyngeal dissection wasery useful in the management of patients with parapharyngeal involvement.