title: Ultrasonography for intraoperative determination of tumor thickness and resection margin in tongue carcinomas.
abstract: OBJECTIVE
  Exact estimation of tumor thickness and the status of the resection margin in tongue carcinoma are important prognostic factors for local recurrence, subclinical nodal metastasis, and survival. This study aims to evaluate the accuracy of intraoral ultrasonography-guided measurement of tumor thickness and define an adequate intraoperative resection margin in squamous cell carcinomas of the tongue.
  
  
  METHODS
  In this prospective study, 13 patients with presurgical, biopsy-proven, clinical T1N0 or T2N0 tongue squamous cell carcinomas who underwent a partial glossectomy were examined preoperatively with ultrasonography to assess tumor thickness under general anesthesia. Nine cases underwent resection by a conventional method, whereas we introduced elastic needles with a metal core to mark a deep surgical margin of 10 mm from the deepest tumor invasion front under ultrasonographic monitoring as a new technique in the remaining 4 cases. Each resected specimen was immediately immersed in gelatin solution while maintaining its original shape and orientation and was placed under refrigeration to solidify. Ultrasonographic observations of the gelatin-embedded specimens were performed from the superior surface of the gelatin block.
  
  
  RESULTS
  Very fine ultrasonographic images of the resected specimen could be easily obtained without any special skills, and surgical clearance could be verified intraoperatively. The ultrasonographic tumor thickness measurements corresponded well with those of histologic sections, with a consistency ratio of 91.4% to 98.2% (Pearson correlation coefficient = 0.981, P < .05).
  
  
  CONCLUSIONS
  Intraoperative ultrasonography is a reliable method to objectively evaluate tumor thickness and surgical margin clearance.
authors.affiliation: Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu, Japan. m-kodama@kyu-dent.ac.jp
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kodama
authors.forename: Amit
authors.initials: A
authors.lastname: Khanal
authors.forename: Manabu
authors.initials: M
authors.lastname: Habu
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Iwanaga
authors.forename: Izumi
authors.initials: I
authors.lastname: Yoshioka
authors.forename: Tatsurou
authors.initials: T
authors.lastname: Tanaka
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tominaga
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D005260:Female; D005927:Glossectomy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007430:Intraoperative Care; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D016610:Tissue Embedding; D014062:Tongue Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D047368:Tumor Burden; D014463:Ultrasonography