The Usefulness of Intraoperative Transoral Ultrasound Examination for Head and Neck Surgery

Abstract

Recently, the treatment for early head and neck cancer trends toward a transoral surgery. However, it is difficult to determine the indication for transoral surgery or to evaluate the depth of tumor invasion. Ultrasound (US) examination has some advantages that it can evaluate the tumor in real time and in particular. In this study, we used ultrasonography with small transducer in transoral surgery, and performed intraoral evaluation of tumor thickness. The subjects were patients with oropharyngeal or hypopharyngeal cancer who underwent intraoperative transoral US examination at our department form April 2016 to March 2017. We used Hitachi ARIETTA 70 ultrasound system with laparoscopic US transducer L43K (Hitachi Aloka Medical, Ltd. Tokyo, Japan). We aimed to verify assessable thickness of primary site by transoral US examination and if the tumor was resected with negative deep margin. Furthermore we compared the tumor thickness measured by US and pathological tumor thickness. In total, 10 patients (oropharyngeal cancer: 4, hypopharyngeal cancer: 4, oral cancer: 2) were analyzed, consisting with one patient of Tis, 5 of T1 and 4 of T2. Seven of 10 patients were detectable by US. In unassessable three patients, two cases (Tis and early T1) were too thin to detect by US and one was difficult to evaluate due to the location of the tumor. The minimum thickness of tumor in detectable patients was 2.5 millimeters. In all assessable patients, deep resection margin was negative. The range of tumor thickness measured by US was 2.5 to 18.0 millimeters, and the range of pathological tumor thickness was 1.8 to 9.0 millimeters. Primary site over 2.5 millimeters thickness was detectable by transoral US examination, and was resectable with negative deep margin. Thus, transoral US examination for head and neck cancer was useful to decide deep resection margin in transoral surgery.