Improved transoral surgical tool design by CT measurements of the oral cavity and pharynx.

The majority of head and neck cancers arise from the oral cavity and oropharynx. Many of these lesions will be amenable to surgical resection using transoral approaches including transoral robotic surgery (TORS). To develop and control TORS tools, precise dimensions of the oral cavity and pharynx are desirable. CT angiograms of 76 patients were analyzed. For the oral cavity, only the maximum length and width were measured, while for the pharynx, the width, length, and areas of the airway were all measured and the volume calculated. A prototype TORS tool was developed and tested based on the findings and dimensions. The design modification of the tool is in progress. The mean male oral cavity width and length were 93.3 ± 4.3 and 77.0 ± 7.2 mm, respectively, and the mean male pharyngeal width, length, area, and volume were 26.5 ± 7.2 mm, 16.2 ± 8.8 mm, 325 ± 149 mm2 , and 28,440 ± 14,100 mm3 , respectively, while the mean female oral cavity width and length were 84.5 ± 12.9 and 71.0 ± 6.3 mm, respectively, and the mean female pharyngeal width, length, area, and volume were 24.8 ± 5.6 mm, 13.7 ± 3.2 mm, 258 ± 98 mm2 , and 17,660 ± 7700 mm3 , respectively. The developed TORS tool was tested inside the oral cavity of an intubation mannequin. These data will also be used to develop an electronic no-go cone-shape tunnel to improve the safety of the surgical field. Reporting the oral cavity and pharyngeal dimensions is important for design of TORS tools and creating control zones for the workspace of the tool inside the oral cavity.