Abstract 23: A flexible next-generation robotic system for transoral robotic nasopharyngectomy: A comparative preclinical study

Objective: To compare the technical efficacy and extent of instrument reach in performing transoral robotic nasopharyngectomy with the current da Vinci Si surgical robot system (Intuitive Surgical Inc., Sunnyvale CA) and the flexible next-generation robotic system (Da Vinci SP Surgical System, Model SP999, Endo Wrist SP, Intuitive Surgical, Inc.). Study Design: Preclinical study using human cadaver. Materials and Method: Transoral resection of the nasopharyngeal wall and dissection of the parapharyngeal fat space from midline was performed on one side with the da Vinci Si robotic system and the da Vinci SP robotic system on the contra-lateral side in a fresh cadaver. The soft palate was elevated with sutures. For the da Vinci Si system, a 12-mm 30o telescope facing superiorly with 5-mm Maryland forceps and 5-mm monopolar cautery was used to perform the dissection. For the da Vinci SP system, the flexible camera system with 6-mm monopolar cautery spatula, 6-mm bipolar Maryland forceps and 6-mm prograsp forceps were employed for dissection. Results: The mouth opening was 5 cm. Comparing the surgical view, the da Vinci SP system gave a much wider view with both Eustachian tube opening visible and the whole posterior edge of the vomer in view. In the da Vinci Si system, only the Eustachian tube cushion of the side of dissection was visible and only the attachment of the vomer bone to the roof of the nasopharynx was visible. For instrument reach, the da Vinci SP system can dissect up to 2 cm lateral to the medial pterygoid plate while the da Vinci Si system can only reach 1 cm beyond the medial pterygoid plate laterally. In the da Vinci SP system, all 3 instruments arms together with the flexible camera could be deployed for dissection. Occasional collisions of the robotic arms inside the oral cavity can be resolved by the console surgeon adjusting the positions of the robotic instruments. On the da Vinci Si system, only 2 robotic arms and the camera arm can be deployed as the external part of the robotic arms are bulky and prevented deployment of all 4 arms. External collision of the robotic arms occurred frequently and in several instance required the bedside surgeon to reposition the robotic arms. Conclusion: The flexible next-generation surgical robotic system provided superior visualization of the nasopharynx and allowed dissection with 3 robotic instruments. Compared with a standard robotic system, the flexible next-generation surgical robotic system can reach more laterally into the parapharyngeal space to perform dissection. Citation Format: Raymond King-Yin Tsang, Chris Holsinger. A flexible next-generation robotic system for transoral robotic nasopharyngectomy: A comparative preclinical study [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; April 23-25, 2017; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(23_Suppl):Abstract nr 23.