Spatially Compact Visual Navigation System for Automated Suturing Robot Toward Oral and Maxillofacial Surgery

The development of an automated suturing robot for oral and maxillofacial surgery (OMS) has long been a challenging task, mainly due to the spatial constraints in the oral cavity, which make intraoral navigation difficult to realize. In this article, we propose a spatially compact visual navigation system for a single-arm suturing robot to enable real-time high-precision navigation during the intraoperative stage. Correspondingly, a two-stage intraoperative navigation framework is designed to achieve intraoral and extraoral navigation. By designing a novel mouth opener with a fixed endoscope, the navigation information from different modules can be aligned. By strategically placing flexible position-sensitive visual markers on the robot body, end-effector, and mouth opener, precise pose information can be acquired without taking up additional space, thus guiding the robot to automatically perform the suturing process. In addition, we design a normal vector guided-bundle adjustment (NVG-BA) module and a dynamic region of interest (ROI) extraction module to improve the system performance. We constructed a real suturing robot system using the proposed visual navigation framework and designed a large number of localization accuracy experiments. All of these experiments collectively demonstrate the exceptional localization accuracy and safety provided by the proposed navigation system, surpassing previously reported OMS navigation systems, all while avoiding any additional occupation of intraoral space. Finally, the system completed an automated suturing process on a simulated wound of a head phantom, demonstrating the automated suturing capability of the system.