Enabling extracorporeal ultrasound imaging with the da Vinci robot for transoral robotic surgery: a feasibility study

Transoral robotic surgery (TORS) is a challenging procedure due to its small workspace and complex anatomy. Ultrasound (US) image guidance has the potential to improve surgical outcomes, but an appropriate method for US probe manipulation has not been defined. This study evaluates using an additional robotic (4th) arm on the da Vinci Surgical System to perform extracorporeal US scanning for image guidance in TORS.

A stereoscopic imaging system and da Vinci-compatible US probe attachment were developed to enable control of the extracorporeal US probe from the surgeon console. The prototype was compared to freehand US by nine operators in three tasks on a healthy volunteer: (1) identification of the common carotid artery, (2) carotid artery scanning, and (3) identification of the submandibular gland. Operator workload and user experience were evaluated using a questionnaire.

The robotic US tasks took longer than freehand US tasks (2.09x longer; \(p = 0.001\) $p=0.001$ ) and had higher operator workload (2.12x higher; \(p = 0.004\) $p=0.004$ ). However, operator-rated performance was closer (avg robotic/avg freehand = 0.66; \(p =0.017\) $p=0.017$ ), and scanning performance measured by MRI-US average Hausdorff distance provided no statistically significant difference.

Extracorporeal US scanning for intraoperative US image guidance is a convenient approach for providing the surgeon direct control over the US image plane during TORS, with little modification to the existing operating room workflow. Although more time-consuming and higher operator workload, several methods have been identified to address these limitations.