Renal cell carcinoma (RCC), the predominant form of kidney cancer, has increased in incidence and mortality. Partial nephrectomy (PN) is the preferred treatment for resectable renal lesions, with robot-assisted partial nephrectomy (RAPN) combining minimally invasive surgery and robotic precision. However, RAPN challenges surgeons in accurately identifying resection borders within the renal parenchyma. This thesis evaluates the feasibility of integrating electromagnetic tracking (EMT) navigation into RAPN to improve resection guidance. Navigation overlays patient-specific preoperative imaging onto the surgical field, using real-time tracking of surgical instruments and a kidney-affixed sensor to account for kidney movements. The primary objective was to develop and validate an EMT navigation setup for RAPN, evaluating its accuracy and impact on the workflow.
We developed a navigation setup using an electromagnetic tracking system (EMTS) of NDI (Northern Digital Inc., Waterloo, Ontario, Canada), with custom software interfaces and tracking instruments. Conventional RAPN resection volumes were quantified to assess current over-resection and set a comparative standard. EMTS integration in RAPN was evaluated by measuring tracking accuracy in the surgical setup. Accuracy of point- and surface-based registrations were assessed in both phantom and patient settings, including a clinical workflow evaluation using a System Usability Score (SUS).
Our analysis of conventional RAPN demonstrated over-resection in three of four patients, with 62%, 64%, and 165% more healthy parenchymal tissue removed than the 4 mm safety margin required. EMTS evaluation in RAPN showed a median position error of 0.5 mm (0.3 – 0.7 mm) and a median orientation error of 0.3° (0.2 – 0.3°) within the clinically relevant kidney area, indicating minimal distortion from the Da Vinci Surgical System and surgical table. In phantom studies, registration techniques demonstrated a root-mean square error (RMSE) of 1.8±0.1 mm and a target registration error (TRE) of 7.1±1.9 mm. In patient setting, the TRE varied among the three included patients: 2.6±2.5 mm, 44.4 mm, and 3.0±2.5 mm. While EMT navigation showed accuracy potential for enhancing RAPN resection outcomes (< 4.0 mm), an average SUS score of 64.2±2.9 indicated room for improvement. Key focuses included ensuring kidney sensor stability and reducing the time required for navigation-related procedures.
The developed EMT navigation setup provides real-time image-guidance in RAPN, achieving the highest intraoperative precision with point and US-based surface registrations and the kidney sensor placed near the target. Future clinical evaluations are needed to validate this finding and improve its usability for lesion resection. Ultimately, integrating navigation could increase RAPN use over radical nephrectomy, improving RCC treatment outcomes.