Haptic Intracorporeal Palpation Using a Cable-Driven Parallel Robot: A User Study

Objective: Intraoperative palpation is a surgical gesture jeopardized by the lack of haptic feedback which affects robotic minimally invasive surgery. Restoring the force reflection in teleoperated systems may improve both surgeons' performance and procedures' outcome. Methods: A force-based sensing approach was developed, based on a cable-driven parallel manipulator with anticipated seamless and low-cost integration capabilities in teleoperated robotic surgery. No force sensor on the end-effector is used, but tissue probing forces are estimated from measured cable tensions. A user study involving surgical trainees (n = 22) was conducted to experimentally evaluate the platform in two palpation-based test-cases on silicone phantoms. Two modalities were compared: visual feedback alone and both visual + haptic feedbacks available at the master site. Results: Surgical trainees' preference for the modality providing both visual and haptic feedback is corroborated by both quantitative and qualitative metrics. Hard nodules detection sensitivity improves (94.35 +/- 9.1% vs 76.09 +/- 19.15% for visual feedback alone), while also exerting smaller forces (4.13 +/- 1.02 N vs 4.82 +/- 0.81 N for visual feedback alone) on the phantom tissues. At the same time, the subjective perceived workload decreases. Conclusion: Tissue-probe contact forces are estimated in a low cost and unique way, without the need of force sensors on the end-effector. Haptics demonstrated an improvement in the tumor detection rate, a reduction of the probing forces, and a decrease in the perceived workload for the trainees. Significance: Relevant benefits are demonstrated from the usage of combined cable-driven parallel manipulators and haptics during robotic minimally invasive procedures. The translation of robotic intraoperative palpation to clinical practice could improve the detection and dissection of cancer nodules.