To evaluate the performance of a novel master-slave transurethral surgical robot system and test its safety and effectiveness.

In September 2021, two urologists (A and B) applied transurethral surgery robot prototype on simulate human tissue model experiments. The transurethral surgical robotic systems used in this study include: master-end control platform, slave-end surgical platform, and end-effector. The main end control platform adopted Omega7 force feedback main hand as the main controller, and the degrees of freedom include: up and down translation, left and right translation, front and back translation, end rotation, end pitch, end swing, end operation. The end-operated surgical platform adopts the Med 7 seven-degree-of-freedom medical collaborative robotic arm to apply precision through the end effector operated resectoscope. The end effectors were modular in design for maximum compatibility with existing surgical instruments. The two doctors routinely assembled the resectoscope and the transurethral surgical robot 20 times each to calculate the assembly time. The routine assembly time of the resectoscope included the time when the lens and light source were connected after the resectoscope had been installed, and the doctor entered the experimental module with the resectoscope in hand. The time to assemble the surgical robot included the time to install the resectoscope with the end effector and connect the lens and light source to enter the experimental module. Two doctors performed 25 simulated prostate resection and 5 simulated bladder resection procedures. The small intestine, heart and stomach of pigs were sutured to construct urethra, prostate and bladder structures that simulated human body: urethra (pig small intestine) was 16-18 cm long, prostate (pig heart) size was about 5 cm×5 cm×6 cm, and bladder (pig stomach) capacity was 250-300 ml. The model was placed in a 3D printed sleeve to simulate the fitting of the urethra to the silicone penis. Prostate resection surgery: the doctor operated the handle on the main end control platform, controld the slave actuator through human-computer interaction, and excisesed the "prostate" around the fixed point under direct vision, simulating standard transurethral prostatectomy, the resection ranges from the bladder neck to the tip of the prostate, and the two lobes and middle lobes were removed. Each operation lasted 40 minutes and the weight of the removed tissue was recorded. Transurethral esection of the bladder: each procedure involved removal of the triangle, bilateral walls, and apical area of the bladder to record the occurrence of perforation. The accuracy of master-slave operating distance, operation attitude accuracy, master-slave operation attitude repeatability, fixed point accuracy, master-slave control start delay time and master-slave control following delay time, robotic arm swing range, limit site and other indicators of the robot were verified by surgery.

The positioning accuracy of the end effector of transurethral surgical robot was less than 0.5 mm, the accuracy of master-slave operation distance was ≤0.5 mmthe repeatability distance was ≤0.2 mm, the accuracy of master-slave operation attitude was a≤0.30°, the angle b≤0.30°, the angle C≤0.15°, the accuracy of the fixed point ≤is 0.6 mm, the maximum activity space of the robotic arm was a hemispherical space with a radius of (1 493±5)mm. The delay time of master-slave control startup and master-slave control follow-up delay time did not exceed 100ms; When the end of the manipulator was collided by an external force during the movement, the system could automatically stop the movement of the manipulator, at this time the external force was(70±7) N, and the fixed point setting range was 30-170 mm. The assembly time of transurethral surgery robot by Doctor A and Doctor B was (111.35±57.88) s and (111.70±58.30), respectively.The time of routine assembly resectoscope was (44.90±4.89) s and (44.90±5.16) s, respectively, and the difference between the routine assembly time and robot assembly time of Doctor A and Doctor B were not statistically significant(P=0.679 and P=0.996), the assembly time of the two doctor robots was more than the conventional assembly time(P=0.001 and P=0.001). The average weight of prostate tissue resection in experiments was (43.60±12.42)g and (43.45±12.63)g, respectively. No significant difference was found between them(P=0.954). During the simulated bladder electrosurgery, the robot system could successfully complete the resection of the triangular region, bilateral walls, and top tissues of the bladder. In the surgical experiment, the system operated smoothly, without mechanical failure, module damage, perforation, and other complications.

The transurethral surgery robot might be a choice for transurethral surgery.

Transurethral surgical; Robot; Remote center of motion; Human-computer interaction; Master-slave control