Pneumatically driven surgical forceps displaying a magnified grasping torque

Vision-based estimation of manipulation forces by deep learning of laparoscopic surgical images obtained in a porcine excised kidney experiment

In robot-assisted surgery, in which haptics should be absent, surgeons experience haptics-like sensations as "pseudo-haptic feedback". As surgeons who routinely perform robot-assisted laparoscopic surgery, we wondered if we could make these "pseudo-haptics" explicit to surgeons. Therefore, we created a simulation model that estimates manipulation forces using only visual images in surgery. This study aimed to achieve vision-based estimations of the magnitude of forces during forceps manipulation of organs. We also attempted to detect over-force, exceeding the threshold of safe manipulation. We created a sensor forceps that can detect precise pressure at the tips with three vectors. Using an endoscopic system that is used in actual surgery, images of the manipulation of excised pig kidneys were recorded with synchronized force data. A force estimation model was then created using deep learning. Effective detection of over-force was achieved if the region of the visual images was restricted by the region of interest around the tips of the forceps. In this paper, we emphasize the importance of limiting the region of interest in vision-based force estimation tasks.

Effects of a force feedback function in a surgical robot on the suturing procedure

BACKGROUND

Currently, widely used robotic surgical systems do not provide force feedback. This study aimed to evaluate the impact and benefits of a force feedback function on the suturing procedure.

METHODS

Twenty surgeons were recruited and divided into young (Y-group, n = 11) and senior (S-group, n = 9) groups, based on their years of surgical experience. The effect of the force feedback function on suturing quality was evaluated using an objective assessment system (A-LAP mini, Kyoto Kagaku Co., Ltd., Kyoto, Japan). Each participant completed the suturing task on intestinal model sheets with the robotic contact force feedback on and off. The task accomplishment time (s), maximal force (Newton, N) applied to the robotic forceps, and quality of suturing (assessed by A-LAP mini) were recorded as performance parameters.

RESULTS

In total, the maximal force applied to the robotic forceps was significantly decreased with the robotic force feedback switched on (median [interquartile range]: 2.8 N (2.3-3.2)) as compared with when the feedback was switched off (3.4 N (2.7-4.0), P < 0.001). The contact force feedback function did not affect the objectively assessed suturing score (18 points (17.7-19.0) versus 18 points (17.0-19.0), P = 0.421). The contact force feedback function slightly shortened the task accomplishment time in the Y-group (552.5 s (466.5-832) versus 605.5 s (476.2-689.7), P = 0.851) but not in the S-group (566 s (440.2-703.5) versus 470.5 s (419.7-560.2), P = 0.164).

CONCLUSIONS

With the contact force feedback function, the suturing task was completed with a smaller maximal force, while maintaining the quality of suturing. Because the benefits are more apparent in young surgeons, robots with the contact force feedback function will facilitate the educational process in novice surgeons.

Impact of a pneumatic surgical robot with haptic feedback function on surgical manipulation

Although robotic-assisted surgery has the advantages of low patient burden and high precision without unsteady hand movements, the lack of tactile sensations may result in unexpected iatrogenic organ damage. The Saroa (Riverfield Inc., Tokyo, Japan) is a pneumatically driven robot that provides real-time haptic feedback to the surgeon. Using the Saroa robot, six examinees performed puffed rice transfer and four of them performed pig lung resection tasks with the feedback function turned on and off. The puffed rice transfer task consisted of transferring 20 grains of puffed rice from the left to the right compartment in the training box. The mean grasping forces during the puffed rice transfer task with the haptic feedback function turned off and on were 2.14 N and 0.63 N, respectively (P = 0.003). The mean grasping forces during the pig lung resection task were lower with the feedback turned on than turned off. The force that the forceps exerted on the grasping object was weaker in both tasks when the haptic feedback function was turned on, suggesting that the feedback function allows gentler handling of tissues, improving patient safety during robotic surgery.

Pneumatically driven surgical forceps displaying a magnified grasping torque

BACKGROUND

Sensing the grasping force and displaying the force for the operator are important for safe operation in robot-assisted surgery. Although robotic forceps that senses the force by force sensors or driving torque of electric motors is proposed, the force sensors and the motors have some problems such as increase in weight and difficulty of the sterilization.

METHOD

We developed a pneumatically driven robotic forceps that estimates the grasping torque and display the magnified torque for the operator. The robotic forceps has a master device and a slave robot, and they are integrated. In the slave side, the grasping torque is estimated by the pressure change in the pneumatic cylinder. A pneumatic bellows display the torque through a linkage.

RESULTS

We confirmed that the slave robot follows the motion of the master, and the grasping torque is estimated in the accuracy of 7 mNm and is magnified and displayed for the operator.

CONCLUSIONS

The pneumatically driven robotic forceps has the capability in the estimation of the grasping torque and display of the torque. Regarding future work, the usability and fatigues of the surgeons must be evaluated.