Table 2.

Current status of haptic feedback in RAS

Subject	Study purpose	Conclusion	Level of evidencea	Literature reference
Consequences
Influence on operative times of absence of haptic feedback	Compare robotically and traditionally performed laparoscopic colorectal surgery	Absence of haptic feedback prolongs operative times in robot-assisted colorectal surgery	1b	[47]
	Trial of robot-assisted vs. laparoscopic Nissen fundoplication	Absence of haptic feedback prolongs operative times in robot-assisted Nissen fundoplication	1b	[48]
	Study the feasibility of the Nissen procedure using the da Vinci robot and evaluate the benefits and costs new technique compared with the conventional laparoscopic approach	Absence of haptic feedback prolongs operative times in robot-assisted cholecystectomy	1b	[49]
	Evaluate the efficiency and feasibility of robotically assisted cholecystecomy compared with standard laparoscopic cholecystectomy.	Absence of haptic feedback prolongs operative times in robot-assisted coronary artery bypass surgery	1b	[50]
Influence on surgical performance of absence of haptic feedback	Does haptic feedback, in the form of sensory substitution, facilitate the performance of surgical knot tying?	Haptic feedback increases consistency, precision, and performance in robotic knot tying	3b	[7]
		Without haptic feedback, sutures and tissues are torn, even by experienced surgeons
	Role of force feedback in blunt, surgical, dissection	Absence of force feedback increased the number of errors that damage tissue by factor 3	3b	[51]
Possible solutions
Alternative forms of feedback	Does haptic feedback, in the form of sensory substitution, facilitate the performance of surgical knot tying?	Visual sensory substitution helps to apply more consistent, precise, and greater tensions to fine suture materials without breakage during RAS	3b	[7] [51]
	Overview of research in dexterous manipulation	Audio feedback is proven as a valuable sensory substitution	4	[55]
Addition of haptic feedback	Test pneumatic haptic feedback actuator array, suitable for mounting on surgical robotic tools	Pneumatic balloon-based actuation is a viable solution for generating haptic feedback in RAS	3b	[55] [56]

Studies were conducted as literary review, individual case–control study, prospective randomized trial, or randomized clinical trial

^aBased on the guidelines of the Oxford Centre of Evidence-based Medicine Levels of Evidence [17]