A Cochrane review included 6 studies with a total of 560 subjects. In five trials 431 patients were randomised, 212 to the robot assistant group and 219 to the human assistant group. There was no statistically significant difference between the robot-assistant group and the human assistant group for morbidity, conversion to open cholecystectomy (RR 0.90, 95% CI 0.25 to 3.20; 3 studies), total operating time (MD 5 minutes, 95% CI -0.55 to 10.54; 4 studies), or hospital stay (MD 0.00 days, 95% CI -0.47 to 0.47; 1 study). The instrument set-up time was significantly longer in the robot-assisted group than the human-assisted group (MD 12.92 minutes, 95% CI 1.92 to 23.92; 2 studies). In one trial, about one sixth of the laparoscopic cholecystectomies in which robot assistant was used, required temporary use of a human assistant. It appears that there was little or no requirement for human assistants in 3 studies. Surgeons preferred a robot assistant to a human assistant in 2 of the 3 trials, which reported surgeons' preference. The previous experience of the surgeons in the use of a robot assistant varied from none to three previous procedures. 2 trials did not quantify the experience. All the trials included only elective laparoscopic cholecystectomy.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment and lack of blinding), by inconsistency (heterogeneity in interventions and outcomes) and by imprecise results (limited study size for each comparison).