Robot assistant versus human or another robot assistant in patients undergoing laparoscopic cholecystectomy

Patients with symptomatic gallstones generally undergo laparoscopic cholecystectomy (key-hole removal of the gallbladder). During this procedure there is only tunnel vision for the surgeon provided by a camera inserted through one of the key-holes. The surgeon operates using instruments while a nurse or another doctor shows the surgeon the operating field using the camera. Thus, the human assistant acts as the 'surgeons' eyes' during the laparoscopic procedure. Recently, robots have been used to assist the surgeons in performing laparoscopic cholecystectomy. Various types of robots exist. Some just hold the camera and can be controlled by surgeons' voice commands or the surgeons' head movements. Adanced robotic systems can hold the camera and all the instruments, all of which are controlled by the surgeon using a console (like in a gaming device). The role of a robotic assistant in laparoscopic cholecystectomy is not known. We sought this information by undertaking a detailed literature search in a systematic way to obtain all the information available from randomised clinical trials. Such clinical trials, if designed well, provide the best estimate of the true effects of interventions.

A detailed and systematic review of the literature revealed that there were six randomised clinical trials including 560 patients. One trial involving 129 patients did not state the number of patients randomised to the two groups. Of the remaining 431 patients in the remaining five trials, 212 patients underwent laparoscopic cholecystectomy with the help of robot assistant and 219 patients underwent the same procedure with the help of a human assistant. All the trials were at high risk of bias (that is, they were prone to systematic underestimation of harms or overestimation of the benefits of the robotic assistant group or the human assistant group because of the beliefs of the people conducting the trial) and errors due to play of chance. Mortality and surgical complications were reported in only one trial with 40 patients. There were no mortality or surgical complications in either group in this trial. Mortality and morbidity were not reported in the remaining trials. Quality of life or the proportion of patients who were discharged as day-patient laparoscopic cholecystectomy patients were not reported in any trial. There was no significant difference in the proportion of patients who underwent conversion to open cholecystectomy or in the operating time between the two groups. In one trial, about one sixth of the laparoscopic cholecystectomies in which a robot assistant was used required temporary use of a human assistant. In another trial, there was no requirement for human assistants. One trial did not report this information. It appears that there was little or no requirement for human assistants in the other three trials. Robot-assisted laparoscopic cholecystectomy does not seem to offer any significant advantages over human-assisted laparoscopic cholecystectomy. However, our present evidence base is limited by trials that all have high risk of systematic errors (potential to underestimate harms or overestimate benefits of the robot assistant group or the human assistant group) and random errors (that is, play of chance). Therefore, further well-designed randomised trials with low risk of systematic errors and low risk of random errors are needed.

Authors' conclusions: 

Robot assisted laparoscopic cholecystectomy does not seem to offer any significant advantages over human assisted laparoscopic cholecystectomy. However, all trials had a high risk of systematic errors or bias (that is, risk of overestimation of benefit and underestimation of harm). All trials were small, with few or no outcomes. Hence, the risk of random errors (that is, play of chance) is high. Further randomised trials with low risk of bias or random errors are needed.

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Background: 

The role of a robotic assistant in laparoscopic cholecystectomy is controversial. While some trials have shown distinct advantages of a robotic assistant over a human assistant others have not, and it is unclear which robotic assistant is best.

Objectives: 

The aims of this review are to assess the benefits and harms of a robot assistant versus human assistant or versus another robot assistant in laparoscopic cholecystectomy, and to assess whether the robot can substitute the human assistant.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded (until February 2012) for identifying the randomised clinical trials.

Selection criteria: 

Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing robot assistants versus human assistants in laparoscopic cholecystectomy were considered for the review. Randomised clinical trials comparing different types of robot assistants were also considered for the review.

Data collection and analysis: 

Two authors independently identified the trials for inclusion and independently extracted the data. We calculated the risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI) using the fixed-effect and the random-effects models based on intention-to-treat analysis, when possible, using Review Manager 5.

Main results: 

We included six trials with 560 patients. One trial involving 129 patients did not state the number of patients randomised to the two groups. In the remaining five trials 431 patients were randomised, 212 to the robot assistant group and 219 to the human assistant group. All the trials were at high risk of bias. Mortality and morbidity were reported in only one trial with 40 patients. There was no mortality or morbidity in either group. Mortality and morbidity were not reported in the remaining trials. Quality of life or the proportion of patients who were discharged as day-patient laparoscopic cholecystectomy patients were not reported in any trial. There was no significant difference in the proportion of patients who required conversion to open cholecystectomy (2 trials; 4/63 (weighted proportion 6.4%) in the robot assistant group versus 5/70 (7.1%) in the human assistant group; RR 0.90; 95% CI 0.25 to 3.20). There was no significant difference in the operating time between the two groups (4 trials; 324 patients; MD 5.00 minutes; 95% CI -0.55 to 10.54). In one trial, about one sixth of the laparoscopic cholecystectomies in which a robot assistant was used required temporary use of a human assistant. In another trial, there was no requirement for human assistants. One trial did not report this information. It appears that there was little or no requirement for human assistants in the other three trials. There were no randomised trials comparing one type of robot versus another type of robot.

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