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Role of robotics in bariatric surgery

A maximal benefit of robotics can be seen in more complicated bariatric surgeries, especially gastric bypass, and tasks involving anastomotic suturing
Sheraz R Markar MRCS 
Marta Penna MRCS 
Majid Hashemi FRCS MD
Centre for Weight loss,
Metabolic and Endocrine Surgery,
University College London Hospital,
London, UK
The exponential rise in rates of obesity worldwide has been closely followed by a rapid increase in the number of bariatric procedures performed. In 2008, an estimated total of 344,000 bariatric procedures were performed worldwide, 47% of which were Roux-en-Y gastric bypass (RYGB).(1) Buchwald et al showed by meta-analysis the clear metabolic benefits of bariatric surgery, with 78.1% of obese diabetic patients having complete resolution of diabetes mellitus and improved or resolved diabetes in 86.6% of patients following surgery.(2) 
The US Food and Drug Administration first approved the use of robotic surgery on humans in the year 2000. To date, only the da Vinci Surgical System (DVSS) remains and is the main supplier of robotic instrumentation worldwide. Several technical advantages have been attributed to robotic surgery over open and laparoscopic surgery. These include better visualisation with a three-dimensional image, seven degrees of freedom and anti-tremor filters to enable more precise manipulations and increased dexterity by downscaling the surgeon’s movements. The robotic arms liberate the surgeon from the restraints of entrance ports and the thick abdominal wall possessed by many bariatric patients, thereby allowing better ergonomic positioning. In turn, this leads to better tissue dissection and more accurate suturing. 
Cost remains a major issue limiting the widespread use of robotic surgical devices. Currently, the purchase of the DVSS robotic device costs between $500,000 to 2.2 million depending on model, age, and choice of components. Surgical instruments designed for use with the robotic arms can be used a maximum of ten times, with instrument costs ranging from $1100 to $8000. Additional yearly maintenance costs, which are approximately 10% of the purchase price, must also be factored in. Hagen et al(3) recently conducted a prospective study comparing postoperative complications, mortality, intensive care unit stay, hospitalisation and operative room costs between open, laparoscopic and robotic surgery for RYGB.
Robotically sutured anastomoses showed significantly fewer leaks compared with stapled anastomoses during laparoscopy. The management of anastomotic leak generated very high costs in this study. Hagen et al concluded that robotic RYGB could be cost effective by balancing greater robotic overhead costs with the savings associated with avoiding stapler use and costly management of anastomotic complications. However, the article did report a relatively high leak rate of 4% for the laparoscopic RYGB group (compared with the commonly published 2% leak rate), which they attributed to the procedures being performed by surgeons during their early learning curve phase. 
A second disadvantage reported for the robotic device is the prolonged setup and operative time compared with the laparoscopic equivalent. However, studies have reported mixed findings and, in general, the more experienced the team become with handling the robot, the shorter the setup and operative time become. Many centres would advocate the training and employment of dedicated robotic theatre staff, who through experience become comfortable and more efficient with the setup and use of the robot. 
Robotic gastric bypass surgery
In 2003, Jacobsen and colleagues(4) reported their findings on a multi-institutional series of 107 robotically assisted RYGBs using sutured gastrojejunostomy anastomoses. Jacobsen’s outcomes were very promising, with no major post-operative complications, in particular no anastomotic leaks, and no mortalities. The surgeons reported a number of technical advantages of using a robotic versus laparoscopic approach including stiffer instruments and greater mechanical power to overcome the thick abdominal wall in obese patients allowing the hand-sewn gastrojejunal anastomosis to be performed more easily, avoidance of the stapling device which eliminates complications caused by passing the anvil nasogastrically and a smaller gastric pouch can be created as the intraluminal stapler is not required.
The concept of the learning curve for robot-assisted versus laparoscopic RYGB has been investigated in several publications. Buchs et al(5) published a case series of 64 consecutive robot-assisted RYGB procedures performed by a single surgeon to evaluate the learning curve for this operation using the cumulative sum (CUSUM) method. The resulting learning curve appears to consist of two different phases: phase 1 comprises the first 14 cases followed by the last 50 cases in phase 2.
A significant reduction in the operative time was observed between phase 1 (288.9 minutes) and phase 2 (223.6 minutes; p=0.0001). Minute per body mass index (BMI) also decreased between the initial and final phase. Importantly, there was no significant difference noted in terms of postoperative outcomes between the two phases although hospital stay was approximately one day longer for the first 14 cases. Buch’s data suggests that the learning curve for robot-assisted RYGB can be achieved with only 14 cases.
By contrast, 75–100 cases are commonly reported in the literature for laparoscopic RYGB,(6–8) a technically challenging procedure requiring advanced laparoscopic skills. This is an important comparison to make given the increased operative time and morbidity rates usually associated with the beginning of the learning curve; leak rates as high as 7% have been reported by Schauer et al(9) for laparoscopic RYGB during this initial phase. However, previous laparoscopic experience should be taken into account when comparing robotic versus laparoscopic learning curves and outcomes as one may predict that a surgeon with advanced laparoscopic skills is likely to accomplish good outcomes more quickly when starting robotic surgery compared to a surgeon with less laparoscopic experience. 
More recently, Markar et al(10) published a pooled analysis comparing robotic versus laparoscopic (RRYGB versus LRYGB) identifying seven relevant studies (six comparative and one randomised, controlled trial) with a total of 1686 patients. The primary outcomes analysed were the incidence of anastomotic leak and stricture, while secondary outcomes measured were postoperative complications, operative time and length of hospital stay.
The results of the pooled analysis revealed a significantly reduced incidence of anastomotic stricture in the robotic group (pooled odds ratio=0.43; 95% CI=0.19 to 0.98; p=0.04) but no significant difference between the robotic and laparoscopic group for the other measured outcomes. Possible reasons for such findings suggested relate to the improved three-dimensional visualisation and better ergonomics with the robotic technique that leads to more precise tissue dissection with sufficient mobilisation and accurate tension-free suturing of the anastomosis. Subclinical anastomotic leaks in the LRYGB may also result in structuring of the anastomotic site as healing and scarring takes place. 
Robotic gastric band surgery
The first study to compare robotic versus laparoscopic gastric banding was published in 2003 by Muhlmann and colleagues.(11) The study included 20 patients evenly divided into DVSS or CLS for either adjustable gastric band (12 patients) or an implantable gastric stimulator (eight patients). The key findings from the comparative study were a significantly longer operative time (by 40 minutes) and greater cost (>$3200) for the DVSS approach compared to the CLS method. No significant differences were noted between the two groups with regards to length of hospital stay or number of postoperative complications. 
More recently, a retrospective comparative study was conducted by Edelson et al(12) involving 407 consecutive patients who underwent either robot-assisted (RAGB) (287) or conventional (120), laparoscopic adjustable gastric banding (LAGB). The study showed no significant differences in intraoperative or postoperative adverse events, length of hospital stay and operative time between the two groups. The absence of a clear benefit from robotic surgery over the conventional laparoscopic approach in terms of reduced adverse events was attributed to a possible ‘ceiling effect’. As LAGB is already a very safe procedure with minimal complications, it leaves very little room for improvement and the possibility to show a significant better outcome. 
A sub-analysis of the operative time divided according to body mass index (BMI) was carried out and showed a significantly shorter surgery time associated with using the robotic approach for patients with a BMI ≥50kg/m2 (91.3±19.7 minutes for robotic versus 101.3±23.7 minutes for CLS; p=0.04). The authors suggested the finding could be the result of several advantages of the robotic technique over CLS in terms of stiffer instruments and increased mechanical power achievable with the robot on patients with thick abdominal walls. 
Alqahtani and colleagues(13) conducted a similar retrospective comparative study but in children and adolescents aged 8–21 years. A total of 75 patients were included, 25 of whom underwent robotic AGB (RAGB) and 50 LAGB. No significant differences in complication rate, length of hospital stay or percentage excess weight loss at one year was found between the two groups. Mean operating time was, however, significantly shorter by approximately 24 minutes for LAGB compared with RAGB.
Once again, current robotic systems are safe, effective and feasible for gastric banding even in the younger age group. But, there is an increased operative time with RAGB and at present evidence suggests that the robotic approach does not provide added benefits for this surgical procedure. However, none of these studies were randomised or blinded and long-term outcomes remain largely unknown. This highlights the need for future randomised controlled trials in this field, with appropriate stratification of known confounding variables. 
Robotic sleeve gastrectomy
Few studies have reported their experience using robotic sleeve gastrectomy. Ayloo et al(14) published a prospective comparative study including 69 morbidly obese patients who underwent robotic-assisted sleeve gastrectomy (RASG). The outcomes after RASG were compared with the laparoscopic approach, including 30 and 39 patients respectively. There were no differences between the two groups in terms of morbidity, mortality, length of stay and weight loss. The morbidity after RASG was 3.3% but, importantly, there were no incidences of gastrointestinal leak or staple line bleeding.
A difference in mean operative time was noted between the two surgical approaches with the RASG taking 135 minutes compared with a mean operative time of 114 minutes (p=0.003). However the paper did report that the staple line was oversewn in the robotic group but not in the conventional laparoscopy group. Conclusions drawn from this study were that RASG is a safe alternative approach to sleeve gastrectomy producing good outcomes. 
Diamantis and colleagues(15) published their initial experience with robotic sleeve gastrectomy in patients with a mean BMI of 48.2kg/m2. Data from a smaller sample group of 19 patients with a mean age of 39.4 years was analysed and of whom the majority were women (89%) were analysed. The study also reported zero mortalities or significant morbidities with no conversions to open. Mean excess body weight loss one year postoperatively was 65.5±25.6%, which is comparable to that reported for laparoscopic sleeve gastrectomy. 
A more recent study presented at the Society of American Gastrointestinal and Endoscopic Surgery (SAGES) 2012 annual meeting by Miller et al(16) aimed to determine the best surgical approach to perform longitudinal sleeve gastrectomies. A total of 317 patients were included in a multicentre retrospective review, of which 277 received laparoscopic sleeve gastrectomy while 40 patients underwent robot-assisted LSG. This group also found that the robotic approach had a significantly longer operative time compared to a solely laparoscopic procedure (113 minutes versus 91 minutes respectively; p=0.002).
There was no significant difference in hospital length of stay, which on average was 2.4 days, but interestingly, a significant greater number of readmissions within 90 days occurred secondary to postoperative complications in the laparoscopic group – 12.3% for laparoscopic and 5% for the robot-assisted LSG group (p<0.001). At present, the role of robotics in sleeve gastrectomy remains inconclusive; however, future highly powered randomised controlled trials could help to elucidate any differences in clinical outcomes that exist between laparoscopic and robotic sleeve gastrectomy.
Future potential developments 
Robotic bariatric surgery has repeatedly been shown to be a safe and effective approach to gastric bypass and gastric banding; however, any true consistent benefits over conventional laparoscopy remain to be clearly demonstrated. Robotic surgery does, however, possess a clear and unique advantage over other surgical approaches, that is, the possibility of performing remote or ‘telesurgery’. Interestingly though, a recent international survey conducted by Markar et al(17) exploring the public’s attitude to robotic surgery found that although the majority (52%) of the 155 participants included in the study felt that current robotic surgery is an acceptable procedure to perform, 68% of the responders reported they would be very uncomfortable with the idea of not seeing the operating surgeon in person before or after surgery. Because patient preference and agreement are very important when planning surgery, robotic telesurgery may not be a very popular or embraced option. 
Obesity continues to increase worldwide, and therefore it is most likely that there will continue to be a parallel increase in bariatric surgery. Obese patients represent a unique cohort with important anatomical and physiological challenges that can result in a more complicated recovery following major surgery. Robotic surgery confers several technical advantages over standard laparoscopy including improved three-dimensional visualisation and better ergonomics. This review of the current literature suggests the maximal benefit of robotics may be seen in more complicated bariatric procedures especially gastric bypass. In particular, tasks involving anastomotic suturing may be better performed using robotics, with better visualisation, more precise needle movement and greater accuracy in suturing, resulting in improved clinical outcome as reflected by leak and stricture rate. These benefits of robotics are offset by increased costs and operative time that will limit the cost effectiveness of robotics in less complicated bariatric procedures including gastric banding.
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