A Review of the Role of Robotics in Bariatric Surgery: Finding Our Future?

Introduction

Obesity rates continue to rise in America ¹ and worldwide. As of 2016, the WHO database estimates over 650 million adults >18 years old to have a body mass index (BMI) >30. This number of obese adults has tripled between 1975 and 2016. Weight loss through bariatric surgery continues to be the most effective method to treat this health concern, significantly lowering all-cause mortality of obese patients when compared with medical therapy alone.^2–4 Surgical weight loss treatment becomes more relevant with each passing year of increasing obesity rates. As surgeons, we seek to perform this treatment in a way that achieves optimal patient outcomes. It is thus an area of constant research and investigation. The introduction of laparoscopy brought great improvements for weight loss surgery. Performing these procedures in a minimally invasive fashion resulted in a substantial decrease in operative morbidity.^5,6 Now, with the increasing popularity and availability of robotic surgery, many studies have sought to identify a similar benefit in terms of outcomes and cost. In this study, we form an opinion based on experience and the available literature about the benefit of robotic surgery in the field of bariatrics.

When analyzing the differences in outcomes between robotic and laparoscopic bariatric surgery, it is important to consider the fundamental differences between the two techniques. In essence, robotic surgery sought to improve on the limitations of laparoscopic surgery. To perform surgery from afar, laparoscopy placed the functional end of the instrument further from the surgeons hands, making movements less dexterous and with two-dimensional optics. This, for many, limited the precision and confidence with which meticulous dissection was performed. With the da Vinci Robot, EndoWrist instrument technology allows for increased mobility with seven degrees of movement. The console-controlled camera also brings a high definition 3D operative view to the surgeon. Such enhancements reclaim much of what was desired in laparoscopy.^7,8 Many studies have sought to find the benefit of these advancements when used for bariatric surgery in terms of perioperative outcomes and improved operating time.

Robotic Bariatric Surgery Time and Outcomes

Almost universally in the published bariatric data, use of the robotic platform results in increased total room time in comparison to laparoscopy. These aforementioned advancements may explain the increased operative times seen with the platform. With the increased precision and dexterity afforded by the robot, surgeons may be predisposed to spend more time completing a thorough, bloodless dissection, as well as hand suturing anastomoses or reinforcing staple lines. It would thus be expected that better outcomes be reflected from this practice, and indeed some studies have shown decreased need for transfusion or fewer staple line leaks.^9,10 Unfortunately, this has yet to be the overwhelming consensus among all reported bariatric robotic data.

Despite these observations, certain case-prolonging factors are unlikely to be specific to the surgeon. An OR team unfamiliar with the system can result in added time with instrument allocation/insertion as well as troubleshooting. In many cases, the surgeon is also relying on a bedside assistant for portions of the procedure. Depending on the familiarity of the assistant, the need for instruction may be a factor in increased operating room (OR) times with the robot. An example of this is with the stapling of a gastric sleeve or bypass anastomosis. Placement of the stapler relies on surgeon instruction to the assistant, which may increase times depending on the familiarity of the individual. Although many still opt for an assistant-controlled laparoscopic linear stapler, recently, the emergence of a robotic stapler has brought control of staple firing back to the surgeon. Interestingly, in a small study evaluating the use of the robotic stapler (EndoWrist Stapler system) for gastric pouch formation during Roux-en-Y gastric bypass (RYGB), the authors failed to show an improvement in mean operating time when compared with an assistant-guided linear laparoscopic stapler (+22 minutes for robotic stapler). ¹¹ Some of this was attributed to the unique “tissue sampling” nature of the robotic stapler which, 19% of the time, required adjustment and reclamping before firing. In addition to increased time, more stapler loads and a higher stapling cost were also noted in this single-institution study. ¹¹

It should be noted that although robotic operative times are frequently longer, studies from single institutions (often tracking single surgeon performance) have shown a sharp decrease in total procedure time after a gain of experience. ¹² This should be remembered when reviewing aggregate Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) data, as we may begin to see changing overall times year after year as more surgeons contributing to these data become proficient with the robotic platform.

Certain programs are also faced with the task of resident education. The sleeve gastrectomy is a valuable procedure for resident surgeons to fine tune their laparoscopic skills. As such, it also is a useful procedure to teach residents to use the robotic platform. Ecker et al. demonstrate how residents can perform the console portion of a sleeve gastrectomy without excessive operating times in the skills acquisition phase of their training. ¹³ However, these times did appear to be above the usual average for sleeve performance.

The occurance of globally increased operative times would be justifiable if they yielded improved outcomes. However, several studies have shown increased leaks with robotic gastric sleeves as compared with laparoscopic. Fazl Alizadeh et al. reviewed the robotic and laparoscopic sleeve gastrectomy MBSAQIP data from January to December 2015. They found higher postoperative complications from the robotic group in the form of serious morbidity, leaks, and surgical-site infections in addition to longer operative times. ¹⁴ A different group, using MBSAQIP data collected just 1 year later (January December 2016), also showed an increased rate of leaks (denoted as “organ site infections”) in the robotic group, however, all-cause significant adverse events were equivalent. ⁹ The median robotic time identified was also longer in these data set as well.

Theories exist about the increased leak rate observed by some in robotic sleeve gastrectomy, including a higher probability of the stapler being operated by someone other than the surgeon. Interestingly. however, some authors have found the opposite outcomes in their data. In an analysis of the MBSAQIP 2016 data, Sebastian et al. reported that after adjusting for longer operating times, they found a reduction in reported leaks as well as a decrease in stricture rates with robotic sleeve gastrectomy. ¹⁰ In an earlier 2011 published study, Hagen et al., also noted a reduction in anastomotic leaks with the robot using single-center institutional data. ¹⁵ Undoubtedly, there will likely continue to be variability in leak rates, owing to the variability in surgeon or assistant experience, however, it seems clear that the use of the robotic platform has not offered a clear advantage that translates into preventing these rare occurrences. ⁹

Aside from gastric sleeves, published robotic RYGB outcomes have also been variable over the years. A group reviewing the Bariatric Outcomes Longitudinal Database (BOLD) from 2007 to 2012 found that robot-assisted RYGB had higher rates of complications and reoperation as well as longer operative times. ¹⁶ Several years later, however, a review of the 2016 MBSAQIP data shows somewhat improved outcomes, with no significant differences between laparoscopic RYGB and robotic RYGB in perioperative 30-day rates of significant adverse events, organ-site infection, bleeding, or mortality. ¹⁷

In addition, single-center studies have also shown equivalent perioperative morbidity between robotic and laparoscopic approaches to RYGB.^12,18 Some have even shown fewer severe and overall complications in their robotic cases. ¹⁹ However, another institution found a greater risk of pouch leaks in their robotic RYGB cohort compared with the laparoscopic. ²⁰ Considering this, Hagen et al. published an article with a unique method for leak detection which can use the da Vinci Xi Robot's built-in Fire-fly fluorescent imaging system (Firefly System; Intuitive Surgical, Inc., Sunnyvale, CA). ²¹ As a leak test, a combination of methylene blue and indocyanine green were flushed into the gastric pouch after completion. In 95 patients, 4 were found to have small leaks with ICG fluorescence where none had been previously identified with air or methylene blue alone. While not poised to become the standard of care, this example does emphasize how individual surgeons or groups may identify specific uses for the robotic technology that may suit their particular needs.

Robotic Bariatric Surgery in Special Populations

In light of the mixed outcome data on the use of robotics in routine bariatric surgery, some studies have focused on its value for special populations. These special populations would include the super obese, or those undergoing revisional bariatric procedures. In the super obese, it is thought that the robotic system will prove beneficial in relieving the surgeon of torque fatigue on patients with extra thick abdominal walls. ²² The enhanced ability of the robot to work in small operative spaces may also be of value in super obese patients who may not achieve the same levels of insufflation due to the weight of their abdominal wall as well as decreased cavity space from thick visceral adiposity. In a prospectively collected single-institution database, Gray et al. demonstrated equivalent perioperative outcomes as well as operating times between their morbidly obese, super obese, and super super obese patients when using the robot for bariatric procedures. ²² Increased BMI did not lengthen the procedure time, and reaching equivalent outcomes despite elevated BMIs shows some promise for the technology.

In addition to its use in heavier patients, the precision afforded by the articulating instruments and enhanced visualization would suggest improved ability for the fine dissection required in revisional surgery. This we believe is the area of most notable benefit of robotic technology. A single-center review of a prospectively maintained database saw improved outcomes (shorter length of stay), equivalent safety, and similar operative times with robotic revisional bariatric work. ²³ However, an initial analysis of the MBSAQIP data performed by other groups shows overall longer operative times and increased length of stay for robotic revisional bariatric procedures.^10,24

Robotic Bariatric Surgery and Cost

With burgeoning health care costs, institutions must be highly analytical of where money is spent. Given that many studies thus far have shown variable or mostly equivalent outcomes, to justify using the robot for bariatric procedures, costs must be kept similar to conventional laparoscopy.

Involved in these costs is the initial acquisition of the robotic platform. Aside from the initial expense, an annual maintenance fee as well as repurchasing of limited lifetime instruments must also be considered. Authors have discussed how these amounts can be best amortized by ensuring a high volume of robotic cases, likening the platform to airlines that seek to maximize revenue from their large aircrafts by keeping them in the air as much as possible with quick turnover times. Similarly, a profitable robotic surgery program would seek to use the robot to its full potential to offset initial cost. ¹⁵ This, however, will only be true if costs per case are also kept in close comparison with laparoscopic counterparts.

Many studies over the past decade have, however, continued to find robotic bariatric procedures to prove more lengthy, and thus costly, than their laparoscopic counterparts. ²⁵ In an analysis of the 2015 MBSAQIP data for robotic RYGB, Aminian and colleagues came to the conclusion that the robotic platform was associated with higher hospital resource utilization as operative times were consistently longer and higher readmission rates were found for robotic patients. ²⁶ Still, as we have mentioned, many studies have shown that operating times will typically trend down as the surgeon becomes more familiar with the robotic platform.^12,27 With that taken into consideration, it is surprising to still see that in a single-surgeon/single-center study, despite improvements in operative time, hospital costs remained higher for robotic RYGB compared with laparoscopic (mean $5922 versus $4395). ²⁷

In another Swiss study, Hagen et al. explored the possible cost savings brought on by the robot by both decreasing disposable instrument costs as well as improving outcomes. For a robotic RYGB, their institution acknowledged that by performing totally hand-sewn anastomoses for the jejunojejunostomy and gastrojejunostomy, there were significant savings by not incurring disposable stapler and stapler reload costs. ¹⁵ They continued to find that these hand-sewn anastomoses resulted in fewer leaks and shorter hospital stays which, together, placed the robotic procedure at a lower overall hospital cost than the laparoscopic approach. These outcomes are likely to be institution specific, however, they show that with careful analysis of an individual center's outcomes and purchasing, robotic costs can be minimized.

Conclusion

In conclusion, although initial hopes for robotics' theorized improvements on laparoscopic techniques were highly anticipated, the impact on bariatric surgery quality and results have often fallen short of expectations. While some institutions have found cost-effective ways to utilize the robotic platform to improve their outcomes, no unanimous findings have yet emerged showing clear indications where robotic surgery outperforms laparoscopy in bariatrics. This is likely to be because laparoscopy was already well suited to perform bariatric weight loss procedures, with an admittedly low complication rate. ²⁸ Although we would expect improved outcomes in special groups such as revisional or super obese patients, this has yet to be unanimously shown. It would appear that difficult laparoscopic cases are equally difficult robotic cases and the data have shown little improvement in time or costs. In fact, in nearly all studies, costs were found to be substantially higher when the robot was utilized.

As more surgeons contributing to the national databases pass the learning curve of the robot, an observable shift in outcome trends is likely to develop. In addition, we may find that the robotic platform is better poised for the introduction of newer technologies. The tissue sampling robotic stapler is one example of emerging advancements that might one day prove to offer great benefits in terms of outcomes, cost, and safety. As for cost, we can expect that as the patents on the Intuitive robotic device expire in 2019, market competition may drive down prices in the coming years, bringing the cost of robotic surgery closer to its alternatives.^29,30

Lastly, while the authors provided cautious optimism about the role of robotics in the field of bariatrics, we do believe that for robots to be standard practice, its role must go beyond the improved vision and ergonomics, and evolve toward artificial intelligence, where technology enables us to make better decisions intraoperatively. This will ultimately eliminate many postoperative complications, and at that time, robots will be the standard of care.