Robotic gastric bypass had fewer serious complications but more readmissions than laparoscopic in 394,448 cases

Robotic assistance now accounts for close to half of gastric bypass operations in the United States and Canada. A new analysis of ten years of national registry data finds that the shift has produced a mixed result rather than a clear win: fewer serious complications, but more hospital readmissions and longer time in the operating room.

The study was published in the Journal of Robotic Surgery on September 4, 2026, by a team led by Mohamed Hany of Alexandria University in Egypt, with co-authors in the United Arab Emirates and the United States. It drew on the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program, usually shortened to MBSAQIP, a registry run jointly by the American College of Surgeons and the American Society for Metabolic and Bariatric Surgery. Accredited centers submit standardized data on what happens in the 30 days after each operation.

The analysis covered 411,155 first-time operations performed between 2015 and 2024. Of those, 394,448 were Roux-en-Y gastric bypass and 16,707 were biliopancreatic diversion with duodenal switch. Revisions and conversions from an earlier operation were left out.

Robotic gastric bypass rose from 8.6 percent of cases to 44.0 percent in nine years

Among gastric bypass patients, robotic assistance went from 8.6 percent of cases in 2015 to 44.0 percent in 2024. Duodenal switch started from a higher base and rose from 28.2 percent to 50.3 percent over the same period.

Robotic assistance does not change the anatomy of the operation. A Roux-en-Y gastric bypass still creates a small stomach pouch and reroutes food past most of the stomach and the first stretch of small intestine. The difference is how the surgeon works. In a laparoscopic operation the surgeon stands at the table and holds long instruments directly. In a robotic operation the surgeon sits at a console a few feet away and moves the instruments through the robot. A surgeon is in control either way.

Fewer serious complications, more readmissions, and roughly half an hour more in the operating room

The researchers split the decade into two stretches, 2015 through 2019 and 2020 through 2024, and compared robotic with laparoscopic patients after statistically adjusting for differences in age, body mass index, other medical conditions, laboratory values and several details of the operation itself.

For gastric bypass, patients who had robotic surgery were more likely to be readmitted to hospital within 30 days in both stretches. The odds ratio was 1.23 in the earlier period, with a 95 percent confidence interval of 1.15 to 1.32, and 1.19 in the later period, with an interval of 1.15 to 1.24. An odds ratio compares the odds of an event in two groups. It is not the same as the plain chance of the event, and when an event is uncommon an odds ratio tends to look larger than the underlying difference in percentages.

Serious complications went the other way. Robotic gastric bypass patients had lower odds of them in both periods, at 0.84 with an interval of 0.75 to 0.95, and 0.87 with an interval of 0.81 to 0.93. The researchers defined serious complications as a combined group of events including sepsis, deep or organ-space surgical site infection, bleeding requiring transfusion, blood clots in the lungs or veins, pneumonia, kidney failure, heart attack, cardiac arrest and stroke.

Operations took longer with the robot. The adjusted difference was 39.83 minutes in the earlier period and 26.17 minutes in the later one. Unplanned reoperation was higher with robotic gastric bypass only in the earlier period, at an odds ratio of 1.17 with an interval of 1.05 to 1.30. Deaths within 30 days did not differ between the two approaches in either period.

The duodenal switch findings in the same paper are shakier than the gastric bypass ones

For duodenal switch, robotic surgery was again linked to more readmissions, at 1.38 with an interval of 1.10 to 1.72 in the earlier period and 1.25 with an interval of 1.03 to 1.52 in the later one. Unplanned procedures short of full reoperation were higher in the earlier period, at 1.65 with an interval of 1.16 to 2.35. Operating time was 87.49 minutes longer in the earlier period and 40.85 minutes longer in the later one. Deaths, reoperations and serious complications did not differ.

The authors are explicit that the duodenal switch numbers should be treated as exploratory. That group was far smaller, the events were rarer, and several of those associations faded when the analysis was rerun on only the patients with complete records.

BariatricPal reported on September 3 on a separate MBSAQIP analysis of duodenal switch alone, from a different team at the University of Minnesota, which also found higher 30-day readmission after robotic surgery. What this new paper adds is the gastric bypass picture, covering more than twenty times as many operations, along with the finding that serious complications ran lower on the robotic side even as readmissions ran higher.

A registry can show a pattern, but it cannot prove the robot caused it

This is an observational study, not a randomized trial. Surgeons chose which approach to use, and the statistical adjustment can only account for information the registry actually records. The authors note that MBSAQIP does not capture how many robotic cases a given surgeon or hospital has done, which is likely to affect both the choice of approach and the result. The registry also does not separate operations done entirely on the robot from ones where the robot was used for part of the case.

The 30-day window is another limit. These data say nothing about weight loss, nutrition, long-term complications or cost. The way MBSAQIP codes operations and surgical approach changed partway through the decade, which is why the researchers analyzed the two stretches separately rather than as one continuous trend.

For a patient choosing a surgeon, the practical reading is narrow. This does not say a robotic gastric bypass is a worse operation, and it does not say it is a better one. It says that across a decade of national data the two approaches came out close on the outcomes that matter most, including death, with the robot trading a modest reduction in serious complications for a modest increase in readmissions and a consistently longer operation.