NATIONAL HARBOR, Md.—Using a robotic platform for metabolic procedures may require slightly more operative time but can reduce complications and hospital readmissions for patients with a body mass index greater than 65 kg/m2, new research shows.
These results were presented at the American Society for Metabolic and Bariatric Surgery 2025 Annual Meeting by lead author Hope Jackson, MD, a clinical associate professor of surgery at the University of Michigan Medical School, in Ann Arbor.
A large body habitus can limit operative exposure and impact fine motor movements, leading to a more challenging surgery, Dr. Jackson said. “Robotic surgery may mitigate these challenges through advances in imaging, ergonomics, and instrumentation, but it’s really unclear if these advances actually translate to improve outcomes.”
She and her colleagues set out to examine the impact of robotic surgery on bariatric outcomes stratified by body mass index groups. They reviewed records from the statewide Michigan Bariatric Surgical Collaborative registry of all 99,532 patients who underwent laparoscopic procedures and 13,167 who had robotic bariatric procedures from 2006 to 2024. They divided patients into three BMI groups—35 to 49 kg/m2, 50 to 65 kg/m2, and 65 kg/m2 or greater—and compared postoperative outcomes and patient demographics for the two most popular procedures: sleeve gastrectomy and Roux-en-Y gastric bypass.
Patients undergoing robotic sleeve gastrectomies across BMI categories had longer mean operative times, were more likely to undergo surgery at a teaching hospital, and tended to have a concurrent cholecystectomy, Dr. Jackson said.
For robotic sleeve gastrectomies, surgeons found no differences in overall risk-adjusted complications between BMI groups. However, patients with a BMI of 50 to 65 kg/m2 had significantly lower readmission rates compared with those in the same BMI group undergoing the laparoscopic approach (2.3% vs. 6.4%; P<0.0001). Regardless of BMI, patients undergoing robotic sleeve gastrectomy were prescribed significantly fewer opioids in 2023 (52.6 morphine milligram equivalent [MME] vs. 84.8 MME; P<0.0001).
Regarding Roux-en-Y gastric bypass, patients undergoing the robotic approach across BMI categories also had longer mean operative times and were more likely to have surgery in a teaching hospital. They also were more likely to undergo concurrent hiatal hernia repair.
Among patients with a BMI greater than 65 kg/m2, those who had robotic procedures had lower overall risk-adjusted complication rates (9.2% vs. 13.9%; P=0.0087) and readmission rates (2.3% vs. 6.4%; P<0.0001) compared with those treated with the laparoscopic approach. Patients in the lower BMI terciles had lower infection rates using the robotic approach.
More robotic gastric bypasses were performed in the BMI greater than 65 kg/m2 group (57% robotic vs. 43% laparoscopic). Those undergoing robotic surgery were more likely to be female, African American, and Medicaid-insured. They also had higher rates of non–insulin-dependent diabetes and lower rates of insulin-dependent diabetes and liver disease than patients undergoing laparoscopic surgery. More patients with a BMI greater than 65 kg/m2 underwent robotic gastric bypass in 2023, Dr. Jackson said.
There were lower overall adverse outcomes for robotic approaches in patients with a BMI greater than 65, and robotic gastric bypass became more common in 2023 for patients with a BMI greater than 65. “Now that we have our complete data set for 2024, it’ll be interesting to see if that trend holds up,” Dr. Jackson said. Regardless of BMI, opioids were prescribed at a lower rate for robotic sleeve gastrectomies.
During the discussion, one attendee noted that the findings were directly at odds with the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) data registry, where every category of patients has higher readmissions.
Dr. Jackson noted the Michigan Bariatric Surgical Collaborative tracks different patients than the MBSAQIP data registry and that her group’s findings could represent statewide practices that are not generalizable to national registries.
More information, such as reasons for readmissions, would be necessary to assess which platform is better, Shanu N. Kothari, MD, the chair of surgery for Prisma Health in Greenville, South Carolina, told General Surgery News. For example, every operation takes longer with the robot.
It’s possible that selection bias played a role, in that if a surgeon knew the patient had a higher BMI as well as an abdominal hernia, they would know that the wrist articulation offered by the robot would allow them to address the hernia better technically and so they would choose that platform, he said.
“If your patient has a BMI greater than 65, and if you are trained in robotic and straight stick, you would take that robot every time if you have access to that room—not necessarily for the patient’s benefit but for the surgeon’s benefit, the ergonomics,” Dr. Kothari added, noting that when he performs a laparoscopy on a patient with a high BMI he feels strain in his neck and shoulders, whereas the robot overcomes the abdominal wall torque. “There is a natural tendency for surgeons that have skills in both—for the more complex cases that they think are going to be harder—to gravitate to the robotic platform when they can.
“What’s missing is a prospective, randomized trial—straight stick to robotic—to truly answer these clinical questions,” he said.
Drs. Jackson and Kothari reported no relevant financial disclosures. Some of the study co-authors received salary support or honoraria from Blue Cross Blue Shield for leadership and participation in the surgery collaborative.
This article is from the December 2025 print issue.
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