Ring-augmented SG betters standard SG for greater weight-loss durability at 36 months

Ring-augmented sleeve gastrectomy (Ra-SG) achieved statistically greater weight-loss durability at 36 months compared with standard sleeve gastrectomy (SG), according to the outcomes from a randomised clinical trial by researchers from Egypt. They also reported that Ra-SG has a lower incidence of clinically significant RWG and smaller gastric pouch volumes at three years.

According to the authors, although Ra-SG has the potential to improve SG by placing a non-adjustable ring (MiniMizer Ring, Bariatric Solutions International) around the proximal gastric pouch after sleeve creation, to provide maintained restriction, prevent pouch dilation and improve long-term weight maintenance, robust evidence from large-scale, randomised controlled trials with extended follow-up periods is still evolving.

Professor Mohamed Hany

“Despite the limited availability of randomised data in patients with severe obesity (BMI ≥50kg/m²), there remains a need to determine whether the anatomical durability offered by Ra-SG translates into superior weight maintenance, sustained control of obesity-related diseases, and an acceptable safety profile in this high-risk group,” explained Professor Mohamed Hany from Alexandria University and Consultant of Bariatric Surgery at Madina Women’s Hospital, Alexandria, Egypt. “This study compares the mid-term efficacy and safety of Ra-SG with the conventional non-ring augmented SG in adults with a BMI>50 kg/m² over a 36-month follow-up period, focusing on weight loss durability, resolution of obesity-related diseases, complication profile, and patient-reported outcomes, to provide a better understanding of the role of Ra-SG in the management of severe obesity and provide valuable insights for clinical decision-making in metabolic and bariatric surgery (MBS). “

This study was conducted as a single-centre, prospective, single-blind, parallel-group, randomized controlled trial at the Alexandria Medical Research Institute, Alexandria University, Alexandria, Egypt, a high-volume centre for MBS. The primary objective was to compare the efficacy of Ra-SG vs against standard (SG) in adults with a BMI>50 kg/m² over a follow-up period of 36 months. The primary endpoint was the between-group difference in percentage total weight loss (%TWL), percentage excess weight loss (%EWL), and change in body mass index (BMI) at 6, 12, 24 and 36 months postoperatively. %TWL was expressed as the percentage reduction from baseline body weight, and %EWL as the percentage of preoperative excess weight (calculated relative to an ideal body weight corresponding to a BMI of 25 kg/m²) lost at each follow-up interval.

Outcomes

In total, 219 participants were randomised into two groups with 111 participants received Ra-SG and 108 received conventional SG. Follow-up was performed at six months, one year, two years and three years, with minimal loss to follow-up. The loss to follow-up rate was 8.1% in the Ra-SG group and 9.3% in the conventional SG group by 36 months.

The mean age of participants included in the study was 37.7±10.2 years, with no significant difference between groups (p=0.928). Females constituted 66.7% (n=146) of the participants, with no significant differences between groups (p=0.474). Baseline BMI averaged 53.7±2.8 kg/m² in SG and 53.8±2.9 kg/m² in Ra-SG (p=0.847).

Both groups demonstrated substantial weight reduction after surgery, with a significantly greater weight loss was observed in the Ra-SG group only at year three. At 36 months, %TWL declined slightly in both cohorts but was significantly greater in the Ra-SG (48.8±8.3% vs. 45.5±9.0%; p=0.008). BMI at 36 months 27.5±4.4 vs. 29.3±4.7 kg/m² (MD=1.77; 95% CI 0.52–3.03; p=0.006). BMI reduction plateaued after the first postoperative year, but Ra-SG maintained a significantly lower mean BMI at 36 months.

At 36 months, mean absolute recurrent weight gain (RWG) from baseline was significantly lower in the Ra-SG group vs. the SG group (2.7±6.9 kg vs. 7.6±10.2 kg, p<0.001). As a percentage of the maximum weight lost, RWG% was 3.4±7.6% in Ra-SG vs. 9.8±12.9% in SG (p<0.001). Clinically significant RWG, defined as ≥30% RWG from nadir, occurred in 5.9% of Ra-SG patients compared with 16.3% in SG (p=0.033). At three years, gastric pouch volumetry resulted in a smaller mean pouch volume in the Ra-SG group (160.1±8.9 mL) vs. the SG group (194.2±10.3 mL, p<0.001).

Clavien–Dindo grade I events occurred in 9.3% of SG and 14.4% of Ra-SG patients (p=0.332); grade II in 0.9% of each group (p=1.000); grade IIIa was absent in both arms; and grade IIIb occurred in 0.9% after SG versus none after Ra-SG (p=0.989). No grade IV–V complications were observed.

Overall, any early Clavien–Dindo event occurred in 11.1% of SG and 15.3% of Ra-SG (p=0.473). In the SG group, by year three, revisional surgery included one conversion to RYGB for reflux, four conversions to RYGB for recurrent weight gain (RWG), two conversions to RYGB for combined RWG and reflux, and two conversions to OAGB for RWG. In the Ra-SG group, two patients required conversion to RYGB in the second postoperative year, one for reflux and one for RWG. Two additional Ra-SG patients underwent ring removal for intolerance in the second year.

Gastroesophageal reflux disease was observed in 17.3% of SG and 19.6% of Ra-SG patients (p=0.818). Esophagitis grade C was uncommon, occurring in 2.0% of SG and 1.0% of Ra-SG (p=0.616). Hiatal hernia was detected in 4.1% of SG and 4.9% of Ra-SG (p=1.000). Constriction at the incisura angularis was found in 3.1% of SG and in none of the Ra-SG patients (p=0.116). Across follow-up, both groups demonstrated significant improvements in nutritional, metabolic, and endocrine markers.

“Overall, Ra-SG is a reasonable option for patients at high risk of RWG and with a BMI>50 kg/m², provided that counselling addresses stricter eating behaviour and the minor possibility of ring-related reoperation,” Hany concluded. “Future research should move beyond single-centre proof of-concept trials toward large-scale, multi-centre studies with follow-up beyond five years. Such trials should compare Ra-SG not only to SG but also to other ring-reinforced procedures, incorporating comprehensive nutritional assessments and standardized patient-reported outcomes.”

The findings were reported in the paper, ‘Ring-Augmented Versus Non-Ring Augmented Sleeve Gastrectomy in Patients with BMI>50 kg/m²: 3-Year Follow-up of a Randomized Controlled Trial’, published in Obesity Surgery. To access this paper, please click here (log-in maybe required)