Seven-year results comparing two stomach surgery revisions for weight regain after sleeve gastrectomy: weight loss, acid reflux, and metabolic safety

All procedures were performed as revisional laparoscopic procedures after SG, and none were converted to open procedures.

RYGB: The Roux-en-Y gastric bypass was performed using a standardized technique. A small gastric pouch (30–50 ml) was fashioned by transecting the previously sleeved stomach approximately 4 cm distal to the gastroesophageal junction with additional trimming performed when necessary to optimize pouch configuration. The alimentary (Roux) limb was constructed with a length of 100 cm, and the biliopancreatic limb measured 125 cm. Both Petersen’s space and the mesenteric defect at the jejunojejunostomy were systematically closed to minimize the risk of internal herniation. No intra-abdominal drains were routinely placed.

SADI-S: After inspection of the abdominal cavity, a retropyloric-retroduodenal dissection was carried out to expose approximately 3 cm of the duodenum distal to the pylorus, which was then transected. The small bowel length was measured from the ileocecal junction, and a 300-cm ileal common channel was constructed. A double layer end- to- side duodeno-ileal anastomosis was created in an isoperistaltic fashion. No intra-abdominal drains were routinely placed.

Demographic and baseline clinical data were obtained from electronic medical records. The variables included age, sex, height, weight prior to SG, nadir weight after SG, and weight prior to revisional surgery. Comorbidity data were collected and classified as diabetes, hypertension, dyslipidemia, asthma, obstructive sleep apnea, and GERD.

Perioperative variables, including operative time and length of stay, were also extracted. Laboratory markers, including hemoglobin, micronutrients, lipid profile, ferritin, folate, vitamin B12, and vitamin D, were recorded at baseline, 1, 5, and 7 years to assess nutritional status at later time points.

At 1-, 5-, and 7-year post-revision follow-up, anthropometric measurements were obtained. Variables included body weight, BMI, percentage excess weight loss (percent EWL), percentage total weight loss (percent TWL), and body weight reduction.

All complications after the operation, such as bleeding, internal hernia, marginal ulcers, dumping syndrome, severe malnutrition, vitamin deficiencies, and iron deficiency anemia, were carefully reviewed through electronic records from surgery to the date of data collection.

The SPSS version 26 was used to perform statistical analysis. Independent samples based on distributions (either independent-sample t-tests or Mann Whitey U tests). Chi-square test or Fisher exact test was used to analyze categorical variables. Kaplan Meier curves were used to determine time-to-event data (e.g., complication-free survival), whereas Cox proportional hazards techniques were employed to estimate outcome predictors. A p-value < 0.05 was considered statistically significant.

The study examined 105 individuals who returned to surgery after unsuccessful sleeve gastrectomy to perform a revisional bariatric surgery, 62 underwent conversion to RYGB, and 43 were converted from SG to SADI-S. The age of both groups was similar as the mean age of RYGB was 40.66 years, SD 9.47, and that of SADI-S was 39.35 years, SD 9.28 (p = 0.48). But there was significant difference in sex distribution. Females constituted 65.8 percent of the RYGB group and 61.5 percent of the SADI-S group (p = 0.01), indicating that there might be gender-related factors that affect the surgical decision-making [4, 5]. Also, SADI-S patients were revised earlier with an average of 3.53 ± 1.29 years after SG as opposed to 4.13 ± 1.31 years in RYGB patients (p = 0.02). It could be indicative of a rapid weight recurrence regain after SG in subjects who received SADI-S as a revisional conversion surgery (Table 1).

Anthropometric measurements (Table 1), indicated that SADI-S patients exhibited higher body weight both before SG and prior to revision. Their pre-SG weight was 141.02/27.14 kg on average in comparison to 128.73/26.95 kg in RYGB patients (p = 0.02). Pre-revision weight was also significantly higher in the SADI-S group (119.05 + 23.53 kg) compared with the RYGB group (107.16 + 21.20 kg; p = 0.008). Accordingly, the SADI-S group had a significantly higher pre-revision BMI (43.51 ± 7.07 kg/m²) compared with the RYGB group (40.22 ± 6.45 kg/m²; p = 0.01) [12–14].

The RYGB and SADI-S groups showed comparable preoperative comorbidity profiles (Table 2). The prevalence of diabetes, hypertension, dyslipidemia, obstructive sleep apnea, and asthma did not differ significantly between groups. Diabetes was present in 11 RYGB and 7 SADI-S patients, and hypertension in 11 and 8 patients, respectively, with non-significant p-values. Although dyslipidemia appeared more frequently in the RYGB group (71.4 vs. 28.6%) (Table 2).

The only significant difference in preoperative comorbidities was the markedly higher prevalence of GERD among RYGB patients (88.6 vs. 11.4%, p = 0.001). This disparity indicates that GERD was a major determinant in selecting RYGB, consistent with its established efficacy in managing refractory reflux [12]. In contrast, the low prevalence of GERD among SADI-S patients suggests that their revisions were primarily driven by weight-related indications.

Intraoperative outcomes (Table 3), did not differ significantly between the RYGB and SADI-S groups, indicating comparable procedural efficiency and perioperative safety. Operative time was similar for both procedures, with RYGB averaging 2:00:45 h and SADI-S 2:03:20 h. Length of hospital stay was likewise comparable (3.69 vs. 3.59 days; p = 0.51) (Table 3).

During the 7-year follow-up, SADI-S consistently achieved superior weight-loss outcomes compared with RYGB (Table 4). Although absolute weight and BMI were similar between groups at each assessment point, SADI-S produced significantly greater reductions in %EWL (53.75 vs. 43.46%, p = 0.05), %TWL (21.63 vs. 15.03%, p = 0.001), and BMI (9.54 vs. 6.07, p < 0.001) at 1 year (Table 4).

These advantages persisted long-term. At 5 years, SADI-S maintained higher %EWL (49.67 vs. 34.94%, p = 0.03), %TWL (20.52 vs. 12.49%, p = 0.001), and BMI reduction (9.27 vs. 5.13, p < 0.001). By 7 years, absolute weight and BMI were comparable, yet SADI-S continued to show superior %TWL (19.59 vs. 13.23%, p = 0.01) and BMI reduction (8.94 vs. 5.44, p = 0.002). These findings are clearly depicted in Fig. 1.

Collectively, these findings indicate that SADI-S provides more durable and clinically meaningful weight-loss outcomes than RYGB as a revisional surgery after inadequate weight loss following sleeve gastrectomy.

Postoperative laboratory assessments (Table 5), at 1, 5, and 7 years demonstrated distinct differences in malabsorption-related parameters between the RYGB and SADI-S groups. Hemoglobin levels remained comparable across all time points. In contrast, calcium levels were consistently lower in the SADI-S group at 5 and 7 years (p = 0.00 and p = 0.04) (Table 5).

Lipid profiles showed more pronounced differences. SADI-S patients exhibited significantly lower total cholesterol at 1, 5, and 7 years (p = 0.002, 0.02, and 0.01), and lower triglycerides at 5 and 7 years (p = 0.001 and 0.006), alongside reduced HDL and LDL at all assessments, with LDL reaching statistical significance at 1 year.

Micronutrient evaluation revealed higher zinc and folate levels in RYGB patients. In contrast, vitamin B12 concentrations were consistently higher after SADI-S.

Comorbidity outcomes (Table 6) were largely comparable between RYGB and SADI-S, with no statistically significant differences for type 2 diabetes, hypertension, dyslipidemia, or asthma.

Diabetes remission or improvement occurred in 44.4% of RYGB and 55.6% of SADI-S patients (p = 0.24). Hypertension outcomes were similar overall, with improvement observed only in the SADI-S group (Table 6).

Dyslipidemia remission or improvement was 66.7% in RYGB and 33.3% in SADI-S (p = 0.99).

Asthma improvement rates were low and did not differ between procedures.

In contrast, GERD outcomes favored RYGB: complete remission or improvement occurred in 95.0 versus 5.0% with SADI-S (p = 0.02), and persistent or progressive GERD was more common after SADI-S.

Postoperative complications (Table 7) were uncommon in both groups, and no statistically significant differences were observed between RYGB and SADI-S. Bleeding occurred in one RYGB patient and in none of the SADI-S patients (p = 0.99). Marginal ulceration was reported more frequently after RYGB, though not significantly so (p = 0.61). Internal hernia occurred only in the RYGB group (two cases), but this difference was also not significant (p = 0.64). Dumping syndrome was more frequently reported after RYGB (81.8 vs. 18.2%), although the difference did not reach statistical significance (p = 0.19) (Table 7).

Nutritional and metabolic complications showed similar patterns between procedures. Vitamin deficiencies were observed in 62.1% of RYGB and 37.9% of SADI-S patients (p = 0.69). Severe malnutrition was rare, occurring in one RYGB and two SADI-S patients (p = 0.74). Iron-deficiency anemia was common in both cohorts—55.1% in RYGB and 44.9% in SADI-S—with no significant difference (p = 0.44).

Notably, neither group experienced anastomotic leak, bowel obstruction, or stricture.

Current evidence indicates that both Roux-en-Y gastric bypass (RYGB) and single-anastomosis duodeno-ileal bypass (SADI-S) are effective revisional procedures following inadequate weight loss after sleeve gastrectomy. However, SADI-S consistently demonstrates superior long-term weight-loss outcomes. Patients undergoing SADI-S achieve significantly greater percentages of excess weight loss (EWL), total weight loss (TWL), and BMI reduction at 1, 5, and 7 years, reflecting more durable weight-loss maintenance [3, 6].

This enhanced effect is likely attributable to the greater malabsorptive component of SADI-S, driven by duodenal diversion and a longer bypassed intestinal segment, which augments long-term metabolic and caloric malabsorption. Such characteristics may be particularly advantageous in patients with higher pre-revision BMI or early failure after sleeve gastrectomy. By contrast, although RYGB produces meaningful weight loss, its mixed restrictive-malabsorptive mechanism may offer comparatively less sustained benefit in higher-BMI revisional populations [6, 13, 15].

Both revisional procedures achieved comparable improvement or remission of obesity-related comorbidities—including type 2 diabetes, hypertension, dyslipidemia, and asthma—with no statistically significant differences between RYGB and SADI-S. These findings suggest that weight loss itself is the principal driver of metabolic improvement before and after revision, regardless of the surgical technique [12, 13].

However, the outcomes for gastroesophageal reflux disease (GERD) differed markedly between procedures. RYGB resulted in significantly higher rates of GERD remission or improvement, consistent with its well-established anti-reflux mechanism that diverts both gastric acid and bile from the esophagus. These results reaffirm RYGB as the preferred revisional option for patients presenting with severe or persistent GERD after sleeve gastrectomy [16].

Operative time and length of hospital stay did not differ significantly between the groups, indicating comparable perioperative efficiency and safety for both RYGB and SADI-S. These findings support the feasibility of performing either procedure as a revisional intervention in experienced bariatric centers. The similarity in early postoperative recovery further reinforces SADI-S as a viable revisional procedure [6, 14].

Early postoperative complications were also comparable. Neither cohort experienced anastomotic leak, bowel obstruction, or stricture, and no significant differences were observed in other early surgical events. These results underscore that, with appropriate patient selection and surgical expertise, revisional bariatric procedures can be performed with low perioperative risk despite the inherent complexity of re-operative surgery [13, 17].

Long-term laboratory follow-up showed that most nutritional parameters—including hemoglobin, albumin, and total protein—remained comparable between the two groups throughout the study period. In contrast, differences emerged in lipid profiles and selected micronutrients. SADI-S patients demonstrated greater reductions in total cholesterol and triglycerides over time, reflecting the more pronounced metabolic effects of this procedure [3, 5, 18, 19].

Both procedures were associated with persistent micronutrient deficiencies, particularly in iron, vitamin D, zinc, folate, and vitamin B12. Although severe malnutrition was rare, these findings underscore the need for lifelong nutritional monitoring after revisional surgery. The greater malabsorptive component of SADI-S, in particular, necessitates strict adherence to postoperative supplementation to mitigate long-term deficiency risks [6, 20, 21].

Overall complication rates were low and did not differ significantly between RYGB and SADI-S, with no meaningful variation in bleeding, marginal ulceration, internal hernia, dumping syndrome, or iron-deficiency anemia. These findings indicate that both procedures share comparable safety profiles when performed in appropriately selected patients.

Severe malnutrition was uncommon in both cohorts, further supporting the long-term safety of these revisional procedures. However, the persistence of micronutrient deficiencies underscores the chronic nutritional risks inherent to malabsorptive procedures. These results highlight the importance of structured postoperative follow-up and strict adherence to supplementation to sustain long-term outcomes after revision [5, 22].

This study demonstrates that RYGB and SADI-S serve complementary roles rather than interchangeable ones in revisional bariatric surgery. SADI-S offers superior long-term weight-loss durability and metabolic benefits, making it particularly suitable for patients with higher-BMI or early post-sleeve gastrectomy failure. In contrast, RYGB offers a clear advantage in managing GERD and is the preferred option for patients presenting with reflux-dominant symptoms [3, 5, 23].

Accordingly, selection of the revisional procedure should be individualized, integrating factors such as baseline BMI, presence of GERD, nutritional risk, and the patient’s capacity for long-term follow-up. Shared decision-making between the surgeon and the patient remains essential for optimizing outcomes and minimizing postoperative complications [16, 22].

Drs. Asaad Salama, Abdelwahed Yahmadi, Hamzah El Baba, Jawher Baazaoui, Khadija Gibreal, Mohamed Bougmiza and Mohammed Al Kuwari have no conflicts of interest or financial ties to disclose.

The institutional review board of Hamad Medical Corporation (HMC) had granted ethical approval for this retrospective study, and the study's conduct followed the principles of the Declaration of Helsinki. Since this was a retrospective review of existing records, individual informed consent was no longer required.