1. INTRODUCTION

Morbid obesity is a global chronic disease affecting 13% of people worldwide. Weight loss surgery has been proven to be effective in addressing this chronic disease and its associated comorbidities. In 2016, over 200,000 procedures were performed in the United States, and the volume continues to grow. Cases analyzed between 2015 and 2018 indicate an overall growth rate of 21.9%. The most common surgeries performed in the United States are Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), and biliopancreatic diversion with duodenal switch (BPD/DS). Estimated mean weight loss is 33% of the initial body weight. Unfortunately, it is estimated that up to 25% of patients will have weight regain after primary surgery. Weight regains or recidivism has emerged as a clinical entity and important public health issue given its association with re-emergence of obesity related comorbidities, worsening quality of life, and increased healthcare costs. With the increased number of primary bariatric surgery performed worldwide, revisional surgery has also increased, and it has been shown to be the fastest-growing category of bariatric procedures, currently representing 7 to 15% of all bariatric operations and long-term rates of revisional surgery have been estimated to be as high as 56%.

2. CAUSES

Weight regain is estimated in up to 25% of patients following primary bariatric surgery. In addition, it is estimated that more than 80% of the weight regain happens within the first 6 years following primary surgery. A major factor contributing to weight regain is lack of adherence to recommended followup visits, observed in approximately 60% of patients 4 years after primary surgery. The etiology of weight regain has been attributed to:

• Noncompliance with dietary recommendations.

• Hormonal/metabolic imbalance.

• Mental health.

• Physical inactivity.

• Anatomic/surgical factors.

• Medications.

3. PREOPERATIVE EVALUATION

A multidisciplinary evaluation is essential prior to recommending revisional surgery to patients presenting with weight gain. As with primary surgery, a nutritional evaluation, behavioral/psychological assessment, and endoscopic and contrast series studies should be obtained. The latter will not only aid in establishing an anatomic etiology for weight regain if present, but it will also aid in choosing the type of revisional surgery.

4. SELECTING THE TYPE OF REVISIONAL SURGERY

There are several revisional procedures following primary bariatric surgery. The choice of revisional surgery is tailored according to initial surgery, cause of failure, and surgeon’s experience. Multiple revisional surgeries have been described for all primary bariatric surgeries, but no standardized guidelines have been established. In June 2019, 70 experts from 27 countries formed a committee and created the first consensus on revisional bariatric surgery. An agreement of 70% or more was considered consensus. Consensus was achieved in several points including but not limited to:

(1) RBS is justified in some patients;

(2) RBS is more technically challenging than the respective primary bariatric surgery;

(3) second or third RBS can be justified in some patients;

(4) candidates should undergo a nutritional assessment, psychological evaluation, endoscopy, and a contrast series;

(5) RYGB, one anastomosis gastric bypass (OAGB), and SADI-S are options after gastric banding; and

(6) OAGB, BPD/DS, and SADI-S are options after sleeve gastrectomy. Regarding revision for primary RYGB, the only consensus obtained was lengthening of the biliopancreatic limb as RBS option for RYGB or OAGB.

Roux-En-Y Gastric Bypass

Roux-en-Y gastric bypass is one of the most common weight loss procedures performed worldwide and is considered by many to be the gold standard. Unfortunately, approximately 10–34% of patients experience inadequate weight loss or weight gain and may ultimately require revision. The most common etiology of weight regain is pouch dilation. Other reported etiologies include enlarged gastric pouch greater than 5 cm in diameter, wide gastro-jejunal anastomosis (GJA), anastomosis greater than 1 cm, GJA > 1.5 cm in diameter, dilated GJA greater than or equal to 2 cm, pouch >30 mL, pouch dilation >120 mL, weight recidivism with or without gastric fistula, gastric fistula, short-limb bypass, and hyperphagic behavior. Multiple revisional surgeries have been described. In a recent systemic review and meta-analysis, distal Roux-en-Y gastric bypass (DRGB) alone showed the highest decrease in BMI at 1-year follow-up versus biliopancreatic diversion with duodenal switch (BPD/DS) or single anastomosis duodeno-ileal bypass and sleeve gastrectomy (SADI-S) at 3-year follow-up. Overall, they found maximal BMI decrease in DRGB alone, followed by BPD/DS or SADI-S, laparoscopic pouch and/or GJA resizing, and endoscopic pouch and/or GJA resizing.

Sleeve Gastrectomy

Sleeve gastrectomy (SG) is currently the most commonly performed bariatric procedure worldwide. Its relatively simple technique and low complication rate contribute to it being preferred over some other procedures. Revision is estimated in up to 30% of cases for multiple etiologies, including weight regain. Loss of restriction is one of the main anatomic factors contributing to weight regain. Although revision to RYGB or DS has been recommended as the standard of care, some studies have described revision with re-sleeve for dilation of the residual stomach as the cause. The overall %EWL following re-sleeve can be up to 57% at 12 months and up to 60% at 20 months. A retrospective study analyzed conversion from SG to either RYGB or SADI for insufficient weight loss or weight regain. Out of 140 patients, 66 patients underwent SG to SADI, and 74 patients underwent SG to RYGB. SADI was found to achieve 8.7%, 12.4%, and 19.4% more total body weight loss at 6, 12, and 24 months compared to RYGB for weight regain alone. RYGB is preferred when symptoms of reflux accompany weight regain. For patients with super morbid obesity and weight regain after SG, in the absence of reflux symptoms, conversion to biliopancreatic diversion with duodenal switch (BPD/DS) is recommended for maximal weight loss, with %EWL ranging from 70 to 80% at 2 years.

5. WEIGHT LOSS FOLLOWING REVISIONAL SURGERY

Weight loss after revisional bariatric surgery leads to significant weight loss in the long term, rates varying per procedure performed. A single-center retrospective study for patients who underwent revisional surgery for weight regain (52.4%) S. Ardila et al. analyzed weight loss at 3-, 6-, 9-, and 12-month intervals. Patients with a primary restrictive procedure and reflux symptoms underwent conversion to either RYGB or BPD/DS and experienced 50–65.3%EWL at 3 months and 50.1–79.1%EWL at 12 months. Patients with initial RYGB underwent GJ revision for pouch or GJ abnormalities. For those without anatomic abnormalities, they underwent conversion to distal bypass. At 3 months, %EWL was 36.6 for GJ revision and 37.5% for distal revision.

6. Complications of Revisional Surgery

Revisional bariatric surgery is complex, is technically demanding, and is therefore associated with higher morbidity and mortality. Compared to primary surgery, revisional surgery has been associated with higher rates of postoperative complications, longer operative times, longer hospital stay, conversion to open surgery, readmission, and unplanned admission to the critical care unit. In comparing primary versus revisional RYGB, revisional surgery was associated with higher rates of leak, hemorrhage, wound infection, stricture, ulcer, perforation, and hernia. A single-center retrospective study analyzed complications after revisional surgeries performed at their center for weight regain between 2012 and 2015. Of 84 patients, 43 presented for weight regain (52.4%). Complications included incarcerated ventral hernia following AGB conversion to SG, anastomotic leak and recurrent intussusception following gastro-jejunostomy revision, and stricture and marginal ulcer following AGB conversion to RYGB . In summary, reported complications of revisional bariatric surgery are:

• Hernia.

• Anastomotic leak.

• Stricture.

• Marginal ulcer.

• Wound infection.

• Hemorrhage.

• Perforation.

• Obstruction.

Conclusion

Weight regain after primary bariatric surgery is multifactorial. It is imperative to establish guidelines for classifying weight gain in order to guide subsequent intervention and thus to aid bariatric teams internationally in the management of this clinical entity. Revisional surgery has been shown to be a successful treatment option for patients presenting with weight gain, with rates of weight loss nearing those seen after primary surgery. Furthermore, the importance of revisional surgery lies in its ability to readdress many of the obesity-related comorbidities which prompted the primary procedure. When indicated, it is important to tailor the type of revisional surgery to each patient. Although Roux-en-Y gastric bypass remains the most common type of revisional surgery after primary surgery of any type, duodenal switch is emerging as the revision procedure of choice for superobese patients and patients with failed sleeve gastrectomy secondary to weight regain in the absence of reflux symptoms.