Laparoscopic sleeve gastrectomy is still relatively new to bariatric surgery and has been widely utilized as a primary procedure for about 10 years. There is a growing body of long-term weight loss data in the literature but the true incidence of inadequate weight loss or weight regain after LSG is still not clear. In a study by Cesana et al., about 5 % of LSG patients required reoperation with a mean follow-up 21.1 ± 9.7 months (range 6–57 months) [47]. In another study, weight regain of 10 kg from nadir was observed in 19.2 %, i.e., in 5 of the 26 patients during the 5 year follow-up. In the weight regain group, the first year %EWL was comparable to the adequate weight loss group, however the %EWL significantly decreased by the second year in the weight regain group [48]. Like RYGB, the etiology of weight regain after LSG is multifactorial and likely involves anatomic, behavioral, socioeconomic, and psychological components. There are currently few published data that can help identify the right patient for the right bariatric operation, so bariatric surgeons rely on experience, clinical judgment, and patient preference to drive these decisions.

Dilation of the gastric lumen, particularly the gastric fundus, is a common imaging finding in patients with weight regain after LSG. This may be attributed to a lack of adequate calibration at the time of the primary procedure or a natural process of stomach tissue to dilate and become more compliant over time. Patients’ behavioral issues, eating habits, and lack of adherence to the post-surgical diet recommendations may also contribute to this problem [47].

As with RYGB, some patients may benefit from continued medical therapy after LSG. While hunger often disappears for several months after LSG, it inevitably returns and some patients may benefit from medication to control appetite long-term. With a variety of FDA-approved medication for the treatment of obesity available in the USA, these may play an important adjunctive role in the long-term management of some sleeve gastrectomy patients. Further research is necessary to better define the role of medical therapy for patients with IWL or weight regain after sleeve.

A subset of patients with IWL after sleeve gastrectomy may benefit from additional surgical therapy if their weight loss or comorbidity improvement is suboptimal. In a recently published report by Sieber et al., 8 of 68 patients (11.8 %) underwent reoperative surgery due to IWL after sleeve gastrectomy [49]. However, similar to any bariatric procedure, the patient must be evaluated by a multidisciplinary team to determine the cause of weight regain. Surgical options include placement of an adjustable band over the proximal sleeve, re-sleeve gastrectomy (corrective), or conversion to gastric bypass or duodenal switch.

In one study of patients who had a LSG over a 60 French Bougie , placement of an adjustable band due to inadequate weight loss after sleeve gastrectomy resulted in a 78 lb weight loss within 9 months, corresponding to an EWL of 57 % [50]. Overall, though, there are not strong data to support this approach and it is not commonly used.

In a study from Italy, 11 of 201 patients (5.4 %) who regained weight after laparoscopic sleeve gastrectomy underwent laparoscopic re-sleeve gastrectomy with a significant decrease in mean BMI and increase in mean percentage of EWL at 1 year follow-up [47]. Rebibo et al. compared 15 patients who underwent re-sleeve gastrectomy to 30 patients who underwent primary sleeve gastrectomy, and the leak rate for the former group was 13 % (2/15), with less weight loss [51]. Dapri et al. reported a leak in one of seven patients who underwent re-sleeve gastrectomy [52]. However, two series of patients who underwent re-sleeve gastrectomy report no post-procedural leaks [53, 54]. This approach is typically reserved for patients with a dilated sleeve or fundus who refuse conversion to a bypass procedure.

In a study from Austria, 8 out of 73 patients underwent conversion procedure from a laparoscopic sleeve gastrectomy to laparoscopic Roux-en-y gastric bypass (five of the eight were for weight regain). None of these five patients were found to have significant sleeve dilatation. After conversion, a mean weight reduction of 15.2 ± 8 kg (range, 6–25 kg) was achieved within a follow-up from 1 to 52 months [55]. In a group of high risk, high BMI patients, Cottam et al. showed that a second stage RYGB can result in continued weight loss after LSG. One hundred twenty-six patients with mean BMI of 65 underwent LSG with an overall EWL of 46 % at 1 year. Thirty-six patients underwent a conversion procedure to RYGB 1 year after the LSG. That subgroup of patients had a mean BMI of 49 at the time of the conversion and this decreased to a mean BMI of 39 six months after conversion to RYGB with continued improvement in comorbidity status [56]. This study demonstrated the utility of LSG as a risk management strategy in high BMI patients. On the other hand, there will be a subset of these patients who can maintain long-term weight loss after LSG. In a long-term follow-up study of the same patient group, Eid et al. showed that 69 of those patients who did not return for the second stage bypass procedure were able to maintain 48 % EWL and good comorbidity improvement 6–8 years after LSG [57].

These studies highlight why the sleeve gastrectomy has become so popular: It is an effective primary operation but leaves the surgeon several safe and effective options for conversion for patients who do not achieve sufficient weight loss or have weight regain over time.

In a study by Carmeli et al., 19 patients underwent a conversion procedure after sleeve gastrectomy due to IWL (nine underwent duodenal switch and ten underwent gastric bypass). Duodenal switch yields a greater weight loss than gastric bypass, but both are feasible and effective conversion procedures after failed sleeve gastrectomy [58]. The two major advantages of duodenal switch as the conversion procedure are the avoidance of entrance into the area of scarred stomach, and revisability of the malabsorptive component (altering common channel length). The same group from Israel favored gastric bypass as the conversion procedure compared to duodenal switch if the patient had a high operative risk, vitamin deficiency , prior small bowel resection, improvement in diabetes and hypertension after sleeve gastrectomy, or BMI less than 50 prior to the sleeve gastrectomy [58].