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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 1  |  Issue : 1  |  Page : 49-54

Revision of Roux-en-Y-Gastric bypass – Our experience in Indian patients


1 Department of Minimal Access, GI and Bariatric Surgery, HCMCT Manipal Hospital, New Delhi, India
2 General and Liver Transplant Anesthesia, Liver Critical Care, HCMCT Manipal Hospital, New Delhi, India

Date of Submission20-Dec-2021
Date of Acceptance23-Mar-2022
Date of Web Publication07-Apr-2022

Correspondence Address:
Dr. Randeep Wadhawan
Department of Minimal Access, Bariatric and GI Surgery, HCMCT Manipal Hospital Sector 6, Dwarka, New Delhi - 110 075
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jbs.jbs_11_21

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  Abstract 


Background: The indications for revision bariatric surgery include inadequate weight loss, weight regain, failure to resolve comorbidities, and complications associated with primary surgery. Objectives: The objective is to evaluate the outcome of revision of Roux-en-Y gastric bypass (RYGB) and compare the efficacy of different revision procedures for weight regain, resolution of comorbidities, and complications, if any. Methods: Revision cases performed between May 2017 and April 2021 were included. The analysis of collected data was carried out for weight loss, resolution of comorbidities, and adverse outcomes. Results: Twenty three revision procedures were performed. Two patients were lost to follow-up. The overall complication and reoperation rates were 14.29% and 4.76%, respectively. The follow-up duration was at 6, 12, and 36 months. Twenty-one (91.3%) patients completed 6-month, 18 (78.3%) 12-month, and nine (39.1%) completed 36-month follow-up. The mean postoperative body-mass index at 6, 12, 36 months were 33.07+/−4.15, 33.11+/−4.05, 34.5 ± 8.81, respectively. The mean %excess weight loss (EWL) at 6, 12, 36 months were 39.47+/−13.76, 43.70+/−13.70, 41.14+/−8.48%, respectively. The patients were divided into three groups. Group A - lengthening of biliopancreatic limb (BPL) by 100 cm (n = 6); Group B - placement of ring with a diameter of 7.5 cm in addition to BPL lengthening (n = 12); and Group C - pouch trimming with BPL lengthening by 100 cm (n = 3). %EWL at 6 months was 31.86, 47.69, and 53.49, in Groups A, B, and C, respectively. Similar trends in %EWL were observed in three groups at 12 and 36 months. Conclusion: Revision bariatric surgeries are complex procedures. In our study, banded RYGB with BPL lengthening had better outcomes, though a statistical significance could not be established due to the small sample size and retrospective nature of the study.

Keywords: Gastric band, gastric bypass revision, gastric bypass, gastric pouch trimming, laparoscopy, revision bariatric surgery, roux-en-Y-gastric bypass


How to cite this article:
Verma N, Wadhawan R, Sehgal L, Veetil DK, Gupta M. Revision of Roux-en-Y-Gastric bypass – Our experience in Indian patients. J Bariatr Surg 2022;1:49-54

How to cite this URL:
Verma N, Wadhawan R, Sehgal L, Veetil DK, Gupta M. Revision of Roux-en-Y-Gastric bypass – Our experience in Indian patients. J Bariatr Surg [serial online] 2022 [cited 2022 Sep 24];1:49-54. Available from: http://www.jbsonline.org/text.asp?2022/1/1/49/342731




  Introduction Top


Bariatric surgery has been shown to be most effective in achieving sustained weight loss and improving comorbidities in morbidly obese patients. The success of bariatric surgery is defined as ≥50% excess weight loss (EWL) associated with the resolution of obesity-related comorbidities.[1],[2] The failure after bariatric surgery is defined as achieving or maintaining <50% EWL over 18–24 months, or a body mass index (BMI) of >35 kg/m2. A 10-year follow-up of patients who underwent Roux-en-Y-gastric bypass (RYGB) revealed a long-term failure rate of 20.4% in morbidly obese patients and 34.9% in extreme obese (BMI >50 kg/m2) patients and a revision rate of 4.5%.[1],[3],[4],[5]

Several authors have published the results of primary bariatric procedures. However, studies addressing the superior revision surgery after an unsuccessful primary RYGB remain limited. Hence, it is necessary to establish a strategy to guide the surgeons in the decision-making process after an unsuccessful primary surgery. Inadequate weight loss is the most common indication for a revision bariatric surgery after the primary RYGB. Procedure options include trimming the large gastric pouch, lengthening of the Roux limb, lengthening of the biliopancreatic limb (BPL), placement of a band around stomach pouch, endoluminal procedures, and conversion to duodenal switch (DS) operation. Correction of the gastrogastric fistula may be required as this can also be the reason for insufficient weight loss or weight regain. Revision procedure for an unsuccessful primary RYGB is technically challenging as anatomical planes get distorted after the primary surgery. Revision bariatric surgery has been associated with higher rates of complications and questionable efficacy when compared with primary operations, so it should be performed at a high volume center with an experienced surgeon.[6] We hereby share our experience of the revision of RYGB.


  Methods Top


We retrospectively analyzed our prospectively maintained data of revision of RYGB from May 2017 to April 2021. The patient's demographics, weight, and BMI at the time of the revision, types of initial and revision operations, indication for revision, surgical outcomes, and follow-up data were retrospectively analyzed. All the patients were followed up in the outpatient department and were contacted telephonically to collect and maintain the database.

All patients underwent a thorough preoperative evaluation before being posted for revision surgery. A detailed history was taken regarding weight-loss progress after primary bariatric surgery, dietary habits, changes in comorbidities, and psychosocial factors. These patients presented to us with weight regain and were given a trial of diet and lifestyle changes under the supervision of a nutritionist and the surgical team. This included a 1000–1200Kcal diet with an average of 40–45 min of daily exercise. However, they did not lose significant weight hence were considered for revision surgery. They were given a low-calorie liquid diet starting 1 week before surgery. The psychologist counseled all patients. In addition, all the patients underwent an upper gastrointestinal endoscopy (UGIE) to evaluate the pouch, stoma, and evidence of a marginal ulcer and a contrast-enhanced computed tomography scan of the whole abdomen (CECT) to evaluate the anatomy.

Operative procedures

All the procedures were performed via the laparoscopic approach by a single surgeon with experience in primary and revision bariatric procedures. The patients were divided into three groups based on the type of revision surgery performed.

  • Group A: Lengthening of BPL by 100 cm was done in patients with normal UGIE and CECT scans
  • Group B: Placement of a ring with a diameter of 7.5 cm over the stomach pouch in patients with a dilated gastric pouch on CECT scan along with lengthening BPL by 100 cm
  • Group C: Trimming of the Gastric pouch with revision of gastrojejunostomy in addition to lengthening of BPL by 100 cm. This was performed in patients diagnosed with marginal ulcer (ulcer at the gastrojejunal anastomoses) on UGIE.


BPL lengthening was done to increase malabsorption and weight loss. The selection of the staple loads depended on the condition of the gastric wall. In general, a closed staple height of at least 1.8 mm or more was chosen because of the thickened gastric wall. Anastomotic and staple-line leakage were assessed with methylene blue dye in all patients as a protocol. The mesenteric defect was closed to prevent internal hernia.

Postoperative management and follow-up

Oral intake was initiated on the first postoperative day. After achieving adequate oral intake, pain control, and ambulation without difficulty, the patients were discharged.

The postoperative nutritional regimen consisted of a liquid diet for the first 2 weeks with gradual increases in food texture. Patients returned to the outpatient clinic 1 week after the surgery and then at 3, 6, and 12 months for the first postoperative year to monitor weight loss, appetite, dysphagia, food intolerance, eating behavior, comorbidity status, and the presence of any complications or micronutrient deficiency. Subsequently, the follow-up is advised every 12 months. Telephonic communication was also used to monitor patients who could not visit the outpatient clinic. Inadequate weight loss was defined as percentage of (%EWL) <50% or BMI of 35 kg/m2 and over at 1 year or more after the surgery.[3]

Statistical analysis

Microsoft Excel™ was used for the data analysis. Data are presented as median (interquartile range) for continuous variables and frequency percentages for categorical variables. The ideal body weight of each patient was estimated based on the formula that corresponds to the midpoint of the medium frame of the Metropolitan tables.[7] The degree of weight loss was assessed with %EWL and Excess BMI Loss (%EBMIL), which were calculated using the following formulas:[7]

  • %EWL = preoperative weight − current weight/preoperative weight − ideal weight ×100
  • %EBMIL = preoperative BMI − current BMI/preoperative BMI − 25 × 100.



  Results Top


Twenty-three revision surgeries were performed between May 2017 and April 2021. Two patients were lost to follow-up; hence, they were excluded from the study. The patients' clinical characteristics before revision surgery are shown in [Table 1]. The majority of patients were females (18/21). Fifteen patients (71.4%) had undergone primary RYGB elsewhere. The mean time interval from the previous bariatric surgery to revision surgery was 65.33+/−33.53 months, and the mean BMI at the time of revision was 39.49+/−5.68 kg/m2.
Table 1: Prerevision baseline characteristics

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The most common primary indication for revision surgery was inadequate weight loss after primary surgery (71.4%) [Table 2]. Other significant indications were uncontrolled Type 2 diabetes mellitus and inadequate weight loss. Detailed flow of the revision procedures following an unsuccessful primary RYGB are depicted in [Table 3].
Table 2: Indications for revision bariatric surgery

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Table 3: Type of revision procedures after Roux-en-Y gastric bypass

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All revision operations were successfully performed through a laparoscopic approach.

  • Group A: Lengthening of BPL was done in 12/21 patients (57.1%)
  • Group B: Ring placement over the stomach pouch and lengthening of BPL was done in 6 patients 28.57%
  • Group C: Trimming of the Gastric pouch with revision of gastrojejunostomy in addition to lengthening of BPL was done in 3/21 patients 14.28%.


The average hospital stay was 2.29+/−0.46 days, and the mean operative time was 93.57+/-32.29 min. No surgical mortality was observed in our series. The mean BMI decreased from 39.49+/−5.68 kg/m2 to 33.07+/−4.15 kg/m2 at a follow-up period of 6 months after revision. The %EWL and %EBMIL were 39.47+/−13.8 and 45.89+/−16.2%, respectively, at 6 months. One patient developed obstruction after revision surgery. Diagnostic laparoscopy was done, and an additional jejunojejunal anastomosis was done 10 cm proximal to the previous jejunojejunostomy. Two patients developed postoperative nausea and vomiting, which were managed conservatively. Short-term outcomes of revision surgery are summarized in [Table 4].
Table 4: Short-term surgical outcomes of revision surgery

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Eighteen patients (85.71%) had completed at least 12 months of follow-up. The mean BMI was 33.11+/−4.05 kg/m2 at 12 months. The %EWL and %EBMIL were 43.70+/−13.70% and 51.44+/−13.43%, respectively. Nine patients (42.86%) completed 36 months of follow-up. The mean BMI was noted to be 34.5+/−8.81 kg/m2. The %EWL and %EBMIL were 41.14 ± 8.17% and 44.93 ± 8.17%, respectively [Table 5]. Fifty percent of patients had remission from diabetes within 6 months. The remaining 50% of diabetic patients on insulin were successfully switched to oral hypoglycemic agents. 66.7% of patients had remission from diabetes at the end of 36 months. We calculated remission when the blood sugar F <110 mg%, HBA1C <6.4 with no medication.
Table 5: Weight parameters following the revision surgeries

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Improvement in blood pressure control was observed in 50% of patients at 6 months and 100% at 12 months. Improvement was also noticed from hypothyroidism, obstructive sleep apnea, and joint pain within 6 months. Improvement was calculated when the parameters were normal with reduced medication. One patient had chronic kidney disease. Her average serum creatinine level decreased at 6 months after revision surgery [Table 6].
Table 6: Comorbidities resolution after revision surgery

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Increased %EWL and %EBMIL were observed in Groups B and C compared to Group A [Table 7].
Table 7: Outcomes after three different revision procedures

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In our group of patients, no band-related complications were observed in patients who had undergone banded RYGB.


  Discussion Top


The number of primary bariatric procedures performed has increased over time; hence, the number of patients undergoing revision procedures continues to rise. Aside from revision procedures to manage early surgical complications, many patients require a redo operation months or years after the primary surgery for various reasons, including insufficient weight loss or weight regain, delayed complications associated with implants, or other intolerable side effects. Revision bariatric surgery comprises 5%–15% of total cases of all bariatric surgery.[7],[8],[9],[10] The rate of revision surgery is 20%–60% after adjustable gastric banding,[11],[12],[13],[14],[15],[16] 9%–17% after RYGB[11],[15],[17],[18] and 9%–11% after sleeve gastrectomy.[19],[20]

Revision RYGB accounted for 5.72% (23/402) of all bariatric surgeries at the authors' center during the study. A total of 71.4% (15/21 patients) of our patients undergoing revision surgery were referred to us from outside clinics with primary surgery done elsewhere. UGIE and CECT scans may be considered as preoperative investigations before revising RYGB. The volumetry or size of the stomach pouch would be an indication for the trimming of the pouch and placement of a ring around the pouch.

Different types of primary surgeries lead to different reasons for conversion.[20] In the present case series, insufficient weight loss or regain of weight was the most frequent reason for revision. Poorly controlled Type 2 diabetes mellitus and inadequate weight loss were the second most common indication for revision among them. However, these indications are not entirely independent from each other, and many patients have a combination of these complaints.

The re-operative procedure of choice should depend on several factors, including patient history and intraoperative findings. The commonly advocated fundamental principle of revision surgery is to convert a purely restrictive procedure to include malabsorptive components.[21] Revision bariatric surgeries are complex and technically demanding. It is generally associated with a higher risk of postoperative complications than primary procedures with a perioperative morbidity rate of between 19% and 50%.[10],[22],[23],[24] With the advancement of laparoscopic surgical skills, several studies have recently demonstrated that laparoscopic revision can be performed safely by well-trained and highly experienced bariatric surgeons in specialized bariatric centers.[17],[25] The complication rates for laparoscopic revision are reported between 14.3% and 46.3% with conversion to laparotomy in 3%–27.8%.[17],[25],[26] Trimming of gastric pouch and revising the gastrojejunostomy, revision with a gastric band, increasing BPL, revision to biliopancreatic diversion/DS, and revision to endoluminal procedures (i.e., stomaphyx) can be the options after a previous RYGB. All these revision procedures result in sustained weight loss, with an acceptable rate of complications.[27]

Our results showed a perioperative significant complication rate of 4.76%. One patient developed obstruction after revision surgery on a postoperative day 5. The patient was readmitted, and a diagnostic laparoscopy was done. Intraoperative findings revealed a kink at jejunojejunostomy site caused by a suture, leading to dilation of the BPL along with gastric pouch dilatation, as shown in [Figure 1]. Adhesiolysis was done along with an additional jejunojejunostomy constructed 10 cm proximal to the previous one [Figure 2]. The patient recovered well and was discharged on the 4th postoperative day.
Figure 1: Obstruction due to kink caused by suture at jejuno-jejunostomy in revision case

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Figure 2: Revision of jejuno-jejunostomy 10 cm proximal to obstructed anastomosis

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In our subset of Indian patients, we increased the BPL by 100 cm while keeping the common channel at 400–500 cm. We did not decrease the common channel <400 cm to avoid severe malabsorption and nutritional deficiencies postoperatively [Figure 3]. The mesenteric defect was closed with nonabsorbable barbed suture to prevent internal hernia [Figure 4]. In patients with dilated gastric pouch, we trimmed the gastric pouch and placed a ring of 7.5 cm size around the pouch to prevent weight regain [Figure 5]. In our study, three patients were diagnosed with margin ulcer at the gastrojejunal anastomosis on UGIE with a dilated gastric pouch, so pouch trimming revision of gastrojejunostomy and increasing the BPL was done. The addition of restrictive components and mal-absorption results in more sustained %EWL and %EBMIL than mal-absorption only. In our study, the group having ring placement and gastric pouch revision in addition to BP limb lengthening showed more% EWL and %EBMIL as compared to only BP limb lengthening. However, the sample size is small. Hence, more data are required to compare these three procedures. Moreover, indications of these procedures can be different, so the comparison may not be feasible.
Figure 3: Increasing biliopancreatic limb by 100 cm

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Figure 4: Closure of mesenteric defects to prevent internal herniation

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Figure 5: Band placement as revision procedure after previous Roux-en-Y gastric bypass

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The laparoscopic approach could be safe for revision with acceptable risks. Open surgery may be technically more challenging in morbidly obese patients because it would be difficult to approach the deep-seated intra-abdominal organs and secure an appropriate surgical view because of excessive fat tissues. The laparoscopic approach provides a better vision with a close view facilitating more precise dissection. However, it may be challenging to identify the original anatomy as adhesions may result in anatomic distortion. Adhesiolysis may be associated with bleeding, interfering with surgical vision and accurate dissection. It could increase the risk of postoperative complications; hence, revision procedures should be performed by an experienced surgeon at a high-volume center.

There are a few limitations of the present study:

This was a retrospective study from a single institution, and the number of enrolled patients is small. The anthropometric data of the enrolled patients before the primary surgery were often missing, so the efficacy of revision surgery compared with the primary operation could not be demonstrated. The follow-up for nutritional deficiencies was done; however, the data were not maintained. The follow-up duration is short, and the collection of long-term results is still needed.


  Conclusion Top


Revision RYGB using the laparoscopic approach can be successfully performed with an acceptable risk of postoperative morbidity and satisfactory short-term weight loss. Increasing the BPL by 100 cm seems to be an optimal option in terms of %EWL and %EBMIL while keeping the common channel at least 400–500 cm. In addition, pouch trimming with placement of a ring may be considered in case of pouch dilatation. In our study, banded RYGB with BPL lengthening had better outcomes, though a statistical significance could not be established due to small sample size and retrospective nature of the study. However, long-term follow-up is required to compare outcomes and device a tailored strategy for type of revision surgery required as per indications.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Bessler M, Daud A, DiGiorgi MF, Olivero-Rivera L, Davis D. Adjustable gastric banding as a revisional bariatric procedure after failed gastric bypass. Obes Surg 2005;15:1443-8.  Back to cited text no. 1
    
2.
Gobble RM, Parikh MS, Greives MR, Ren CJ, Fielding GA. Gastric banding as a salvage procedure for patients with weight loss failure after Roux-en-Y gastric bypass. Surg Endosc 2008;22:1019-22.  Back to cited text no. 2
    
3.
Fobi MA, Lee H, Igwe D Jr., Felahy B, James E, Stanczyk M, et al. Revision of failed gastric bypass to distal Roux-en-Y gastric bypass: A review of 65 cases. Obes Surg 2001;11:190-5.  Back to cited text no. 3
    
4.
Parikh M, Pomp A, Gagner M. Laparoscopic conversion of failed gastric bypass to duodenal switch: Technical considerations and preliminary outcomes. Surg Obes Relat Dis 2007;3:611-8.  Back to cited text no. 4
    
5.
Irani K, Youn HA, Ren-Fielding CJ, Fielding GA, Kurian M. Midterm results for gastric banding as salvage procedure for patients with weight loss failure after Roux-en-Y gastric bypass. Surg Obes Relat Dis 2011;7:219-24.  Back to cited text no. 5
    
6.
Zhang L, Tan WH, Chang R, Eagon JC. Perioperative risk and complications of revisional bariatric surgery compared to primary Roux-en-Y gastric bypass. Surg Endosc 2015;29:1316-20.  Back to cited text no. 6
    
7.
Deitel M, Gawdat K, Melissas J. Reporting weight loss 2007. Obes Surg 2007;17:565-8.  Back to cited text no. 7
    
8.
Behrns KE, Smith CD, Kelly KA, Sarr MG. Reoperative bariatric surgery. Lessons learned to improve patient selection and results. Ann Surg 1993;218:646-53.  Back to cited text no. 8
    
9.
Radtka JF 3rd, Puleo FJ, Wang L, Cooney RN. Revisional bariatric surgery: Who, what, where, and when? Surg Obes Relat Dis 2010;6:635-42.  Back to cited text no. 9
    
10.
Spyropoulos C, Kehagias I, Panagiotopoulos S, Mead N, Kalfarentzos F. Revisional bariatric surgery: 13-year experience from a tertiary institution. Arch Surg 2010;145:173-7.  Back to cited text no. 10
    
11.
Sjöström L, Narbro K, Sjöström CD, Karason K, Larsson B, Wedel H, et al. Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl J Med 2007;357:741-52.  Back to cited text no. 11
    
12.
Boza C, Gamboa C, Perez G, Crovari F, Escalona A, Pimentel F, et al. Laparoscopic adjustable gastric banding (LAGB): Surgical results and 5-year follow-up. Surg Endosc 2011;25:292-7.  Back to cited text no. 12
    
13.
Van Nieuwenhove Y, Ceelen W, Stockman A, Vanommeslaeghe H, Snoeck E, Van Renterghem K, et al. Long-term results of a prospective study on laparoscopic adjustable gastric banding for morbid obesity. Obes Surg 2011;21:582-7.  Back to cited text no. 13
    
14.
Himpens J, Cadière GB, Bazi M, Vouche M, Cadière B, Dapri G. Long-term outcomes of laparoscopic adjustable gastric banding. Arch Surg 2011;146:802-7.  Back to cited text no. 14
    
15.
Romy S, Donadini A, Giusti V, Suter M. Roux-en-Y gastric bypass vs. gastric banding for morbid obesity: A case-matched study of 442 patients. Arch Surg 2012;147:460-6.  Back to cited text no. 15
    
16.
O'Brien PE, MacDonald L, Anderson M, Brennan L, Brown WA. Long-term outcomes after bariatric surgery: Fifteen-year follow-up of adjustable gastric banding and a systematic review of the bariatric surgical literature. Ann Surg 2013;257:87-94.  Back to cited text no. 16
    
17.
Higa K, Ho T, Tercero F, Yunus T, Boone KB. Laparoscopic Roux-en-Y gastric bypass: 10-year follow-up. Surg Obes Relat Dis 2011;7:516-25.  Back to cited text no. 17
    
18.
Himpens J, Coromina L, Verbrugghe A, Cadière GB. Outcomes of revisional procedures for insufficient weight loss or weight regain after Roux-en-Y gastric bypass. Obes Surg 2012;22:1746-54.  Back to cited text no. 18
    
19.
Weiner RA, Theodoridou S, Weiner S. Failure of laparoscopic sleeve gastrectomy – Further procedure? Obes Facts 2011;4 Suppl 1:42-6.  Back to cited text no. 19
    
20.
van Rutte PW, Smulders JF, de Zoete JP, Nienhuijs SW. Indications and short-term outcomes of revisional surgery after failed or complicated sleeve gastrectomy. Obes Surg 2012;22:1903-8.  Back to cited text no. 20
    
21.
Zundel N, Hernandez JD. Revisional surgery after restrictive procedures for morbid obesity. Surg Laparosc Endosc Percutan Tech 2010;20:338-43.  Back to cited text no. 21
    
22.
Schwartz RW, Strodel WE, Simpson WS, Griffen WO Jr. Gastric bypass revision: Lessons learned from 920 cases. Surgery 1988;104:806-12.  Back to cited text no. 22
    
23.
Owens BM, Owens ML, Hill CW. Effect of revisional bariatric surgery on weight loss and frequency of complications. Obes Surg 1996;6:479-84.  Back to cited text no. 23
    
24.
Sugerman HJ, Kellum JM Jr., DeMaria EJ, Reines HD. Conversion of failed or complicated vertical banded gastroplasty to gastric bypass in morbid obesity. Am J Surg 1996;171:263-9.  Back to cited text no. 24
    
25.
Gagner M, Gentileschi P, de Csepel J, Kini S, Patterson E, Inabnet WB, et al. Laparoscopic reoperative bariatric surgery: Experience from 27 consecutive patients. Obes Surg 2002;12:254-60.  Back to cited text no. 25
    
26.
Tran TT, Pauli E, Lyn-Sue JR, Haluck R, Rogers AM. Revisional weight loss surgery after failed laparoscopic gastric banding: An institutional experience. Surg Endosc 2013;27:4087-93.  Back to cited text no. 26
    
27.
Lim CS, Liew V, Talbot ML, Jorgensen JO, Loi KW. Revisional bariatric surgery. Obes Surg 2009;19:827-32.  Back to cited text no. 27
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]



 

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