Reoperation risk following the first operation for internal herniation in patients with laparoscopic Roux-en-Y gastric bypass

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Original article Reoperation risk following the first operation for internal herniation in patients with laparoscopic Roux-en-Y gastric bypass S. Danshøj Kristensen 1,3,L.Naver 1,P.Jess 1 and A. K. Floyd 2,3 Departments of Surgery, 1 Koege Hospital, Koege, and 2 Holbæk Hospital, Holbæk, and 3 Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark Correspondence to: Dr S. Danshøj Kristensen, Department of Surgery, Koege Hospital, Lykkebaekvej 1, 4600 Koege, Denmark (e-mail: sark@regionsjaelland.dk) Background: Laparoscopic Roux-en-Y gastric bypass (LRYGB) is the most commonly used surgical procedure in the treatment of morbid obesity in Denmark. Internal herniation (IH) and intermittent internal herniation (IIH) are probably the most common late complications in patients with LRYGB. The aim of this study was to investigate a possible increased risk of subsequent operations after an initial IH or IIH event. Methods: This long-term follow-up study of patients who had surgery for an initial IH or IIH event in 2006 2011, based on the Danish National Patient Registry (NPR), was performed to 2013. During this period, mesenteric defects were not closed routinely during LRYGB. Results: Data were retrieved from 12 221 patients with LRYGB from the NPR. A total of 383 patients had surgery for an initial IH or IIH event. Some 102 patients (26 6 (95 per cent c.i. 22 5to31 3) per cent) had a second operation. Twenty-seven (26 5 (18 9 to 35 8) per cent) of these 102 patients had a third operation, and five (19 (8 to 37) per cent) of the 27 had a fourth operation. Of the 383 patients diagnosed with an initial IH or IIH event, 72 (18 8 per cent) had a second IH/IIH event, 14 (3 7 per cent) had a third event, and three (0 8 per cent) a fourth event requiring surgery. Conclusion: Patients who have surgery for IH or IIH have a substantial risk of needing further operations. Paper accepted 7 March 2016 Published online 23 June 2016 in Wiley Online Library (www.bjs.co.uk). DOI: 10.1002/bjs.10184 Introduction Laparoscopic Roux-en-Y gastric bypass (LRYGB) is one of the most common operations for severely obese patients in Denmark 1. Internal herniation (IH) or intermittent internal herniation (IIH) are common complications after LRYGB 2. In a recent study, the authors 3 found a cumulative 5-year incidence of IH/IIH of 4 per cent in the Danish LRYGB population. Recently, some authors 2,4 have indicated an increased risk of further operations after initial surgery for IH/IIH. However, there are no long-term follow-up studies of patients who have been operated on for IH/IIH with regard to the frequency of possible subsequent operations. This study investigated all operations following initial surgery for IH/IIH in the Danish study population 3 based on the Danish National Patient Registry (NPR) 1. Methods A long-term follow-up study of patients with LRYGB who had surgery for an initial IH or IIH event between 2006 and 2011 was performed to 2013. All operation charts based on the following operation codes from ICD-10 5 were collected: KJAG* (operations for hernia and abdominal wall defects), KJAW* (other operations on the abdominal wall, peritoneum, mesentery and omentum), KJAK* (adhesiolysis and bowel obstruction) and KJFL* (bowel obstruction without adhesions). The study was authorized by the Danish National Board of Health, with approval from the Danish Data Protection Agency (SN-10-2012) and the Regional Research Ethics Committee in the Region of Zealand (RVK Zealand) (1-01-83-0209-12, SJ-284). The study selection process is shown in Fig. 1. All operations and patient charts were revised using a previously proposed classification process 3 in which all registered operations were classified with regard to IH and IIH using the following standard definitions 6, based on operative and radiological findings as well as clinical symptoms, and whether symptoms resolved after closure of the mesenteric defects. IH was defined as herniation of the small bowel 2016 BJS Society Ltd BJS 2016; 103: 1184 1188

Internal herniation following laparoscopic Roux-en-Y gastric bypass 1185 Patients with LRYGB operated on from 2006 to 2011 n = 12221 Patient and operation charts identified from the NPR and validated n = 609 Patients classified with IH/IIH n = 383 Patients having a second operation n = 102 Patients having a third operation n = 27 Patients having a fourth operation n = 5 Patients not classified with IH/IIH n = 226 further surgery n = 281 further surgery n = 75 further surgery n = 22 Fig. 1 Study selection process. LRYGB, laparoscopic Roux-en-Y gastric bypass; IH, internal herniation; IIH, intermittent internal herniation; NPR, Danish National Patient Register through one or both of the mesenteric defects, as shown by CT and/or laparoscopy, requiring reduction of the herniation and closure of the mesenteric defects 3. IIH was defined as recurrent postprandial pain and/or signs of IH on CT. At laparoscopy, the herniation may not be present, suggesting spontaneous reduction. If the postprandial pain disappears after closure of the mesenteric defects in the following 3 months, the diagnosis is considered confirmed 3. Open spaces alone were not considered to be conclusive of IH 3. In addition, data on age, sex, symptoms, time of onset of symptoms, weight loss and reports of available CT scans were registered, as well as details of possible complications during the same hospital stay. In patients with possible recurrent IH or IIH, the approach for the operation was recorded (laparoscopic, open or converted to open surgery). The technique for the closure of mesenteric defects was recorded with regard to the use of absorbable versus non-absorbable sutures or clips. Statistical analysis Non-parametric statistical tests were used; clinical and categorical data were compared with the χ 2 test and continuous data with the Mann Whitney U test. Continuous data are presented as medians with ranges, and frequencies as percentages with 95 per cent confidence intervals (c.i.). The significance level was 5 per cent. Statistical analyses were performed using the statistical software package SPSS version 21 (IBM, Armonk, New York, USA). Results A total of 12 221 patients who had LRYGB surgery from 2006 to 2011 were registered in the NPR. Some 609 of these patients were retrieved from the NPR by cross-linking to operation codes, and all operation charts were validated with regard to IH/IIH. Of the 12 221 patients, 383 (3 1 per cent) had an operation for an initial IH or IIH event, with complete follow-up for up to 7 years (median 38 months). The remaining 226 patients had surgery for other reasons (Fig. 1); 15 were operated on for small bowel obstruction (SBO) not related to IH/IIH, and were classified as having SBO. Of the 383 patients classified with an initial IH/IIH event, 102 (26 6 (95 per cent c.i. 22 5 to31 3) per cent) had a second operation, a median of 8 (range 0 41) months later. Table 1 provides an overview of the reasons for these operations. Twenty-seven (26 5 (18 9 to 35 8) per cent) of these 102 patients had a third operation, with a median time interval of 15 (3 39) months from the second operation. Five (19 (8 to 37) per cent) of these 27 patients had a fourth operation, with a median time interval of 22 (8 42) months from the third operation. The proportions of the initial 383 patients undergoing second, third and fourth operations during follow-up to 2013 were thus 26 6 per cent (102 patients), 7 1 per cent (27 patients) and 1 3 per cent (5 patients) respectively. Of the 383 patients with an initial IH or IIH event, 72 (18 8 per cent) had a second operation for an IH/IIH event, 14 (3 7 per cent) for a third event, and three (0 8per cent) for a fourth IH/IIH event. The suspicion of recurrent IH/IIH was therefore correct for 70 6 per cent (72 of 102) having a second, 52 per cent (14 of 27) having a third, and 60 per cent (3 of 5) having a fourth operation. Some 95 (93 1 per cent) of the 102 operations were done laparoscopically. Table 2 shows symptoms, signs and CT findings for the 72 patients who were classified as having a second IH/IIH event, and for the 30 patients who had surgery for suspicion of IH/IIH but in whom the diagnosis was not confirmed and who were therefore not classified as having IH/IIH.

1186 S. Danshøj Kristensen, L. Naver, P. Jess and A. K. Floyd Table 1 Intraoperative findings of patients who underwent a second, third and fourth operation for internal herniation or intermittent internal herniation Intraoperative findings No. of patients Second operation (n = 102) IH 42 IIH 30 Normal anatomy and closed mesenteric defects 14 Small bowel obstruction owing to adhesions or band 12 Removal of the gallbladder owing to cholecystitis 2 Intussusception of the EEA leading to remodelling of the EEA 1 Endometritis and mesenteric defects closed 1 Third operation (n = 27) IH 8 IIH 6 Normal anatomy and mesenteric defects closed 6 Small bowel obstruction owing to adhesions or band 7 Fourth operation (n = 5) IH 2 IIH 1 Small bowel obstruction because of adhesions 2 IH, internal herniation; IIH, intermittent internal herniation; EEA, enteroenteral anastomosis. Table 2 Clinical symptoms, signs and CT findings in 102 patients who had a second operation IH/IIH (n = 72) No IH/IIH (n = 30) P* Symptoms Upper abdominal pain 66 (92) 22 (73) 0 076 Colicky abdominal pain 55 (76) 19 (63) 0 223 Nausea and/or vomiting 46 (64) 17 (57) 0 406 Constipation 5 (7) 2 (7) 0 859 Signs Peritonitis 1 (1) 0 (0) 0 512 Abdominal CT 47 (65) 20 (67) 0 507 Positive sign of IH 29 of 47 (62) 1 of 20 (5) 0 001 Values in parentheses are percentages. IH, internal herniation; IIH, intermittent internal herniation. *χ 2 test. CT findings Preoperative CT scans of the abdomen were available for 47 (65 per cent) of the 72 patients in the Region of Zealand who had a second IH/IIH event. Twenty-five patients (35 per cent) were operated on with no preoperative CT report. In 29 (62 per cent) of the 47 patients, the following positive signs for IH were found in the CT reports: mesenteric swirl, small bowel behind the superior mesenteric artery, and dilatation of small bowel loops. The remaining 18 patients had none of these CT signs. The positive predictive value of preoperative CT reports with regard to IH/IIH when the above-described signs were listed was 97 per cent, and the negative predictive value 51 per cent. Reoperations owing to complications Of the 102 patients operated on for suspicion of a second IH/IIH event, eight (7 8 per cent) had the operation for complications during the same hospital stay: bleeding (2 patients), abscesses (1), wound dehiscence (1), kinking (1), small bowel adhesions (1), removal of an unspecified foreign body (1), and a planned second-look operation, where all organs were found to be vital with sufficiently closed mesenteric defects (1). Two (7 per cent) of the 27 patients who had a third operation had this surgery during the same hospital stay (intestinal perforation, 1; intra-abdominal abscess, 1). One (20 per cent) of the five patients who had a fourth operation needed this reoperation for stenosis of the enteroenteral anastomosis, which then was reconstructed. Discussion A high frequency of reoperations was found following LRYGB in patients who had an initial IH/IIH event. Recently, both Elms and colleagues 4 and Quezada and co-workers 2 have described the frequency of surgery for SBO in patients with LRYGB where mesenteric defects were closed routinely during the procedure. Elms et al. 4 found a frequency of first operations for SBO of 3 9 per cent (93 of 2395), within a mean interval of 20 9 (range 0 100) months. As for the present patients, all patients in both cohorts 2,4 were operated on with an antecolic LRYGB technique. Some 11 (12 per cent) of the 93 patients in the study by Elms et al. 4 had a second operation for SBO, with a mean time interval of 20 1 (0 52) months, and only one patient needed a third operation for SBO due to adhesions. Quezada et al. 2 found a frequency of 3 1 per cent (84 of 2693) for patients who required a second operation, mostly for acute bowel obstruction, within a mean interval of 13 3 months (range 1 2471 days). In the present study, the frequency of initial IH/IIH after LRYGB was somewhat lower compared with the Elms study 4 at 3 1 per cent, within a median interval of 38 (range 16 87) months 3. However, in these patients mesenteric defects were not closed routinely during LRYGB. In the recently published retrospective study by Al-Mansour and colleagues 7, the frequency of IH was as high as 6 2 per cent. The patients in their cohort were operated on with an antecolic technique, and jejunojejunal mesenteric defects were closed routinely; Petersen s defect was closed only in some patients during some of the study. The median follow-up time was 50 months 7. Elms and co-workers 4 found a somewhat lower frequency of 1 2 per cent during a period in which jejunojejunal mesenteric defects were not closed routinely. These authors 4 reported a frequency of

Internal herniation following laparoscopic Roux-en-Y gastric bypass 1187 2 8 per cent (67 of 2395) for initial operations for SBO not caused by IH. In contrast, in the present study the frequency of SBO was only 0 1 per cent (15 of 12 221) at the first operation after LRYGB. To date, two randomized trials 8,9 have been published. In an American randomized trial 8 including 105 patients, closure of the jejunojejunal mesenteric defect was compared with no closure. Frequencies of subsequent operations for IH were 0 and 1 9 per cent respectively (P = 0 343), and 0 per cent in both cohorts for SBO (P = 1 000), with an average follow-up of 34 months. A large Swedish randomized multicentre study 9 (2507 patients) examined the risk of bowel obstruction in a group of patients in whom mesenteric defects were closed (predominantly with sutures) during LRYGB compared with that in a group without closure. The authors found a higher frequency of operations for SBO (including IH and IIH) during the first year in the closed group (2 2 per cent versus 0 7 per cent in the open group; P = 0 003) 10. However, the risk of operation for SBO increased in the open group 10,11 during the second year of follow-up (4 5 per cent versus 1 9 per cent in the closed group; P < 0 001) 10. In the present study, a relatively high proportion of second operations were for recurrent IH/IIH (18 8 per cent) when mesenteric defects were closed during the initial surgery for IH/IIH. Elms and colleagues 4 described a similar high frequency (3 of 29, 10 per cent) in patients who had a second operation for IH. However, the mean interval of 20 1 (range 0 52) months was somewhat longer than that of 8 (0 41) months) to the second operation in the present study. None of the reported studies provided frequencies for third or fourth operations for IH after LRYGB. Most of the studies do not provide clear definitions for IH or IIH, making comparisons difficult. In addition, many studies had low rates of complete follow-up. Quezada et al. 2 reported follow-up data based on only 3 9 per cent of the patients after 6 years, and Higa and co-workers 12 provided data for 7 per cent of their patients 10 years after LRYGB. Reported case studies 2,12 were based solely on patients with LRYGB in whom mesenteric defects were closed routinely during LRYGB, the only exception being the study of Elms et al. 4, where the jejunojejunal mesenteric defect was not closed during a period of 4 years 7 months within a total study interval of almost 9 years. However, specific data for the subgroup that may be more comparable to the present study population were not provided 4. Many authors 4,7,12 14 recommend non-absorbable sutures for the closure of mesenteric defects to reduce the risk of further IH. It has been argued by others 2,4,7,15,16 that mesenteric defects can open again. In the present study, 18 8 per cent (72 of 383) of the patients had reopened mesenteric defects after an initial closure. Errebo and Sommer 17 argue that a reason for reopening of mesenteric defects may be difficulty in identifying and closing the mesenteric defects (non-closure) correctly during the initial attempt at closure. Although most patients in the present study had surgery in departments with bariatric centres, experienced bariatric surgeons did not operate on all patients. As no specific data on the surgeons were available, further analysis was not possible. There are risks of systematic bias and limitations when using data from a national register compared with prospective controlled studies. Data in the Danish register may be incorrect owing to faulty reporting 1, resulting in underestimation of the true risk of subsequent operations in patients with LRYGB. Furthermore, there was no specific ICD code for the closure of mesenteric defects during the study period, so that mesenteric defects closed during another procedure may not have been registered. The overall positive predictive value of an available CT report was high (97 per cent), but the negative predictive value was low (51 per cent). These findings are supported by those of Obeid and colleagues 18, who reported that nearly 20 per cent of patients with IH had negative findings on CT. However, the results of the present study must be viewed with caution as not all patients had preoperative CT and it was not possible for all CT scans to be reviewed by experienced radiologists, as others have reported 7. Al-Mansour et al. 7 reported that six (17 per cent) of their 36 patients with IH showed no abnormality on the preoperative CT scan (including mesenteric swirl sign, small bowel behind the superior mesenteric artery, dilatation of small bowel loops, mesenteric oedema, free abdominal fluid, mushrooming of the mesentery, and small bowel intussusception). Newer studies 19 21 on sensitivity and specificity for the value of CT have revealed several signs for IH that are probably more accurate than the swirl sign. For instance, compression of the superior mesenteric artery may be a reliable sign of IH in patients with antecolic LRYGB 22. The value of diagnostic laparoscopy in patients with LRYGB and intermittent chronic abdominal pain has been emphasized by Pitt and co-workers 23, as the majority of patients had abnormal findings. However, a more specific classification of clinical symptoms present at admission may help to improve preoperative diagnosis, especially in patients with negative findings on CT. Disclosure The authors declare no conflict of interest.

1188 S. Danshøj Kristensen, L. Naver, P. Jess and A. K. Floyd References 1 Danish National Patient Registry. http://www.sundheds datastyrelsen.dk/da/registre-og-services/om-de-nation ale-sundhedsregistre/sygdomme-laegemidler-og-behan dlinger/landspatientregisteret [accessed 17 February 2016]. 2 Quezada N, León F, Jones A, Varas J, Funke R, Crovari F et al. High frequency of internal hernias after Roux-en-Y gastric bypass. Obes Surg 2015; 25: 615 621. 3 Danshøj Kristensen S, Jess P, Floyd AK, Eller A, Engberg A, Naver L. Internal herniation after laparoscopic antecolic Roux-en-Y gastric bypass: a nationwide Danish study based on the Danish National Patient Register. Surg Obes Relat Dis 2016; 12: 297 303. 4 Elms L, Moon RC, Varnadore S, Teixeira AF, Jawad MA. Causes of small bowel obstruction after Roux-en-Y gastric bypass: a review of 2395 cases at a single institution. Surg Endosc 2014; 28: 1624 1628. 5 World Health Organization. International Classification of Diseases (ICD). http://www.who.int/classifications/icd/en/ [accessed 26 March 2016]. 6 Kristensen SD, Naver L, Jess P, Floyd AK. Effect of closure of the mesenteric defect during laparoscopic gastric bypass and prevention of internal hernia. Dan Med J 2014; 61: A4854. 7 Al-Mansour MR, Mundy R, Canoy JM, Dulaimy K, Kuhn JN, Romanelli J. Internal hernia after laparoscopic antecolic Roux-en-Y gastric bypass. Obes Surg 2015; 25: 2106 2111. 8 Rosas U, Ahmed S, Leva N, Garg T, Rivas H, Lau J et al. Mesenteric defect closure in laparoscopic Roux-en-Y gastric bypass: a randomized controlled trial. Surg Endosc 2015; 29: 2486 2490. 9 Stenberg E, Szabo E, Ågren G, Ottosson J, Marsk R, Lönroth H et al. Closure of mesenteric defects in laparoscopic gastric bypass: a multicentre, randomised, parallel, open-label trial. Lancet 2016; [Epub ahead of print]. 10 Stenberg E, Szabo E, Agren G, Ottosson J, Marsk R, Lönroth H et al. Slitsförslutning vid Laparoskopisk Gastric Bypass. En Randomiserad Klinisk Studie; 2015. http://www. demo.svenskkirurgi.se/documents/abstracts_2015.pdf [accessed 26 March 2016]. 11 Stenberg E, Szabo E, Agren G, Ottosson J, Marsk R, Lönroth H et al. Closing the Mesenteric Defects in Laparoscopic Gastric Bypass. A Randomized Controlled Trial from the Scandinavian Obesity Surgery Registry. Obesity Week 2014, Boston. http://2014.obesityweek.com/wp/uploads/ 2014/10/Tuesday-Abstracts-.pdf [accessed 26 March 2016]. 12 HigaK,HoT,TerceroF,YunusT,BooneKB. Laparoscopic Roux-en-Y gastric bypass: 10-year follow-up. Surg Obes Relat Dis 2011; 7: 516 525. 13 Hwang RF, Swartz DE, Felix EL. Causes of small bowel obstruction after laparoscopic gastric bypass. Surg Endosc 2004; 18: 1631 1635. 14 Onopchenko A. Radiological diagnosis of internal hernia after Roux-en-Y gastric bypass. Obes Surg 2005; 15: 606 611. 15 Iannelli A, Buratti MS, Novellas S, Dahman M, Amor IB, Sejor E et al. Internal hernia as a complication of laparoscopic Roux-en-Y gastric bypass. Obes Surg 2007; 17: 1283 1286. 16 Comeau E, Gagner M, Inabnet WB, Herron DM, Quinn TM, Pomp A. Symptomatic internal hernias after laparoscopic bariatric surgery. Surg Endosc 2005; 19: 34 39. 17 Errebo MB, Sommer T. Leakage and internal herniation are the most common complications after gastric bypass. Dan Med J 2014; 61: A4844. 18 Obeid A, Long J, Kakade M, Clements RH, Stahl R, Grams J. Laparoscopic Roux-en-Y gastric bypass: long term clinical outcomes. Surg Endosc 2012; 26: 3515 3520. 19 Goudsmedt F, Deylgat B, Coenegrachts K, Van De Moortele K, Dillemans B. Internal hernia after laparoscopic Roux-en-Y gastric bypass: a correlation between radiological and operative findings. Obes Surg 2015; 25: 622 627. 20 Iannuccilli JD, Grand D, Murphy BL, Evangelista P, Roye GD, Mayo-Smith W. Sensitivity and specificity of eight CT signs in the preoperative diagnosis of internal mesenteric hernia following Roux-en-Y gastric bypass surgery. Clin Radiol 2009; 64: 373 380. 21 Lockhart ME, Tessler FN, Canon CL, Smith JK, Larrison MC, Fineberg NS et al. Internal hernia after gastric bypass: sensitivity and specificity of seven CT signs with surgical correlation and controls. AJR Am J Roentgenol 2007; 188: 745 750. 22 Maier JF, Floyd AK. Redefining the Mesenteric Swirl Sign (MSS) in the Diagnosis of Internal Herniation (IH) after Roux-en-Y Gastric Bypass (RYGBP). European Society of Radiology; 2015. http://posterng.netkey.at/esr/viewing/ index.php?module=viewing_poster&task=&pi=130194& searchkey= [accessed 17 February 2016]. 23 Pitt T, Brethauer S, Sherman V, Udomsawaengsup S, Metz M, Chikunguwo S et al. Diagnostic laparoscopy for chronic abdominal pain after gastric bypass. Surg Obes Relat Dis 2008; 4: 394 398.