Original Article
CT findings in Petersen’s hernia as a complication of bariatric surgery with a Roux-en-Y gastric bypass Achados tomográficos na hérnia de Petersen como complicação de cirurgia bariátrica com bypass gástrico em Y de Roux Mauricio Álvares Salum Ximenes1, Ronaldo Hueb Baroni2, Ronald Trindade3, Rodrigo Abdala4, Marcelo de Castro Jorge Racy5, Renato Alonso Moron6, Alberto Goldenberg7, Thomas Szego8, Almino Cardoso Ramos9, Marcelo Buarque de Gusmão Funari10
ABSTRACT
RESUMO
Objectives: To describe tomographic findings in Petersen’s hernia associated with laparoscopic Roux-en-Y gastric bypass surgery. Methods: Two radiologists, experts in abdominal radiology, independently and retrospectively reviewed four cases of Petersen’s hernia confirmed surgically in three patients, between March 2007 and July 2008, who had undergone laparoscopic Roux-en-Y gastric bypass surgery with an antecolic anastomosis for treating morbid obesity. The main imaging findings were the presence and location of abdominal distention, the herniated intestinal loop segment, the presence of mesenteric vessel rotation and haziness of mesenteric fat, the position of the Treitz angle ligament and the course of the ileum. Results: In all cases, abdominal distention was located in the upper abdomen; the herniated jejunal loop was located above the gastric level; mesenteric vessel rotation was associated with mesenteric fat haziness; the middle/distal ileum descended from the left hypochondrium; and the Treiz angle was displaced anteriorly and to the right. Both examiners fully agreed with the analysis of findings. Conclusions: The association of computed tomography findings described in patients with a history of bariatric surgery is a strong predictor of Petersen’s hernia.
Objetivo: Descrever os achados tomográficos associados à hérnia de Petersen em pacientes submetidos à gastroplastia redutora com Y de Roux. Métodos: Foram analisados retrospectivamente, por dois observadores independentes, quatro casos com diagnóstico cirúrgico confirmado de hérnia de Petersen, ocorridos em três pacientes no período de Março de 2007 a Julho de 2008, todos submetidos a bypass gástrico através de Y de Roux por via videolaparoscópica com anastomose antecólica para tratamento de obesidade mórbida. Os principais aspectos analisados nas imagens foram a presença e a localização da distensão abdominal; o segmento de alça intestinal herniado; a presença de rotação dos vasos mesentéricos e densificação da gordura do mesentério; a posição do ângulo de Treitz, e o trajeto do íleo. Resultados: Em todos os casos analisados, foram caracterizados os seguintes achados: distensão abdominal no andar superior do abdome; localização do segmento herniado de alça jejunal acima do nível gástrico; rotação dos vasos mesentéricos acompanhada de densificação da gordura mesenterial; trajeto descendente do íleo médio/distal a partir do hipocôndrio esquerdo; e o deslocamento anterior e para a direita do ângulo de Treitz. Houve concordância total entre os dois examinadores na análise destes achados. Conclusões: Os achados tomográficos descritos, quando encontrados nos exames de tomografia computadorizada em pacientes submetidos à gastroplastia redutora, são fortes preditores de hérnia de Petersen.
Keywords: Hernia; Tomography, X-ray computed; Gastroplasty/ methods; Postoperative complications
Study carried out at the Imaging Department of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil. Resident of Radiology at Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
1
Radiologist of the Medical Staff of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil
2
Radiologist, Post-graduate student at Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
3
Radiologist, Post-graduate student at Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
4
Radiologist of the Medical Staff of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
5
Radiologist of the Medical Staff of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
6
Surgeon of the Medical Staff of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
7
Surgeon of the Medical Staff of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
8
Surgeon of the Medical Staff of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
9
10
Radiologist, Coordinator of the Imaging Department of Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
Corresponding author: Mauricio Alvares Salum Ximenes – Rua José Galante, 30 – apto. 124 – Vila Suzana – CEP 05642-000 – São Paulo (SP), Brasil – Tel.: 11 7878-0009 – e-mail:
[email protected] Received on: Feb 31, 2008 – Accepted on: Oct 26, 2008
einstein. 2008; 6(4):452-8
CT findings in Petersen’s hernia as a complication of bariatric surgery with a Roux-en-Y gastric bypass
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Descritores: Hérnia; Tomografia computadorizada por raios-x; Gastroplastia/métodos; Complicações pós-operatórias
INTRODUCTION Obesity is a chronic disease characterized by excessive accumulation of adipose tissue in the body. It has become the most prevalent public health issue worldwide; according to statistics of the Centers for Disease Control and Prevention (CDC), 64% of North Americans are above the overweight range(1). Given the multifactorial etiology of obesity, its treatment requires a variety of approaches. Conventional medical therapy for morbid obesity continues yielding unsatisfactory results; 95% of patients return to their initial weight within two years. Referrals for bariatric surgery have currently increased due to the need for more effective interventions in the management of severely obese patients(2-4). Candidates for surgery are patients with a Body Mass Index (BMI) above 40 kg/m² or a BMI over 35 kg/m² associated with comorbidities, such as sleep apnea, type 2 diabetes mellitus, arterial hypertension, dyslipidemia and difficulty ambulation, among other conditions that are difficult to manage medically(5-8). The Roux-en-Y gastric bypass is currently one of the preferred procedures. The minimum amount of the gastrointestinal tract that is excluded from intestinal transit is the distal stomach, the duodenum, and about 40 cm of the proximal jejunum. The standard Roux loop measures about 75 cm. The gastric bypass may be done by open surgery or laparoscopy, the latter being currently preferred(9-10). The upper pouch is made horizontally or vertically, and has a capacity of about 15 to 25 ml; the distal stomach is separated or fully excluded. An anastomosis (proximal anastomosis) is done between this small pouch and part of the jejunum (feeding loop) that was sectioned close to its origin(10). The afferent or biliopancreatic loop starts from the remaining stomach, passing along the duodenum until the proximal jejunum, in which the jejuno-jejunal anastomosis (distal anastomosis) is performed. The anastomotic loop may be retrocolic or antecolic. The retrocolic anatomosis creates space in the mesentery, opening the possibility of a transmesenteric hernia. Petersen’s hernia may occur in both types of anastomosis(9-10) (Figure 1). Internal hernias are the main causes of late postoperative intestinal obstruction; its incidence reaches up to 9.7%(9). Petersen’s hernia is a less common finding in most published papers compared to transmesocolic hernia(10-11). Imaging exams have an important role in the early diagnosis and surgery of this
G P Retrocolic loop
Antecolic loop
Mesocolon
AL
Figure 1. The blue arrow shows the Petersen's space (GP = gastric pouch; AL = afferent loop)
condition, with multislice computed tomography being the most accurate method in such cases.
OBJECTIVE The purpose of this study was to describe the tomographic findings of internal hernias along Petersen’s space (Petersen’s hernia) following Rouxen-Y gastric bypass surgery. MethodS A review was made of all abdominal computed tomography exams done in the Image Department of Hospital Israelita Albert Einstein, stored in the Picture Archiving and Communications System (PACS), to select those patients with a tomographic diagnosis of internal hernias. Three patients with a confirmed surgical diagnosis of Petersen’s hernia, between March 2007 and July 2008, were selected. All three had undergone laparoscopic Roux-en-Y gastric bypass surgery with an antecolic anatomosis for the treatment of morbid obesity. The hernia recurred in one of these patients, resulting in four cases. Two radiologists – experts in abdominal radiology – independently
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Ximenes MAS, Baroni RH, Trindade R, Abdala R, Racy MCJ, Moron RA, Goldenberg A, Szego T, Ramos AC, Funari MBG
reviewed the images to identify the main tomographic findings suggesting internal hernias. The main image findings were the presence and site of abdominal distention, the herniated intestinal loop segment, the presence of mesenteric vessel rotation, and mesenteric fat haziness, the position of the Treitz angle, and the course of the ileum. Demographic (sex, age) or clinical data related to the procedure (type of surgery, type of surgical approach, intraoperative events, additional procedures, postoperative complications) and the clinical picture at the time of diagnosis were taken and correlated with the image findings. All tomography exams were performed at the same unit, according to a standardized protocol, using helical/multislice computed tomography devices. In one case a 16-row detector tomography device (Toshiba Aquilion™ 16) with 2 mm sections was used. In the other cases, a 64-row detector tomography device (Toshiba Aquilion™ 64) with 0.5 mm sections was used. Oral and intravenous non-ionic iodinated contrast was used in all exams. Petersen’s hernia was confirmed by laparoscopic surgery in all cases, followed by reduction of the herniated segment and closure of Petersen’s space (Figure 2).
Chart 1. Clinical findings of patients Patients and hernia recurrence
Sex
Patient 1
Female
32
Patient 2
Female
41
Patient 3
Male
39
Recurrence
Male
40
Age
Time between surgery and Clinical picture occurrence of hernia One year and two Abdominal pain months and vomiting One year Abdominal pain One year and one Abdominal pain month One year after the first Abdominal pain episode
with an antecolic anastomosis. There were no significant intraoperative and immediate postoperative events. The first tomographic imaging parameter to be evaluated was the pattern of intestinal loop distension. In all patients there was mild distension of small intestine loops in the upper abdomen; in two cases these loops were located preferentially in the left hypochondrium (Figure 3). A key finding for tomographically defining and diagnosing the herniated segment was a jejunal loop located above the stomach, which was seen in all cases (Figure 4); this finding was accompanied by mesenteric vessel
A
Figure 2. Videolaparoscopic image for Petersen’s hernia reduction. The green arrows indicate the Petersen's space and the blue arrows, the herniated loop
Results Chart 1 shows that one patient was male and two patients were female; age ranged from 32 to 40 years. In all cases the hernia occurred about one year after bariatric surgery. In the case that recurred, the second hernia occurred about one year after the procedure for treating the first hernia. The predominant symptom was abdominal pain. Only one patient presented nausea and vomiting together with pain. All patients underwent videolaparoscopic Roux-en-Y gastric bypass surgery einstein. 2008; 6(4):452-8
B
C
Figure 3. Abdominal computed tomography with oral and intravenous contrast medium in the portal phase. (A) Axial image; (B) coronal reconstruction; (C) sagittal reconstruction. Gastrojejunal anastomosis (green arrow); distended herniated loop (red arrows); excluded stomach (yellow arrows)
CT findings in Petersen’s hernia as a complication of bariatric surgery with a Roux-en-Y gastric bypass
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Figure 4. Abdominal computed tomography with oral and intravenous contrast medium; coronal reconstruction in the portal phase. The yellow arrow shows the jejuno-jejunal anastomosis; the red arrow, the herniated loop
stretching and engorgement, which produced a “mushroom-like” aspect (Figure 5). Mesenteric vessel rotation, described as the whirl sign or mesenteric swirl, and mesenteric fat haziness (Figure 6) were seen in all cases; in one patient there was also adjacent enlargement of peritoneal lymph nodes. A further finding was the position of the Treitz angle that, in all cases, was displaced anteriorly and to the right (Figure 7). Ileal loop positioning
Figure 5. Abdominal computed tomography with oral and intravenous contrast medium; coronal reconstructions in the portal phase. The blue arrows indicate the rotation of the mesenterium and vessels; yellow arrows show herniated intestinal segment (“mushroom-like” aspect)
Figure 6. Abdominal computed tomography with oral and intravenous contrast medium; axial images in the portal phase. Observe rotation of mesenteric vessels (“whirl sign”), accompanied by mesenteric fat haziness
showed that middle and distal ileal segments had a descending trajectory in the left hypochondrium in all cases (Figure 8). The main tomographic findings in Petersen’s hernia are shown in Chart 2.
Figure 7. Abdominal computed tomography with oral and intravenous contrast medium; axial images in the portal phase. Note the ligament of Treitz was displaced anteriorly and to the right
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Ximenes MAS, Baroni RH, Trindade R, Abdala R, Racy MCJ, Moron RA, Goldenberg A, Szego T, Ramos AC, Funari MBG
Figure 8. Abdominal computed tomography with oral and intravenous contrast medium. Axial images in the arterial phase showing the ileal course Chart 2. Tomographic findings in Petersen’s hernia Clinical findings Abdominal distension in the upper abdomen Herniated intestinal loop segment above the gastric level Rotation of mesenteric vessels (whirl sign) Mesenteric fat haziness Ligament of Treitz displaced anteriorly and to the right Middle/distal ileum courses downwards in the left hypochondrium
Discussion Knowledge of surgical technique and ensuing anatomical changes in the abdominal cavity, as well as possible complications is essential for investigating and diagnosing the cause of abdominal pain in patients who have undergone bariatric surgery. Postoperative image assessments may be carried out using conventional radiology or computed tomography. Contrasted radiography makes it possible to dynamically evaluate the remaining gastric reservoir and the gastrojejunal anastomosis, verifying retention and emptying by means of oral contrast media. Multislice computed tomography adds an assessment einstein. 2008; 6(4):452-8
of extraluminal structures; its spatial resolution is ideal for examining the surgical bed and the anatomical alterations due to surgical manipulation. The main postoperative complications include the dumping syndrome, stenosis of the anastomosis, marginal ulcers, dehiscence, leaks and – more commonly – intestinal obstruction(11-12). Obstruction is usually caused by marked intestinal loop edema in the immediate postoperative period; this usually resolves spontaneously. An iatrogenic etiology – excessive suturing – is a second cause of early obstruction. Late postoperative obstruction may be due to adhesions, fibrotic stenosis, intussusception or – more often – internal hernias(13). These may also cause volvulus and Roux loop ischemia. An early diagnosis of obstruction is essential to avoid further complications(14). The incidence of internal hernias following videolaparoscopic gastric bypass surgery ranges from 1.8 to 9.7% much higher than that seen when this procedure is performed by open surgery(9). Another contributing factor for internal hernias may be the creation of a potential space after marked weight loss(14-15). Blachar et al.(11) suggested that the transmesocolic hernia is the most common internal hernia after Roux-en-Y gastric bypass surgery; their postoperative follow-up of 463 patients revealed that 23 developed intestinal obstruction, of which 14 were due to internal hernias, 13 were transmesocolic and one was Petersen’s hernia. Higa, Ho and Boone monitored 2,000 operated patients and found 66 cases of internal hernias, of which only five where in Petersen’s space(10). Lockhart et al. reviewed the complications of 501 patients who underwent Roux-en-Y gastric bypass surgery and found 19 cases of internal hernias, of which 13 were Petersen’s hernias(16). Petersen’s hernia is a specific type of internal hernia in which the intestine moves into a potential space between the caudal surface of the transverse mesocolon and the tip of the Roux loop (Petersen’s space). Although Petersen’s hernia occurs in a potential space behind the gastrojejunoanastomosis, its clinical presentation and image findings are similar to those of other internal hernias. This follow-up showed that all cases occurred about one year after bariatric surgery. Higa, Ho and Boone(10), however, showed that there is marked variability between surgery and the occurrence of internal hernias. Rapid weight loss appears to be a contributing factor for opening potential spaces through which hernias may form. Abdominal pain has been described as the main symptom of an internal hernia, as was the case in the present series; this sign may present as pain observed in postprandial mesenteric ischemia, and may or not be associated
CT findings in Petersen’s hernia as a complication of bariatric surgery with a Roux-en-Y gastric bypass
with signs of upper intestinal obstruction (nausea and vomiting). There are certain image findings – published in the literature – in patients who have undergone Roux-en-Y gastric bypass bariatric surgery that strongly suggest an internal hernia; it was seen other findings in this clinical context that suggested the diagnosis of a hernia in Petersen’s space. Mesenteric vessel rotation, described as the whirl sign, together with mesenteric fat haziness, has been shown in various articles to be the most sensitive sign for the diagnosis of internal hernias(15-16). These findings were evident in all patients; mesenteric lymph nodes were also more numerous, and enlarged in one case. Distended intestinal loops in the left hypochondrium presenting a mushroom shape and mesenteric vessel elongation(15-16) are a consequence of vascular engorgement and mesenteric fat haziness; in a coronal reconstruction, with herniated loops in the upper pole, these findings have a mushroomlike appearance. Lockhart et al.(16) also described this finding, which increases the diagnostic specificity; it can be seen in two of our cases. It was also noted that the small bowel loop that is herniated in Petersen’s hernia is a jejunal loop segment which becomes located above the gastric level. Signs of intestinal obstruction have often been described in the radiological literature, including signs of internal hernias(12,14-17). An abdominal distension is located preferentially in the upper abdomen, tending towards the left hypochondrium. It was observed that the middle/distal ileum courses downwards in the left hypochondrium, and has a habitual horizontal path up to the cecum. Displacement of the Tritz angle, crossing anteriorly towards the right, was clearly demonstrated in these patients. Although our tomographic findings agreed with most published cases, this study was limited by the small sample. The power of this study is also lower, since there was no comparison group consisting of patients with other types of postoperative hernias occurring in bariatric surgery. Some signs, such as distended intestinal loops, the whirl sign and the mushroom-like appearance are common to other types of internal hernias. A precise diagnosis of Petersen’s hernia requires specifically finding and locating the herniated intestinal segment. However, the present study has a didactic purpose to clearly illustrate the computed tomographic findings in this type of hernia, with surgical proof.
CONCLUSIONS With the growing number of indications of surgery for treating morbid obesity, imaging assessments
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have become indispensable tools in the diagnosis of complications. Internal hernias, including Petersen’s hernia, generally manifest in the late postoperative period and may have a non-specific presentation. The set of imaging findings in computed tomography of patients with Petersen’s hernia, amply discussed in this study, is a spectrum of highly suggestive changes for diagnosis of this condition.
Acknowledgments To the radiologist Dr. Diogo Lago Pinheiro for his relevant contribution to the present study. REFERENCES 1. Centers for Disease Control and Prevention. Overweight and obesity: obesity trends: 1991–2001 prevalence of obesity among U.S. adults by state – behavioral risk factor surveillance system (BRFSS) 2001 self reported data [Internet]. [cited 2006 Mar 20]. Available at: www.cdc.gov/nccdphp/dnpa/ obesity/trend/prev_reg.htm. 2. Pi-Sunyer FX. Medical complications of obesity. In: Brownell KD, Fairburn CG. Eating disorders and obesity. New York: Guilford Press; 1995. p. 401-6. 3. World Health Organization [WHO]. Obesity: preventing and managing the global epidemic – report of a WHO consultation on obesity. Geneva: WHO; 1997. 4. Karlsson J, Sjöström L, Sullivan M. Swedish obese subjects (SOS) – an intervention study of obesity. Two-year follow up of health-related quality of life (HRQL) and eating behavior after gastric surgery for severe obesity. Int J Obes Relat Metab Disord. 1998;22(2):113-26. 5. Coutinho W. Consenso Latino-Americano de obesidade. Arq Bras Endocrinol Metab. 1999;43(1):21-67. 6. National Institute of Health (NIH). Consensus Statements: Gastrointestinal Surgery For Severe Obesity. Bethesda: NIH; 1991. 7. American Society of Bariatric Surgery [ASBS]. Rationale for the surgical treatment of morbid obesity; 1998. 8. International Federation for the Surgery of Obesity [IFSO]. Website patient selection for bariatric surgery; 2001. 9. Capella RF, Iannace VA, Capella JF. Bowel obstruction after open and laparoscopic gastric bypass surgery for morbid obesity. J Am Coll Surg. 2006;203(3):328-35. 10. Higa KD, Ho T, Boone KB. Internal hernias after laparoscopic Roux-en-Y gastric bypass: incidence, treatment and prevention. Obesity Surgery. 2003;13(3):350-4. 11. Blachar A, Federle MP, Pealer KM, Ikramuddin S, Schauer PR. Gastrointestinal complications of laparoscopic Roux-en-Y gastric bypass surgery: clinical and imaging findings. Radiology. 2002;223(3):625-32. 12. Labrunie EM, Marchiori E. Obstrução intestinal pós-gastroplastia redutora pela técnica de higa para tratamento da obesidade mórbida: aspectos por imagem. Radiol Brasil. 2007;40(3):161-5. 13. Chandler RC, Srinivas G, Chintapalli KN, Schwesinger WH, Prasad SR. Imaging in bariatric surgery: a guide to postsurgical anatomy and common complications. AJR Am J Roentgenol. 2008;190(1):122-35. 14. Reddy SA, Yang C, McGinnis LA, Seggerman RE, Garza E, Ford KL 3rd. Diagnosis of transmesocolic internal hernia as a complication of retrocolic gastric bypass: CT imaging criteria. AJR Am J Roentgenol. 2007;189(1):52-5. 15. Takeyama N, Gokan T, Ohgiya Y, Satoh S, Hashizume T, Hataya K, et al. CT of internal hernias. Radiographics. 2005;25(4):997-1015.
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16. Lockhart ME, Tessler FN, Canon CL, Smith JK, Larrison MC, Fineberg NS, et al. Seven signs after gastric bypass. AJR. 2007;188(3):745-50.
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17. Blachar A, Federle MP, Dodson SF. Internal hernia: clinical and imaging findings in 17 patients with emphasis on CT criteria. Radiology. 2001;218(1):68-74.
