Hernia DOI 10.1007/s10029-014-1217-9
Reduction en masse of inguinal hernia: MDCT findings of two cases S. Hoshiai • K. Mori • M. Shiigai • Y. Uchikawa A. Watanebe • S. Shiotani • S. Atake • M. Minami
Received: 31 July 2013 / Accepted: 5 January 2014 Ó Springer-Verlag France 2014
Abstract Reduction en masse of inguinal hernia is an extremely rare complication arising from manual reduction of a hernia. The hernial content remaining in the hernia sac returns above the inguinal canal but remains in the abdominal wall. Accurate preoperative diagnosis of reduction en masse of inguinal hernia is challenging because the hernia appears to be reduced upon physical examination. We experienced two cases of reduction en masse. In both cases, multidetector row computed tomography revealed a closed loop obstruction near the inguinal fossa. In addition, we observed a continuous tract of the hernia sac to the inguinal canal and prominent peritoneal thickening suggestive of the hernia sac. Keywords Hernia Inguinal hernia Reduction en masse Atypical hernia MDCT
Introduction Reduction en masse of inguinal hernia is an extremely rare complication resulting from manual reduction of a hernia. S. Hoshiai (&) K. Mori M. Shiigai Y. Uchikawa A. Watanebe M. Minami Department of Diagnostic and Interventional Radiology, University of Tsukuba Hospital, 2-1-1 Amakubo, Tsukuba, Ibaraki, Japan e-mail: [email protected]
S. Shiotani Department of Radiology, Tsukuba Medical Center Hospital, 1-3-1 Amakubo, Tsukuba, Ibaraki, Japan S. Atake Department of Emergency Medicine, Tsukuba Medical Center Hospital, 1-3-1 Amakubo, Tsukuba, Ibaraki, Japan
It is a condition in which the hernial content remaining in the hernia sac returns above the inguinal canal but remains present in the abdominal wall. The inguinal hernia appears to be reduced upon physical examination, and this makes preoperative diagnosis difficult . Therefore, accurate preoperative diagnosis requires imaging evaluations including multidetector row computed tomography (MDCT). We report two cases of reduction en masse of inguinal hernia and their MDCT findings. Case 1 A 76-year-old man with no history of abdominal surgery was admitted to our hospital after a 3-day bout of vomiting and abdominal pain. Upon physical examination he was found to have a little tenderness in the lower abdomen. No masses were found even with deep palpation. His vital signs were unremarkable. An abdominal radiograph revealed small bowel dilatation, and computed tomography (CT) was urgently performed (Figs. 1, 2). Non-contrast abdominal and pelvic CT showed diffuse dilation of the small bowel and a closed loop near the urinary bladder. An incarcerated intestine near the bladder distorted the bladder wall into a beak-like deformity. An emergency operation was performed with a presumed diagnosis of a strangulated small bowel obstruction due to a supravesical hernia. Laparotomy via the transabdominal approach revealed a short segment of the incarcerated small bowel wrapped with thickened peritoneum in the shape of a purse. The incarcerated bowel was pulled out. The bowel showed congestion and edema but no necrosis and hence, was not resected. The peritoneal purse wrapping the small bowel had formed a fibrous collar and constricted the herniated bowel. A deep portion of the hernia sac continued into the right inguinal canal. The hernia sac was
Fig. 1 Case 1. Non-contrast axial CT scans at the inguinal levels show thickened peritoneum (white arrows) wrapping around the bowel loop with surrounding peripheral fat stranding. This peritoneum continued into the right inguinal canal (arrowheads)
Fig. 2 Case 1. a Reformatted coronal CT image shows a short segment of the small bowel wrapped with thickened peritoneum in a purse-like shape. The gate of the purse (white arrow) constricted the herniated bowel with dilatation of the oral side (small arrowheads).
b Reformatted oblique sagittal CT along the right inguinal canal shows the hernia sac continuing to the right inguinal canal (white arrows). The urinary bladder shows a beak-like deformity (large arrowhead in a and b)
Fig. 3 Case 2. Contrast-enhanced axial CT images show a closed loop near the right inguinal fossa. Note the remarkably thickened peritoneum around the incarcerated bowel (large white arrows). A
tract of the hernia sac containing fluid was continuous to the inguinal canal (arrowhead). The right inferior epigastric vessels are located medial to the hernia sac (small white arrows)
opened and resected. The transinguinal approach revealed a hernia near the external inguinal ring. The hernia continued to the previously indicated sac under the preperitoneal cavity. These operative findings proved reduction en masse of right inguinal hernia. The patient’s postoperative course was uneventful. Through a postoperative interview, he was found to have experienced a repeat right inguinal hernia and to have sometimes manually reduced his groin bulge himself.
bladder was not observed as it had collapsed owing to the insertion of a urinary catheter. The right epigastric vessels were shifted medially by the hernia tract. These findings were consistent with reduction en masse of a right inguinal hernia. A laparotomy was performed via the transabdominal approach and revealed a short segment of incarcerated small bowel wrapped with thickened peritoneum in a purse-like shape. The incarcerated bowel was pulled out and showed congestion and necrosis. The 10-cm long bowel was thus resected and subsequently a right inguinal hernioplasty was performed. The patient recovered uneventfully and was discharged.
Case 2 A 65-year-old man was admitted to our emergency department complaining of abdominal pain and vomiting for 5 days. He had occasionally reduced a right inguinal hernia manually by himself over the past 5 years. Contrastenhanced CT showed a closed loop obstruction near the right inguinal fossa. The hernia sac was observed to be continuous with the inguinal canal, which was filled with fluid. A remarkably thickened peritoneum was also observed around the closed loop (Fig. 3). Distortion of the
Discussion Reduction en masse of inguinal hernia is a clinical state in which a hernia sac reduces into the preperitoneal space together with its contents, but the retained bowel remains incarcerated (Fig. 4) [1–9]. It tends to occur in an
Hernia Fig. 4 Schematic drawing of reduction en masse (reprinted with permission from reference ). a An incarcerated inguinal hernia with a tight unyielding neck. b Inversion of the hernia sac with entrapment of the herniated bowel. Asterisk indicates thickened peritoneum of hernia sac
individual who repeatedly attempts to reduce an inguinal hernia himself. The condition is quite rare. It was reported to occur in approximately 1 of 13,000 hernias in an early literature review . The current incidence is probably far less than this earlier estimation . There are two types of reduction en masse of inguinal hernia: indirect and direct. Hattori et al.  reviewed 14 cases of reduction en masse of inguinal hernia. All occurred in males who were in their fifth decade of life or older. Unlike the usual inguinal hernias seen in elderly men, eight of them had indirect hernias, while two of them had direct ones (4 cases were of unknown type). This disease requires transabdominal surgical treatment as it cannot be satisfactorily treated with an inguinal approach. Although taking a careful medical history can suggest this condition, it is difficult to diagnose preoperatively because the hernia seems to be reduced upon physical examination. In this context, imaging diagnosis plays an important role. However, only a few cases with imaging findings have been reported. Kitami et al.  reported the CT findings of reduction en masse of 2 cases: (a) closed loop obstruction with a ball-like bowel loop, (b) location adjacent to the inguinal fossa, (c) a circular funicular structure at the obstruction point, (d) a beak of the bladder along the closed loop, and (e) prominent unilateral inguinal soft tissue. These findings were also observed in our cases. In addition, prominent thickened peritoneum was observed
around the closed loop. This finding may be based on fibrotic changes to the peritoneum induced by chronically repeated reduction, although double-layered peritoneum of the hernial sac and/or minimal fluid accumulation in the sac can contribute to the finding. To the best of our knowledge, there has been no previous description of locally thickened peritoneum associated with this condition, but the same finding can be observed on the previously reported five images [4–6, 8]. On the other hand, a supravesical hernia, which was our preoperative diagnosis for case 1, develops at the supravesical fossa between the remnants of the urachus and the unilateral obliterated umbilical artery. In the literature, a supravesical hernia is reported to result in an incarcerated intestine that is so close to the bladder that it actually distorts the bladder wall. Moreover, an external supravesical hernia also exhibits unilateral inguinal soft tissue [10, 11]. These findings are common in reduction en masse of inguinal hernia and so a supravesical hernia must be considered among the differential diagnoses of reduction en masse of inguinal hernia. Retrospectively, in case 1, preoperative MDCT revealed that the right inferior epigastric vessels had been shifted to the medial side by the continuous tract of the hernia sac to the inguinal canal (Fig. 5). In supravesical hernia, this sac always shifts the inferior epigastric vessels laterally. Therefore, this finding permits a definitive diagnosis of reduction en masse of indirect inguinal hernia. In case 2,
around the closed loop; and (2) in reduction en masse of an indirect inguinal hernia, which is far more common than that of a direct inguinal hernia, noting the relationship between the inferior epigastric vessels and the tract from the hernia sac is important for definitively differentiating this disorder from a supravesical hernia. Conflict of interest interest.
All authors declare to have no conflicts of
Fig. 5 Case 1. Reformatted coronal maximal intensity projection image demonstrates the medial shifting of the right inferior epigastric vessels (arrowheads) by the tract of the hernia sac (arrow) continuous to the inguinal canal
we were able to correctly diagnose reduction en masse of inguinal hernia based on the findings above. In the case of reduction en masse of direct inguinal hernia, it may be difficult to distinguish this condition from a supravesical hernia. To distinguish these, we need to identify the gate of the hernia sac: the gate of the reduction en masse of a direct inguinal hernia is lateral to the medial umbilical ligament, whereas that of a supravesical hernia is medial to the medial umbilical ligament.
Conclusion Preoperative diagnosis of reduction en masse of inguinal hernia is challenging because the hernia seems to be reduced upon physical examination. Therefore, imaging evaluation is important for patient management. We present important new imaging findings for diagnosing this disease: (1) a prominent thickened peritoneum observed
1. Ponka JL (1980) Hernias of the abdominal wall. Saunders, Philadelphia, pp 496–500 2. Parvey LS, Himmelfarb E, Rabinowitz J (1974) Spontaneous reduction of hernia ‘‘en masse’’. Am J Roentgenol 121(2):252–255 3. Bay-Nielsen M (2013) Complications in hernia of general. In: Kingsnorth AN, LeBlanc KA (eds) Management of Abdominal Hernias, 4th edn. Springer, London, pp 171–184 4. Kitami M, Yamada T, Ishii T et al (2008) CT findings of ‘‘reduction en masse’’ of an inguinal hernia. Eur J Radiol Extra 67(3):e111–e114 5. Wu CC, Kang JC, Huang YM (2012) Laparoscopic transabdominal preperitoneal hernioplasty for reduction en masse of an incarcerated inguinal hernia: a case report. J Gastrointest Surg 16(7):1433–1435 6. Ravikumar H, Babu S, Govindrajan MJ et al (2009) Reduction en-masse of inguinal hernia with strangulated obstruction. Biomed Imaging Interv J 5(4):e14 7. Bernie AM, Schwanke T, Keutgen X et al (2012) Reduction en masse in a 7-year-old boy: an interesting case. J Pediatr Surg 47(5):E19–E20 8. Hattori T, Fujimura T, Hashimoto T et al (2010) A case of ‘‘reduction-en-masse’’ of an inguinal hernia. J Jpn Surg Assoc 71(9):2473–2476 (in Japanese with English abstract) 9. Pearse HE (1931) Strangulated hernia reduced ‘‘en masse’’. Surg Gynec Obstet 53:822–828 10. Sasaya T, Yamaguchi A, Isogai M et al (2001) Supravesical hernia: CT diagnosis. Abdom Imaging 26(1):89–91 11. Cisse M, Konate I, Ka O et al (2009) Internal supravesical hernia as a rare cause of intestinal obstruction: a case report. J Med Case Rep 3:9333