Reduction En-masse of Inguinal Hernia with Incarcerated Bowel: Report of a Rare Case

Background

Reduction en-masse of an inguinal hernia is defined as migration or reduction of the inguinal hernia sac into the preperitoneal space, while its bowel component is stuck in the hernia sac. It is a rare condition that occurs approximately 1 out of 13 000 hernias [1]. The current incidence rate is estimated to be even lower since there has been an increase in the number of patients with previously repaired inguinal hernias [2]. Reduction en-masse is most commonly caused by forcible attempts during manual reduction. However, this condition also occurs naturally, mostly in the setting of chronic and repetitive inguinal hernia and reduction. Although it can be diagnosed by specific computed tomographic (CT) findings [3], many radiologists are not familiar with the disease because of its rarity and the lack of published radiological reports, thus making it difficult to diagnose. Herein, we report a rare case of reduction en-masse of an inguinal hernia with CT findings. We also conducted a review of the literature related to this disease.

Case Report

A 76-year-old male patient presented in the Emergency Department complaining of abdominal pain for 2 h before admission. He had a 4-year history of repeated left inguinal hernia and manual reduction, but he had no underlying disease or surgical history. Surgical repair of a left inguinal hernia was scheduled in the next few days. At the initial physical examination there was increased bowel sound and tenderness in the whole abdomen. Laboratory studies showed a white blood cell count (WBC) of 10 000 cells/mm3 (normal range, 4000 to 10 000 cells/mm3). An abdominal radiograph showed a distended small bowel loop in the left lower quadrant. Contrast-enhanced CT images revealed a small-bowel obstruction, showing dilatation from the distal jejunum to the proximal ileum and a closed-loop obstruction showing a 6.2-cm oval-shaped sac containing a short segment of ileal loop and fluid collection in the left lower quadrant. The sac was located in the preperitoneal space and superior to the left inguinal region. The preperitoneal space is situated posteriorly to the anterior abdominal wall and anteriorly to the parietal peritoneum. There was fat infiltration and edema in the ipsilateral inguinal region. The urinary bladder was compressed by the hernia sac due to a mass effect. The narrowed neck of the hernia sac was visible and there was closed-loop obstruction with 2 points of obstruction (Figure 1A–1G). The patient underwent surgical reduction with herniorrhaphy using the transabdominal preperitoneal (TAPP) technique, and an incarcerated small bowel loop was discovered in the hernia sac, along with fluid. During the operation, the surgeon confirmed the incarcerated bowel had viability. After the surgery, the patient recovered from abdominal pain, and he was sent home on the third day after the operation.

Discussion

Luke, in 1843, was the first to report on reduction en-masse [4]. It occurs in patients with a history of repetitive inguinal herniation and reduction causing fibrotic change of the hernia orifice to develop a narrow neck, which makes it hard for the bowel to withdraw from the sac [5]. If the inguinal hernia is forcibly reduced, the hernia sac with a trapped bowel loop can migrate into the preperitoneal space and a closed-bowel loop obstruction with incarceration remains. Early diagnosis and surgical reduction are important because the delay in prompt management can be associated with bad prognosis [6,7]. Physicians can miss this condition upon physical examination, as the hernia appears to be grossly smaller; therefore, diagnosis based on specific CT findings is crucial for appropriate management. CT images of reduction en-masse of an inguinal hernia show a specific feature, the “Preperitoneal hernia sac sign”, in which the hernia sac is located in the preperitoneal space of the lower quadrant near the inguinal fossa, comprising an incarcerated bowel [3,8]. This location is a specific finding used to diagnose reduction en-masse (Figure 2). Also, prominent soft tissue in the ipsilateral inguinal area can be another clue for diagnosis and suggests a residual hernia sac and/or inflammation caused by recurrent hernia. The combination of these radiologic findings enables the detection of reduction en-masse of an inguinal hernia.

Conclusions

Here, we report a case of reduction en-masse of an inguinal hernia in a patient with a history of repeated left inguinal herniation and reductions. Although clinical symptoms can be non-specific, it is possible to diagnose with careful history taking and characteristic radiologic findings. Therefore, we suggest that clinical and radiological awareness are very important for accurate diagnosis and management in patients with reduction en-masse of an inguinal hernia.