Introduction: Internal hernia (IH), the protrusion of a viscus through a peritoneal or mesenteric aperture, is a rare cause of small bowel obstruction. Except for ones complicating bariatric surgery, IHs are sparsely described in the literature. We report one of the largest series of IHs, excluding ones formed as a consequence of operations for morbid obesity. This study discusses the clinical presentation, surgical management, and outcomes of IHs at our institution. Methods: Retrospective review of patients at our institution yielded 49 cases of surgically confirmed IH between 1994 and 2004. Results: Majority of patients presented with abdominal pain (85.7%), nausea (77.6%) and vomiting (71.4%) for median 3 days (Range: hours to 5 months). Small bowel obstruction was a common radiographic finding in 31% of obstructive series, 44% of CT scans, and 75% of small bowel series. While 16% of CT scans and 25% of small bowel series were suspicious for IH, in no cases the preoperative diagnosis of IH was made. The average number of days from admission to surgery was 1.7 days. All IHs consisted of small bowel except for one patient with herniation of terminal ileum and proximal ascending colon. The most frequent IH were transmesenteric (58.0%) and 34 hernias (69%) were caused by defects secondary to previous surgery (see table). All IHs were reduced and the mesenteric and peritoneal defects were repaired. Twenty-two patients had compromised bowel at exploration and 11 (22.5%) had irreversible changes requiring small bowel resection. Two patients required re-exploration for postoperative abscesses. The mean postoperative hospital length of stay was 10.9 days (Range: 3 - 65 days). The overall mortality rate from our series is 2%, and the morbidity rate is 8.2%. Conclusion: We have found that transmesenteric hernias, as complications of previous surgeries, are the most prevalent IH. Preoperative diagnosis of IH is extremely difficult because of the nonspecific clinical presentation. However, if discovered promptly, IHs can be repaired with acceptable morbidity and mortality.
Internal Hernia Type | n (%) |
Transmesenteric | 28 (58) |
Paraduodenal | 6 (12) |
Transomental | 5 (10) |
Intersigmoid | 3 (6) |
Pericecal | 3 (6) |
Paravesical | 3 (6) |
Foramen of Winslow | 1 (2) |