Rare strangulated intenal hernia following extraperitoneal colostomy for rectal cancer operation: A case report

Introduction: Few cases of intestinal obstruction after colostomy are caused by internal hernia. Some institutions perform stomas through the extraperitoneal route because some patients experience an internal hernia outside the stoma performed through the intraperitoneal route. Presentation of case: A 72-year-old woman presented with a history of laparoscopic abdominoperineal resection (APR). A sigmoid colostomy was performed via the extraperitoneal route during APR. One month after APR, the patient presented to the emergency department of our hospital with abdominal pain and vomiting. Computed tomography revealed that the small intestine had passed through the extraperitoneal tunnel, resulting in strangulated intestinal obstruction, and emergency laparotomy was performed. During surgery, the ileum passed behind the elevated sigmoid colon in a caudal-to-cranial direction and formed an unusual closed loop. The strangulated part of the small intestine showed ischemic change; however, the intestine quickly normalized soon after strangulation was released, and the operation was completed without resection of the intestine. Discussion: The major cause of intestinal obstruction after colostomy is intraperitoneal adhesion. Looseness of the elevated sigmoid colon can cause internal hernia, if under pneumoperitoneum, when a colostomy is created through the extraperitoneal route in laparoscopic APR. Furthermore, the patient had lost more than 5 kg of body weight after the surgery, which may have led to the looseness of the elevated sigmoid colon. Conclusion: Releasing the pneumoperitoneum during the elevation of the sigmoid colon is necessary to prevent internal hernia, even with a colostomy performed through the extraperitoneal route.¹