Spontaneous interparietal posterior rectus sheath hernia presenting as small bowel obstruction in a virgin abdomen: a case report

Abstract

Spontaneous posterior rectus sheath/interparietal hernias are exceedingly rare, with only a limited number of case reports published in the literature, particularly in patients without history of prior abdominal surgery. They may present diagnostic difficulty because the herniated bowel can remain contained within the abdominal wall layers without an obvious external bulge. We report a 65-year-old woman with hypertension and asthma, with prior hysterectomy via a transvaginal approach and no prior abdominal surgery, who presented with one day of abdominal pain, nausea, vomiting, and more than 24 hours of obstipation. Laboratory evaluation showed leukocytosis of 13.3×10⁹/L, with otherwise unremarkable chemistry and coagulation studies. CT demonstrated small bowel obstruction secondary to a right upper abdominal wall hernia, with a short segment of small bowel herniating between the transversus abdominis and rectus abdominis muscles, mild upstream dilation, small bowel feces sign, and reactive simple fluid in the hernia sac. Given persistent obstruction despite initial nonoperative management, the patient underwent operative exploration. The incarcerated small bowel was reduced from an obstructed interparietal abdominal wall hernia. The bowel was viable after reduction, and no resection was required. The hernia sac was excised and the fascial defect was closed. This case highlights a rare cause of small bowel obstruction in a virgin part of the abdominal wall and emphasizes the importance of careful CT review for deep abdominal wall hernias.