Obturator hernia: the ‘little old lady's hernia’
First described by Arnaud de Ronsil in 1724, OH accounts for 0.05–0.4% of all hernias1 and 0.2–1.6% of all cases of mechanical bowel obstruction.2 The obturator foramen is the strongest and largest foramen in the body. It is a large oval opening in the hipbone bound by the pubis, ischium and the pubic rami. This foramen is closed by a thin but strong obturator membrane. The obturator nerve, artery and vein pass via a small passageway through this membrane. The presence of this foramen reduces the bony weight of the pelvis and the strong membrane provides a surface for the attachment of muscles. Weakness of this membrane allows for bowel to herniate through this foramen resulting in mechanical bowel obstruction. The hernial sac passes through several layers during the process of herniation, these include the obturator internus muscle fibres, obturator membrane and the obturator externus muscle fibres.
A 73‐year‐old female presented to the emergency department (ED) with small bowel obstruction (SBO) thought to be secondary to adhesions. Computerized tomography (CT) scan showed a right OH containing a loop of small bowel. The patient underwent an immediate laparotomy, which showed an ischaemic loop of small bowel in the OH sac requiring resection. The defect was greater than a centimeter in diameter. The ischaemic loop of small bowel ruptured during reduction from the hernia sac, resulting in faecal contamination. Hence, mesh was not used. After an extensive washout of the peritoneal cavity, the uterus was mobilized and sutured circumferentially to occlude the defect. The patient had an uneventful post‐operative period and was discharged home on day 5.
The second case was an 88‐year‐old lady who presented to the ED with symptoms of SBO with numbness over the left thigh ongoing for the past 3 days and nausea and vomiting for the last 24 h. The patient's primary concern was the left thigh numbness, which had progressed to a weakness in that area. Past history revealed Caesarian section, hypertension and type two diabetes. A plain abdominal X‐ray revealed a SBO. On examination, she elicited a positive Howship–Romberg sign with typical paresthesia over the medial thigh region. A CT scan was performed immediately confirming an OH. The patient underwent a laparotomy, which showed an ischaemic loop of small bowel herniating through the obturator foramen, requiring resection. The OH defect was less than a centimeter in diameter and was occluded by mobilizing and fixating the left ovary. The patient recovered uneventfully and was discharged home on day 3.
The third case was a 48‐year‐old multiparous woman, presenting to the ED with left thigh paresthesia with intermittent pain. There were no signs of SBO on presentation. The patient was otherwise well with no significant medical conditions. An active woman, she noticed difficulty with her daily exercises. An ultrasound of her groin demonstrated a left OH containing extra‐peritoneal fat. The patient underwent a laparotomy using a Pfannensteil incision, and using an extra‐peritoneal approach, the hernia contents along with the sac were reduced. The defect was repaired with a polypropylene mesh plug anchored with non‐absorbable sutures. The patient had an uneventful recovery with immediate resolution of her symptoms and was discharged home the following day.
OH typically occurs in multiparous, elderly and emancipated women with raised intra‐abdominal pressure with history of recent weight loss.