Obturator hernia: An uncommon cause of small bowel obstruction.

A 70 year old lady presented to surgery emergency with small bowel obstruction without any obvious etiology. On exploration she was found to have an obstructed obturator hernia, which is a rare pelvic hernia with an incidence of 0.07-1.4% of all intra-abdominal hernias. Diagnosis is often delayed until laparotomy for bowel obstruction. Strangulation is frequent and mortality remains high (25%). Early diagnosis and surgical treatment contributes greatly to reduce the mortality and morbidity rates. A variety of techniques have been described, however surgical repair has not been standardized. It is an important diagnosis to be considered in elderly patients with intestinal obstruction.

Introduction

Obturator hernia is a rare pelvic hernia with an incidence of 0.07%–1.4% of all intra-abdominal hernias [1] and accounts for 0.2%–5.8% of all mechanical small bowel obstruction cases. It has been found to predominantly affect elderly females.[2] Diagnosis is often delayed until laparotomy for bowel obstruction.[3] Strangulation is frequent and mortality remains high (25%–47.6%[45]). Primary closure of the hernia defect is difficult because adjacent tissues are not easily mobilized. A variety of techniques have been described, however surgical repair has not been standardized.

Case Report

A 70-year-old female presented to the surgical emergency with complaint of colicky pain in the whole abdomen along with bilious vomiting and abdominal distension for over 10 days. Physical examination revealed abdominal distension, exaggerated bowel sounds, absence of tenderness and rectal ballooning. There was no evidence of previous surgical scars or external hernias. Biochemical parameters were normal; however, the patient had evidence of previous healed pulmonary tuberculosis and emphysema on chest X-ray. Contrast-enhanced computed tomography abdomen of the patient revealed evidence of small bowel obstruction, but no obvious etiology. Thus, the patient was taken for emergency laparotomy via midline vertical incision. Upon exploration, she was found to have left-sided obstructed Richter-type obturator hernia [Figure 1] with tip of involved bowel having questionable vascularity. The hernia sac was thus approached via upper medial thigh incision and reduced [Figure 2]. Resection anastomosis of the involved segment was done along with preperitoneal mesh plug repair of hernial orifice. The patient was shifted to the Intensive Care Unit for ventilatory support. She developed ventilator-associated pneumonia and expired on postoperative day 7. During the survival, there was no evidence of wound dehiscence or anastomotic breakdown.

Figure 1

Left-sided obstructed Richter-type obturator hernia discovered upon exploratory laparotomy

Figure 2

Hernial sac and incarcerated bowel seen after reduction

Discussion

Obturator hernia is an extremely uncommon pelvic and intra-abdominal hernia. The hernia sac protrudes via obturator foramen located in the anterolateral pelvic wall bilaterally. It is characteristically seen in elderly derelict females. The female predominance has been contributed to pregnancy, which causes relaxation of the pelvic peritoneum and a wider and more horizontal obturator canal.[6] This hernia is seen thrice more often on the right side than the left, along with a rare but well-documented, concurrence of bilateral as well as femoral hernias.[7] Hernia is asymptomatic till bowel obstructs and presents with acute or intermittent small bowel obstruction. In a typical case, the patient may complain of pain along the medial aspect of thigh exacerbated by the movement of hip or thigh consequent to compression of obturator nerve.[1] This Howship–Romberg sign is found in only 15%–50% cases.[8] Another, Hannington-Kiff sign (absent adductor reflux in the thigh) is more specific but much less commonly seen.[8] Various investigation modalities employed to assist diagnosis include ultrasonography, herniography, and computed tomography (CT) of the abdomen. CT scan of the abdomen has maximum specificity and sensitivity [8] and is recommended for the suspected obturator hernia and intestinal obstruction without obvious cause. The accuracy of CT scan in diagnosing obturator hernia is approximately 90%,[910] higher with strangulated hernias. It may reveal small bowel loops behind the pectineus muscle, air in the under pubic channel.[2]

For acute presentation, midline infraumbilical vertical approach is preferred, while other approaches such as retropubic, preperitoneal, groin or laparoscopic approaches may be used if hernia is diagnosed preoperatively. The laparoscopic surgery has the advantages of less postoperative pain, shorter hospital stay and lower complications but is reserved for the nonstrangulated hernia. Both transabdominal and extraperitoneal approaches have been described with transabdominal approach preferred for the emergency setting.[11] Very often obturator hernia is detected during totally extraperitoneal (TEP) repair for inguinal hernias. This reflects the importance of inspecting all the myopectineal orifices during the TEP approach to allow for the diagnosis and repair of asymptomatic obturator hernias.[12]

The author concludes that obturator hernia is an important diagnosis to be considered in elderly patients with intestinal obstruction. Early diagnosis and surgical treatment contribute significantly to reduce the mortality and morbidity rates.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.