Image of the Month—Diagnosis

Exploratory laparotomy was performed. A left-sided obturator hernia was identified containing a segment of midjejunum. The hernia defect was approximately 1.5 cm (Figure 2). The hernia contents and peritoneal sac were reduced, and a necrotic segment of jejunum was resected. An extraperitoneal mesh repair was performed using a Surgisis Gold Hernia Repair Graft (Cook Biotech Incorporated, West Lafayette, Ind).

Obturator hernia accounts for 0.2% to 0.4% of bowel obstructions. The obturator canal is the largest foramen in the pelvis and is located at the anterior superior border of the obturator foramen. Coursing through the canal are the obturator nerve, artery, and vein with preperitoneal fat. The hernia occurs frequently in elderly, debilitated women because of the loss of the protective fat pad.^1,2The incidence is higher in women than men because of the broader pelvis and larger obturator canal.^3,4Since the sigmoid colon acts as an anatomical barrier, right-sided herniations are more common.

Presenting symptoms are nonspecific and physical findings are usually vague.¹Patients with a symptomatic obturator hernia often present with partial or complete bowel obstruction. Two classic signs have been associated with this type of hernia. Howship-Romberg sign is pain that extends down the medial aspect of the thigh with abduction, extension, or internal rotation of the knee due to irritation of the anterior division of the obturator nerve. It is present in 25% to 50% of patients.^5-7Hannington-Kiff sign, which is more specific but less known, is ipsilateral loss of the thigh adductor reflex with preservation of the patellar reflex due to external nerve compression.⁸

Successful diagnosis can be achieved with high clinical suspicion and emergent CAT scan. A CAT scan appears to be the most valuable imaging modality aiding in the preoperative diagnosis and it is 100% accurate.⁷

Various surgical approaches, such as femoral, inguinal, and abdominal, have been reported in the literature. The abdominal approach is most favored since the preoperative diagnosis may be unclear and incidence of bowel compromise is high.^7,9,10

Correspondence:Rodney J. Mason, MD, PhD, Department of Surgery, University of Southern California, 1200 N State St, 10850, Los Angeles, CA 90033 (rmason@surgery.usc.edu).

Accepted for Publication:June 28, 2006.

Author Contributions:Study concept and design: Estrada, Petrosyan, and Mason. Acquisition of data: Estrada, Petrosyan, and Mason. Analysis and interpretation of data: Estrada, Petrosyan, and Mason. Drafting of the manuscript: Estrada, Petrosyan, and Mason. Critical revision of the manuscript for important intellectual content: Estrada, Petrosyan, and Mason. Administrative, technical, and material support: Estrada, Petrosyan, and Mason. Study supervision: Estrada, Petrosyan, and Mason.

Financial Disclosure:None reported.