Incarcerated obturator hernia: pitfalls in the application of ultrasound

Objective To describe ultrasonographic appearance and diagnoses of incarcerated obturator hernia. Methods Three consecutive cases of incarcerated obturator hernia examined preoperatively with ultrasound were presented to show the pitfalls in the application of ultrasound for the recognition of the entity. Retrospectively reviewed, ultrasound directly demonstrated an incarcerated obturator hernia in all the cases. Results The herniated segment was delineated posterior to the pectineus muscle in the femoral triangle. However, the sonographer mistakenly interpreted it showed a femoral hernia in the first case. In the third case, the sonographer did not scan the femoral regions in the initial examination although he confirmed the evidence of small bowel obstruction. The evidence of an incarcerated obturator hernia was detected in the re-examination with ultrasound after it had been revealed by CT scan. Consequently, ultrasound was evaluated as applicable and useful for the recognition of incarcerated obturator hernia. Conclusion Ultrasound is an useful tool for detecting obturator hernia. However, adequate education and training for examiners are required to prevent false interpretation or overlooking of the entity.