Incidental detection of bowel herniation with ultrasonography and fluoroscopy during a caudal block

In contrast to fluoroscopy, ultrasonography allows visualization of structures such as muscles, tendons, vessels, and nerves. We describe a case where ultrasonography in conjunction with fluoroscopy led to the incidental diagnosis of bowel herniation in a patient undergoing a caudal block.

A 71-yr-old woman presented to our chronic pain clinic with a long-standing history of coccydynia for which she had undergone a partial coccygectomy. A trial caudal block was planned. Fluoroscopy of the lower sacral area revealed the presence of a gas bubble inferoposteriorly to the coccygeal remnant. A confirmatory ultrasound scan revealed a hollow structure compatible with bowel. The procedure was abandoned. Subsequently, a non-enhanced computed tomographic scan of the pelvis confirmed the diagnosis of large bowel herniation. The patient was referred to a colorectal surgeon, and she subsequently underwent successful laparoscopic repair of the coccygeal hernia.

Ultrasonography can be a valuable adjunct in identifying non-neural pathologies in patients undergoing interventional procedures in chronic pain management. This case report highlights the importance of being vigilant for unanticipated pathologies during ultrasound examinations while performing chronic pain block procedures.