Perirectal urinoma from ureteral injury incurred during spinal surgery mimicking rectal perforation on computed tomography scan.

STUDY DESIGN: A case of a perirectal urinoma from a ureteral injury incurred during spinal surgery is reported. OBJECTIVES: To report ureteral injury as a rare complication of spinal surgery with misleading CT findings, and to emphasize the necessity of delayed scans in the diagnosis. SUMMARY OF BACKGROUND DATA: A ureteral injury is a rare complication of spinal surgery. In such a case, extravasated urine collects in the retroperitoneum and pelvis. This fluid opacifies after intravenous contrast, and delayed scans are necessary in the diagnosis. As clinical findings are usually nonspecific, CT is essential for the correct diagnosis. METHODS: A 55-year-old woman underwent discectomy and insertion of a disc prosthesis through an anterior left retroperitoneal approach. Fever and abdominal pain developed after 3 days. Computed tomography scan was performed to evaluate the patient's symptoms. RESULTS: Computed tomography with repeated delayed scans showed an opacifying fluid collection surrounding the rectum, remote from the site of surgery, yet compatible with a urinoma. Antegrade pyelography demonstrated an injury of the left ureter with extravasating urine, dissecting caudally. After a temporary nephrostomy, the patient recovered. CONCLUSIONS: Although ureteral injury after abdominal surgery is not so uncommon, it is very rarely incurred during spinal surgery. Because symptoms are usually nonspecific, the radiologist should be aware of this possible complication, and should perform CT with intravenous contrast material and with delayed scans because a rapid-sequence helical CT may not yet show opacification of the fluid present in the abdomen. This is the hallmark of the diagnosis.