Obstructive Pyelonephritis Due to Postoperative Ureteral Stricture: A Case Report

Iatrogenic ureteral injury is an uncommon but potentially severe complication of abdominopelvic surgery. When not identified intraoperatively, it may present days to weeks later with flank pain, fever, urinary tract infection, and imaging evidence of obstruction. Early recognition and timely urinary diversion are essential to prevent sepsis and preserve renal function. A 65-year-old patient underwent elective resection of an abdominal mass; pathology confirmed schwannoma. On postoperative day 15, the patient developed left flank pain and fever. Laboratory tests showed leukocytosis (WBC 15,000/mm³) and elevated C-reactive protein (150 mg/L); urine culture grew Escherichia coli. Contrast-enhanced CT demonstrated left hydronephrosis without stones, suggesting postoperative ureteral obstruction. Retrograde double-J stenting was attempted but failed. Urgent percutaneous nephrostomy achieved decompression with clinical improvement under targeted antibiotics. Definitive exploration revealed a 1 cm stricture of the lumbar ureter, managed by segmental resection and tension-free spatulated termino-terminal ureteroureterostomy over an internal stent. Postoperative recovery was uncomplicated; the stent was removed after 3 weeks. Follow-up ultrasound showed no persistent pelvicalyceal dilatation. Delayed ureteral obstruction should be suspected in postoperative patients presenting with flank pain, fever, and hydronephrosis. When retrograde stenting fails in the setting of infection, percutaneous nephrostomy provides rapid decompression and source control, allowing delayed definitive reconstruction. For short-segment proximal or mid-ureter strictures, ureteroureterostomy remains a reliable option when performed according to reconstructive principles.