EP2033 - Surgical Management of a Ureterocolic Fistula

Purpose/Background: Diverticular disease is a common condition, particularly prevalent in the aging population, with approximately 60% of individuals over 60 years affected. While most cases remain asymptomatic or uncomplicated, 4-5% of patients may develop diverticulitis, and a subset of these cases can further progress to complicated diverticular disease. Among these complications, fistula formation is well recognized, with colovesicular and colovaginal fistulas being the most frequently encountered. Ureterocolic fistulas, by contrast, represent a significantly rarer and underreported entity, often posing substantial diagnostic and management challenges due to their anatomic location and overlapping clinical presentation with other more common fistulas. Here, we present a case of a ureterocolic fistula, highlighting the diagnostic challenges and surgical considerations in management.

Methods/Interventions: We present the case of a female patient in her 60s with a known history of recurrent diverticulitis, who was referred to our clinic for evaluation of a suspected colovesicular fistula. She reported a three-month history of intermittent lower abdominal pain and pneumaturia. Initial imaging with contrast-enhanced CT of the abdomen and pelvis revealed intraluminal air within the bladder and an apparent communication at the left posterolateral bladder wall. Colonoscopy was attempted but was unsuccessful due to severe diverticulosis and significant angulation of the sigmoid colon, limiting visualization. Based on clinical and radiographic findings, she was scheduled for robotic-assisted sigmoid colectomy with presumed fistula takedown.

Intraoperatively, the bladder was thoroughly inspected and found to be uninvolved. However, dense inflammatory adhesions were noted between the sigmoid colon and the left pelvic sidewall, raising suspicion for a ureterocolic fistula. Intraoperative urology consultation was obtained. Cystoscopy and left ureteral stent placement were performed to identify and protect the ureter. The left ureter was carefully dissected and preserved during mobilization of the sigmoid colon. A sigmoid colectomy with primary colorectal anastomosis was performed without complication.

Results/Outcomes: The patient recovered well postoperatively, with return of bowel function by postoperative day three and was subsequently discharged. The ureteral stent was removed six weeks later following confirmation of ureteral integrity via antegrade pyelogram, which showed no contrast extravasation. At follow-up, the patient reported complete resolution of her preoperative symptoms, including abdominal pain and pneumaturia, and had normal bowel and urinary function.

Conclusion/Discussion: This case underscores the diagnostic difficulty of ureterocolic fistulas, which may mimic more common fistulas such as colovesicular due to overlapping symptomatology and nonspecific imaging findings. CT imaging remains the most sensitive modality; however, definitive diagnosis is often only made intraoperatively. Awareness of this rare complication is critical, especially in patients with chronic diverticular disease and atypical presentations. Collaboration with urology and intraoperative stenting can be essential tools in preventing ureteral injury and optimizing surgical outcomes.

Given the scarcity of reported cases in the literature, our experience contributes valuable insight into the successful multidisciplinary surgical management of this rare and complex condition.

Intraoperative image 1
Ureterocolic fistula during dissection
Intraoperative image 2
After ureterocolic fistula takedown and sigmoid colon resection