Use of SPY Fluorescent Angiography to Reduce Ureteroenteric Stricture Rate Following Urinary Diversion

Overview

Ureteroenteric anastomotic stricture is a well-known complication of urinary diversion which occurs in 4-25% of patients. Recent study has yielded that radiation is a significant risk factor for development of ureteroenteric stricture. The goal of this study is to determine whether intraoperative use of SPY fluorescent angiography during urinary diversion reduces rate of ureteroenteric stricture. This study will include 215 patients who have undergone urinary diversion over the past 5 years as historic controls and compare ureteroenteric stricture rates to a prospective cohort of patients in whom intraoperative SPY fluorescent angiography was used at the time of urinary diversion to assess the anastomotic perfusion. This will include injection of ICG intravenously as well as utilization of the SPY device to assess ureteral perfusion before and after ureteroenteric anastomosis. Based on power analysis, this study will require approximately 50 patients in our prospective group to detect a clinically significant difference of 5% between groups. Data analysis plan includes the use of chi square test for comparison of stricture rates between groups. Clinical outcomes will be followed prospectively, with no amendment to standard follow-up per physician.

Ureteroenteric anastomotic stricture is a well-known complication of urinary diversion which occurs in 4-25% of patients. Strictures present clinically with flank pain, decreased renal function, pyelonephritis or may be asymptomatic and diagnosed incidentally with progressive hydronephrosis and renal impairment. Strictures are a cause of significant morbidity and health care expenditure, as treatment necessitates procedural intervention and often several inpatient admissions. Numerous studies have sought to identify risk factors for development of ureteroenteric strictures as well as opportunities for technical approaches to reduce stricture risk. Studies have demonstrated that Clavien-Dindo ≥ 3 complication and BMI were associated with higher risk of stricture. Ischemia of the anastomosis related to the tenuous ureteral blood supply is implicated in the formation of ureteroenteric stricture. Basic science and animal data have established the detrimental impact of radiation therapy on microvasculature. Radiation induced ureteral ischemia in conjunction with periureteral fibrosis make preservation of distal ureteral blood supply during urinary diversion tenuous and challenging. This is especially of concern in patients requiring pelvic exenteration for colorectal or gynecological malignancy, which often necessitate radiation therapy prior to surgical intervention. Radiation history is also an important contributor commonly in patients undergoing benign diversion for radiation cystitis. Several groups have tested whether varied surgical methods may offer risk reduction. Surgical anastomotic approach has not significantly impacted ureteroenteric stricture rate. However, a more recent study suggests that intracorporeal diversion confers a higher risk of ureteroenteric stricture. The gold standard for treatment of ureteroenteric stricture is open repair with ureteral reimplantation. Open surgical repair has success of 92-100%, while endoscopic management has success of 30-50%. A recent study demonstrated that through the use of indocyanine green (ICG) fluorescent angiography while performing urinary diversion using the DaVinci robotic system, that they were able to reduce stricture rates from 10.6% to 0%. Use of this technology allows the surgeon to evaluate the vascular supply to the ureter as well as the newly created ureteroenteric anastomosis. This significant reduction in complications has tremendous implications for improvement in patient care and reduction of morbidity. Many patients are not candidates for robotic urinary diversion and thus undergo open surgery. Fluorescent angiography has also shown promise for decreasing ureteroenteric stricture rate in open surgery.