Ureteral Wall Injury with Ureteral Access Sheaths: A Randomized Prospective Trial

Objective: To compare two commercially available ureteral access sheaths in their ability to access the renal collecting system and assess ureteral wall trauma using a prospective, randomized trial. Patients and Methods: Ninety-five patients undergoing ureteroscopy for renal stones were randomized to Cook Flexor™ or Boston Scientific Navigator HD™ 12/14F sheaths. If the initial sheath failed to advance, an alternate sheath was attempted. The primary outcome was the difference in these access sheaths to obtain access to the upper collecting system and the postoperative ureteral injury using standardized five-point classification system. Results: The overall success rate for sheath placement was 87.4% and did not differ for sheath groups. The Navigator HD was successful in 43% of the Flexor failures and was subjectively rated as easier to place (p = 0.018). Male gender, large stone burden, longer time of sheath insertion, and a more difficult subjective rating for sheath placement were associated with high-grade (grade 2 or 3) ureteral injury. Limitations include a small sample size and absence of long-term follow-up. Conclusion: Sheaths had equal success of placement and there was no significant difference in ureteral wall injury between the two sheaths. Subjectively difficult sheath placement and longer time of placement were associated with high-grade injury, suggesting that surgeons should carry a low threshold for switching to a smaller sheath when resistance is felt or if placement time is long.