The safety wire with a ureteral access sheath - does it hurt more than it helps?

Studies indicate that with a safety wire in the ureter, an increased amount of force is necessary to advance ureteral access sheaths up to the proximal ureter. Theoretically, the compression of the ureter with the wire could lead to an increase in number and severity of ureteral injuries secondary to placement of a sheath. This prospective study aims to evaluate if there is a correlation between the use of a safety wire and ureteral injury from sheath placement by evaluating the location of the wire in relation to the injury after ureteroscopy.

Fifty-nine consecutive patients underwent ureteroscopy for upper tract urinary stone disease. A 12/14 French ureteral access sheath was used with a safety wire in place. Ureteroscopy during withdrawal of the sheath was video recorded and reviewed by a blinded observer. Visible ureteral injuries were graded per the Traxer ureteral injury scale and the proximity of the wire to the injury was noted.

Thirty-one of 59 patients (52.4%) had a ureteral injury secondary to access sheath placement. Eighteen (30.5%) injuries were low-grade, 13 (22.0%) were high-grade (grade 2 and 3) and there were no grade 4 injuries. A total of 10 (32.3%) injuries occurred on the same side as the wire while 67.7% were on the contralateral side of the ureter. Of the injuries that occurred on the same side as the wire, 80% were grade 1 injuries and 2 (20%) were grade 3. Statistical analysis did not show a significant relationship between high/low injury grade and side of injury (p value = 0.088). This suggests that there is no association of between the safety wire and development of high injury.

There is no association between the location of the safety wire and ureteral injury if injury occurs during the placement of a ureteral access sheath. This suggests that the use of a safety wire does not add significant morbidity to the procedure.