Endopyelotomy sheath: a new device to facilitate antegrade endopyelotomy

Antegrade endopyelotomy is still the treatment of choice in most cases of ureteropelvic junction obstruction. In this approach using the standard technique the cold knife incision invariably falls in a different plane, which may result in a thin strip of ureteral mucosa and at times avulsion as well as difficult passage of the endopyelotomy stent. A modified technique using a new device has been studied to augment safety and the precision of incision at the ureteropelvic junction during endopyelotomy.

The endopyelotomy sheath is a 22 cm. hollow polyurethane tube with a proximal size of 7 cm. that is 12Fr to 16Fr, tapering to 6Fr distally. This sheath is passed over a single guide wire and advanced under fluoroscopic guidance until the wider proximal end is placed across the ureteropelvic junction. The proximal end has a slit that is directed at the incision site and through which an incision is made with a cold knife.

To date this modified technique has been used in 16 patients. The sheath provided good space for making an incision and made the movement of the knife safe and much easier. The incision was smooth and always made at 1 place, ensuring the preservation of the maximum circumference of the mucosa across the ureteropelvic junction. Mean function +/- SEM was 36.18% +/- 6.14% (range 27% to 48%) and mean pelvic volume was 44 ml. (range 34 to 60). At a mean followup of 10 months (range 3 to 17) 14 patients (87.5%) showed objective improvement.

This endopyelotomy sheath simultaneously dilates the ureteropelvic junction and allows a smooth cut in a straight line at a predetermined site. By this maneuver the maximum circumference of mucosa is preserved for better healing and possibly better results. Passing the endopyelotomy stent was not a problem. This sheath makes endopyelotomy safe, easy and user friendly.