A modification of the Otis urethrotome as an aid to fascial dilation of percutaneous nephrostomy tracts.

An Otis urethrotome has been modified by drilling a 3/64-inch hole through the tip to permit passage into the kidney over a 0.038-inch guide wire. This instrument has been used to aid in the performance of 12 nephrostomy tract dilations without significant complications. When compared to 10 Amplatz tract dilations, the modified Otis method required an average of 3.6 minutes versus 8.7 minutes to dilate the nephrostomy tract to 24F. Ease of tract dilation as well as decreased time to dilate make this technique a useful adjunct to standard nephrostomy tract dilation techniques.