"Blind coning"--using the Stone Cone for removal of intramural ureteral calculi

To describe the otherwise heretical technique of "blind" nonureteroscopic extraction of calculi from the intramural ureter using a 7-mm-diameter tapered coil called the "Stone Cone."

After bypassing the stone and deploying the Stone Cone, slow traction was exerted. The Stone Cone's 5, 6, and 7-mm diameter coils and unique rotary action dilated the tunnel distal to the calculus and the 2, 3, and 4-mm stiffer coils caught the calculus and propelled it out of the transiently dilated intramural ureter. A safety feature is that the coils of the Stone Cone will unwind at greater than 0.2-lb tension. Unlike the baskets, if a pressure greater than this is encountered, the Stone Cone will release the stone, preventing entrapment.

In selected cases, use of the Blind-Cone to remove an intramural calculus can be a rapid, effective, and safe alternative to ureteroscopic management.