[Predictive factors of successful treatment of lower caliceal calculi with Edap LT02 extracorporeal lithotripsy].

OBJECTIVE: To determine the predictive factors of success of extracorporeal shock-wave lithotripsy (ESWL) for lower caliceal stones.

PATIENTS AND METHODS: The case files of 100 patients with a single stone in the lower pole of the kidney, ranging in size from 6 to 25 mm, treated by EDAP LTO2 extracorporeal lithotripsy between 1994 and 1997, were studied. Pretreatment intravenous urography was reviewed to assess the characteristics of the stone, to measure the pyelocaliceal angle and to study the anatomy of the lower pole of the kidney.

RESULTS: The overall stone-free rate at 3 months was 57%. The success rate was 67.18% for stones smaller than 1 cm and 38.88% for stones larger than 1 cm. Stones denser than bone were successfully treated in 45.5% of cases, those less dense than bone were successfully treated in 71.11% of cases. The success rate was 86.04% when the pyelocaliceal angle was greater than 90 degrees and 35.08% when this angle was less than 90 degrees. The stone-free rate was 75% when the caliceal stalk was less than 3 cm and 37.5% when the stalk was greater than 3 cm.

CONCLUSION: In this series, the size of the stone, its density, the pyelocaliceal angle and the length of the caliceal stalk were predictive elements of the success of ESWL for lower caliceal stones. The pyelocaliceal angle was the most significant factor. A very dense stone on the plain abdominal film with a diameter of 1 cm or more and presenting unfavourable anatomical factors should be treated by percutaneous nephrolithotomy as the first-line procedure.