[Results of extracorporeal lithotripsy with ultrasonography-guided hydroelectric lithotriptor: study on 546 patients, prognosis factors].
OBJECTIVE
To investigate the existence of simple radiographic prognostic criteria, applicable on an outpatient basis, predictive of the result of extracorporeal lithotripsy (ECL).


METHODS
This study was based on 546 patients treated by ECL using a hydroelectric apparatus. The results were evaluated on plain nephrotomographies and ultrasonography performed at the third month. Success was defined as the elimination of all residual fragments, regardless of their size, without fragments (WF). Analysis concerned 485 files after exclusion of patients lost to follow-up. Prognostic factors were evaluated criterion by criterion, and then by multiple ascending regression multivariate analysis.


RESULTS
The fragment-free rate according to our criteria was 57.5%. Significantly poorer results were obtained for stones denser than bone (p < 0.001), smooth (p < 0.001, larger than 12 mm (p < 0.01), situated in the inferior calyx (p < 0.005), despite an increased (p < 0.005) number of ECL sessions and the number of shocks received. A correlation was established between the radiographic appearance of the stone, its predominant spectrophotometric nature (> or = 50%) and the results of ECL. Good results were obtained in 65% of spiculated, low-density Weddellite stones versus 41% of cases of dense, smooth Whewellite stones. Multivariate analysis of the predominant radiographic appearance of the stones showed that spiculated, low-density stones were completely eliminated in 79.4% of cases, and dense, smooth stones were completely eliminated in 33.6% of cases (p < 0.001).


CONCLUSIONS
In this study, smooth, dense stones larger than 12 mm, situated in the inferior calyx appear to be particularly resistant to ECL. On the basis of this result, the authors propose a prospective clinical trial to compare the results of ECL and primary percutaneous nephrolithotomy in this type of stone with a high risk of failure.
Bon
D
D
Service d'Urologie, CHRU Poitiers.
Doré
B
B
Irani
J
J
Marroncle
M
M
Ingrand
P
P
Aubert
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging / Q000628:therapy*; D008096:Lithotripsy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D014463:Ultrasonography; D014514:Ureteral Calculi / Q000000981:diagnostic imaging / Q000628:therapy*