Independent predictors of failure of shockwave lithotripsy for ureteral stones employing a second-generation lithotripter.
OBJECTIVE
To define factors associated with the failure of shockwave lithotripsy (SWL) in the treatment of ureteral stones.


METHODS
We retrospectively studied 405 men and 283 women (mean age 52.6 years) who underwent SWL with a second-generation lithotripter in the period 1994 to 2001. We evaluated available clinical and radiologic features that might have been related to failure of SWL therapy.


RESULTS
Treatment was successful in 502 patients (73%). The 186 patients (27%) in whom treatment failed underwent endourologic alternatives or open surgery. Multivariate logistic regression analysis revealed that unsuccessful outcome was significantly related to: (1) pelvic ureteral stones (odds ratio [OR] 4.02; 95% CI 1.97, 8.19); (2) stone size >10 mm (OR 3.46; 95% CI 2.16, 5.53); (3) obstruction (OR 1.93; 95% CI 0.99, 3.77); and (4) obesity (OR 1.87; 95% CI 0.95, 3.77). Although the predictive value of each individual parameter was relatively low (15.3%-27.9%) the cumulative risk was 82.95% when patients had all four features. The strongest independent predictors of failure were pelvic stones and stones >10 mm (cumulative predictive value 57.3%).


CONCLUSIONS
These variables may enable identification of a subgroup of patients who will fail initial SWL. These patients may be candidates for endourologic alternatives as first-line treatment.
Delakas
Dimitrios
D
Department of Urology, General University Hospital, Heraklion, Crete, Greece. delakas@mail.gr
Karyotis
Ioannis
I
Daskalopoulos
George
G
Lianos
Emmanuel
E
Mavromanolakis
Emmanuel
E
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D004724:Endoscopy; D005260:Female; D006801:Humans; D007682:Kidney Pelvis / Q000473:pathology*; D008096:Lithotripsy; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000150:complications; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects; D017211:Treatment Failure; D014514:Ureteral Calculi / Q000473:pathology* / Q000628:therapy*; D014517:Ureteral Obstruction / Q000150:complications*