Body mass index and buttock circumference are independent predictors of disintegration failure in extracorporeal shock wave lithotripsy for ureteral calculi.
OBJECTIVE
Effective stone disintegration by extracorporeal shockwave lithotripsy (ESWL) may depend on patient- and stone-related factors. We investigated predictors of disintegration failure in ESWL for a solitary ureteral calculus.


METHODS
From July 2008 to May 2010, 203 patients who underwent ESWL for a solitary ureteral calculus were enrolled. Clinical and radiologic data were collected, and factors related to ESWL failure were analyzed.


RESULTS
Fifty-two patients (25.6%) showed ESWL failure, with a mean follow-up of 41 days. Forty patients (19.7%) required retreatment, including 12 who underwent repeat ESWL and 28 who underwent curative ureteroscopy. Patients with ESWL failure had significantly higher body weight, body mass index (BMI), and buttock circumference (BC) than patients for whom ESWL was successful. Univariate analysis showed that stone burden (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.03-1.06) and BC (OR, 1.06; 95% CI, 1.01-1.11) were predictors of ESWL failure, while BMI was a potential predictor with borderline significance (OR, 1.09; 95% CI, 0.99-1.20). Multivariate analysis showed that stone burden (OR, 1.04; 95% CI, 1.03-1.06) was a significant predictor for all patients. On stratifying patients according to the level of ureteral calculi, BC was found to be an independent predictor (OR, 1.35; 95% CI, 1.02-1.80) for ESWL failure for middle/lower ureteral calculi and BMI (OR, 1.47; 95% CI, 1.13-1.91) for upper ureteral calculi.


CONCLUSIONS
Stone burden is the main predictor of ESWL failure for all patients with ureteral calculi. BC and BMI are independent predictors for ESWL failure for middle/lower and upper ureteral calculi, respectively.
Department of Surgery, Yonghe branch, Cardinal Tien Hospital, New Taipei City, Taiwan.
Teng-Kai
TK
Yang
Hung-Ju
HJ
Yang
Liang-Min
LM
Lee
Chun-Hou
CH
Liao
D015992:Body Mass Index; D002081:Buttocks / Q000033:anatomy & histology*; D006801:Humans; D008096:Lithotripsy; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D017211:Treatment Failure; D014514:Ureteral Calculi / Q000628:therapy*; D018666:Ureteroscopy
disintegration; extracorporeal shock wave lithotripsy; predictor; ureteral calculi