The lithotripsy table height: a novel predictor of outcome in shockwave lithotripsy
Int. braz. j. urol
;
37(3): 355-361, May-June 2011. ilus, graf, tab
Article
in English
| LILACS
| ID: lil-596010
ABSTRACT
BACKGROUND:
Outcome of Extracorporeal Shockwave Lithotripsy (SWL) is determined by physical factors that affect stone fragmentation and clearance.PURPOSE:
To evaluate the predictive value of the Lithotripsy Table Height (LTH) in SWL outcome. Lithotripsy Table Height (LTH) is a variable that represents skin to therapy head distance, and it is proportional to the energy that reaches the stone. MATERIALS ANDMETHODS:
A prospective study enrolled patients undergoing SWL for radiopaque urinary stones. All procedures were performed using a Modulith SLX (Karl Storz, Germany) Lithotripter. Patient weight, height and age; stone location and size; number of shock waves delivered, and LTH were recorded. One month post-procedure a KUB was obtained. Logistic regression analysis was used to evaluate the effects of these variables on stone-free outcome. A ROC curve was plotted.RESULTS:
Fifty-six patients were enrolled. After one month follow-up, overall success rate (Stone Free) was 83.9 percent (n = 47). LTH was the only independent predictor of outcome in both univariate and multivariate analysis (p = 0.029). Stone size (p = 0.45) and BMI (p = 0.32) were not significant. In the ROC curve, LTH showed an Area under the Curve = 0.791. Patients with LTH < 218 (n = 8) had relative risk of residual stones = 7.5, odds Ratio 6.6 (Stone free rate 37.5 percent vs. 91.5 percent).CONCLUSION:
LTH appears to be an independent predictor of SWL outcome. High success rates can be expected if LTH > 218. Patients with lower LTH had a less effective therapy, therefore, worse stone fragmentation and clearance. These findings may help improve patient selection for SWL therapy.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Lithotripsy
/
Urinary Calculi
/
Operating Tables
Type of study:
Diagnostic study
/
Etiology study
/
Evaluation studies
/
Observational study
/
Prognostic study
/
Risk factors
Limits:
Adult
/
Female
/
Humans
/
Male
Country/Region as subject:
South America
/
Chile
Language:
English
Journal:
Int. braz. j. urol
Journal subject:
Urology
Year:
2011
Type:
Article
Affiliation country:
Chile
Institution/Affiliation country:
Universidad de Chile/CL
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