Department for Urology, University of Heidelberg, Heidelberg, Germany.
Study Type - Therapy (case series) Level of Evidence 4.
To investigate the effect of different variables including body mass index (BMI) on therapy outcome in patients with upper urinary tract stones treated with a third generation lithotripter, as BMI has been reported to be an independent predictor for stone-free status after extracorporeal shockwave lithotripsy (SWL) performed with first or second generation lithotripters.
In all, 172 patients with kidney stones with a mean (range) size of 9.2 (3.0-32.0) mm were included in the study. In all, 91 patients (52.9%) were treated with a ureteric stent in situ. For SWL therapy a third generation, electromagnetic lithotripter (Siemens Lithoskop(TM) ) was used. Stone-free status was reached, when no more treatable stones were present (no stone or stone < 3 mm). BMI, stone size and localization, age, gender, treatment parameters and ureteric stent in situ were evaluated for their prognostic relevance on therapy success.
The mean (range) BMI of all patients was 27.8 (19.0-58.6) kg/m(2) . Patients were categorized into two groups: A) patients that were stone free after one treatment; B) patients with residual stones. The mean (sd) BMI was 27.4 (4.6) kg/m(2) and 28.4 (6.1) kg/m(2) for A and B, respectively. Univariate and multivariate analysis for freedom of stones showed that only stone size (P < 0.01) and presence of a ureteric stent (P= 0.01) were independent prognostic variables. BMI had no significant influence on therapy outcome (P= 0.51).
Using a third generation lithotripter, BMI was not an independent predictor of stone-free rate after SWL therapy of kidney stones. This effect might be attributed to a greater penetration depth of the shockwave energy. Stone size and a ureteric stent in situ were the only variables with prognostic significance.
Written by:
Hatiboglu G, Popeneciu V, Kurosch M, Huber J, Pahernik S, Pfitzenmaier J, Haferkamp A, Hohenfellner M.
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Reference: BJU Int. 2011 Feb 22. Epub ahead of print.
doi: 10.1111/j.1464-410X.2010.10007.x
PubMed Abstract
PMID: 21342413
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