Extracorporeal Shock Wave Lithotripsy in Renal Stones; Evaluation of BMI, Hounsfield Units and Skin to Stone Distance as Predictive Factors

Abstract

E SWL was introduced more than three decades as authentic modern modality for the treatment of urinary stone disease. It is considered first choice of treatment for nearly all kind of urinary tract calculi. The outcome of ESWL for renal stones depends on many factors, including HU, SSD and BMI. Radiographic studies as NCCT has long been used clinically to evaluate causes of radiolucent filling defects by measuring the density of the substance in Hounsfield units to distinguish calculi from tumors or blood clots. Because it provides greater density discrimination than a conventional plain X-rays film. it is now the preferred method to evaluate patients with renal colic .In addition, it provides good information about the number of stones, the size, and skin to stone distance, as well as the presence or absence of any obstruction. The aim of this work was the evaluation of (HU, SSD and BMI) as single predictive factor or in combination on outcome of extracorporeal shock wave lithotripsy for adult patient with renal stone. In conclusion, the results of the present study confirmed that the use of NCCT for determining the attenuation values and SSD of renal calculi before ESWL helps to predict treatment outcome. A stone density of ≤ 970 HU and SSD ≤ 8.6 cm suggests a good chance of renal stone disintegration. The using above of this threshold could help to plan alternative treatment in patients with the likelihood of ESWL failure. BMI are independent factor of ESWL success prediction.