Waqas M et al, 2018: Evaluating the importance of different computed tomography scan-based factors in predicting the outcome of extracorporeal shock wave lithotripsy for renal stones.
Waqas M, Saqib IU, Imran Jamil M, Ayaz Khan M, Akhter S.
Department of Urology, Shifa International Hospital, Islamabad, Pakistan.
Foundation Year Resident, Shifa International Hospital, Islamabad, Pakistan.
Abstract
Purpose: To evaluate the impact of various computed tomography scan-based parameters of renal stones on the outcome of extracorporeal shock wave lithotripsy (ESWL).
Materials and Methods: We conducted a retrospective study of patients who underwent ESWL for renal stones (sized 5–20 mm) from January 2013 to December 2016. We evaluated body mass index, location of the stone, skin-to-stone distance (SSD), stone attenuation value (SAV), stone diameter, Hounsfield density, stone area, and stone volume. Statistical analysis was done and significance was confirmed by multivariate logistic regression analysis.
Results: Of the 203 patients 122 (60.1%) had successful clearance of the stone. The presence of a double J stenting, a lower pole location, a higher SAV, higher Hounsfield density, larger stone area, larger stone diameter, and higher stone volume were negative predictors of ESWL outcome. When these parameters were analyzed with multivariate logistic regression analysis, stone location, SSD, and SAV were the only significant independent predictors of the outcome of ESWL.
Conclusions: Stone location, SSD, and SAV are reliable and strong predictors of ESWL outcome for the treatment of renal stones.
Investig Clin Urol. 2018 Jan;59(1):25-31. doi: 10.4111/icu.2018.59.1.25. Epub 2017 Dec 28. FREE ARTICLE
Comments 1
There are many studies on the market looking at parameters that allow predicting the success rate of ESWL based on imaging findings. But important details having a decisive influence on the results are most frequently not reported. In the present study, they “used a Modulith SLX lithotripter (4th generation; STORZ Medical Equipment, Tägerwilen, Switzerland) for ESWL.” and “The number of shock waves and energy settings were decided by the physician. A maximum of 4,000 shock waves were administered at a maximum power of 18 kV. During ESWL, pain was managed with intravenous nalbuphine. The stones were fragmented under fluoroscopic or ultrasound guidance.”
This is just the standard description of an ESWL series. I do not criticize the authors for adhering to these publication customs but a report on the success rates of ESWL nowadays should include data on how the rules of a good ESWL technique were followed (Aspects on how extracorporeal shockwave lithotripsy should be carried out in order to be maximally effective. Tiselius HG, Chaussy CG. Urol Res. 2012 Oct;40(5):433-46) Editors and reviewers should consider these aspects when accepting a paper for publication.