Sarica K et al, 2015: Ureteral wall thickness at the impacted ureteral stone site: a critical predictor for success rates after SWL.
Sarica K, Kafkasli A, Yazici O, Cetinel AC, Demirkol MK, Tuncer M, Sahin C, Eryildirim B
Dr. Lutfi Kirdar Kartal Training and Research Hospital, Istanbul, Turkey
Abstract
The aim of the study was to determine the possible predictive value of certain patient- and stone-related factors on the stone-free rates and auxiliary procedures after extracorporeal shock wave lithotripsy in patients with impacted proximal ureteral calculi. A total of 111 patients (86 male, 25 females M/F: 3.44/1) with impacted proximal ureteral stones treated with shock wave lithotripsy were evaluated. Cases were retrieved from a departmental shock wave lithotripsy database. Variables analyzed included BMI of the case, diameter of proximal ureter and renal pelvis, stone size and Hounsfield unit, ureteral wall thickness at the impacted stone site. Stone-free status on follow-up imaging at 3 months was considered a successful outcome. All patients had a single impacted proximal ureteral stone. While the
mean age of the cases was 46 ± 13 years (range 26-79 years), mean stone size was 8.95 mm (5.3-15.1 mm). Following shock wave lithotripsy although 87 patients (78.4 %) were completely stone-free at 3-month follow-up visit, 24 (21.6 %) cases had residual fragments requiring further repeat procedures. Prediction of the final outcome of SWL in patients with impacted proximal ureteral stones is a challenging issue and our data did clearly indicate a highly significant relationship between ureteral wall thickness and the success rates of shock wave lithotripsy particularly in cases requiring additional procedures. Of all the evaluated stone- and patient-related factors,
only ureteral wall thickness at the impacted stone site independently predicted shock wave lithotripsy success.
Urolithiasis. 2014 Nov 25. [Epub ahead of print]
Comments 1
A nice idea. The overall ureteral wall thickness (UWT) was 3.28 ± 0.95 mm. In a multivariate analysis UWT and Hounsfield units of the stone predicted success. A cut-off value of UWT > 3.55 mm was highly predictive of additional procedures to reach a completely stone-free status.
The images accompanying the manuscript illustrate one problem to measure the ureteral wall thickness: the diameter of the ureteral wall is irregular and from the data given in the manuscript it is not clear where the measurements were taken.
Probably more work has to be done to introduce the ureteral wall thickness as a reliable parameter to predict SWL success in such cases.