Salvi M. et al., 2020: Active treatment of renal stones in Pelvic Ectopic Kidney: systematic review of literature
Purpose: To identify the role of Doppler US (DUS) in the prediction of factors affecting stone-clearance post-SWL for ureteral stones in addition to its role in prediction of pretreatment stone impaction.
Methods: We prospectively included patients with ureteric stone for SWL between October 2018 and September 2019. Patient's demographics were collected. Using DUS, resistive index (RI), Δ RI, and ureteric jets were evaluated in both kidneys. Also, stone site, volume, density, skin to stone distance, degree of hydronephrosis, ureteral wall thickness (UWT) were evaluated by NCCT. Univariate and multivariate logistic regression analyses were performed to identify factors that contribute to treatment success. Correlation between ipsilateral RI with other radiological findings predicting stone impaction was done.
Results: A total of 93 patients were finally included (61 males and 32 females). The mean age was 31.4 ± 7.7 years. The success rate (absence of significant residuals post 1 month by NCCT) was 51.6%. In multivariate analysis, the presence of ureteric jet, ipsilateral lower RI, and ipsilateral lower UWT were independent factors for treatment success (P = 0.0001, 0.002, and 0.03, respectively). Also, ipsilateral absence of ureteric jet, increased hydronephrosis, and increased UWT were correlated with higher ipsilateral RI in prediction of stone impaction. Ipsilateral higher RI was found to achieve higher accuracy in stone impaction prediction (PPV of 94.8%).
Conclusion: Pretreatment DUS is a useful, non-invasive with a less irradiative tool for prediction of stone impaction and stone-free rate post-SWL for ureteric stones.
Minerva Urol Nefrol. 2020 Apr 16. doi: 10.23736/S0393-2249.20.03792-3. Online ahead of print. PMID: 32298068.
There is no clear definition of stone impaction as a measurable value. Also in the present paper the authors do not define but suspect impaction depending on a set of indirect values like hydronephrosis, thickening of the ureteric wall (UWT) and absent ureteric jets evaluated by Doppler ultrasound (DUS) and non-contrast CT(NCCT). I do not understand how they could state that the combination of the diverse factors raised the overall accuracy for stone impaction diagnosis to 96.9%.
The stone free rate was determined with NCCT 1 month after the last ESWL session. The single session stone free rate of 51,6 % (48 of 93) was low. 12 additional patients were stone free after additional ESWL sessions. 33 of 93 patients (35,4 %) finally required ureteroscopy for stone removal.
19 of these 33 patients needed ureteric stenting during ureteroscopy because of stone impaction.
Again difficult to understand why 14 had no impaction despite the high accuracy for stone impaction diagnosis of 96.9% documented.
ROC curves are a welcome by-product of statistical programs but I doubt that they frequently make their way into clinical practice.