Gadelmoula M. et al.,2019: Percutaneous nephrolithotomy versus shock wave lithotripsy for high-density moderate-sized renal stones: A prospective randomized study
Gadelmoula M, Elderwy AA, Abdelkawi IF, Moeen AM, Althamthami G, Abdel-Moneim AM.
Department of Urology, Urology and Nephrology Hospital, Assiut University, Assiut, Egypt.
The management of renal stones of high density (>1000 Hounsfield units) on non-contrast computed tomography (NCCT), and moderate sized (15-25 mm) is still debatable.
The aim of this study was to compare the outcomes of percutaneous nephrolithotomy (PCNL) and shock wave lithotripsy (SWL) for the high-density and moderate-sized renal stones regarding the stone-free rate (SFR), morbidity, and patients' quality of life.
Settings and Design:
This is a prospective randomized study.
Patients and Methods:
Eighty consecutive patients with renal stones, excluding those with lower calyceal stones, were randomized to receive either PCNL or SWL (40 in each arm). Patients were followed up by abdominal ultrasound and plain X-ray (NCCT if indicated) till clearance of stone. Outcomes, complications, costs, and SF-8 Health Survey scoring were recorded for each group.
We used Stata software, version 9.2 (Intercooled STATA®; StataCorp LP College Station, Texas, USA). Comparison of the two groups was made with regard to patient and stone criteria and the procedure details. Continuous variables were compared using the Mann-Whitney U-test with values shown as the median and interquartile range. Categorical variables were compared using the Pearson's Chi-square/Fisher's exact test. Multivariate logistic regression analysis was used to identify variables independently associated with the stone clearance after two sessions of SWL. P < 0.05 was considered statistically significant.
The basic characteristics of both groups were comparable. After a single treatment session, the SFR was 80% and 27.5% for PCNL and SWL, respectively (P < 0.001). The overall 3-month SFR was 87.5% versus 90%, respectively (P = 0.723). The median number of the required maneuvers was 1 (range: 1-3) for PCNL versus 2 (range: 1-4) for SWL (P < 0.001). The complication rate was 10% and 7.5%, respectively (P = 0.692). The cost of SWL was significantly lower (P < 0.001). On multivariate analysis, a single stone was an independent predictor for stone clearance after two sessions of SWL (odds ratio: 7.26, 95% confidence interval: 1.13-46.62, P = 0.037).
PCNL for the dense, and moderate-sized renal stone provides higher initial success and lower re-treatment rates compared with SWL with comparable outcome after 3 months of therapy. However, SWL is an alternative, especially for a single stone.
Urol Ann. 2019 Oct-Dec;11(4):426-431. doi: 10.4103/UA.UA_63_19. FREE ARTICLE
As a prospective randomized comparison between PCNL and SWL this is an interesting study. Although the success after one SWL session was significantly lower than usually expected, the explanation most certainly is the selection of hard stones. With an average HU of around 1250 it can be assumed that most stones were composed of COM. Interestingly, with generous mono-therapy re-treatment, the final outcome in terms of SFR was 87.5% for PCNL and 90.0 % for SWL. Auxiliary procedures with alternative treatment modalities were not accounted for.
It is of note that the authors found SWL less expensive than PCNL a conclusion that most certainly is based on the different requirements of anesthesia. Approximate estimates of STI, stone treatment index  showed values at approximately the same levels: 3.8 for SWL and 5.10 for PCNL.
Tiselius HG, Ringdén I.
Stone treatment index: a mathematical summary of the procedure for removal of stones from the urinary tract.
J Endourol. 2007; 11:1261-1269