Shim M et al, 2017: The efficacy of performing shockwave lithotripsy before retrograde intrarenal surgery in the treatment of multiple or large (≥1.5 cm) nephrolithiasis: A propensity score matched analysis.
Shim M, Park M, Park HK.
Department of Urology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea.
Department of Urology, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea.
PURPOSE: To investigate the effect of performing shockwave lithotripsy (SWL) before retrograde intrarenal surgery (RIRS) on the treatment outcomes of patients with nephrolithiasis.
MATERIALS AND METHODS: The data of 189 patients with renal stones who underwent RIRS from July 2007 to July 2014 was reviewed retrospectively. Patients with stones larger than 1.5 cm were recommended to undergo SWL before RIRS. Patients were divided into 2 groups based on whether the preoperative SWL was performed (group 1, n=68) or not (group 2, n=121). The cohorts of the 2 groups cohorts were matched 1:1 using propensity score analysis. Patient, stone characteristics, operative parameters, and stone-free rates were compared.
RESULTS: Patients in groups 1 and 2 were matched with respect to stone size, number, and location, leaving 57 patients in each group. After matching, no differences were identified between the 2 groups regarding age, body mass index, sex, stone composition, density and multiplicity. Compared to group 2 patients, patients in group 1 had fewer number of procedures performed (1.10 vs. 1.26, p=0.045) and higher stone-free rate (89.4% vs.73.6%, p=0.039). In multivariate analysis, Non lower calyceal location (odd ratio [OR], 8.215; 95% confidence interval [CI], 1.782-21.982; p=0.041), stone size (OR, 6.932; 95% CI, 1.022-18.283; p<0.001), and preoperative SWL (OR, 2.210; 95% CI, 1.058-7.157; p=0.019) were independent factors predicting a stone-free state after RIRS.
CONCLUSIONS: Performing SWL before RIRS may favor stone eliminations during surgery and increase the stone-free rate in selected patients.
Investig Clin Urol. 2017 Jan;58(1):27-33. doi: 10.4111/icu.2017.58.1.27. FREE ARTICLE
Despite the increasing enthusiasm for endoscopic stone removal, particularly RIRS, it is obvious that such methods are not without problems. The long duration of the surgical procedure, need of repeated procedures and nevertheless variable success rates were the reasons for applying a combined approach with SWL + RIRS.
In this retrospective study on matched patients with large (> 1.5 cm) stones the stone-free rate was higher in patients treated with SWL than in patients who had been treated with RIRS without SWL.
Unfortunately the authors used the largest stone diameter(s) to assess the stone burden rather than a more representative measure. In the series of images in the publication one can wonder if a repeated non-invasive procedure (SWL) also had been successful. Obviously in several cases in both groups SWL was carried out after RIRS.
Nevertheless, the pre-RIRS disintegration with SWL is an interesting concept that needs to be further explored.