Impact of advanced lithotripter technology on SWL success: ınsights from Modulith SLK ınline outcomes

This study aims to evaluate the success rate of Shock Wave Lithotripsy (SWL) in treating kidney stones using the Modulith SLK Inline lithotripter, with a focus on the importance of device efficacy as emphasized in EAU guidelines.

This retrospective single-center study was conducted between June 2023 and June 2024. Inclusion criteria were adult patients (> 18 years) with radiologically confirmed renal stones smaller than 15 mm in diameter. Exclusion criteria included patients with solitary kidneys, significant renal functional deterioration, skeletal deformities, active urinary tract infections, pregnancy, or coagulopathies. Treatment outcomes were collected and analyzed in detail, considering patients' demographic characteristics (age, gender) and stone parameters (size, location, and hardness [Hounsfield Unit, HU]). The SWL procedures were performed using the Modulith SLK Inline lithotripter (Storz Medical, Switzerland). The success of SWL was defined as achieving complete stone clearance or the presence of clinically insignificant residual fragments (CIRF) (< 4 mm). This study seeks to provide detailed insights into the optimal use cases of SWL as a non-invasive yet effective treatment option for smaller, more manageable stones.

The mean age of the 208 patients included in the study was 42.2 ± 12.7 years (18-75), with a male-to-female ratio of 1.9:1. The mean stone size across all patients was 10.3 mm, and the average HU value was 874.0 ± 283.2. Patients who achieved a completely stone-free status had significantly lower HU values (p = 0.049). The overall success rate of SWL was 78.8%, with 164 patients achieving complete stone clearance. When cases with clinically insignificant residual fragments (CIRF, < 4 mm) were included as successful outcomes, the overall success rate increased to 92.3%. This distinction highlights the inclusion of patients with small residual fragments that are deemed clinically irrelevant in the adjusted success rate. In cases with successful outcomes, the mean stone size was 10.3 mm, whereas it was 12.5 mm in patients with residual fragments or treatment failure. A statistically significant relationship was identified between stone size and treatment success rates (p < 0.001). In contrast, stone localization did not have a significant impact on SWL success rates (p = 0.377).

SWL has demonstrated its effectiveness in kidney stone treatment with a 78.8% complete stone-free rate using the Modulith SLK Inline lithotripter. Higher success rates were achieved with smaller stones (< 15 mm) and lower HU values. These findings support the significance of advanced lithotripter technology in establishing SWL as a valuable non-invasive option for stones under 15 mm.