Predictors of treatment failure and outcome assessment of extracorporeal shock wave lithotripsy with the Dornier Compact Delta® III Pro: Experience from the first 1000 treatments

Abstract

Background: The Dornier Compact Delta ® III Pro is a next-generation extracorporeal shock wave lithotripter featuring flat-panel detector technology for enhanced imaging and a compact modular design. This study evaluates treatment outcomes and predictors of failure for this system, representing the first published clinical experience. Methods: We retrospectively analyzed the first 1,000 consecutive patients treated with the Dornier Compact Delta®III Pro for renal or ureteric stones between May 2022 and November 2023 at a secondary hospital. Stone-free status was assessed via radiography, ultrasonography, or computed tomography (CT) within three months post-treatment. Predictive factors for treatment failure were identified through univariate and multivariate logistic regression analyses. Results: The cohort had a median age of 37 years (IQR: 32-44.2) and a body mass index (BMI) of 26 kg/m² (IQR: 24-29). Key characteristics included: prior urologic interventions in 36.6% of patients, single stones in 79.8% (median size 9 mm, IQR: 7-10), a median stone density of 1000 Hounsfield Units (HU) (IQR: 760-1200), and hydronephrosis observed in 55.3% of cases. Initial ESWL success was achieved in 80.5% of cases, increasing to 87.5% following repeat sessions (mean treatments: 1.2). Multivariate analysis identified four independent predictors of treatment failure: prior urologic intervention (adjusted odds ratio [aOR] 2.64, 95% CI 1.75-4.00, p < 0.001), multiple stones (aOR 0.45, 95% CI 0.24-0.77, p = 0.011), increased skin-to-stone distance (per cm: aOR 1.18, 95% CI 1.06-1.30, p < 0.001), and higher stone density (per 100 HU: aOR 1.12, 95% CI 1.06-1.18, p < 0.001). Conclusions: The Dornier Compact Delta®III Pro achieved an 87.3% stone-free rate with failure predictors consistent with established lithotripsy literature. These findings support the adoption of this device as an effective ESWL system, particularly for institutions prioritizing advanced imaging and a spaceefficient design.