The aim of our study was to perform comparative investigation of the tissue safety of three different endoscopic lithotripter devices including a new single-probe/dual-energy lithotripter in an in vivo animal model. The Swiss LithoClast Trilogy was compared to the Storz Calcuson and the Swiss LithoClast Vario. The safety test simulated the accidental direct contact between lithotripter probes and the urothelium, which can occur when sliding off a stone or drilling through a calculus during lithotripsy. The safety test included a smallest (1.5 mm) and largest (3.3/3.4 mm) probe diameter per device.
Testing was performed in nine pigs (three animals per device). The bladder tissue was exposed to direct lithotripter probe contact at maximum power for 10 s to produce visible tissue lesions. Acute tissue trauma was evaluated using a simplified scoring model describing the expected bladder wall injuries for histological examination. After 7 days, all animals were killed, necropsied and examined post mortem. For between-group comparisons regarding microscopic histopathologic features, a Chi-square test was used. A p value < 0.05 was considered to be statistically significant.
Irrespective of the lithotripter used, no systemic signs of toxicity were observed. Histologically, signs of normal ongoing healing were observed on the bladder mucosa. There were no significant differences in histological findings taking changes of the epithelium (p = 0.360), the leucocyte infiltration (p = 0.123), the vascular congestion (p = 0.929) and the edema (p = 1.0) between the groups into account.
The results of this study demonstrated a comparable safety between all lithotripsy devices.
World journal of urology. 2019 May 29 [Epub ahead of print]
Wael Khoder, Frank Strittmatter, Abdulmajeed Alghamdi, Michael Seitz, Christian Stief, Markus Juergen Bader
Department of Urology, University Hospital Freiburg, Freiburg, Germany., Department of Urology, University Hospital of Munich Campus Großhadern, Munich, Germany., Department of Urology, University Hospital of Munich Campus Großhadern, Munich, Germany. .