The primary objective of urolithiasis therapy is complete stone removal and highest stone-clearance rates possible to minimize recurrence. A novel approach that employs a magnetic suspension and a magnetic probe for the passive collection and removal of small residual fragments was developed. This study assessed the feasibility of this system in porcine models. Five female domestic pigs underwent retrograde intrarenal surgery under general anaesthesia to assess the new magnetic system. Pre-analysed human calculi were endoscopically inserted and comminuted using lithotripsy. The magnetic suspension was applied, and the magnetic-stone fragment complex was extracted. After nephrectomy, independent blinded pathologists evaluated all the kidneys. Safety and tolerance assessments revealed no adverse events (i.e. no complications on the Clavien-Dindo scale > 1) or complications associated with treatment. This study revealed superficial urothelial damage in all animals, characterized by desquamation and inflammation, caused primarily by the insertion of access sheaths and laser lithotripsy. Residual magnetic particles were observed in the renal pelvis but did not show signs of toxicity even though this study is limited to the acute treatment. No pathological indicators were observed in the hemogram and urinalysis. Overall, the treatment did not cause any significant pathological changes. Preclinical in vivo evaluation of magnetic extraction of small rest fragments in porcine kidneys presents a promising, atraumatic approach for fragments removal. It demonstrated safety, tolerance, and feasibility that warrants clinical investigation. This method has the potential to increase stone-clearance rates with shorter extraction times, offering a possibility for addressing the challenge of urolithiasis in clinical practice.
Urolithiasis. 2024 Dec 24*** epublish ***
Thomas Amiel, Shyam Srinivasan, Chiara Turrina, Florian Ebel, Michael Straub, Sebastian P Schwaminger
Department of Urology, University Hospital Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. ., Chair of Bioseparation Engineering, School of Engineering and Design, Technical University of Munich (TUM), Boltzmannstr. 15, 85748, Garching, Germany., Department of Urology, University Hospital Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany., Division of Medicinal Chemistry, Otto Loewi Research Center, Medical University of Graz, Neue Stiftingtalstr. 6, 8010, Graz, Austria. .