Viability and biocompatibility of an adhesive system for intrarenal embedding and endoscopic removal of small residual fragments in minimally-invasive stone treatment in an in vivo pig model.

Abstract

To evaluate the viability and biocompatibility of a novel, patented bioadhesive system for intrarenal embedding and retrieval of residual fragments after endoscopic lithotripsy. Complete stone clearance via active removal of residual fragments (RF) after intracorporeal laser lithotripsy may be time-consuming and fail in many cases. Therefore, the novel adhesive has been developed and evaluated for the first time in an in vivo pig model in the present work. Four female domestic pigs underwent flexible ureteroscopy (RIRS) or percutaneous nephrolithotomy (PNL) under general anesthesia (8 kidneys, 4×RIRS, 4×PNL) evaluating the bioadhesive system. RIRS without adhesive system (sham procedure, kidney I); 3×RIRS using the bioadhesive system (kidneys II-IV); and 4×PNL using the bioadhesive system (V-VIII). We endoscopically inserted standardized human stone probes followed by comminution using Ho:YAG lithotripsy. The bioadhesive (kidney II-VIII) was then applied and the adhesive-stone fragment complex extracted. After nephrectomy, all kidneys were evaluated by two independent, blinded pathologists. Endpoints were the procedure's safety and adhesive system's biocompatibility. We observed no substantial toxic effects. We were able to embed and remove 80-90% of fragments. However, because of the pig's hampering pyelocaliceal anatomy, a quantified, proportional assessment of the embedded fragments was compromised. For the first time, we demonstrated the proven feasibility and safety of this novel bioadhesive system for embedding and endoscopically removing small RF in conjunction with a lack of organ toxicity in vivo.