Novel Biocompatible Adhesive for Intrarenal Embedding and Endoscopic Removal of Small Residual Fragments after Minimally Invasive Stone Treatment in an Ex Vivo Porcine Kidney Model: Initial Evaluation of a Prototype
Residual fragments related to endoscopic intracorporeal lithotripsy are a challenging problem. The impact of residual fragments remains a subject of discussion and growing evidence highlights that they have a central role in recurrent stone formation. Therefore, we developed a novel bioadhesive system for intrarenal embedding and retrieval of residual fragments after endoscopic lithotripsy in an ex vivo porcine kidney model.
Materials and Methods:
In a standardized setting 30 human stone fragments 1 mm or less were inserted in the lower pole of an ex vivo porcine kidney model. We assessed the extraction efficacy of flexible ureteroscopy using the bioadhesive system in 15 preparations and a conventional retrieval basket in 15. Outcomes were compared regarding the endoscopic and macroscopic stone-free rate, and overall time of retrieval.
Embedding and retrieving the residual fragment-bioadhesive complex were feasible in all trial runs. We observed no adverse effects such as adhesions between the adhesive and the renal collecting system or the instruments used. The stone-free rate was 100% and 60% in the bioadhesive and conventional retrieval groups, respectively (p = 0.017). Mean retrieval time was significantly shorter at 10 minutes 33 seconds vs 36 minutes 56 seconds in the bioadhesive group vs the conventional group (p = 0.001).
This novel method involving adhesive based complete removal of residual fragments from the collecting system has proved to be feasible. Our evaluation in a porcine kidney model revealed that this technology performed well. Further tests, including inpatient studies, are required to thoroughly evaluate the benefit and potential drawbacks of bioadhesive based extraction of residual fragments after intracorporeal lithotripsy.
- 1 : Randomized trial of stone fragment active retrieval versus spontaneous passage during holmium laser lithotripsy for ureteral stones. J Urol2010; 183: 1031. Link, Google Scholar
- 2 : Impact of pulse duration on Ho:YAG laser lithotripsy: fragmentation and dusting performance. World J Urol2014; 33: 471. Google Scholar
- 3 : Standardized flexible ureteroscopic technique to improve stone-free rates. Urology2012; 80: 1198. Google Scholar
- 4 : Clinical significance of residual fragments in 2015: impact, detection, and how to avoid them. World J Urol2016; 34: 771. Google Scholar
- 5 : How significant are clinically insignificant residual fragments following lithotripsy?. Curr Opin Urol2005; 15: 127. Google Scholar
- 6 : Natural history, complications and re-intervention rates of asymptomatic residual stone fragments after ureteroscopy: a report from the EDGE Research Consortium. J Urol2016; 195: 982. Link, Google Scholar
- 7 : Endoscopically determined stone clearance predicts disease recurrence within 5 years after retrograde intrarenal surgery. J Endourol2016; 30: 644. Google Scholar
- 8 Grunwald I, Richter K, Miernik A et al: Gel-forming system for removing urinary calculi and fragments thereof. Google Patents, CA 2910201 A1. Available at http://www.google.com.au/patents/CA2910201A1?cl=en. Publication date October 30, 2014. Google Scholar
- 9 Grunwald I, Richter K, Miernik A et al: Kit for producing a crosslinked gel for surrounding urinary calculi and/or fragments thereof. Google patents, CA 2910164 A1. Publication date October 30, 2014. Google Scholar
- 10 : Modern urinary stone therapy: is the era of extracorporeal shock wave lithotripsy at an end?. Urologe A2012; 51: 372. Google Scholar
- 11 : Diagnosis and initial management of kidney stones. Am Fam Physician2001; 63: 1329. Google Scholar
- 12 : 5-year-follow-up of patients with clinically insignificant residual fragments after extracorporeal shockwave lithotripsy. Eur Urol2005; 47: 860. Google Scholar
- 13 : Predictors of clinical significance of residual fragments after extracorporeal shockwave lithotripsy for renal stones. J Endourol2006; 20: 870. Google Scholar
- 14 : Post-ESWL, clinically insignificant residual stones: reality or myth?. Urology2002; 59: 20. Google Scholar
- 15 : Clinically insignificant residual fragments after percutaneous nephrolithotomy: medium-term follow-up. J Endourol2011; 25: 941. Google Scholar
- 16 : Natural history of residual fragments following percutaneous nephrostolithotomy. J Urol2009; 181: 1163. Link, Google Scholar
- 17 : Clinically insignificant residual fragments after flexible ureterorenoscopy: medium-term follow-up results. Urolithiasis2014; 42: 533. Google Scholar
- 18 : The natural history of renal stone fragments following ureteroscopy. Urology2011; 77: 564. Google Scholar
- 19 : Lower calyceal occlusion by autologous blood clot to prevent stone fragment reaccumulation after retrograde intra-renal surgery for lower calyceal stones: first experience of a new technique. J Endourol2008; 22: 2501. Google Scholar
- 20 : The glue-clot technique: a new technique description for small calyceal stone fragments removal. Urolithiasis2014; 42: 441. Google Scholar