Confinement of kidney-stone fragments during lithotripsy

a technology of kidney stones and lithotripsy, which is applied in the field of lithotripsy and kidney stones, can solve the problems of fragments that are still too large to be easily passed, fragments that might become undetectable, and urolithiasis is also a significant health problem

Inactive Publication Date: 2005-06-30
GENZYME CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Urolithiasis is also a significant health problem in the United States.
However there are several complications which can result from standard ESWL.
A major problem with the procedure is that when kidney stones are fragmented the energy is sufficient to widely distribute them throughout the ureter and kidney.
Further, fragments might become undetectable (e.g., too small to be imaged by fluoroscopy) but still too big to be easily passed.
The laser produces a vaporization bubble at the tip of the fiber optic and the energy is transferred to the stone and leads to fragmentation.
However, proximal ureteral stone migration during laser lithotripsy accounts for a high percentage of ureteroscopic failures.

Method used

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  • Confinement of kidney-stone fragments during lithotripsy
  • Confinement of kidney-stone fragments during lithotripsy
  • Confinement of kidney-stone fragments during lithotripsy

Examples

Experimental program
Comparison scheme
Effect test

example 1

Gelation Temperature of Selected Pluronic® and Tetronic® Polymer Solutions

[0106] The polymer was weighed into a plastic tube. To achieve the required concentration the weight was multiplied by 4, for 25 weight percent (w %), and by 5, for 20 weight percent (w %), and the required final weight was achieved by adding saline. The solutions were placed in the fridge at 4° C. and usually were ready the next morning. Gelation points were measures in a Brookfield viscometer and the point at which viscosity exceeded the range of the plate / cone (>102,000 cP) was called the gelation temperature.

TABLE 1Gelation Temperature of Selected Inverse Thermosensitive PolymerSolutions in SalinepolymerconcentrationtemperatureTetronic 110725 w %  27° C.Tetronic 110720 w %  34° C.Purified Tetronic 110725 w %  22° C.Purified Tetronic 110720 w %32.5° C.Tetronic 130725 w %24.5° C.Tetronic 130720 w %  31° C.Purified Tetronic 130725 w %  20° C.Purified Tetronic 130720 w %  26° C.Pluronic F10825 w %  26° C.Pl...

example 2

Gelation Temperature of Selected Pluronic® and Tetronic® Polymer Solutions with Iodinated Contrast Agent

[0107] Purified polymers were weighed into 50 mL centrifuge tubes and a 1:1 mixture of saline and 100% Omnipaque 300 were added until a specific weight percentage was reached. Gelation points were measured in a Brookfield viscometer and the point at which the viscosity exceeded the range of the plate / cone (>102,000 cP) was called the gelation point. All solutions were further heated to 37° C. to ascertain that the material still exceeded the viscosity range and remained a gel. All gels passed.

TABLE 2Gelation Temperature of Purified Inverse Thermosensitive PolymerSolutions containing 50 w % Omnipaque 300polymerconcentrationtemperaturePurified Tetronic 110720 w %  24° C.Purified Tetronic 130721 w %26.5° C.Purified Pluronic F10818 w %21.5° C.Purified Pluronic F12718 w %  18° C.

example 3

Plastic Tube Experiments

[0108] A plastic tube with an inner diameter of 0.9 cm was used as a mimic of a ureter. The tube was partially filled with saline and the kidney stone placed into the middle of the tube. A ureteroscope was placed inside the tube close to the stone and cold polymer solutions were injected behind the stone. The stone was fragmented using either electro-hydraulic lithotripsy or laser lithotripsy. Various inverse thermosensitive polymer solutions such as purified Pluronic F108 (poloxamer 338), Pluronic F127 (poloxamer 407) and Tetronic 1307, were tested in this set-up in concentrations ranging from 15 to 25 w %. In all cases, the stone could be fragmented into smaller particles and the gel captures all fragments. The lower polymer concentrations (15 w %) resulted in rather soft gels, while the higher polymer concentrations (25 w %) were difficult to deploy due to the increased viscosity of the polymer solution and early onset of gelation.

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Abstract

The present invention improves significantly the success rate of lithotripsy and reduces the risk of tissue damage, by injecting temporary plugs in front and behind a concretion (for extracorporeal lithotripsy) or behind a concretion (for intracorporeal lithotripsy). One aspect of the present invention relates to injecting an inverse thermosensitive polymer solution into a lumen, thereby preventing the migration of a concretion, or its fragments, upon extracorporeal or intracorporeal lithotripsy.

Description

RELATED APPLICATIONS [0001] This application claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60 / 510,505, filed Oct. 14, 2003; the specification of which is hereby incorporated in its entirety by reference.BACKGROUND [0002] The prevalence of urolithiasis, or kidney stone disease, is increasing with an aging population. A recent German epidemiology study showed an increase in the prevalence of kidney stones in the general German population from about 0.5% in 1971 to about 1.5% in 2000. (Hesse A. et al. European Urology 2003, 44, 709-713). Urolithiasis is also a significant health problem in the United States. It is estimated that between 5-10% of the general population will develop a urinary concretion during their lifetime. (Pak, C. T. Diseases of the Kidney, 5th Edition; Boston; Little, Brown & Co.; 1993; pp. 729-743). The peak onset of urolithiasis is typically between 20 and 30 years of age, and males are effected more often then females. [0003] Sinc...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61BA61B17/22A61F2/01A61H1/00
CPCA61B17/12022A61B17/225A61B17/12045A61B17/12099A61B17/12186A61B17/22012A61B17/2202A61B17/22022A61B2017/12127A61B2017/22021A61B2017/22025A61B2017/22054A61B2017/22067A61B2017/22082A61F2/013A61B17/1204A61P41/00A61B18/26A61H23/008
Inventor SCHWARZ, ALEXANDERMCDOUGAL, W. SCOTT
Owner GENZYME CORP
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