nitinol and Gallstones

Although numerous retrieval baskets are currently available for the extraction of bile duct stones, their mechanical properties have not been evaluated. This study aimed to ascertain the characteristics of retrieval baskets for bile duct stones by examining their mechanical properties.. This experimental study tested the mechanical properties of seven retrieval baskets for bile duct stones. The radial force (RF) was measured using a dedicated measurement device and the axial force (AF) was measured using the conventional manual method.. The mean RF differed significantly among the baskets (p < 0.001) and was the strongest for VorticCatch (1.62 N ± 0.02) and COAXIS (1.62 N ± 0.04), followed by RASEN (1.27 N ± 0.02), Memory Basket (0.95 N ± 0.01), 8-wire Nitinol Basket (0.93 N ± 0.01), StoneHunter (0.78 N ± 0.01) and Flower Basket (0.37 N ± 0.01), respectively. The mean AF differed significantly among the baskets (p < 0.001) and was the highest for VorticCatch (0.668 N ± 0.032), followed by COAXIS (0.629 N ± 0.041), StoneHunter (0.574 N ± 0.037), 8-wire Nitinol Basket (0.546 N ± 0.010), Memory Basket (0.542 N ± 0.024), RASEN (0.435 N ± 0.008) and Flower Basket (0.297 N ± 0.011), respectively. The baskets were categorized into four groups with comparable mechanical properties based on the RF and AF: group 1, low RF and low AF; group 2, moderate RF and moderate AF; group 3, high RF and moderate AF; and group 4, high RF and high AF.. This study revealed distinct mechanical properties of various retrieval baskets used for extracting bile duct stones, which may enhance the understanding of their action. Our results could also aid the development of retrieval baskets in future.

Topics: Alloys; Catheters; Cholangiopancreatography, Endoscopic Retrograde; Gallstones; Humans

BACKGROUND : Endoscopic stone extraction is often challenging in patients with a significant lower bile duct corner pocket, where small stones are likely to escape and become impacted. This study aimed to determine the utility of different types of baskets for retrieving corner pocket stones. METHODS : Seven types of retrieval baskets were evaluated on silicone models. The study outcomes included the characteristics of each basket and technical success rates associated with the retrieval of stones impacted in the corner pocket. RESULTS : The overall success rate was only 27.5 %, with significant differences between the baskets (

Topics: Alloys; Bile Ducts; Calculi; Catheters; Cholangiopancreatography, Endoscopic Retrograde; Gallstones; Humans; Silicones

The treatment of difficult common bile duct stones (CBDS) remains a big challenge around the world. Biliary stenting is a widely accepted rescue method in patients with failed stone extraction under endoscopic retrograde cholangiopancreatography. Fully covered self-expanding metal stent (FCSEMS) has gained increasing attention in the management of difficult CBDS.. To manufacture a drug-eluting FCSEMS, which can achieve controlled release of stone-dissolving agents and speed up the dissolution of CBDS.. Customized covered nitinol stents were adopted. Sodium cholate (SC) and disodium ethylene diamine tetraacetic acid (EDTA disodium, EDTA for short) were used as stone-dissolving agents. Three different types of drug-eluting stents were manufactured by dip coating (Stent I), coaxial electrospinning (Stent II), and dip coating combined with electrospinning (Stent III), respectively. The drug-release behavior and stone-dissolving efficacy of these stents were evaluated. Stent I and Stent II had obvious burst release of drugs in the first 5 d while Stent III presented controlled and sustainable drug release for 30 d. In still buffer, the final stone mass-loss rate of each group was 5.19% ± 0.69% for naked FCSEMS, 20.37% ± 2.13% for Stent I, 24.57% ± 1.45% for Stent II, and 33.72% ± 0.67% for Stent III. In flowing bile, the final stone mass-loss rate of each group was 5.87% ± 0.25% for naked FCSEMS, 6.36% ± 0.48% for Stent I, 6.38% ± 0.37% for Stent II, and 8.15% ± 0.27% for Stent III. Stent III caused the most stone mass-loss no matter in still buffer or in flowing bile, which was significantly higher than those of other groups (. The novel SC and EDTA-eluting FCSEMS is efficient in diminishing CBDS

Topics: Alloys; Animals; Common Bile Duct; Disease Models, Animal; Drug Carriers; Drug Liberation; Drug-Eluting Stents; Edetic Acid; Gallstones; Humans; Male; Nanofibers; Polyesters; Self Expandable Metallic Stents; Sodium Cholate; Swine; Swine, Miniature; Treatment Outcome

This paper presents the development of an improved stone retrieval device that uses a newly designed cage of Nitinol wires encompassing a mesh basket made of a material that is laser resistant. Current methods to extract large stones involve imaging, using a laser to fragment the stones and then using existing cage-like baskets to trap the fragments individually and extracting them one at a time. These procedures are tedious, and may result in leaving some fragments behind that can reform causing the need for another procedure. The device presented in this paper will have a mesh-like sack which will consist of a laser resistant material of polytetrafluoroethylene (PTFE) enclosed within a newly designed Nitinol cage. Two alternate designs are provided for the cage in this paper. The handle of the device is revised to allow for a 3 Fr (1 mm) opening such that a laser's fiber optic cable can enter the device. Using this device a laser can be used to fragment the stone, and all the fragments are retained in the basket in both the design options. The basket can then be retracted allowing for the retrieval of all the fragments in one shot. The stone retrieval basket presented in this paper will significantly improve the efficiency and effectiveness of lithotripsy procedures for removal of large kidney and biliary tract stones.

Topics: Alloys; Equipment Design; Equipment Failure Analysis; Gallstones; Humans; Kidney Calculi; Lithotripsy, Laser; Polytetrafluoroethylene