Stents: Patent Titles
Anti-migration features and geometry for a shape memory polymer stent
Stents are often used in the gastrointestinal tract to treat malignant or benign strictures as palliative or supporting treatment to chemotherapy or surgery. With biliary stent applications, plastic stents are often used. Plastic stents are typically have an outer diameter of 3.5 mm and an inner diameter of 2.5 mm and need to be exchanged relatively often (e.g., every three months) due to occlusion from bile. However, an advantage of plastic stents, besides their lower cost, is that their relative small size enables their use within and endoscopy instrument or endoscope. Conversely, self expanding metal stents (SEMS), are also useable and tend to have a longer patency than plastic stents because of their larger diameters, typically 8-10 mm, and having a further advantage that metal stents are collapsible from a larger to smaller diameter and may fit within and endoscope, and then expanded to a larger diameter. However, plastic stents are removable, whereas, metal stents generally are not. Common practice calls for removing stents when treatment of benign strictures is completed.
Because of inherent material deficiencies, plastic stents cannot be made and reliably used, having larger diameters that collapse down to small diameters and retaining good compression resistance as with self expanding metal stents.
Jordan and Sahatjian of Boston Scientific Scimed developed a radially-expandable stent for implantation in a bodily passageway, being expandable from an initial unexpanded state to an expanded state, having an outer surface with a geometric pattern covering said outer surface to minimize migration after implantation is provided. This stent can be manufactured by injection molding. The surface geometry of the stent is controlled by cutting the inverse geometric configuration into the inner diameter of the mold. The inner surface of the mold can contain any of various geometrical patterns such as a helical coil, mesh, rings or rough textured surface, as shown in the accompanying figures. Any change in geometry on the exterior wall of the implant may minimize migration while preferably preventing tissue damage in situ or upon removal. Additionally one type allows fluids from either the pancreatic duct or cystic duct to pass between the wall of the bile duct and the outer surface of the stent, should the stent pass over these ducts.
Polymer tube expansion apparatus to maximize fracture toughness
Kleiner et al of Abbott Cardiovascular Systems Inc. fabricated a polymeric stent with improved fracture toughness by expanding a polymer tube along its entire length at the same time and fabricating a stent from the expanded tube. (RDC 11/16/2012)
Method of making a hybrid stent
Prabhu of Abbott Cardiovascular Systems Inc., formed a stent by encasing or encapsulating metallic rings in an inner polymeric layer and an outer polymeric layer. At least one polymer link connects adjacent metallic rings. The stent is drug loaded with one or more therapeutic agent or drug, for example, to reduce the likelihood of the development of restenosis in the coronary arteries. The inner and outer polymeric materials can be of the same polymer or different polymer to achieve different results, such as enhancing flexibility and providing a stent that is visible under MRI, computer tomography and x-ray fluoroscopy. (RDC 9/5/2012)
Biodisintegrable medical devices
Sheth of Boston Scientific Scimed, Inc., Minnesota, developed partially biodisintegrable ureteral stents, urethral stents, coronary vascular stents, peripheral vascular stents, cerebral stents, biliary stents, tracheal stents, gastrointestinal stents, and esophageal stents. (RDC 8/20/2012)
Method of forming a stent pattern on a tube
Abbbate et al of Advanced Cardiovascular Systems, Inc., California, fabricated an implantable medical device from a tube or a sheet in an expanded or stretched state. The implantable medical device may be an endoprosthesis such as a stent. This may include radially expanding a tube about a cylindrical axis of the tube from a first diameter to a second diameter. The method may further include forming a pattern on at least a portion of the expanded tube. Additional embodiments may include forming a stent pattern on a stretched sheet from which a stent may be formed. In addition, a stent pattern may be formed on a tube that is formed from a stretched sheet. (RDC 8/17/2012)
Methods of manufacturing linearly expandable ureteral stents
Gellman of Boston Scientific Scimed, Inc., Minnesota, developed a painless ureteral stent with a sidewall having a spiral-shaped opening so that the elongated member moves between a retracted configuration and an expanded configuration along a longitudinal axis of the lumen. (RDC 8/16/2012)
Stent retention mold and method
Kent et al of Advanced Cardiovascular Systems, Inc., California, developed a stent retention mold including two half-molds, each half-mold including a stent supporting surface, and protrusions on the stent supporting surfaces. A portion of the balloon extends through a gap of the stent into a space between two protrusions. (RDC 8/14/2012)
Method of fabricating an implantable medical device with biaxially oriented polymers
Huang, Schalble and Gale of Advanced Cardiovascular Systems, California, developed an implantable medical device, such as a stent, from a tube with desirable mechanical properties, such as improved circumferential strength and rigidity. Improved circumferential strength and rigidity may be obtained by inducing molecular orientation in materials for use in manufacturing an implantable medical device. Molecular orientation is promoted by expansion of a molten annular polymer film or by inducing circumferential molecular orientation by inducing circumferential flow in a molten polymer or by expansion of a polymer tube. (RDC 6/19/2012)
Methods for fabricating polymer-bioceramic composite implantable medical devices
Huang and Gale of Abbott Cardiovascular Systems Inc., fabricated a stent using a suspension solution by combining a first fluid containing a dissolved polymer and suspended bioceramic particles with a second fluid to form a fluid mixture, wherein the second fluid is a poor solvent for the polymer and is immiscible with the first fluid so that the fluid mixture comprises a second fluid phase and suspension solution phase; spraying the fluid mixture to form a plurality of droplets; allowing at least some of the polymer to separate from the fluid in the droplets, wherein at least some of the bioceramic particles separate with the polymer to form a composite mixture, the composite mixture comprising the removed bioceramic particles dispersed within the removed polymer. A stent is fabricated from the composite mixture. (RDC 6/18/2012)
Methods for making an encapsulated stent
McCrea, Edwin and Banas of Bard Peripheral Vascular, Arizona, formed an encapsulated stent with a first seamless unsintered ePTFE tube and a second seamless sintered ePTFE tube surrounding a self-expanding stent between the first and second ePTFE tubes to form an assembly. The ePTFE tubes are joined through openings in a wall of the stent by pressure and heat. (RDC 5/14/2012)
Optimizing fracture toughness of polymeric stent
Gayle et al of Abbott Cardiovascular Systems, Cailifornia fabraicated a stent assembly by radially expanding polymer tube and crimping the stent onto a catheter assembly at the desired crimping temperature leading to its optimal fracture toughness. (RDC 2/21/21012)
Stuctural Hydrogel Polymer Device
Epstein, Massachusetts, developed a process for forming completely hydrogel polymer device that maintains lumen patency which allows for numerous applications such as catheters and stents. These structures conduct and allow fluids to pass from one end to the other without physiological rejection, inflammation, or other complications. The process is based on casting hydrogel solutions on a mandrel to form multilayer structures such as catheters and stents. (RDC 1/26/2012)
Roger D. Corneliussen
Maro Polymer Links
Tel: 610 363 9920
Fax: 610 363 9921
Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
** Date of latest addition; date of first entry is 1/26/2012.