Metal working – Method of mechanical manufacture – Obtaining plural product pieces from unitary workpiece
Reexamination Certificate
1998-12-08
2003-07-15
Vidovich, Gregory (Department: 3726)
Metal working
Method of mechanical manufacture
Obtaining plural product pieces from unitary workpiece
C029S527200, C264S171130, C264S171180, C604S523000
Reexamination Certificate
active
06591472
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods of fabricating medical vascular catheters adapted to be inserted into a blood vessel from an incision through the skin of a patient for introducing other devices or fluids for diagnostic or therapeutic purposes and particularly methods for fabricating such catheter bodies with catheter sections of differing flexibility.
BACKGROUND OF THE INVENTION
Catheters are tube-like medical instruments that are inserted into a body cavity, duct, tract, organ or blood vessel for a wide variety of diagnostic or therapeutic reasons, including delivery of diagnostic radiopaque materials, infusion of therapeutic drugs, performance of other interventional procedures, drainage of body cavities, organs or vessels, perfusion, and the like. Medical vascular catheters for each of these purposes can be introduced to numerous target sites within a patient's body by guiding the catheter through an incision made in the patient's skin and a blood vessel and then through the vascular system to the target site. Certain vascular catheters are introduced over a previously introduced guide wire or infusion wire and/or within a previously introduced guiding catheter or are advanced by blood flow in the vessel.
Medical vascular catheters generally comprise an elongated, flexible catheter tube or body with a catheter side wall enclosing a catheter lumen extending between a proximal catheter body end coupled to a relatively more rigid catheter hub to a distal catheter body end. The catheter body may be relatively straight or inherently curved or curved by insertion of a curved stiffening wire or guide wire through the catheter lumnen. The catheter body and catheter side wall are typically fabricated and dimensioned to minimize the catheter body outer diameter and side wall thickness and to maximize the catheter lumen diameter while retaining sufficient side wall flexibility and strength characteristics to enable the catheter to be used for the intended medical purpose.
Such medical catheters may be designed and used for diagnostic or therapeutic purposes in a wide range of catheter body sizes, lengths and configurations for accessing relatively large blood vessels, tracts, ducts or organs of the body or relatively small cardiac, neural or peripheral blood vessels that are frequently tortuous.
Guiding catheters are used to access a site in a patient's body and are formed to have a high degree of directional control and to provide a guiding catheter lumen through which smaller diameter, therapeutic catheters having little or no directional control are advanced to the site. In the field of vascular intervention, guiding catheters are particularly useful to guide angioplasty and atherectomy catheters through the vasculature to a site of a blockage, such as, coronary, cerebral and renal sites. Typically guiding catheters have a specific distal section shape adapted and sized to facilitate insertion to the site of interest.
The requirements of a good guiding catheter include high torque transmission and pushability for advancement through the vasculature, high catheter lumen lubricity to facilitate insertion of catheters and other devices therethrough, low kinking characteristics, and good distal shape memory. Additionally it is desirable to provide a smooth and relatively soft distal tip leading surface to prevent damage to the vascular vessels during advancement. It is also desirable to provide a radiopaque marker near the distal tip of the catheter to enhance its visibility by fluoroscopy. A wide variety of guiding catheters have been developed that address these design requirements as set forth for example in U.S. Pat. No. 4,817,613 to Jaraczewski et al. A number of distal soft tips and radiopaque markers are also described in the above-referenced, commonly assigned, '241 patent application and in commonly assigned U.S. Pat. Nos. 5,509,910 to Lunn and 5,545,149 to Brin et al. and in U.S. Pat. Nos. 4,283,447 to Flynn, 5,078,702 to Pomeranz, 5,234,416 to Macauley et al. and 5,221,270 to Parker.
Such guiding catheter bodies are typically formed with relatively long and stiff proximal sections or shafts and relatively short and soft distal tips, although short intermediate bonding segments or sections can be employed to assist bonding the soft distal tip to,the distal end of the proximal shaft as disclosed in the above-referenced '910 and '149 patents. Typically, the proximal section or shaft is formed of an inner tube, metal or polymeric filaments braided overlying the inner tube, and an outer tube over the braid, thereby providing a reinforced catheter shaft as disclosed in the above-referenced '910, '416, and '149 patents. The distal soft tip is either formed separately and adhered to the distal end of the catheter shaft through a variety of techniques or is formed integrally as an extension of one of the outer or inner liners as disclosed in the above-referenced '613 patent, for example. Butt welding techniques are disclosed in the above-referenced '910, '416, and '149 patents, and lap joint techniques are disclosed in U.S. Pat. Nos. 4,531,943 to Van Tassel et al. and 4,551,292, issued to Fletcher et al. and in the above-referenced '270 patent The exterior surface of the distal end of the catheter shaft is ground circumferentially using a “centerless” grinder to reduce the distal shaft wall thickness. The tip member is then fitted over the distal end of the catheter shaft to form a lap joint with the distal shaft and is then bonded to the distal shaft using an adhesive or other bonding technique.
Angiographic catheters of the type disclosed in U.S. Pat. No. 5,738,742 to Stevens are also formed with a wire braid reinforced proximal catheter section or shaft and a distal soft tip that is attached-thereto. In one approach characterized as prior art, a distal end portion of the proximal catheter shaft is centerless ground to a shape accommodating attachment of a separately formed soft distal tip that is then attached thereto. In a further approach presented by Stevens, a continuous reinforced tubing is first fabricated wherein an inner tube is formed over a mandrel, wire braid is applied over the inner tube outer wall during a continuous fabrication process, periodic sections of the wire braid are centerless ground away to expose the inner tube in those sections, and a continuous elastomeric coating is applied over the wire braid and exposed inner tube sections. The continuous reinforced tubing is cut to catheter body lengths including the sections without the wire braid, and the outer layer and inner layer of the section without wire braid are thermally fused together and shaped to form an integral soft distal tip. A very similar technique is disclosed in U.S. Pat. No. 4,321,226 to Markling for fabrication of catheters of unspecified types. Other angiographic catheters employ relatively stiff polymeric materials, e.g., certain nylon blends, polyamides, polyesters, etc., to provide a relatively rigid proximal catheter shaft and other softer blends of like materials in the distal end section or distal soft tip as disclosed, for example, in U.S. Pat. No. 4,563,181 to Wijayarathna et al.
Small diameter medical catheters or “microcatheters” having a catheter body outer diameter in the range of one, French (1F; 0.33 mm) to three French (3F; 1.00 mm), are typically used in tortuous vascular passageways for diagnostic and interventional neurological techniques, such as the imaging and treatment of aneurysms, tumors, arteriovenous malformations/fistulas, and the like, in the blood vessels in the brain. Such neurological catheters must be very flexible, particularly in distal sections thereof, to pass through the tortuous regions. Difficulties in endovascular positioning, however, make it desirable to impart high tensile and column strength over at least the proximal portion of the catheter. Additionally, the blood vessels of the brain are relatively fragile, so it is desirable that the catheter
Dunfee Albert H.
Noone Michael S.
Poole Matthew S.
Medtronic Inc.
Omgba Essama
Sterne, Kessler, Goldstein & Fox P.L.LC.
Vidovich Gregory
LandOfFree
Multiple segment catheter and method of fabrication does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multiple segment catheter and method of fabrication, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiple segment catheter and method of fabrication will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3025835