Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1997-10-02
2001-04-17
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S527000
Reexamination Certificate
active
06217566
ABSTRACT:
FIELD OF THE INVENTION
This invention is a surgical device. In particular, it is a delivery catheter assembly used typically, but not exclusively, in the peripheral vasculature of the human body. The catheter is configured in such a way that the lumen is exceptionally large and the catheter wall is exceptionally thin for a catheter of this class. The distal portion of the catheter contains a kink-resisting member, preferably a super-elastic alloy ribbon braid, which is embedded in the catheter wall. Proximally of the kink-resisting member, the catheter typically will have no other kink-resisting members. Finally, the catheter assembly uses long conical joints between component tubular members to provide smooth and strong transitions between those members.
BACKGROUND OF THE INVENTION
Catheters are increasingly used to access remote regions of the human body, and in doing so, delivering diagnostic or therapeutic agents to those sites. In particular, catheters which use the circulatory system as the pathway to these treatment sites have become especially practical over the past ten years.
Often the site which one desires to access by catheter is within a soft tissue such as the liver. Although the liver itself is relatively easy to reach, it is not straightforward to progress deep into the liver. A catheter must be passed through ever-narrower regions of the arterial system until the catheter reaches a selected site. It is apparent that to reach sites deep within an organ such as the liver, the outside diameter of a catheter should be small. However, it is often the case that merely reducing the outside diameter of a catheter will significantly increase a catheter's propensity for kinking and does not improve its ability to follow guidewires of sophisticated design, into distant reaches of the vasculature. To provide sufficient pushability, kink-resistance, and fluid flow capabilities is not a trivial task. As to the latter requirement, it should be apparent that delivery of fluid through a small lumen catheter can be difficult and even dangerous if the lumen is too small. High pressures produced even by the smallest of syringes can rupture a small lumen catheter or even detach a distal tip if the wall of the catheter is too weak to withstand such flowing pressures.
The delivery catheter of this invention uses two features, among others, to provide a delivery catheter having a very large lumen for the class of catheters described, high kink-resistance, and a substantial burst resistance.
The kink-resisting member is preferably a woven braid produced from a number of super-elastic alloy ribbons. The kink-resisting alloy is embedded in a thermoplastic layer. The catheter is preferably built without butt joints in the assembly because of the inability of these joints to withstand high pressure. The catheter in this invention utilizes very shallow conical joints to provide a significant surface area between adjoining tubular members so to provide both superior strength and smooth transitions in flexibility and material from one section to another. We have found that by optimization of these joints, the wall of the catheter may be made significantly thinner than in other devices of the same class and consequently the lumen may be made significantly larger as well. For instance, a typical catheter made using the two tenets of the invention described above may be made in a 2.7 French size and yet have a larger lumen in commercial 3 French catheters made using conventional techniques.
Devices such as these are used to provide fluid materials such as dyes and treatment materials to sites in the body. These fluids are often viscous and difficult to inject. Furthermore, these catheters are used to occlude blood flow to portions of the treated organ. Since it is desirable to treat the smallest possible effective region of the organ, small diameter catheters with larger diameter lumen are highly desirable.
There are other ways of causing a catheter to proceed through the human vasculature to a selected site, but a guidewire-aided catheter is considered to be both quite quick and somewhat more accurate than the other procedures. One such alternative procedure is the use of a flow-directed catheter. These devices often have a small balloon situated on the distal end of the catheter which may be alternately deflated and inflated as the need to select a route for the catheter is encountered.
This invention is an adaptable one and may be used in a variety of catheter formats. The invention utilizes the concept of combining one or more polymeric tubes with a metallic braid comprising ribbons of a super-elastic alloy. The construction technique has the benefit of producing catheter sections having small overall diameters but with exceptional strength, resistance to kinking, and recovery from kinking (even in vivo) should such kinking occur.
The use of braids in a catheter body is not a novel concept. Typical background patents are discussed below. However, none of these documents have used our concept to produce a catheter which has the physical capabilities of the catheter of this invention.
Multi-Wrap Catheters
There are a number of catheters discussed in the literature which utilize catheter bodies having multiply-wrapped reinforcing material. These catheters include structures having braided bands or ones in which the spirally wound material is simply wound in one direction and the following layer or layers are wound in the other.
Krippendorf, U.S. Pat. No. 2,437,542, describes a “catheter-type instrument” which is typically used as a ureteral or urethral catheter. The physical design is said to be one having a distal section of greater flexibility and a proximal section of lesser flexibility. The device is made of intertwined threads of silk, cotton, or some synthetic fiber. It is made by impregnating a fabric-based tube with a stiffening medium which renders the tube stiff yet flexible. The thus-plasticized tubing is then dipped in some other medium to allow the formation of a flexible varnish-like layer. This latter material may be a tung oil base or a phenolic resin and a suitable plasticizer. There is no indication that this device is of the flexibility described herein. Additionally, it appears to be the type which is used in some region other than in the body's periphery or in its soft tissues.
Similarly, U.S. Pat. No. 3,416,531, to Edwards, shows a catheter having braiding-edge walls. The device further has additional layers of other polymers such as TEFLON and the like. The strands found in the braiding in the walls appear to be threads having circular cross-sections. There is no suggestion of constructing a device using ribbon materials. Furthermore, the device is shown to be fairly stiff in that it is designed so that it may be bent using a fairly large handle at its proximal end.
U.S. Pat. No. 3,924,632, to Cook, shows a catheter body utilizing fiberglass bands wrapped spirally for the length of the catheter. As is shown in FIG. 2 and the explanation of the Figure at column 3, lines 12 and following, the catheter uses fiberglass bands which are braided, that is to say, bands which are spiraled in one direction cross over and under bands which are spiraled in the opposite direction. Additionally, it should be observed that FIG. 3 depicts a catheter shaft having both an inner lining or core 30 and an outer tube 35.
U.S. Pat. No. 4,425,919, to Alston, Jr. et al., shows a multilayered catheter assembly using multi-stranded flat wire braid. The braid 14 in FIG. 3 further covers an interior tubing or substrate 12.
U.S. Pat. No. 4,484,586 shows a method for the production of a hollow, conductive medical tubing. The conductive wires are placed in the walls of hollow tubing specifically for implantation in the human body, particularly for pacemaker leads. The tubing is preferably made of an annealed copper wire which has been coated with a body-compatible polymer such as a polyurethane or a silicone. After coating, the copper wire is wound into a tube. The wound substrate is then c
Alejandro Jose D.
Ju Byung H.
Morrison & Foerster / LLP
Nguyen Anhtuan T.
Target Therapeutics Inc.
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