Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-11-17
2003-09-09
Capossela, Ronald (Department: 3744)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S103090, C606S194000
Reexamination Certificate
active
06616651
ABSTRACT:
BACKGROUND OF THE INVENTION
The subject invention is directed toward the art of vascular catheters and to catheter manufacturing methods and, more particularly, to intravascular microcatheters of unitary construction provided with an integral continuous coiled wire reinforcement member, and to improved methods and apparatus for manufacturing multiples of such catheters from a continuous feedstock.
Angiographic catheters have been widely used for diagnostic purposes such as in conjunction with the injection of dyes or the like into arteries for the visualization of obstructions, ruptures, or other malformations. Diagnostic catheters are typically constructed with an embedded layered wire braid reinforcement system surrounding the lumen to provide torsional control and to strengthen the catheter body to better withstand high pressure injections.
Catheters of the type described above are shown in my prior U.S. Pat. No. 3,485,234, which issued Dec. 23, 1969. My prior U.S. Pat. No. 3,585,707, which issued Jun. 22, 1971 sets forth generally a method of manufacturing wire braid type angiographic catheters. In addition, my prior U.S. Pat. Nos. 5,738,742 and 5,972,143 describe how to manufacture a plurality of diagnostic catheters having unitary body and tip sections from a continuous feedstock. The teachings of the above prior patents are incorporated herein by reference.
It is likely that wire braid construction will continue to be useful in larger diameter catheters such as in the size range French 8 through French 4. However, in modern medical practice, the use of catheter device has been broadened to embrace many forms of interventional therapy. As examples, catheters are presently used in connection with placement of dilation balloons for opening obstructed coronaries and other vessels, for the placement of stints to “prop” open vessels, for introduction of anticoagulants to dissolve clots, and for introduction of coagulants to form clots to “plug” aneurysms or to seal off vessels feeding malignant tumors. The target vessels in the above procedures are typically located in the smaller vessels of the brain, kidney, liver, heart, and other organs. Braided wire catheters, however, are not well suited for applications that require a catheter size of French 3 or smaller. There is a need, therefore, for much smaller catheters that can be extended into the smaller target vessels.
One solution is to construct a catheter that uses a coiled wire reinforcement member within the catheter body as an alternative to the braided wire reinforcement construction scheme. Although the coiled wire construction results in some loss of torsion control, a significantly thinner overall catheter body is enabled. Catheters that include integral coiled wire members have an overall good pushability characteristic and typically do not kink as readily as braided wire construction catheters of the same diameter using the same wire diameter.
Another advantage is that coiled reinforcement wire catheters can provide a larger lumen size than braided wire type catheters relative to overall catheter body size. Since the reinforcement wire is overlapped in the braided construction as it is braided onto the inner catheter wall construction, the overall reinforcement layer thickness is at least twice as large as in the non-overlapping coiled wire type catheter using the same wire diameter.
U.S. Pat. Nos. 5,733,400 and 5,662,622 teach an intravascular catheter carrying a helical reinforcement member embedded within at least a portion of a tubular wall of the catheter. The catheter body is formed from separate sections which are connected end to end to provide successively increasing flexibility zones from the proximal end toward the distal catheter end. The catheter body is thin and therefore particularly capable of being advanced into small areas such as brain arteries for example, so that therapeutic agents may be delivered to locations deep inside the brain, which locations would be inaccessible to many other catheters.
However, the catheter taught in the above patents is expensive because the manufacturing method is very labor intensive. More particularly, turning to the flowchart illustrated in
FIG. 1
, the prior art manufacturing process
10
includes the steps of joining together a pair of tubular catheter reinforcement members in end-to-end, abutting relation
12
. Next, in step
14
, a UV curable adhesive is placed on the joined ends. In step
16
, the joined ends are covered with a snug, non-adherent transparent sleeve. The adhesive is cured in step
18
and, thereafter, in step
20
, the cover sleeve is removed. Additionally, preferably, the adhesive is cured using ultraviolet light and, accordingly, the sleeve is formed of a substantially ultraviolet radiation transparent material. In step
22
, the joined reinforcement members are embedded into a tubular plastic catheter wall.
One major disadvantage of the catheter construction and method taught in the above patents is that the manufacturing method is highly time consuming and labor intensive. Further, the overall catheter assembly could be prone to failure because it is formed of a plurality of joined individual parts.
Accordingly, it would therefore be desirable to provide an interventional therapy type catheter having a continuous coil reinforcement member and that is of a substantially unitary construction. Further, it would be desirable to provide methods and apparatus for manufacturing multiples of such catheters from a single feedstock using a continuous process. In order to reduce manufacturing cycle time, it is desirable to wind the reinforcement wire directly onto the inner substrate layer of the catheter body in a continuous manner and, thereafter, apply one or more subsequent catheter body layers to produce a large number of catheters from a single feedstock in an efficient manner with minimal labor demands.
SUMMARY OF THE INVENTION
The subject invention provides a unitary intravascular microcatheter with a continuous embedded helical coil reinforcement member and methods and apparatus for manufacturing same at a reduced manufacturing cost by enabling multiple catheters to be manufactured from a continuous feedstock. The overall construction of the subject microcatheter device is unitary, making the subject device less prone to failure and easy to manufacture in multiples. The embedded reinforcement member forms a continuous helical path along the length of the microcatheter with a selected variable pitch angle to control the stiffness of the microcatheter at various portions. The pitch of the reinforcement member winding is selectively varied along the length of the catheter to provide a smooth transition between different catheter stiffness regions.
In accordance with a preferred aspect of the invention, there is provided methods and apparatus for manufacturing multiple catheters from a continuous feedstock. A selected length of an elongate cylindrical tube is provided, preferably, carried on an inner wire mandrel to prevent the tube from collapsing during the various manufacturing operations. A first selected length of the cylindrical tube is held stationary between a pair of spaced apart chuck members. A lead end of a reinforcement wire is spot-bonded to the tube and then wrapped onto the stationary portion of the first selected length of the cylindrical tube. The trailing end of the reinforcement wire is thereafter spot-bonded tothe tube. The wire wrapped portion of the cylindrical tube is then advanced relative to the pair of spaced apart chuck members to hold a second selected length of non-wire wrapped cylindrical tube stationary between the pair of chuck members. The reinforcement wire is then spot-bonded and wrapped onto a portion of the second selected length of the cylindrical tube held between the spaced apart chuck members using the procedure described above. The steps of advancing the cylindrical tube through the chuck members and then wrapping the reinforcement wire onto the tube is repeated for substantially the entire length o
Capossela Ronald
Fay Sharpe Fagan Minnich & McKee LLP
LandOfFree
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