Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-12-27
2003-06-10
Casler, Brian L. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S174000, C128SDIG006, C128SDIG008
Reexamination Certificate
active
06575959
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to guide, diagnostic, and therapeutic catheters for use in medical procedures. In particular, the present invention relates to an improved therapeutic micro-catheter proximal hub and method of manufacture, wherein the hub is molded around the catheter shaft over a shielding sleeve which prevents damage to the catheter shaft while assuring adequate bonding of the hub to the shaft.
BACKGROUND OF THE INVENTION
The present invention relates to the field of catheterization of lumens within the human body, particularly lumens in the cerebral, peripheral, and heart vasculature. The invention has application to the manufacture and construction of guide, diagnostic, and drug delivery catheters, as well as balloon catheters.
Many medical procedures include the insertion of a catheter into a lumen of a living body. In the performance of such medical procedures, guide catheters and diagnostic catheters are well known for use in catheterization procedures in the vascular system, such as angiography, angioplasty, and other diagnostic or interventional procedures, such as interventional radiology.
One useful therapeutic application of intravascular catheters is the treatment of intracranial aneurysms in the brain. Approximately 25,000 intracranial aneurysms rupture each year in North America. An aneurysm which is likely to rupture, or one which has already ruptured, may be treated by delivering an embolic device or agent to the interior of the aneurysm. The embolic device or agent encourages the formation of a thrombus inside the aneurysm. The formation of a thrombus reduces the probability that an aneurysm will rupture. The formation of a thrombus also reduces the probability that a previously ruptured aneurysm will re-bleed. Thrombus agents which may be used include liquid thrombus agents such as cyanocrylate, and granulated thrombus agents such as polyvinyl alcohol or alcohol. An additional type of thrombus agent which is frequently used is a tiny coil. Any of the thrombus agents described above may be delivered using an intravascular catheter.
When treating an aneurysm with the aid of an intravascular catheter, the catheter tip is typically positioned proximate the aneurysm site. The thrombus agent is then urged through the lumen of the intravascular catheter and introduced into the aneurysm. Shortly after the thrombus agent is placed in the aneurysm, a thrombus forms in the aneurysm and is shortly thereafter complemented with a collagenous material which significantly lessens the potential for aneurysm rupture. It is desirable that the lumen of the catheter provides a path for delivering embolic devices to an aneurysm. To this end, it is desirable that the pathway through the catheter have a low friction surface.
In other portions of the human body, diagnostic catheters are used for procedures including dye delivery, arterial flushing or arterial pressure monitoring. Diagnostic catheters are also used during cardiac catheterization for diagnosis of coronary artery disease, for defining vessel anatomy, for isolating lesions, and for identifying adjacent cardiac branches which may impinge on a lesion and affect ventricular function. For procedures within the coronary artery, the distal end of the diagnostic catheter is inserted percutaneously into the vascular system of the patient and pushed distally up and over the aortic arch. A proximal end of the catheter protrudes outside of the patient's body and may be used for implementation of diagnostic procedures, such as dye delivery, flushing, and arterial pressure monitoring.
Angioplasty procedures have gained wide acceptance as an efficient and effective method for treating certain types of vascular diseases. In particular, angioplasty is widely used for stenoses in the coronary arteries, although it is also used for the treatment of stenoses in other parts of the vascular system. The most widely used form of angioplasty makes use of a dilatation balloon catheter to treat a stenosis and thereby reestablish an acceptable blood flow through the artery. The dilatation catheter includes an elongated tubular shaft and an inflatable balloon carried at a distal end of the shaft. In operation, the catheter is inserted through a guide catheter which has been previously introduced into a patient's vascular system from a location remote from the heart (e.g., femoral artery). The proximal end of the guide catheter remains outside the patient while the distal end of the guide catheter is positioned at the coronary artery ostium. A dilatation catheter is introduced into the proximal end of the guiding catheter and advanced to the distal end of the guide catheter. Then, by using fluoroscopy, the physician guides the dilatation catheter the remaining distance through the vascular system until the balloon is positioned across the stenosis.
In each of the above applications, the catheter commonly includes a hub and/or manifold at its proximal end, which permits the catheter to be more easily handled, and which may incorporate a luer fitting or other connection device which may be attached to an appliance conveying a fluid media or substance which is to be delivered to the distal end of the catheter. In some known catheters, hubs are adhesively bonded to the catheter shaft, while in other known designs, hubs are injection or insert molded onto the catheter shafts. With the insert molding process, the injected molten plastic hub material, because of its high temperature, may be capable of damaging the shaft of the catheter by melting or otherwise deforming it. This may compromise the integrity of the lumen walls in the affected region which may lead to collapse by kinking or other deformation that reduces the lumen diameter.
Under prior methods of injection or insert molding hubs onto catheter shafts, the catheter shaft was afforded protection from the high temperatures of the injected hub material by protective layers placed over the catheter shafts. For example, the catheter shaft might be protected by multiple layers of polymeric films over the catheter shaft in the region of hub attachment. In order to ensure good adhesion of the catheter hub to the shaft, these multiple protective layers require separate lamination of each layer to the shaft and to each other. Accordingly, these prior methods of securing hubs to catheter shafts had a number of drawbacks. The preparation of the catheter shaft prior to hub molding increased the complexity of catheter manufacture, and the increased preparatory steps afforded increased chances for error, quality variations, and rejected products and waste, in addition to increased time and cost of manufacture.
It is desirable to have a plastic molded hub, and a manufacturing process for these hubs, which is less labor intensive than prior methods of producing such catheters with hubs, and which would have reduced defect and scrap rates relative to present techniques of securing the hub to the catheter shaft.
SUMMARY OF THE INVENTION
The present invention pertains to a process for the production of intralumenal catheters with an insert molded hub, that does not require extensive preparation of the catheter shaft prior to molding. One embodiment of the present invention provides for a tubular sleeve of material that is compatible with the hub molding media. The tubular sleeve shields the catheter shaft from heat generated during the injection molding process, but transfers enough heat for bonding the sleeve to the catheter shaft. The compatible material of the tubular sleeve thermally bonds with the shaft on the sleeve's inner diameter, and bonds with the hub molding media on the sleeve's outer diameter during the single injection molding step. The present invention overcomes disadvantages of previously existing methods for securing the hub to the catheter shaft, and accomplishes hub molding with fewer errors in manufacture. The present invention therefore increases the reliability of the production process, in addition to making the hub to catheter shaf
Alpert Lawrence C.
Jansen Lex P.
Sarge Jeffrey A.
Welsh Greg P
Casler Brian L.
Crompton, Leager & Tufte, LLC
Maynard Jennifer
Sci-Med Life Systems, Inc.
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