The Van Tassel et al Patent taught the attachment of a soft balloon like tip to ends of catheters. But it was not a method that could be used for attachment to reinforced walls because it required step cutting of the catheter wall. 15
The Alston, Jr. et al Patent positioned flat wire braiding between layers of material. This required thick walls in proportion to diameter of catheters. Separation of the layers was problematic for thin walls with that type of construction. It was not a monolithic type of wall 20 taught by this invention.
The Cook Patent employed conventional sandwiching of fiberglass woven roving between plastic layers of tubing. Walls were far too thick for the conveyance efficiency required for current medical practices. 25
The Polanyi et al Patent combined a wide variety of catheter features in a catheter wall. But the constructional form was far too thick and the cost of construction too high in comparison to present catheters. It was one of the first catheters to utilize fiber optics, but in 30 forms that have been superseded with smaller and more efficient fiber optics and diagnostic equipment made possible with this invention. Its walls and linear components would separate if made sufficiently thin for current catheter applications. 35
SUMMARY OF THE INVENTION
In accordance with the present invention, it is contemplated that one objective of this invention is to provide a catheter with a high ratio of torque transmittal 40 capacity from end-to-end for accurate and reliable rotational positioning of a guiding tip at a distal end of the catheter.
Another objective is to provide selective resilience and circumferential torque transmission at different 45 linear portions of a catheter.
Another objective is to provide high lubricity of both inside and outside peripheral surfaces of a catheter.
Another objective is to provide perfusion ports at select portions of a catheter without weakening torque 50 transmission, cylindrical integrity, structural integrity, flexibility or resilience of a catheter.
Another objective is to provide a catheter having thinner walls and a smaller outside diameter in proportion to inside diameter than present catheters. 55
Another objective is to provide a soft and smooth catheter tip immediately at the distal end of either progressively decreased or continued reinforcement density of a catheter.
Yet another objective of this invention is to provide 60 methods for constructing catheters having characteristics provided by this invention.
This .invention accomplishes the above and other objectives with a catheter having strands of resilient reinforcement material integrally spiraled or braided 65 into monolithic walls of flexible material. A solid lubricant, also referred to as dry lubricant, comprised of either special fluorine containing materials or polymeric
organic silicon compounds is embedded into interior and exterior wall surfaces of the catheters. Smooth interior walls are channeled to decrease friction resistance, to trap resistance particles and to dissipate friction heat in the high ratio of surface area to cross-sectional area of small catheters. Number of spirals or braids of reinforcement strands per unit of length, number of layers of strands of the catheters, catheter diameter and progressiveness thereof are designedly different for separate portions of particular catheters. Catheter tips are weldable immediately adjacent to select density of strands of reinforcement material. Perfusion ports are weldable where desired. Directional bends are positional selectively at distal ends of the catheters. Methods for manufacture and modification with co-extrusion, miniature milling and welding while maintaining structural integrity with monolithic wall structure are described.
Other objects, advantages and capabilities of the invention will become apparent from the following description taken in conjunction with the accompanying drawings showing preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cutaway side view of a luer and proximal end section of a catheter using this invention;
FIG. 2 is a distal end and tip of a catheter using this invention;
FIG. 3 is a cutaway sectional view of a catheter with reinforced monolithic walls in an embodiment of this invention;
FIG. 4 is a cutaway side view of prior art using layered rather than monolithic walls;
FIG. 5 is a cutaway side view of a monolithic wall with a ridged inside wall in an embodiment of this invention. It is positioned immediately beside the prior art which is so labeled for ease of comparison;
FIG. 6 is a layout of co-extrusion construction of this invention. Stages of construction of the catheter in select embodiments are related to co-extrusion steps shown in FIGS. 6a through 6h.
FIG. 6a is the first stage of production of the catheter showing a cross-section of the mandrel;
FIG. 6b is a stage of production at the first extrusion die which extrudes a first portion of the catheter wall;
FIG. 6c is the stage of production where one or more strands of inside reinforcement are wrapped onto the outside diameter of the first portion of the catheter wall;
FIG. 6d shows a stage of production of the second extrusion die which is employed to extrude a second portion of the catheter wall;
FIG. 6c shows the production stage of the catheter tube being provided with friction reduction channels in accordance with the invention;
FIG. 6/is the production stage showing a third extrusion die employed to extrude additional molten catheter material infused relationship to the existing catheter wall;
FIG. 6g shows a production step employing a linear positioner to position linear diagnostic components;
FIG. 6h is a production step showing the covering of the diagnostic components of the stage of FIG. 6g with additional material extruded from a fourth extrusion die;
FIG. 7 is a section of etched mandrel of an in place type employed for particular spiral or opposite direction spiral embodiments of this invention;