Method of controlling penile prosthetic expansion

This application is a continuation claiming priority from related U.S. application Ser. No. 09/306,846 filed May 6, 1999 now U.S. Pat. No. 6,386,492.

The present invention relates generally to fabrics used with prosthetics and particularly relates to fabrics used with penile prostheses.

Various types of penile prosthesis are currently available to cure or compensate for impotence, two of which include a non-inflatable, semi-rigid implantable prosthesis and an inflatable, implantable prosthesis. The non-inflatable, semi-rigid prosthesis is implanted within the corpora cavernosa of the penis and provides a generally constant erection. The inflatable prosthesis is also implanted in the corpora cavernosa but is connected to a hydraulic pumping device. The hydraulic pumping device is located within the patient's body and is used to inflate the prosthesis for erection and deflate the prosthesis for flaccidity.

Inflatable, implantable prostheses commonly include a cylindrically shaped pressure chamber made of silicone and a pump that is used to inflate or deflate the chamber. The chamber is encapsulated in a sleeve or sheath of biocompatible material (e.g fabric) that constrains the expansion of the silicone pressure chamber.

One of the drawbacks occasionally observed with this type of inflatable prosthesis is the presence of weak spots in the sheath or fabric that surrounds the pressure chamber. Such weak spots are typically caused by separation in the texture of the fabric that can occur upon inflation of the chamber. Such separation can be particularly acute in the “hinge area” of the chamber. As a result, an aneurysm or bulge can develop in the pressure chamber extending into the separation in the fabric and the region where the pressure chamber folds on itself in the deflated condition, sometimes referred to as the “hinge region,” thereby compromising the integrity and/or physical appearance of the prosthesis.

Therefore, it is desirable to provide a fabric for an implantable prosthetic and particularly an inflatable, implantable penile prosthesis that reduces the occurrence of or eliminates pressure chamber aneurysms without compromising the other advantageous attributes of the fabric, including tensile strength, fabric thickness or fabric width.

In view of the foregoing, it is an object of the present invention to overcome the deficiencies of existing fabrics used with inflatable, implantable prostheses.

It is a further object of the present invention to provide a penile prosthesis fabric that minimizes the occurrence of chamber aneurysms without compromising tensile strength, fabric thickness or fabric width.

It is a further object of the present invention to provide a penile prosthesis fabric with increased fabric weave density.

The present invention attempts to address these objects and other objects not specifically enumerated herein through the use of a fabric used with an implantable prosthesis comprising first denier one-ply warp yarns and second denier two-ply fill yarns having the ability to expand and contract, wherein the second denier is higher than the first denier. In addition, the number of warp yarns and fill yarns provide a high fabric weave density.

FIG. 1 is a cross-sectional view of a penile prosthesis covered in a fabric in accordance with a preferred embodiment of the present invention;

FIG. 2 is a perspective view of a prosthesis fabric in accordance with a preferred embodiment of the present invention;

FIG. 3 is a perspective, partly enlarged view taken along section -3- of FIG. 1 of a prosthesis fabric in accordance with a preferred embodiment of the present invention;

FIG. 4 is a perspective view of a strand used in a fabric in accordance with a preferred embodiment of the present invention; and

FIG. 5 is a perspective view of a two-ply fiber used in a fabric in accordance with a preferred embodiment of the present invention

Referring to FIG. 1, an inflatable penile prosthesis 11 includes a cylindrically shaped pressure chamber 13 , typically made of silicone, and a pump 17 used to inflate or deflate the chamber 13 . The chamber 13 is covered in a sleeve or sheath of biocompatible fabric 10 that constrains the expansion of the silicone pressure chamber 13 .

An embodiment of a fabric 10 used with an inflatable penile prosthesis or other similar device in accordance with the present invention is shown in FIGS. 2 and 3. The fabric 10 is comprised of a weave of warp yarns 12 and pick or fill yarns 14 . Fill yarns 14 run along the width or circumference of the fabric 10 . Warp yarns 12 run in the length-wise direction of the fabric 10 . As shown in FIG. 3, the warp yarns may be smaller relative to the fill yarns 14 . In a preferred embodiment, the fabric 10 is applied to the penile prosthesis so that the fill yarns 14 circumscribe the girth of the prosthesis and the warp yarns 12 extend along the length of the prosthesis.

For use in an inflatable penile prosthesis, the fabric 10 must allow for repeated radial or girth expansion and contraction according to the intended use of the device. The fabric 10 must also provide, however, an evenly distributed constraint to the prosthetic so that the device does not inflate into an undesirable configuration. Accordingly, a combination of materials, typically spandex and polyester, are used as the fibers spun to make the warp and fill yarns 12 , 14 . Spandex is the generic name for a synthetic fiber or yarn that offers durability and good stretch and abrasion resistance. Similar to spandex, polyester is also a synthetic fiber, and is commonly characterized by its quick drying time, high strength abrasion resistance, and crease resistance. In the context of a penile prosthesis, the spandex primarily provides the elasticity in the fabric 10 necessary for expansion of the prosthesis and the polyester primarily provides the structural integrity to the fabric 10 .

Referring to FIG. 4, one element or covered yarn 15 of the fill yarn 14 used in a preferred embodiment is shown and includes a 40 denier polyester fiber 16 wrapped or coiled around a 70 denier spandex fiber 18 . Denier is a measurement of fiber weight used to express the yield, or thickness, of a thread or yarn (e.g. 1 denier=1 gram per 9,000 meters). For example, a particular material of high denier, such as 70, would have larger fibers and stronger material characteristics than that same material of small denier, such as 40, which would have finer fibers and lesser yields.

The amount of expansion of the covered yarn 15 is directed by the number of turns of polyester fiber 16 per inch of spandex fiber 18 (termed “turns per inch” or tpi). For example, a covered yarn 15 having 6 tpi would have more constrained expansion than a covered yarn 15 having 20 tpi. The covered yarn 15 of the present invention has approximately 19-25 tpi, and preferably has 22 tpi.

As shown in FIG. 5, the fill yarn 14 used in a preferred embodiment includes two covered yarns 15 which are positioned parallel to each other. The fill yarn 14 may be characterized as a two-ply yarn insofar as it uses two covered yarns 15 .

Referring to FIG. 3, the warp yarns 12 of a preferred embodiment are made of a 40 denier polyester fiber 16 . The relatively non-distensible polyester fibers 16 that comprise the warp yarns 12 limit or, in certain embodiments, even prevent elongation of the woven fabric 10 and, thus, also prevent elongation of the penile prosthesis along its axis. The denier of the warp yarns 12 also provide, however, sufficient density so that the longitudinal tensile strength of the fabric 10 is not compromised during inflation of the prosthesis.

In view of the above, it is evident that a preferred embodiment of the present invention provides a biocompatible fabric 10 having anisotropic properties such that the fill yarns 14 and warp yarns 12 of the fabric 10 allow for radial expansion, but substantially prevent longitudinal expansion, when assembled on a penile prosthesis.

The particular fill yarns 14 and warp yarns 12 comprising the fabric 10 of the present invention must be made of an appropriate material and have sufficient weight or denier so as to resist fabric distortion, such as fill separation. Although a preferred embodiment of the present invention includes a plied fill yarn 14 comprising two covered yarns 15 using a 70 denier spandex fiber 18 wrapped with a 40 denier polyester fiber 16 and a warp yarn 12 made of a 40 denier polyester fiber. Other fiber weights and materials may also be used provided that the fiber configurations and materials provide for radial expansion yet sufficiently resist fabric 10 distortion.

Fiber weight or density can be decreased by texturizing the fibers via a heating process. Texturization is commonly used in the textile industry to provide greater thickness and increased flat width to fabrics. In addition, the use of texturization also improves the weaving process of the fabric to avoid a “terry-cloth” phenomenon. In a preferred embodiment of the present invention, the 40 denier polyester fibers 16 of the fill yarns 14 have been texturized to arrive at the desired yarn strength and density.

In addition to fiber weight or denier, adequate fabric weave density may also reduce the occurrence of fabric distortion. Fabric weave density is typically defined by the warp count and fill count of the fabric. For the fabric 10 of the present invention, the warp count may range from approximately 267 to 269 and is preferably 269. In addition, the fill count is preferably 68 picks per inch, but may be within the range of 66 to 68 picks per inch. The fabric weave density should be configured so as to provide sufficient fabric thickness and flat width without compromising the structure or function of the penile prosthesis.

The particular fiber characteristics and weave density of the fabric 10 of the present invention provide a smooth, pattern-free material. Due to its pattern-free surface, the fabric 10 is less susceptible to material distortions, such as fill separation. Further, the distinct yarn characteristics of the fabric 10 allow the fabric 10 to repeatedly stretch and then return to its original shape without causing residual runs or creases in the fabric 10 .

The foregoing description addresses embodiments encompassing the principles of the present invention. The embodiments may be changed, modified and/or implemented using various types of arrangements. Those skilled in the art will readily recognize various modifications and changes which may be made to the invention without strictly following the exemplary embodiments and applications illustrated and described herein, and without departing from the scope of the invention which is set forth in the following claims.