Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent structure
Reexamination Certificate
2001-07-06
2003-06-10
Willse, David H. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent structure
C623S023640
Reexamination Certificate
active
06576008
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to methods and devices usable to place a stent in an anatomical constricting structure, such as, for example, a sphincter, using an easily-inserted and easily-withdrawn, self-stabilizing stent.
2. Description of Related Art
Prostheses usable to provide an artificial passage in anatomical tracts, such as, for example, the urinary, respiratory, digestive, gynecological or vascular tracts, in a living being are known. For example, an endo-urethral prosthesis for a human is known to have a tubular element whose walls are made from a relatively smooth and soft bio-compatible material, for example a silicone rubber, at least in its outer part. Such a tubular element is sufficiently flexible to conform to the anatomical profile and movements of, for example, a human urethra, while providing sufficient rigidity that the tubular element will not collapse under the influence of the anatomical profile or movements of the urethral tract.
As disclosed in FR-A-2 667 783, a tubular element, as described above, is placed in the urethra without passing through the striated muscles that form the sphincter in the urethral tract. The tubular element is supported primarily by the elasticity of the tubular element and the compressive force of the urethral wall. If the tubular element's diameter is large enough, the compressive forces of the elastic urethral wall may adequately secure the tubular element in the urethral tract. However, if the tubular element is too large, damage to the urethral wall may occur and withdrawal of the tubular element may be painful to the patient.
Alternatively, a smaller-diameter tubular element may be used, with notches formed in the outer wall of the tubular element, to provide a degree of secondary support for the tubular element within the urethral tract. However, such notches do not prevent the tubular element from moving downward, or descending, in the urethra during micturition, for instance. The changing position of the tubular element renders the tubular element problematic and risks discomfort to the patient. Further, providing the tubular element with scales, or fastening catches, to counter the tendency of the prosthesis to descend during micturition does not prevent the prosthesis from moving upward, or ascending, in the urethral tract as a result of routine bodily motions or functions. Such scales, or fastening elements also generate increased discomfort to the patient during withdrawal of the tubular element.
Other known catheter-delivered prostheses that provide an artificial passage in an anatomical tract of a living being include very flexible, spirally coiled metal elements. However, the flexible quality of the spirally coiled elements prove very unstable during insertion as the more rigid delivery catheter ends where the flexible element begins. As a result, bunching or other inappropriate placement of the flexible member often occurs, requiring withdrawal and re-insertion of the prosthesis, and/or causing discomfort to the patient due to the ill-configured element.
Still other known catheter-delivered prostheses that provide an artificial passage in an anatomical tract of a living being require ultra-sound, radioscopy, or other indirect visualizing devices to determine when and whether the prosthesis is in position to provide the artificial passage desired without inhibiting the natural constricting function of the anatomical constricting structure against the anatomical tract.
Thus, known tubular element prostheses are not self-stabilizing across a anatomical constricting structure. Nor are known prostheses provided with a method for inserting the prosthesis into and withdrawing the prosthesis from an anatomical tract that minimizes the pain and discomfort typically associated with stenting. Similarly, known prostheses do not have structures that provide a direct method for determining whether the catheter-delivered prosthesis is in the appropriate position in the anatomical tract such that the artificial passage is created without inhibiting the natural constricting function of the anatomical constricting structure against the anatomical tract.
SUMMARY OF THE INVENTION
This invention provides stent assemblies and methods usable to insert and withdraw a self-stabilizing prosthetic stent to or from an anatomical tract of a living being.
This invention separately provides stent assemblies and insertion/withdrawal methods that allow the self-stabilizing prosthetic stent to create an artificial passage within the tract in a manner that minimizes pain and discomfort to the living being.
This invention separately provides stent assemblies and insertion/withdrawal methods that enable a user to determine directly when the self-stabilizing prosthetic stent is properly placed.
In various exemplary embodiments, the self-stabilizing prosthetic stent comprises distal and proximal segments connected to one another via a flexible connection structure to form an approximately continuous outer surface of the self-stabilizing prosthetic stent. The approximately continuous outer surface of the self-stabilizing prosthetic stent permits non-traumatic insertion or withdrawal of the self-stabilizing prosthetic stent to or from an anatomical tract of a living being without needing anesthesia. In various exemplary embodiments, the distal and proximal segments are generally tubular elements that can be formed of a relatively smooth, soft bio-compatible material. This permits the distal and proximal segments to conform to the profile and movements of the anatomical tract that the self-stabilizing prosthetic stent is placed within. In various exemplary embodiments, each of the distal and proximal segments have a substantially constant cross-section.
In various exemplary embodiments, the self-stabilizing prosthetic stent's flexible connection structure includes a tubular, flexible sleeve having opposed first and second ends. The first end of the flexible connection structure connects to the self-stabilizing prosthetic stent's distal segment. The second end of the flexible connection structure connects to the self-stabilizing prosthetic stent's proximal segment. The flexible connection structure, when properly seated, lies adjacent to the anatomical constricting structure of the anatomical tract. The flexible quality of the flexible connection structure permits the natural function of the anatomical constricting structure to continue, thus creating the desired artificial passage in the anatomical tract.
In various exemplary embodiments, the stent assembly usable to insert and withdraw this self-stabilizing prosthetic stent structure includes one or more additional structural features permitting the insertion and withdrawal methods of the invention to be achieved.
In various exemplary embodiments, inserting the self-stabilizing prosthetic stent uses a delivery catheter, on which at least a portion of the self-stabilizing prosthetic stent is placed, to generally guide the self-stabilizing prosthetic stent into an anatomical tract. In various exemplary embodiments, the delivery catheter includes a semi-rigid, hollow mandrel usable to urge the distal stent segment into the anatomical tract, and a pusher to push the proximal stent segment, in a trailing fashion relative to the distal stent segment, to the desired position within the anatomical tract.
In these exemplary embodiments, the pusher is first placed upon the mandrel. The self-stabilizing prosthetic stent is then mounted upon the mandrel. The self-stabilizing prosthetic stent is then placed into the anatomical tract such that a generally closed end of the distal stent segment enters the anatomical tract first. The flexible connection structure joins the distal stent segment to the proximal stent segment and also is mounted upon the mandrel. Mounting the self-stabilizing prosthetic stent in this manner upon the mandrel precludes the flexible connection structure from deforming until after the mandrel is withdrawn. The hollow mandrel
Devonec Marian A.
Lehman John W.
Paddock Kimberly A.
Rioux Robert F.
Blanco Mavier G.
Oliff & Berridg,e PLC
Sci-Med Life Systems, Inc.
Willse David H.
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