Abstract:
Tubular endoprosthesis for anatomical conduits is provided with a tubular body having an external surface which includes a plurality of protuberances. Preferably, the protuberances are distributed on the totality of the external surface, and are composed of nipples having a round apex, spaced from each other and radially oriented with respect to the tubular body.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention concerns a tubular endoprosthesis for anatomical conduits or channels. Specifically, particular nonlimiting embodiments of this endoprosthesis are intended to permit the clearance of hardened conduits such as the trachea or bronchus, or to serve as a support for such anatomical conduits when they prove to be weak. Also described is an instrument to put this endoprosthesis in place. 
     2. Description of Background and Relevant Information 
     A hollow tube is disclosed in French Patent Document No. 1,130,165 for the treatment of hardening of the esophagus. The device constitutes a flexible tube with a ribbed external surface intended to be installed in a tumoral contraction to permit the passage of food. 
     This hollow tube has the drawback of not offering any guarantee that it will stay in place, because it can easily turn on itself, which can provoke irritation. Such irritation generates rejection spasms leading to axial shift of the tube, along with the serious consequences to which this shift can lead. 
     SUMMARY OF THE INVENTION 
     One of the objects of the present invention is to effectively remedy this serious insufficiency of known endoprostheses. 
     According to the invention, this objective is obtained by means of an endoprosthesis with a tubular body whose external surface is provided with numerous protuberances or asperities, preferably distributed over the entire surface, or a portion thereof. These protuberances consists of nipples with rounded tops, which are spaced from each other in the longitudinal and peripheral directions on the tubular body, and are preferably radially-oriented. 
     Another advantage of the endoprosthesis according to the invention is that it can be put easily in place and installs itself in a natural, extremely resistant fashion. In its implantation position, the prosthesis cannot, in effect, turn or slide axially when it is installed in the stenosis. In addition, this prosthesis may be made of a plastic material, such as an elastomer silicone, which is well tolerated by the organism whether healthy or ill, in whom it does not produce rejection spasms or trauma. 
     In another embodiment of the tubular endoprosthesis according to the invention, the nipples are arranged in lines with spaces in between them and are oriented along the rulings of the tubular body of the endoprosthesis. 
     The nipples can also be alternatingly distributed on the external surface of the tubular body. 
     In another embodiment of the tubular endoprosthesis according to the invention, at least one of its ends has an internal slanted wall. Optionally, both or all of its ends may have an internal slanted wall. 
     The goals, characteristics, and advantages above, and others, will be more apparent from the following description and the attached Figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the tubular endoprosthesis according to the invention. 
     FIG. 2 is a lengthwise cross-section of the tubular endoprosthesis shown in FIG. 1. 
     FIG. 3 is a transverse cross-section of the tubular endoprosthesis shown in FIG. 2. 
     FIG. 4 is an enlarged view, in detail, of a lengthwise cross-section of one of the ends of the endoprosthesis. 
     FIG. 5 is a front view of an embodiment of utilizing the endoprosthesis according to the invention, to permit tracheal bronchus clearance. 
     FIG. 6 is a view of the instruments permitting the placement of an endoprosthesis like the one illustrated in FIGS. 1-4. 
     FIGS. 7-11 show the operation of the placement instrument shown in FIG. 6 and the installation method for the tubular endoprosthesis according to the invention. 
     FIG. 12 is a front view of another embodiment of a tracheal bronchus endoprosthesis according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     We refer to the following embodiments to describe the non-limiting construction of this endoprosthesis, as well as the use of instruments permitting its installation. 
     The tubular endoprosthesis according to the invention can, as a function of the shape of the anatomical conduit or channel inside which it is intended to be installed, affect a variety of shapes. Particular embodiments have a simple rectilinear or essentially rectilinear shape (for example, when it is a tracheal endoprosthesis or bronchus endoprosthesis) as shown in FIG. 1, or a curved shape. Another embodiment has a more complex shape with a principle tube extending into two divergent tubular branches (when it is a trachea bronchus endoprosthesis) as shown in FIG. 5. More precisely, this endoprosthesis can have any shape and any diameter adapted to the shape and the diameter of the conduits, channels or vessels inside which it is to be placed. The endoprosthesis can be made in any supple, semi-rigid, or rigid material, and may be reinforced by an internal reinforcement capable of being well-tolerated by the organism. Preferred embodiments can be advantageously made in a material with an elastic deformation capacity which in a particularly preferred embodiments is an elastomer silicon. 
     According to one embodiment of the invention, the endoprosthesis has a tubular body 1 with an external surface 2, which is intended to come into contact with the internal wall of an anatomical conduit. External surface 2 is provided with numerous protuberances or asperities 3, which may be distributed evenly over the entire external surface 2 or positions thereof. 
     These protuberances or asperities 3 can have very different shapes, without edges that could injure the anatomical walls with which they are supposed to come into contact. In a preferred embodiment the proterberances or asperities 3 consist of nipples with rounded tops, arranged in lines oriented according to the rulings of the endoprosthesis; these lines of nipples can be angularly spaced, as shown particularly in FIG. 1. These nipples 3 are radially-oriented in relation to the tubular body 1, and they are spaced from each other in the lengthwise direction as well as the peripheral direction. They can be advantageously distributed alternately on the lateral surface of the tubular body 1. The nipples can have a circular or any other shaped section. Also, these nipples or nibs 3 are ineffaceable, that is, they are sufficiently rigid so that they don&#39;t compress, bend, or retract under the conditions of use. 
     At least one, and preferably both ends, of the endoprosthesis are provided with an internal sloping edge 4 (FIG. 4), so that the ends consist of thin, tapered lips. This feature provides that when the endoprosthesis is in place, it forms no retention asperity favoring the formation of diverse accumulations as a function of the nature of the conduits, channels or vessels, at the entry or exit of the prosthesis. 
     The alternative embodiment of the prosthesis illustrated in FIG. 5 differs from the preceding only by its slightly more complex shape adapted to the conformation of the conduits in which it is to be installed. According to this variation of construction, the prosthesis includes a principal tubular body 1&#39; extended by two divergent tubular branches 1&#34;; the external surfaces 2&#39;, 2&#34; of the main body and of the branches are provided with nipples 3, as previously described. Such a prosthesis is intended to be placed at the branching point of an anatomical conduit. According to a very interesting application, such a prosthesis is intended to constitute a tracheobronchus endoprosthesis, allowing the conduit to remain open despite an obstruction S affecting both the internal part of the trachea T and the initial portion of the two bronchi B to be by-passed. 
     FIG. 12 shows another embodiment of a prosthesis according to the invention such as a tracheobronchus endoprosthesis, also intended to be placed at the branching point of an anatomical conduit, such as in the case of an obstruction S to be by-passed affecting only the base of the major conduit (trachea T, for example) and only one of the branches (one of the bronchi B&#39;, for example). In this case, the prosthesis has a curved shape and includes a major part 10 extended by a second part of smaller diameter 10&#39;. In addition, it has an opening 9 laterally placed at the juncture point of the major part 10 and secondary part 10&#39;, the opening 9 is intended to be placed at the entry of a second healthy branch of an anatomical conduit (the other bronchus B&#34;, for example), in order to permit a passage between the principal conduit T and a healthy branch B&#34;. 
     The lateral opening 9 can also allow and favor the installation of a second independent tubular branch similar to the secondary part 10&#39;, in order to create an endoprosthesis like the one shown in FIG. 5. 
     We have shown in FIG. 6 an installation or introduction instrument for endoprosthesis consisting of a rectilinear or essentially rectilinear tube such as those which are intended to be installed in the trachea or in the weak, hardened or tumor-compressed bronchi, in order to serve as their support or to permit them to be cleared. 
     This instrument includes a classic bronchoscope 6 on the elongated cylindrical body or guidance rod 6a, on which is mounted, with a sliding ability in relation to said rod, a tubular pusher 7 whose length L&#39; is less than the length L of the guidance rod 6a. The difference in length between the rod 6a of the bronchoscope and the pusher 7 corresponds at least to the length L&#34; of the endoprosthesis 8 intended to be introduced and positioned with the help of the instrument; this difference in length (L--L&#39;) being, however, preferably greater than the length L&#39; of the endoprosthesis. 
     FIGS. 7-11 show the installation procedure of a simple endoprosthesis 8 in an anatomical conduit B (for example, trachea or bronchus) obstructed by a compressive tumor S. 
     The endoprosthesis 8 is first placed around the end of the rod 6a of the bronchoscope 6, in front of the pusher 7 (FIG. 7), the tapered end of the rod emerging at the front of the endoprosthesis, in order to facilitate its progress in the anatomical conduit. 
     The rod furnished with endoprosthesis 8 is then introduced and driven into the anatomical conduit B (FIG. 8) until said endoprosthesis reaches the desired position (FIG. 9), that is, the place where the hardening or compressive tumor is located. 
     The rod 6a of the bronchoscope is then withdrawn while maintaining the pusher 7 in place, which prevents any backwards movement of the endoprosthesis during this withdrawal (FIG. 10). Finally, the pusher is withdrawn, the endoprosthesis then being installed and solidly fixed in its lodging because of the nipples provided on its external surface, on which the surrounding anatomical wall exerts pressure preventing any shift or movement of the endoprosthesis.