WO1993020779A1

WO1993020779A1 - Urethral prosthesis

Info

Publication number: WO1993020779A1
Application number: PCT/FR1992/000321
Authority: WO
Inventors: Jean-Pierre Martial Berberian
Original assignee: Berberian Jean Pierre Martial
Priority date: 1990-10-11
Filing date: 1992-04-10
Publication date: 1993-10-28
Also published as: FR2667783A1; FR2667783B1

Abstract

A urethral prosthesis consisting of a generally cylindrical flexible tubular member (1) made of a biologically acceptable elastomer. The flexible tube (1), from which a longitudinal strip has been cut out, may be placed in a urethra with its two longitudinal edges (4a, 4b) together. Said tube is held within the urethra by the tube (1) itself, as it tends to open out on either side of the median line of its longitudinal opening, and thereby provides at the same time a communicating passageway between the inside of the tube (1) and the urethra.

Description

URETRAL PROSTHESIS

The present invention relates to a urethral prosthesis, which can be left in place in a patient for a relatively long time without discomfort for the latter.

In Figure 1 of the accompanying drawing, there is shown in its entirety a urethra to define the different zones, it being understood that a prosthesis according to the invention can be either an intraprostatic prosthesis or a prosthesis intended for the penile urethra or certain areas of that penile urethra. The urethra communicates the bladder 201 with the outside, the urinary canal opening to the outside through the meatus 102. From the bladder, the urethra first comprises the intra-prostatic urethra 103 disposed between the sphincter smooth 104 and the striated sphincter 105, the intraprostatic urethra passing between the prostatic adenomas 106. Just upstream of the striated sphincter 105 is the veru montanu 109, which constitutes a slight protuberance inside the urethra, on the lower area of it. Following the intraprostatic urethra 103 is the penile urethra which includes the anterior penile urethra 107 and the posterior penile urethra 108, the latter being itself divisible into a membranous urethra 108a and the bulbar urethra 108b. The membranous urethra 108a is on the side of the striated sphincter 105; the bulbar urethra 108b is located between the membranous urethra 108a and the anterior penile urethra 107. The bulbar urethra 108b has a U shape and has an enlargement in the zone of the soul of the U. The anterior penile urethra 107 is connected to the bulbar urethra 108b by a U-shaped elbow.

Generally, the urethra may be subject to narrowing, either in the prostate by enlarged prostate adenomas, or in the level of the penile urethra.

The narrowing of the penile urethra requires surgical intervention so that the urethra can recover a normal diameter allowing the urine flow to flow under satisfactory conditions. This procedure consists in making longitudinal incisions radially of the external wall of the urethra, so that it can again dilate. The temporary placement of a probe then allows a certain recalibration of the urethra; this probe must remain at least a week, and even longer, preferably, otherwise the recurrence is almost certain. It is desirable, in fact, to maintain the probe beyond the time of healing of the urethra.

Conventionally, such a probe consists of a tube, one end of which includes a balloon. This catheter is introduced into the urethra, deflated balloon, until the latter enters the bladder; then the balloon is inflated by means of a conduit placed in the tube, by blowing air or water; thus, the catheter is held in place by the inflated balloon, which is placed above the smooth sphincter of the bladder. The extraction of the probe is carried out by sucking in the balloon duct the air or water, which has been introduced therein, so that ^"the probe can ^* come out by reverse sliding from that carried out for its introduction. Unfortunately , this probe does not allow the urinary sphincters, which it crosses, to play their role; this implies that the patient is carrying a urinary bag, since the urine flows continuously.

As a result, such a probe can only be left in place for three to eight days, too short a duration to significantly rule out the risk of recurrence. In order to eliminate the drawback represented by the wearing of urine bags and therefore to allow the urinary sphincters to fully fulfill their role, we have already used, as prosthesis, a tube, which is introduced only into the penile urethra, without penetrating in the bladder, and the end of which arrives substantially below the striated sphincter without passing through it: therefore, it is necessary to provide means for holding this prosthesis in place. The outer wall of the prosthesis tube therefore has pins, which fold along the tube, when it is inserted into the "urethra, and deploy as soon as the tube is put in place. cooperating with the internal wall of the urethra, they allow the prosthesis to be held in place, however, such a prosthesis has a certain number of drawbacks: due to the presence of the pins, the diameter of the tube is much less than that of the urethra, which leads to risks of blockage and improper recalibration of the urethra; moreover, the action of the pins on the internal wall of the urethra causes, after a relatively short time , pain requiring removal of the prosthesis.

In these two types of prosthesis and probe, there are generally no holes in the wall of the tube, that is. troublesome for the elimination of secretions emitted by the wall of the urethra and which facilitates the ejection of the prosthesis.

In an attempt to remedy these drawbacks, the applicant has proposed, in his French patent n ^β 2 611 486, a prosthesis for the penile urethra constituted by a flexible tube of length substantially equal to that existing between the striated sphincter and the orifice external of the urinary canal, this tube being intended to have its upstream end, with reference to the direction of the urinary flow, located under the striated sphincter urinary. According to this embodiment, openings are formed, all along the tube, in the zone of the tube located in the vicinity of the generator, called the ventral one, of this tube, which is intended to be in contact with the ventral wall of the urethra ( i.e. the lowest zone). Each opening constitutes a whistle notch _r whose mean plane is oblique with respect to the axis of the tube in the zone of the opening, the upstream edge of the notch forming a beak intended to cooperate with the inner ventral wall of the urethra when the prosthesis is in place.

This urethral prothe.se lets the urinary sphincters fully fulfill their function; the presence of openings in the wall of the tube allows secretions from the urethra to be evacuated; and the attachment of the prosthesis by the beaks which the upstream edges of the whistled notches seem to be less annoying for the patient than the pins of the previous embodiment recalled above. However, the drawback has appeared that the patient often feels pain when seated, because, in this position, pressure is exerted on the ventral area of the prosthesis, and the attachment beaks, than the ventral area of the tube has, subjected to this pressure, cause pain in the patient. At the same time, it has been observed that the prosthesis generally tends to be ejected too quickly.

One can then imagine placing the openings constituting the notches as a whistle on the dorsal region of the tube; such an embodiment is however not satisfactory because the attachment is less well achieved and the tendency to eject the prosthesis is even stronger than in the case of the arrangement of the openings on the ventral area.

Depending on the patient, it can therefore be desirable, in the event of narrowing of the urethra, to put in place either an intraprostatic prosthesis disposed between the sphincters 104 and 105, or a penile urethra prosthesis extending over the entire length between the striated sphincter 105 and the meatus 102, a partial prosthesis intended for cer¬ tain parts of the penile urethra and in particular the bulbar urethra or the elbow of the anterior penile urethra. The depositor sought to solve the problem of ensuring good attachment of the prosthesis without risk of ejection without causing any pain for the patient, while retaining the advantage of the presence of openings allowing evacuation necessary secretions from the urethra.

According to the present invention, it proposes the solution consisting in using, to constitute a prosthesis intended for the penile or prostatic urethra, a flexible tube, of naturally cylindrical shape, from which a longitudinal strip has been removed, and which, when it is in place in the urethra, with its free longi¬ tudinal edges close together, the tendency of the tube to return to its cylindrical shape making it possible to keep it in place in the urethra. In the position of use, the aforementioned area of the close free edges is arranged while facing the ventral area of the urethra, which is the most sensitive area and which is therefore not hampered by nozzles as was the case. case in the aforementioned prior art. Complementary attachment means can be provided without drawbacks on the rest of the tube. Furthermore, the aforementioned edges tending to move apart, in order to restore the tube to its natural shape, this ensures communication between the interior of the prosthesis tube and the urethra, for the evacuation of secretions from it. In addition, the best choice of tube thickness results from a compromise between a small thickness, which allows a larger internal diameter of the tube, favoring the passage of urinary flow, and a large thickness, which ensures a high tendency of the tube to return to its original shape due to its own elasticity.

We had already proposed, in the British patent application GB-A-2 227 175, a prosthesis consisting of a plate of elastic material comprising perforations and external reliefs for attachment. But such a flat plate must necessarily be constrained to constitute a tubular element capable of being put in place by introduction from the urinary meatus: the tubular shaping of this plate requires a short length of prosthesis, which explains why such a prosthesis was only proposed for the intraprostatic urethra. In addition, the external attachment reliefs are supported on the urethral wall and thereby reduce the section available for the duct delimited by the shaped plate, that is to say the section of the urinary duct after placement of prosthesis; the passage section is much smaller than that of the urethra from which there is a risk of plugging. Finally, and above all, the elastic return of the planar plate is effected by distending the urethra in the direction of the width of the plate with an excessive support of the plate edges on the uretral wall due to the fact that the end of the return élas¬ tick would correspond to a return of the plate to the planar state; there will therefore be a bracing of the edges of the plate inside the urethra, hence permanent pain for the patient. On the contrary, the solution proposed according to the invention avoids all these drawbacks. The elastic return of the prosthesis according to the invention reduces it to a tubular and non-planar shape, so that the elastic support of the prosthesis on the urethra is never made by bracing on an edge but, on the contrary, over the entire external surface of the tubular element used. The prosthesis according to the invention is therefore much better tolerated by patients than a prosthesis according to GB-A-2 227 175.

The present invention therefore relates to the new industrial product that constitutes a urethral prosthesis constituted by a flexible tubular element produced in an elasto biological ent ent acceptable, generally cylindrical in shape, having a length substantially equal to that of the part of urethra concerned, holding means being provided to ensure the retention in place of said tubular element in the urethra and at least one passage being formed in the wall of said tubular element to ensure communication between the interior thereof and the urethra when said prosthesis is in place, characterized in that the tubular element consists of a tube, the initial external cross section of which is greater than the internal cross section of the urethra zone concerned and of which a longitu¬ dinal was removed by defining a longitudinal opening between two longitudinal edges, said tube having, when its two edges s longitudinal are brought together, an external section substantially equal to the internal section of the urethra zone concerned, the means for holding said tubular element in the urethra being at least partially formed by the wall of the tubular element itself, which elastically has a natural tendency to reopen on either side of the middle line of its longitudinal opening, said longitudinal opening, simultaneously ensuring a passage of communication between the inside the tube and urethra. In accordance with a first embodiment, the prosthesis according to the invention is a prosthesis for the entire length of the penile urethra, the tubular element of which is intended to have its upstream end, with reference to the direction of the urine flow, located under the striated urinary sphincter, the length of said tubular element being substantially equal to that existing between said striated sphincter 105 and the external orifice 102 of the urinary canal. Alternatively, it can also be provided that the prosthesis only concerns certain areas of the penile urethra, in particular the bulbar urethra, or the elbow of the anterior penile urethra.

According to a second embodiment, the prosthesis according to the invention is an intraprostatic prosthesis, the tubular element of which is intended to have its upstream end, with reference to the direction of the urine flow, located downstream of the smooth sphincter 104 and to have its downstream end situated upstream of the striated sphincter 105, the length of said tube being substantially equal to that existing between the two aforementioned sphincters.

The thickness of the wall of the tube and the width of the longitudinal cut of the tube in the free state are advantageously chosen to ensure a wide passage of the urine flow, taking into account the internal diameter of said tube after bringing the two longitudinal edges together. longitudinal cutting while allowing sufficient elasticity to maintain the tube in the urethra by the natural tendency to the separation of the longi¬ tudinal edges.

To eliminate any risk of injury to the patient, the longitudinal edges of the longitudinal opening of the tube can be rounded.

According to an interesting construction of the prosthesis according to the invention, the tube comprises, in particular an insert in its thickness, a memory frame, tending to favor the opening of said tube while it is in place in the urethra zone concerned. In a first variant, said frame is constituted by a set of open rings arranged, as an insert, in planes perpendicular to the mean line of the tube. In a second variant, said frame consists of a mesh disposed as an insert; provision may be made for the wires of said grid to be arranged so that the wires of one of the two families of wires of the mesh are in planes perpendicular to the mean line of the tube, the wires of the other family being parallel to said mean line and which may or may not include a shape memory.

If the two families of wires have a shape memory and if the initial mean line of the tube is not rectilinear, such an insert reinforcement allows both to deform the deformed tube towards its initial mean line which improves the maintenance in place of the prosthesis and to open the tube on either side of the final average line, which, in addition to improving the retention in place, promotes the increase in the cross section of the urinary tract.

The memory frame is advantageously constituted by means of a shape memory metal, such as an alloy steel suitably treated. Furthermore, a urethral prosthesis according to the invention may include complementary holding means ensuring cooperation between said tube and the internal wall of the urethra when the prosthesis is in place therein. Thus, openings can be made in the wall of the tube, each constituting a whistle notch, the mean plane of which is oblique to the axis of the tube in the region of the opening, the upstream edge of the notch forming a beak intended to cooperate with the internal wall opposite the urethra, when said prosthesis is put in place. The mean plane of a whistle notch constituting an opening can make with the axis of the tube, when said axis is rectilinear, an angle of between 30 and 60 ° approximately. Advantageously, a whistle notch defining an opening is defined between an upstream edge and a downstream edge each situated substantially in a plane, the planes of 'two edges forming an acute angle between them. Preferably, the planes of the two edges of a notch form between them an angle of between 10 and 40 ° approximately, when the axis of the tube is brought into a rectilinear position. Preferably, the distance 1. between the spout and the downstream edge of the corresponding opening, when measured according to a generatrix of the tube, the axis of the latter being rectilinear, is substantially equal to half the length of the whistle notch determining said opening. The distance between two successive whistle cuts made according to the generatrix of the tube is at least equal to 4 times the distance 1., so as not to weaken the tube too much. The aforementioned openings can be provided. along the back generator and / or along the side generators, the openings formed along the back generator are advantageously arranged in staggered rows relative to the openings along the lateral generators. Furthermore, ces.ouvertures are arranged between successive V-notches, a single opening being present between two V-notches. Naturally, no opening can be made in the presence of a frame or a frame member . To ensure good flexibility of the tube of a prosthesis according to the invention for the penile urethra, with a view to its good tolerance by the patient, V-shaped notches are advantageously formed along the longitudinal edges of said tube. For example, these V-shaped notches are formed in equilateral trian¬ gles of 3 to 5 mm on a side and are arranged regularly, every 15 to 25 mm.

In a manner known per se, the upstream end of the tube of a prosthesis according to the invention for penile urethra, is shaped according to a bevel on its zone intended to be in contact with the ventral wall of the urethra. The tube may also include along one of its generators a radiopaque line, as well as a retaining means penetrating into the patient's bladder.

In the case where the prosthesis is intended to be used for the penile urethra of an adult patient, the tube used advantageously has, in the free state, an internal diameter of the order of 10 to 12 mm, the distance between the two longitudinal edges of the longitudinal opening being of the order of 9 to 11 mm and the wall thickness being of the order of 1.8 to 2.2 mm. One can in particular use a cylindrical half-tube.

In the case where the prosthesis is an intraprostatic prosthesis intended to be applied in an adult patient, the tube used advantageously has, in the free state, an internal diameter of 16 to 18 mm, the distance between the two edges longitudinal of the longitudinal opening being of the order of 14 to 16 mm and the wall thickness being of the order of 1.8 to 2.2 mm. The fitting of such a prosthesis can be carried out without difficulty by implementing optical monitoring of a sufficiently fine cytoscope, for example of 5 mm in diameter (Charrière 15). Instead of providing openings formed by whistle notches in order to constitute complementary means for holding the prosthesis, it is possible to form on the external wall of the tube small scales, approximately 5 mm wide for example, by simple cutting the wall, in the thickness thereof, over a length of 5 to 10 mm; each scale can have a thickness of approximately 0.5 to 1 mm in its longitudinal central zone. These scales cooperate with the wall of the urethra because they slightly protrude with respect to the external face of the tube as soon as the two longitudinal edges of the longitudinal opening are brought towards each other. This arrangement can be envisaged both for prostheses intended for the penile urethra as for prostheses intended for the prostatic urethra.

According to an advantageous variant of the present invention, there is also proposed a urethral prosthesis capable of being used both for the intraprostatic urethra and for the penile urethra, a prosthesis whose placement in the urethra can be performed without the presence around the prosthesis of a rigid guide or catheter; this absence of rigid guide makes it possible to be able to introduce a prosthesis of larger external diameter and therefore to obtain subsequently for urinary flow, a larger section, with constant wall thickness. To do this, according to the invention, the prosthesis is provided along a generatrix of the tube constituting the prosthesis being put in place, with a guide sheath capable of being traversed from end to end by a guide wire. The guide sheath is formed by sheath sections arranged in staggered rows, one on one edge and the other on the other edge of the longitudinal opening of the tube, which constitutes the prosthesis.

The guide wire alternately passing through the sheath sections, on the two edges of the opening, then acts as a bolt and holds the two edges of the longitudinal opening of the prosthesis against each other during the entire positioning phase, this which avoids the use of a catheter. According to this technique, the guide wire has sufficient rigidity to remedy the flexibility of the element constituting the prosthesis during placement and it suffices, under these conditions, to push the prosthesis from the meatus into its final position. and then remove the guide wire, which has played its role of stiffener. According to the invention, use is advantageously made of a thin metal guide wire, in particular less than a millimeter in diameter. According to a first embodiment of this variant, it is provided that the guide sheath is blind, the closed side being on the side of the prosthesis, which is closest to the bladder 201. In this case, we put in places the guide wire on the prosthesis then a tubular pusher is threaded onto the guide wire, behind the prosthesis, and the prosthesis is pushed into the urethra from the meatus 102 by acting on the tubular pusher. When the prosthesis is in place, the pusher is removed and the guide wire is then removed.

In another embodiment of this variant, the guide sheath is not blind. In this case, the guide wire is put in place as far as the bladder 201 with a cytoscope and protrudes outside the meatus 102. The prosthesis is then threaded onto the guide wire, then it is threaded onto the same wire. guide, a tubular pusher, the pusher is pushed to bring the prosthesis in place, the introduction being effected by the meatus 102 of the penis, then the pusher and the guide wire are removed.

The prosthesis guide sheath according to the invention can be arranged on the tubular element constituting the prosthesis, either in the thickness of the wall, or on the external face of said wall.

The variant, which has just been described, can be used for the fitting of tubular elements which, before their introduction into the urethra, have a straight rectilinear line, but can also be used for the fitting in the urethra of prostheses which, before their placement in the urethra, have a non-rectilinear mean line, for example, a bent mean line, in particular in U, in-Λ- (omega) or in half f \ - . U-shaped tufces are used for prostheses intended for the posterior 108 or anterior 107 area of the penile urethra, these prostheses constituting a partial sheathing of the penile urethra in the areas of curvature. The prostheses in -A- or in half -S ^ - are intended to be placed in the prostatic urethra, the latter being especially usable for organisms with small prostate. In all cases, the flexibility of the wall of the prosthesis allows, when the prosthesis is positioned on its guide wire, thanks to its guide sheath, to have a substantially rectilinear shape with very small areas of curvature, which greatly facilitates the placement of the prosthesis, while the U-shaped or - -. of the prosthesis element, before its introduction, allows the prosthesis to be held in position by elastic return when the guide wire is removed. It can therefore be seen that, for these prostheses, the initial line of which is not rectilinear, the presence of the guide sheath and of the guide wire make it possible to dispense with any rigid peripheral guide for positioning. The present invention therefore relates to a prosthesis as defined above. characterized by the fact that the tube has an external surface defined by generating lines substantially parallel to its mean line and comprises, along at least one generating line of its positioning configuration, a guide sheath internally allowing the ent ent slide of a guide wire.

The prosthesis advantageously comprises a single guide sheath constituted by a plurality of sections staggered on the two edges of the longitudinal opening of the tube; said sections preferably have a length of between 3 and 7 mm.

The middle line of the tubular element, before introduction into the urethra, can be straight, or U-shaped, or A-shaped (omega), or half-J shaped. , the total length of said mean line corresponding to that of the urethra part where the prosthesis is to be positioned.

When the guide sheath is in relief relative to the wall of the tube that constitutes the prosthesis, said relief has a height, relative to the wall of the tube, of between 0.5 and 3 mm.

In the case where the prosthesis is formed from a tubular element and where the mean line of this tubular element is not straight, the guide sheath is advantageously placed along the shortest generatrix of the tube located in its con¬ cavity, or along the longest generatrix of the tube located on its convexity. To better understand the object of the present invention, we will describe below, purely by way of illustration and not limitation, several embodiments shown in the accompanying drawing. In this drawing: - Figure 1 schematically shows a complete urethra from the bladder to the meatus urinary;

- Figure 2 is an elevational view of a prosthesis according to the invention, shown as in position in a penile urethra; - Figure 3 is a sectional view along

III-III of Figure 2, the shape of the tube in the free state being shown in dotted lines;

- Figure 4 is a partial view along IV-IV of Figure 2; - Figure 5 is a partial view in per¬ spective of an alternative embodiment of the tube which constitutes a prosthesis. according to the invention;

- Figure 6 is a partial section on VI-VI of Figure 5; - Figure 7 shows, in elevation, a prosthesis according to the invention in a U-shape intended for the bulbar urethra;

- Figure 8 shows the prosthesis of Figure 7 after its installation; - Figure 9 shows a prosthesis having a representation in elevation identical to that of Figure 7, said prosthesis being placed in the elbow of the anterior penile urethra;

- Figure 10 shows in elevation an intraprostatic prosthesis in the form of - "i-, said prosthesis being constituted by a tube with open cross section;

- Figure 11 shows the prosthesis of Figure 10 after its installation; - Figure 12 shows a variant of intra-prostatic prosthesis intended for an organism with a small prostate, this prosthesis having the shape of a half ^ - and consisting of a tube with open cross section; - Figure 13 shows partially, in perspective and on a large scale, the tube constituting the prosthesis of Figure 9 in the open position, before its introduction into the urethra;

- Figure 14 shows the tube of Fig¬ ure 13 in the closed position through the introduction of the guide wire in the guide sheath.

In order to give meaning to qualifications such as "upstream", "downstream", "ventral" or "dorsal", it will be advisable to orient the urethral prosthesis relative to the urethra, into which it is intended to be introduced, referring to the direction of the urine flow. Under these conditions, the upstream part of the prosthesis is that closest to the striated sphincter 105 located under the bladder 201 and the ventral face of this prosthesis is that in contact with the ventral part, that is to say lower, th the inner wall of the urethra. The downstream part of the prosthesis is located at the end opposite to the upstream part. The dorsal side of the prosthesis is the side opposite the ventral side with respect to the midline of said prosthesis. As can be seen in Figure 2, the urethral prosthesis, which is shown, consists of a tube 1, flexible, in a biologically acceptable elastomer such as silicone rubber. The length of this tube is substantially equal to that existing between the striated urinary sphincter and the external orifice of the urinary canal: this length is generally between 15 and 25 cm. The wall 2 of this tube, in the free state, is of cylindrical shape, and has over its entire length, a longitudinal opening obtained by removal of a longitudinal strip. Are thus formed two longitudinal edges facing 4a, 4b (Figures 3 and 4).

The internal diameter of the tube 1 is, in the absence of constraint, about 11 mm and its thickness is 2 mm: such a tube is called "Charrière 33", according to the name used in urology. The distance D between the edges 4a and 4b is of the order of 10 mm in the middle of the thickness when these two edges are brought together, which corresponds to the position when the prosthesis is in place in the urethra, the internal diameter is of the order of 7 to 8 mm, which corresponds to a "Charrière 21-24" tube and to the cali¬ bre of a urethra.

This design represents a good compromise between finding the largest possible passage for the urine flow and, simultaneously, the greatest possible elasticity for the wall of the tube, so that the tub in place in the urethra has a strong tendency to reopen, to resume the diameter it had in the free state, ie when the two edges (Aa, 4b) are not forced towards each other.

When the tube 1 is in place in the urethra, the zone comprising the two edges 4a, 4b close together is arranged opposite the ventral wall of the urethra. Each of the two edges (4a and 4b) is rounded on the external side to avoid the pressing of a sharp edge on the urethra, as seen in fig¬ ure 3.

Notches 5 are made in the tube along the edges 4a_, 4b. These notches 5 are arranged, for example every 24 mm, this distance being measured between the bottoms of two successive notches. These indentations are each defined between two planes which intersect along an edge perpendicular to the mean line of the tube, these two planes being symmetrical with respect to a plane perpendicular to said mean line. The section of the notch by a plane perpendicular to said edge is an equilateral triangle with a side of 4 mm. These notches 5 give the prosthesis a great flexibility of flexion which avoids painful sensations in particular when the patient is in a sitting position. The outer edges of the notches 5 are rounded to avoid the support of a sharp edge on the urethra.

The upstream end of the tube 1 is open along a bevel 6 on its zone intended to be in contact with the ventral wall of the urethra. The bevel 6 is formed in two successive planes: the upstream area 6a of the bevel 6 is in a plane, which makes with the axis of the tube 1, when the latter is rectilinear, an angle of about 45 °; the downstream area 6b of the bevel 6, is a plane, which makes with the axis of the tube 1, when the latter is rectilinear, an angle 1j of approximately 10 ° and has a length d measured according to the ventral generatrix of the tube 1, the latter being rectilinear, substantially equal to 5 min. The total length of the bevel 6 is approximately 20 mm. This beveled opening 6 facilitates the positioning of the prosthesis in the urethra: the beveled end 6a of the tube 1 comes to flourish below the striated urinary sphincter; the bevelled area 6b comes into the area where the urethra forms an elbow, the angle of which is between 90 ° and 120 ° depending on the patient.

The distance between the free end of the bevelled part 6ci of the tube 1 and the bottom of the first notch 5 is of the order of 20 mm.

Furthermore, the wall 2 of the tube 1 comprises, in the example described, openings 7, which are ^' formed, all along this tube 1, on the tube zone located in the vicinity and along its lateral generatrices.

Each opening 7 constitutes a whistle notch, the mean plane of which is oblique with respect to the axis of the tube 1, in the zone of the opening, the upstream edge of the notch forming a beak 8: this is intended to cooperate with the wall opposite the urethra, when the tube enclosing the urethral prosthesis is in place to constitute a retainer for the prosthesis. 'Each spout 8 constitutes a bearing surface which, not being situated against the ventral internal wall of the urethra, does not cause any pain for the patient. Each whistle notch defining an opening 8 is delimited between an upstream edge and a downstream edge each located substantially in a plane; the planes of these two edges form an angle of about 25 ° between them, when the axis of the tube 1 is straight. The mean plane of a sif¬ flet cut constituting an opening 8 makes, with the axis of the tube 1, when the latter is rectilinear, an angle of approximately 45 °. The distance 1 between the spout 8 and the downstream edge of the corresponding opening 7, when measured according to the generatrix of the tube 1, is approximately 3 mm; the total length of the whistle notch determining the opening 8 is approximately 6 mm. The openings 7 are positioned in the middle zone between two successive notches 5; they are distributed on either side of the mean line of the prosthesis but are not necessarily made in all the intervals between two adjacent notches 5.

The tube 1 also includes, in the example described, in the vicinity and along its back generator, a plurality of openings 9- which are ^" identical to the openings 7 described above. These openings 9 are preferably arranged , in those of the intervals between two successive notches 5 where no openings 7 are made to avoid excessive weakening of the tube 1. However, certain intervals between two successive notches 5 may have no opening 7 or 9, as for example the one where the cut of figure 3 is practiced.

When the tube 1 is straight, it is say before introduction into a urethra, the nozzles 8 associated with the openings 7 and those associated with the openings 9 in no way protrude outside the wall 2. Once the tube is threaded into the urethra and the upstream end is abutted against the urinary sphincter, the beaks protrude from the wall 2 of the tube 1 due to the flexions due to the sinuosity of the urethra, and thus come into contact with the internal wall of the urethra: the large ones on - Support faces thus determined contribute to main¬ hold the prosthesis in place without discomfort for the patient, even for a relatively long time of the order of one to three months.

Furthermore, as shown in FIGS. 2, 3 and 4, it is possible to drown in the wall 2 of the tube 1 inserts constituted by split rings 10, arranged in planes perpendicular to the mean line of the prosthesis. These rings 10 facilitate the tendency of the tube 1 to return to its initial cylindrical shape, when the prosthesis is in place in the urethra. In the example described, one of these rings 10 is arranged in the vicinity of the downstream edge 6b of the beveled portion 6, between the latter and the first notch 5, and another ring 10 is disposed in the meantime between two notches 5 where no opening 7 or 9 is made: the presence of this second ring, shown in FIG. 2, in fact prevents the creation of such an opening 7 or 9. The rings 10 can be curved blades ring or wire; they are made of treated alloy steel which has shape memory. A plurality of rings 10 can be distributed over the entire length of the prosthesis.

In the variant shown in Figures 5 and 6, the prosthesis tube has been designated by 101 as a whole; the prosthesis, if it is intended at the penile urethra, may have the general shape previously described for the realization of Figures 2 to 4; on the other hand, if it is intraprostatic, the prosthesis has only the shape of a small section of cylinder. In the wall of the tube 101, there have been cut, in the thickness of the wall, scales 100, of rectangular shape; these scales are thin: they are about 0.5 mm thick in their central area and the thickness decreases towards the edges of the cut. The scales 100 can replace the whistle cuts 7.9 or be used simultaneously; in the absence of other complementary rete¬ naked means, provision may be made to produce a scale 100 every 20 mm approximately on the back generator of the tube and / or on its lateral faces, on either side of the passing plane by the dor¬ dirty and ventral generatrices of the tube 101. When the longi¬ tudinal edges of the longitudinal opening of the tube 101 are brought towards one another for the positioning of the prosthesis, the scales 100 protrude slightly relative to the wall of the tube and favor the retention of the prosthesis. Of course, each rectangular scale is defined by three cutting edges and an edge forming a hinge, the latter being arranged on the downstream side.

In all of FIGS. 7 to 14, the tubes constituting the prostheses according to the invention shown do not show any opening intended for the flow of urethral secretions. Nevertheless, it is explicitly stated that, in fact, the prostheses in question all have openings (not shown) passing through the wall of the tubular element which constitutes the prosthesis and, preferably, whistle openings of the type of those which are described in relation to Figures 2 to 6; the non-representation of said openings and their absence correlative description for the variants of fig¬ ures 7 to 14 has been made only for the purpose of simplification and clarity. The prostheses shown in the drawing may also include V-shaped notches of the type described for the production of FIG. 2, said notches being intended to give flexibility to the tube constituting the prosthesis in the areas where this is found. necessary for patient comfort. In FIG. 7, there is shown in elevation a prosthesis constituted by a tube 110 with an open circular cross section, the mean line of said tube having the shape of a U. The tube 110 has an internal diameter of 4 mm and an external diameter 7 mm; the longitudinal opening has a width of 14 mm. The longitudinal opening of the tube is made on either side of its shortest generatrix placed in the concavity of the U; on the longitu¬ dinaux edges of said longitudinal opening. This prosthesis comprises sections 111 of guide sheath each having a length of 0.3 mm and spaced from one another by intervals of 9 mm, said sections being arranged in staggered rows. Each of these sections constitutes a cylindrical tube having an outside diameter of 2 mm and an inside diameter of 1 mm. The set of sections 111 therefore constitutes a discontinuous guide sheath inside which a guide wire can be made to slide. The guide wire is a steel wire 0.7 mm in diameter; the tube 110 and the sections 111 are produced, in a conventional manner, in flexible silicone elastomer.

When the guide wire is threaded in the sections 111, the tube 110 is locked in the closed position, the edges of the longitudinal opening being one against the other; the mean line of the prosthesis also becomes substantially straight due to of the rigidity of the metal wire compared to the flexibility of the material constituting the tube 110. The prosthesis can then be introduced relatively easily by the meatus 102 using one or the other of the modes of positioning previously defined depending on the section of the upstream end of the prosthesis may or may not be blind. If we assume that this upstream end section is blind, we put on the guide wire, behind the prosthesis, a tubular pusher and l ^r we push the prosthesis into the urethra from the meatus 102 to the place as shown in Figure 8, This establishment is carried out so that the sections III are on the side of the dorsal part of the bulbar urethra. The sections 111 constitute means for ensuring that the prosthesis is held in place.

In FIG. 9, another urethral prosthesis according to the invention is shown, this other prosthesis corresponding to the same elevation view (FIG. 7) as the prosthesis of FIG. 8. The prosthesis of FIG. 9 is intended for the elbow of the anterior penile urethra 107. This prosthesis is constituted by a silicone elastomer tube, the middle line of which has a U shape; this tube 120 has an open cross section, the longitudinal opening of the tube being disposed on either side of its shortest generatrix, in the concavity of the U. The tube 120 has in the free state an internal diameter of 11 mm; the distance between the two longitudinal edges 120a, 120b of the longitudinal opening is 10 mm; the thickness of the wall is 1.5 mm. Along each of the edges 120a, 120b, sections of guide sheath 121a ^, 121b_ have been arranged respectively; the sections 12la ^ 121b have a length of 5 mm and they are staggered with respect to each other so that a section 12la comes to be positioned between two successive sections 121b when the edges ₁ 20-a and 120-b are brought together. ' When we compare the edges 120a and ₁ 20b, the tube 120 undergoes an outside diameter reduction and can be maintained in this state by threading into the guide sheath sections a guidewire 122. In addition to its lock function for main¬ hold the edges 120a and 120b against each other, the guide wire 122 has the same functions as the guide wire previously described for the prosthesis of FIG. 7: it also consists of a metallic wire of 0 , 7 mm in diameter; the sections 121a, 121b are cylindrical tubes with an internal diameter of 1 mm, which project about 0.5 mm from the outer wall of the tube 120. The guide wire 122 therefore serves to realign the two branches of the U that constitutes the tube 120, which greatly facilitates the introduction of the prosthesis into the urethra.

If it is assumed that the section of guide sheath, which is most upstream of the prosthesis, with reference to the direction of flow of the urinary flow, is a blind section, the fitting is carried out by threading the prosthesis by the urinary meatus and by pushing the prosthesis by means of a pusher 123, which is threaded on the guide wire 122 behind the prosthesis and which is supported on the section of guide sheath which is the most downstream. When the prosthesis has been put in place as shown in FIG. 9, the pusher is removed and then the guide wire 122. The removal of the guide wire 122 has two distinct effects: first, the tube 120 tends to open, as shown in Figure 13, by elastic return so that there is an expansion of the prosthesis inside the urethra when it is in place; secondly, the tube 120 tends to resume its U-shape, that is to say it tends to close the angle of the elbow of the anterior penile urethra, which is extremely favorable for its maintenance in position. In the form described and shown, the guide sheath sections 121a and 121b are located on the ventral, that is to say lower, face of the urethra.

The tendency of the prosthesis to return to its original shape, both with regard to its diameter and with regard to its midline, is essentially due to the elastic nature of its constituent material. However, it is possible to increase this elastic return by providing, inside the wall of the tube, a metal insert constituted for example by a mesh of 0.3 mm crisscrossed wires, said wires being wires. metallic with shape memory; the elastic return of the prosthesis can thus be reinforced when the guide wire 122 is removed.

In Figure 10, there is shown in elevation an intraprostatic prosthesis according to the invention. This prosthesis consists of a tube 130 of silicone polymer having an outside diameter of 7 mm, an inside diameter of k mm, a longitudinal opening 14 mm in width and having a medium line in the form of - '^ -. The full length of the tube 130 measured along its mean line is 50 to 80 mm. On the shortest generatrix of the tube, that is to say the one located in the concavity, we staggered on the edges 130a, 130b of the longitudinal opening, of the sections 131 of the guide sheath, sections which are identical in all points to the sections 111 previously described, except that they are 7 mm long and qu 'they are separated by 5 mm intervals. The sections 131 allow the introduction of a guide wire identical to the guide wire 122. The upstream section of the prosthesis is not blind. When the guide wire is placed in the sections 131, the mean line of the prosthesis becomes substantially rectilinear since the 130 is flexible enough to deform taking into account the rigidity of the guide wire threaded in the sections 131. The guide wire also serves as a lock for holding the edges 130a, 13Ob against one another during the positioning. For placement, the upstream end of the guide wire is introduced with a cytoscope into the bladder; then the tube 130 is threaded onto the guide wire and the tube 130 is pushed onto the guide wire by means of a tubular pusher identical to the pusher 123, said tubular pusher threading on the guide wire behind the prosthesis and resting on the section 131 located furthest downstream. The prosthesis is thus pushed into the urethra until it is placed in the position shown in FIG. 11: it can be seen that the upstream end of the prosthesis is behind the smooth sphincter 104, the downstream end being at the veru montanum 109 upstream of the striated sphincter 105. The pusher is then removed, then the guide wire. When the guide wire is extracted, the tube 130 tends to return to its shape in -A-, which ensures that it remains in place since the two ends are pushed onto the back generator of the urethra and are there maintained thanks in particular to the sections 131, which constitute attachment means; and simultaneously the edges 130a, 130b move away from each other which cooperates in maintaining the position of the prosthesis. Instead of planning to place the longitudinal opening of the tube 130 opposite the dorsal face of the urethra, provision may be made to place it opposite the ventral side: in this case, the longitudinal opening of the tube 130 and the sheath sections 131 are arranged in the vicinity of the longest generatrix of the tube, on the convexity; this provision makes it possible not to risk impeding the normal flow of the seminal fluid supplied by the ejaculatory ducts in the vicinity of the veru montanum, even if the prosthesis is not perfectly positioned. In FIG. 11, there is shown a vari¬ ante of intraprostatic prosthesis intended for organizations with a small prostate. In this variant, the prosthesis consists of a tube 140 with an open circular cross section, the tube comprising a discontinuous guide sheath formed of sections 141, which constitute a cylindrical channel having the same internal diameter as the guide sheath formed by the sections 131. In this embodiment, the sections 141 are formed in the thickness of the wall of the tube 5 140 and do not protrude from the outside face of this wall. This guide sheath 141 can be traversed right through by a metallic guide wire which makes it possible to make the tube 140 substantially rec¬ tilinear when it is placed in the urethra. 0 The tube 140 has the shape of a half - - _t, the two end portions being substantially parallel and being connected by an oblique branch whose mean line forms an angle of 70 ° with the mean lines of the two sections. end. - The establishment of this prosthesis is carried out in the same way as previously described for the prosthesis of ^" Figure 10 but the sections 141 do not cooperate in maintaining the position of the prosthesis; in compensation, the absence of relief ° increases user comfort.

Claims

1 - Prosthesis for the urinary tract consisting of a flexible tubular element made of a biologically acceptable elastomer, of generally cylindrical shape, having a length substantially equal to that of the part of the urethra concerned, holding means being provided to ensure the hand ¬ hold in place said tubular element in the urethra and at least one passage being made in the wall of said tubular element to ensure communication between the interior thereof and the urethra when said prosthesis is in place, characterized by the fact that the tubular element consists of a tube (l, 110, 120, 130, 140), the initial external cross section of which is greater than the internal cross section of the urethra zone concerned and of which a longitu¬ dinal was removed by defining a longitudinal opening between two longitudinal edges (4a, 4b; 12la, 121b) said tube having, when its two longitudinal edges are brought together s against each other, an external section substantially equal to the internal section of the urethra zone concerned, the means for holding said tubular element in the urethra being at least partially formed by the wall of the tubular element itself, which elastically has a natural tendency to reopen on either side of the middle line of its longitudinal opening.

2 - Prosthesis according to claim 1, characterized in that the longitudinal edges (4a, 4b) of the longitudinal opening of the tube (1) are rounded.

3 - Prosthesis according to one of claims 1 or 2, characterized in that the tube (1) com¬ carries, in particular in insert in its thickness, a memory frame (10), tending to favor the return of said tube (1 ) to its original shape, while it is in place in the urethra.

4 - Prosthesis according to claim 3, characterized in that the frame (10) consists of a set of open rings arranged in planes perpendicular to the middle line of the tube (1).

5 - Prosthesis according to claim 3, characterized in that the frame is constituted by a grid of interlaced wires with shape memory.

6 - Prosthesis according to one of claims 1 to 5, characterized in that it comprises complementary holding means (7,9, 100) other than the wall of the tube (1) itself ensuring cooperation between the tube (1) and the inner wall of the urethra, when the prosthesis is in place therein.

7 - Prosthesis according to claim 6 characterized in that openings (7,9) are formed in the wall (2) of the tube (1), each constituting a notch in the whistle, the mean plane of which is oblique to the axis of the tube in the area of the opening (7, 9), the upstream edges of the notch forming a beak (8) intended to cooperate with the internal wall facing the urethra, when said prosthesis is put in square.

8 - Prosthesis according to claim 7, characterized in that a whistle notch forming an opening (7,9) is defined between an upstream edge and a downstream edge each located substantially in one plane, the planes of the two edges forming between them an acute angle.

9 - Prosthesis according to one of claims 7 or 8, characterized in that the openings (7,9} formed along the back generator and / or along the lateral generators of the tube (1). 10 - Prosthesis according to claim 9, characterized in that the openings (9) formed along the back generator are staggered relative to the openings (7) formed along the lateral generators.

11 - Prosthesis according to one of claims 6 to 10, characterized in that V-shaped notches (5) are formed along the longitudi¬ nal edges (4a, 4b) of the longitudinal opening of the tube (1).

12 - Prosthesis according to claim 11, characterized in that the V-shaped notches (5) are formed according to equilateral triangles of 35 mm side and are arranged regularly, every 15 to 25 mm.

13 - Prosthesis according to one of claims

I to 12, intended to be placed in the penile urethra of an adult patient, characterized in that the tube (1, 110, 120) used in a cross section delimited by two concentric circles and presents, at l free state, an internal diameter of 10 to 12 mm, the distance between the two longitudinal edges (4a, 4b; 12lai, 121b) of the longitudinal opening being 9 to

II mm and its wall thickness being 1.8 to 2.2 mm. 14 - Prosthesis according to one of claims

1 to 12, intended to be placed in the prostatic urethra of an adult patient, characterized in that the tube (130, 140) used has a cross section delimited by two concentric circles and present, in the state free, an internal diameter of 16 to 18 mm, the distance between these two free longi¬ tudinal edges being 14 to 16 mm and its wall thickness being 1.8 to 2.2 mm, the length of said tube being slightly less to that existing between the smooth sphincter and the striated sphincter.

15 - Prosthesis according to one of claims l to 14, characterized in that the tube (-110,

120, 130, 140) has an external surface defined by generating lines substantially parallel to its mean line and comprises, along at least one generating line, a guide sheath internally allowing the sliding of a guide wire (122 ).

16 - Prosthesis according to claim 15, characterized in that the guide sheath (111,

121, 131) constitutes, on the outside of the tube, a relief which has a height, with respect to the face of the wall of the tube to which it is connected, of between 0.5 and 3 mm. _-

17 - Prosthesis according to claim 15, characterized in that the guide sheath (141) is arranged between the external face and the internal face of the wall of the tube 140.

18 - Prosthesis according to one of claims 15 to 17, characterized in that the guide sheath (111, 121, 131, 141) is discontinuous and consists of sections spaced from each other by an interval and arranged in staggered rows on the two longitudinal edges of the longitudinal opening of the tube (110, 120, 130, 140), the sections of one edge having a length less than the interval between two sections of the other edge.

19 - Prosthesis according to claim 18, characterized in that the sections of guide sheath and the intervals which separate them have lengths between 3 and 7 mm. 20 - Prosthesis according to one of claims

15 to 19, characterized in that the mean line of the tubular element in the free state is rectilinear or slightly bent at its two ends, in particular for a prosthesis intended for the whole of the penile urethra, or even in form of _. U, in particular for a prosthesis intended for the bulbar urethra or the elbow of the anterior penile urethra, or even in the form of - - or half \ -, in particular for a prosthesis intended for the prostatic urethra, the total length of said average line corresponding to that of the part of urethra where the prosthesis must be positioned.