阅读说明：本技术 人造可收缩结构及包括这种人造可收缩结构的医疗装置 (Artificial collapsible structure and medical device comprising such an artificial collapsible structure ) 是由 克里斯多夫·奥贝特 费比安·卡奇 弗朗索瓦·卡保德 于 2017-11-30 设计创作，主要内容包括：本发明涉及一种人造可收缩装置,该人造可收缩装置包括至少一个可收缩元件(1),该可收缩元件包括沿纵向方向延伸的柔性条带(4)和闭合件(6),该闭合件用于将可收缩元件(1)形成为围绕中空人体器官的闭合环,闭合件(6)位于柔性条带(4)的第一末端处。可收缩元件适于收缩中空人体器官,使得所述可收缩元件(1)可以处于静止位置或处于激活位置。人造可收缩装置进一步包括柔性传动装置(3),该柔性传动装置包括张紧元件(31),该张紧元件在第一端部(311)处被锚固到柔性条带(4)上的第一锚固点(A),当通过致动器(7)在张紧元件(2031)的端部处施加牵引力时,所述柔性传动装置(3)适于收紧可收缩元件(1),该可收缩元件围绕所述中空人体器官形成为闭合环。人造可收缩装置还包括连接器(5),该连接器适于将柔性传动装置(3)连接到所述致动器(7),所述张紧元件(2031)的第二端部(312)被锚固在所述连接器(5)中。(The invention relates to an artificial contractile device comprising at least one contractile element (1) comprising a flexible strip (4) extending in a longitudinal direction and a closure (6) for forming the contractile element (1) into a closed loop around a hollow human organ, the closure (6) being located at a first end of the flexible strip (4). The contractile element is adapted to contract a hollow human organ, such that said contractile element (1) can be in a resting position or in an activated position. The artificial contractile device further comprises a flexible transmission (3) comprising a tensioning element (31) anchored at a first end (311) to a first anchoring point (a) on the flexible strap (4), said flexible transmission (3) being adapted to tighten the contractile element (1) formed as a closed loop around said hollow human organ when traction is applied at the end of the tensioning element (2031) by an actuator (7). The artificial retractable device further comprises a connector (5) adapted to connect a flexible transmission (3) to the actuator (7), the second end (312) of the tensioning element (2031) being anchored in the connector (5).)

1. An artificial collapsible structure, the artificial collapsible structure comprising:

-at least one contractile element (1) comprising a flexible strip (4) extending in a longitudinal direction and a closure (6) for forming the contractile element (1) into a closed loop around a hollow human organ, the closure (6) being located at a first end of the flexible strip (4), the contractile element being adapted to contract the hollow human organ such that the contractile element (1) is adapted to be in a resting position or in an activated position, the activated position being defined by the contractile element (1) contracting the hollow human organ and the resting position being defined by the contractile element (1) not contracting the hollow human organ,

characterized in that the artificial collapsible structure further comprises:

-a flexible transmission (3) comprising a tensioning element (31) anchored at a first end (311) to a first anchoring point (a) on the flexible strip (4), the flexible transmission (3) being adapted to tighten the contractible element (1) which forms a closed loop around the hollow human organ when a traction force is applied at the end of the tensioning element (31) by an actuator (7), and

-a connector (5) adapted to connect the flexible transmission (3) to the actuator (7), the second end (312) of the tensioning element (31) being anchored in the connector (5).

2. An artificial collapsible structure according to claim 1 characterised in that the tensioning element (31) is covered with a flexible sheath (32).

3. An artificial collapsible structure according to claim 1 or 2, characterised in that the flexible strip (4) comprises a plurality of transverse stiffening elements (42) extending from the surface of the flexible strip opposite the smooth surface arranged to contact the hollow human organ.

4. An artificial collapsible structure according to claim 3 characterised in that the flexible strip (4) comprises a plurality of openings (43), each opening being located between two adjacent transverse stiffening elements (42).

5. An artificial collapsible structure according to the preceding claim characterized in that the tensioning elements (31) are filaments, wires, cables or flat strips.

6. Artificial collapsible structure according to any one of claims 3-5, characterized in that the tensioning elements (31) pass through at least some of the transverse reinforcing elements (42).

7. Artificial collapsible structure according to one of claims 2 to 6 characterized in that the sheath (32) comprises at least one coiled wire (18a, 18 b).

8. An artificial contractile structure according to claim 7, characterized in that the sheath (32) comprises an inner coiled wire (18a) coiled in a first direction and an outer coiled wire (18b) surrounding the inner coiled wire (18a) and coiled in a second direction opposite to the first direction.

9. An artificial collapsible structure according to the preceding claim characterised in that the closure (6) is arranged to form the collapsible element (1) as a closed loop having one of a plurality of predetermined circumferences.

10. An artificial collapsible structure according to claim 9 wherein the closure (6) comprises a tab (61) located at the end of the flexible strip (4) and connected thereto by two connecting side walls (62) integrally formed with the tab (61) and the flexible strip (4) to define a through hole (63) for passing the flexible transmission means (3) and the connector (5) forming the collapsible element (1) as a closed loop around a hollow body organ.

11. An artificial collapsible structure according to the preceding claim characterised in that the connector (5) is configured to be push-fit connectable to an actuator (7).

12. An artificial collapsible structure according to claim 11 wherein the push-fit connector (5) comprises a helical spring (71) or an O-ring coupling a first annular groove (71 g; 52d) provided in one of the actuator (7) and the connector (5) and providing a kinematic coupling with a further annular groove (52 d; 71g) provided in the other of the actuator (7) and the connector (5).

13. An artificial collapsible structure according to one of claims 11-12 wherein the connector (5) comprises a link (52) longitudinally movable within a coaxial plunger (51), the link being attached to the tensioning element (31).

14. An artificial collapsible structure according to claim 13 wherein the link (52) comprises a serrated portion (52a) which cooperates with a releasable hook member of the plunger (51) to enable movement of the link (52) in the plunger.

15. Medical device comprising an artificial retractable device according to any of claims 1-13 and an actuator (7) comprising a connection socket (7c) configured for a push-fit connection with the connector (5), the actuator (7) comprising an actuation mechanism (7b) arranged to apply a tension to the tensioning element (31) of the flexible transmission (3) when the connector (5) is connected into the socket (7 c).

Technical Field

The present invention relates to the field of implantable medical devices, in particular to the field of medical devices comprising an artificial collapsible structure for occluding hollow human organs.

Background

For the treatment of diseases such as urinary incontinence, fecal incontinence, gastroesophageal reflux disease, and for the treatment of obesity by gastric banding, a medical device is typically implanted in the patient, which includes an artificial collapsible structure, commonly referred to as a cuff, attached around a hollow body organ such as the urethra, rectum, esophagus or stomach. In order to reduce the diameter of the organ in question or to occlude the organ, the artificial contractile structure applies pressure to the organ. In particular in the case of urinary or fecal incontinence, the collapsible structure essentially forms an artificial sphincter that can be opened and closed by controlling the pressure exerted by the cuff.

In such applications, it is important to apply the pressure as lightly as possible in order to avoid damage to the organ. Currently, this is usually achieved by inflating a tube or balloon type structure arranged inside the contractile element and applying pressure to the organ. An example of a commercially successful device of this type is AUS 800 sold by American Medical Systems, inc. The device and its precursors are described in US 3,863,622, US 4,222,377, US 4,412,530 and US 4,878,889. When used in the treatment of urinary incontinence, the device has a silicone pressure regulating balloon implanted in the side bladder fossa, a silicone control pump implanted in the scrotum or labia, and a silicone urethral occlusive cuff wrapped around the male bulbar urethra or female bladder neck. Each component may be filled with saline or radiopaque contrast media, and tubing leading from each component may be routed between the incisions to make the appropriate connections. The patient operates the device by squeezing the control pump through the scrotal or labial skin and this action transfers fluid from the cuff to the pressure regulating balloon to release pressure to the urethra and allow urination, after which the balloon forces the fluid through the flow restrictor and back into the collapsible member to reestablish the occluded urethra pressure in 3 to 5 minutes. In addition, the device may be deactivated prior to insertion of a catheter or other instrument into the urethra to initiate healing of the tissue and to cause resolution of the urethral edema.

However, implantation of this type of device is extremely complicated because it requires assembling and filling the three interoperative parts with fluid in situ, and when inflated, the device may fold or change its shape in an uneven manner, thereby creating a so-called "pillow" which may cause uneven pressure to be applied. In addition, these three interoperative components are prone to fluid leakage and may cause atrophy and erosion of the urethra. Fluid leakage may also lead to complications, such as post-operative infection, requiring maintenance or replacement of the device.

Various attempts have been made in the past to design non-hydraulic cuffs that are not limited to the above. For example, US 6,074,341 describes a medical device comprising a non-hydraulic cuff that is spring biased in an occlusive position. The tension applied to the wire member by the actuator counteracts the spring bias, thereby opening the cuff. Upon release of the tension, the spring bias returns the ferrule to its occluded position. This arrangement raises safety concerns because in the event of actuator failure, the patient will not be able to urinate, requiring immediate emergency surgery to prevent kidney damage. US 2012/0184980 describes a medical device comprising different non-hydraulic cuff structures, wherein the cuffs are formed as sheaths arranged around the urethra and wherein a tape arranged inside the sheath is attached to an actuator and pulled in order to tighten the cuffs and apply an occlusive pressure to the urethra. However, the ferrule is complex and cumbersome. Still further examples include: US2012/0296157, which describes a medical device comprising an extremely simple wire-actuated cuff; WO13093074, which describes soft rubber cuffs actuated by wires; and EP 1547549, which describes a cuff that is tightened by twisting together a pair of wires located inside the cuff. Any of the latter three examples does not appear to achieve a gentle, uniform application of pressure to the organ.

It is therefore an object of the present invention to at least partly overcome some of the above-mentioned disadvantages of the prior art.

Disclosure of Invention

The object of the invention is achieved by an artificial contractile structure comprising at least one contractile element comprising a flexible strip extending in a longitudinal direction and a closure for forming the contractile element into a closed loop around a hollow human organ, the closure being located at a first end of the flexible strip, the contractile element being adapted to contract the hollow human organ such that said contractile element is adapted to be in a resting position or in an activated position, the activated position being defined by said contractile element contracting the hollow human organ and the resting position being defined by said contractile element not contracting the hollow human organ.

According to the invention, the artificial retractable device further comprises:

-a flexible transmission comprising a tensioning element anchored at a first end to a first anchoring point on the flexible strip, said flexible transmission being adapted to tighten a contractible element that forms a closed loop around said hollow body organ when a traction force is applied at the end of the tensioning element by an actuator, and

-a connector adapted to connect a flexible transmission to the actuator, the second end of the tensioning element being anchored in the connector.

As a result, the medical device applies gentle, uniform pressure to the hollow body organ without local pressure spikes, thereby reducing the effect of the medical device on the underlying tissue to reduce damage to the underlying tissue.

Furthermore, the device of the invention is extremely easy to implant in the patient and safely disconnected from the actuator, thanks to the provision of a plug-and-play type connector, advantageously of push-fit type.

In an embodiment, the tensioning element is covered with a flexible sheath.

In an embodiment, the flexible strip comprises a plurality of transverse reinforcing elements extending from a surface of the flexible strip opposite to the smooth surface arranged to contact said hollow human organ.

In an embodiment, the flexible strip comprises a plurality of openings, each opening being located between two adjacent transverse stiffening elements.

In an embodiment, the tensioning element is a filament, a wire, a cable or a flat strip.

In an embodiment, the tensioning element passes through at least some of the transverse reinforcing elements.

In an embodiment, the sheath comprises at least one coiled wire.

In an embodiment, the sheath comprises an inner coiled wire coiled in a first direction and an outer coiled wire surrounding the inner coiled wire and coiled in a second direction opposite to said first direction.

In an embodiment, the closure is arranged to form the collapsible element as a closed loop having one of a plurality of predetermined circumferences.

In an embodiment, the closure member comprises a tab located at an end of the flexible strip and connected thereto by two connecting side walls, the two continuous side walls being integrally formed with the tab and the flexible strip to define a through hole for passing the flexible transmission and the connector, thereby forming the collapsible element as a closed loop around the hollow body organ.

In an embodiment, the connector is configured to be push-fit connected to the actuator.

In an embodiment, the push-fit connector comprises a helical spring or an O-ring coupling a first annular groove provided in one of the actuator and the connector and providing a kinematic coupling with a further annular groove provided in the other of the actuator and the connector.

In an embodiment, the connector comprises a link longitudinally movable within the coaxial plunger, said link being attached to said tensioning element (31).

In an embodiment, the link comprises a toothed portion which cooperates with a releasable hook member of said plunger to enable the link to move in said plunger.

The object of the invention is also achieved by a medical device comprising an artificial contractile structure as described above and an actuator comprising a connection socket configured for a push-fit connection with said connector, said actuator comprising an actuation mechanism arranged to apply a tension to said tensioning element of the flexible gearing when said connector is connected into said socket.

Drawings

The invention will now be further described with reference to the accompanying drawings, which show:

fig. 1A and 1B: a perspective view of an artificial collapsible device according to the invention having an open collapsible element assembled with its tensioning device and connector;

-figure 2: a perspective close-up view of the closed end of the collapsible element of the artificial collapsible device of this invention;

-figure 3: a longitudinal cross-sectional view of a collapsible element of an artificial collapsible device of the present invention;

-figure 4: a longitudinal cross-sectional view of a connector of an artificial retractable device of the invention;

-figure 5: a longitudinal cross-sectional view of a connector of an artificial retractable device of the invention connected to a screw-type actuator;

-figure 6: a perspective view of a cross section of a wire coil element of a jacket for a tensioner of an artificial retractable device of the present invention.

Detailed Description

Fig. 1A and 1B show a part of an artificial contractile device according to the invention, in particular a contractile element 1 (also called a cuff) assembled with a tensioning device 2. In the view of fig. 1, a collapsible element 1 is shown in its open position, i.e. its position before being applied around a hollow body organ. The shrinkable element 1 comprises a flexible strip or ribbon 4 extending in a longitudinal direction, for example constituted by an implant-grade silicone elastomer having a shore hardness sufficient (for example between 40 shore a and 80 shore a, preferably between 50 shore a and 43 shore a). As non-limiting examples, liquid silicone elastomers from Nusil corporation, such as MED-4843 with a Shore A hardness of 43, MED-4860 with a Shore A hardness of 60, or MED-4850 with a Shore A hardness of 50, may be used. Alternatively, polyurethane or other flexible, biocompatible thermoplastic materials may be used instead of or in addition to silicone elastomers.

A plurality of transverse stiffening elements 42, in this example evenly spaced and numbered, but the number and spacing can be chosen according to the needs of the person skilled in the art, is arranged along the flexible strip 4. The transverse reinforcing elements 42 are aligned substantially perpendicular to the above-mentioned longitudinal direction and exhibit a substantially curved shape, but other forms are also possible. Advantageously, the openings 4343 are provided between pairs of adjacent transverse reinforcing elements 42. In this example, these openings 43 are formed as slots between some of the transverse stiffening elements 42.4343. These openings 43, which have a substantially rectangular form, are arranged on the centre line of the shrinkable element 1 and extend towards the edges of the shrinkable element. Of course, other forms of openings 43 are possible. The openings 43 serve to reduce the tension required to apply force to the hollow body organ, since less shrinkable element material needs to be compressed when activating the shrinkable element 1.

At the distal end of the flexible strip 4 a closure member 6 is provided, which is shown in more detail in fig. 2 and 3. Said closure 6 comprises a tab 61 extending at the free end of the flexible strip 4 and connected thereto by two connecting side walls 62 integrally formed with the end flap 41 of the strip 4 and with the tab 61. The tab 61, the wall 62 and the flap 41 define a through hole 63. Thus, by winding the flexible strip 4 around said hollow body organ and passing the opposite free end of the artificial contractile device, including the connector 5, through the through hole 63 to tighten the contractile element 1 to its desired diameter, the closure member 6 can be arranged to enable the contractile element 1 to form a closed, substantially circular cuff around the hollow body organ.

Advantageously, tab 61 comprises, on the inner surface facing flap 41, a slot 64 adapted to cooperate in a snap-fit manner with reinforcing element 42 on flexible strip 4, so as to lock the strip in position with the desired contracted diameter when wound around a hollow body organ.

When the collapsible element 1 is in place around a hollow body organ in its closed position, its maximum circumference may for example be 6cm for implantation around the male urethra or may for example be 11cm for implantation around the female bladder neck. However, other minimum and maximum perimeters are of course possible. By way of example, the width of the flexible strip 4 may be between 7mm and 10mm, but naturally larger widths and smaller widths are also possible. As previously mentioned, the closure 6 is arranged to close at a plurality of discrete closure positions, or alternatively, the closure 6 may be arranged such that it can close at any convenient point on the flexible strip 4.

The artificial contractile device of the invention further comprises a tensioning device 2 comprising a flexible transmission 3 extending between said contractile element 1 and said connector 5 to apply tension to the contractile element 1 by means of an actuator attached with the connector 5.

The flexible transmission 3 comprises a core of wire 31 surrounded by a sheath. The sheath comprises an outer sheath 32, for example made of silicone elastomer, which covers the wire coil 18 (fig. 6), the wire coil 18 covering the wire 31, the wire 31 substantially following the configuration of a Bowden cable. As a result, pulling or pushing the wire 31 will cause the wire 31 to move relative to the sheath. The wire 31 may be made, for example, of stainless steel or other metal alloys (e.g., SS 304V, 316L, MP35N, MP35NLT) and may be housed in an ePTFE or PTFE tube or coated with an ePTFE or PTFE coating to reduce friction. Furthermore, the number and diameter of the strand wires comprising the wire 31 should be chosen such that friction is minimized and the wires can also be re-drawn to smooth the surface of the wires and coated with PTFE or similar lubricant material. Alternatively, the wires 31 may be made of titanium, nitinol or any other suitable biocompatible metal, or of a polymer such as PTFE, aramid, ultra high molecular weight polyethylene (e.g., sold by Dyneema), or the like. The cross-section of the wire 31 may also be flat or oval or even variable (e.g. circular in the wire coil 18 and flat in the collapsible element 1). Alternatively, a cable with a circular or flat cross-section may be used instead of a wire.

The outer sheath 32 includes a thicker proximal portion 32a (relative to the connector 5) that covers the flexible drive means 3 from the connector 5 to the stiffer proximal end of the flexible strip 4 (relative to the connector 5) that connects the flexible strip to the flexible drive means 3, and a thinner more flexible distal portion 32b (relative to the connector 5) that extends up to the closure 6 as described below. The proximal and distal portions 32a, 32b are attached to the collapsible element 1 by push-fitting the proximal and distal portions 32a, 32b into the openings 43 between the reinforcing elements 42. The wire 31 protrudes from the outer sheath 32 and the wire coil 18 at a distal first end at which an anchoring knot 311 is formed, this knot 311 fitting firmly into the anchoring slot 44 of the flexible strip 4 close to the closure member 6. The knot 311 may be glued into the corresponding anchoring slot 44 or preferably associated with the first retaining plate 45, thereby forming a first anchoring point a. The sheath 16 is further secured at a second anchor point B located at the interface between the proximal and distal portions 32a, 32B of the sheath 32. Said second anchoring point B may be formed by a second retaining plate accommodated in a second anchoring slot arranged in the reinforcing element 42. The second retention plate and the second anchor slot are not shown in the figures. The first and second retention plates may be made of a metallic biocompatible material that is welded to the wire loop 18, and the wire 20 remains free to slide through the wire loop 18, as described below.

Still preferably, after positioning the sheath 32, the outer sheath 32 is completely fixed to the flexible strip 4 by gluing or overmoulding it in the constituent material of the strip 4, as described above, which further allows the formation of a reinforcing end cap 46 for the strip 4 from which the proximal portion 32a of the sheath 32 extends further above the wire coil 18 up to the connector 5, as described below.

The opposite end of the tensioner 2, including the connector 5 shown in figure 4, is arranged to be attached by this connector 5 to a suitable actuator 7, partially visible in figure 5, described for example in WO13091730, WO13093074 or WO12000681, which are all incorporated herein by reference. The force applied by the actuator 7 to the wire 31 via the connector 5 causes the wire 31 to slide within the wire coil 18 of the flexible transmission 3, thereby causing the flexible strip 4 of the retractable element 1 to longitudinally contract, which enables a contraction action on the hollow body organ when said retractable element 1 is encircling said hollow body organ.

Fig. 4 and 5 show a push-fit connector 5 for attaching the flexible transmission 3 including the wire 313 of the tensioning device 2 to the actuator 7.

The illustrated actuator 7 comprises a housing 7a inside of which a screw-type mechanism 7b is mounted. Naturally, other types of mechanisms 7b are possible.

In order to simplify the in-situ assembly of the entire system (i.e. assembly within the patient's body cavity), the attachment of the connector 5 to the actuator 7 is performed by a push-fit joint, which will be explained in more detail below.

As shown in fig. 4 and 5, the second end of the wire 31 (i.e. the end opposite to the end forming the knot 311 held in the anchoring slot 44 of the strap 4) also comprises an anchoring knot 312 fixed to the plunger 51. Plunger 51 comprises a substantially cylindrical body 51a extending longitudinally inside the cavity of protective casing 34, preferably made of the same biocompatible flexible material as sheath 32 and flexible strip 4, in particular for example of silicon-based material, which can be overmoulded on plunger 51 and integral with sheath 32 or glued to sheath 32. The protective shell 34 may be retained on the plunger 51 by inserting material into a recess (not shown) disposed on the outer surface of the plunger body 51 a. The plunger head 51b extends outwardly from the body 51a to the exterior of the protective shell 34. The plunger 51 has an open internal channel or tube 51c extending the entire length of the plunger, in which a link 52 is fitted, said link comprising a serrated portion 52a housed in the body 51a of the plunger and a connecting head 52b extending through the plunger head 51 b. The wire 31 passes in a lumen or capillary in the linkage 52 and the knot 312 of the wire 31 is received in the end recess 52c in the connecting head 52 b. Thus, the wire 31 is fastened to a link 52 which mechanically couples the transmission 3 to the actuator 7, as will be described hereinafter.

Advantageously, the link 52 is translatable within the plunger 51 to enable the tensile strength exerted by the actuator 7 on the link 52 to contract or release the wire 31 in the flexible transmission 3, thereby contracting or releasing the contractible element 11. However, this displacement capability may be limited by the toothed configuration of the indented portion which, upon application of pressure as indicated by arrow F in figure 5, engages with the inner hook member which extends radially inwardly from the body 51a of the plunger. Activation of the hook-shaped members enables the linkage rod 52 to be locked in place, enabling manual disconnection of the connector 5 from the actuator 7 without over-constricting the retractable element around the urethra. This locking mechanism of the link 52 enables any pulling/pushing action on the connector 5 to be transmitted only to the plunger 51 and not to the wire 31 in the flexible transmission, thereby allowing safe connection and disconnection of the actuator for the contracted organ.

The head 51b of the plunger 51 is cylindrical and is a sliding fit within a tube socket 7c which extends from the housing of the control system. Upon insertion of plunger head 51b into socket 7c, connecting head 52b is attached to distal tip 7d of screw actuator 7b by any convenient attachment means. In the illustrated embodiment, the first coil spring 71 is held within a corresponding first annular groove 71g in the distal tip 7d of the screw actuator 7b, the first coil spring 71 fitting in a corresponding groove 52d, the groove 52d being disposed on the outer surface of the connecting head 52 b. Alternatively, an O-ring may be used instead of the coil spring. Upon insertion of the connection head 52b into the distal tip 7d of the screw actuator 7b, the coil spring 71 clamps into the annular groove 52d to retain the connection head 52b and plunger 51 on the distal tip of the screw actuator 7 and to transmit forces and movements thereto. In this sense, the annular spring provides a kinematic coupling between the distal tip of the actuator 7 and the link 52. As a variant, the position of the two annular grooves 71g, 52d can be reversed, if desired, so as to support the coil spring 71 in the connecting head 52b and to clamp into a groove in the distal tip 7d of the actuator 7.

In order to support the outer sheath 32 of the flexible transmission 3, the distal end of the protective shell 31 of the connector forms a hollow end cap which is fixed on the outside of the sheath 32 by means of a further annular spring 54, one end of which is arranged between the wire 31 and the sheath 32, and a seat 55, which seat 55 is arranged between the distal end of the serrated portion 52a of the link 52 and the distal end of the cavity 51 c. The wire 31 passes through an axial passage in the seat 55. The seat 55 is preferably made of a polymer with low friction and a smaller lumen diameter than the annular spring it guides to prevent the wire 31 from wearing. This is particularly advantageous because the annular spring 54 may have sharp edges. The seat 55 is also designed to be press-fitted into 51a or screwed into 51a to resist the thrust forces generated when connecting the head 52d of the plunger into the screw-type actuator 7 b.

To minimize fluid ingress between the connector 5 and the receptacle tube 7c and to hold the plunger 51 securely into the receptacle 7c, one or more coil springs 72 and one or more sealing rings 76 are provided in corresponding grooves in the inner wall of the receptacle tube 7c (one wire coil spring or one sealing ring is provided in each corresponding groove herein), the inner wall of the receptacle tube 7c being in contact with the outer portion of the plunger head 51 b.

Fig. 6 shows an embodiment of a wire loop 18 formed by a double wire loop 18a, 18b surrounding a wire 31. As can be clearly seen in this figure, the inner wire coil 18a is wound around the wire 31 in a first direction and the outer wire coil 18b, which surrounds the inner wire coil 18a, is wound in a second direction opposite to the first direction. This double coil arrangement helps to prevent kinking of the drive section of the tensioner 2 and helps to reduce the risk of breakage. This double coil arrangement also prevents the coils from crushing against each other when the actuator is bent. The outer wire coil 18b and optionally the inner wire coil 18a may be attached at a first end to the anchor plate 45 and at a second end formed as or attached to a loop spring 54 in a seat 55 of the connector 5.

Furthermore, as a simpler alternative, the wire coil 18 may be formed as a single coil, or further alternatively, a multilayer coil comprising more than two coils may be used.

An alternative arrangement (not shown) of the tensioning device 2 comprises a pair of wires 31 arranged to operate in opposite directions, so that pulling a first wire tightens the shrinkable element 1, while pulling a second wire loosens the shrinkable element 1.

In contrast to the above-cited prior art cuffs, the shrinkable element 1 is not only tightened by reducing its circumference in the manner of a slipknot, or by twisting the wires together. When tension is applied by the tensioning device 2, the second anchoring point B is pulled towards the first anchoring point a, thereby tightening the wire 31 down on the flexible strip 4. This causes the collapsible element 1 to bend, the transverse reinforcing element 42 resisting such bending and gently bending the collapsible element 1 in its cross-section into a U-shape or a U-like shape, instead of the sharp V-shape the collapsible element 1 assumes in cross-section in the absence of the transverse reinforcing element. As a result, gentle pressure is applied to the hollow body organ over as large an area as possible, thereby reducing tissue damage.

As a result, the shrinkable element 1 does not press against the underlying tissue and exerts a pressure of at most 8N/cm2, preferably at most 5N/cm2, further preferably at most 2N/cm 2. Furthermore, due to the way the flexible strip 4 is deformed for applying a pressure, this pressure around the circumference of the flexible strip is particularly uniform and varies along the flexible strip 4 by at most 15%, preferably at most 10%, preferably at most 5%, which is in contact with the hollow body organ when the collapsible element 1 is activated.

Fig. 1A to 1B show a retractable element 1 assembled with a tensioning device 2, the flexible transmission 3 of which is attached to a connector 5, ready for implantation. In use, the artificial contractile device of the present invention can be implanted in a patient by laparoscopic surgery, the contractile element 1, the tensioning device 2 of the contractile element and the connector 5 being manipulated by a trocar. The collapsible element 1 is formed into a loop around a hollow body organ, such as the urethra, by inserting the connector 5 into the through hole 63 of the occluding member 6 and pulling said connector until the proximal portion 32a of the outer sheath on the flexible strip enters said occluding member 6. This proximal portion 32a advantageously corresponds to a setting section for adjusting the diameter of the contractile element around the urethra when tension is applied to the wire 31 by the actuator, and also to a setting section of the so-called dead zone (i.e. the region of almost no contraction) of the contractile element 1. In order to set the diameter of the shrinkable element 1, it is only necessary to press the tab 61 to the desired position on the proximal portion 32a in order to insert the stiffening element 42 into the locking slot 62 of the closure tab 61. This can be easily accomplished with a trocar.

To facilitate handling and maintaining hygiene during this operation, the connector may advantageously be equipped with a screw-down cap 56 having a tapered, corrugated end to facilitate insertion into the closure member 6 and pulling with a trocar. When the diameter of the retractable element 1 is set around a hollow body organ, the surgeon pulls the connector 5 and transmission to the subcutaneous connection site where the actuator 7 is implanted, then manually unscrews the screw-down cap 56 and connects the connector 5 to the actuator 7 by a push-fit, as previously described.

A suitable actuator 7 (see fig. 5) for use with the retractable element 1 may be an actuator corresponding to the actuator disclosed in any of the documents WO13091730, WO13093074 or WO12000681, or any other convenient actuator.