WO2019106563A1

WO2019106563A1 - Rotatably-actuated endourethral artificial sphincter

Info

Publication number: WO2019106563A1
Application number: PCT/IB2018/059407
Authority: WO
Inventors: Tommaso MAZZOCCHI; Arianna Menciassi; Leonardo Ricotti
Original assignee: Scuola Superiore Di Studi Universitari E Di Perfezionamento Sant'anna; Inail-Istituto Nazionale Per L'assicurazione Contro Gli Infortuni Sul Lavoro
Priority date: 2017-11-28
Filing date: 2018-11-28
Publication date: 2019-06-06

Abstract

An endourethral artificial sphincter (101) comprises a container (10) configured to be blocked in the patient's urethra (4), a torsionally compliant tubular body (20) fixedly arranged within the container (10) with the longitudinal axis (29) parallel to that (19) of the container (10), comprising two end portions (21, 23) torsionally stiffer, of which the first one (21) is integrally connected to the container (10), and comprising also a torsionally more deformable central portion (22), an opening/closing torsional deformation (8,9) of which brings the torsionally compliant tubular body (20) from an open configuration (A) to a closed configuration (C), causing the inner walls of the central portion (22) to come into contact with each other thus blocking a passageway (24), or vice-versa, the endourethral artificial sphincter (101) also comprising a rotatable actuation cylinder (30) integrally connected to the second end portion (23) of the torsionally compliant body (20), and a magnetic actuation unit (60) having an actuation magnet (66) movably arranged within the container (10), connected to the rotatable actuation cylinder (30) in such a way that a movement (67', 67") of the latter induced by a manoeuvre magnet (90) positioned at a predetermined distance causes an integral rotation (68', 68") of the rotatable actuation cylinder (30) and of the second end portion (23), and twists the central portion (22), thus opening or closing it.

Description

TITLE

ROTATABLY- ACTUATED ENDOURETHRAL ARTIFICIAL SPHINCTER

DESCRIPTION

Field of the invention

[0001] The present invention relates to an artificial sphincter for implant within a urethra, in particular for treating patients who suffer from urinary incontinence.

Technical front and technical problems

[0002] Many types of artificial urethral sphincters are known for treating urinary incontinence. They are used when such remedies as outpatient therapy, the pharmacologic therapy and the pelvic re-education are not successful. Artificial urethral sphincters have been also used as an alternative to traditional surgery techniques, by which the bladder supporting structure are reconstructed.

[0003] WO 2013/144770 describes endourethral sphincters comprising a container and, inside it, a valve element and a safety element for preventing an unwanted opening of the sphincter. Preferably, the valve element comprises a cap shell comprising radial sectors configured to move away from one another upon increase of the patient’s abdominal pressure. In an exemplary embodiment preferred for its reliability, the safety element comprises an abutment member or piston that slidably arranged between a block position, in which it is close to the surface of the shell in order to prevent the latter from opening, and a release position, in which it is at a distance from that surface in order to allow the opening thereof. The piston is maintained in the locking position by a return spring, and can be displaced to the release position by positioning a manoeuvre magnet near the abdomen, said manoeuvre magnet interacting with a magnetic portion of the piston.

[0004] This device is structurally rather complicated. Moreover, the reliability with respect to an unwanted opening can be improved. Another drawback of the devices of WO 2013/144770 is that the manoeuvre magnet must be kept near the abdomen during the whole duration the micturition, which complicates its use.

[0005] US 4,705,518 describes a structure of artificial sphincter comprising two coplanar rings, concentrically and rotatably arranged with respect to each other, the inner ring having a lumen arranged to integrally surround a natural duct of the body of a patient; and also comprising closure members such as rods arranged so that a relative rotation of the two rings about their common axis causes the lumen to be narrowed/enlarged, thus closing/opening the natural duct. In order to rotate the inner ring with respect to the outer ring, and therefore to open/close the sphincter, a radial pin is integrally connected to the inner ring, and a circumferential through slot made in the outer ring allows the pin to protrude outwards so that the patient who bears the sphincter, through a suitable mechanical transmission, can move it along the slot. In an exemplary embodiment, respective series of magnets are arranged along the two rings, so that the attractive interactions established between the magnets of the inner ring and the magnets of the outer ring retain the two rings in relative angular positions that correspond to a closed condition and to an open condition of the sphincter. The rings can be moved away from these relative angular positions by exerting a moment on the inner ring through the pin and the mechanical transmission, said moment exceeding the attractive interactions exerted between the magnets of the two series. Moreover, as mechanical transmission a resilient strip is indicated that is arranged coplanar to the rings and is connected to the pin, so that a compression exerted by the patient towards the sphincter structure causes the pin to be displaced and the inner ring to rotate accordingly.

[0006] In the light of the above, the device of US 4,705,518 comprises magnets to stabilize the relative position of the magnets in the open configuration or in the closed configuration. Instead, a purely mechanical means is provided for causing a relative rotation of the two rings, which makes the device unsuitable for any endourethral application.

[0007 ] Moreover, valve structures are known whose opening/closure is obtained by twisting a deformable duct, as briefly described hereinafter.

[0008] US 5,197,984 describes an artificial sphincter for a colostomy or an ileostomy, comprising an external tubular unit with first and second open ends arranged to be connected to a patient’s peritoneum and skin, respectively, at respective surgical openings; a rotatable ring mounted at the second end; and a torsionally compliant duct arranged in the tubular unit, with open ends connected to the first end of the tubular unit and to the rotatable ring, respectively. By suitably rotating the ring, the patient can cause twist the torsionally compliant duct from an open condition to a twisted closed condition, and vice-versa, thus closing or opening the stoma.

[0009] US 4,620,564 describes a device for precisely regulating the flow rate of a liquid through a catheter, for example for an infusion or a transfusion, without yielding it and suitable for reproducing given flow conditions. The catheter encloses compliant radial“arms” of various shape, converging or integral to a central core and connected to an inner surface of the catheter by short connection portions. The inner lumen is adjusted by a twisting moment directly applied to the outer surface, by rotating two counter rotating bushings arranged coaxially to the catheter and equipped with engagement teeth having longitudinal ribs provided on the catheter outer surface, so as to deform and approach the radial arms to one another. The actuator comprising the two counter-rotating bushings has a radial encumbrance that does not allow the implant within the urethra.

[0010] EP 2 492 606 A1 describes a device for regulating an air flow in a ventilation tube. It comprises two stiff tubular elements, an internal one being rotatably arranged with respect to an external one of them. In order to cause an air flow, a torsionally deformable third tubular element is provided within the internal tubular element. The third element has one end connected to the external tubular element and another end connected to the internal one. This way, by causing the internal tubular element to rotate with respect to the external one, the further internal element is twisted so as to change the passage section of air. Even in this case, a manually operated actuation means is provided to cause the rotation, comprising a helical slot of the internal tubular element and a handle extending from the surface of the internal tubular element through the slot. Even in this case, such an actuation system is unsuitable for an endourethral implant.

[0011] US 2010/068681 describes a lock unit for a catheter. Even in this case, the passageway is adjusted by applying a twisting moment on the outer surface of the catheter. More in detail, two lock elements coaxially and integrally arranged with respect to the catheter are moved away from each other and caused to rotate with respect to each other. This way, the catheter is twisted and its inner lumen is modified, in particular, in order to completely open/block it. Even in this case, the actuation system is unsuitable for an endourethral implant.

[0012] US 4,828,554 describes a check valve for a feeding duct of a for an urine collection container, comprising a duct manufactured with a torsional deformation that normally blocks the inner lumen, and that can be removed by a hydrostatic pressure of an even minimum amount of liquid, which causes the lumen to open and the liquid to flow. Such a valve is not adapted to work as an endourethral sphincter, since does it not allow to accumulate a substantial physiologic amount of liquid in the bladder, i.e. does not allow the urinary continence and allows, on the contrary, a continuous outflow of urine.

[0013] GB 363,365 describes a device for adjusting a flow, in particular a gas flow, comprising a cylindrical valve body and a stopper consisting of a rotatable ring and a plurality of longitudinal rods having respective first rounded ends housed within housings integrally formed in the body-valve and respective second rounded ends, opposite to the first ones, housed within housings integral to the rotatable ring, so that a rotation of the ring causes the rods to be oriented in order to reduce/increase the passage section.

[0014] None of the above-mentioned valve structures, comprising a torsionally compliant stopper, is therefore suitable for use as an endourethral sphincter.

Summary of the invention

[0015] It is therefore a feature of the present invention to provide a sphincter for implant in an urethra that is structurally simpler than the prior art devices.

[0016] It is then a particular feature of the invention to provide such a device that is more reliable against unwanted openings.

[0017] It is also a feature of the invention to provide such a device that is more practical and hygienic to use.

[0018] These and other objects are achieved by an endourethral artificial sphincter comprising: a container having a first longitudinal axis and configured to be blocked within a patient’s urethra;

a torsionally compliant tubular body fixedly arranged within the container, said torsionally compliant tubular body having an own second longitudinal axis parallel to the first longitudinal axis of the container, and comprising: first and a second end portions, the first end portion integral to the container;

a torsionally compliant central portion configured for an opening/closing torsional deformation about the second longitudinal axis,

wherein the torsionally compliant tubular body is configured to reversibly move between:

an open configuration, in which the torsionally compliant central portion defines a passageway in the torsionally compliant tubular body along its own second longitudinal axis,

- a closed configuration, in which inner walls of the torsionally compliant central portion are in contact with one another so as to completely block the passageway in at least one part of the central portion,

the endourethral artificial sphincter also comprising:

a rotatable actuation cylinder, rotatably arranged within the container about the first longitudinal axis,

wherein the second end portion is integrally connected to the rotatable actuation cylinder,

whose main feature is that it also comprises a magnetic actuation unit comprising an actuation magnet movably arranged within the container, the magnetic actuation unit connected to the rotatable actuation cylinder in such a way that a movement of the magnetic actuation unit induced by a manoeuvre magnet positioned at a predetermined distance from said actuation magnet causes an integral rotation of the rotatable actuation cylinder and of the second end portion, thus causing the torsional deformation of the central portion, wherein this movement is selected from the group consisting of:

a closing movement, wherein the rotation causes the closing torsional deformation; an opening movement, wherein the rotation causes the opening torsional deformation.

[0019] This way, all the components of the device comprising a torsionally compliant valve body are contained in the shape of the container, typically a tubular, i.e. cylindrical container. This makes it possible to insert the device into the urethra and to use it as an endourethral sphincter that can be actuated by a manoeuvre magnet; the latter can be an extracorporeal permanent magnet positioned near the patient’s abdomen, or an electromagnet included in the structure of the endourethral sphincter, as described more in detail, hereinafter.

[0020] In an exemplary embodiment, the magnetic actuation unit is a slidable magnetic actuation unit, wherein the closing/opening movement is a closing/opening translation movement, wherein the endourethral artificial sphincter comprises:

an actuation magnet having its poles spaced apart along an own first magnetic axis, and arranged with this first magnetic axis parallel to the first longitudinal axis of the container;

at least one outer radial protrusion, for example in the form of a bolt or of a pin,

wherein:

- the structure comprises a hollow cylindrical guide element arranged within and integral to the container, the hollow cylindrical guide element having at least one first channel having a helical portion;

the rotatable actuation cylinder comprises a channelled part configured to telescopically engage with the guide element at the at least one first channel;

the channelled part has at least one longitudinal second channel;

the at least one outer radial protrusion engages with the at least one first channel and with the at least one second channel;

such that closing/opening translation movement of the magnetic actuation unit brings the at least one outer radial protrusion from an open position to a closed position, or vice-versa along the helical portion of the at least one first channel, and causes the integral rotation of the second end portion and of the rotatable actuation cylinder. [0021] This way, the torsion of the valve body, i.e. of the torsionally compliant tubular body, is actuated by a movement of an actuation magnet that is a translation movement, and that, therefore, can be particularly easily controlled by simply positioning an extracorporeal manoeuvre magnet, which is also axially polarized, proximate to the region of the implant.

[0022] Advantageously, the actuation magnet has a an annular shape, i.e. a shape of a cylindrical annulus, and has its own first magnetic axis, oriented from the South pole to the North pole, coincident with the longitudinal axis of the cylindrical annulus. In particular, the actuation magnet of such a shape is coaxially mounted to the container.

[0023] Preferably, the at least one first channel comprises a linear longitudinal end portion adjacent to the closed position.

[0024] This way, until the at least one protrusion or bolt is in the linear longitudinal end portion of the first channel or channels, a translation movement of the slidable magnetic actuation unit cannot cause any rotation of the rotatable actuation cylinder and, therefore, the tubular body remains in the closed configuration. This prevents any unintentional opening of the sphincter endourethral, for example in occasion of sudden movement of the patient, such as jumps, vehicle jerks, fast stair climbing, and the like. Moreover, owing to this linear longitudinal portion, an amount of urine accumulated upstream of the closed tubular element cannot cause the latter to open, since the rotation of the rotatable actuation cylinder and of the lower end portion of the tubular element is blocked. This is particularly advantageous if the central portion of the tubular element is resiliently torsionally compliant, and is advantageously manufactured in an undeformed rest configuration that corresponds to the open configuration, therefore inner elastic stresses arise in the deformed closed configuration, which tend to recall the tubular body to the open rest configuration.

[0025] Advantageously, the structure comprises an elongated resilient element, in particular a cylindrical helical spring, that has a first end integral to the container and a second end, opposite to the first end, arranged in contact with the actuation magnet, so that the slidable magnetic actuation unit receives a resilient force responsive to its own position along the container. [0026] In an exemplary embodiment, the resilient element is arranged so that the resilient force exerted on the slidable magnetic actuation unit is oriented so as to resist the opening translation movement of the slidable magnetic actuation unit.

[0027] This way, the slidable magnetic actuation unit is always recalled to the closed position. This way, an uncontrolled urine leakage is less probable.

[0028] In an exemplary embodiment alternative to the above exemplary embodiment, the endourethral sphincter comprises a stabilization magnet having its poles spaced apart along an own second magnetic axis, said stabilization magnet fixedly arranged with respect to the container, with the second magnetic axis parallel to the first longitudinal axis of the container, with its poles oriented so as to apply a magnetic force on the actuation magnet, said magnetic force having a direction opposite to the resilient force,

wherein the resilient element and the stabilization magnet are selected in such a way that:

- the magnetic force has an intensity higher than the resilient force when the slidable magnetic actuation unit is located within a predetermined equilibrium distance from the stabilization magnet, and

- the magnetic force has an intensity lower than the resilient force when the slidable magnetic actuation unit is located beyond this equilibrium distance from the stabilization magnet.

[0029] This way, the slidable magnetic actuation unit is recalled/kept in the position corresponding to the closed configuration or to the open configuration of the sphincter according to whether it is closer to the closed position or to the open position, respectively. In other words, the stabilization magnet provides a stable open configuration, besides a stable closed configuration. This makes it possible to move the extracorporeal manoeuvre magnet away from the region of the implant while maintaining the open configuration, during the whole duration the micturition, and that is therefore more practical and hygienic to use.

[0030] Advantageously, the stabilization magnet has a an annular shape i.e. a shape of a cylindrical annulus, and has an own second magnetic axis, oriented from the South pole to the North pole, coincident with the longitudinal axis of the cylindrical annulus. In particular, the actuation magnet of such a shape is coaxially mounted to the container.

[0031] Preferably,

the resilient element and the stabilization magnet are arranged at one end portion of the container opposite to the torsionally compliant tubular body with respect to the guide element;

- the resilient element is mounted so as to be compressed when the slidable magnetic actuation unit is in a position corresponding to the closed configuration the torsionally compliant tubular body;

- the stabilization magnet is arranged with its own second magnetic axis oriented in the same way as the first magnetic axis of the slidable actuation magnet, so that the magnetic force is a magnetic attractive force directed towards the stabilization magnet.

[0032] This way, both the stabilization magnet and the resilient element can be mounted at the end of the assembly of the sphincter, after the magnetic actuation unit. This simplifies the construction of the artificial sphincter and allows to use parts that are easy to manufacture.

[0033] In a second exemplary embodiment,

the magnetic actuation unit is a magnetic rotatable actuation unit and the closing/opening movement of the magnetic actuation unit is an opening/closing rotation;

the magnetic rotatable actuation unit comprises an actuation magnet having its poles spaced apart along an own first magnetic axis oriented from the South pole to the North pole of the actuation magnet;

- the actuation magnet is integrally mounted to the rotatable actuation cylinder with the first magnetic axis transversally arranged, in particular perpendicularly, with respect to the first longitudinal axis of the container; the endourethral sphincter also comprises:

a stabilization magnet having its poles spaced apart along an own second magnetic axis oriented from the South pole to the North pole of the stabilization magnet, and connected to the container with the second magnetic axis transversally arranged, in particular perpendicularly arranged, with respect to the first longitudinal axis of the container, the stabilization magnet arranged with an own reference pole in an angular reference position of the container, so as to apply a magnetic moment on the actuation cylinder, through the actuation magnet, said magnetic moment responsive to the direction the first magnetic axis of the actuation magnet with respect to the second magnetic axis of the stabilization magnet,

two abutment elements integral to the container arranged at predetermined respective abutment angles, in particular equal to each other, from the angular reference position,

an abutment member peripherally connected to the actuation cylinder at a predetermined abutment angle with respect to the pole of the actuation magnet having a name opposite to the reference pole of the stabilization magnet, in particular the abutment member arranged at the pole having a name opposite to the reference pole, the abutment member arranged to abut against the two abutment elements;

the lower portion of the tubular body is connected to the actuation cylinder in such a way that, when the abutment member is arranged in a first abutment position against a first abutment element of the two abutment elements, the tubular body is in the closed configuration, whereas, when the abutment member is arranged in a second abutment position against a second abutment element of the two abutment elements, the tubular body is in the open configuration.

[0034] This way, by causing the rotatable actuation cylinder to carry out a rotation by displacing the abutment member from the first abutment position or from the second abutment position, the magnetic moment can recall the rotatable actuation cylinder to the first abutment position or to the second abutment position, respectively, and can move the tubular body back to the closed configuration or to the open configuration, respectively, or can attract the rotatable actuation cylinder to the second abutment position or to the first abutment position, respectively, and can move the tubular body to the open configuration or to the closed configuration, respectively, according to whether, in this rotation, the second magnetic axis of the actuation magnet is brought beyond or is not brought beyond a position in which the second magnetic axis has an orientation opposite to the first magnetic axis. [0035] Advantageously, the actuation magnet and/or the stabilization magnet has a an annular shape i.e. the shape of a cylindrical annulus, and its second magnetic axis is arranged perpendicularly to the longitudinal axis of the respective cylindrical annulus, the North and South poles comprising two opposite halves of a same cylindrical annulus. In particular, the actuation magnet and/or the stabilization magnet, which have such a shape, is/are mounted coaxially to the container.

[0036] In a third exemplary embodiment,

the magnetic actuation unit comprises a motor comprising:

a stator co-axial and integral to the container;

a rotor rotatably arranged within the stator and integrally connected with the actuation cylinder,

the rotor comprises an actuation magnet having its poles spaced apart along an own first magnetic axis radially arranged with respect to the stator, the stator comprises:

two stabilization magnets angularly spaced apart from each other by a predetermined angle having a vertex on the first longitudinal axis, the stabilization magnets having their poles spaced apart along respective seconds magnetic axes, radially oriented with respect to the stator and having the same direction as the first magnetic axis, in other words, the respective seconds magnetic axes of the stabilization magnets are radially arranged with respect to the stator and are oriented in the same way as the magnetic axis when the first magnetic axis of the actuation magnet, by rotating along with said rotor, becomes aligned with the second magnetic axis of one of the stabilization magnets;

a plurality of manoeuvre electromagnets arranged so that the first magnetic axis is substantially aligned with the winding axes when the rotor is in respective angular positions;

the lower portion of the tubular body is connected to the actuation cylinder in such a way that, when the actuation magnet is facing a first stabilization magnet of the two stabilization magnets, the tubular body is in the closed configuration, whereas, when the actuation magnet is facing a second stabilization magnet of the two stabilization magnets, the tubular body is in the open configuration,

the endourethral sphincter comprises a control unit configured to selectively and consecutively supply a manoeuvre electric current to the manoeuvre electromagnets, the manoeuvre electric current having an intensity selected in such a way that the rotor rotates, bringing the actuation magnet to consecutively face the manoeuvre electromagnets.

[0037] This way, by selectively and consecutively supplying the manoeuvre electric current to the manoeuvre electromagnets, the rotor rotates, causing the actuation magnet to move from a position facing the first stabilization magnet to a position facing the second stabilization magnet, or vice-versa, and bringing the tubular body from the closed configuration to the open configuration, or vice- versa, respectively.

[0038] Preferably, the plurality of manoeuvre electromagnets comprises a plurality of windings of coils of an electrically conductive material transversally arranged, in particular perpendicularly arranged, with respect to respective winding axes radially arranged with respect to the stator.

[0039] Advantageously, the torsionally compliant tubular body comprises a plurality of flexible longitudinal walls arranged within the central portion, and the passageway is a multiple passageway defined by the inner walls comprising walls of the flexible longitudinal walls and walls of the central portion, where the walls of the flexible longitudinal walls are arranged to move towards/away from each other in the opening/closing torsional deformation of the central portion in such a way that, in the closed configuration, the flexible longitudinal walls are in contact with one another so as to completely block the multiple passageway in the longitudinal portion of the central portion.

[0040] This way, only a relatively small rotation of the rotatable actuation cylinder is required to tightly close the sphincter. This reduces the cyclical stress of the material of the valve body, which prolongs the service life of the same.

[0041] In particular, the flexible longitudinal walls are radially arranged and converge towards the longitudinal axis of said torsionally compliant tubular body, more in particular, the radial walls are two or three, so that said passageway both split into corresponding independent channels. Brief description of the drawings.

[0042] The invention will be now shown with the description of some exemplary embodiments, exemplifying but not limitative, with reference to the attached drawings, in which the same reference characters designate the same or similar parts, throughout the figures of which:

Fig. 1 shows an endourethral sphincter arranged in a urethra;

Fig. 2 is an elevation side view of an endourethral sphincter according to the invention;

Figs. 3, 4 and 5 are cross sectional partial views of the endourethral sphincter of Fig. 2 in a closed configuration, in a partially open configuration and in an open configuration, respectively;

Figs. 6, 7 and 8 are perspective, side and cross sectional views, respectively, of the torsionally compliant tubular body, according to an exemplary embodiment, in the open configuration;

- Figs. 9, 10 and 1 1 are perspective, side and cross sectional views, respectively, of the torsionally compliant tubular body of Figs. 6, 7 and 8, in the closed configuration;

Figs. 12, 13 and 14 are perspective, side and cross sectional views, respectively, of the torsionally compliant tubular body, according to a different exemplary embodiment, in the open configuration;

Figs. 15, 16 and 17 are perspective, side and cross sectional views, respectively, of the torsionally compliant tubular body of Figs. 12, 13 and 14, in the closed configuration;

Fig. 18 is an exploded perspective view of an endourethral sphincter in a bistable modification, according to a first exemplary embodiment of the invention;

Fig. 19 is a longitudinal section view of the rotatable actuation cylinder of the endourethral sphincter of Fig. 18;

Figs. 20 and 21 are partial cross sectional side views of the endourethral sphincter of Fig. 18, in which the rotatable actuation cylinder is removed, in the closed and open configurations, respectively;

Figs. 22-25 diagrammatically show an opening, discharging and closing cycle of the endourethral sphincter of Figs. 18-20; Fig. 26 is a diagram showing the forces exerted on the slidable magnetic actuation unit by the spring, by the stabilization magnet and by the manoeuvre magnet, through the slidable actuation magnet;

Fig. 27 is an exploded perspective view of an endourethral sphincter still according to the first exemplary embodiment, but in a monostable modification;

Figs. 28 and 29 are partial cross sectional side views of the endourethral sphincter of Fig. 27, in which the rotatable actuation cylinder is removed, in the closed and open configurations, respectively;

Fig. 30 is an exploded perspective view of an endourethral sphincter in a bistable modification, according to a second exemplary embodiment of the invention;

Fig. 31 is a cross sectional view of the endourethral sphincter of Fig. 30 at the height of the abutment member of the actuation cylinder and of the abutment elements of the container;

Figs. 32A-35B diagrammatically show an opening, discharging and closing cycle of the endourethral sphincter of Figs. 30 and 31 ;

Fig. 36 is a diagram showing the moment exerted on the actuation cylinder by the stabilization magnet, through the rotatable actuation magnet;

Fig. 37 is an exploded perspective view of a bistable endourethral sphincter, according to a third exemplary embodiment of the invention;

Fig. 38 is an elevation side view of the endourethral sphincter of Fig. 38, in which the container is removed;

Figs. 39 and 40 are cross sectional views of the endourethral sphincter of Fig. 38 made at the driven actuator, according to two different exemplary embodiments of the rotor;

Figs. 41 -46 diagrammatically show an opening, discharging and closing cycle of the endourethral sphincter of Figs. 37-40.

Description of a preferred exemplary embodiment

[0043] With reference to Fig. 1 , an endourethral artificial sphincter 100 is diagrammatically shown arranged in a subject’s urethra 4.

[0044] As shown more in detail in Fig. 2, endourethral sphincter 100 comprises a container 10, preferably a cylindrical container having a longitudinal axis 19 and having engagement means 12,13 to engage with the inner walls 3 of urethra 4, downstream of a subject’s bladder 1 (Fig. 1 ), so as to stably arrange endourethral sphincter 100 within urethra 4. In the case of Fig. 2, the engagement means can comprise an upper stent 12 and a lower stent 13 connected to container 10 through a locking system 1 1. For instance, upper and lower stents 12,13 can comprise coils 15 configured to radially expand at the end portions of urethra 4 (Fig. 1 ). In an alternative exemplary embodiment, not shown, the endourethral sphincter can comprise stents having shape memory flared end portions, which can be integral with container 10. In another exemplary embodiment, not shown, the engagement means comprises at least one balloon inflatable with a liquid or with air, arranged to expand and keep the endourethral sphincter in its position within urethra 4.

[0045] Figures 3, 4 and 5 show an upper portion B of endourethral sphincter 100 of Fig. 2 in longitudinal section views. A torsionally compliant tubular valve body 20 is arranged within container 10, comprising two torsionally substantially stiff ring end portions 21 ,23, in particular equal to each other, and a central portion 22 torsionally compliant about a longitudinal axis 29 of tubular body 20 and defining an inner lumen 24. For instance, central portion 22 can be manufactured as a cylindrical portion, in particular having a substantially elliptical cross section (Figs. 8,10).

[0046] In particular, Fig. 3 shows tubular body 20 in a closed configuration C, in which it is torsionally deformed about its axis 29 and the generatrices of the inner surface of central portion 22 of tubular body 20 are in contact with one another for a predetermined length, thus forming a seal arranged to prevent the flow of a liquid, i.e. urine, 5 that can be present in bladder 1 (Fig. 1 ) and in the upper portion of blocked lumen 24.

[0047] Tubular body 20 is connected to container 10 by its own upper end portion 21 , which can be arranged between an inner ring projection 16 of container 10 and an upper removable lock ring 41 , in order to prevent both the longitudinal translation movement of tubular body 20 within container 10, and the rotation of the upper end portion 21 about axis 19 of container 10 coincident with axis 29 of tubular body 20.

[0048] Figs. 4 and 5 show tubular body 20 in an opening-beginning or partially open configuration and in an open configuration, respectively. Tubular body 20 can move from the closed configuration of Fig. 3 to the open configuration of Fig. 5, in which urine 5 can cross lumen 24 without facing any substantial resistance, and vice-versa, under an opening twisting moment 8 and of a closing twisting moment 9, respectively.

[0049] Figs. 6, 7 and 8 are perspective, side and cross sectional views, respectively, of torsionally compliant tubular body 20 according to an exemplary embodiment of the invention, in the open configuration, whereas Figs. 9, 10 and 1 1 are corresponding views thereof in the closed configuration. In this exemplary embodiment, torsionally compliant tubular body 20 has a diametrically arranged longitudinal dividing wall, i.e. two radially arranged longitudinal walls 25 at 180° from each other, which divide passageway 24 into two independent channels.

[0050] Figs. 12-17 are views of torsionally compliant tubular body 20 according to another exemplary embodiment of the invention respectively corresponding to the views of Figs. 6-1 1 , in which three radially arranged longitudinal walls 25 are provided, typically at 120° from each other, which divides passageway 24 into three independent channels.

First exemplary embodiment, bistable modification

[0051] Fig. 18 is an exploded perspective view of an endourethral sphincter 101 according to a first exemplary embodiment of the invention, in a first bistable modification. Tubular body 20 is shown along with the components used to actuate the torsion thereof, according to this exemplary embodiment, comprising a rotatable actuation cylinder 30, a guide element 50, a slidable magnetic actuation unit 60, a resilient element 70 and a stabilization magnet 80. Container 10 is shown in a section perspective view, actually only a semicylindrical half thereof is shown.

[0052] More in detail, actuation cylinder 30 is coaxially and rotatably arranged within container 10, and is integrally connected with lower portion 23 of tubular body 20. In order to fasten tubular body 20 to actuation cylinder 30, in this exemplary embodiment, actuation cylinder 30 can have an inner ring projection 36, and lower end portion 23 of tubular body 20 is tightened between inner ring projection 36 (see also Figs. 3-5) and a lower lock ring 42. Fig. 19 shows lower lock ring 42 and longitudinal flexible portions 33 of actuation cylinder 30 in dashed line, when being assembled, and in solid line once mounted. [0053] Since upper portion 21 of tubular body 20 cannot rotate about its axis

29 (Fig. 18), as indicated above, a rotation 68’, 68” of rotatable actuation cylinder

30 causes a twisting of tubular body 20, for example as indicated in Fig. 1 1 or in Fig. 17.

[0054] In the exemplary embodiment as depicted, the actuation rotational movement 68’, 68” of rotatable actuation cylinder 30 is caused by a translation movement 67’, 67” of slidable magnetic actuation unit 60, which is arranged to slide and rotate about axis 19 within container 10.

[0055] In order that translation movement 67’, 67” of slidable magnetic actuation unit 60 causes rotation 68’, 68” of rotatable actuation cylinder 30, guide element 50 co-axial and integral to container 10 has a channelled part 55 in which a first channel 56 is provided having a substantially helical portion 51. In order to be fixed to container 10, guide element 50 can have lock teeth 53 radially protruding outside of guide element 50 and configured to engage with lock channels 14 provided at an end portion of container 10.

[0056] Moreover, in order to perform rotation movement 68’, 68”, rotatable actuation cylinder 30 comprises a channelled part 35 providing at least one linear longitudinal second channel 31. Rotatable actuation cylinder 30 can be configured to telescopically engage with channelled part 55 of guide element 50, in particular as shown, rotatable actuation cylinder 30 internally provides a housing 37 (Fig. 19) configured to pivotally and slidably receive channelled part 55 of guide element 50. Moreover, slidable magnetic actuation unit 60 comprises at least one protrusion, such as a bolt 62, that radially extends therefrom and engages both with first channel 56 of guide element 50 and with second channel 31 of rotatable actuation cylinder 30, crossing both channels 31 ,56. Since guide element 50 is integrally connected to container 10, when slidable magnetic actuation unit 60 translates along hollow container body 10, slidable magnetic actuation unit 60 is forced to rotate about axis 19 and, since it engages with second channel 31 by pin 62, it forces rotatable actuation cylinder 30 also to rotate about axis 19.

[0057] Preferably, as mentioned above, channelled part 35 of rotatable actuation cylinder 30 comprises longitudinal flexible portions 33, in order to assist the assembly of lower lock ring 42 in the upper part of housing 37 of rotatable actuation cylinder 30, as shown in already described Fig. 19. In order to increase the flexibility of longitudinal portions 33, longitudinal linear second channels 31 can have circumferential extensions 34, at the end opposite to the free end of longitudinal portions 33.

[0058] Still with reference to Fig. 18, in the present exemplary embodiment, slidable magnetic actuation unit 60 comprises a slidable actuation magnet 66 and, preferably, a support 61 for actuation magnet 66. In this exemplary embodiment, slidable actuation magnet 66 is an axially polarized magnet, i.e. it has the North pole N and the South pole S spaced apart along a longitudinal axis. The longitudinal axis is substantially arranged along axis 19 of container 10. Slidable actuation magnet 66 preferably has an annular shape, i.e. the shape of a hollow cylinder i.e. of a cylindrical annulus. Support 61 of slidable actuation magnet 66 can comprise longitudinal flexible portions 64 providing outwards protruding lock teeth 65, in order to allow a click-lock assembly of magnet 66 on support 61. A portion of support 61 can have housing holes 63 for pins 62.

[0059] Still with reference to Fig. 18, stabilization magnet 80 is arranged in container 10, in this case, at an end of container 10 opposite to the end where tubular body 20 is arranged. Stabilization magnet 80 is mounted with a pole, in this case the North pole N, facing the opposite pole, in this case the South pole S, of slidable actuation magnet 66, in other words stabilization magnet 80 and actuation magnet 66 are arranged with their magnetic axes, oriented in the same way from respective South poles to respective North poles. For this reason, between magnets 66,80 an attractive magnetic force F_m is established, responsive to the mutual distance, i.e. depending on translation movement 67’, 67” of slidable magnetic actuation unit 60. The relationship between magnetic attractive force F_m and this translation movement is qualitatively shown in Fig. 26.

[0060] Resilient element 70, in this exemplary embodiment, is an elongated resilient element, for example a conventional cylindrical helical spring 70, which has a first end 71 integral to container 10 and a second end 72, opposite to first end 71 , in contact with slidable magnetic actuation unit 60. In this case, second end 72 of elongated resilient element 70 is attested against actuation magnet 66. Elongated resilient element 70 is mounted so as to be compressed when slidable magnetic actuation unit 60 with slidable actuation magnet 66 is in a position along container 10 corresponding to the closed configuration of endourethral sphincter 101 , as shown in Fig. 20. Therefore, a repulsive resilient force Fe is established, i.e. a force that tends to move slidable magnetic actuation unit 60 away from the end of sphincter 101 , where stabilization magnet 80 is arranged, in other words a force opposite to above-mentioned attractive magnetic force Fm, established between magnets 66 and 80. The relationship between repulsive resilient force Fe and the displacement of slidable magnetic actuation unit 60 with respect to the end of sphincter 101 is qualitatively shown in Fig. 26, and is typically a linear relationship, according to an elastic constant of elongated resilient element 70.

[0061] More in detail, the elastic constant of elongated resilient element 70, the features of magnets 66,80, as well as the position and the length of channelled part 55 of guide element 50, are selected in such a way that in the position corresponding to the closed configuration, attractive magnetic force F_m is higher than repulsive resilient force F_e, which maintains slidable magnetic actuation unit 60 in a retracted position with respect to tubular body 20, and provides therefore a stable closed configuration C, as it can be seen at the point of abscissa C of the diagram of Fig. 26.

[0062] First channel 56 can advantageously comprise a linear longitudinal end portion 52, also shown in Figs. 20 and 21 , parallel to axis 19 of container 10, corresponding to the closed configuration C (Fig. 20) of endourethral sphincter 101 , i.e. adjacent to one end of the helical portion 51 farther from tubular body 20. As long as the protrusion or each protrusion i.e. bolt 62 is in the linear longitudinal end portion 52, opening translation movement 67” of slidable magnetic actuation unit 60 cannot cause the rotation of rotatable actuation cylinder 30, and therefore tubular body 20 remains in the closed configuration C. This is useful to prevent any unintentional opening of tubular valve body 20. Such an event could happen if tubular body 20 is made of a resilient material, which would tend to move tubular body 20 from the closed configuration C to the open configuration A, which is typically the natural configuration in which tubular body 20 is manufactured. Moreover, an unintentional opening could occurring in occasion of sudden movement of the patient, such as jumps, vehicle jerks, fast stair climbing, and the like. [0063] On the other hand, in the position corresponding to the open configuration to endourethral sphincter 101 , as shown in Fig. 21 , repulsive resilient force F_e is higher than attractive magnetic force F_m, providing therefore also a stable open configuration, as it can be seen at the point of abscissa A in the diagram of Fig. 26.

[0064] Endourethral sphincter 101 is therefore a bistable device, i.e. it has two stable conditions, both at its own closed configuration C (Fig. 20) and at its open configuration A (Fig. 21 ). In other words, without external actions, endourethral sphincter 101 is configured to maintain its closed configuration C and its open configuration A.

[0065] Still with reference to Fig. 18, also stabilization magnet 80 has preferably an annular shape. In this case, resilient element 70, in particular spring 70, can be co-axial to magnets 66,80 and have the first end leaning on stabilization magnet 80.

[0066] In order to fasten stabilization magnet 80 to container 10, endourethral sphincter 101 can comprise a lock ring 43. Lock ring 43 can be mounted by an interference fit coupling to the flexible end portion of container 10, at channels 14, and can provide lock teeth 1 1’ protruding inwards of container 10.

[0067] The operation of endourethral sphincter 101 is described with reference to Figs. 22-25. Fig. 22 shows endourethral sphincter 101 in the closed configuration C. As indicated in Fig. 23, to open sphincter 101 , the patient positions a manoeuvre magnet 90 near the abdomen, and direct it so that one of its poles, in this case its South pole, is oriented towards the homonymous pole of slidable actuation magnet 66 (Fig. 20). This way, a repulsive opening manoeuvre force FM’ is established between manoeuvre magnet 90 and slidable actuation magnet 66.

[0068] The features of manoeuvre magnet 90 and its positioning to cause the endourethral sphincter 101 to open are selected in such a way that the overall force acting on slidable magnetic actuation unit 60 (Fig. 18), i.e. the resultant of forces FM’, F_m, F_e application it respectively by manoeuvre magnet 90, from stabilization magnet 80 and by resilient element 70 is oriented towards the end of container 10 farthest by manoeuvre magnet 90, so as to cause translate slidable magnetic actuation unit 60 in this direction and cause the opening endourethral sphincter 101.

[ 0069] In other words, as shown in Fig. 26, the overall repulsive force FM +Fm exerted by two magnets 80,90 on slidable actuation magnet 66 becomes higher than force F_e of spring 70, so that slidable magnetic actuation unit 60 is brought from the position corresponding to the point of abscissa C, i.e. from the closed configuration C, to the point of abscissa A, i.e. to the open configuration A, which can be arranged in a region where repulsive resilient force F_e is higher than attractive force F_m exerted on slidable actuation magnet 66 by stabilization magnet 80 alone. Therefore, as shown in Fig. 24, even if manoeuvre magnet 90 is removed, i.e. moved indefinitely away from endourethral sphincter 101 , slidable magnetic actuation unit 60 remains in position A and torsionally compliant tubular body 20 remains in the open configuration A.

[ 0070 ] As shown in Fig. 25, in order to close sphincter 101 , manoeuvre magnet 90 is used again, but this time is positioned so that one of is poles, in this case the North pole, is oriented towards the opposite pole, in this case the South pole, of slidable actuation magnet 66. This way, an attractive closing manoeuvre force FM” is established between manoeuvre magnet 90 and slidable actuation magnet 66 in such a way that, with the prefixed features of manoeuvre magnet 90, the overall force acting on slidable magnetic actuation unit 60, i.e. the resultant of forces FM”, F_m, F_e, is oriented towards manoeuvre magnet 90, so as to cause slidable magnetic actuation unit 60 to translate in this direction and recall it to the position C corresponding to the closed configuration C, as also shown in Fig. 25.

[ 0071 ] In an exemplary embodiment of the first exemplary embodiment, not shown, stabilization magnet 80 is mounted with a pole facing the homonymous pole of slidable actuation magnet 66, for example with South pole facing South pole or with North pole facing North pole. In this case, a known repulsive magnetic force F_m is established between magnets 66,80, depending on distance d. In this case, provided that structural modification are made that are evident for a skilled person, spring 70 can be mounted so as to be stretched when slidable magnetic actuation unit 60 along with slidable actuation magnet 66 is in a position along container 10 corresponding to the open configuration of endourethral sphincter 101 , similarly to what is shown in Fig. 21. In this case, an attractive resilient force F_e is established, i.e. a resilient force F_e that tends to approach slidable magnetic actuation unit 60 to the end of sphincter 101 where stabilization magnet 80 is arranged, i.e., also in this case, a force of direction opposite to repulsive magnetic force F_m, described above, which arises between magnets 66 and 80. The opening and closing manoeuvres can be easily deducted by the skilled person from what is described here with reference to Figs. 22-25.

First exemplary embodiment, monostable modification

[0072] Fig. 27 shows an endourethral sphincter 1 10 still according to the first exemplary embodiment of the invention, but in a second monostable modification, in which the closed configuration only is provided as a stable configuration, while the open configuration must be maintained by the patient, as described hereinafter. Figs. 28 and 29 show endourethral sphincter 110 in the closed configuration C and in the open configuration A, respectively.

[0073] Endourethral sphincter 1 10 differs from endourethral sphincter 101 of the bistable modification in that it does not comprise any stabilization magnet 80, and in that resilient element 70 is arranged to be extended, with respect to its own rest configuration, when slidable magnetic actuation unit 60 is in a position along container 10 corresponding to the open configuration to endourethral sphincter 101 , as shown in Fig. 29. In this way, in such conditions slidable magnetic actuation unit 60 receives a resilient force F_e that tends to bring it back to the closed configuration. As also indicated in Fig. 29, in order to open sphincter 1 10, a manoeuvre magnet 90 is positioned so that one of its poles, in this case the South pole, is oriented towards the homonymous pole of slidable actuation magnet 66. Therefore, a repulsive opening manoeuvre force FM is established between manoeuvre magnet 90 and slidable magnetic actuation unit 60. The features of manoeuvre magnet 90, and the position in which this is positioned for opening, are selected in such a way that the repulsive opening manoeuvre force FM is higher than resilient force F_e. Manoeuvre magnet 90 is maintained in this position until one decides to close endourethral sphincter 1 10 again. By suitably moving away manoeuvre magnet 90, slidable magnetic actuation unit 60 only receives resilient force F_e, which causes it to move back to the closed position, corresponding to the closed configuration C.

Second exemplary embodiment

[0074] Fig. 30 shows an endourethral sphincter 102 according to a second exemplary embodiment of the invention, in an diagrammatical exploded view. In this case, in order to twist tubular body 20, endourethral sphincter 102 comprises an actuation cylinder 130, a magnetic rotatable actuation unit with an actuation magnet 166, and a stabilization magnet 180.

[0075] More in detail, actuation cylinder 130 is coaxially and rotatably arranged within container 10, and is integrally connected with lower portion 23 of tubular body 20, for example by an inner ring projection 36 of rotatable actuation cylinder 130 and by a lock ring, in the same way as indicated in Fig. 19 for endourethral sphincter 101 according to the first exemplary embodiment. Also in this case, upper portion 21 of tubular body 20 cannot rotate about axis 29, and therefore a rotation 68’, 68” of rotatable actuation cylinder 130 causes a twisting of tubular body 20 from the closed configuration to the open configuration, or vice-versa.

[0076] Actuation magnet 166 has its poles spaced apart along an own first magnetic axis 169 conventionally oriented from the South pole to the North pole, and is integrally mounted to rotatable actuation cylinder 130 with this first magnetic axis 169 transversally arranged, in this case perpendicularly arranged, with respect to longitudinal axis 19 of container 10. Actuation magnet 166 is integrally mounted to actuation cylinder 130. Preferably, actuation magnet 166 has an annular shape i.e. a hollow cylinder shape, and is mounted coaxially to container 10. In this case, actuation magnet 166 is a diametrical magnet and has the North pole and the South pole arranged in diametrically opposite own portions, in particular its two poles are opposite semicylindrical portions thereof.

[0077] In order to mount actuation magnet 166, actuation cylinder 130 preferably has longitudinal channels 31 that can comprise circumferential extensions 34 made at the ends opposite to their free ends. This way, longitudinal flexible portions 33 are provided, so as to lock actuation magnet 166 in a click engagement with lock teeth 38 protruding inwards of channelled part 35 of actuation cylinder 130. [0078] Stabilization magnet 180 is integrally mounted to container 10, in particular at one end of container 10 opposite to the end where tubular body 20 is arranged. Also this magnet has an own second magnetic axis 189 S-N transversally arranged, in particular perpendicularly arranged, with respect to first longitudinal axis 19. Preferably, stabilization magnet 180 has an annular shape i.e. a hollow cylinder shape, in which case it is a diametrical magnet with own North pole and South pole arranged at own diametrically opposite portions, in particular the two poles form opposite semicylindrical portions thereof.

[0079] In this way, a stabilization magnetic moment M_m is established between actuation magnet 166 and stabilization magnet 180 depending on the relative angular position of the respective first and second magnetic axis 169,189, i.e. responsive to the rotation 67’, 67” of actuation magnet 166, since stabilization magnet 180 is a stationary magnet. The stabilization magnetic moment M_m established between two magnets rotatably arranged about a common axis, like magnets 166,180, with no limitations to relative rotation, depends on angle y formed by respective S-N-oriented magnetic axes 169,189 as qualitatively shown in Fig. 36. In particular, angle y is 0 when the homonymous poles of the two magnets overlaps, i.e. the North pole of actuation magnetic axis 169 and the North pole of stabilization magnetic axis 189 overlap, and therefore the South pole of actuation magnetic axis 169 and the South pole of stabilization magnetic axis 189 overlap as well. Stabilization magnetic moment M_m is zero when the two magnetic axes 169,189 overlaps, i.e. at points Ei and E2. These points correspond to equilibrium conditions.

[0080] Moreover, in point E-i, where g = ±180°, magnetic axes 169,189 are oriented in the same way, i.e. the homonymous poles of magnets 166,180 overlap. In these conditions, actuation magnet 166 is in an instable equilibrium position with respect to stabilization magnet 180. In fact, a rotation in given sense of actuation magnet 166 causes a magnetic moment M_m acting on it in the same sense, which causes actuation magnet 166 to move away from the starting position corresponding to E-i.

[0081] In point E2, where y = 0°, magnetic axes 169,189 are oriented in a opposite way with respect to each other, i.e. the North pole of a magnet and the South pole of the other magnet overlap, and vice-versa. In these conditions, actuation magnet 166 is in a stable equilibrium position with respect to stabilization magnet 180. In fact, a rotation in given sense of actuation magnet 166 causes a magnetic moment M_m acting on it in the opposite sense, which tends to cause actuation magnet 166 to move back to the starting position corresponding to E2.

[ 0082 ] The absolute value of stabilization magnetic moment M_m has a maximum value when the two oriented axes are perpendicular to each other, i.e. when Y = -90° or when g = +90°, at points Mi and M2, respectively, as shown in Fig. 36.

[ 0083 ] Still with reference to Fig. 30, container 10 comprises two abutment elements 1 7,18, for example formed by respective radial protrusion of container 1 0 arranged at respective angles Q17 and Q18 from a predetermined reference pole 188 of stabilization magnet 180, for example, in this case, from the South pole. Actuation cylinder 130 comprises an abutment member 139, for instance, formed by an axial protrusion extending from a ring end surface 131 of actuation cylinder 130. Actuation magnet 166 is mounted to actuation cylinder 130 in such a way that pole 168 of actuation magnet 166 having a name opposite to reference pole 188 of stabilization magnet 180, in this case the North pole, is arranged at abutment member 139. Moreover, actuation cylinder 130 is mounted with abutment member 139 rotationally located between abutment elements 17 and 18 of container 10, on the same side as the pole 187 of stabilization magnet 180 opposite to reference pole 188, in this case on the same side as the North pole.

[ 0084 ] With the above-described arrangement, actuation cylinder 130 can rotate in such a way that North pole 168 of actuation magnet 166 spaces between the positions indicated by points S17 and S18 in Fig. 36. These positions are both stable equilibrium positions, since an angular displacement starting from point S17 or S18 and narrower than |180°-qΐ7| and |180^o-qib|, respectively, brings actuation cylinder 130 to a position where magnetic moment M_m causes it to move back to starting position S17 or S18, respectively.

[ 0085 ] Lower portion 23 of tubular body 20 is connected to actuation cylinder 130 in such a way that, when abutment member 139 abuts against abutment element 17, i.e. is in position S17 of Fig. 36, tubular body 20 is in the closed configuration, as shown in Figs. 32A and 32B, whereas, when abutment member 139 abuts against abutment element 18, i.e. is in position S-ie of Fig. 36, tubular body 20 is in the open configuration, as shown in Figs. 33A and 33B.

[0086] Stabilization magnet 180 can be fixed to container 10 in the same way (Fig. 19) as stabilization magnet 80 of endourethral sphincter 101 of Fig. 18. Moreover, in order to contain actuation cylinder 130 and actuation magnet 166 a lock ring 150 can be provided having radially protruding lock teeth 153, configured to engage with lock channels 14 provided at the end of container 10.

[0087] The operation of endourethral sphincter 102 is now described with reference to Figs. 32A-35B. As mentioned above, Figs. 32A and 32B show endourethral sphincter 102 in the closed configuration. As indicated in Figs. 34A and 34B, in order to open sphincter 102, a manoeuvre magnet 190 is used which also is diametrically polarized, and has for example the shape of a circular disc. The manoeuvre magnet is positioned substantially co-axially to container 10, and therefore also to actuation magnet 166 and to stabilization magnet 180, and with one pole angularly arranged at the opposite pole of actuation magnet 166. The features of manoeuvre magnet 190 and of stabilization magnet 180 are selected in such a way that, in these conditions, the overall moment acting on actuation magnet 166, i.e. the sum of stabilization moment Mm and of a manoeuvre moment MM, has the sense suitable to cause actuation cylinder 130 to rotate away from position S17.

[0088] In order to open endourethral sphincter 102, manoeuvre magnet 190 can be rotated in the same sense as actuation cylinder 130 must be rotated, by an angle wider than 180°- Q17 (Figs. 34A-35B), so as to move it away from actual position S17 and to bring it beyond point E1 (Fig. 36), where stabilization moment Mm changes its sense. As an alternative, manoeuvre magnet 190 can be positioned, since the beginning, in an angular position from where it applies to actuation magnet 160 a manoeuvre moment MM suitable to cause actuation magnet 160 to rotate and to bring its pole 168 beyond point E-i. By removing manoeuvre magnet 190, i.e. by moving it indefinitely away from endourethral sphincter 102, actuation cylinder 130 moves to stable equilibrium position S-ie, corresponding to abutment element 18, under the action of the stabilization moment M_m only, and tubular body 20 reaches the open configuration as shown in Figs. 33A and 33B.

[0089] Similarly, in order to close again endourethral sphincter 102, manoeuvre magnet 190 can be rotated in the same sense as actuation cylinder 130 must be rotated, by an angle wider than 180°- q-ib (Figs. 35B-34A), so as to move it away from actual position Sis and to bring it beyond point Ei (Fig. 36), where stabilization moment M_m changes its sense. Even in this case, as an alternative, manoeuvre magnet 190 can be positioned since the beginning in an angular position, from where it applies to actuation magnet 160 a manoeuvre moment MM suitable to cause actuation magnet 160 to rotate and to bring its pole 168 beyond point E-i. By removing manoeuvre magnet 190, i.e. by moving it indefinitely away from endourethral sphincter 102, actuation cylinder 130 moves to stable equilibrium position S17, corresponding to abutment element 17, under the action of the stabilization moment M_m only, and tubular body 20 reaches the closed configuration as shown in Figs. 32A and 32B

Third exemplary embodiment

[0090] Figs. 37 and 38 show an endourethral sphincter 103 according to a third exemplary embodiment of the invention, respectively in an diagrammatical exploded view and in an elevation side view in which container 10 is removed. In this case, in order to cause tubular body 20 to twist, endourethral sphincter 103 comprises a rotatable actuation cylinder 230, a motor 260 and a control unit 290 of motor 260.

[0091] More in detail, actuation cylinder 230 is rotatably and coaxially arranged within container 10, and is integrally connected to lower portion 23 of tubular body 20, for example by an inner ring projection 36 of rotatable actuation cylinder 230 and by a lock ring, in the same way as shown in Fig. 19 for endourethral sphincter 101. Also in this case, since upper portion 21 of tubular body 20 cannot rotate about its axis 29, a rotation 68’, 68” of rotatable actuation cylinder 230 causes a twisting of tubular body 20.

[0092] Motor 260 comprises a stator 250 coaxially and integrally mounted to container 10, and a rotor 251 rotatably arranged within stator 250 and integrally connected with actuation cylinder 230, so that a rotation of rotor 251 causes rotatable actuation cylinder 230 to perform a rotational movement 68’, 68” and tubular body 20 to twist, accordingly.

[0093] In an exemplary embodiment, rotor 251 comprises a ring portion 261 having a hollow cylindrical cross section equipped with a connection surface 262 to connect actuation cylinder 230, which can be a front ring surface or a side cylindrical surface of ring portion 261. Rotor 251 also comprises an induction diametrical portion 263 arranged along a diameter in ring portion 261 , and preferably comprising an extension 264 that extends along the axis of stator 250.

[0094] Figs. 39 and 40 are cross sectional views, obtained on the plane E-E indicated in Fig. 38, of stator 250 and of rotor 251 , in which the latter is manufactured according to two different exemplary embodiments. In both these exemplary embodiments, induction diametrical portion 263 includes an actuation magnet 266 having a first pole, in the case shown the North pole, facing an inner surface of stator 250. In a first exemplary embodiment, shown in Fig. 39, actuation magnet 266 extends along the whole induction diametrical portion 263, and has also the second pole, in this case the South pole, facing an inner surface of stator 250, whereas in a second exemplary embodiment, shown in Fig. 40, actuation magnet 266 is located in an end portion of induction diametrical portion 263.

[0095] In both the exemplary embodiments of Figs. 39 and 40, stator 250 comprises two stabilization magnets 281 and 282 angularly spaced apart from each other by a predetermined angle b having a vertex on the axis 259 of the stator. Each of stabilization magnets 281 and 282 is arranged with its own pole having a name opposite to the first pole of actuation magnet 266, i.e., in this case, the South pole, oriented inwards of stator 250, and with the other pole, in this case the North pole, oriented outwards of stator 250. This way, the angular positions of rotor 251 in which the North pole of actuation magnet 266 faces the South pole of stabilization magnet 281 (Figs. 39,40,44) or the South pole of stabilization magnet 282 (Fig. 46) are stable equilibrium positions for rotor 251.

[0096] Stator 250 has also a plurality of manoeuvre electromagnets 291 ,292,293,294 embedded therein, for instance a plurality of windings 291 ,292,293,294 of coils of an electrically conductive material preferably arranged in planes tangent to respective cylindrical surfaces 258 coaxial to stator 250. Moreover, manoeuvre electromagnets 291 ,292,293,294 are arranged so that the first pole of actuation magnet 266 faces one of manoeuvre electromagnets 291 ,292,293,294, when the rotor is in a respective angular position. This way, by feeding a predetermined current to each winding, a magnetic field is created whose magnetic induction vector, inside and at the outlet of each winding, is radially arranged and is radially oriented in the same way as the magnetic induction vector of the field produced by the stabilization magnets 281 and 282.

[0097] Control unit 290 is configured to selectively and consecutively supply an electric current to manoeuvre electromagnets 291 ,292,293,294, in this order or in the opposite order, by feeding means such as wires, a single connection portion 295 of which is shown. More in detail, control unit 290 is configured to supply currents of such an intensity that the magnetic field produced by electromagnets 291 ,292,293, i.e. up to the first electromagnet that is arranged beyond the centre of angle b, starting from a predetermined stabilization magnet 281 or 282, in this case from stabilization magnet 281 , and of such an intensity that this magnetic field can prevail over the magnetic field product by that stabilization magnet.

[0098] Lower portion 23 of tubular body 20 is connected to actuation cylinder

230 in such a way that, when the North pole of actuation magnet 266 is facing the South pole of stabilization magnet 281 , i.e. it is in the position of Fig. 39 or of Fig. 40, tubular body 20 is in the closed configuration, whereas, when the North pole of actuation magnet 266 is facing the South pole of stabilization magnet 282, tubular body 20 is in the open configuration, or vice-versa. Control unit 290 comprises a battery, not shown, for feeding the coils of stator 250.

[0099] Still with reference to Fig. 37, control unit 290 can have outwards radially protruding lock teeth 253 at an own end, said teeth configured to engage with lock channels 14 provided at the end of container 10, in order to fasten control unit 290 to container 10.

[0100] The operation of endourethral sphincter 103 is described with reference to Figs. 41 , 42 and 43, which are side views of endourethral sphincter 103 in which container 10 is removed, in open, partially open and closed configurations, respectively, and with reference to Figs. 44, 45 and 46, which are cross sectional views of device 103 as shown in Figs. 41 , 42 and 43, respectively. In order to move endourethral sphincter 103 from the open configuration (Figs. 41 ,44) to the closed configuration (Figs. 43,46), a remote control 296 is used to send an opening wireless signal 297 to control unit 290. According to this signal, control unit 290 is configured to operate in turn manoeuvre electromagnets 291 ,292,293,294, in this order, so as to subsequently generate magnetic fields whose magnetic induction vector, at the outlet of each winding, is arranged to cause rotor 251 to rotate from the open position of Fig. 44 to the closed position of Fig. 46. Similarly, in order to move endourethral sphincter 103 from the closed configuration (Figs. 43,46) back to the open configuration (Figs. 41 ,44), remote control 296 is used to send a closing wireless signal 297 to control unit 290. According to this signal, control unit 290 is configured to operate in turn manoeuvre electromagnets 294,293,292,291 , in this order, so as to subsequently generate magnetic fields whose magnetic induction vector 299, at the outlet of each winding, is arranged to cause rotor 251 to rotate from the closed position of Fig. 46 to the open position of Fig. 44.

[0101] The foregoing description of specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications such specific embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the embodiments exemplified. The means and the materials to put into practice the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.

Claims

1. An endourethral artificial sphincter (100,101 ,1 10,102,103) comprising:

a container (10) having a first longitudinal axis (19), said container (10) configured to be blocked within a patient’s urethra (4); a torsionally compliant tubular body (20) fixedly arranged within said container (10) with an own second longitudinal axis (29) parallel to said first longitudinal axis (19), and comprising:

a first end portion and a second end portion (21 ,23), said first end portion (21 ) integral to said container (10);

a torsionally compliant central portion (22) configured for an opening/closing torsional deformation (8,9) about said second longitudinal axis (29),

wherein said torsionally compliant tubular body (20) is configured to reversibly move between:

an open configuration (A), in which said torsionally compliant central portion (22) defines a passageway (24) in said torsionally compliant tubular body (20) along said second longitudinal axis (29), and

- a closed configuration (C), in which inner walls of said torsionally compliant central portion (22) are in contact with one another so as to completely block said passageway (24) in at least one part of said central portion (22),

said endourethral artificial sphincter (100,101 ,1 10,102,103) also comprising:

a rotatable actuation cylinder (30,130,230), rotatably arranged within said container (10) about said first longitudinal axis (19), wherein said second end portion (23) is integrally connected to said rotatable actuation cylinder (30,130,230),

characterized by a magnetic actuation unit (60,166,260) comprising an actuation magnet (66,166,266) movably arranged within said container (10), said magnetic actuation unit (60,166,260) connected to said rotatable actuation cylinder (30,130,230) in such a way that a movement (67’, 67”) of said magnetic actuation unit (60,166,260) induced by a manoeuvre magnet (90,190,291 ,292,293,294) positioned at a predetermined distance from said actuation magnet (66,166,266) causes an integral rotation (68’, 68”) of said rotatable actuation cylinder (30,130,230) and of said second end portion (23), thus causing said torsional deformation (8,9) of said central portion (22),

wherein said movement is selected from the group consisting of:

a closing movement (67’), wherein said rotation (68’) causes said closing torsional deformation (8);

- an opening movement (67”), wherein said rotation (68”) causes said opening torsional deformation (9).

2 . An endourethral artificial sphincter (101 ,1 10) according to claim 1 , wherein said magnetic actuation unit is a slidable magnetic actuation unit (60), wherein said closing/opening movement is a closing/opening translation movement (67’, 67”), wherein said endourethral artificial sphincter

(101 ,1 10) comprises:

an actuation magnet (66) having its poles spaced apart along an own first magnetic axis (169), and arranged with said first magnetic axis (169) parallel to said first longitudinal axis (19) of said container (10); - at least one outer radial protrusion (62),

wherein:

said structure (100) comprises a hollow cylindrical guide element (50) arranged within and integral to said container (10), said hollow cylindrical guide element (50) having at least one first channel (56) having a helical portion (51 );

said rotatable actuation cylinder (30) comprises a channelled part (35) configured to telescopically engage with said guide element (50) at said at least one first channel (56);

said channelled part (35) has at least one longitudinal second channel (31 );

said at least one outer radial protrusion (62) engages with said at least one first channel (56) and with said at least one second channel (31 ); such that said closing/opening translation movement (67767”) of said magnetic actuation unit (60) brings said at least one outer radial protrusion from an open position (A) to a closed position (C) / vice-versa along said helical portion (51 ) of said at least one first channel (56) and causes said integral rotation (68768”) of said second end portion (23) and of said rotatable actuation cylinder (30).

3. An endourethral artificial sphincter (101 ,1 10) according to claim 2, wherein said at least one first channel (56) comprises a linear longitudinal end portion (52) adjacent to said closed position (C).

4 . An endourethral artificial sphincter (101 ,110) according to claim 2, comprising:

an elongated resilient element (70) having a first end integral to said container (10) and a second end, opposite to said first end, arranged in contact with said actuation magnet (66), so that said slidable magnetic actuation unit (60) receives a resilient force (F_e) responsive to its own position along said container (10).

5. An endourethral artificial sphincter (101 ,1 10) according to claim 2, wherein said resilient element (70) comprises a cylindrical helical spring (70).

6. An endourethral artificial sphincter (1 10) according to claim 4, wherein said resilient element (70) is arranged so that said resilient force (F_e) exerted on said slidable magnetic actuation unit (60) is oriented so as to resist said opening translation movement (67”) of said slidable magnetic actuation unit (60).

7 . An endourethral artificial sphincter (101 ) according to claim 4, comprising:

a stabilization magnet (80) having its poles spaced apart along an own second magnetic axis (189), said stabilization magnet fixedly arranged with respect to said container (10) with said second magnetic axis (189) parallel to said first longitudinal axis (19) of said container (10), with said poles oriented so as to apply a magnetic force (Fm) on said actuation magnet (66), said magnetic force having a direction opposite to said resilient force (F_e), wherein said resilient element (70) and said stabilization magnet (80) are selected in such a way that:

said magnetic force (F_m) has an intensity higher than said resilient force (F_e) when said slidable magnetic actuation unit (60) is located within a predetermined equilibrium distance (d) from said stabilization magnet (80), and

said magnetic force (F_m) has an intensity lower than said resilient force (F_e) when said slidable magnetic actuation unit (60) is located beyond said equilibrium distance (d) from said stabilization magnet (80),

such that, by arranging said slidable magnetic actuation unit (60) within/beyond said equilibrium distance (d) with respect to said stabilization magnet (80), said slidable magnetic actuation unit (60), through said rotatable actuation cylinder (30) maintains/brings said torsionally compliant tubular body (20) in said closed (C) / open (A) configuration.

8. An endourethral artificial sphincter (101 ) according to claim 7, wherein said stabilization magnet (80) has the shape of a cylindrical annulus, and has said own second magnetic axis (189) coincident with the longitudinal axis of said cylindrical annulus.

9. An endourethral artificial sphincter (101 ) according to claim 8, wherein said actuation magnet (66) is coaxially mounted to said container (10).

10. An endourethral artificial sphincter (101 ) according to claim 7, wherein:

said resilient element (70) and said stabilization magnet (80) are arranged at one end portion of said container (10) opposite to said torsionally compliant tubular body (20) with respect to said guide element (50);

said resilient element (70) is mounted so as to be compressed when said slidable magnetic actuation unit (60) is in a position corresponding to said closed configuration (1 10) of said torsionally compliant tubular body (20);

said stabilization magnet (80) is arranged with said second magnetic axis oriented in the same way as said first magnetic axis of said slidable actuation magnet (66), so that said magnetic force (F_m) is a magnetic attractive force directed towards said stabilization magnet (80).

dourethral artificial sphincter (102) according to claim 1 , wherein: said magnetic actuation unit is a magnetic rotatable actuation unit and said closing/opening movement is an opening/closing rotation (67’, 67”);

said magnetic rotatable actuation unit comprises an actuation magnet (166) having its poles spaced apart along an own first magnetic axis (169) oriented from the South pole to the North pole of said actuation magnet (166);

said actuation magnet (166) is integrally mounted to said rotatable actuation cylinder (130) with said first magnetic axis (169) transversally arranged with respect to said first longitudinal axis (19) of said container (10);

said endourethral sphincter (102) also comprises:

a stabilization magnet (180) having its poles spaced apart along an own second magnetic axis (189) oriented from the South pole to the North pole of said stabilization magnet (180), and connected to said container (10) with said second magnetic axis (189) transversally arranged with respect to said first longitudinal axis (19) of said container (10), said stabilization magnet (180) arranged with an own reference pole (188) in an angular reference position of said container (10), so as to apply a magnetic moment (Mm) on said actuation cylinder (130), through said actuation magnet (166), said magnetic moment responsive to the direction of said first magnetic axis (169) of said actuation magnet (166) with respect to said second magnetic axis (189) of said stabilization magnet (180);

two abutment elements (17,18) integral to said container (10) arranged at predetermined respective abutment angles (qiz,qib) from said angular reference position;

an abutment member (139) peripherally connected to said actuation cylinder (130) at a predetermined abutment angle with respect to the pole (168) of said actuation magnet (166) having a name opposite to said reference pole (188) of said stabilization magnet (180), said abutment member (139) arranged to abut against said two abutment elements (17,18); said lower portion (23) of said tubular body (20) is connected to said actuation cylinder (130) in such a way that, when said abutment member (139) is arranged in a first abutment position against a first abutment element (17) of said abutment elements (17,18), said tubular body (20) is in said closed configuration (C), whereas, when said abutment member (139) is arranged in a second abutment position against a second abutment element (18) of said abutment elements (17,18), said tubular body (20) is in said open configuration (A),

in such a way that, by causing said rotatable actuation cylinder (130) to carry out a rotation by displacing said abutment member (139) from said first abutment position or from said second abutment position, said magnetic moment (M_m) can return said rotatable actuation cylinder (130) back to said first or back to said second abutment position, respectively, thus bringing said tubular body (20) back to said closed configuration (C) or back to said open configuration (A), respectively, or can attract said rotatable actuation cylinder (130) to said second abutment position or to said first abutment position, respectively, bringing said tubular body (20) to said open configuration (A) or to said closed configuration (C), respectively, according to whether, by said rotation, said second magnetic axis (189) of said actuation magnet (166) is brought beyond or is not brought beyond an angular position (E-i) wherein said second magnetic axis (189) has an orientation opposite to said first magnetic axis (169).

12 An endourethral artificial sphincter (102) according to claim 1 1 , wherein said first magnetic axis (169) and said second magnetic axis (189) are perpendicularly arranged with respect to said first longitudinal axis (19) of said container (10).

13. An endourethral artificial sphincter (102) according to claim 1 1 , wherein said abutment angles (qiz,qib) are equal to each other.

14. An endourethral artificial sphincter (102) according to claim 1 1 , wherein said abutment member (139) is arranged at said pole (168) having a name opposite to said reference pole (188).

15. An endourethral artificial sphincter (103) according to claim 1 , wherein:

said magnetic actuation unit comprises a motor (260) comprising: a stator (250) co-axial and integral to said container (10);

a rotor (251 ) rotatably arranged within said stator (250) and integrally connected with said actuation cylinder (230), said rotor (251 ) comprises an actuation magnet (266) having its poles spaced apart along an own first magnetic axis (269) radially arranged with respect to said stator (250),

said stator (250) comprises:

two stabilization magnets (281 ,282) angularly spaced apart from each other by a predetermined angle (b) having a vertex on said first longitudinal axis (19), said stabilization magnets (281 ,282) having their poles spaced apart along respective seconds magnetic axes (289), radially oriented with respect to said stator (250) and having the same direction as said first magnetic axis (269);

a plurality of manoeuvre electromagnets (291 ,292,293,294) arranged so that said first magnetic axis (269) is substantially aligned with said winding axes when said rotor (251 ) is in respective angular positions;

said lower portion (23) of said tubular body (20) is connected to said actuation cylinder (130) in such a way that, when said actuation magnet (266) is facing a first stabilization magnet (281 ) of said two stabilization magnets (281 ,282), said tubular body (20) is in said closed configuration (C), whereas, when said actuation magnet (266) is facing a second stabilization magnet (282) of said two stabilization magnets (281 ,282), said tubular body (20) is in said open configuration (A),

said endourethral sphincter (103) comprises a control unit (290) configured to selectively and consecutively supply a manoeuvre electric current to said manoeuvre electromagnets (291 ,292,293,294), said manoeuvre electric current having an intensity selected in such a way that said rotor (251 ) rotates, bringing said actuation magnet (266) to consecutively face said manoeuvre electromagnets (291 ,292,293,294),

such that, by selectively and consecutively supplying said manoeuvre electric current to said manoeuvre electromagnets (291 ,292,293,294), said rotor (251 ) rotates, causing said actuation magnet (266) to move from a position facing said first stabilization magnet (281 ) to a position facing said second stabilization magnet (282), or vice-versa, and bringing said tubular body (20) from said closed configuration (C) to said open configuration (A), or vice-versa, respectively.

16. An endourethral artificial sphincter (103) according to claim 15, wherein said plurality of manoeuvre electromagnets (291 ,292,293,294) comprises a plurality of windings (291 ,292,293,294) of coils of an electrically conductive material transversally arranged, in particular perpendicularly arranged, with respect to respective winding axes radially arranged with respect to said stator (250).

17 . An endourethral artificial sphincter (100,101 ,1 10,102,103) according to claim 1 , comprising a plurality of flexible longitudinal walls (25) arranged within said central portion (22) of said torsionally compliant tubular body (20), and said passageway is a multiple passageway (24) defined by said inner walls comprising walls of said flexible longitudinal walls (25) and walls of said central portion (22),

wherein said walls of said flexible longitudinal walls (25) are arranged to move towards/away from each other in said opening/closing torsional deformation (8,9) of said central portion (22) in such a way that, in said closed configuration (C), said flexible longitudinal walls (25) are in contact with one another so as to completely block said multiple passageway (24) in said longitudinal portion of said central portion (22).

is . An endourethral artificial sphincter (100,101 ,1 10,102,103) according to claim 17, wherein said flexible longitudinal walls are radial walls converging to said longitudinal axis (29) of said torsionally compliant tubular body (20).