MEDICAL DEVICE FOR LOCKING OFF A BODY CHANNEL

Description

[0001] The invention relates to a medical device for sealing off a body canal, comprising a band section that can be placed around the body tissue surrounding the body canal and can be closed to form a ring enclosing an opening for the body tissue, and which has a hollow chamber that forms part of a receiving space of the device for receiving working fluid, and a pump unit for conveying the working fluid, wherein the opening can be reduced in size by introducing the working fluid into the hollow chamber, wherein the device further comprises an expansion body with an expansion chamber, and the expansion chamber can be enlarged by introducing an auxiliary fluid separate from the working fluid into the expansion chamber.

[0002] Medical devices for closing off a body canal are used, among other things, as artificial (sphincter) muscles to support or replace weakened natural muscles in the human or animal body. Examples of applications for such devices include anal slings for closing an anus (which may be artificial) and artificial sphincters for treating incontinence by closing the urethra. Other applications include, for example, slings for closing a bile duct. The sling component of such medical devices is also called a cuff or artificial sphincter.

[0003] The hollow chamber of the band section can be emptied by the user as needed to increase the cross-sectional area of ​​the opening and allow substances and / or fluids contained in the body canal to pass through. For example, when used as an artificial urethral sphincter, the body canal is often automatically closed afterward by pumping working fluid back into the hollow chamber of the band section (possibly via a throttle valve). In such cases, a pump for pumping working fluid is typically implanted in the scrotum for male patients. Pumping working fluid out of the hollow chamber can then be achieved by pressing on a flexible part of the pump. Pumping working fluid back into the hollow chamber can be accomplished by a spring-loaded element of the pump.The opening of the medical device can often be reduced again by a conscious action of the user, i.e. by manually operating the pump.

[0004] Several embodiments of medical devices in the form of urethral sphincters are known from US Patent 2014 / 0364686 A1, which have a band section with two hollow chambers. An intermediate wall separating the two hollow chambers has a valve that allows fluid exchange between the chambers. A pump can be used to transfer the fluid from one of the hollow chambers to the other to open the body canal. Further examples of medical devices are described in US Patent 2010 / 0211175 A1 and US Patent 2009 / 0248109 A1.

[0005] A problem with medical devices used to narrow or close off a body channel is that the pressure exerted by the device on the body tissue can cause erosion. Therefore, the pressure of the working fluid in the hollow chamber is generally chosen to minimize tissue erosion while still ensuring reliable closure of the body channel.

[0006] When the abdominal muscles tense up, as usually happens involuntarily when climbing stairs, lifting heavy objects, sneezing, coughing, or laughing, there is a brief increase in intra-abdominal (within the abdominal cavity) pressure. These brief pressure peaks affect the internal (hollow) organs located in the abdominal cavity, such as the bladder and intestines.

[0007] This increases the pressure in the (hollow) organs, which can lead to the leakage of substances and / or fluid through the section of the body canal sealed off by the sling. This type of incontinence is also known as stress incontinence.

[0008] US Patent 5,478,305 A describes a medical device for treating urinary or fecal incontinence. The band component, referred to in this patent as the cuff, is made of silicone. Filling the cuff with working fluid increases the pressure within the cuff's cavity. This pressure causes an inner section of the cuff to shift toward its longitudinal axis, thus sealing the body canal. A flexible silicone balloon (the "stress balloon") is positioned between two sections of a connecting tube that fluid-conducts a pump to the cuff. The stress balloon's cavity is filled with working fluid. A brief increase in intra-body pressure causes the stress balloon's cavity to collapse, displacing working fluid into the cuff. This temporary increase in working fluid pressure allows the body canal to remain sealed, even during a stressful event, preventing leakage.If the intra-body pressure subsequently decreases, the volume of the stress balloon's cavity increases and the pressure of the working fluid decreases, causing working fluid to flow out of the cuff. If the pressure of the working fluid in the cuff is increased to close the body canal, the balloon's volume also increases, requiring a correspondingly larger volume of fluid to be moved by the pump.

[0009] US Patent 4,784,660 A describes a medical device of the type mentioned above, comprising a pump unit with a working fluid chamber and an auxiliary fluid chamber. The working fluid chamber can be filled with a working fluid, and the auxiliary fluid chamber is filled with an auxiliary fluid. Adding auxiliary fluid to the auxiliary fluid chamber increases the volume of the auxiliary fluid chamber while simultaneously decreasing the volume of the working fluid chamber, thereby increasing the pressure of the working fluid. This allows additional force to be applied to the urethra, which is guided by a belt section of the medical device that can be filled with the working fluid. A similar medical device is also described in US Patent 4,721,509 A.

[0010] The object of the invention is to provide an advantageous device of the type mentioned above, which can be used to treat stress incontinence.

[0011] According to the invention, this is achieved by a device having the features of claim 1.

[0012] The device according to the invention comprises an expansion body with an expansion chamber, the expansion body being arranged on the side of the belt section facing the through-opening. The expansion chamber can be enlarged by introducing the auxiliary fluid, which is separate from the working fluid, into the expansion chamber. The expansion chamber can thus be filled with the auxiliary fluid independently of the working fluid.

[0013] When a stressful event occurs, for example, caused by an increase in intra-body pressure during a coughing fit, the expansion chamber enlarges, thereby applying additional force to the body tissue passing through the opening. The body channel is thus reliably sealed even during a stressful event. During a stressful event, the intra-body pressure (= ambient pressure) is always higher than atmospheric pressure.

[0014] The auxiliary fluid is advantageously completely separated from the working fluid, i.e., no fluid exchange takes place between the auxiliary fluid and the working fluid.

[0015] Providing two independent fluid systems allows for additional design options for the medical facility.

[0016] The increase in volume of the expansion body by filling the expansion chamber with auxiliary fluid is achieved in particular by stretching or unfolding the expansion body.

[0017] The expansion element can be designed to be elastically expandable. In other embodiments, however, the expansion element can also be made of a material that is at least substantially inextensible. For example, a bellows sealed at both ends could be provided, which expands when auxiliary fluid is poured into the expansion chamber. It is also conceivable and possible that the volume change of the expansion element is achieved by moving at least one movable wall of the expansion element. The movable wall could, for example, be a piston that can be moved by pouring auxiliary fluid into the expansion chamber.

[0018] In this document, the term "receiving space for the working fluid" refers to the entire internal cavity of the device in which working fluid is located during the operation of the device.

[0019] The pump unit advantageously includes a pumping section that has an interior space for receiving working fluid, the volume of which can be changed by means of a drive.

[0020] The pump unit allows working fluid to be introduced into the hollow chamber of the belt section. By shifting an inner section of the belt section facing the through-opening towards a longitudinal center axis of the through-opening, the body channel can be sealed off.

[0021] In the embodiment according to the invention, the expansion body is arranged on the side of the belt part facing the passage opening, i.e., on the inner section of the belt part, and filling the expansion chamber with auxiliary fluid has a direct compressive effect on the body tissue surrounding the body canal due to the resulting increase in the volume of the expansion chamber, in order to ensure reliable sealing of the body canal during a stress event.

[0022] The expansion chamber could, in principle, be filled using a sensor-controlled auxiliary fluid pump, whereby a pressure increase inside the chamber could be detected by a pressure sensor, triggering the activation of the auxiliary fluid pump accordingly. However, in a preferred embodiment, the device includes an auxiliary fluid reservoir with a storage chamber for the auxiliary fluid, the volume of which can be varied depending on the ambient pressure. The auxiliary fluid reservoir is connected to the expansion chamber via an auxiliary fluid line.

[0023] The auxiliary fluid reservoir is advantageously implantable within the body, particularly in the abdominal cavity, where the intrabody pressure acts upon it. Ideally, the pressure of the auxiliary fluid then corresponds to the intrabody pressure. When abdominal muscles contract during a stressful event, the volume of the reservoir's storage chamber changes in accordance with the intrabody pressure. During this process, auxiliary fluid is expelled from the storage chamber and conveyed through the auxiliary fluid line into the expansion chamber. Therefore, no additional pump is required to transport the auxiliary fluid.

[0024] Advantageously, the auxiliary fluid container has a flexible wall that delimits the storage chamber. In this context, "flexible" refers to a bendable wall, which, however, need not necessarily be extensible. Preferably, the flexible wall is at least substantially inextensible. When the auxiliary fluid container is filled, no material expansion occurs, meaning that the volume of the storage chamber can only be increased by unfolding the flexible wall. Advantageously, the volume of the storage chamber is limited to a maximum storage volume.

[0025] In an advantageous embodiment, the flexible wall bounding the storage chamber is designed to be flexibly deformable. This means that the wall does not return to its previous shape on its own (i.e., without the application of an external force). With a flexibly deformable wall, the auxiliary fluid container could also be described as shape-unstable.

[0026] In another embodiment, for example, a bellows sealed on both sides could be provided as an auxiliary fluid container, whereby the volume of the storage chamber can be increased by expanding the bellows.

[0027] In principle, it would also be conceivable that the auxiliary fluid container has at least one movable wall, e.g. in the form of a piston.

[0028] Advantageously, the volume of the expansion chamber is designed to be essentially zero when the working fluid is under a higher pressure than the auxiliary fluid. If the volume of the expansion chamber is essentially zero or relatively small in the release state, then little or no auxiliary fluid needs to be transferred from the expansion chamber to the auxiliary fluid reservoir when the belt section is moved from the release to the shut-off state. This minimizes the amount of working fluid that needs to be transferred. If the medical device has an electrically operated pump, this can result in energy savings.

[0029] Further advantages and details of the invention are explained below with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a device designed as an artificial urethral sphincter, not according to the invention, in a release state of the band part in which the ureter is open; Fig. 2 an analogous representation Fig. 1 in a closed state of the ligament segment in which the ureter is closed; Fig. 3 an analogous representation Fig. 1 in a stress state of the ligament segment, in which an additional force is exerted on the ureter; Fig. 4 und 5 Oblique views of the free, i.e., non-implanted, part of the device in an open and closed state, corresponding to the release state; Fig. 6 a longitudinal central section (parallel to and passing through the longitudinal central axis of the passage opening) through the band section in the state according to Fig. 5 ; Fig. 7 a longitudinal mid-section analogous Fig. 6 , but in the locked state of the belt section; Fig. 8 a schematic representation of an embodiment of an artificial urethral sphincter according to the invention in a closed state of the band part in which the ureter is closed; Fig. 9 an analogous representation Fig. 8 in a stress state of the ligament segment, in which an additional force is exerted on the ureter; Fig. 10 a schematic representation of a variant of the band part according to the embodiment of the invention in a closed state of the band part in which the ureter is closed, and Fig. 11 an analogous representation Fig. 10 in a state of stress of the ligament segment, in which an additional force is exerted on the ureter.

[0030] A band section 1 of the medical device can be placed in a ring shape around the body tissue 2 surrounding the body canal, here the urethra. The band section 1 has a hollow chamber 3 that extends in the direction of the longitudinal extent of the band section 1, in the exemplary embodiments essentially over the entire length of the band section 1. The band section 1 is thus tubular in shape with closed ends at both ends.

[0031] At the two ends of the strap section 1, a first and a second locking part 6, 7 are arranged. The first locking part 6 has an insertion opening 6a into which a tongue 7a of the second locking part 7 can be inserted and locked.

[0032] The closure parts 6, 7 thus form a closure with which the band part 1 can be closed to form a ring, in particular a circular ring, cf. Fig. 5 . In the closed state, the band part 1 encloses an opening 4 for the body tissue 2 surrounding the body canal.

[0033] The cavity 3 contains a working fluid, in particular a liquid, e.g., a saline solution. The size of the opening 4 depends on the amount of working fluid in the cavity 3. By introducing working fluid into the cavity 3, the opening 4 can be reduced in size. This is achieved by displacing a flexible inner section 1a of the belt section 1, which is adjacent to the longitudinal axis 5 of the opening 4, in the direction of the longitudinal axis 5, as is known. By removing working fluid from the cavity 3, the opening 4 can be enlarged again.

[0034] Fig. 6 shows the state in which the through-hole 4 is largest (where the pressure of the working fluid in the hollow chamber 3 corresponds to the ambient pressure). Fig. 7 shows a state filled with the working fluid, in particular the state filled to the maximum with working fluid (where the pressure of the working fluid in the cavity 3 is above the ambient pressure). In Fig. 7 Folds, such as those that would occur particularly if the ligament section were not wrapped around the ureter, are not shown. A dorsal section 1b of the ligament section 1, located away from the longitudinal central axis 5, can be made rigid relative to the inner section 1a, particularly by means of a reinforcing layer, thereby largely preventing deformation of the dorsal section 1b.

[0035] In the closed state of the band section 1 placed around the body canal, it can therefore enter a release state in which the body canal is open (cf. Fig. 1 ), and a closed state in which the body channel is closed (cf. Fig. 2 ). In the release state, the pressure of the working fluid in the cavity 3 can, for example, correspond to atmospheric pressure. In the sealed state, the cavity 3 is filled with such a quantity of working fluid that the body channel is closed.

[0036] Different modifications to the design of the strap section are conceivable and possible; for example, it would be possible to omit special closure parts attached to strap section 1 altogether and to sew the two ends of the strap section together.

[0037] The first part of the band can be made of silicone in the usual way. Other biocompatible materials can also be used in principle.

[0038] In the exemplary embodiment, a connecting piece 8 is integrally formed on one of the closure parts, the cavity of which is connected to the hollow chamber 3 via a channel running through the closure part. Such a connecting piece could also be provided at another location on the belt section. A working fluid line 9, designed as a hose, is connected to the connecting piece 8.

[0039] The belt section 1 is connected via the channel of the working fluid line 9 to a pump section 11 of a pump unit 10 which is geographically separate from the belt section 1, cf. Fig. 1 bis 3 The amount of working fluid in the hollow chamber 3 of the belt section 1 can be changed by means of the pump unit 10.

[0040] A receiving chamber for the working fluid (= working fluid receiving chamber) of the medical device comprises the entire continuous internal cavity of the device, which contains working fluid during operation. The hollow chamber 3 of the belt section 1, the channel of the closure part of the belt section 1 running through the closure part, and the channel of the working fluid line each form part of the receiving chamber for the working fluid. In the exemplary embodiment, the pump section 11 of the pump unit 10 has an interior space 12 filled with working fluid, which also forms part of the receiving chamber of the device.

[0041] A port 18 is provided in the conventional manner for filling the receiving chamber of the medical facility with working fluid. This can, for example, be connected to the pump unit 11 via a hose.

[0042] In the exemplary embodiments, the pump part 11 is formed by a bellows, which is closed by a bottom part 13 and a cover part, which represents an actuating element 14. An electric drive 15 acts on the actuating element 14 via a gearbox 16, for example a screw drive, to change the volume of the interior 12. The gearbox 16 is advantageously designed to be self-locking, so that a position of the actuating element 14, once set, is maintained without the supply of electrical energy to the drive 15.

[0043] In the exemplary embodiment, the pump part 11 thus simultaneously forms a reservoir for the working fluid, with which the hollow chamber 3 of the belt part 1 is filled to close the body channel. The pump part 11 could, for example, also be formed by a piston-cylinder unit, with the actuating element 14 being formed by the piston of this piston-cylinder unit.

[0044] The electric drive 15 is controlled by a control electronics unit 17 of the pump unit 10, which also includes a battery (not shown) for supplying the drive 15 with electrical current. The control electronics unit 17 is operated by the user via a suitable user interface (not shown). The user interface can be a control unit with corresponding switches, connected to the control electronics unit 17 either by cable or wirelessly.

[0045] The user interface can be located outside the body. Implantation of the user interface is conceivable and possible. Alternatively, a separate user interface could be omitted entirely, in which case at least one user-operated control element would have to be located on the pump unit 10. This element would have to be operable from outside the body.

[0046] The components of the pump unit 10 are arranged in a housing 19. The housing 19 is made of or encased in a biocompatible material.

[0047] The medical device further comprises an auxiliary fluid container 22 with a storage chamber 23 filled with auxiliary fluid during operation of the device. The auxiliary fluid container 22 is advantageously implanted in the body. The auxiliary fluid container 22 has a flexible wall that delimits the storage chamber 23. This wall can be designed to be at least substantially inextensible.

[0048] The material property of the wall of the auxiliary fluid container 22 is described as "essentially inextensible," whereby the volume of the storage chamber 23 increases by less than 10%, preferably less than 5%, when the pressure of the auxiliary fluid in the auxiliary fluid container 22 increases from a maximally expanded state by 0.1 bar. The auxiliary fluid container 22 could have a reinforcement which advantageously has a modulus of elasticity of at least 1000 N / mm², preferably at least 5000 N / mm².

[0049] In the exemplary embodiment, the wall of the auxiliary fluid container 22 is also designed to be flexible, meaning that the wall does not automatically return to its previous shape. The wall of the auxiliary fluid container 22 could, for example, be formed from a plastic film. The auxiliary fluid container 22 according to the illustrated exemplary embodiments is thus advantageously foldable, whereby the volume of the storage chamber 23 can be changed by folding or unfolding the auxiliary fluid container 22 depending on the ambient pressure (= internal pressure).

[0050] Ideally, the pressure of the auxiliary fluid during operation of the device corresponds to the ambient pressure (= intrabody pressure).

[0051] The wall of the auxiliary fluid container 22 is preferably made of a biocompatible material, e.g., polyamide or silicone, or is encased in such a material. Any reinforcement present can be embedded in this material.

[0052] The storage chamber 23 of the auxiliary fluid container 22 is fluidly connected to an expansion chamber 21 of an expansion body 20 via an auxiliary fluid line 24. The storage chamber 23, the inner channel of the auxiliary fluid line 24, and the expansion chamber 21 each form part of an auxiliary fluid receiving chamber of the medical device. The auxiliary fluid receiving chamber refers to the entire internal cavity of the device in which auxiliary fluid is located during operation.

[0053] The auxiliary fluid, separate from the working fluid, could be introduced, for example, via a port (not shown) into the auxiliary fluid line 24 or directly into the storage chamber 23. The auxiliary fluid is preferably a liquid, e.g., a saline solution.

[0054] The expansion body 20 is in the Figuren 1 bis 7 The illustrated, non-inventive example of a medical device is arranged in the receiving chamber of the device filled with working fluid, namely in the interior 12 of the pump part 11.

[0055] The volume of the expansion chamber 21 can be increased by introducing auxiliary fluid into the expansion chamber 21 through unfolding or stretching of the expansion body 20. If the increase is achieved solely through unfolding, the expansion body 20 can be made of an inextensible material, thus limiting the maximum volume of the expansion chamber 21. Consequently, any pressure increase of the working fluid (as explained below) is limited by the volume of the expansion chamber 21. Alternatively, the volume of the expansion chamber 21 can be increased by using an elastically stretchable expansion body 20.

[0056] The expansion body 20 can also be designed to be flexible, i.e., the expansion body 20 is then shape-labile, as shown in the Fig. 1 und 2 as indicated.

[0057] At least in the Fig. 2 In the depicted sealed state of the belt section 1, the auxiliary fluid is under a lower pressure than the working fluid. The expansion chamber 21 of the expansion body 20 is preferably completely folded. Thus, there is at least substantially no auxiliary fluid in the expansion chamber 21. In other words, the auxiliary fluid is displaced from the expansion chamber 21 into the storage chamber 23 of the auxiliary fluid container 22 due to the higher pressure of the working fluid acting on the expansion body 20. The volume of the expansion chamber 21 is therefore at least substantially zero. This could, in principle, be different in a modified embodiment.

[0058] Also in Fig. 1 In the figure relating to the release state of belt section 1, the expansion chamber 21 is shown completely folded, i.e., with a volume of essentially zero. This is the case when the auxiliary fluid is under a lower pressure than the working fluid and / or when, at the same pressure (of the auxiliary fluid and the working fluid), the auxiliary fluid is displaced from the expansion chamber 21 by the elasticity of the expansion element 20. A certain residual volume of the expansion chamber 21 may also be present in the release state.

[0059] If the internal body pressure increases, for example due to a coughing fit, a force caused by the internal body pressure acts directly on the auxiliary fluid reservoir 22. When a force is exerted on the auxiliary fluid reservoir 22, the pressure of the auxiliary fluid increases accordingly. If the internal body pressure, and thus the pressure of the auxiliary fluid, is greater than the pressure of the working fluid, the auxiliary fluid reservoir 22 is compressed, and auxiliary fluid is displaced from the storage chamber 23 into the expansion chamber 21. If the expansion element 20 opposes the expansion of the expansion chamber 21 with an elastic restoring force, this force can also be overcome by the pressure of the auxiliary fluid (the expansion element 20 is therefore only expanded when the ambient pressure exceeds the pressure of the working fluid to such an extent that the elastic restoring force is also overcome by the pressure of the auxiliary fluid).The resulting increase in the volume of the expansion chamber 21 leads to an increase in the pressure in the interior 12 of the pump section 11. Working fluid is expelled from the interior 12 and introduced into the hollow chamber 3 of the belt section 1. The inner section 1a of the belt section 1 is displaced towards the longitudinal center axis 5, thereby applying an additional force to the body tissue 2 guided through the opening 4. This state of the belt section 1 is referred to in this document as the stress state of the belt section 1 and is described in . Fig. 3 depicted.

[0060] If, as a consequence, the internal pressure of the body and thus the pressure of the auxiliary fluid decreases again, so that the pressure of the auxiliary fluid is lower than the pressure of the working fluid (possibly including the elastic restoring force of the expansion body), the volume of the storage chamber 23 of the auxiliary fluid container 22 increases by absorbing auxiliary fluid discharged from the expansion chamber 21 of the expansion body 20. After the stress event, the belt section 1 is thus again in the closed state, cf. Fig. 2 .

[0061] If the body channel is to be opened from the closed state of the belt part 1, e.g. for draining urine, i.e. the belt part 1 is to enter the release state by displacing working fluid from the hollow chamber 3 into the interior 12 of the pump part 11 (see Fig. 1 When the belt section 1 is in its closed position and no stress event is occurring, the volume of the expansion chamber 21 remains essentially zero or relatively small. Therefore, when the belt section 1 is moved from the closed to the open position (and vice versa), little or no auxiliary fluid needs to be transferred from the expansion chamber 21 to the storage chamber 23 of the auxiliary fluid reservoir 22. This minimizes the amount of working fluid to be moved and reduces the associated energy expenditure for this transfer. Consequently, the interval for charging or replacing the battery of the control electronics 17 can be extended.

[0062] In the Fig. 8 and 9Figure 1 is an embodiment of a medical device according to the invention. The design of the pump unit 10 and the auxiliary fluid container 22 corresponds to that of the previously described example of a medical device, so that the explanations of the embodiment according to the invention mainly refer to the differences from the previously described example. Apart from the differences listed below, the explanations of the previously described example also apply to the embodiment according to the invention. Thus, the design of the [unclear text] is also [unclear text]. Fig. 8 and 9 Only schematically depicted closure parts 6, 7 of the band part 1 refer to the explanations of the previously explained example.

[0063] In the medical device according to the embodiment of the invention, the expansion body 20 is arranged on one side of the belt section 1 facing the through-opening 4, i.e., on the inner section 1a of the belt section 1. This is shown in the Fig. 8 and 9 schematically represented, wherein the expansion chamber 21 extends in the direction of the longitudinal extent of the belt part 1, essentially over the entire length of the belt part 1. The expansion body 20 is thus designed in a tube-like form in the embodiment according to the invention, with closed ends on both sides.

[0064] The expansion body 20 arranged on the band part 1 has, in the closed state of the band part 1, a substantially circumferential contact surface 20a for contact with the body tissue 2 with respect to the circumferential direction of the longitudinal central axis 5.

[0065] In the sealed state of the closed belt section 1, the hollow chamber 3 is filled with such a quantity of working fluid that the body channel is closed, cf. Fig. 8 .

[0066] When working fluid is drained, the belt section 1 assumes the release state (not shown separately) in which the body channel is open.

[0067] If the pressure inside the body (= intrabody pressure) increases, starting from the in Fig. 8 When the depicted sealing state of the band section 1 occurs during a stress event, this intra-body pressure acts on the auxiliary fluid reservoir 22 analogously to the previously explained example. If the intra-body pressure, and thus the pressure of the auxiliary fluid, is greater than the counter-pressure exerted by the body tissue 2 on the expansion body 20, the auxiliary fluid reservoir 22 is compressed, and auxiliary fluid is directed from the storage chamber 23 into the expansion chamber 21 of the expansion body 20. If the expansion body 20 opposes the expansion of the expansion chamber 21 with an elastic restoring force, this can also be overcome by the pressure of the auxiliary fluid. By increasing the volume of the expansion chamber 21, the expansion body 20 exerts a direct compressive effect on the body tissue 2 surrounding the body canal to ensure reliable sealing of the body canal during a stress event, cf. the illustration in Fig. 9 The depicted stress state of the ligament segment 1, in which an additional force is applied to the body tissue 2 guided through the opening 4. The body tissue 2 itself is in the Fig. 8 and 9 not shown.

[0068] Once the intrabody pressure returns to a baseline state, i.e., without a stress event occurring, the auxiliary fluid flows back from the expansion chamber 21 into the auxiliary fluid reservoir 22, cf. the one in Fig. 8 shown locking state of belt section 1.

[0069] In the embodiment according to the invention, the auxiliary fluid flows back into the auxiliary fluid container 22 by the action of the counter-pressure exerted by the body tissue 2 together with the pressure exerted on the expansion body 20 by the hollow chamber 3 filled with working fluid. If the expansion body 20 opposes the expansion of the expansion chamber 21 with an elastic restoring force, this can have a supporting effect on the backflow of the auxiliary fluid.

[0070] In the embodiment according to the invention, the expansion element 20 and the band section 1 can be formed in one piece. Advantageously, the expansion element 20 is designed to be elastically stretchable in this embodiment. In another embodiment, however, the expansion element 20 could also be designed to be essentially inextensible and / or flexible.

[0071] The belt part 1 and / or the expansion body 20 could(n) in the exemplary embodiment be made of a biocompatible material, e.g. silicone.

[0072] In the exemplary embodiment, a connection fitting (not shown) for connecting the belt section 1 to the auxiliary fluid line 24 is integrally formed on the closure part 7. The interior of the connection fitting is connected to the expansion chamber 21 via a channel running through the closure part 7. Such a connection fitting could also be provided at another location on the expansion body 20 or on the belt section 1.

[0073] In the Fig. 10 und 11 A variant of the band section 1 according to the second embodiment is shown, with particular attention paid below to the differences compared to the one described in the following. Fig. 8 and 9 Part 1 of the volume is discussed.

[0074] In the Fig. 10 und 11 In the modified form of the band section 1 shown, the expansion body 20 extends in the direction of the longitudinal extent of the band section 1 over approximately half the length of the band section 1. The passage opening 4 is located in the Fig. 10 In contrast to the second embodiment, the depicted closed state of the belt section 1 is not circular. The contact surface 20a of the expansion body 20 extends, in the closed state of the belt section 1, over 180° of the circumference of the passage opening 4 in a circumferential direction starting from the longitudinal center axis 5.

[0075] Otherwise, band part 1 behaves according to the description in Fig. 10 und 11 The modified form shown, when a stress event occurs, is analogous to band part 1 of the second embodiment of the medical facility, which is why reference is made to the corresponding explanations for the second embodiment.

[0076] Apart from the pump unit shown in the exemplary embodiments, the medical device could in principle also be used in combination with a pump unit that is well known in the prior art, for example, a manually operated one. legend Regarding the reference numbers:

[0077] 1 Belt section 1a Inner section 1b Back section 2 Body tissue 3 Hollow chamber 4 Passage opening 5 Longitudinal center axis 6 First closure part 6a Insertion opening 7 Second closure part 7a Tongue 8 Connection spigot 9 Working fluid line 10 Pump unit 11 Pump part 12 Interior 13 Base part 14 Actuator 15 Drive 16 Gearbox 17 Control electronics 18 Port 19 Housing 20 Expansion body 20a Mounting surface 21 Expansion chamber 22 Auxiliary fluid reservoir 23 Storage chamber 24 Auxiliary fluid line

Claims

1. Medical device for shutting off an anatomical channel, comprising - a band part (1) which can be placed around the body tissue (2) surrounding the anatomical channel and which can be closed to form a ring that encloses a through-opening (4) for the body tissue (2), and which has a hollow chamber (3) constituting a part of a receiving space of the device for receiving working fluid , and - a pump unit (10) which serves to convey the working fluid, wherein the through-opening (4) can be made smaller by introducing the working fluid into the hollow chamber (3), wherein the device moreover has an expansion body (20) with an expansion chamber (21), and the expansion chamber (21) can be made larger by introducing an auxiliary fluid, separate from the working fluid, into the expansion chamber (21), characterised in that the expansion body (20) is arranged at the band part(1), on a side of the band part (1) directed toward the through-opening (4), and in that the medical device is embodied to fill the auxiliary fluid into the expansion chamber and the resulting enlargement of the volume of the expansion chamber thereby acting directly compressing onto the body tissue surrounding the anatomical channel, in order to ensure a reliable shutting-off of the body channel during an increase in internal body pressure occurring in a stress event.

2. Medical device according to claim 1, characterized in that the device has an auxiliary fluid container (22) with a storage chamber (23) for the auxiliary fluid, the volume of which storage chamber (23) is variable depending on an ambient pressure, and the auxiliary fluid container (22) is connected to the expansion chamber (21) via an auxiliary fluid line (24).

3. Medical device according to claim 2, characterized in that the auxiliary fluid container (22) has a flexible wall delimiting the storage chamber (23).

4. Medical device according to claim 3, characterized m that the wall is substantially non-extensible.

5. Medical device according to claim 3 or 4, characterized in that the wall is pliable.

6. Medical device according to one of claims 1 through 5, characterized in that the pump unit (10) has a pump part (11) which has an interior (12) for receiving working fluid, wherein the volume of the interior (12) is variable by a drive (15).

7. Medical device according to one of claims 1 through 6, characterized in that the expansion body (20) arranged at the band part (I) has a bearing surface (20a) for bearing on the body tissue (2).

8. Medical device according to one of claims 1 through 7, characterized in that the volume of the expansion chamber (21) is at least substantially equal to zero when a working fluid is at a higher pressure compared to the pressure of the auxiliary fluid .

9. Medical device according to one of claims 2 through 8, characterized in that the pressure of the auxiliary fluid rises when a force is exerted on the auxiliary fluid container (22).