implantable medical devices

Abstract

The present invention relates to an implantable medical device (10) comprising a variable volume fluid reservoir (5) deformable under the influence of changes in atmospheric pressure, an inflatable element (3) in fluid communication with the reservoir (5), an actuator (8) adapted to selectively vary the volume of the reservoir (5), and a data processing / control unit (200) configured to direct the actuator (8) to selectively vary the volume of the reservoir (5), wherein the unit (200) is configured to perform at least one of the following steps when an estimated atmospheric pressure exceeds at least one atmospheric pressure threshold and / or when an estimated altitude exceeds at least one altitude threshold: a) commanding, by the unit (200), at least one drainage of fluid from the inflatable element (3) into the reservoir (5) by the actuator (8); and b) commanding, by the unit (200), at least one injection of fluid from the reservoir (5) into the inflatable element (3) by the actuator (8).

Description

[Technical Field]

[0001] The present invention relates to an implantable medical device that includes a variable volume fluid reservoir that is deformable under the influence of atmospheric pressure changes. [Background technology]

[0002] Medical devices may take the form of systems that can be implanted within the human or animal body, such as artificial urinary sphincters used to treat urinary incontinence, gastric bands or rings suitable for gastric restriction to treat obesity, and inflatable penile implants used in erectile prostheses, among others.

[0003] In a manner known per se, the implantable system may be hydraulically operated and may in particular consist of a variable volume fluid reservoir and an inflatable element containing a variable amount of fluid, the inflatable element being in fluid communication with the variable volume fluid reservoir and capable of transferring fluid from the reservoir to the inflatable element and vice versa.

[0004] In the case of an implantable occlusion system, such as an artificial urinary sphincter, the inflatable element is an inflatable occlusion cuff that can selectively occlude an anatomical conduit, such as the male urethra or the female bladder neck. Fluid can be transferred from a reservoir to the cuff to increase pressure on the conduit, and conversely, fluid can be transferred from the cuff to decrease pressure on the conduit. This allows the pressure on the occluded anatomical conduit to be increased or decreased depending on the amount of fluid in the cuff.

[0005] Elements of an implantable fluid system may deform in response to changes in atmospheric pressure (e.g., due to changes in altitude). For example, a reservoir of an implantable fluid system may include an elastically deformable portion that deforms in response to changes in atmospheric pressure. This deformation may result in uncontrolled fluid infusion or evacuation from the cuff, causing an increase or decrease in pressure within the cuff.

[0006] However, such pressure changes in the inflatable element should be avoided. In the case of an artificial urinary sphincter, excessive pressures are likely to damage the tissue in which the cuff is placed. Therefore, these overpressures must be compensated for to limit the risk of corresponding tissue damage. Summary of the Invention

[0007] One purpose of the present invention is to compensate for the effects of atmospheric pressure changes on implantable medical devices.

[0008] Thus, according to a first aspect, the present invention provides an implantable medical device comprising: a variable volume fluid reservoir deformable under the influence of atmospheric pressure changes; an inflatable element in fluid communication with the reservoir; an actuator adapted to selectively vary the volume of the fluid reservoir; and a data processing / control unit configured to control the selective variation of the volume of the fluid reservoir by the actuator, wherein the unit is configured to: a) controlling, by a data processing / control unit, at least one ejection of fluid from an inflatable element into a reservoir by an actuator; and b) the device is configured to perform at least one of the steps of controlling, by a data processing / control unit, at least one injection of fluid from the reservoir into the inflatable element by an actuator.

[0009] According to other advantageous and non-limiting features, the following features can be used alone or in combination:

[0010] The data processing / control unit performing step a) if the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold and the atmospheric pressure is lower than at least one atmospheric pressure threshold, or if the estimated altitude exceeds at least one altitude threshold and the estimated altitude is higher than at least one altitude threshold; and / or and configured to perform step b) if the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold and the atmospheric pressure is higher than the at least one atmospheric pressure threshold, or if the estimated altitude exceeds at least one altitude threshold and the estimated altitude is lower than the at least one altitude threshold.

[0011] The data processing / control unit is configured to perform, before step a) or b), a step a01) or b01) of calculating the amount of fluid to be withdrawn or injected.

[0012] The data processing / control unit is configured to perform a step a0) of estimating the atmospheric pressure based on at least one value of the fluid pressure in the reservoir.

[0013] The data processing / control unit is configured to calculate the amount of fluid to be withdrawn or injected depending on the atmospheric pressure range into which the estimated atmospheric pressure falls, with the atmospheric pressure threshold being the lower or upper limit value, and / or depending on the altitude range into which the estimated altitude falls, with the altitude threshold being the lower or upper limit value.

[0014] The estimated atmospheric pressure falls within one of a plurality of atmospheric pressure ranges and / or the estimated altitude falls within a new one of a plurality of altitude ranges, and the data processing / control unit is configured to calculate an amount of fluid to be withdrawn or injected depending on the atmospheric pressure range within which the estimated atmospheric pressure falls and / or depending on the atmospheric pressure range within which the estimated altitude falls.

[0015] The estimated atmospheric pressure is now included in one of two or more atmospheric pressure ranges, preferably three or more atmospheric pressure ranges, more preferably four or more atmospheric pressure ranges, and / or the estimated altitude is now included in one of two or more altitude ranges, preferably three or more altitude ranges, more preferably four or more altitude ranges, and the data processing / control unit is configured to calculate the amount of fluid to be withdrawn or injected depending on the atmospheric pressure range into which the estimated atmospheric pressure is now included and / or depending on the atmospheric pressure range into which the estimated altitude is now included.

[0016] The data processing / control unit is configured to calculate an amount of fluid to be drained or injected depending on the atmospheric pressure range into which the estimated atmospheric pressure value is newly included and / or depending on the atmospheric pressure range into which the estimated altitude value is newly included, each atmospheric pressure range and / or each altitude range being associated with a respective fluid volume value, and by determining a fluid volume value associated with the atmospheric pressure range into which the estimated atmospheric pressure value is newly included and / or the atmospheric pressure range into which the estimated altitude value is newly included, an amount of fluid to be drained or injected corresponding to the determined fluid volume value is calculated.

[0017] The data processing / control unit is configured to calculate at least one lower limit value and / or at least one upper limit value of at least one atmospheric pressure range and / or at least one altitude range based on at least one reference atmospheric pressure value and / or at least one reference altitude value and at least one atmospheric pressure difference threshold and / or at least one altitude difference threshold.

[0018] The data processing / control unit is configured to calculate at least one fluid volume value associated with each atmospheric pressure range and / or each altitude range, the at least one fluid volume value corresponding to a sub-value of the maximum amount expelled or injected during a maximum atmospheric pressure change and / or maximum altitude change.

[0019] The data processing / control unit x) detecting whether the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold, which is a lower or upper limit value of an atmospheric pressure range, or whether the estimated altitude exceeds at least one altitude threshold, which is a lower or upper limit value of an altitude range.

[0020] The data processing / control unit is configured to exchange data with external control elements including a barometer and / or an altimeter and / or a GPS, and the data processing / control unit is configured to estimate atmospheric pressure based on atmospheric pressure measurement data of the barometer and / or to estimate altitude based on altitude measurement data of the altimeter and / or the GPS.

[0021] The data processing / control unit is configured to record the barometer's atmospheric pressure measurement as an estimate of atmospheric pressure if the measured atmospheric pressure is between 1054 mbar and 694 mbar, and / or to record the altimeter's altitude measurement as an estimate of altitude if the measured altitude is between sea level and 3000 meters.

[0022] The data processing / control unit is configured to calculate the amount of fluid to expel depending on an estimate of the amount of second fluid injected into the inflatable element due to deformation of the reservoir due to a decrease in atmospheric pressure and / or an increase in altitude.

[0023] The data processing / control unit is configured to calculate the amount of fluid to inject depending on an estimate of the amount of second fluid expelled from the inflatable element due to deformation of the reservoir due to an increase in atmospheric pressure and / or a decrease in altitude.

[0024] The data processing / control unit is configured to exchange data with an external control element including a barometer and / or an altimeter and / or a GPS, and is configured to record atmospheric pressure measurements by the barometer and / or altitude measurements by the altimeter and / or altitude measurements by the GPS when commands are executed by the patient in whom the device is implanted via the external control element.

[0025] The data processing / control unit is configured to update the lower and upper limits of the atmospheric pressure range so that the atmospheric pressure measurement is centered in the atmospheric pressure range and / or update the lower and upper limits of the altitude range so that the altitude measurement is centered in the altitude range, based on the recording of the atmospheric pressure measurement from the barometer and / or the altitude measurement from the altimeter and / or the altitude measurement from the GPS.

[0026] The data processing / control unit is configured to increase, preferably by a factor of two, the extent of the atmospheric pressure range around the atmospheric pressure measurement and / or the altitude range around the altitude measurement.

[0027] The data processing / control unit is configured to record atmospheric pressure measurements from the barometer and / or altitude measurements from the altimeter and / or altitude measurements from the GPS and to calculate the amount of fluid to be expelled from the inflatable element to the reservoir by the actuator or the amount of fluid to be injected from the reservoir into the inflatable element by the actuator by applying the atmospheric pressure measurements or the altitude measurements to a function.

[0028] The data processing / control unit is configured to exchange data with external control elements including a barometer and / or an altimeter and to record atmospheric pressure measurements from the barometer and / or altitude measurements from the altimeter at a predetermined frequency.

[0029] The data processing / control unit is configured to control the increase or decrease of the volume of the reservoir by the actuator so as to allow the evacuation or injection of fluid from the inflatable element into the reservoir.

[0030] The data processing / control unit is configured to perform step a) periodically and / or step b) periodically.

[0031] The device comprises an elongated inflatable element configured to be implanted within a human or animal body or used as a penile implant to selectively occlude an anatomical conduit within the human or animal body selected from at least one of the urethra, gastric tract, colon, or rectum.

[0032] According to a second aspect, the present invention relates to an assembly comprising an implantable medical device as described above and an external control element adapted to exchange data with the implantable medical device and configured to be used by an individual in whom the medical device is implanted, the assembly comprising communication means adapted for the implantable medical device and the external control element to communicate with each other.

[0033] According to a third aspect, the present invention provides a method of compensating for atmospheric pressure changes experienced by an implantable medical device, comprising: The medical device comprises a variable volume fluid reservoir deformable under the influence of atmospheric pressure changes, an inflatable element in fluid communication with the reservoir, an actuator adapted to selectively vary the volume of the fluid reservoir, and a data processing / control unit configured to control the selective variation of the volume of the fluid reservoir by the actuator; The method is executed by the data processing / control unit when the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold or when the estimated altitude exceeds at least one altitude threshold. a) sending, by a control unit, at least one command to an actuator to change the volume of the reservoir so as to expel fluid from the inflatable element into the reservoir; and b) sending, by the control unit, at least one command to an actuator to vary the volume of the reservoir so as to inject fluid from the reservoir into the inflatable element.

[0034] According to a fourth aspect, the invention relates to a computer program product comprising code instructions for carrying out the compensation method described above when the program is executed by a computer.

[0035] According to a fifth aspect, the invention relates to a computer readable storage medium having recorded thereon a computer program product comprising code instructions for carrying out the compensation method described above.

[0036] Other features and advantages of the present invention will become apparent from the following description of the preferred embodiments, which description is made with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0037] [Figure 1] 1 is a general view of an implantable medical device within an individual's body and control elements external to the individual's body. [Figure 2] 1 is a schematic cross-sectional view of the interior of a housing according to one embodiment. [Figure 3] FIG. 10 is a diagram showing a breakdown of atmospheric pressure ranges. [Figure 4] FIG. 10 shows a breakdown of atmospheric pressure ranges according to another embodiment. [Figure 5] 1A-1C illustrate steps of a method for compensating for atmospheric pressure changes experienced by an implantable medical device. DETAILED DESCRIPTION OF THE INVENTION

[0038] (device) According to a first aspect, a medical device is proposed that can be implanted in an individual. In this specification, "individual" means a human or an animal. The device is an implantable active medical device that can occlude a natural conduit, such as the urethra (in men), the bladder neck (in women), the gastric tube, the colon, or the rectum. In one example applied to the urethra or bladder neck, the device allows for the treatment of, among other things, urinary incontinence by means of an artificial sphincter that can occlude the urethra or bladder neck. However, the proposed device is more generally a device with a fluid circuit that responds to pressure changes, especially those caused by altitude changes. Other forms that the device may take include, among others, a penile implant or a gastric restriction band.

[0039] A medical device that can be implanted in the human or animal body is shown by way of non-limiting example in FIGS.

[0040] The implantable device 10 comprises: A sealed housing 1 filled with gas, an inflatable element 3 located outside the housing and adapted to be implanted inside the body of an individual; a fluid circuit consisting of a fluid reservoir 5 containing a variable amount of fluid arranged inside the housing and a fluid connection 2 between the reservoir 5 and the inflatable element 3; an actuator 8 disposed within the housing 1 and mechanically coupled to a portion of the fluid reservoir 5 to selectively vary the amount of fluid in the reservoir; and a data processing / control unit 200 configured to control the selective variation of the volume of the fluid reservoir 5 by the actuator 8 and thus configured to control the actuator to move fluid between the reservoir 5 and the inflatable element 3; Unit 200 is also configured to implement a method for compensating for atmospheric pressure changes experienced by the implantable medical device.

[0041] (fluid circuit) The fluid circuit is adapted to be filled with a fluid, in particular a liquid. A change in the volume of the reservoir 5 causes a change in the pressure in the fluid circuit. More specifically, a decrease in the volume of the reservoir 5 causes a transfer of fluid from the reservoir 5 to the inflatable element 3, increasing the pressure in the fluid circuit. Conversely, an increase in the volume of the reservoir 5 causes a transfer of fluid from the inflatable element 3 to the reservoir 5, decreasing the pressure in the fluid circuit.

[0042] The reservoir 5 is preferably a variable volume fluid reservoir adapted to deform under the influence of changes in atmospheric pressure. Thus, the reservoir 5 may include an elastically deformable portion that deforms in response to changes in atmospheric pressure. This deformation changes the volume of the reservoir 5, resulting in a transfer of fluid between the reservoir 5 and the inflatable element 3.

[0043] The reservoir 5 is also provided with an opening that allows fluid to pass from the reservoir 5 to the external inflatable element 3 via the fluid connection 2 .

[0044] The fluid connection 2 may consist of a tube 2 arranged between the reservoir 5 and the inflatable element 3. A first end of the tube 2 opens into the reservoir 5 and a second end of the tube opens into the inflatable element 3.

[0045] The inflatable element 3 may be an inflatable occlusion cuff, particularly when the device 10 is an artificial urinary sphincter. The fluid-filled inflatable occlusion cuff 3 is adapted to completely or partially surround the duct to be occluded.

[0046] Alternatively, the inflatable element 3 may be an inflatable penile implant, having an elongated shape, particularly if the device 10 is an erectile prosthesis.

[0047] (housing) The housing 1, fluid connection 2 and inflatable element 3 are adapted to be implanted inside the body of an individual I, and in Figure 1 the profile on either side of this assembly is shown diagrammatically.

[0048] The housing 1, and in particular the interior volume 11 of the housing 1 surrounding the reservoir 5, is filled with a gas, for example an inert gas.

[0049] (sensor) Advantageously, the housing 1 incorporates a reservoir sensor 102 adapted to measure a value representative of the fluid pressure in the reservoir 5. The reservoir sensor 102 is for example a force sensor or a pressure sensor.

[0050] (external control element) In a particularly advantageous embodiment, an external control element 9 , such as a remote control, located outside the patient's body can be used by the patient or a third party to communicate wirelessly with the medical device 10 .

[0051] In one embodiment, a barometer 90, i.e., an atmospheric pressure sensor, is provided within the device 10, e.g., the housing 1. According to another embodiment, the barometer 10 is located on an outer wall of the housing 1 and is configured to communicate with the device 10. According to yet another embodiment, the barometer 90 is located on an external control element 9 outside the body of the individual in which the device 10 is implanted. The barometer 90 is adapted to measure a value representative of the atmospheric pressure experienced by the implantable medical device 10. When the barometer 90 is located on the external control element 9, the measurement of the value representative of the atmospheric pressure can be performed via the external control element 9, e.g., by the patient himself / herself activating a command of the external control element 9. Also, in one embodiment, an altimeter 92, i.e., an altitude sensor, is located on the external control element 9 outside the body of the individual in which the device 10 is implanted. The altimeter 92 is adapted to measure a value representative of the altitude at which the implantable medical device is located. The measurement of the value representative of the altitude can also be performed by a user controlling the device 10 via the external control element 9.

[0052] Additionally, the barometer 90 and altimeter 92 or GPS ("Global Positioning System") may be configured to perform atmospheric pressure or altitude measurements, respectively, at predetermined frequencies.

[0053] (actuator) The actuator 8 is adapted to control the change in volume of the reservoir 5. In an embodiment, the actuator 8 is adapted to control the linear movement of the movable wall 6, and the bellows 7 is adapted to expand and contract in response to the linear movement of the movable wall 6 controlled by the actuator 8.

[0054] The actuator 8 can be selected from any electromechanical system capable of converting electrical energy into mechanical movement with the required power output to move the movable wall 6 of the variable volume reservoir 5 with the required force and speed. The actuator 8 can in particular be a piezoelectric actuator, an electromagnetic actuator with an electromagnetic motor with or without brushes, coupled with a reduction gear, an electroactive polymer or a shape memory alloy.

[0055] (Data Processing / Control Unit) The device 10 comprises a data processing / control unit 200 configured to control the actuator 8 to move the movable wall 6 of the reservoir 5 to a position corresponding to the determined volume. More particularly, in the example shown in Figure 2, the control unit 200 is configured to send an actuation command to the motor of the actuator 8 in one direction or the other depending on whether an increase or a decrease in the volume of the reservoir 5 is required.

[0056] As discussed above, changes in atmospheric pressure or altitude can cause deformation of the reservoir 5 of the device 10. These deformations can result in uncontrolled infusion or evacuation of fluid into or from the inflatable element 3, increasing or decreasing the fluid pressure within the inflatable element 3. However, if the fluid pressure within the inflatable element 3 is too high, it can damage the tissue of the anatomical conduit that the inflatable element 3 surrounds. On the other hand, if the fluid pressure within the inflatable element 3 is too low, the inflatable element 3 may not adequately occlude the anatomical conduit that it surrounds, potentially causing incontinence in instances where the conduit is the urethra.

[0057] For example, in the embodiment shown in Figure 2, a bellows 7 forms part of the wall of a variable volume reservoir. The bellows is formed from a plurality of elastically deformable protrusions. The bellows 7 may be in the form of an accordion bellows, with the protrusions corresponding to the pleats of an accordion. In a static state, i.e., when no stress is applied by an actuator 8 to change the volume of the reservoir, changes in atmospheric pressure cause deformation of the protrusions, which in turn changes the volume of the reservoir.

[0058] It is therefore necessary to be able to compensate for this evacuation or injection by injecting fluid into or evacuating fluid from the inflatable element 3 .

[0059] The unit 200 is configured to control the injection or drainage of the fluid to be compensated. To this end, the unit 200 is configured to determine whether the atmospheric pressure is lower or higher than at least one atmospheric pressure threshold and / or whether the altitude is lower or higher than at least one altitude threshold. This determination can determine whether the injection or drainage by the unit 200 is to be carried out.

[0060] It should be understood that the device is configured to respond to changes in atmospheric pressure and / or altitude. Atmospheric pressure refers to the atmospheric pressure experienced by device 10. Altitude refers to the altitude at which device 10 is located. These quantities are related in that atmospheric pressure varies linearly with altitude. As altitude increases, atmospheric pressure decreases, and conversely, as altitude decreases, atmospheric pressure increases.

[0061] For clarity, the following description is divided into two parts. The first part relates to configuring unit 200 to compensate for atmospheric pressure values. The second part relates to configuring unit 200 to compensate for altitude values. Since atmospheric pressure and altitude are inversely related (as one increases the other decreases), it should be clear that the altitude embodiment is the same as the inverted embodiment.

[0062] (Atmospheric Pressure Embodiment) Advantageously, the unit 200 is configured to estimate the value of the atmospheric pressure.

[0063] The value of atmospheric pressure may be measured by barometer 90 and then communicated to unit 200. According to an embodiment, unit 200 is configured to record the value of atmospheric pressure measured by barometer 90 upon command by the individual via external control element 9. According to an embodiment, unit 200 is configured to record the value of atmospheric pressure measured by barometer 90 at a predetermined frequency.

[0064] This gives an estimate of the atmospheric pressure, which corresponds to the atmospheric pressure experienced by the device at time tn.

[0065] According to another embodiment, the unit 200 is configured to perform a step a0) of estimating the atmospheric pressure based on at least one value of the fluid pressure in the reservoir 5. The value of the fluid pressure in the reservoir 5 can be measured by the reservoir sensor 102. How to estimate the atmospheric pressure depending on the value of the fluid pressure in the reservoir 5 will not be described in detail here.

[0066] The unit 200 also calculates the reference atmospheric pressure value P_atm t0 The reference value can typically be obtained by a barometer. The reference value is recorded by the unit 200 at time t0, which corresponds to the start-up of the device 10. The reference value is therefore fixed at the start-up of the device 10 and is not intended to be changed (although it can be reset as needed).

[0067] The unit 200 is configured to calculate at least one lower limit and / or at least one upper limit of at least one atmospheric pressure range based on at least one reference atmospheric pressure value and at least one atmospheric pressure difference threshold. Indeed, the unit 200 is configured to determine the atmospheric pressure ranges, i.e., each range is associated with an amount of fluid to be injected or expelled, and depending on the estimated atmospheric pressure, the unit 200 is configured to determine in which atmospheric pressure range the estimated value falls, thereby determining the amount of fluid to be injected or expelled from the inflatable element 3 from the reservoir 5. In this way, the unit 200 is configured to compensate within the device for deformation of the reservoir 5 due to atmospheric pressure changes.

[0068] The unit 200 is configured to determine at least one range, and preferably a plurality of ranges, indeed the unit 200 is preferably configured to determine three or more ranges, more preferably four or more ranges.

[0069] As described above, each atmospheric pressure range is determined based on at least one reference atmospheric pressure value and at least one atmospheric pressure difference threshold. The reference atmospheric pressure value ideally corresponds to the maximum atmospheric pressure value, e.g., the atmospheric pressure at sea level, or approximately 1054 mbar. The atmospheric pressure difference threshold corresponds to the extent of the predetermined range. Typically, this difference threshold is set at startup of the device 10 and is not changed (although it can be reset as needed).

[0070] Thus, referring to FIG. 3 , if the first differential threshold is fixed at 90 mbar, then the first range P1 spans 90 mbar, from 1054 mbar to 964 mbar. The upper limit of P1 is 1054 mbar, and the lower limit of P1 is 964 mbar. If the differential threshold is the same for all ranges determined by unit 200, then the upper limit of the second range P2 is 964 mbar, and the lower limit of P2 is 874 mbar. Similarly, the third range P3 has an upper limit of 874 mbar and a lower limit of 784 mbar. The fourth range P4 has an upper limit of 784 mbar and a lower limit of 694 mbar. According to another embodiment, the atmospheric pressure thresholds (i.e., the extent of the ranges) are not the same for each range.

[0071] In the above example, the upper limit for P1 is 1054 mbar and the lower limit for P4 is 694 mbar, which corresponds to an altitude range from sea level (1054 mbar) to 3000 meters (694 mbar).

[0072] Indeed, device 10 is preferably configured for use at a particular atmospheric pressure and / or altitude. Thus, unit 200 may be configured to compensate for deformations of reservoir 5 caused by changes in atmospheric pressure and / or altitude for atmospheric pressures between 1054 mbar and 694 mbar or altitudes between sea level and 3000 meters. Note that unit 200 may also be configured to compensate for deformations of reservoir 5 caused by changes in atmospheric pressure and / or altitude for different atmospheric pressures or altitudes (e.g., altitudes between sea level and 4000 meters).

[0073] The unit 200 is configured to associate with each range a fluid volume value corresponding to the amount of fluid that will be pumped into or expelled from the inflatable element 3 when the estimated atmospheric pressure falls within the range anew. The fluid volume value associated with each range is ideally set at start-up of the device 10 and never changed (although it can be reset if necessary). Advantageously, the unit 200 is configured to calculate the fluid volume value associated with each range based on a maximum fluid volume corresponding to the amount of fluid expelled or pumped during a maximum atmospheric pressure change. The fluid volume value associated with each range therefore corresponds to a sub-value of the maximum fluid volume.

[0074] The maximum fluid amount is typically an estimate of the volume that will be pumped from the reservoir 5 into the inflatable element 3 at the maximum drop in atmospheric pressure (e.g., a drop in atmospheric pressure of 360 mbar, corresponding to an increase in altitude of 3000 meters). This maximum fluid amount therefore correlates with an estimate of the volume that will be expelled from the inflatable element 3 into the reservoir 5 at the maximum increase in atmospheric pressure (e.g., an increase in atmospheric pressure of 360 mbar, corresponding to an increase in altitude of 3000 meters). The fluid volume values ​​associated with each range may be equal to or different from the other ranges.

[0075] According to a particular embodiment, the unit 200 is configured to update the range. In other words, the range is dynamic. More specifically, the unit 200 is configured to update the range when the value of the atmospheric pressure is measured by the barometer 90 (e.g., upon command by the individual via the external control element 9). By "updating," it is meant that the lower and upper limits of the range are changed. These values ​​are changed depending on the value of the atmospheric pressure measured by the barometer 90. Preferably, the range is changed so that the center of the range, preferably the first range P1, is the measured atmospheric pressure by the barometer 90. For example, if the measured atmospheric pressure by the barometer 90 is 940 mbar (a value included in the range P2 in the example of FIG. 3), the range P1 is changed so that its lower limit is 895 mbar and its upper limit is 985 mbar, with 940 mbar being the center of this new range P1. It should be understood that in this example, an example range spanning 90 mbar is used. Range P2 has an upper limit of 895 mbar and a lower limit of 815 mbar (895 mbar - 90 mbar). Similarly, range P3 has an upper limit of 815 mbar and a lower limit of 725 mbar (815 mbar - 90 mbar). As mentioned above, unit 200 is preferably configured for use at atmospheric pressures above 694 mbar, and therefore range P4 preferably has an upper limit of 725 mbar and a lower limit of 694 mbar. The advantages provided by embodiments having dynamic ranges are discussed in more detail below in connection with other elements of this specification.

[0076] According to a particular embodiment, the unit 200 is configured to change the extent of the range centered on the atmospheric pressure measurement by the barometer 90. Preferably, this range is expanded with respect to the initial range, more preferably expanded by a factor of two. In this way, starting from the center of the newly calculated range, a change of more than 90 mbar in either direction can result in a single range change (e.g., starting from the center of range P2, a change of more than 90 mbar only leads to a change from range P2 to range P3 or from range P2 to range P1). This makes it possible to avoid a sudden ejection or injection of fluid from or into the inflatable element 3, i.e., to compensate for atmospheric pressure changes more gradually and more accurately. Taking the above example, the unit 200 can be configured to reset the center of range P1 to 940 mbar and expand the extent of range P1 to 180 mbar (2 times 90 mbar), as shown in FIG. 4. As a result, the upper limit of range P1 becomes 1030 mbar (940 mbar + 90 mbar) and the lower limit becomes 850 mbar (940 mbar - 90 mbar). Meanwhile, the extent of the other ranges remains unchanged. Therefore, the upper limit of range P2 becomes 850 mbar and the lower limit becomes 760 mbar (850 mbar - 90 mbar).

[0077] The unit 200 is preferably configured to perform the step of x) detecting whether the estimated value of atmospheric pressure exceeds at least one atmospheric pressure threshold, which is a lower or upper limit value of an atmospheric pressure range. In other words, the unit 200 is preferably configured to perform the step of detecting a change in the range into which the estimated value of atmospheric pressure now falls. "Newly" means that the estimated value of atmospheric pressure was previously in another range and now falls into the new range by exceeding the atmospheric pressure threshold. The estimated value of atmospheric pressure is estimated at time tn. A change in range means that the estimated value of atmospheric pressure has exceeded the atmospheric pressure threshold (corresponding to the limit value of the range). Also, at time tn, the individual in which the device 10 is implanted is exposed to lower or higher atmospheric pressure (e.g., due to a change in altitude) than at the previous time.

[0078] In order to detect a change in the range in which the estimated atmospheric pressure value is newly included, the unit 200 is advantageously configured to determine whether the difference between the estimated atmospheric pressure value and the reference atmospheric pressure value exceeds an atmospheric pressure difference threshold. For this purpose, the unit 200 is configured to determine the difference between the estimated atmospheric pressure value and the reference atmospheric pressure value. In other words, the unit 200 is able to evaluate the difference between the estimated atmospheric pressure value and the reference atmospheric pressure value recorded before the estimated atmospheric pressure. It is understood that the unit 200 is configured to detect an increase or decrease in atmospheric pressure that exceeds a predetermined atmospheric pressure increase or decrease threshold. For example, suppose the estimated atmospheric pressure is 900 mbar and the reference atmospheric pressure is 1054 mbar. The difference between the estimated atmospheric pressure value and the reference atmospheric pressure value is 154 mbar. It is understood that the reference value was obtained before the estimated atmospheric pressure, so the device 10 experiences a decrease in atmospheric pressure of 154 mbar (which may correspond to an increase in altitude).

[0079] This difference is then compared with an atmospheric pressure difference threshold or set of atmospheric pressure difference thresholds. As mentioned above, the atmospheric pressure difference threshold corresponds to the spread of the ranges. Take for example the case where the spreads between the ranges are equal and the atmospheric pressure difference threshold is equal between the ranges, for example 90 mbar. In the above example, the atmospheric pressure difference is 154 mbar, which is greater than 90 mbar but less than 180 mbar (2 x 90 mbar). The atmospheric pressure difference is therefore above the difference threshold but below the set of two difference thresholds. The unit is configured to infer from this that the estimated atmospheric pressure (i.e. 900 mbar) is in range P2. In response, the unit 200 is configured to determine whether this range is the same as the range that the atmospheric pressure estimate fell within at time tn-1, which is earlier than time tn. If at time tn-1 the estimated atmospheric pressure was within range P1, unit 200 is configured to detect a change in range and to warn that the new estimated atmospheric pressure (at time tn) is below the atmospheric pressure threshold, i.e., the lower limit of range P1. Thus, unit 200 is configured to determine whether the estimated atmospheric pressure is below or above the atmospheric pressure threshold when a change in the range within which the estimated atmospheric pressure is located is detected.

[0080] If it is determined that the estimated atmospheric pressure exceeds the atmospheric pressure threshold (the estimated atmospheric pressure at time tn falls within a range that is different from the estimated atmospheric pressure at time tn-1), the unit 200 is configured to control the evacuation or injection of fluid. In fact, this range change indicates that the reservoir 5 may have been deformed such that fluid in the inflatable element is unintentionally injected or ejected. These unwanted injections or ejections may affect the integrity of the tissue surrounded by the inflatable element (in the case of excessive pressure due to fluid injection) or, conversely, cause urine leakage (in the case of insufficient pressure due to fluid ejection).

[0081] Therefore, unit 200 is preferably configured to perform step a01) or b01) of calculating the amount of fluid to be withdrawn or injected. Preferably, as described above, a fluid amount is associated with each range, and unit 200 is advantageously configured to select the amount of fluid associated with the range into which the new estimate of atmospheric pressure falls.

[0082] The unit 200 is configured to execute step a) of instructing the actuator 8 to expel at least one discharge of fluid from the inflatable element 3 to the reservoir 5 if the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold and if the atmospheric pressure is lower than at least one atmospheric pressure threshold. To do this, the unit is configured to control an increase in the volume of the reservoir 5 so as to allow the discharge of fluid in the inflatable element 3. In this case, the unit 200 compensates for a decrease in atmospheric pressure (which may be related to an increase in altitude) that causes the injection of fluid from the reservoir 5 into the inflatable element 3. This particular case corresponds to the above-mentioned example corresponding to the change in range from P1 to P2. The discharged fluid can be discharged in one go or in several batches.

[0083] The unit 200 is also configured to perform step b) of instructing at least one injection of fluid from the reservoir 5 into the inflatable element 3 if the estimated value of the atmospheric pressure exceeds at least one atmospheric pressure threshold and if the atmospheric pressure is higher than the at least one atmospheric pressure threshold. To do this, the unit is configured to control a decrease in the volume of the reservoir 5 so as to allow the injection of fluid into the inflatable element 3. In this case, the unit 200 compensates for an increase in atmospheric pressure (which may be related to a decrease in altitude) that causes the expulsion of fluid in the inflatable element 3.

[0084] Additionally, the dynamic range embodiment described above avoids the following situation: If unit 200 estimates a value of atmospheric pressure within range P2 near the upper limit of range P2, the limit is exceeded and a drain of fluid is indicated. Then, upon command from the individual via external control element 9, barometer 90 measures a value of atmospheric pressure that updates the estimate of atmospheric pressure (the value measured by the barometer is assumed to be more reliable than the estimate by unit 200 and is therefore corrected). This measurement falls within range P1 near the lower limit of range P1 (and thus near the upper limit of P2), and a fluid infusion is indicated. If the patient remains at the same altitude, repeated infusion and drainage of fluid will occur, resulting in alternating transitions from one range to another, potentially wasting energy by device 1 and causing discomfort to the patient. By adapting the range limits, the dynamic range embodiment avoids this phenomenon, which occurs when the patient remains at atmospheric pressure / altitude values ​​near the range limits.

[0085] Advantageously, the unit 200 is configured to command the injection or withdrawal of fluid when a value of the atmospheric pressure is measured by the barometer 90 (in particular, upon command by the individual via the external control element 9). In other words, instead of the injection or withdrawal of fluid being controlled automatically by the unit 200 in response to an estimated value of the atmospheric pressure, the injection or withdrawal of fluid can be controlled by a user via the external control element 9. More specifically, the unit 200 is configured to calculate an amount of fluid to inject or withdraw in response to a command by the individual via the external control element 9 (and thus the value of the atmospheric pressure measured by the barometer 90). Preferably, this amount is calculated based on a function and the measurement of the atmospheric pressure by the barometer 90. Preferably, this function is an affine function, i.e. of the form y=a*x+b (x corresponds to the measurement of the atmospheric pressure by the barometer 90, y corresponds to the amount of fluid to be withdrawn or injected, and a and b are real constants). It is therefore understood that unit 200 is configured to calculate the amount of fluid to be withdrawn or infused by applying a function to the atmospheric pressure measurement by barometer 90. Note that if the atmospheric pressure measurement by barometer 90 is the same as the current atmospheric pressure estimate ("current" meaning the most recent estimate of the current atmospheric pressure determined by unit 200), the amount of fluid to be withdrawn or infused is zero. It is also understood that unit 200 is configured to determine whether the measured atmospheric pressure is greater than or less than the current atmospheric pressure estimate, and therefore unit 200 is configured to determine whether to infuse or withdraw a predetermined amount of fluid. This embodiment can be combined with an embodiment having a dynamic range to provide consistent compensation for changes in atmospheric pressure. Therefore, according to this embodiment, unit 200 provides more regular compensation for any fluctuations in atmospheric pressure, ensuring greater comfort and safety for the patient. Furthermore, according to this embodiment, compensation can be directly controlled by a command from the patient.

[0086] Thus, device 10 is adapted to compensate for atmospheric pressure changes. Advantageously, device 10 is adapted to compensate for deformation of reservoir 5 caused by atmospheric pressure changes. An individual having device 10 implanted therein can be exposed to atmospheric pressure changes (e.g., increases or decreases in altitude) with limited risk of damaging the tissue surrounding the anatomical conduit. Preferably, unit 200 is configured to perform at least steps a) and b) periodically, for example, once every hour, more preferably once every 30 minutes, and even more preferably once every 10 minutes.

[0087] (Advanced embodiment) Advantageously, the unit 200 is configured to estimate an altitude value, which may be measured by an altimeter 92 of the external control element 9 and then transmitted to the unit 200. According to an embodiment, the unit 200 is configured to record the altitude value measured by the altimeter 92 upon command by the individual via the external control element 9. According to an embodiment, the unit 200 is configured to record the altitude value measured by the altimeter 92 at a predetermined frequency.

[0088] The unit 200 also calculates the reference altitude value A_atm t0 The reference value can typically be obtained by an altimeter. The reference value was recorded by the unit 200 at time t0, which corresponds to the start-up of the device 10. The reference value is therefore fixed at the start-up of the device 10 and is not intended to be changed (although it can be reset as needed).

[0089] The remainder of the altitude embodiment is similar to the atmospheric pressure embodiment, with some differences: First, it is understood that the atmospheric pressure estimates, atmospheric pressure thresholds, atmospheric pressure ranges, etc. correspond to the altitude estimates, altitude thresholds, altitude ranges, etc., respectively, in the altitude embodiment.

[0090] Also, as noted above, a decrease in altitude is accompanied by an increase in atmospheric pressure, and conversely, an increase in altitude is accompanied by a decrease in atmospheric pressure, and it will therefore be understood that a decrease in altitude is compensated for by the injection of fluid into the inflatable element, and an increase in altitude is compensated for by the evacuation of fluid from the inflatable element.

[0091] Thus, altitude embodiments can be derived simply based on atmospheric pressure embodiments, taking these differences into account.

[0092] (assembly) According to a second aspect, an assembly is proposed comprising an implantable medical device 10 as described above and an external control element 9 adapted for use by, for example, an individual in whom the system is implanted. The implantable medical device 10 and the external control element 9 comprise communication means adapted for communicating with each other. The communication means of the implantable device 10 can be integrated into the housing 1.

[0093] (method) Referring to FIG. 5 , according to a third aspect, there is provided a method of compensating for atmospheric pressure changes experienced by an implantable medical device 10, comprising: a step executed by the data processing / control unit when the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold or when the estimated altitude exceeds at least one altitude threshold; a) sending, by a control unit, at least one command to an actuator to change the volume of the reservoir so as to expel fluid from the inflatable element into the reservoir; and b) sending by the control unit at least one command to an actuator to vary the volume of the reservoir so as to inject fluid from the reservoir into the inflatable element.

[0094] (Program products and storage media) According to a fourth aspect, a computer program product is proposed comprising code instructions for carrying out a method for compensating for atmospheric pressure changes experienced by an implantable medical device 10.

[0095] According to a sixth aspect, a computer readable storage medium is proposed, wherein the computer program product comprises code instructions for performing a method for (compensating for) atmospheric pressure changes experienced by the implantable medical device 10.

[0096] The present invention is not limited to the embodiments described above and shown in the accompanying drawings, as modifications are possible, particularly in terms of the construction of the various technical features or by the substitution of technical equivalents, without departing from the general teaching.

Claims

1. An implantable medical device (10), comprising: a variable volume fluid reservoir (5) deformable under the influence of atmospheric pressure changes, an inflatable element (3) in fluid communication with said reservoir (5), an actuator (8) adapted to selectively vary the volume of said fluid reservoir (5), and a data processing / control unit (200) configured to control the selective variation of the volume of said fluid reservoir (5) by said actuator (8), said unit (200) being configured to: a) controlling, by said data processing / control unit (200), at least one discharge of fluid from said inflatable element (3) into said reservoir (5) by said actuator (8); b) an apparatus configured to perform at least one of the steps of controlling, by said data processing / control unit (200), at least one injection of fluid from said reservoir (5) into said inflatable element (3) by said actuator (8).

2. The data processing / control unit (200) and / or, performing step a) if the estimated atmospheric pressure exceeds the at least one atmospheric pressure threshold and the atmospheric pressure is lower than the at least one atmospheric pressure threshold, or if the estimated altitude exceeds the at least one altitude threshold and the estimated altitude is higher than the at least one altitude threshold.

2. The apparatus of claim 1, configured to perform step b) if the estimated atmospheric pressure exceeds the at least one atmospheric pressure threshold and the atmospheric pressure is higher than the at least one atmospheric pressure threshold, or if the estimated altitude exceeds the at least one altitude threshold and the estimated altitude is lower than the at least one altitude threshold.

3. 3. The device according to claim 1 or 2, wherein the data processing / control unit (200) is configured to perform a step a01) or b01) of calculating the amount of fluid to be withdrawn or injected before step a) or b).

4. The device according to any one of claims 1 to 3, wherein the data processing / control unit (200) is configured to perform a step a0) of estimating atmospheric pressure based on at least one value of fluid pressure in the reservoir (5).

5. 5. The device according to claim 1, wherein the data processing / control unit (200) is configured to calculate the amount of fluid to be withdrawn or injected depending on the atmospheric pressure range into which the estimated atmospheric pressure falls, for which the atmospheric pressure threshold is a lower or upper limit value, and / or depending on the altitude range into which the estimated altitude falls, for which the altitude threshold is a lower or upper limit value.

6. 6. The device according to claim 1, wherein the estimated atmospheric pressure falls within one of a plurality of atmospheric pressure ranges and / or the estimated altitude falls within a new one of a plurality of altitude ranges, and wherein the data processing / control unit (200) is configured to calculate an amount of fluid to be withdrawn or injected depending on the atmospheric pressure range within which the estimated atmospheric pressure falls and / or depending on the atmospheric pressure range within which the estimated altitude falls.

7. 7. The device of claim 6, wherein the estimated atmospheric pressure is now included in one of two or more atmospheric pressure ranges, preferably three or more atmospheric pressure ranges, more preferably four or more atmospheric pressure ranges, and / or the estimated altitude is now included in one of two or more altitude ranges, preferably three or more altitude ranges, more preferably four or more altitude ranges, and wherein the data processing / control unit (200) is configured to calculate the amount of fluid to be withdrawn or injected depending on the atmospheric pressure range into which the estimated atmospheric pressure is now included and / or depending on the atmospheric pressure range into which the estimated altitude is now included.

8. 8. The device of claim 6 or 7, wherein the data processing / control unit (200) is configured to calculate an amount of fluid to be extracted or injected depending on the atmospheric pressure range into which the estimated atmospheric pressure value is newly included and / or depending on the atmospheric pressure range into which the estimated altitude value is newly included, each atmospheric pressure range and / or each altitude range being associated with a respective fluid volume value, and the amount of fluid to be extracted or injected corresponding to the determined fluid volume value is calculated by determining a fluid volume value associated with the atmospheric pressure range into which the estimated atmospheric pressure value is newly included and / or the atmospheric pressure range into which the estimated altitude value is newly included.

9. 9. The apparatus according to claim 5, wherein the data processing / control unit (200) is configured to calculate at least one lower limit value and / or at least one upper limit value of at least one said atmospheric pressure range and / or at least one said altitude range based on at least one reference atmospheric pressure value and / or at least one reference altitude value and at least one atmospheric pressure difference threshold and / or at least one altitude difference threshold.

10. 10. The apparatus of claim 5, wherein the data processing / control unit (200) is configured to calculate at least one fluid volume value associated with each atmospheric pressure range and / or each altitude range, the at least one fluid volume value corresponding to a sub-value of the maximum amount to be expelled or injected during a maximum atmospheric pressure change and / or maximum altitude change.

11. The data processing / control unit (200) x) detecting whether the estimated value of atmospheric pressure exceeds at least one threshold atmospheric pressure, the threshold being a lower or upper value of a range of atmospheric pressures, or whether the estimated value of altitude exceeds at least one threshold altitude, the threshold being a lower or upper value of a range of altitudes.

12. 12. The device according to claim 1, wherein the data processing / control unit (200) is configured to exchange data with an external control element (9) including a barometer (90) and / or an altimeter (92) and / or a GPS, and wherein the data processing / control unit (200) is configured to estimate atmospheric pressure based on atmospheric pressure measurement data of the barometer (90) and / or to estimate altitude based on altimetry data of the altimeter (92) and / or the GPS.

13. 13. The apparatus of claim 12, wherein the data processing / control unit (200) is configured to record an atmospheric pressure measurement by the barometer (90) as an estimate of the atmospheric pressure if the measured atmospheric pressure is between 1054 mbar and 694 mbar, and / or to record an altitude measurement by the altimeter (92) as an estimate of the altitude if the measured altitude is between sea level and 3000 meters.

14. The device according to any one of claims 1 to 13, wherein the data processing / control unit (200) is configured to calculate the amount of fluid to be expelled depending on an estimate of the amount of second fluid injected into the inflatable element (3) due to deformation of the reservoir due to a decrease in atmospheric pressure and / or an increase in altitude.

15. The device according to any one of claims 1 to 14, wherein the data processing / control unit (200) is configured to calculate the amount of fluid to inject depending on an estimate of the amount of second fluid expelled from the inflatable element (3) due to deformation of the reservoir (5) due to an increase in atmospheric pressure and / or a decrease in altitude.

16. 16. The device according to any one of claims 1 to 15, wherein the data processing / control unit (200) is configured to exchange data with an external control element (9) comprising a barometer (90) and / or an altimeter (92) and / or a GPS, and is configured to record atmospheric pressure measurements by the barometer (90) and / or altitude measurements by the altimeter (92) and / or altitude measurements by the GPS when commands are executed by a patient in whom the device is implanted via the external control element (9).

17. The device of any one of claims 5 to 11 in combination with claim 16, or the device of any one of claims 12 to 15 in combination with claims 5 and 16, wherein the data processing / control unit (200) is configured to update the lower and upper limits of the atmospheric pressure range so that the atmospheric pressure measurement is at the center of the atmospheric pressure range and / or update the lower and upper limits of the altitude range so that the altitude measurement is at the center of the altitude range, depending on the recording of the atmospheric pressure measurement by the barometer (90) and / or the altitude measurement by the altimeter (92) and / or the altitude measurement by the GPS.

18. 18. The device of claim 17, wherein the data processing / control unit (200) is configured to increase, preferably by a factor of two, the extent of the atmospheric pressure range around the atmospheric pressure measurement and / or the altitude range around the altitude measurement.

19. 19. The device according to claim 17 or 18, wherein the data processing / control unit (200) is configured to record atmospheric pressure measurements by the barometer (90) and / or altitude measurements by the altimeter (92) and / or altitude measurements by the GPS and to calculate the amount of fluid to be expelled by the actuator (8) from the inflatable element (3) into the reservoir (5) or the amount of fluid to be injected by the actuator (8) from the reservoir (5) into the inflatable element (3) by applying the atmospheric pressure measurements or the altitude measurements to a function.

20. 20. The apparatus of any one of claims 1 to 19, wherein the data processing / control unit (200) is configured to exchange data with an external control element (9) including a barometer (90) and / or an altimeter (92) and to record atmospheric pressure measurements by the barometer (90) and / or altitude measurements by the altimeter (92) at a predetermined frequency.

21. 21. The device according to any one of claims 1 to 20, wherein the data processing / control unit (200) is configured to instruct the actuator (8) to increase or decrease the volume of the reservoir (5) so as to allow the expulsion or injection of fluid from the inflatable element (3) into the reservoir (5).

22. Apparatus according to any one of the preceding claims, wherein the data processing / control unit (200) is adapted to perform step a) periodically and / or step b) periodically.

23. 23. An implantable medical device according to any one of claims 1 to 22, comprising an elongate inflatable element configured to be implanted within a human or animal body to selectively occlude an anatomical conduit within the human or animal body selected from at least one of the urethra, gastric tract, colon or rectum, or configured for use as a penile implant.

24. Assembly comprising an implantable medical device according to any one of claims 1 to 23 and an external control element (9) adapted to exchange data with said implantable medical device and configured to be used by an individual in whom said medical device is implanted, An assembly comprising communication means adapted for said implantable medical device and said external control element (9) to communicate with each other.

25. A method for compensating for atmospheric pressure changes experienced by an implantable medical device (10), comprising: The medical device (10) comprises a variable volume fluid reservoir (5) deformable under the influence of atmospheric pressure changes, an inflatable element (3) in fluid communication with the reservoir (5), an actuator (8) adapted to selectively vary the volume of the fluid reservoir (5), and a data processing / control unit (200) configured to control the selective variation of the volume of the fluid reservoir (5) by the actuator (8), The method is executed by the data processing / control unit (200) when the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold or when the estimated altitude exceeds at least one altitude threshold. a) sending by said control unit at least one command to said actuator (8) to vary the volume of said reservoir (5) so as to expel fluid from said inflatable element (3) into said reservoir (5); b) sending by said control unit at least one command to said actuator (8) to vary the volume of said reservoir (5) so as to inject fluid from said reservoir (5) into said inflatable element (3).

26. 1. A computer program product comprising code instructions for carrying out a method for compensating for atmospheric pressure changes experienced by an implantable medical device (10), comprising: The medical device (10) comprises a variable volume fluid reservoir (5) deformable under the influence of atmospheric pressure changes, an inflatable element (3) in fluid communication with the reservoir (5), an actuator (8) adapted to selectively vary the volume of the fluid reservoir (5), and a data processing / control unit (200) configured to control the selective variation of the volume of the fluid reservoir (5) by the actuator (8), When the program is executed by a computer, the method is executed by the data processing / control unit (200) when the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold or when the estimated altitude exceeds at least one altitude threshold. a) sending by said control unit at least one command to said actuator (8) to vary the volume of said reservoir (5) so as to expel fluid from said inflatable element (3) into said reservoir (5); b) sending, by said control unit, at least one command to said actuator (8) to vary the volume of said reservoir (5) so as to inject fluid from said reservoir (5) into said inflatable element (3).

27. A computer-readable storage medium having recorded thereon a computer program product including code instructions for carrying out a method for compensating for atmospheric pressure changes experienced by an implantable medical device (10), comprising: The medical device (10) comprises a variable volume fluid reservoir (5) deformable under the influence of atmospheric pressure changes, an inflatable element (3) in fluid communication with the reservoir (5), an actuator (8) adapted to selectively vary the volume of the fluid reservoir (5), and a data processing / control unit (200) configured to control the selective variation of the volume of the fluid reservoir (5) by the actuator (8), The method is executed by the data processing / control unit (200) when the estimated atmospheric pressure exceeds at least one atmospheric pressure threshold or when the estimated altitude exceeds at least one altitude threshold. a) sending by said control unit at least one command to said actuator (8) to vary the volume of said reservoir (5) so as to expel fluid from said inflatable element (3) into said reservoir (5); b) sending by said control unit at least one command to said actuator (8) to vary the volume of said reservoir (5) so as to inject fluid from said reservoir (5) into said inflatable element (3).

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