Method for estimating value representative of fluid pressure in expandable element of implantable medical device

Abstract

The invention relates to a method for estimating a value representative of a first pressure, the first pressure being a fluid pressure in an expandable element (3) of an implantable medical device (10), the implantable medical device (10) comprising a fluid reservoir (5) having a selectively variable volume, the reservoir (5) being deformable under the action of a change in atmospheric pressure, and the expandable element (3) is in fluid communication with the reservoir (5). The method comprises the following steps implemented by a data processing and control unit (200) of the apparatus: a) determining a value representative of a second pressure, the second pressure being a fluid pressure in the reservoir (5); b) estimating a value representative of the first pressure as a function of a value representative of the second pressure and as a function of a parameter (L) dependent on a value representative of a maximum change in fluid pressure in the expandable element (3) caused by a change in atmospheric pressure.

Description

Technical Field

[0001] The invention relates to a method for estimating a value representative of the pressure of a fluid in an expandable element of an implantable medical device comprising a selectively variable volume fluid reservoir. Background Art

[0002] Many medical devices take the form of systems that can be implanted into a human or animal subject. In particular, such devices may be artificial urinary sphincters for combating urinary incontinence, gastric bands or rings suitable for constricting the stomach for the purpose of combating obesity, inflatable penile implants for erectile prostheses, etc.

[0003] In a manner known per se, the implantable system can be hydraulically operated and can in particular comprise a variable volume fluid reservoir and an expandable element, the expandable element containing the variable volume of fluid. The expandable element is fluidically connected to the variable volume fluid reservoir so as to be able to transfer the fluid from the reservoir to the expandable element and vice versa.

[0004] In the case of an occlusive implantable system, such as an artificial urinary sphincter, the inflatable element is an inflatable occlusive cuff capable of selectively occluding an anatomical conduit (such as the urethra in males, or the bladder neck in females). Fluid can be transferred from a reservoir to the cuff to increase the pressure applied to the conduit, and conversely from the cuff to the reservoir to reduce the pressure applied to the conduit. Thus, depending on the volume of fluid in the cuff, more or less pressure can be applied to the anatomical conduit to be occluded.

[0005] The elements of implantable fluid systems can be sensitive to changes in atmospheric pressure (e.g., due to changes in altitude) and deform. For example, the reservoir of an implantable fluid system can include a part that can be elastically deformed, which is deformed according to changes in atmospheric pressure. This deformation can cause fluid to be injected into the cuff uncontrollably or fluid is taken out of the cuff and therefore increase or decrease the fluid pressure in the cuff.

[0006] However, such variations in the fluid pressure in the cuff are to be avoided. In the case of an artificial urinary sphincter, overpressures are likely to damage the tissue around which the cuff is arranged, for example by causing lesions in this tissue. It is therefore necessary to control these overpressures in order to limit the corresponding risk of damage to the tissue. This involves being able to estimate the pressure variations in the inflatable element in order to be able to subsequently compensate for them where applicable. Summary of the invention

[0007] It is an object of the present invention to reliably calculate the fluid pressure in an expandable element of an implantable medical device.

[0008] It is another object of the present invention to reliably calculate the atmospheric pressure experienced by an implantable medical device.

[0009] According to a first aspect, the invention relates to a method for estimating a value representative of a first pressure, the first pressure being the pressure of a fluid in an expandable element of an implantable medical device, the implantable medical device comprising a selectively variable volume fluid reservoir capable of deforming under the effect of atmospheric pressure variations, the expandable element being in fluid connection with said reservoir, the method comprising the following steps implemented by a data control and processing unit of the device:

[0010] a) determining a value representing a second pressure, the second pressure being the pressure of the fluid in the reservoir,

[0011] b) estimating a value representative of the first pressure based on the value representative of the second pressure and based on a parameter dependent on a value representative of a maximum change in pressure of the fluid in the inflatable element caused by a change in atmospheric pressure.

[0012] According to the advantageous and non-limiting features, taken alone or in any combination:

[0013] - the value representative of the second pressure is determined based on at least one value representative of the pressure of the fluid in the reservoir measured by a sensor included in the implantable medical device;

[0014] - the value representing the first pressure is determined based on the value representing the reference second pressure, the value representing the reference second pressure being determined based on the value representing the pressure of the fluid in the reservoir measured by the sensor;

[0015] - the value representing the first pressure is determined based on the value representing the reference first pressure, which is determined based on the value representing the reference second pressure measured by the sensor and based on the value representing the reference atmospheric pressure measured by the barometer;

[0016] - The barometer is arranged on the outer wall of the box 1 or inside the box 1;

[0017] - the barometer is included in an external control element suitable for exchanging data with an implanted medical device and wherein the value representative of the reference atmospheric pressure is measured following a command implemented by the individual in whom the device is implanted via the external control element;

[0018] - updating the value representing the reference first pressure based on the updated value representing the reference atmospheric pressure and the updated value representing the reference second pressure each time a command is implemented;

[0019] - updating the value representing the reference first pressure at least once a day based on the updated value representing the reference atmospheric pressure and based on the updated value representing the reference second pressure;

[0020] - updating the value representing the reference second pressure at least once a day, preferably at least three times a day, still preferably at least five times a day;

[0021] - the value representing the second pressure is an average or median of a plurality of values ​​representing the pressure of the fluid in the reservoir;

[0022] - the value representing the second pressure is determined based on an average or median of at least three values ​​representing the pressure of the fluid in the reservoir;

[0023] - the value representative of the second pressure is determined based on the value representative of the first change in pressure of the fluid in the reservoir caused by a change in volume of the reservoir implemented by an actuator of the device;

[0024] - a value representing a second pressure is determined based on a value representing a second change in pressure of the fluid in the reservoir caused by a change in orientation of the device;

[0025] - indicates that the value of the first pressure is calculated based on:

[0026] deuxième_P L

[0027] deuxième_P is a value representing a second pressure, and

[0028] L is said parameter depending on the maximum change in pressure in the inflatable element caused by a change in atmospheric pressure;

[0029] - said parameter is previously obtained based on one or more measurements of a value representative of a third variation in the pressure of the fluid in the reservoir caused by one or more variations in the atmospheric pressure;

[0030] - The value representing the first pressure is determined by calculating:

[0031]

[0032] première_P_ref is a value representing a reference first pressure, and

[0033] deuxième_P_ref is a value indicating a reference second pressure.

[0034] According to a second aspect, the invention relates to a method for estimating a value representing the atmospheric pressure to which an implantable medical device is subjected, comprising the estimation method previously described and comprising a step c) of estimating the value representing the atmospheric pressure by subtracting the value representing the second pressure from the value representing the first pressure.

[0035] According to a third aspect, the invention relates to an implantable medical device comprising a fluid reservoir of variable volume, an expandable element fluidically connected to said reservoir and a data control and processing unit, said unit being configured to implement the estimation method previously described.

[0036] According to the advantageous and non-limiting features, taken alone or in any combination:

[0037] - the device is configured to be implanted in a human or animal body to selectively close an anatomical passage in said human or animal body, the anatomical passage being taken from at least one of the following ducts: urethra, gastric tube, colon and rectum;

[0038] - The device comprises an expandable element of an elongated shape configured to function as a penile implant.

[0039] According to a fourth aspect, the present invention relates to a component comprising an implantable medical device as described above and an external control element suitable for exchanging data with the implantable medical device and suitable for use by an individual in which the medical device is implanted, wherein the implantable medical device and the external control element comprise communication means suitable for communicating with each other.

[0040] According to a fifth aspect, the invention relates to a computer program product comprising code instructions for performing the method previously described when said program is executed by an electronic control unit.

[0041] According to a sixth aspect, the invention relates to a storage device readable by a piece of computer equipment, on which a computer program product comprises code instructions for executing the method previously described. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Other features and advantages of the present invention will become apparent after reading the following description of the preferred embodiment. This description will be given with reference to the accompanying drawings, in which:

[0043] - Figure 1 An overall view of a medical device implantable within an individual's body and control elements external to the individual's body is shown;

[0044] - Figure 2 is a schematic cross-sectional view of the interior of a box according to an embodiment;

[0045] - Figure 3 The steps of a method for estimating a first pressure are shown;

[0046] - Figure 4 is a graph showing the evolution of different pressures as a function of increasing altitude;

[0047] - Figure 5 The steps of a method for estimating atmospheric pressure are shown. DETAILED DESCRIPTION

[0048] equipment

[0049] According to a first aspect, a medical device implantable in an individual is proposed. In this text, the term "individual" should be understood to mean a human or an animal. The device is an active implantable medical device capable of occluding a natural conduit, such as, for example, the urethra (in men), the bladder neck (in women), a gastric tube, the colon or the rectum. In the scenario of application to the urethra or the body of the bladder, the device in particular enables the fight against urinary incontinence by means of an artificial sphincter capable of occluding the urethra or the bladder neck. However, the proposed device is more generally a device comprising a fluid circuit sensitive to changes in pressure (in particular generated by changes in altitude). Other forms that the device may take include, in particular, penile implants and gastric constriction bands.

[0050] exist Figure 1 and Figure 2 Detailed Description of the Invention Medical devices that may be implanted in a human or animal body are illustrated by way of non-limiting example.

[0051] The implantable device 10 comprises:

[0052] - a sealed box 1 containing a gas,

[0053] - an expandable element 3 suitable for implantation in an individual outside the housing,

[0054] a fluid circuit comprising a fluid reservoir 5 with a variable fluid volume arranged in the housing and a fluid connection 2 between the reservoir 5 and the expandable element 3,

[0055] an actuator 8 arranged in the housing 1 and mechanically coupled to a portion of the fluid reservoir 5 to selectively vary the volume of the fluid in said reservoir,

[0056] a control unit 100 configured to control the actuator 8 in order to transfer fluid between the reservoir 5 and the inflatable element 3,

[0057] - A data control and processing unit 200 configured to implement a method for estimating a value representative of the pressure of the fluid in the inflatable element 3, the so-called "first pressure".

[0058] The fluid circuit is adapted to be filled with a fluid. 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 expandable element 3 and causes an increase in the pressure in the fluid circuit. Conversely, an increase in the volume of the reservoir 5 causes a transfer of fluid from the expandable element 3 to the reservoir 5 and causes a decrease in the pressure in the fluid circuit.

[0059] The reservoir 5 is preferably a variable volume fluid reservoir that is easily deformed under the effect of changes in atmospheric pressure. The reservoir 5 may therefore include a portion that is elastically deformable, which deforms as a function of changes in atmospheric pressure. This deformation may cause a change in the volume of the reservoir 5 and thus cause a fluid transfer between the reservoir 5 and the expandable element 3.

[0060] The reservoir 5 further comprises an orifice which is used to transfer fluid from the reservoir 5 to the expandable element 3 via the fluid connection 2 or from the expandable element 3 to the reservoir 5 via the fluid connection 2 .

[0061] The fluid connection 2 may be constituted by a tube 2 arranged between the reservoir 5 and the expandable element 3. A first end of the tube 2 opens into the reservoir 5 and a second end of the tube 2 opens into the expandable element 3.

[0062] The inflatable element 3 may be an inflatable occlusion cuff, in particular when the device 10 is an artificial urinary sphincter. The inflatable occlusion cuff 3 filled with a fluid may be adapted to fully or partially surround the conduit to be occluded.

[0063] In a variant, the inflatable element 3 may be an inflatable penile implant and therefore have an elongated shape, in particular when the device 10 is an erection prosthesis.

[0064] The housing 1, the fluid connection 2 and the expandable element 3 are suitable for being implanted in the body of an individual I, and their contours are as follows: Figure 1 Schematically shown on either side of this assembly.

[0065] The tank 1 , in particular the inner volume 11 of the tank 1 surrounding the reservoir 5 , contains a gas, for example an inert gas.

[0066] The actuator 8 is adapted to control the change of the volume of the reservoir 5. The actuator 8 is controlled by a control unit 100. In a certain embodiment, the actuator 8 is adapted to control the linear displacement of the movable wall 6, and the bellows 7 is adapted to extend or compress as a function of said linear displacement of the movable wall 6 controlled by the actuator 8.

[0067] The actuator 8 may be selected from any electromechanical system that enables the conversion of electrical energy into mechanical movement with the required power to enable the displacement of the movable wall 6 of the variable volume reservoir 5 with the required force and speed. The actuator 8 may in particular be a piezoelectric actuator, an electromagnetic actuator, which may include a brushed or brushless electromagnetic motor coupled or not to a reduction gear, an electroactive polymer or a memory alloy.

[0068] The control unit 100 is configured to control the actuator 8 so as to displace the movable wall 6 of the reservoir 5 to a position corresponding to the determined volume. Figure 2In the example illustrated in , the control unit 100 is adapted to send instructions to the motor of the actuator 8 to operate in one direction or the other, depending on whether an increase or decrease in the volume of the reservoir 5 is required.

[0069] Advantageously, the housing 1 encloses a reservoir sensor 102 adapted to measure a value representative of the pressure of the fluid in the reservoir 5 (the so-called "second pressure"). The reservoir sensor 102 may be, for example, a force sensor or a pressure sensor.

[0070] Particularly advantageously, an external control element 9 , such as a remote control, outside the patient's body can be used by the patient or a third party to communicate with the medical device 10 in a wireless manner, for example by radio frequency.

[0071] In some embodiments, a barometer 90 (i.e., an atmospheric pressure sensor) is included in the device 10, for example in the housing 1. According to another embodiment, the barometer 10 is arranged on the outer wall of the housing 1 and is configured to communicate with the device 10. According to still another embodiment, the barometer 90 may be arranged in a control element 9 outside the body of the individual in which the device 10 is implanted. The barometer 90 is suitable for measuring a value representing the atmospheric pressure to which the implantable medical device 10 is subjected. In the case where the barometer 90 is arranged in the external control element 9, the measurement of the value representing the atmospheric pressure can thus be performed via the external control element 9, for example when the patient himself activates a command of the external control element 9.

[0072] Alternatively or in combination, the barometer 90 may also be configured to perform measurements of the atmospheric pressure at a predetermined frequency.

[0073] Components

[0074] According to a second aspect, a component is provided, which comprises an implantable medical device 10 as described above and an external control element 9 suitable for use by an individual (e.g., an individual in whom the system is implanted). The implantable medical device 10 and the external control element 9 comprise communication means suitable for communicating with each other in a wireless manner (e.g., by radio frequency). The communication means of the implantable device 10 may be integrated into the housing 1.

[0075] method

[0076] According to a third aspect, a method for estimating a value representing a first pressure is provided, the first pressure being the pressure of the fluid in an expandable element 3 of an implantable medical device 10. The value enables estimation of the fluid pressure. It is particularly advantageous to estimate such a pressure in order to be alarmed when such a pressure is too high or too low. In particular, if the pressure of the fluid in the expandable element 3 is too high, this can cause damage to the tissue of the anatomical conduit surrounded by the expandable element 3. Conversely, if the pressure of the fluid in the expandable element 3 is too low, the anatomical conduit surrounded by the expandable element 3 is susceptible to being insufficiently closed, which in the example scenario where the conduit is the urethra can cause an incontinence episode.

[0077] Furthermore, the estimation of the value representative of the first pressure enables the estimation of the value representative of the atmospheric pressure to which the device 10 is subjected. As previously explained, variations in the atmospheric pressure may cause deformations of the reservoir 5 of the device 10. These deformations may lead to an uncontrolled injection of fluid into or extraction of fluid from the expandable element 3 and, therefore, to an increase or decrease in the pressure of the fluid in the expandable element 3.

[0078] Changes in atmospheric pressure or fluid pressure in the expandable element 3 are therefore phenomena that need to be monitored in order to avoid damage to the tissue of the dissection catheter or failure to close the dissection catheter.

[0079] The method described below comprises estimating a value representing a pressure. In particular, the estimated values ​​may, for example, comprise an estimate of a value representing a first pressure, a value representing a second pressure and also a value representing atmospheric pressure. The first pressure is the pressure of the fluid in the inflatable element 3 of the implantable medical device 10. The second pressure is the pressure of the fluid in the reservoir 5. Atmospheric pressure is the atmospheric pressure to which the device 10 and therefore the reservoir 5 is subjected. The value representing the pressure is a value that enables the pressure to be estimated, or, if there are several values ​​representing the pressure, a value that allows the changes in the pressure to be assessed. The value representing the pressure may be a value of an absolute pressure, for example expressed in Pascals. The value representing the pressure may also be a value of a force (for example a force applied to the reservoir 5 or to the inflatable element 3). The examples of values ​​representing the pressure proposed are not restrictive and one may envisage any other type of related value representing the pressure.

[0080] For the sake of brevity, in the rest of the specification, the concept of a value representing pressure will often be simply referred to as "pressure." For example, a value representing a first pressure will be referred to as "first pressure," but it will be understood that this expression "first pressure" means a value representing the first pressure.

[0081] Reference Figure 3The method for estimating a first pressure, namely the pressure of the fluid in the expandable element 3, comprises a step a) of determining a second pressure, namely the pressure of the fluid in the reservoir 5, implemented by the data control and processing unit 200. The second pressure will be written deuxième_P in the rest of the text.

[0082] According to an embodiment, the second pressure is determined based on at least one value measured by the reservoir sensor 102 and representative of the pressure of the fluid in the reservoir 5 .

[0083] Advantageously, the second pressure is the average or median of a plurality of values ​​representing the pressure of the fluid in the reservoir 5. In other words, a plurality of values ​​representing the pressure of the fluid in the reservoir 5 are acquired by the reservoir sensor 102 within a given time interval and an average or median is calculated based on the plurality of values ​​in order to acquire the second pressure. Still preferably, the second pressure is determined based on the average or median of at least three values ​​representing the pressure of the fluid in the reservoir 5. The median or average of a plurality of values ​​representing the pressure of the fluid in the reservoir 5 is written as M_means_P, and in a certain embodiment means_P is equivalent to M_means_P. In this case, the fact that the average or median of a plurality of values ​​of the pressure of the fluid in the reservoir 5 measured continuously over time is calculated makes it possible to evaluate the variation of the second pressure over time as a function of the variation of the atmospheric pressure. The resulting second pressure value is a smoothed value that takes into account the evolution of the pressure of the fluid in the reservoir 5 as a function of the variation of the atmospheric pressure. Preferably, the values ​​representing the pressure of the fluid in the reservoir 5 used for calculating the median or average are measured at intervals between 10 seconds and 8 minutes, preferably approximately equal to 2 minutes.

[0084] In order to estimate the second pressure in the most realistic and accurate way possible, different terms are advantageously calculated which are taken into account in the calculation of the second pressure.

[0085] In this respect, according to a preferred embodiment, the second pressure is based on a first change Δ representing the pressure of the fluid in the reservoir 5 caused by a change in volume of the reservoir 5 implemented by the actuator 8 of the device 10. pression More precisely, when the volume of the reservoir 5 is increased or decreased by the actuator 8 of the device 10, the change in the fluid pressure in the reservoir Δ pression This change Δ is estimated by measuring the fluid pressure in the reservoir 5 before and after the first change in volume of the reservoir 5 controlled by the actuator 8. pression In this embodiment, the second pressure deuxième P is equal to M_deuxièmes_P+Δ pression, i.e. the sum of the median or mean of the plurality of values ​​representative of the fluid pressure in the reservoir 5 and the value representative of the first variation in the fluid pressure in the reservoir 5. Thus, according to this embodiment, the estimate of the second pressure deuxième P takes into account the pressure variation caused by the last variation in the volume of the reservoir 5 that has been controlled by the actuator 8. The estimate of the second pressure is therefore an adapted / corrected estimate.

[0086] According to another preferred embodiment, the second pressure is based on a second variation Δ representing the pressure of the fluid in the tank 5 caused by a change in orientation of the device 10. Orientation Typically, the change in orientation of the device 10 may be caused by a change in the position or posture of the individual in which the device 10 is implanted. In the case of a person, for example, the change in orientation of the device 10 may be caused by a change in the person's position from standing to lying down or vice versa. The change in orientation of the device 10 may easily cause a change in the fluid pressure in the reservoir 5. For example, when a person lies down, the fluid pressure in the reservoir 5 may increase. Δ Orientation For example, it may be a value that changes when a change in the orientation of the device 10 is detected. For example, such a change in the orientation of the device may be automatically detected by means of a sensor, as described in document WO2021255388. In other scenarios, the individual may activate the "lie down" mode by pressing a suitable button of their external control element 9, and Δ Orientation will take on a different value than the previous value before the individual was activated in the "lie down" mode. The data control and processing unit 200 will then take into account Δ Orientation In this embodiment, the second pressure deuxième_P is equal to M_deuxièmes_P+Δ Orientation , which is the sum of the median or average of the plurality of values ​​representing the fluid pressure in the reservoir 5 and the value representing the second change in the fluid pressure in the reservoir 5 caused by the change in orientation of the device 10 .

[0087] If we consider the two embodiments described above, deuxime_P is expressed as M_deuximes_P+Δ pression +Δ Orientation It is understood that other terms may be considered to estimate the second pressure as close to reality as possible and the terms considered are not limited to those described.

[0088] refer to Figure 3 , the method for estimating the first pressure then comprises a step b) of estimating the first pressure based on the second pressure and on a parameter L depending on a value representing the maximum variation in the pressure of the fluid in the expandable element 3 caused by a variation in atmospheric pressure. In practice, preferably, the first pressure is based on the term deuxième_P L to calculate.

[0089] By way of example, the parameter L represents the fluid overpressure in the expandable element 3 due to the deformation of the reservoir 5 caused by the change in atmospheric pressure. In the event of a change in atmospheric pressure, the reservoir 5 tends to deform due to the elastic properties of some of its parts. This results in a change in the fluid pressure in the expandable element 3. Figure 4 The phenomenon that occurs when the atmospheric pressure to which the fluid of the reservoir 5 is subjected decreases is graphically shown. The flat dashed curve (first curve at the bottom of the graph) plots the evolution of the atmospheric pressure as a function of altitude. The more the altitude increases, the more the atmospheric pressure decreases. The dashed curve with squares (second curve from the bottom of the graph) plots the evolution of a second pressure as a function of altitude, i.e. the fluid pressure in the reservoir 5, for a reservoir 5 that does not deform despite changes in atmospheric pressure. The second curve shows an ideal scenario that does not reflect reality. In this case, the second pressure evolves in a linear manner and has the same guidance coefficient as the first curve showing the evolution of atmospheric pressure. The more the altitude increases, and therefore the atmospheric pressure decreases, the more the second pressure decreases in a linear manner. The dashed curve with squares (third curve from the bottom of the graph) plots the evolution of a second pressure as a function of altitude, i.e. the fluid pressure in the reservoir 5, for a reservoir 5 that deforms when the atmospheric pressure changes. This curve shows what really happens. It can be seen that the curve is non-linear and that the pressure of the fluid in the reservoir 5 does not drop as much as in the case of a reservoir 5 that is not deformed by changes in atmospheric pressure. This non-linearity of the curve is due to the fact that, when the atmospheric pressure decreases (i.e. the altitude increases), the reservoir 5 deforms so that its volume decreases, which affects the increase in the pressure of the fluid in the reservoir 5. The pressure of the fluid in the reservoir 5 therefore decreases less as a function of the decrease in atmospheric pressure than in the case of a non-deformable reservoir 5 shown in the third curve. At the same time, the decrease in the volume of the reservoir 5 causes the fluid to be injected from the reservoir 5 into the expandable element 3, which affects the increase in the pressure of the fluid in the expandable element 3. Therefore, the non-linearity of the third curve represents the overpressure of the fluid in the expandable element 3 and the greater the space between the second and third curves, the higher the overpressure of the fluid in the expandable element 3. The parameter L makes it possible to represent this non-linearity in a mathematical way.

[0090] For example, in the Figure 2 In the illustrated embodiment, the bellows 7 forms part of the wall of the variable volume reservoir. The bellows is formed by a plurality of coils which are elastically deformable. The bellows 7 may be in the shape of an organ bellows, the coils corresponding to the folds of the organ. In the static state, i.e. when the actuator 8 does not apply stress to change the volume of the reservoir, changes in atmospheric pressure lead to deformation of the coils, thereby changing the volume of the reservoir.

[0091] It is understood that the previous paragraph can also apply to the scenario of a decrease in altitude and thus an increase in atmospheric pressure. In this case, during the increase in atmospheric pressure, the reservoir 5 is deformed so that its volume increases, which affects a decrease in the pressure of the fluid in the reservoir 5. Therefore, the pressure of the fluid in the reservoir 5 increases less as a function of the decrease in atmospheric pressure than in the case where the reservoir 5 is not deformed. In parallel, the increase in the volume of the reservoir 5 draws fluid from the expandable element 3 into the reservoir 5, which affects a decrease in the pressure of the fluid in the expandable element 3.

[0092] The parameter L is a predetermined parameter and depends on various factors. The term "predetermined" should be understood to mean that the parameter is configured after the device 10 is implanted in an individual and is then not intended to be regularly modified, even if it is modifiable.

[0093] First, the parameter L depends on a value representing the maximum change in the pressure of the fluid in the expandable element 3 after a deformation of the reservoir 5 caused by a change in atmospheric pressure. In practice, this maximum change will be determined by empirical observation when the device 10 is implanted in an individual. More precisely, in order to simulate a reduction in atmospheric pressure, a fluid will be injected from the reservoir 5 into the expandable element 3. It can be considered, for example, that the maximum reduction in atmospheric pressure will be the maximum change in atmospheric pressure, which will be equivalent to an increase in altitude from 0 meters to 3000 meters above sea level. The volume of fluid intended to be injected from the reservoir 5 into the expandable element 3 after a deformation of the reservoir 5 caused by this reduction in atmospheric pressure is known and is injected into the expandable element 3. The pressure of the fluid in the expandable element 3 is then estimated. In this way, the maximum change in the pressure of the fluid in the expandable element 3 after a deformation of the reservoir 5 caused by a change in atmospheric pressure can be estimated. It should be noted that the parameter L can be obtained from a plurality of measurements of a value representing a third change in the pressure of the fluid in the reservoir 5 caused by one or more changes in atmospheric pressure. In other words, the calculation procedure described in this paragraph can be implemented for different simulations of atmospheric pressure changes.

[0094] The parameter L preferably also depends on the deformation rate of the reservoir 5. This rate is a quantity that indicates the deformability (or other elasticity) of the reservoir 5. This rate depends, among other things, on the component material or materials of the reservoir 5 and on the dimensions of the reservoir 5. In principle, two identical reservoirs 5 of the same material with the same dimensions must have the same deformation rate.

[0095] The parameter L may also depend on the size of the expandable element 3 .

[0096] As explained above, the first pressure depends on the second pressure together with the parameter L. More precisely, the first pressure depends on the term deuxième_P L .

[0097] Advantageously, the first pressure is estimated based on other quantities. In particular, the first pressure is preferably determined based on a reference second pressure deuxième_P_ref, which is determined based on the fluid pressure in the reservoir 5 measured by the reservoir sensor 102. The reference second pressure initially corresponds to a measurement taken by the reservoir sensor 102 before activation of the device 10. The reference second pressure corresponds to a reference value for the fluid pressure in the reservoir 5. The reference second pressure is advantageously updated periodically based on the measurement of the reservoir sensor 102. Preferably, the reference second pressure is updated at least once a day, preferably at least three times a day, and still preferably at least five times a day. It is understood here that the reference second pressure is updated less frequently than the median or average M_deuxièmes_P of multiple values ​​representing the fluid pressure in the reservoir 5. In fact, for the purpose of explanation, the second reference pressure is measured at time t0, while the value representing the measured fluid pressure in the reservoir 5 for calculation of the median or average value will be calculated at a different time t0+X minutes (or X seconds, X hours...). Then, if the median or average value is calculated based on four values ​​representing the fluid pressure in the reservoir 5, when eight values ​​representing the fluid pressure in the reservoir 5 are measured, the average or median value calculated based on the four first values ​​is updated and replaced by the average or median value calculated based on the four latest values. Moreover, from the time when the reference second pressure is measured (and the reference second pressure is thus updated), four new measured values ​​representing the value of the fluid pressure in the reservoir 5 will be measured to calculate the average or median value and thus update the previous average or median value.

[0098] In addition, preferably, the first pressure is determined based on the reference first pressure. The reference first pressure première_P_ref is determined based on the reference second pressure and based on the reference atmospheric pressure P_atm_ref measured by the barometer 90. Atmospheric pressure, the first pressure and the second pressure are considered to be mathematically related. Specifically, it is acceptable that première pressure=deuxième pressure-pressure atmosphérique. Therefore, it is understood that the reference first pressure can be estimated as a function of the reference second pressure and the reference atmospheric pressure. The reference atmospheric pressure is preferably measured automatically and periodically by the barometer 90 of the external control element 9 and / or when the individual requests via the external control element 9. Based on the second reference pressure and based on the reference atmospheric pressure, the reference first pressure is calculated as follows première_P_ref=deuxième_P_ref-P_atm_ref. Advantageously, the reference first pressure is updated at least once a day. This logically implies that the reference second pressure and the reference atmospheric pressure are updated at least once a day. Alternatively, the reference first pressure is not measured and corresponds to a predetermined value.

[0099] Finally, advantageously, the first pressure is calculated by the control and processing unit based on the following formula:

[0100]

[0101] Preferably, degree_P=M_degrees_P+Δ pression +Δ Orientation .

[0102] Thus, the first pressure, ie the pressure of the fluid in the inflatable element 3, is estimated by the control and processing unit. This makes it possible, for example, to compare this estimate with one or more threshold values ​​for the first pressure in order to determine whether the first pressure is less than or greater than a certain threshold value, which would be synonymous with danger or discomfort for the individual in whom the device 10 is implanted.

[0103] According to a fourth aspect, a method for estimating the atmospheric pressure experienced by an implantable medical device 10 is provided. Figure 5 , this second method firstly comprises the method described above for estimating the first pressure.

[0104] The second method also comprises a step c) of estimating the atmospheric pressure by subtracting the first pressure from the second pressure. Given that the second pressure and the first pressure are already obtained, it is sufficient to calculate the following subtraction deuxième_P-première_P to obtain the atmospheric pressure to which the device 10 is subjected. As explained, variations in the atmospheric pressure may cause deformations of the reservoir 5 and therefore variations in the first pressure, ie the pressure of the fluid in the expandable element 3. The fact that the atmospheric pressure can be calculated makes it possible to detect variations in the atmospheric pressure. A procedure for compensating for such variations in the atmospheric pressure can then be implemented.

[0105] Program product and storage device

[0106] According to a fifth aspect, a computer program product is provided, comprising code instructions for executing a method for estimating a value representative of a first pressure and a method for estimating a value representative of atmospheric pressure when said program is executed by an electronic control unit.

[0107] According to a sixth aspect, there is provided a storage device readable by a piece of computer equipment, a computer program product thereon comprising code instructions for executing a method for estimating a value representative of a first pressure and a method for estimating a value representative of atmospheric pressure.

[0108] The invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications are still possible, in particular from the point of view of the composition of the various technical features or by replacement by technical equivalents, without departing from the general teaching.

Claims

1. A method for estimating a value representative of a first pressure, the first pressure being the pressure of a fluid in an expandable element (3) of an implantable medical device (10), the implantable medical device (10) comprising a selectively variable volume fluid reservoir (5), the reservoir (5) being deformable under the effect of atmospheric pressure variations, the expandable element (3) being fluidically connected to the reservoir (5), the method comprising the following steps implemented by a data control and processing unit (200) of the device: a) determining a value representing a second pressure, said second pressure being the pressure of the fluid in said reservoir (5), b) estimating a value representative of the first pressure based on the value representative of the second pressure and based on a parameter (L) dependent on a value representative of the maximum change in fluid pressure in the expandable element (3) caused by a change in atmospheric pressure.

2. The estimation method according to claim 1, wherein: The value representative of the second pressure is determined based on at least one value representative of the pressure of the fluid in the reservoir (5) measured by a sensor (102) included in the implantable medical device.

3. The estimation method according to claim 2, wherein: The value representing the first pressure is determined based on a value representing a reference second pressure, which is determined based on a value representing the pressure of the fluid in the reservoir (5) measured by the sensor (102).

4. The estimation method according to claim 3, wherein: The value representing the first pressure is determined based on a value representing a reference first pressure, which is determined based on a value representing the reference second pressure measured by the sensor (102) and based on a value representing a reference atmospheric pressure measured by a barometer (90).

5. The estimation method according to claim 4, wherein: The barometer (90) is arranged on the outer wall of the box body 1 or inside the box body 1.

6. The estimation method according to claim 4, wherein: The barometer (90) is included in an external control element (9) suitable for exchanging data with the implanted medical device, and wherein the value representative of the reference atmospheric pressure is measured following a command implemented via the external control element (9) by an individual in whom the device is implanted.

7. The estimation method according to claim 4, wherein: The value representing the reference first pressure is updated based on the updated value representing the reference atmospheric pressure and the updated value representing the reference second pressure each time the command is implemented.

8. The estimation method according to claim 4, wherein: The value representing the reference first pressure is updated at least once a day based on the updated value representing the reference atmospheric pressure and based on the updated value representing the reference second pressure.

9. The estimation method according to claim 3, wherein: The value representing the reference second pressure is updated at least once a day, preferably at least three times a day, still preferably at least five times a day.

10. The estimation method according to claim 1, wherein: The value representing the second pressure is an average or median of a plurality of values ​​representing the pressure of the fluid in the reservoir (5).

11. The estimation method according to claim 10, wherein: The value representing the second pressure is determined based on an average or median value of at least three values ​​representing the pressure of the fluid in the reservoir (5).

12. The estimation method according to claim 1, wherein: The value representing the second pressure is determined based on a value representing a first change in pressure of the fluid in the reservoir (5) caused by a change in volume of the reservoir (5) implemented by an actuator (8) of the device (10).

13. The estimation method according to claim 1, wherein: The value representing the second pressure is determined based on a value representing a second change in pressure of the fluid in the reservoir (5) caused by a change in orientation of the device.

14. The estimation method according to claim 1, wherein: The value representing the first pressure is calculated based on: [Mathematical formula 1] second_P L deuxième_P is a value representing the second pressure, and L is the parameter that depends on the maximum change in pressure in the inflatable element (3) caused by a change in atmospheric pressure.

15. The estimation method according to claim 1, wherein: The parameter (L) is previously obtained based on one or more measurements of a value representative of a third variation in the pressure of the fluid in the reservoir (5) caused by one or more variations in the atmospheric pressure.

16. The estimation method according to one of claims 1 to 15, wherein: The value representing the first pressure is determined by calculating: [Mathematical formula 2] première_P_ref is a value representing a reference first pressure, and deuxième_P_ref is a value indicating a reference second pressure.

17. A method for estimating a value representative of the atmospheric pressure to which an implantable medical device is subjected, comprising the estimation method according to one of claims 1 to 16 and comprising a step c) of estimating the value representative of the atmospheric pressure by subtracting the value representative of the second pressure from the value representative of the first pressure.

18. An implantable medical device (10) comprising a variable volume fluid reservoir (5), an expandable element (3) fluidically connected to the reservoir (5) and a data control and processing unit, the unit being configured to implement the method according to one of claims 1 to 17.

19. The implantable medical device (10) according to claim 18 is configured to be implanted in a human or animal body to selectively close an anatomical conduit of the human or animal body, the anatomical conduit being taken from at least one of the following conduits: urethra, gastric tube, colon and rectum.

20. The implantable medical device (10) of claim 19, comprising an elongated shaped expandable element (3) configured for use as a penile implant.

21. An assembly comprising an implantable medical device according to one of claims 18 to 20 and an external control element (9) adapted to exchange data with the implantable medical device and to be used by an individual in whom the medical device is implanted, wherein The implantable medical device and the external control element (9) comprise communication means for communicating with each other.

22. A computer program product comprising code instructions for performing the method according to one of claims 1 to 17 when said program is executed by an electronic control unit.

23. A storage device readable by a piece of computer equipment, on which a computer program product comprises code instructions for executing the method as claimed in one of claims 1 to 17.

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