Method for estimating a value representative of a fluid pressure in an inflatable element of an 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 inflatable element (3) of an implantable medical device (10) comprising a fluid reservoir (5) having a selectively variable volume, the reservoir (5) being able to deform under the effect of a variation in atmospheric pressure, and the inflatable element (3) being in fluid communication with the reservoir (5). The method comprises the steps, implemented by a data processing and control unit (200) of the device, of: a) determining a value representative of a second pressure, the second pressure being a fluid pressure in the reservoir (5); b) estimating the value representative of the first pressure from the value representative of the second pressure and from a parameter (L) that is dependent on a value representative of a maximum variation in fluid pressure in the inflatable element (3) caused by a variation in atmospheric pressure.

Description

[0001] Method for estimating a representative value of a fluid pressure in an inflatable element of an implantable medical device

[0002] GENERAL TECHNICAL FIELD The present invention relates to a method for estimating a value representative of a fluid pressure in an inflatable element of an implantable medical device comprising a fluid reservoir with selectively variable volume.

[0003] STATE OF THE ART Medical devices are in the form of systems that can be implanted in the body of a human or animal individual. In particular, such devices may correspond to artificial urinary sphincters used to combat urinary incontinence, gastric bands or rings adapted to restrict the stomach in order to combat obesity, inflatable penile implants used for erectile prostheses, etc.

[0004] In a manner known per se, the implantable system may be hydraulically operated and may include in particular a variable volume fluid reservoir and an inflatable element containing a variable volume of fluid. The inflatable element is in fluid connection with the variable volume fluid reservoir, so as to be able to transfer fluid from the reservoir to the inflatable element, and vice versa.

[0005] In the case of an implantable occlusive system such as an artificial urinary sphincter, the inflatable element is an inflatable occlusive cuff capable of selectively occluding an anatomical conduit such as a urethra in men, or a bladder neck in women. Fluid can be transferred from the reservoir to the cuff to increase the pressure exerted on the conduit, and vice versa from the cuff to the reservoir to reduce the pressure exerted on the conduit. Thus, depending on the volume of fluid in the cuff, more or less pressure can be exerted on the anatomical conduit to be occluded.

[0006] Elements of the implantable fluid system may be sensitive to variations in atmospheric pressure (for example due to variations in altitude) and may deform. For example, the reservoir of the implantable fluid system may comprise an elastically deformable portion that deforms according to variations in atmospheric pressure. This deformation may result in an uncontrolled injection of fluid into the cuff or extraction of fluid from the cuff and therefore an increase or decrease in the fluid pressure in the cuff. However, such variations in fluid pressure in the cuff must be avoided. In the case of artificial urinary sphincters, excess pressures are likely to damage the tissues around which the cuff is arranged, for example by causing damage to these tissues. It is therefore necessary to control these excess pressures in order to limit the corresponding risk of tissue damage.This involves being able to estimate the pressure variations in the inflatable element in order to then possibly compensate for them. DISCLOSURE OF THE INVENTION.

[0007] An aim of the invention is to reliably calculate the fluid pressure in the inflatable element of an implantable medical device.

[0008] Another aim of the invention is to reliably calculate the atmospheric pressure to which the implantable medical device is subjected.

[0009] The present invention thus relates, according to a first aspect, to a method for estimating a value representative of a first pressure, the first pressure being a fluid pressure in an inflatable element of an implantable medical device comprising a fluid reservoir with selectively variable volume, the reservoir being capable of deforming under the effect of a variation in atmospheric pressure, the inflatable element in fluid connection with said reservoir, comprising the steps implemented by a control and data processing unit of the device of: a) determining a value representative of a second pressure, the second pressure being a fluid pressure in the reservoir,b) estimation of the representative value of the first pressure from the representative value of the second pressure and a parameter dependent on a value representative of a maximum variation in fluid pressure in the inflatable element caused by a variation in atmospheric pressure.,

[0010] According to advantageous and non-limiting characteristics, taken alone or in any combination: - the representative value of the second pressure is determined from at least one representative value of the fluid pressure in the reservoir measured by a sensor included in the implantable medical device; the representative value of the first pressure is determined from a representative value of the second reference pressure determined from a representative value of the fluid pressure in the reservoir measured by the sensor; the representative value of the first pressure is determined from a representative value of a first reference pressure, the representative value of the first reference pressure being determined from the representative value of the second reference pressure measured by the sensor and from a representative value of reference atmospheric pressure measured by a barometer;said barometer is arranged on an external wall of the housing 1 or in the housing 1; said barometer is included in an external control element adapted to exchange data with the implantable medical device and in which the representative value of reference atmospheric pressure is measured following a command implemented by an individual in whom the device is implanted via the external control element; - the representative value of first reference pressure is updated each time a command is implemented from an updated representative value of reference atmospheric pressure and a representative value of second reference pressure; - the representative value of first reference pressure is updated at least once a day from an updated representative value of reference atmospheric pressure and the representative value of second reference pressure;the representative value of the second reference pressure is updated at least once a day, preferably at least three times a day, more preferably at least five times a day; the representative value of the second pressure is an average or a median of a plurality of values ​​representative of the fluid pressure in the reservoir; - the representative value of the second pressure is determined from an average or a median of at least three values ​​representative of the fluid pressure in the reservoir; the representative value of the second pressure is determined from a value representative of a first variation in fluid pressure in the reservoir caused by a variation in the volume of the reservoir implemented by an actuator of the device;the representative value of the second pressure is determined from a representative value of a second variation in fluid pressure in the reservoir caused by a change in orientation of the device; the representative value of the first pressure is calculated from the following term: second_P; L second_P being the representative value of the second pressure and L being said parameter dependent on the maximum pressure variation in the inflatable element caused by the variation in atmospheric pressure; said parameter is obtained beforehand from one or more measurements of a value representative of a third variation in a fluid pressure in the tank caused by one or more variations in atmospheric pressures; the representative value of the first pressure is determined by calculating: second _P_ref L

[0011] - - - ; - - — x first_P_ref second_P Lfirst e_P_ref being a representative value of first reference pressure and second_P_ref being a representative value of second reference pressure.

[0012] According to a second aspect, the invention relates to a method for estimating a value representative of an atmospheric pressure to which an implantable medical device is subjected, comprising the estimation method presented previously, and comprising a step c) of estimating the value representative of an atmospheric pressure by subtracting the value representative of the second pressure from the value representative of the first pressure.

[0013] According to a third aspect, the invention relates to an implantable medical device comprising a variable-volume fluid reservoir, an inflatable element in fluid connection with said reservoir and a data control and processing unit, said unit being configured to implement the estimation methods presented previously. According to advantageous and non-limiting characteristics, taken alone or in any combination: the device is configured to be implanted in a human or animal body to selectively close an anatomical duct of said human or animal body taken from at least one of the following ducts: a urethra, a gastric duct, a colon and a rectum; the device comprises an elongated inflatable element configured to be used as a penile implant.According to a fourth aspect, the invention relates to an assembly comprising an implantable medical device presented previously and an external control element adapted to exchange data with the implantable medical device and adapted to be used by an individual in whom the medical device is implanted, in which the implantable medical device and the external control element comprise communication means adapted to communicate with each other.

[0014] According to a fifth aspect, the invention relates to a computer program product comprising code instructions for the execution of a method presented previously, when said program is executed by a computer.

[0015] According to a sixth aspect, the invention relates to a storage means readable by computer equipment on which a computer program product comprises code instructions for the execution of a method presented previously.

[0016] DESCRIPTION OF FIGURES

[0017] Other characteristics and advantages of the present invention will appear on reading the following description of a preferred embodiment. This description will be given with reference to the appended figures, of which: Figure 1 illustrates an overall view of a medical device implantable in the body of an individual and of a control element external to the body of the individual. Figure 2 is a schematic sectional view of the interior of the housing according to one embodiment;

[0018] Figure 3 represents the steps of the method for estimating a first pressure;

[0019] Figure 4 is a graph representing revolutions of different pressures as a function of an increase in altitude; - Figure 5 represents the steps in the process of estimating atmospheric pressure.

[0020] DETAILED DESCRIPTION OF THE INVENTION

[0021] Device According to a first aspect, a medical device is proposed that can be implanted in an individual. In this text, the term "individual" means a human being or an animal. The device is an active implantable medical device capable of occluding a natural conduit such as, for example, a urethra (in men), the bladder neck (in women), a gastric conduit, a colon or even a rectum. In the case of application to a urethra or a bladder body, the device makes it possible in particular to combat 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 pressure variations, in particular generated by altitude variations. Other forms that the device can take include penile implants and gastric constriction bands.A medical device implantable in a human or animal body is illustrated by way of non-limiting example in Figures 1 and 2.

[0022] The implantable device 10 comprises:

[0023] - a sealed housing 1 containing a gas, - an inflatable element 3 adapted to be implanted in the body of the individual outside the housing,

[0024] - a fluid circuit comprising a fluid reservoir 5 having a variable fluid volume arranged in the housing and a fluid connection 2 between said reservoir 5 and said inflatable element 3,

[0025] - an actuator 8 arranged in the housing 1 and mechanically coupled to a part of the fluid reservoir 5 to selectively vary the volume of fluid in said reservoir,

[0026] - a control unit 100 configured to control the actuator 8 so as to transfer fluid between the reservoir 5 and the inflatable element 3,

[0027] - a data control and processing unit 200 configured to implement a method for estimating a value representative of a fluid pressure in the inflatable element 3 called “first pressure”. The fluid circuit is adapted to be filled with a fluid. A variation in the volume of the reservoir 5 causes a variation in the pressure in the fluid circuit. More particularly, a reduction in the volume of the reservoir 5 causes a transfer of fluid from the reservoir 5 to the inflatable 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 inflatable element 3 to the reservoir 5, and causes a reduction in the pressure in the fluid circuit.

[0028] The reservoir 5 is preferably a fluid reservoir with a variable volume capable of deforming under the effect of a variation in atmospheric pressure. The reservoir 5 may therefore comprise an elastically deformable part which deforms according to variations in atmospheric pressure. This deformation may cause a variation in the volume of the reservoir 5 and therefore transfers of fluid between the reservoir 5 and the inflatable element 3.

[0029] The reservoir 5 further comprises an orifice for transferring the fluid from the reservoir 5 to the inflatable element 3 via the fluid connection 2 or from the inflatable element 3 to the reservoir 5 via the fluid connection 2.

[0030] 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 2 opens into the inflatable element 3.

[0031] The inflatable element 3 may be an inflatable occlusive cuff, particularly when the device 10 is an artificial urinary sphincter. The fluid-filled inflatable occlusive cuff 3 may be adapted to completely or partially surround the duct to be occluded.

[0032] Alternatively, the inflatable element 3 may be an inflatable penile implant, and thus have an elongated shape, in particular when the device 10 is an erectile prosthesis.

[0033] The housing 1, the fluid connection 2 and the inflatable element 3 are adapted to be implanted in the body of an individual I, the contours of which are shown schematically in Figure 1 on either side of this assembly. The housing 1, in particular the interior volume 11 of the housing 1 surrounding the reservoir

[0034] 5, contains a gas, for example an inert gas.

[0035] The actuator 8 is adapted to control a variation in the volume of the reservoir 5. The actuator 8 is controlled by the control unit 100. In a certain embodiment, the actuator 8 is adapted to control a linear displacement of the movable wall 6, the bellows 7 being adapted to expand or compress as a function of said linear displacement of the movable wall 6 controlled by the actuator 8.

[0036] The actuator 8 may be chosen from any electromechanical system making it possible to transform electrical energy into a mechanical movement with the power required to enable the movement at a required force and speed of the movable wall 6 of the variable-volume tank 5. The actuator 8 may in particular be a piezoelectric actuator, an electromagnetic actuator which may comprise an electromagnetic motor with or without brushes coupled or not to a reducer, an electroactive polymer or a shape memory alloy. The control unit 100 is configured to control the actuator 8 so as to move the movable wall 6 of the tank 5 to a position corresponding to the determined volume. More particularly, in the example illustrated in FIG. 2, the control unit 100 is adapted to issue an operating command for a motor of the actuator 8 in one direction or the other depending on whether an increase or a decrease in the volume of the tank 5 is required.

[0037] Advantageously, the housing 1 contains a reservoir sensor 102 adapted to measure a value representative of the fluid pressure in the reservoir 5 called “second pressure”. The reservoir sensor 102 can for example be a force sensor or a pressure sensor.

[0038] Particularly advantageously, an external control element 9, such as a remote control, external to the patient's body, can be used by the patient or a third party to communicate wirelessly with the medical device 10, for example by radio frequencies.

[0039] 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 an external wall of the housing 1 and is configured to communicate with the device 10. According to yet another embodiment, the barometer 90 may be arranged in the external control element 9 external to the body of the individual in which the device 10 is implanted. The barometer 90 is adapted to measure a value representative of an atmospheric pressure to which the implantable medical device 10 is subjected. In the case of a barometer 90 arranged in the external control element 9, a measurement of a value representative of the atmospheric pressure may thus be carried out via the external control element 9, for example when the patient himself activates a command of the external control element 9.

[0040] Alternatively or in combination, the barometer 90 may also be configured to implement an atmospheric pressure measurement at a predetermined frequency.

[0041] Together

[0042] According to a second aspect, there is provided an assembly comprising an implantable medical device 10 as described above, and an external control element 9 adapted to be used by an individual, for example by an individual in whom the system is implanted. The implantable medical device 10 and the external control element 9 comprise communication means adapted to communicate with each other wirelessly, for example by radio frequencies. The communication means of the implantable device 10 may be integrated into the housing 1.

[0043] Methods According to a third aspect, a method is proposed for estimating a value representative of a first pressure, the first pressure being a fluid pressure in the inflatable element 3 of the implantable medical device 10. This value makes it possible to estimate the fluid pressure. It is particularly interesting to estimate this pressure in order to be alerted when this pressure is too high or too low. Indeed, if the fluid pressure in the inflatable element 3 is too high, this can cause damage to the tissues of the anatomical conduit that the inflatable element 3 surrounds. Conversely, if the fluid pressure in the inflatable element 3 is too low, the anatomical conduit surrounded by the inflatable element 3 is likely not to be sufficiently closed, which can cause, in the example case where the conduit is a urethra, an episode of incontinence.

[0044] Furthermore, the estimation of a value representative of the first pressure makes it possible to estimate a value representative of the atmospheric pressure to which the device 10 is subjected. As explained previously, a variation in atmospheric pressure can cause deformations of the reservoir 5 of the device 10. These deformations can lead to an injection of fluid into the inflatable element 3 or an extraction of fluid from the inflatable element 3 in an uncontrolled manner and therefore an increase or a decrease in the fluid pressure in the inflatable element 3.

[0045] Variations in atmospheric pressure or fluid pressure in the inflatable element 3 are therefore phenomena to be monitored to avoid damage to the tissues of the anatomical conduit or lack of sealing of the anatomical conduit.

[0046] The methods described below comprise the estimation of representative pressure values. In particular, among the estimated values ​​are for example estimated a representative first pressure value, a representative second pressure value as well as a representative atmospheric pressure value. The first pressure is a fluid pressure in the inflatable element 3 of the implantable medical device 10. The second pressure is a fluid pressure in the reservoir 5. The atmospheric pressure is the atmospheric pressure to which the device 10 and therefore the reservoir 5 is subjected. A representative pressure value is a value which makes it possible to estimate the pressure or which makes it possible, if several representative pressure values ​​are available, to evaluate variations in the pressure. A representative pressure value may be an absolute pressure value expressed for example in Pascal.A representative pressure value may also be a force value (e.g. a force exerted on the tank 5 or the inflatable element 3). The examples of representative pressure values ​​provided are not limiting and any other type of relevant representative pressure values ​​could be considered.

[0047] For the sake of brevity, in the remainder of the description, the notions of representative pressure values ​​will regularly be simply called "pressures". For example, the representative value of first pressure will be called "first pressure", but it will be understood that this expression "first pressure" designates the representative value of first pressure.

[0048] With reference to Figure 3, the method for estimating the first pressure, i.e. the fluid pressure in the inflatable element 3, comprises a step a), implemented by the control and data processing unit 200, of determining a second pressure, i.e. the fluid pressure in the reservoir 5. The second pressure will be denoted second_P in the following.

[0049] According to one embodiment, the second pressure is determined from at least one value representative of the fluid pressure in the tank 5 measured by the tank sensor 102.

[0050] Advantageously, the second pressure is an average or a median of a plurality of values ​​representative of the fluid pressure in the reservoir 5. In other words, a plurality of values ​​representative of the fluid pressure in the reservoir 5 are acquired by the reservoir sensor 102 over a given time range and an average or a median is calculated from the plurality of values ​​in order to obtain the second pressure. More preferably, the second pressure is determined from an average or a median of at least three values ​​representative of the fluid pressure in the reservoir 5. The median or the average of the plurality of values ​​representative of the fluid pressure in the reservoir 5 is denoted M_second_P and, in a certain embodiment, second_P corresponds to M_second_P.In this case, calculating an average or a median of several values ​​representative of the fluid pressure in the tank 5 measured successively over time makes it possible to evaluate the second pressure over time as a function of variations in atmospheric pressure. The resulting second pressure value is a smoothed value which takes into account the change in the fluid pressure in the tank 5 as a function of variations in atmospheric pressure. Preferably, the values ​​representative of the fluid pressure in the tank 5 used to calculate the median or the average are measured at intervals of between 10 seconds and 8 minutes, preferably approximately equal to 2 minutes. In order to estimate the second pressure as realistically and accurately as possible, different terms are advantageously calculated which are taken into account in the calculation of the second pressure.

[0051] In this respect, according to a preferred embodiment, the second pressure is determined from a value representative of a first variation in fluid pressure in the reservoir 5 ^pressure caused by a variation in the volume of the reservoir 5 implemented by an actuator 8 of the device 10. More precisely, when an increase or a decrease in the volume of the reservoir 5 controlled by the actuator 8 of the device 10 is implemented, a variation in fluid pressure in the reservoir 5 pressiontakes place. The variation ^pressure is estimated by measuring the fluid pressure in the reservoir 5 before and after the last variation in volume of the reservoir 5 controlled by the actuator 8. In this embodiment, the second pressure second P corresponds to M_deuxlèmes_P + ^pressure, that is to say the sum of the median or the average of the plurality of values ​​representative of the fluid pressure in the reservoir 5 and of the value representative of the first variation in fluid pressure in the reservoir 5. Thus, according to this embodiment, the estimation of the second pressure second P takes into account the pressure variation which was caused by the last variation in volume of the reservoir 5 controlled by the actuator 8. The estimation of the second pressure is thus an adapted / corrected estimation.

[0052] According to another preferred embodiment, the second pressure is determined from a value representative of a second variation in fluid pressure in the reservoir 5 ^orientation caused by a change in orientation of the device 10. Typically, a change in orientation of the device 10 may be caused by a change in position or posture of the individual in which the device 10 is implanted. In the case of a human for example, a change in orientation of the device 10 may be caused by the change in the position of the human from standing to lying down or vice versa. A change in orientation of the device 10 is likely to cause a variation in fluid pressure in the reservoir 5. For example, when a human lies down, the fluid pressure in the reservoir 5 will increase. ^orientation may for example be a value that changes when a change in orientation of the device 10 is detected.For example, such a change in orientation of the device can be detected automatically by means of sensors, as described in document WO2021255388. In other cases, the individual can himself activate a “lying” mode by pressing a suitable button on his external control element 9 and ^orientation will take a different value from the previous one, before the individual activates the “lying” mode. The control and data processing unit 200 will then take into account ^orientation • In this embodiment, the second pressure second_P corresponds to M_seconds_P + ^orientation, that is to say the sum of the median or the average of the plurality of values ​​representative of the fluid pressure in the reservoir 5 and of the value representative of the second variation in fluid pressure in the reservoir 5 caused by a change in orientation of the device 10.

[0053] If we consider the two previous embodiments described, deuxlème_P is expressed M_deuxlèmes_P + à pression + ^orientation - It is understood that other terms can be taken into account to estimate the second pressure as close to reality as possible and that the terms taken into account are not limited to those described.

[0054] With reference to Figure 3, the method for estimating the first pressure then comprises a step b) of estimating the first pressure from the second pressure and a parameter L depending on a value representative of a maximum variation in fluid pressure in the inflatable element 3 caused by a variation in atmospheric pressure. In fact, preferably, the first pressure is calculated from the term second_P L .

[0055] For illustration purposes, the parameter L is representative of the excess fluid pressure in the inflatable element 3 due to a deformation of the reservoir 5 caused by a variation in atmospheric pressure. During a variation in atmospheric pressure, the reservoir 5 is likely to deform due to the elastic properties of some of its parts.

[0056] This causes a variation in the fluid pressure in the inflatable element 3. Figure 4 graphically illustrates the phenomenon that occurs when the atmospheric pressure to which the fluid in the reservoir 5 is subjected decreases. The single dotted curve (first curve from the bottom of the graph) plots the evolution of the atmospheric pressure as a function of altitude. The higher the altitude, the more the atmospheric pressure decreases. The dotted curve with squares (second curve from the bottom of the graph) plots the evolution of the second pressure, namely the fluid pressure in the reservoir 5, as a function of altitude, for a reservoir 5 that does not deform despite variations in atmospheric pressure. This second curve illustrates an ideal case that does not reflect reality.In this case, the second pressure evolves linearly and has the same slope as the first curve, which illustrates the evolution of atmospheric pressure. The higher the altitude, and therefore the lower the atmospheric pressure, the more the second pressure decreases linearly. The dashed curve with squares (third curve from the bottom of the graph) plots the evolution of the second pressure, namely the fluid pressure in tank 5, as a function of altitude, for a tank 5 that deforms when atmospheric pressure changes. This curve illustrates what actually happens. We then notice that this curve is not linear and the fluid pressure in tank 5 does not decrease as much as in the case of a tank 5 that does not deform due to atmospheric pressure changes.

[0057] This non-linearity of the curve is due to the fact that, when the atmospheric pressure decreases (i.e., increase in altitude), the tank 5 deforms so that its volume decreases, which is a factor in an increase in fluid pressure in the tank 5. The fluid pressure in the tank 5 therefore decreases less as a function of the decrease in atmospheric pressure than if the tank 5 were not deformable, as illustrated by the third curve. In parallel, the decrease in the volume of the tank 5 causes an injection of fluid from the tank 5 towards the inflatable element 3, which is a factor in an increase in fluid pressure in the inflatable element 3. Thus, the non-linearity of the third curve is representative of an overpressure of the fluid in the inflatable element 3, and the greater the space between the second and third curves, the greater the overpressure of the fluid in the inflatable element 3.The parameter L makes it possible to represent this non-linearity mathematically.

[0058] For example, in the embodiment illustrated in Figure 2, the bellows 7 forms a portion of the wall of the variable-volume tank. The bellows is formed from a plurality of convolutions, which may be elastically deformable. The bellows 7 may be in the form of an accordion bellows, the convolutions corresponding to folds of the accordion. In static conditions, that is to say when no stress is exerted by the actuator 8 to vary the volume of the tank, a variation in atmospheric pressure may cause a deformation of the convolutions, thus varying the volume of the tank. It is understood that the preceding paragraph could be applied reciprocally to a case of decrease in altitude and therefore increase in atmospheric pressure. In this case, when the atmospheric pressure increases, the tank 5 deforms so that its volume increases, which is a factor in a decrease in fluid pressure in the tank 5.The fluid pressure in the reservoir 5 therefore increases less as a function of the decrease in atmospheric pressure than if the reservoir 5 were not deformable. At the same time, the increase in the volume of the reservoir 5 causes fluid to be drawn from the inflatable element 3 towards the reservoir 5, which is a factor in a decrease in fluid pressure in the inflatable element 3.

[0059] The parameter L is a predetermined parameter and depends on various factors. By predetermined, we mean that it is configured following the implantation of the device 10 in an individual and that it is not intended to be modified regularly even if it is modifiable. First of all, the parameter L depends on a value representative of a maximum variation in fluid pressure in the inflatable element 3 following a deformation of the reservoir 5 caused by a variation in atmospheric pressure. In practice, this maximum variation will be determined empirically when the device 10 is implanted in an individual. More precisely, to simulate a decrease in atmospheric pressure, fluid will be injected from the reservoir 5 into the inflatable element 3.For example, it may be considered that the maximum decrease in atmospheric pressure will be the maximum variation in atmospheric pressure that will be equivalent to an increase in altitude from 0 meters to 3000 meters above sea level. The volume of fluid that is supposed to be injected into the inflatable element 3 from the reservoir 5 following a deformation of the reservoir 5 caused by this decrease in atmospheric pressure is known and is injected into the inflatable element 3. An estimate of the fluid pressure in the inflatable element 3 is then made. Thus, the maximum variation in fluid pressure in the inflatable element 3 following a deformation of the reservoir 5 caused by a variation in atmospheric pressure is estimated.It should be noted that the parameter L can be obtained from a plurality of measurements of a value representative of a third variation of a fluid pressure in the tank 5 caused by one or more variations in atmospheric pressures. In other words, the calculation procedure described in this paragraph can be implemented for different atmospheric pressure variation simulations. The parameter L preferably also depends on a deformation rate of the tank 5. This rate is a quantity representative of the deformability (or elasticity) of the tank 5. This rate depends, among other things, on the material(s) making up the tank 5 and on the size of the tank 5. In principle, two identical tanks 5 having the same materials and the same size should have an identical deformation rate.

[0060] The parameter L may also depend on the size of the inflatable element 3.

[0061] As explained previously, the first pressure depends on the second pressure as well as the parameter L. More precisely, the first pressure depends on the term second_P L .

[0062] Advantageously, the first pressure is estimated from other quantities. Indeed, the first pressure is preferably determined from a second reference pressure _P_ref determined from a fluid pressure in the tank

[0063] 5 measured by the tank sensor 102. The second reference pressure initially corresponds to a measurement made by the tank sensor 102 before activation of the device 10. The second reference pressure corresponds to a reference value of the fluid pressure in the tank 5. The second reference pressure is advantageously updated periodically from measurements of the tank sensor 102. Preferably, the second reference pressure is updated at least once a day, preferably at least three times a day, more preferably at least five times a day. It is understood here that the second reference pressure is updated less frequently than the median or the average of the plurality of values ​​representative of the fluid pressure in the tank 5 M_seconds_P.In fact, for illustration purposes, the second reference pressure is measured at a time to while the representative values ​​of the fluid pressure in the tank 5 measured for the calculation of the median or the average will be calculated at different times to + X minutes (or X seconds, X hours...). Then, if the median or the average is calculated from four representative values ​​of the fluid pressure in the tank 5, when eight representative values ​​of the fluid pressure in the tank 5 are measured, the average or the median which had been calculated from the first four values ​​is updated and replaced by the average or the median which is calculated from the four most recent values.Furthermore, from the instant at which a second reference pressure is measured (therefore the second reference pressure is updated), four new measurements of values ​​representative of the fluid pressure in the tank 5 will be measured to calculate the average or the median and thus update the previous average or median value. Furthermore, preferably, the first pressure is determined from a first reference pressure. The first reference pressure first e_P_ref is determined from the second reference pressure and a reference atmospheric pressure P_atm_ref measured by the barometer 90. Atmospheric pressure, first pressure and second pressure are considered to be mathematically linked. Indeed, it is accepted that first pressure = second pressure - atmospheric pressure.Accordingly, it is understood that the first reference pressure can be estimated as a function of the second reference pressure and a reference atmospheric pressure. The reference atmospheric pressure is preferably measured by the barometer 90 of the external control element 9 automatically periodically and / or when the individual requests it via the external control element 9. From the second reference pressure and the reference atmospheric pressure, the first reference pressure is calculated as follows: first_P_ref = second_P_ref — P_atm_ref. Advantageously, the first reference pressure is updated at least once a day. This logically implies that the second reference pressure and the reference atmospheric pressure are updated at least once a day. Alternatively, the first reference pressure is not measured and corresponds to a predetermined value.

[0064] Finally, advantageously, the first pressure is calculated by the control and processing unit from the following formula: second _P_ref L

[0065] — - - ; - — x first e_P_ref . second_P L

[0066] Preferably, second_P = M_second_P + to pression + orientation.

[0067] Thus, the first pressure, i.e. the fluid pressure 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 first pressure thresholds in order to determine whether the first pressure is lower or higher than a certain threshold, which would be synonymous with danger or inconvenience for the individual in whom the device 10 is implanted. According to a fourth aspect, a method is proposed for estimating an atmospheric pressure to which the implantable medical device 10 is subjected. With reference to FIG. 5, this second method firstly comprises the method for estimating the first pressure presented above. The second method further 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 have been obtained, it is sufficient to calculate the following subtraction second_P — first_P to obtain the atmospheric pressure to which the device 10 is subjected. As explained, variations in atmospheric pressure can cause deformation of the reservoir 5 and thus cause variations in the first pressure, i.e. fluid pressure in the inflatable element 3. Being able to calculate the atmospheric pressure makes it possible to be able to detect a variation in atmospheric pressure. Procedures for compensating for this variation in atmospheric pressure can then be implemented.

[0068] Product program and storage means

[0069] According to a fifth aspect, a computer program product is provided comprising code instructions for executing the method for estimating a value representative of the first pressure and the method for estimating a value representative of the atmospheric pressure, when said program is executed by a computer. According to a sixth aspect, a storage means readable by computer equipment is provided on which a computer program product comprises code instructions for executing the method for estimating a value representative of the first pressure and the method for estimating a value representative of the atmospheric pressure.

[0070] The invention is not limited to the embodiment described and shown in the attached figures. Modifications remain possible, in particular from the point of view of the constitution of the various technical characteristics or by substitution of technical equivalents, without departing from the general teaching.

Claims

DEMANDS 1. Method for estimating a representative value of a first pressure, the first pressure being a fluid pressure in an inflatable element (3) of an implantable medical device (10) comprising a reservoir (5) of fluid with selectively variable volume, the reservoir (5) being capable of deforming under the effect of a variation in atmospheric pressure, the inflatable element (3) in fluidic connection with said reservoir (5), comprising the steps implemented by a control and data processing unit (200) of the device of: a) determining a representative value of a second pressure, the second pressure being a fluid pressure in the reservoir (5),b) estimation of the representative value of the first pressure from the representative value of the second pressure and a parameter (L) depending on a representative value of a maximum fluid pressure variation in the inflatable element (3) caused by a variation in atmospheric pressure.

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

3. Estimation method according to claim 2, wherein the representative value of the first pressure is determined from a representative value of the second reference pressure determined from a representative value of the fluid pressure in the tank (5) measured by the sensor (102).

4. Estimation method according to claim 3, wherein the representative value of the first pressure is determined from a representative value of a first reference pressure, the representative value of the first reference pressure being determined from the representative value of the second reference pressure measured by the sensor (102) and a representative value of reference atmospheric pressure measured by a barometer (90).

5. Estimation method according to claim 4, wherein said barometer (90) is disposed on an external wall of the housing 1 or in the housing 1.

6. Estimation method according to claim 4, wherein said barometer (90) is included in an external control element (9) adapted to exchange data with the implantable medical device and wherein the representative pressure value atmospheric reference is measured following a command implemented by an individual in whom the device is implanted via the external control element (9).

7. Estimation method according to any one of claims 4 to 6, wherein the representative value of first reference pressure is updated at each implementation of a command from an updated representative value of atmospheric reference pressure and a representative value of second reference pressure.

8. Estimation method according to any one of claims 4 to 7, wherein the representative value of first reference pressure is updated at least once a day from an updated representative value of atmospheric reference pressure and representative value of second reference pressure.

9. Estimation method according to any one of claims 3 to 8, wherein the representative value of the second reference pressure is updated at least once a day, preferably at least three times a day, and even more preferably at least five times a day.

10. Estimation method according to any one of claims 1 to 9, wherein the representative value of the second pressure is an average or median of a plurality of representative values ​​of the fluid pressure in the tank (5).

11. Estimation method according to claim 10, wherein the representative value of the second pressure is determined from an average or median of at least three representative values ​​of the fluid pressure in the tank (5).

12. Estimation method according to any one of claims 1 to 11, wherein the representative value of the second pressure is determined from a representative value of a first variation in fluid pressure in the tank (5) caused by a variation in the volume of the tank (5) implemented by an actuator (8) of the device (10).

13. Estimation method according to any one of claims 1 to 12, wherein the representative value of the second pressure is determined from a representative value of a second variation in fluid pressure in the tank (5) caused by a change in the orientation of the device. 14.Estimation method according to any one of claims 1 to 13, wherein the representative value of the first pressure is calculated from the following term:. [Math.1] second_P L second_P being the representative value of the second pressure and L being said parameter dependent on the maximum pressure variation in the inflatable element (3) caused by the variation in atmospheric pressure.

15. Estimation method according to any one of claims 1 to 14, wherein said parameter (L) is obtained beforehand from one or more measurements of a value representative of a third variation of a fluid pressure in the tank (5) caused by one or more variations of atmospheric pressures.

16. Estimation method according to any one of claims 1 to 15, wherein the representative value of the first pressure is determined by calculating: [Ma th.2] second _P_ref L - - - ; - — x first_P_ref second_P L first_P_ref being a representative value of first reference pressure and second_P_ref being a representative value of second reference pressure.

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

18. Implantable medical device (10) comprising a variable volume fluid reservoir (5), an inflatable element (3) in fluidic connection with said reservoir (5) and a control and data processing unit, said unit being configured to implement a method according to any one of claims 1 to 17.

19. Implantable medical device (10) according to claim 18, configured to be implanted in a human or animal body to selectively block an anatomical duct of said human or animal body taken from at least one of the following ducts: a urethra, a gastric duct, a colon and a rectum.

20. An implantable medical device (10) according to claim 19, comprising an elongated inflatable element (3) configured for use as a penile implant.

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

22. Product computer program comprising code instructions for the execution of a process according to any one of claims 1 to 17, when said program is executed by a computer.

23. Computer-readable storage means on which a computer program product includes code instructions for the execution of a process according to any one of claims 1 to 17.

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