MEDICAL DEVICE AND METHOD OF DETECTING A CHANGE OF POSITION

Abstract

A medical device (1) designed to be implanted in the body of a person or animal, which device comprises a housing (2), at least one deformable element (3) and at least one sensor for measuring or calculating pressure, the housing (2) and the deformable element (3) being connected by a tubular connection (5) and implanted in the body of a person or animal at a distance from each other, the medical device (1) being characterised in that it is configured to detect a position and/or a change of position of at least one part of the body depending on a variation in the pressure measured or calculated by the sensor.

Claims

1. A medical device arranged to be implanted in a human or animal body, comprising a casing, at least one deformable element, a tubular connection ensuring a fluid connection between the casing and the deformable element to form a fluidic circuit, and at least one sensor able to measure or calculate a pressure in the fluidic circuit, the casing and the deformable element being adapted to be implanted in the human or animal body distant from each other, wherein the medical device is configured to detect a position and/or a change in position of at least one part of said body as a function of a variation in a pressure measured or calculated by the sensor.

2. The medical device according to claim 1, wherein the casing is rigid and hermetically linked to one end of said tubular connection.

3. The medical device according to claim 1, wherein the deformable element is inflatable.

4. The medical device according to claim 1, wherein the sensor is disposed inside the casing and able to measure or calculate a pressure in the deformable element.

5. The medical device according to claim 4, wherein the casing comprises a fluid reservoir including a movable part and an actuator of the movable part to vary a volume of said reservoir, the sensor able to measure or calculate a pressure being mechanically linked to said movable part and/or to the actuator, in particular in a secured manner.

6. The medical device according to claim 1, wherein the casing and the deformable element are adapted to be implanted in the human or animal body distant from each other along a direction that varies during a change in position of at least one part of said body, in particular during the passage from a standing position to a lying position.

7. The medical device according to claim 6, wherein the casing and the deformable element are adapted to be implanted in the human or animal body distant from each other along a direction substantially equivalent to a longitudinal direction of said body.

8. The medical device according to claim 1, wherein the casing and the deformable element are adapted to be implanted in the human or animal body distant from each other by a distance of at least 5 cm, preferably by a distance of at least 10 cm, more preferably by a distance of at least 20 cm.

9. The medical device according to claim 1, wherein the device comprises a position sensor for at least one part of said human or animal body.

10. The medical device according to claim 1, wherein the device comprises a position sensor for at least one part of the human or animal body, the device being configured to detect the position and/or the change in position of at least one part of said body from a pressure measurement or calculation by the sensor able to measure or calculate the pressure in the fluidic circuit and to confirm said position and/or said change in position from a measurement of the position sensor.

11. The medical device according to claim 1, wherein the device comprises a position sensor for at least one part of the human or animal body, the device being configured to detect the position and/or the change in position of at least one part of said body by the position sensor and to confirm said position and/or said change in position from a measurement or a calculation of the pressure in the fluidic circuit by the sensor able to measure or calculate the pressure.

12. The medical device according to claim 1, wherein the position sensor is chosen among: an accelerometer, in particular an accelerometer arranged to calculate the linear accelerations along three orthogonal axes, a gyroscope and/or an inclinometer.

13. The medical device according to claim 1, wherein the device comprises a control unit configured to perform at least one of the following operations: measuring or calculating a pressure by means of the sensor able to measure or calculate a pressure, detecting a position or a change in position of at least one part of said body as a function of a position sensor for at least one part of said human or animal body and/or of the sensor able to measure or calculate the pressure.

14. The medical device according to claim 13 in combination with claim 5, wherein the control unit is configured to control the actuator to move the movable part of the reservoir and vary the volume of said reservoir.

15. The medical device according to claim 1, wherein the deformable element is an occlusive sleeve arranged to obturate a natural conduit of said human or animal body.

16. The medical device according to claim 1, wherein the device is configured to be implanted in a human or animal body to obturate a natural conduit (4) of said human or animal body comprised among at least: a urethra, a gastric conduit, a colon or a rectum.

17. The medical device according to claim 1, wherein the device is configured to act as a pacemaker or as a nerve stimulator.

18. A method for detecting a position and/or a change in position of at least one part of a human or animal body, wherein said body comprises a medical device comprising a casing, at least one deformable element, a tubular connection ensuring a fluid connection between the casing and the deformable element to form a fluidic circuit, and at least one sensor able to measure or calculate a pressure in the fluidic circuit, the casing and the deformable element being arranged at a distance from each other, in which a position and/or a change in position of at least one part of said body is detected as a function of a variation in the pressure measured or calculated by the sensor able to measure or calculate a pressure.

19. The detection method according to claim 18, wherein the casing and the deformable element are distant from each other along a direction that varies during a change in position of at least one part of said body, in particular during the passage from a standing position to a lying position.

20. The detection method according claim 19, wherein the casing and the deformable element are distant from each other along a direction substantially equivalent to a longitudinal direction of said body.

21. The detection method according to claim 18, wherein the medical device comprises a control unit which performs at least one of the following operations: measuring or calculating a pressure by means of the sensor able to measure or calculate a pressure, detecting a position and/or a change in position of at least one part of said body as a function of a position sensor and/or of the sensor able to measure or calculate the pressure.

22. The detection method according to claim 21, wherein the control unit is configured to control an actuator to move a movable part of a reservoir and to vary the volume of said reservoir.

23. The detection method according to claim 18, wherein a position sensor able to detect a position and/or a change in position of at least one part of the body by means of the sensor able to measure or calculate a pressure, is calibrated.

24. The detection method according to claim 18, wherein the deformable element is inflatable and chosen among an occlusive sleeve arranged to obturate a natural conduit of said human or animal body.

Description

DESCRIPTION OF THE FIGURES

[0048] Other characteristics and advantages of the invention will become apparent from the following detailed description, with reference to the appended drawings in which

[0049] FIG. 1 illustrates a schematic view of a medical device of the artificial sphincter type according to one exemplary embodiment of the invention;

[0050] FIG. 2 illustrates a schematic view of the position of the medical device of FIG. 1 implanted in the human body seen from the front;

[0051] FIG. 3 illustrates a detailed view of the medical device implanted in the body of a man in a standing position seen in profile;

[0052] FIG. 4 illustrates a detailed view of the medical device implanted in the body of a man in the dorsal decubitus position seen in profile;

[0053] FIG. 5 illustrates the detection method according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0054] FIG. 1 schematically illustrates the medical device 1 according to the invention according to one exemplary embodiment in which it corresponds to an artificial urinary sphincter intended to address the incontinence.

[0055] The medical device 1 generally comprises a rigid casing 2 and a deformable element 3. In this example, the deformable element 3 consists of an inflatable occlusive sleeve arranged around at least one part of a natural conduit 4 of the human or animal body, the urethra in this case. The sleeve is preferably made of biocompatible elastomeric material, for example silicone.

[0056] The casing 2 and the occlusive sleeve 3 are linked by a tubular connection 5 and are in fluid connection, that is to say the medical device 1 is arranged to move fluid in variable volume from the casing to the sleeve and vice versa. This is a hydraulically operated device.

[0057] The casing 2 comprises a variable-volume fluid reservoir 6. The reservoir 6, the tubular connection 4 and the occlusive sleeve 3 are all three connected in a fluidic manner so as to form a single and unique fluidic circuit.

[0058] The reservoir 6 comprises a fixed part 7 and a movable part 8. The movable part 8, during its displacement, varies the volume of fluid in the reservoir to transfer it from the reservoir 6 to the occlusive sleeve 3, which then inflates, increasing the pressure to occlude the conduit. Conversely, a displacement of the movable part 8 in the opposite direction causes an increase in the volume of the reservoir, and therefore a transfer of fluid from the sleeve 3 to the reservoir 6. This has the effect of releasing the pressure on the urethra and thus allowing the urination.

[0059] The movable part 8 of the reservoir 6 is mechanically coupled and driven by an actuator 9 to produce a linear displacement relative to the fixed part 7 so as to adjust the volume of the reservoir.

[0060] The actuator 9 can in particular comprise an electromagnetic motor and a reducer. The actuator is controlled by a control unit 10 described in detail below and powered by a rechargeable or non-rechargeable source of energy (not illustrated). In one particular configuration, the energy source is outside the human body and transmits energy wirelessly to the medical device 1.

[0061] The unit 10 is called a control unit but it is understood that it performs simultaneously control functions, monitoring functions and calculation functions, as will appear in the following.

[0062] Furthermore, it is provided according to the invention that the casing 2 also includes a sensor 11 able to measure or calculate the pressure in the fluidic circuit. The sensor 11 measures either directly the exerted pressure or an exerted force and the control unit 10 then calculates the corresponding pressure. In the latter case, the sensor 11 is a force sensor arranged in the casing 2 and for example mechanically linked to the movable part 8 of the reservoir 6 to measure a tensile and/or compressive force in the direction of displacement of the movable part of the reservoir.

[0063] Particularly, the force sensor is adapted to deflect under the application of a compressive or tensile force. This deformation can be measured for example by means of a deformation gauge or strain gauge, and the force applied is determined from the deformation thus measured. Starting from the measured force, the surface of the movable part 8 being known, the control unit 10 can then deduce the corresponding pressure, the force being the product of the pressure by the surface.

[0064] Alternatively, the sensor 11 is mechanically linked to the actuator, itself mechanically coupled with the movable part 8 of the reservoir 6, in particular in a secured manner, so as to measure or calculate the pressure in the fluidic circuit.

[0065] According to the invention, the casing 2 of the medical device 1 can also include a position or posture sensor 13 connected to the control unit 10 to detect the position or the posture and/or the change in position or posture of part of the human or animal body or the whole body.

[0066] This posture sensor 13 is for example in the form of an accelerometer, in particular an accelerometer arranged to calculate the linear accelerations along three orthogonal axes, a gyroscope and/or an inclinometer.

[0067] As illustrated in FIG. 1, the reservoir 6 with its fixed part 7 and its movable part 8, the actuator 9, the control unit 10, the sensor 11 and the sensor 13 are all arranged in the casing 2 of the medical device 1.

[0068] Similarly as shown, the medical device 1 including the casing 2, the sleeve 3 and the tubular connection 5 are implanted in the human or animal body which is symbolized by the line 12 representing the skin of the body in FIG. 1.

[0069] The implanted medical device 1 can be controlled remotely by the patient by means of a wireless control system not implanted in the human or animal body of the remote control type.

[0070] In this case, it is intended for the remote control system to communicate with the medical device via radiofrequency waves or by electromagnetic induction.

[0071] This communication may aim to drive the operation of the implanted device, for example to activate or deactivate it, open or close the occlusive sleeve, configure the internal parameters of the medical device or obtain information from the device, for example know the state of the device or obtain parameters from the patient that are measured by sensors implanted with the device.

[0072] Alternatively, it is also envisaged to be able to monitor the medical device without having recourse to an external control system. In this case, the medical device is equipped with another sensor able to detect a mechanical action exerted on the body, not the patient. This mechanical action can take the form of a tapping of a certain duration and frequency representing a code corresponding to a command.

[0073] FIG. 2 illustrates a human body 12 in a standing position seen from the front with the medical device 1 according to the implanted invention.

[0074] Particularly, it is shown that the casing 2 is implanted in the patient's abdomen while the occlusive sleeve 3 in the case of the artificial sphincter is disposed around the urethra quite below the casing. They are connected by means of the tubular connection 5.

[0075] The casing 2 and the sleeve 3 are therefore implanted at a distance from each other in the human body 12, and particularly at a different height when the patient is standing.

[0076] In what follows, H will refer to the height difference between the casing 2 and the sleeve in the standing position, in other words this corresponds to the distance between the casing 2 and the sleeve 3 according to the vertical direction (direction of gravity) when the patient is in a standing position. According to the invention, the distance H is preferably of at least 10 cm, more preferably by a distance of at least 20 cm.

[0077] This height difference causes a pressure difference between the pressure in the casing 2 and the pressure in the sleeve 3. This hydrostatic phenomenon is called “water column”.

[0078] Particularly, the casing 2 and the sleeve 3 are therefore implanted at a distance from each other along a direction substantially equivalent to a longitudinal direction of said body. This particular positioning induces a change in direction of the axis formed by the casing and the sleeve during a change in posture of the body, in particular during the passage from a standing position to a lying position.

[0079] FIGS. 3 and 4 show respectively the detail of the medical device 1 implanted in the body 12 of a male man seen in profile in the standing position and in the dorsal decubitus position.

[0080] As in FIG. 2, FIG. 3 shows the casing 2 and the sleeve 3 implanted at a distance from each other in the human body 12, with a height difference H when the patient is standing.

[0081] On the other hand, FIG. 4 shows the casing 2 and the sleeve 3 also implanted at a distance from each other in the human body 12, but this time with a height difference h when the patient is in the dorsal decubitus position.

[0082] It is clearly shown that the height difference H in the standing position of the patient is different from the height difference h in the dorsal decubitus position. Furthermore, in the case of the particular implantation of the medical device 1 to address urinary incontinence, the height difference H in the standing position is greater than the height difference h in the dorsal decubitus position.

[0083] Due to the “water column” phenomenon, the pressure measured by the sensor 11 is different in the two positions.

[0084] In the upright position, and as the casing 2 is rigid and is hermetically linked to the end of the tubular connection connected to the reservoir, there is no direct transmission of the pressure due to the “water column” phenomenon, the pressure in the occlusive sleeve 3 is therefore substantially equal to the pressure measured by the sensor 11 in the reservoir 6 plus the pressure corresponding to the water column H above the sleeve 3 and which therefore applies a corresponding pressure.

[0085] In the dorsal decubitus position (cf. FIG. 4), for the same reasons, the pressure in the occlusive sleeve 3 is substantially equal to the pressure measured by the sensor 11 in the reservoir 6 plus the pressure corresponding to the water column h above the sleeve 3.

[0086] In the case of a medical device 1 including a rigid casing 2 and a sleeve 3 of the deformable element type, the pressure in the sleeve 3 is substantially the same in the standing position and in the dorsal decubitus position, while the pressure in the reservoir 6 measured by the sensor 11 is different in the two positions.

[0087] Advantageously, according to the invention, advantage is therefore taken from this effect, specific to the medical device 1, to detect a posture and/or a change in posture of the body by means of the measurement or the calculation of the pressure exerted in the reservoir 6 as will be explained in more detail below.

[0088] It is important to note that the artificial urinary sphincter in three parts (the occlusive sleeve, the regulation balloon and the pump) of the state of the art as described previously does not allow implementing this new function.

[0089] Firstly because it does not comprise a sensor able to measure or calculate the pressure, since it is a passive device, but also because of its different arrangement.

[0090] Indeed, conversely, in this device of the state of the art, the regulation balloon being flexible and deformable, there is a direct transmission of the pressure exerted by the water column to the occlusive sleeve. In this case, it is the pressure exerted by the sleeve that varies according to the position, whereas the pressure in the regulation balloon is the same in the standing position and in the dorsal decubitus position.

[0091] It is therefore not possible, as in the invention, to detect the position or the change in position as a function of the measured pressure.

[0092] With reference to FIG. 5, the posture detection or the posture change method according to the invention will now be described.

[0093] The detection method according to the invention provides for intra-operative steps, implantation steps and post-operative steps.

[0094] The intraoperative step 20 consists in providing the medical device 1 comprising the casing 2, the deformable element 3 and the tubular connection 5, with inside the casing 2, the reservoir 6 equipped with a fixed part 7 and a movable part 8, an actuator 9, a control unit 10, a sensor 11 able to measure or calculate the pressure in the reservoir 6 and the posture sensor 13 as described above.

[0095] In step 21, during the operation, the surgeon implants this medical device 1 in order to obtain the configuration illustrated in FIG. 2 with the casing 2 implanted in the patient's abdomen, the occlusive sleeve 3 distant from the casing 3 and disposed around the urethra 4.

[0096] In step 22, still during the operation, the surgeon connects the casing 2 to the occlusive sleeve 3 by means of the tubular connection 5 to create the fluidic circuit.

[0097] Between steps 21 and 22, a step for purging the device (not detailed here) is also provided so as to discharge the air and fill the device with fluid.

[0098] Once implanted, the medical device can be preferably configured postoperatively.

[0099] The following steps therefore describe the configuration of the medical device 1 to detect a posture and/or a change in posture of the body as a function a variation in the pressure measured or calculated by the sensor 11.

[0100] In step 23, the device 1 is calibrated. For example, this step can consist in asking the patient to take different and known postures such as moving from the standing position to the dorsal decubitus position. During this step, the pressures measured by the sensor 11 are recorded in a table in the memory of the control unit 10 in correspondence with the positions, for example the standing or lying position, or intermediate positions.

[0101] In this correspondence table, it is possible to define thresholds from which it is considered that the patient is in a determined position, for example a lying position or a standing position.

[0102] It will be explained below how these measurements can be combined with the values measured by a posture sensor of the accelerometer type to make the posture detection even more robust and more reliable.

[0103] The calibration step 23 can be performed once or several times over time to refine the measurements and make the detection more robust.

[0104] In step 24 of the detection method, the sensor 11 measures the pressure at regular, preferably frequent, time intervals to be more reactive with regard to the detection of changes in posture or to detect rapid changes in posture. For example, the pressure is measured every 200 milliseconds.

[0105] In step 25, the current pressure value is compared with the previous pressure value and with the values recorded during the calibration step 23 to detect a change in posture and therefore a new posture in step 26.

[0106] According to the invention, the control unit 10 is arranged to repeat steps 24, 25 and 26 at regular and frequent time intervals to detect the posture changes.

[0107] In one particular embodiment of the invention in which the casing 2 of the device includes a posture sensor 13 as described previously, the measured values can be used in addition to the pressure values for the posture detection.

[0108] This posture sensor 13, for example a three-axis accelerometer, also requires calibration in step 23 to allow the accelerometer to be virtually aligned with a known point of reference. A virtual orientation allows matching the 3 axes of the accelerometer with the axes related to the body, that is to say the superior-inferior axis, the posterior-anterior axis and the left-right axis. This virtual orientation is preferably obtained by calculating reference change matrices when the patient takes predetermined postures, the corresponding accelerations are then recorded and the reference change matrix is deduced therefrom, starting from the fact that the only acceleration to which the body is subjected is the gravitational acceleration.

[0109] If the medical device 1 is equipped with such a posture sensor 13, then it is provided in step 24 of the detection method according to the invention, that the posture sensor 13 measures the posture at regular time intervals. As before, it is preferable that the detection of the posture is frequent to be more responsive to changes. For example, the posture is measured every 200 milliseconds.

[0110] Similarly according to this embodiment, in step 25, the value corresponding to the posture is compared. In the example, the current acceleration values are compared with the previous acceleration values and with the values recorded during the calibration step 23 to detect a change in posture and therefore a new posture in step 26. Preferably, in this step, a measurement of the pressure made by the pressure sensor 11, also calibrated in step 23, confirms or invalidates the detection of posture or of change in posture of the posture sensor 13. Finally, in this embodiment, the control unit 10 is also arranged to repeat steps 24, 25 and 26.

[0111] Preferably, in this particular embodiment, it is when a slight variation is detected by the posture sensor 13 on the instantaneous acceleration measurements that a measurement of the pressure is made by the pressure sensor 11 making it possible to infer the current posture. This inference is validated or invalidated by the comparison between the value of the current pressure and the value of the pressure related to the position inferred during the calibration step 23.

[0112] Since the posture sensor 13 is generally more energy-efficient than the pressure sensor 11, this embodiment with an available posture sensor 13 has the advantage of being able to save the overall energy used by the medical device when the pressure sensor 11 is only used to confirm the posture measured by the posture sensor 13 and only in some cases, for example when the variation measured by the posture sensor is low.

[0113] Consequently, the present invention therefore allows a detection of the posture or of the change in posture that is more robust and more reliable in order to allow best adapting the pressure exerted on the natural conduit by the deformable element and thus avoiding overstressing it and damaging it.

[0114] The invention is also applicable to other fields. For example, it is adapted to the medical devices that apply a specific therapy, as in the case of a pacemaker or a nerve stimulator.

[0115] Generally, a pacemaker provides electrical pulses intended to stimulate the heart muscles making it possible to accelerate the pulsation of the heart rate when the latter is too slow.

[0116] In this case, the invention allowing the precise detection of the body posture or of a change in posture, it is possible to detect that a patient is in the lying position because he has just felt faint and that a specific therapy should be applied to modify his heart rate.

[0117] The nerve stimulators are implanted in the human body and connected to the vertebral column. They are further configured to send electrical signals into the epidural space so as to relieve chronic pains.

[0118] The nerve stimulation works by interrupting pain-related signals between the spinal cord and the brain. The brain therefore no longer receives these signals and the patient no longer feels the pain.

[0119] In addition, some pains are often intensified during a change in posture, in particular when the patient lies down, sits down or begins to walk. With the invention, it therefore becomes possible to adapt the different stimulation parameters to these posture variations.

[0120] Unlike the devices for addressing urinary incontinence, in the case of the pacemaker or nerve stimulator, the deformable element is no longer arranged around a natural conduit to be occluded. But in these applications, it takes the form a balloon-type deformable element with no function other than that of being able to reproduce the water column phenomenon. It is therefore still disposed at the end of the tubular connection and always implanted in the body at a distance from the casing at a different height when the patient is standing. As previously described, it is possible to use a different pressure measurement depending on the position and therefore to detect a change in posture. The other elements of the medical device are similar and operate similarly to what has been described previously.

[0121] It is understood that the embodiments described above correspond to specific and non-limiting examples and that various modifications can be made without departing from the invention as claimed.