Device for monitoring a medical prosthesis and the human body

Abstract

A device for monitoring a medical prosthesis and the human body includes a sensor for generating signals depending on surrounding stresses, a processor for processing the signals emitted by the sensor in order to convert the signals into data, a storage device for storing the data, a device for wireless transmission of the stored data, and a supply of electrical energy. The device is included in at least one casing, which is made of biocompatible material and has a device for fixing to a bone.

Claims

1. A device for monitoring a medical prosthesis and the human body, comprising: a sensor, capable of generating signals according to surrounding stresses, a processor, capable of processing the signals transmitted by the sensor to convert them into data, a storage device, capable of storing the data, a wireless transmitter for wirelessly transmitting the stored data, an electrical energy power supply, in which said sensor, processor, storage device, transmitter and power supply are included in at least one housing made of biocompatible material, wherein said at least one housing is a hollow tubular housing, extending in a longitudinal direction (I-I) and is secured reversibly to a substantially tubular sleeve with outer wall provided with an outer threading, said substantially tubular sleeve being intended and designed to be fixed to a bone, wherein: the tubular housing and/or substantially tubular sleeve comprises an end provided with means for driving in rotation about the longitudinal direction (I-I).

2. The device as claimed in claim 1, wherein the sensor is sensitive to electrical, chemical, mechanical or optical stresses.

3. The device as claimed in claim 1, wherein the sensor comprises a gyrometer.

4. The device as claimed in claim 1, wherein the sensor comprises an inclinometer.

5. The device as claimed in claim 4, wherein said inclinometer is of magnetometer type.

6. The device as claimed in claim 1, wherein the sensor comprises an accelerometer.

7. The device as claimed in claim 1, wherein the sensor comprises a pressure sensor.

8. The device as claimed in claim 1, wherein the sensor comprises a sensor for measuring the conductivity of the surrounding medium.

9. The device as claimed in claim 1, wherein the sensor comprises a temperature sensor.

10. The device as claimed in claim 1, wherein the sensor comprises a sensor for measuring the pH.

11. The device as claimed in claim 1, wherein the sensor comprises an optical sensor designed to detect the color of the surrounding medium.

12. The device as claimed in claim 1, wherein the electrical energy power supply comprises a renewable energy source configured to convert accelerations undergone by said at least one housing into electrical energy.

13. The device as claimed in claim 1, further comprising a controller to disable the operation of the sensor and/or processor during predetermined time bands.

14. The device as claimed in claim 1, further comprising a controller to allow the operation of the processor only after the sensor has detected movements for a duration greater than a predetermined duration.

15. The device as claimed in claim 1, further comprising a controller to allow the operation of the processor only after the sensor has detected movements with an amplitude greater than a predetermined amplitude.

16. The device as claimed in claim 1, wherein: the storage device contains predetermined reference data, the device comprises comparison means, designed to compare the data obtained from the processing of the signals transmitted by the sensor with the predetermined reference data, in the event of nonconformity of the data obtained from the processing of the signals transmitted by the sensor with the predetermined reference data, an anomaly signal is generated and stored in the storage device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other objects, features and advantages of the present invention will emerge from the following description of particular embodiments, given in relation to the appended figures, in which:

(2) FIG. 1 is a plan view of a device for monitoring a medical prosthesis and the human body, according to a first embodiment of the invention;

(3) FIGS. 2 and 3 are schematic cross-sectional front views of two variants of the device of FIG. 1;

(4) FIG. 4 is a plan view of a variant of the device of FIG. 1;

(5) FIG. 5 is a perspective view of a device for monitoring a medical prosthesis and the human body that does not form part of the present invention;

(6) FIG. 6 is a schematic cross-sectional side view of a device for monitoring a medical prosthesis and the human body, according to a third embodiment of the invention;

(7) FIG. 7 is a perspective view of the device of FIG. 6;

(8) FIG. 8 is a schematic cross-sectional side view of a variant of the device of FIG. 6;

(9) FIG. 9 is a schematic view illustrating an example of operation of a device for monitoring a medical prosthesis and the human body according to the invention; and

(10) FIGS. 10 and 11 are schematic views illustrating examples of implantation of the device of FIGS. 6 to 8.

DESCRIPTION OF PREFERRED EMBODIMENTS

(11) FIGS. 1 and 6 respectively illustrate two embodiments of the device for monitoring a medical prosthesis and the human body. In each of these figures, a device 1 for monitoring a medical prosthesis and the human body can be distinguished, comprising:

(12) sensor means 2, capable of generating signals according to surrounding stresses,

(13) processing means 3, capable of processing the signals transmitted by the sensor means 2 to convert them into data,

(14) storage means 4, capable of storing the data,

(15) means 5 for wirelessly transmitting the stored data,

(16) electrical energy power supply means 6,

(17) a leak-tight housing 7 made of biocompatible material, in which are included the sensor 2, processing 3, storage 4, transmission 5 and power supply 6 means,

(18) the housing 7 comprising means 8 for fixing to a bone.

(19) Control means (not represented) drive one or more of the sensor means 2, of the processing means 3, of the storage means 4, of the transmission means 5 and of the power supply means 6.

(20) Examples of biocompatible materials from which to make the leak-tight housing 7 are: titanium, titanium alloy, stainless steel, polymer (notably PEEK).

(21) In a variant not represented in the figures, the device 1 comprises at least one first housing, containing the electrical energy power supply means 6, and which is linked to a second housing by electrical conduction means.

(22) In the variant illustrated in FIG. 9, the device 1 comprises:

(23) a first housing 70 and a second housing 700,

(24) at least one of the two housings 70 or 700 comprises sensor means 2 (not visible) designed to detect the relative position of the other housing.

(25) For such sensor means 2, reference can notably be made to the teachings of the document WO 2010/003824.

(26) In order to make use of the stored data, the latter are transmitted to a remote terminal 9 provided with reception means 11. The remote terminal 9 and the reception means 11 are designed to directly receive the data stored in the first housing 70 via the transmission means of the housing 70 and to directly receive the data stored in the second housing 700 via the transmission means of the second housing 700.

(27) It is, however, possible for a direct transmission between the first housing 70 or the second housing 700 and the remote terminal 9 to be subject to a wave propagation defect. For example, fatty tissues may absorb a significant proportion of the waves and thus prevent the transmission of the stored data directly from one of the housings 70 or 700 to the remote terminal 9. In this case, it is advantageous to provide for:

(28) the device 1 to comprise means for communication between the first and second housings 70 and 700, enabling one and/or the other of the housings 70 or 700 to receive data from the other housing 70 or 700,

(29) at least one of the housings 70 or 700 to comprise means for wirelessly transmitting the stored data in order to transmit the data received from the other housing 70 or 700.

(30) The first housing 70 and/or the second housing 700 can thus act as a relay in the transmission of the stored data contained in the other of the housings 70 or 700.

(31) FIG. 2 illustrates a variant of a device of FIG. 1 comprising a shim 12 which comprises:

(32) a first face 12a intended to bear against the bone 13 by means of a shaping adapted to the external shape of the bone 13,

(33) a second face 12b, substantially opposite the first face 12a, intended to bear against a face 7a of the housing 7 by means of a shaping adapted to the face 7a of the housing 7.

(34) The housing 7 thus comes indirectly into intimate contact with the bone 13.

(35) In another variant illustrated in FIG. 3, the housing 7 can itself comprise a face 7a intended to bear against the bone 13 by means of a shaping adapted to the external shape of the bone 13.

(36) The variant of FIG. 2 offers the advantage, compared to the variant of FIG. 3, of having to change only the shim 12 according to the shape of the bone, in order to fix a unique housing 7 of standardized shape.

(37) FIG. 2 shows that the fixing means 8 of the housing 7 comprise:

(38) a single screw 14 for securing the housing 7 to the bone 13,

(39) means for blocking the rotation 15 of the housing 7 relative to the securing screw 14.

(40) For this, provision is made for:

(41) the securing screw 14 to comprise a bottom part 14a with thread 14b with osteo-integration means,

(42) the securing screw 14 to comprise a top part 14c comprising locking means 16 for the housing 7 on the top part 14c.

(43) In practice, it can be seen in FIG. 2 that the top part 14c of the securing screw 14 has a non-circular section to cooperate, by complementarity of shapes, with a recess 17 providing in the housing 7 to receive the top part 14c.

(44) Alternatively, as represented in FIG. 3, the fixing means 8 of the housing 7 may comprise:

(45) a single screw 14 for securing the housing 7 to the bone 13,

(46) means for blocking the rotation 15 of the housing 7 relative to the bone 13.

(47) In FIG. 3, the rotation blocking means 15 consist of the face 7a of the housing 7 bearing against the bone 13. There is therefore no need, in this case, for the top part 14c of the securing screw 14 to cooperate by complementarity of shapes with the recess 17 of the housing 7 intended to receive the top part 14c.

(48) It should be noted that, in the case of FIGS. 2 and 3, the securing screw 14 is permanently fixed into the bone 13 but the housing 7 can freely be removed for a replacement or maintenance operation. The dismantling of the housing 7 is performed by unscrewing the locking means 16 which are reversible and which take the form of a screw screwed into the top part 14c of the securing screw 14. The dismantling of the housing 7 for its replacement or maintenance therefore does not affect the bone mass of the patient which will grow and consolidate without disruption around the securing screw 14.

(49) In a variant illustrated in FIG. 4, the housing 7 is fixed to a bone via fixing means 8 comprising two securing screws 14, the top parts 14c of which do not have any rotation blocking means that block the rotation of the housing relative to the bone. These two securing screws 14 simultaneously make it possible to securely attach the housing 7 to the bone and ensure a constant orientation of the housing 7 relative to the bone on which it is fixed.

(50) Depending on the thickness of the bone mass and the state of this bone mass, it may be possible to make use of screw-fixing means 8. In this case, use is made of a device 1 illustrated in FIG. 5 (which does not form part of the present invention), which comprises a housing 7 in the form of a peanut or a figure 8 and fixed to the bone 13 via a flexible link 18 gripping the bone 13.

(51) The flexible link 18 and the shape of the housing cooperate to ensure a constant orientation of the housing 7 relative to the bone 13. It should be noted that other outer shapes of the housing 7 could be used in cooperation with the flexible link 18 to guarantee a constant orientation of the housing 7 relative to the bone 13.

(52) A third embodiment of the invention is illustrated in FIGS. 6 and 7.

(53) In these figures, it can be seen that:

(54) the housing 7 is a hollow tubular housing extending in a longitudinal direction II, capable of being locked in a substantially tubular sleeve 190 with outer wall 19 provided with an outer threading 20,

(55) the tubular housing comprises an end 21 provided with means for driving in rotation 22 about the longitudinal direction II.

(56) In the case in point, the rotation driving means 22 comprise a hexagonal head that makes it possible to screw the housing 7 into the bone mass of the patient.

(57) It can be seen more particularly in FIG. 8 that the fixing means 8 comprise the substantially tubular sleeve 190 with outer wall 19 provided with an outer threading 20. The housing 7 is fitted into the tubular sleeve 190 by force-fitting and/or by complementarity of shapes (screwing or snap-fitting for example), or by any other suitable reversible locking means, so that the driving in rotation in the longitudinal direction II of the housing 7 via the rotation driving means 22 simultaneously drives in rotation the outer wall 19 so as to penetrate by screwing into a bone mass.

(58) It is thus possible to remove the housing 7 and its content in order to perform a maintenance or replacement operation thereon without having to extract the threaded outer wall 19 which can remain permanently in place in the bone mass of the patient, which will not therefore be degraded by the maintenance or replacement operation.

(59) In the variant illustrated in FIGS. 6 to 8, the device 1 according to the invention takes the outer form of a screw. This screw will be able to be implanted for example in the pelvis of the patient as represented in FIG. 11.

(60) The device 1 of FIGS. 6 to 8 will, however, also be able to fulfill the functions of locking screw as illustrated in FIG. 10 where the threaded housing 7 is screwed into the femur 23 of the patient by passing through an opening 24 provided in a femoral rod 25 of the hip prosthesis. The housing 7 with outer threading thus fulfills a function of axial locking of the femoral rod 25. Such an implantation in the femur 23 is also possible but without ensuring any axial locking of a femoral rod.

(61) In all the embodiments described previously, the sensor means 2 may be sensitive to electrical, chemical, mechanical or optical stresses.

(62) In the case of sensor means 2 that need to perform measurements in the surrounding medium, such as a sensor of conductivity, of temperature, or of pH, it will be possible to make provision for said sensor means 2 to be located in immediate proximity to a wall of the housing 7, said sensor means 2 being in contact with the surrounding medium via a permeable wall portion 26 (FIGS. 1 and 4).

(63) In FIGS. 1, 4, 5, 6 and 8, the device 1 comprises disabling means 10 for selectively disabling the sensor means 2 and/or the processing means 3.

(64) In a first mode of operation, the disabling means are configured to disable the operation of the sensor means 2 and/or of the processing means 3 in predetermined time bands. For example, the disabling means 10 can disable the operation of the sensor means 2 and/or of the processing means 3 during the hours of the night for people generally inactive at night.

(65) As an alternative, or in complement, the disabling means 10 are configured to allow the operation of the processing means 3 only after the sensor means 2 have detected movements for a duration greater than a predetermined duration.

(66) Such a mode of operation makes it possible to effectively limit the quantity of signals transmitted by the sensor means 2 to be processed by the processing means 3. Such a mode of operation also makes it possible to limit the data stored by excluding a significant quantity of movements of short duration which are unlikely to generate a significant wear of the prosthesis. Also, this limiting of data simplifies and makes more reliable a statistical analysis of the data to draw clinical teachings therefrom.

(67) As an alternative, or in complement, the disabling means 10 are configured to allow the operation of the processing means 3 only after the sensor means 2 have detected movements with an amplitude greater than a predetermined amplitude.

(68) The use of the disabling means 10 described previously makes it possible to limit the quantity of data to be processed, to save electrical energy in order to increase the life of the device 1 while making it possible to increase the reliability of the statistical data which will be able to be established on the basis of the data stored then transmitted.

(69) In order to refine the clinical tracking of the patients and better understand any malfunctions of the prosthesis, provision is made for:

(70) the data storage means 4 to contain predetermined reference data,

(71) the device 1 to comprise comparison means, designed to compare the data obtained from the processing of the signals transmitted by the sensor means 2 with the predetermined reference data,

(72) in the event of nonconformity of the data obtained from the processing of the signals transmitted by the sensor means 2 with the predetermined reference data, an anomaly signal to be generated and stored in the storage means 4.

(73) The predetermined reference data will, for example, be able to consist of movement amplitudes, movement angles or even movement execution angular velocities. It will thus be possible to monitor, over time, whether the prosthesis initially provided and implanted is still suited to the lifestyle and the behavior of the patient. It will also be possible to continuously check the conformity of the operation of the prosthesis or of its surrounding medium to detect any deviation relative to a situation that is estimated to be normal corresponding to the predetermined reference data.

(74) It is expressly specified that the different sensor means 2, the electrical energy power supply means, the various energy-saving means, but also the different data processing methods by comparison with reference data form distinct inventions of the fixing and locking means and will be able to be the subject of independent protection.

(75) To produce the sensor means 2 and the processing means 3, reference will be able to be made to the teachings of the documents EP 2 106 747, WO 2010/097422, WO 2010/112469 and WO 2010/112470.

(76) The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained within the scope of the claims below.