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EP-4739196-A1 - SENSOR DEVICE FOR MEASURING MECHANO-BIOLOGICAL PARAMETERS AND DEVICES INCLUDING SUCH A SENSOR

EP4739196A1EP 4739196 A1EP4739196 A1EP 4739196A1EP-4739196-A1

Abstract

Sensor device (12) for detection and preferably also measurement of a force and/or displacement acting in three space directions on at least one activation member (3) of the sensor device (12), wherein the sensor device (12) comprises at least one elastically deformable membrane (2), and at least one sensing element (4), wherein said at least one sensing element (4) is suitable and adapted to detect and measure one or both of a tension and compression of an elastically deformable material of the elastically deformable membrane (2) on and/or in which the at least one sensing element (4) is located, wherein said at least one elastically deformable membrane (2) is, on an outer portion thereof (26), attached to and/or integral with a framing (2), wherein said at least one elastically deformable membrane (2) comprises a central portion (27) distanced from said outer portion (26), and a surrounding portion (29) circumferentially surrounding said central portion (27), wherein said at least one activation member (3) is attached to and/or integral with said central portion (27), and wherein said at least one sensing element (4) is at least partially provided on and/or integrated with and/or coupled with said surrounding portion (29) of said at least one elastically deformable membrane (2).

Inventors

  • WINDOLF, MARKUS

Assignees

  • Bios Medical AG

Dates

Publication Date
20260513
Application Date
20240617

Claims (15)

  1. 1 . Sensor device (12) for detection and preferably also measurement of a force and/or displacement acting in three space directions on at least one activation member (3) of the sensor device (12), wherein the sensor device (12) comprises at least one elastically deformable membrane (2), and at least one sensing element (4), wherein said at least one sensing element (4) is suitable and adapted to detect and measure tension or compression of an elastically deformable material of the elastically deformable membrane (2) on and/or in which the at least one sensing element (4) is located, wherein said at least one elastically deformable membrane (2) is, on an outer portion thereof (26), attached to and/or integral with a framing (28), wherein said at least one elastically deformable membrane (2) comprises a central portion (27) distanced from said outer portion (26), and a surrounding portion (29) circumferentially surrounding said central portion (27), wherein said at least one activation member (3) is attached to and/or integral with said central portion (27), and wherein said at least one sensing element (4) is at least partially provided on and/or integrated with and/or coupled with said surrounding portion (29) of said at least one elastically deformable membrane (2).
  2. 2. Sensor device (12) according to claim 1 , wherein said activation member (3) protrudes from a first surface (2") of said elastically deformable membrane (2), and wherein the at least one sensing element (4) is located on said first surface (2") or an opposite second surface (2'), wherein preferably the at least one sensing element (4) is located on said second surface (2'), wherein preferably said activation member (3) takes the form of a pin or a rod, preferably with circular cylindrical cross-section, of constant or variable diameter, preferably with an engagement feature (13) at its tip configured to transmit deformation or loading of a measurement object to the activation member (3).
  3. 3. Sensor device (12) according to any of the preceding claims, wherein the activation member (3) is separate and attached, preferably at least one of press-fit or screwed or welded, to a central portion of the elastically deformable membrane (2), or is integral with the elastically deformable membrane (2), and is preferably made of the same material as the elastically deformable membrane (2), wherein the thickness of the elastically deformable membrane (2) is smaller than the minimum dimension of the activation member (3) in a direction parallel to the plane of the elastically deformable membrane (2), preferably by at least a factor of 2 or a factor of 4 smaller.
  4. 4. Sensor device (12) according to any of the preceding claims, wherein there are at least 2 sensing elements (4), preferably at least 3 sensing elements (4), or at least 4 sensing elements (4), most preferably in the range of 2-10 or 2-6 sensing elements (4), at least partially attached to and/or integral with said surrounding portion (29), wherein preferably the sensing elements (4) are distributed, preferably regularly, around a circumference of the surrounding portion (29), preferably at least group-wise with equal radial distance from the central portion (27).
  5. 5. Sensor device (12) according to the preceding claim, wherein there are provided at least 2 or at least 4 sensing elements (4) which are located adjacent to or at least partially in a transition region between the central portion (27) and the surrounding portion (29), and/or wherein there are provided at least 2 or at least 4 sensing elements (4) which are located adjacent to or at least partially in a transition region between the surrounding portion (29) and the framing (28).
  6. 6. Sensor device according to any of the preceding claims, wherein the framing (28) is part of a housing (1) enclosing an interior cavity (1 '), which is preferably hermetically sealed, opposite to a protrusion direction of the activation member (3) and having a housing wall (1") with a housing wall thickness, and wherein the housing wall (1") forms the framing (28), wherein preferably the housing (1), at least in the region of the framing (28), is integral with and preferably consists of the same material as the elastically deformable membrane (2) and preferably of the same material as the activation member (3).
  7. 7. Sensor device (12) according to any of the preceding claims, wherein the elastically deformable membrane (2) is a contiguous membrane, preferably with essentially the same thickness over its whole surface extension, and/or wherein the elastically deformable membrane (2) has a polygonal, preferably regularly polygonal shape, or has a rounded shape, preferably an oval and most preferably a circular shape, and/or wherein the framing (28) is part of the housing (1), which in a plane parallel to the plane of the elastically deformable membrane (2) has the same shape of outer and/or inner circumference as the elastically deformable membrane (2), wherein preferably the housing (1) is circular cylindrical, and/or wherein the framing (28) has the same shape of inner circumference as the elastically deformable membrane.
  8. 8. Sensor device (12) according to any of the preceding claims, wherein at least 2 sensing elements (4) are configured in at least one Wheatstone half bridge, and/or wherein at least one sensing element (4) is configured in in at least one Wheatstone quarter bridge, and/or wherein at least four sensing elements (4) are configured in in at least one a Wheatstone full bridge, and/or wherein four sensing elements (4) are configured in two independent (Wheatstone) half bridges to pick up two independent strain signals in orthogonal directions.
  9. 9. Sensor device (12) according to any of the preceding claims, wherein the at least one sensing element (4) is a resistive foil strain gauge, a capacitive, piezo-based or photoelectric strain gauge, or a combination thereof, and/or wherein the at least one sensing element (4) is attached to and/or integrated into the membrane by a thin film sputtering process.
  10. 10. Sensor device (12) according to any of the preceding claims, wherein the activation member (3) comprises an engagement feature (13), which is preferably configured as at least one through-hole for receiving one of the following, a medical suture, fiber, strap band, cerclage-wire or -cable and/or wherein preferably the activation member is directly or indirectly coupled to a medical suture, fiber, strap band, cerclage-wire or -cable, and wherein further preferably said sensor device (12) is configured to measure wire/suture tension either by means of activation member bending, or activation member tension/compression.
  11. 11. Sensor device (12) according to any of the preceding claims, wherein the sensor device (12) is integrated and/or attached to and/or housed in a device to be worn by and/or connected to a device implanted in a human being or animal and/or implanted in a human being or animal, preferably in a device selected from the group of medical devices, preferably selected from the group of bone screws, in particular a screw or blade component of a cephalic nailing implant or a sliding hip screw and/or blade or an angular stable locking screw or a compression lag screw or an interlocking bolt or a pedicle screw, or an intramedullary nail, a bone plate, a hip-, knee- or shoulder endoprosthesis, a rod of a spinal pedicle screw system or a rod or Schanz pin of an external fixator system.
  12. 12. Sensor device (12) according to any of the preceding claims, wherein the elastically deformable membrane (2) is part of or attached to the housing (1), which is attached to or integrated into a device or itself comprises attachment means (7) for attaching the device to a reference object, wherein preferably the attachment means (7) is configured as at least one of an external or internal thread, as at least one through hole or open or closed eyelet, or as a press-fit member with conical or cylindrical shape, or as a releasable clamp or as a glued connection. and/or wherein the housing (1) comprises a drive feature for engagement with a tool, in particular a screwdriver, and/or wherein the housing (1) is designed as a bone screw or an intramedullary nail.
  13. 13. Sensor device (12) according to any of the preceding claims, wherein the device comprises a housing (1) and wherein the housing incorporates an electronic unit (9) with at least one signal conditioner connected to the at least one strain gauge, an analog digital converter, a data processor and a memory to store at least the recorded strain data, where preferably the electronic unit (9) additionally comprises a wireless data transfer unit connected to the memory and to an antenna (5), and wherein further preferably the wireless data transfer unit is based on a wireless communication standard such as Bluetooth, preferably Bluetooth Low Energy, Zigbee or an RFID (radiofrequency identification) based standard, preferably NFC (near field communication) and/or wherein the electronic unit comprises additional sensors connected to the data processor measuring one or a combination of the following dimensions: acceleration of the housing (Accelerometer), angular speed (Gyroscope), location and position (GPS, global positioning system), ambient temperature and/or wherein the housing incorporates a battery (6) configured to supply the at least one strain gauge and the electronic unit with energy, and/or wherein the housing incorporates an energy harvesting device and/or wherein the housing incorporates an RF induction coil
  14. 14. Use of the sensor device (12) according to any of the preceding claims to intermittently of continuously monitor the loading or deflection of a bone screw, implanted into a bone, in particular used as a component of a cephalic hip nail after proximal femur fracture fixation, inserted into a locking hole of an intramedullary nail, attached to a bone plate in an angular stable or non- angular stable manner, or to monitor the suture, cerclage or strap tension when slinged around body tissues, or to monitor the suture tension during and after a tendon or ligamental repair procedure, or to monitor loading or deflection of an implanted intramedullary nail, or to intra-operatively measure the deflection of an intramedullary nail during insertion into a bone to guide positioning of the interlocking bolts, or to monitor the loading or deflection of the rods of a spinal posterior instrumentation after spinal stabilization or deformity correction surgery, or to monitor the loading or deflection of the rods or Schanz pins of an external fixator, or to monitor micromotion and/or migration of a knee-, hip- or shoulder endoprosthesis, or to monitor the loading of a foot inside a shoe or boot.
  15. 15. Device with a sensor device (12) according to any of the preceding claims 1- 13, to be worn by and/or connected to a device implanted in a human being or animal and/or implanted in a human being or animal, preferably device selected from the group of medical devices, preferably selected from the group of bone screws, in particular a screw or blade component of a cephalic nailing implant or a sliding hip screw and/or blade or an angular stable locking screw or a compression lag screw or an interlocking bolt or a (spinal) pedicle screw, or an intramedullary nail, a bone plate, a hip-, knee- or shoulder endoprosthesis, a (connecting) rod of a spinal pedicle screw system or a rod or Schanz pin of an external fixator system.

Description

TITLE SENSOR DEVICE FOR MEASURING MECHANO-BIOLOGICAL PARAMETERS AND DEVICES INCLUDING SUCH A SENSOR TECHNICAL FIELD The present invention relates to a sensor arrangement for measuring mechano-biological parameters e.g. on implants, medical devices or biological tissues including but not limited to ligaments, tendons, bones, muscles and blood vessels, internally or externally to the human body, to devices including such sensor arrangements, methods of using such sensor arrangements and methods of manufacturing such sensor arrangements. PRIOR ART US 2016/0128573 A1 discloses systems, methods, and an apparatus for obtaining medical diagnostic measurements from implanted sensors. In various embodiments, a spinal implant-monitoring apparatus may include: a bridge defining a first hermetically-sealed interior and two or more legs; one or more strain gauges contained within the first hermetically-sealed interior of the bridge to provide a signal indicative of strain measured between the legs of the bridge; a housing defining a second hermetically-sealed interior, the housing mounted on a surface of the bridge; and control circuitry contained within the second hermetically-sealed interior. The control circuitry may be in communication with the one or more strain gauges and may be configured to convert the signal into digital data representative of the signal. Methods of using such apparatus are also disclosed. Drawbacks of this apparatus are its complexity and space requirements making it unsuitable to measure in confined spaces like implant cannulations remote to the point of strain pickup (strain gauges location). Another drawback is the anisotropic deflection behavior of the proposed structure under different loading directions making the apparatus unsuitable to measure a multitude of loading dimensions in different planes under bending, torsion or tension/compression. Yet another drawback of the proposed apparatus is the presence of two separated and sealed compartments, rendering signal and energy transmission through hermetic barriers necessary, which is technically demanding. US-A-2018242864 discloses systems and methods for monitoring physiological parameters such as intracranial pressure (“ICP”), intracranial temperature, and subject head position. In some embodiments, an implantable apparatus for measuring ICP can be implanted into a subject skull. The apparatus can comprise an implant body having a hermetically sealed chamber housing a gas at a reference pressure, and a pressure conduction catheter having a proximal end and a distal end, wherein the distal end is configured to extend into the brain through a burr hole in the skull and includes a plurality of ports. A barrier can cover the ports of the distal end of the pressure conduction catheter, wherein the barrier and pressure conduction catheter are filled with a number of gas molecules so that the barrier is not in tension in a predefined range of ICPs. The ports may also be configured such that a barrier is not necessary. Standoffs on the body may be included that stabilize the implant on the skull and enhance reliability and robustness of the measurements. WO-A-2023018693 concerns an implantable sensor. The implantable sensor includes a sensor assembly configured to connect to a suture. The sensor assembly also includes a substrate and a resonant circuit coupled to the substrate. The resonant circuit is configured to electrically resonate at a resonant frequency when exposed to a first electromagnetic field and to emit a second remotely detectable electromagnetic field. The substrate is configured to deform in response to a tensile force applied by the suture and to change a resonant parameter of the resonant circuit in response to the deformation. SUMMARY OF THE INVENTION An object of the invention is to provide a sensor device in particular for measuring mechano- biological parameters on implants, medical devices or biological tissues including but not limited to ligaments, tendons, bones, muscles and blood vessels, internally or externally mounted to the human body. Body generated forces act on these structures and cause elastic and plastic deformations and deflections of the structures, which are desired to be monitored to diagnose and inform treatment of pathologic conditions and illnesses. In the non-pathologic case, such information can be valuable for health state monitoring and prediction of illnesses and injuries. Particularly when it is intended to surgically implant a sensor device, such data can be highly informative due to direct measurement at the region of interest as opposed to external measurements. However, space constraints play an increasing role in the implanted case. For example, when it is desired to measure deflection or loading of a hip screw, an intramedullary nail or a bone screw, there is the problem of measuring on small implant surfaces or in narrow cannulations which have typically a diameter in the range of 1-5