Prosthetics liner with sensors

Abstract

A liner system (10) for receiving a residual limb (110) of a patient (100) is disclosed. The liner system (10) comprises a liner (15) adapted to receive the limb (110) of the patient (100) and has a substantially tubular body (20) extending from a distal end (23) of the liner (15) to an open proximal end (26) of the liner (15). A plurality of individual sensors (40) is arranged circumferentially on the liner (15) and extends substantially along the length of the tubular body (20), wherein the plurality of individual sensors (40) is adapted to measure physiological data throughout the liner (15). The liner system (10) further comprises a plurality of layers (17). Ones of the individual sensors (40) are adapted measure the physiological data on an inner surface (35) of the liner (10) and other ones of the plurality of sensors (40) are deposited in different ones of the plurality of layers (17) and can measure data which is collected at interfaces within the layers.

Description

Title of the Invention: Prosthetics liner with sensorsCross-Reference to related applications

[0001] This application claims benefit of and priority to LU Patent Application No. LU501062 filed on 21 December 2021.Field of the Invention

[0002] The invention relates to a liner system, such as one used in a prosthetic element, with a plurality of sensors for gathering data about the liner system as well as an evaluation system for evaluating the sensor data.Background of the Invention

[0003] The fitting and shaping of the socket of an artificial limb (prosthesis) to ensure that the artificial limb is an accurate fit with the residual limb of a patient, i.e., an amputee is a challenging task and one of the most difficult to achieve. The socket serves as an interface between the residual limb and the prosthesis, allowing comfortable weight bearing, movement, and balance. The socket, therefore, must be shaped to be a good fit, with an adequate or desired surface bearing or loading to prevent painful points of contact. Pain and discomfort may occur from pressure, friction, increase in temperature, or any other physical situation caused by an improperly fitted socket or a misaligned prosthesis. The socket needs also to be sufficiently tight so that the socket remains firmly held in place during movement, not falling or rotating during the movement of the prosthesis.

[0004] The prosthesis also needs to be adjustable to consider that the volume of the residual limb changes over time. For example, in the first few months after amputation, the stump of the residual limb will change in shape due to changes in fat and muscle distribution in the residual limb. It is also found that as the patients move, there are changes in physiology of the residual limb due to friction within the socket between the residual limb and the socket as well as temperature and humidity changes in the socket. This can make the wearing of the socket uncomfortable for the patient over time. The liner is an additional component worn by a patient who wears a prosthesis. The liner fits between the residual limb of the patient and the socket. The aim of wearing the liner is to reduce the movement between the residual limb and the socket and enables a sense of stability and comfort for the patient.

[0005] Currently there are no systems known that can measure environment, such as temperature or humidity, of the socket to enable information to be obtained about the socket and it’s fit to the residual limb when the prosthesis is in use. The socket can be created by making a mould of the residual limb, and the socket of the prosthesis is shaped according to the shape of the mould. This shaping process is either done manually or executed by a machine under computer control, or a combination of both. Once this rough shaping is completed, the shape of the socket is then fine-tuned, usually manually, to create a comfortable fit with the stump.

[0006] One method to improve the fit of the socket is disclosed in Adapttech’s US Patent US 10,736,757 which teaches an apparatus for identifying the differences in shape and physical contact characteristics at an interface between the socket and the residual limb. The apparatus comprises a conical laser assembly and a capturing element for scanning the surface of the residual limb to produce a surface map of the residual limb. US Patent ‘757 also teaches the use of a plurality of bio-sensors attachable to the surface of the object at locations which are known relative to a reference point and data collecting means connected to the bio-sensors for collecting contact data from the plurality of the bio-sensors. The contact data is processed, and the bio-sensor data is projected onto the surface map to produce a bio-data profile of the residual object. A display is produced indicating pressure points derived from the biodata for a technician to adapt the fit of the socket.

[0007] US Patent ‘757 also teaches that the bio-sensors can be of different types and include, but not limited to, one or more of pressure sensors, temperature sensor, accelerometers, magnetometers, pedometers, galvanic response sensors, humidity sensors, air flow sensors, electromyography sensors, electrocardiography sensors, oximetry sensors and mechanomyography sensors. However, there is no indication as to how to use the data to improve the fit of the socket of the prosthetic once it is being used by the patient.

[0008] One solution to obtaining more information to improve the fit of the socket is know from US Patent No. 8,784,340 Al which teaches the use of a liner fitted over the residual limb. The liner has a plurality of pressure sensors embedded in the liner which are connected to a data acquisition system.

[0009] US Patent No. US 5,993,400 teaches an apparatus and method for monitoring pressure between the surface of a body part (residual limb) and a contact surface on, for example, a prosthetics socket, a bed, or a wheelchair. This apparatus and method in US ‘400 employ a plurality of pressure sensors disposed in a matrix array between the contact surface and the body part. The sensors produce analog force signals proportional to pressure, and a monitor receives the analog signals and produces output signals, preferably digital, having pressure data corresponding to the pressure at each sensor. A computer processor receives the output signals from the monitor to create a force profile for the sensor array. The sensors may be scanned as a read event in variety of manners, including periodic, continuous, and triggered scanning. This monitoring apparatus and method is used, for example, to fit prosthetics, to monitor bed-ridden and wheelchair-bound patients, to reduce pain and sores caused by uneven distribution of pressure and to monitor pressure between a cast and a person. The sensors may be mounted on a single sheet or on strips for positioning along the body, and monitoring is accomplished by multiplexing and digitizing the analog force signals.

[0010] US patent application US 2012 / 143351 Al describes a prosthetic device including a socket assembly defining a cavity and configured to receive a portion of a residual limb of a user within the cavity. The residual limb of the user is received within an inner liner which may be configured to fit around the residual limb and into outer casing. The prosthetic device further includes a force sensing member configured to detect forces applied to the residual limb at a plurality of locations about the portion of the residual limb and generate signals based on the detected force.

[0011] The force sensing member includes a plurality of force sensors that are distributed over the surface of or within the force sensing member. A controller is configured to receive signals from the force sensing member and control operation of a vacuum system configured to control an amount of vacuum applied to the cavity during use of the prosthetic device by the user based at least in part on the signals received from the force sensing member. The force sensors in US ‘351 are not used to measure physiological data and do not provide information on the interface forces between socket assembly and the residual limb. The force sensing member may also include a plurality of overlapping strips of material that may be arranged such that force sensors are defined by the intersections of the strips. It is not described in US ‘351 that the force sensing sensors are deposited in different layers of theinner liner and are adapted to measure physiological data on an inner surface of the inner liner as well as at interfaces within layers of the inner liner.

[0012] Chinese patent CN 107397614 B describes a lower prosthesis with parameter monitoring function including a funnel-shaped lower prosthesis receiving cavity for receiving the residual limb of the leg and a lower prosthetic foot connected to the lower prosthesis receiving cavity through a connecting assembly. The lower prosthesis receiving cavity is covered with an inner liner which enhances the cushioning and protection of the user's residual limbs, and improves the comfort. A plurality of temperature sensors and humidity sensors are provided on the inner side of the inner liner and a plurality of force sensing devices are provided on the outer side of the inner liner. The force sensing devices include a shear force sensor installed on the outer surface of the inner liner, and a pressure sensor which is fixedly installed on the outer side of the shear force sensor. The inner liner does not comprise a plurality of layers and the temperature sensors and humidity sensors are not deposited in different layers of the inner liner.

[0013] US patent application US 2018 / 042509 Al describes a conductive human interface with a fabric layer with an interior surface and an exterior surface. The conductive human interface can include a prosthetic liner. A soft coating overlies the interior surface of the fabric layer. An electrode (to receive EMG signals produced by muscles of the user) or sensor is included to connect with a residual limb. A conductive path connects the electrode or sensor with an electrical connector which, in turn, connects with a prosthetic or other assistive device. The conductive path includes a conductor, such as conductive thread, fabric or ink, having a section overlying the interior surface of the fabric layer. The conductive human interface can further include one or more sensors configured to detect physical characteristics of the conductive human interface, the skin of the user, or both. The one or more sensors can be electrically connected to the conductive path in a manner similar to the electrical connection of the electrodes. At least a portion of the one or more sensors can be embedded within the soft coating. The electrode and the sensors are not described to be deposited in different ones of the fabric layer and soft coating and the electrode or the sensors are not described to be deposited in a different layer than the soft coating.

[0014] US patent application US 2018 / 098865 Al describes an apparatus for achieving a best possible prosthetic fit in a prosthesis system for an amputee. The apparatus includes a sensor array embedded in a gel like substance slipped over a residual limb in a socket configurationwith respect to a prosthesis system. The sensor array can be composed of a plurality of sensors.

[0015] German patent DE 10 2018 125144 B3 describes a body in the form of a prosthesis liner for at least partially covering a contour of a limb. The body has a base body, and at least one sensor that is configured to record measurement data which can be used to determine a distance and / or relative position between two points in or on the base body. The sensors can be Bragg sensors which are incorporated into optical fibers.Summary of the Invention

[0016] A liner system for receiving a residual limb of a patient is disclosed. The liner system comprises a liner adapted to receive the limb of the patient. The liner system comprises a substantially tubular body extending from a distal end of the liner to an open proximal end of the liner. A plurality of individual sensors is arranged circumferentially on the liner and extend substantially along the length of the tubular body. The plurality of individual sensors is adapted to measure physiological data throughout the liner. First ones of the plurality of individual sensors are adapted to measure the physiological data on an inner surface of the liner. The liner system comprises a plurality of layers and second ones of the plurality of sensors are deposited in different ones of the plurality of layers and can measure data which is collected at different interfaces within the layers.

[0017] Further ones of the plurality of individual sensors are adapted to measure the physiological data on an outer surface of the liner. The plurality of individual sensors is linearly connected along the length of the liner. A data collection line is passed through the distal end of the liner and is connected to ones of the plurality of individual sensors.

[0018] The plurality of sensors is selected from the group of sensors comprising oxygen sensors, pressure sensors, temperature sensors, blood-pressure sensors, humidity sensors, glucose sensors, accelerometers, magnetometers, gyroscope, body fat measurement sensors, activity sensors, shear sensor, displacement sensors and force sensors.

[0019] In one aspect, the liner system further comprises a transmitter disposed at the liner system for receiving and transmitting the sensor data from the plurality of sensors.

[0020] A system for evaluating wearing of the liner system is also disclosed. The system comprises a processor for evaluating the sensor data and a receiver for receiving the sensor data from the liner system. The system may also include an evaluation system with a trained model for processing the sensor data and producing results based thereon.

[0021] This document also discloses a prosthetics element comprising the liner system, a socket adapted to fit a residual limb, and an actuator adapted to change the fit of the socket.Description of the Figures

[0022] Fig. 1 shows a liner system.

[0023] Fig. 2 shows the liner system and a socket about a residual limb with an evaluation system.

[0024] Fig. 3 shows the method.Detailed Description of the Invention

[0025] Fig. 1 shows an example of a liner system 10 for placing about a residual limb 110, such as an upper part of the leg, between the residual limb 110 and a socket 120 to which a prosthesis or artificial body part, such as a leg, is attached (see Fig. 2). The liner system 10 has a liner 15 adapted to receive the residual limb 110. The liner 15 has a substantially tubular body 20 with an open proximal end 26 which can be placed over the residual limb and a distal end 23. In the example of Fig. 1, the distal end 23 is shown as being closed, but this is not limiting of the invention. As can be seen in Fig. 1, a plurality of individual sensors 40 are arranged circumferentially around the liner 15 and extend substantially along the length of the tubular body 20 of the liner 15.

[0026] The sensors 40 can be one or more of the group of sensors 40 comprising oxygen sensors, pressure sensors, temperature sensors, blood-pressure sensors, humidity sensors, glucose sensors, accelerometers, magnetometers, gyroscope, body fat measurement sensors, activity sensors, shear sensor, displacement sensors and force sensors. The sensors 40 collectively measure physiological data and other data (collectively called “sensor data” 45) at the interface of the residual limb 110 and the socket 120 as well as in the liner 15 itself. The sensors 40 can also measure data which is collected at interfaces within the layers of the liner itself.

[0027] The purpose of the measurements is to enable prosthetic components, such as the socket 120, to be fitted and adjusted to the residual limb 110 to make the socket 120 and / or the other prosthetic components more comfortable for the patient 100. In one aspect of the socket 120, an actuator 130 can be incorporated to change the fitting of the socket 120.

[0028] One of the most common measurement is the pressure between the socket 120 and the residual limb 110 to avoid the development of sores or bruises on the residual limb 110. Similarly, a measurement of humidity and temperature within the socket 120 and anunderstanding of the distribution of temperature and humidity throughout the socket 120 can improve the comfort of the prostheses for the patient 100. It is also possible to conceive of a socket 120 that can be dynamically adjusted considering the measurements.

[0029] The sensors 40 can be located on an outer surface 30 of the liner 15, as is shown in the inset of Fig. 1. In this case, the sensors 40 will be able to measure the pressure, displacement, and shear forces between the liner 10, the residual limb 110 and the socket 120. This can indicate issues with incorrect fitting of the prosthetic. The sensor 40 can also be located on an inner surface of the liner 15. In this latter case, the sensors 40 are suitable to monitor the physiological data or sensor data 45 of the patient 100 and the residual limb 110, including blood glucose levels, body fat, humidity, and temperature of the residual limb 110.

[0030] It is possible to place different ones of the sensors 40 on different ones of a plurality of layers 17 within the liner system 10, as can be seen on the inset of Fig. 1. The sensors 40 can be pressure sensors. Some of the sensors are placed on an outer one of the plurality of layers 17 and other ones of the sensors are placed on an inner one of the plurality of layers 17. Placing the sensors 40 in the different ones of the plurality of layers 17 enables, for example, to determine if the liner disperses the pressure by comparing the pressure at the interface between the socket 120 and the liner 10 and the pressure between the liner 10 and the residual limb 110.

[0031] The sensors 40 can alternatively be humidity sensors and can be placed at the inner one of the plurality of layers 17 to enable the prediction of formation of blisters.

[0032] The sensors 40 can alternatively be shear stress sensors and can be placed at the outer one of the plurality of layers 17 to enable the prediction of pistoning and rotation of the socket 120.

[0033] The plurality of individual sensors 40 are connected linearly by a data line 42 which emerges from the distal end 23. It will be appreciated that this is only one aspect of the liner system 10 and that other arrangements of the data line 42 are possible. The sensors 40 which are placed on different ones of the plurality of layers 10 of the liner system 10 can alternatively or additionally be connected with the data line 42 extending between the plurality of layers 10 in a radial direction of the liner system 10.

[0034] The data collection line 42 can be connected to a local data processing system 50 which includes a storage 65 for storing the collected sensor data 45 and a processor 70 which is adapted to process locally some of the sensor data 45. The storage 65 can alternatively be included in any other component such as the socket 120. A transmitter 60 can be also connected to the local data processing system 50 for transmitting the sensor data 45 to a dataprocessing system 200 (also termed external device 200), such as but not limited to a smartphone or other mobile device. The sensor data 45 can alternatively be transmitted wirelessly by the transmitter 60.

[0035] The processor 70 and / or the storage 65 and / or the transmitter 60 of the local data processing system 50 can alternatively be placed within the socket 120. The processor 70 and / or the storage 65 and / or the transmitter 60 can, for example, be placed at ones of the plurality of layers 17 of the liner 10 near the distal end 23. The quantity of data that needs to be transmitted via the data collection line 42 to the local data processing system 50 can be reduced by placing the processor 70 and / or the storage 65 and / or the transmitter 60 inside of the socket 120. If the processor 70, the storage 65 and the transmitter 60 are placed withing the socket 120 the data line 42 is not required to emerge from the distal end 23.

[0036] The local data processing system 50 pre-processes the sensor data 50 before transmission. The external device 200 can present a visual display of the sensor data 45 to the user and can upload to the sensor data 45 and / or the processed sensor data from the local data processing system 50 to a data evaluation system 210 for processing the sensor data 45. The data evaluation system 210 is, for example, located in the cloud. Results of the data evaluation system 210 can be transmitted back to the socket 120 through a transmitter and used by the actuator 130 to make an adjustment of the socket 120 and thus the fit of the prosthetic device to the residual limb 110.

[0037] As shown in Fig. 2, the data processing system 200 receives the sensor data 45 from the transmitter 60 through a receiver 150 and passes the sensor data 45 to an evaluation system 210 for processing. In one aspect, the evaluation system could include a trained model which is able to interpret the sensor data 45 and provide predications based on past issues. For example, the sensor data 45 could indicate that the residual limb 110 was becoming damaged due to overuse of the prosthesis and indicate to the patient 100 that they should rest. Alternatively, the evaluation system 210 could indicate to adjusters in the socket 120 that an adjustment should be made to the socket to avoid damage to the socket 120 of the residual limb 110.

[0038] The trained model is developed from collecting the sensor data 45 from patients over a period of time together with observations from the patients themselves, their clinicians, and fitting technicians. The trained model can be programmed to warn of potential problems at an early stage since the trained model can flag up abnormalities in the fit of the prosthetic device. For example, the sensor data 45 might indicate that sores or bruises are about to develop on the residual limb 110 because of the increase of humidity and / or temperature in the socket.

[0039] The trained model can also be used to adjust the fit of the socket. The sensor data 45 might indicate that there is movement between the socket 120 and the residual limb 110 under certain conditions, such as fast walking or running. The trained model will indicate that the socket 120 may need to be tightened, for example by use of the actuator 130 to overcome such issues.

[0040] A non-limiting example of the data processing is shown in Fig. 3 in which in step 410 the sensor data 45 is acquired from the sensors, pre-processed and recorded in step 420 in the local processing system 50. The sensor data 45 can be transmitted in step 430 through the transmitter 60 to the evaluation system 210 which could be part of the cloud and / or the data processing system 200 (such as an external device). A presentation of the sensor data 45 and the functioning of the prosthesis is generated in step 440. The functioning of the prosthesis can be represented by means of parameters, such as pressure between the socket 120 and the residual limb 110, humidity and temperature within the socket 120 and the distribution of temperature and humidity throughout the socket 120. The functioning of the prosthesis could also be represented by a separate parameter that is calculated as a composite parameter and depends on measured parameters such as pressure between the socket 120 and the residual limb 110, humidity and temperature within the socket 120 and the distribution of temperature and humidity throughout the socket 120. The sensor data 45 is further processed in the evaluation system 210 in step 450 and the processed data is presented in step 460. In a further, optional step 470, the processed sensor data in step 450 is used to adjust the socket 120 using the actuator 130.

[0041] The purpose of the measurements is to enable the socket 120 to be fitted and adjusted to make the socket 120 and the prostheses more comfortable for the patient 100. One of the most common measurements is the pressure between the socket 120 and the residual limb 110 to avoid sores or bruises to develop on the residual limb 110. Similarly, a measurement of humidity and temperature within the socket 120 and an understanding of the distribution of temperature and humidity throughout the socket 120 can improve the comfort of the prostheses for the patient 100.Reference Numerals10 Liner System15 Liner17 Layers20 Tubular Body23 Distal end26 Proximal end30 Outer surface35 Inner Surface40 Sensors42 Data line45 Sensor data50 Local processing system60 Transmitter65 Storage70 Microprocessor100 Patient110 Limb120 Socket130 Actuator150 Receiver200 Data processing system210 Evaluati on sy stem

Claims

Claims A liner system (10) for receiving a residual limb (110) of a patient (100), the liner system (10) comprising:- a liner (15) adapted to receive the limb (110) of the patient (100) and comprising a substantially tubular body (20) extending from a distal end (23) of the liner (15) to an open proximal end (26) of the liner (15);- a plurality of individual sensors (40) arranged circumferentially on the liner (15) and extending substantially along the length of the tubular body (20), wherein the plurality of individual sensors (40) are adapted to measure physiological data throughout the liner (15); and- a plurality of layers (17), wherein first ones of the plurality of individual sensors (40) are adapted to measure the physiological data on an inner surface (35) of the liner (10); and second ones of the plurality of individual sensors (40) are deposited in different ones of the plurality of layers (17) and are adapted to measure data which is collected at interfaces within the plurality of layers (17). The liner system (10) according to claim 1, wherein further ones of the plurality of individual sensors (40) are adapted measure the physiological data on an outer surface (30) of the liner (10). The liner system (10) according to any of the above claims, wherein the plurality of individual sensors (40) is linearly connected along the length of the liner (15). The liner system (10) according to any of the above claims, wherein a data line (42) is passed through the distal end (23) of the liner (10) and is connected to ones of the plurality of individual sensors (40). The liner system (10) according to any of the above claims, wherein ones of the plurality of sensors are selected from the group of sensors comprising oxygen sensors, pressure sensors, temperature sensors, blood-pressure sensors, humidity sensors, glucose sensors, accelerometers, magnetometers, gyroscope, body fat measurement sensors, activity sensors, shear sensor, displacement sensors and force sensors.The liner system (10) according to any of the above claims, further comprising a storage 65 for storing the sensor data (45) and a transmitter (60) disposed at the liner system (10) for receiving and transmitting the sensor data (45) from the plurality of sensors (40). A system (200) for evaluating wearing of the liner system (10) according to one of claims 1 to 6, further comprising a processor (70) for evaluating the sensor data (45). The system (200) of claim 7, further comprising a receiver (150) for receiving the sensor data (40) from the liner system (10). The system (200) of claim 7 or 8, further comprising an evaluation system (210) for processing the sensor data (45) and producing results based thereon. Use of the liner system of one of claims 1 to 6 in a prosthetics element. The use of claim 10, further comprising adjusting the fit of the prosthetics element. A prosthetics element (120) comprising the liner system (10) of one of claim 1 to 6, a socket (120) adapted to fit a residual limb (110), and an actuator (130) adapted to change the fit of the socket (120).

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