In-vivo service sport and stress state personalized self-monitoring intelligent bionic intervertebral discTechnical Field
The invention relates to the technical field of medical prostheses, in particular to an intelligent bionic intervertebral disc with personalized self-monitoring of in-vivo service sports and stress states.
Background
Intervertebral disc degenerative diseases, which are a serious threat to spinal health, are widely present worldwide, severely affecting the quality of life of patients. For this chronic condition, artificial disc replacement is a promising therapeutic approach because of its ability to effectively restore spinal stability and reduce pain in patients. However, despite certain success, current prosthetic disc designs still have certain limitations.
Specifically, the traditional artificial intervertebral disc depends on a mechanical joint and a single material, so that complex motion characteristics of the biological intervertebral disc are difficult to accurately reproduce, natural motion modes of the artificial intervertebral disc and the spine are difficult to be completely matched after implantation, and complications such as loosening, sinking or shifting of a prosthesis can be induced. To overcome the limitations described above, a bionic disc has been developed. The bionic intervertebral disc improves the compatibility and the motion matching performance with the spine by simulating the anatomical structure and biomechanical characteristics of the bionic intervertebral disc, and reduces the risk of complications.
Despite advances in design and function of the bionic disc, a key problem is still faced, namely the lack of autonomous dynamic intelligent monitoring capability and feedback mechanism. Currently, the postoperative rehabilitation review of patients is highly dependent on medical image examination (such as X-ray and CT) with high cost, and the means require frequent medical treatment of patients, so that the risk of excessive X-ray radiation exists, and the static evaluation at a specific time point is limited, so that the continuous, dynamic and personalized monitoring of the motion and stress state of the bionic intervertebral disc in the patient can not be realized. The invention patent application with the application number 202410575100.0 discloses a mechanical anisotropic bionic intervertebral disc, which is only improved in terms of the mechanical structure of the bionic intervertebral disc and has no autonomous dynamic intelligent monitoring capability and feedback mechanism.
In view of the foregoing, there is a need to develop an intelligent bionic intervertebral disc with real-time continuous monitoring function (including direction, angle and external load changes), which has important scientific significance and clinical use value for personalized intelligent rehabilitation of total disc replacement patients. In addition, abnormal intervertebral movement and stress in the postoperative rehabilitation process are timely early-warned through monitoring intervertebral stress and strain, so that personalized intelligent monitoring and rehabilitation promotion of the patient are realized.
Disclosure of Invention
The invention aims to solve the problem that the existing bionic intervertebral disc lacks autonomous dynamic intelligent monitoring capability and feedback mechanism, and provides an intelligent bionic intervertebral disc with personalized self-monitoring in-vivo service motion and stress state.
An intelligent bionic intervertebral disc with personalized self-monitoring in-vivo service movement and stress state comprises an upper endplate, an intervertebral disc core and a lower endplate;
the upper end plate is provided with upper end plate fixing teeth;
The nucleus pulposus is used as a peripheral structure of the nucleus pulposus to form a closed inner cavity, and the nucleus pulposus is embedded in the inner cavity of the nucleus pulposus to simulate the elasticity of a natural nucleus pulposus;
The fiber ring consists of a collagen fiber matrix layer and collagen fibers, wherein the collagen fibers are in a cylindrical shape and are obliquely arranged in the collagen fiber matrix layer, the oblique directions of the adjacent two rows of collagen fibers are opposite, and the included angle between the collagen fibers and the upper surface and the lower surface of the fiber ring is 10-80 degrees;
the lower endplate comprises a lower endplate substrate and a plurality of sensors, the sensors are fixedly arranged on the outer side of the lower endplate substrate, and lower endplate fixing teeth are fixedly arranged on the outer side of the sensors.
The cross sections of the upper end plate, the intervertebral disc core and the lower end plate are 3D.
The included angle between the collagen fiber and the upper and lower surfaces of the fiber ring is 45 degrees.
The collagen fiber matrix layer and the collagen fibers are respectively printed out in a 3D way, and the collagen fibers are crossed and arranged in the collagen fiber matrix layer in a penetrating manner.
The collagen fiber matrix layer and the collagen fiber are synchronously printed into a whole by adopting a double-nozzle 3D printer.
The sensors of the lower end plate are three groups, namely a first sensor, a second sensor and a third sensor, wherein a plurality of protrusions are arranged on the first sensor, the second sensor and the third sensor, a plurality of through holes are formed in the base of the lower end plate, the size and the number of the protrusions are corresponding to those of the through holes, and the sensors and the base of the lower end plate are fixedly arranged together through interference of the protrusions and the through holes.
The upper endplate, the collagen fiber matrix layer, the collagen fibers and the nucleus pulposus are made of polymer materials.
The sensor of the lower end plate is made of conductive polymer materials.
The material of the sensor of the lower end plate is either polylactic acid doped with carbon black or carbon fiber doped with carbon black or acrylonitrile-styrene-butadiene copolymer doped with carbon black.
The working process and the working principle of the invention are as follows:
In the static, standing or sitting state of the human body, the upper end plate, the intervertebral disc core and the lower end plate of the invention are acted by vertical pressure to cause compression deformation of the intervertebral disc core in a certain direction, and then keep the structure stable. In the process, the contact area between the collagen fiber matrix layer and the collagen fiber is changed within a certain range, and electrons are transferred between contact interfaces based on the coupling effect of friction electrification and electrostatic induction to form potential difference. When in a stable state, the charge between the collagen fiber matrix layer and the collagen fibers is in an electrostatic balance state, and the voltage signal is kept constant.
When in motion, complex movements of the spine (including anterior-posterior extension, lateral flexion, axial rotation and translation) result in external loads acting on the upper or lower endplates, which in turn induce a compressive expansion of the disc core. On the microscopic level, the deformation promotes the collagen fiber matrix layer to be in closer contact with the collagen fibers, electrons are transferred between contact interfaces based on the coupling effect of friction electrification and static induction, potential difference is formed, and pulse signals are output. In the process, the pressure and the potential difference show a linear proportional relation, namely the contact area is increased due to the increase of the pressure, so that more charge accumulation is generated, and a larger induced electric potential difference is formed. Thus, the value of the external load currently applied can be deduced from the open circuit voltage peak.
In order to realize the omnidirectional dynamic monitoring of the spinal motion state, the collagen fiber is correspondingly connected with a plurality of sensor subareas. These sensors utilize the conductive properties of the material to transmit voltage signals from different areas in real time. By comparing and analyzing the differences of the voltage signals, the movement direction of the spine can be accurately identified. In addition, a linear proportional relation is also established between the angle of the spinal flexion and extension and the open-circuit voltage peak value, so that the angle of the spinal flexion and extension can be calculated by measuring the voltage peak value. Meanwhile, the frequency of the spinal motion corresponds to the pulse frequency of the open-circuit voltage, and the number of times of flexion and extension of the spinal can be recorded by counting the pulse frequency. The electric energy generated by the process is completely converted by the mechanical energy generated during the movement of the human body.
The pulse signal differences between the plurality of sensors can be used to identify the direction of motion of the spine, including static compression, dorsiflexion, lateral flexion, axial rotation and translation.
The extracted signals can be converted into digital information after being processed by the signal processing device according to the matching relation with external load, direction, bending and stretching angle and bending and stretching times, so that the dynamic monitoring of the parameters is realized, the related parameters can be displayed in a display screen, and the related parameters can be sent to terminal equipment for a patient or a doctor to check at any time.
The pulse signal and the external load applied to the current intervertebral disc show a linear proportional relation.
The pulse signal and the spine Qu Shenjiao degrees show a linear proportional relationship.
The pulse frequency of the pulse signal and the spinal motion frequency show a linear proportional relation.
The core components of the signal processing device include, but are not limited to, various Microcontrollers (MCUs), such as widely used singlechips of 51 series, STM32 series, and the like, and other integrated circuits with similar processing capabilities. The processed data can be directly displayed through an integrated display screen, and the connection between the display screen and the signal processing device can adopt a wired or wireless mode, so that the high efficiency and stability of data transmission are ensured.
In addition, the data may also be remotely sent to a terminal device, such as a smart phone, a tablet computer, etc., including but not limited to Bluetooth (Bluetooth), loRa (Long Range Radio), RF24L01, etc., and other efficient, low-power wireless communication technologies that may occur in the future. In view of modularization and expandability of the signal processing apparatus, the display screen and the wireless communication module may be configured simultaneously in addition to a single configuration.
The omnidirectional dynamic monitoring function provides individualized rehabilitation training guiding basis for doctors, helps patients to master the rehabilitation state of the patients in real time, and timely discovers and early warns potential abnormality or recurrence risk, so that early intervention measures are taken to promote rehabilitation progress.
The invention has the beneficial effects that:
1. In the invention, in the processes of static compression, forward flexion and backward extension, lateral flexion, axial rotation and translational movement of the spine, charge transfer occurs between the collagen fiber matrix layer and the collagen fiber based on the friction electrification and electrostatic induction coupling principle, and the charge transfer is converted into a high-sensitivity voltage signal through the electric connection between the end plate and an external load, so that the multidirectional stress condition of the intervertebral disc in the spinal activity is effectively perceived. Compared with the existing artificial intervertebral disc or bionic intervertebral disc, the artificial intervertebral disc or bionic intervertebral disc does not need to be additionally provided with or packaged with a sensor.
2. The invention divides the sensing area through the lower end plate, and decouples various sensing anisotropic characteristics of the bionic intervertebral disc.
3. The electric signals generated by the invention are all converted from mechanical energy generated in the human spinal column movement process, and no additional power supply or chemical battery is needed for supplying power.
4. The invention has good biocompatibility, low manufacturing cost, simple and easily obtained materials, simple process steps and easy individuation.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Fig. 2 is a schematic diagram of an upper endplate structure according to an embodiment of the invention.
Fig. 3 is a schematic structural view of an intervertebral disc core according to an embodiment of the present invention.
Fig. 4 is a schematic structural view of an embodiment of the fiber ring of the present invention.
Fig. 5 is a schematic bottom view of the structure of the lower endplate of an embodiment of the present invention.
Fig. 6 is a schematic diagram illustrating a disassembled structure according to an embodiment of the invention.
FIG. 7 is a graph showing the relationship between the pulse signal and the external load applied to the disc according to an embodiment of the present invention.
FIG. 8 is a graph showing the relationship between pulse signal and spinal extension angle according to an embodiment of the present invention.
FIG. 9 is a graph of pulse frequency versus spinal motion frequency for a pulse signal according to an embodiment of the present invention.
Detailed Description
Referring to fig. 1 to 9, an embodiment of the present invention is shown.
The personalized self-monitoring intelligent bionic intervertebral disc for in-vivo service movement and stress state comprises an upper endplate 1, an intervertebral disc core 2 and a lower endplate 3, wherein the cross sections of the upper endplate 1, the intervertebral disc core 2 and the lower endplate 3 are D-shaped.
The upper endplate 1 is provided with upper endplate fixed teeth 11, and the upper endplate fixed teeth 11 are used for being connected and fixed with adjacent vertebral bodies to prevent sinking;
the intervertebral disc core 2 comprises an annulus fibrosis 21 and a nucleus pulposus 22, wherein the annulus fibrosis 21 is used as a peripheral structure of the intervertebral disc core 2 to form a closed inner cavity, the nucleus pulposus 22 is embedded in the inner cavity of the annulus fibrosis 21 to simulate the elasticity of a natural nucleus pulposus, and the nucleus pulposus 22 is prepared by adopting a thermoplastic polyurethane elastomer 87A;
The fiber ring 21 consists of a collagen fiber matrix layer 211 and collagen fibers 212, wherein the collagen fibers 212 are in a cylindrical shape and are obliquely arranged in the collagen fiber matrix layer 211, the oblique directions of the adjacent two rows of collagen fibers 212 are opposite, the included angle between the collagen fibers 212 and the upper surface and the lower surface of the fiber ring 21 is 45 degrees, the collagen fiber matrix layer 211 adopts a thermoplastic polyurethane elastomer 95A, the collagen fibers 212 adopt polylactic acid doped with carbon black, and a double-nozzle 3D printer is used for synchronously printing into a whole.
The lower endplate 3 includes a lower endplate base 31 and three sensors 32, a first sensor 321, a second sensor 322, and a third sensor 323, respectively;
The first sensor 321, the second sensor 322 and the third sensor 323 are fixedly arranged on the outer side of the lower endplate base 31, the lower endplate fixing teeth 33 are fixedly arranged on the outer sides of the first sensor 321, the second sensor 322 and the third sensor 323, and the lower endplate fixing teeth 33 are used for being fixedly connected with adjacent vertebral bodies to prevent sinking.
The first sensor 321, the second sensor 322 and the third sensor 323 are provided with a plurality of protrusions 324, the lower endplate substrate 31 is provided with a plurality of through holes 311, the protrusions 324 and the through holes 311 are corresponding in size and number, and the first sensor 321, the second sensor 322 and the third sensor 323 are respectively and fixedly arranged with the lower endplate substrate 31 through interference of the protrusions 324 and the through holes 311. The materials of the first sensor 321, the second sensor 322 and the third sensor 323 are prepared from polylactic acid doped with carbon black. The material of the three sensors has conductive properties and forms a conductive path with the collagen fibers 212.
The lower endplate substrate 31 is made of polylactic acid to prevent electrical signal interference between the three sensors.
The collagen fiber matrix layer 211, collagen fibers 212, and the nucleus pulposus 22 are prepared using a polymer material.
The working process and working principle of the embodiment:
In the resting, standing or sitting state of the human body, the upper endplate 1, the disc core 2 and the lower endplate 3 of this embodiment are subjected to vertical pressure, causing compressive deformation of the disc core 2 in a certain direction, and then maintaining structural stability. In this process, a contact area between the collagen fiber matrix layer 211 and the collagen fibers 212 is changed within a certain range, and electrons are transferred between contact interfaces based on a coupling effect of triboelectrification and electrostatic induction, so that a potential difference is formed. When in a stable state, the charge between the collagen fiber matrix layer 211 and the collagen fibers 212 is then in an electrostatic balance state, and the voltage signal is maintained constant.
When in motion, complex movements of the spine (including flexion-extension, lateral bending, axial rotation and translation) result in external loads acting on the upper endplate 1 or the lower endplate 3, which in turn cause compression expansion of the disc core 2. At the microscopic level, this deformation promotes closer contact between the collagen fiber matrix layer 211 and the collagen fibers 212, and electrons are transferred between the contact interfaces based on the coupling effect of triboelectrification and electrostatic induction, forming a potential difference. In the process, the pressure and the potential difference show a linear proportional relation, namely the contact area is increased due to the increase of the pressure, so that more charge accumulation is generated, and a larger induced electric potential difference is formed. Thus, the value of the external load currently applied can be deduced from the open circuit voltage peak.
To achieve an omnidirectional dynamic monitoring of the spinal motion state, the collagen fibers 212 are connected to the first sensor 321, the second sensor 322 and the third sensor 323 in a zoned manner. The three sensors utilize the conductive properties of the material to transmit voltage signals from different areas in real time. By comparing and analyzing the differences of the voltage signals, the movement direction of the spine can be accurately identified. For example, the third sensor 323 region outputs a higher voltage signal due to a larger deformation in the backward movement, and the first sensor 321 region signal is more remarkable in the left side bending.
In addition, a linear proportional relation is also established between the angle of the spinal flexion and extension and the open-circuit voltage peak value, so that the angle of the spinal flexion and extension can be calculated by measuring the voltage peak value. Meanwhile, the frequency of the spinal motion corresponds to the pulse frequency of the open-circuit voltage, and the number of times of flexion and extension of the spinal can be recorded by counting the pulse frequency. The electric energy generated by the process is completely converted by the mechanical energy generated during the movement of the human body.
It should be noted that, according to the above-mentioned matching relation with external load, direction, angle of extension and number of extension, the extracted signal can be processed by signal processing device and converted into digital information, so as to implement dynamic monitoring of the above-mentioned parameters, and the related parameters can be displayed in display screen, also can be sent to terminal equipment, and can be used for patient or doctor to check at any time. The core components of the signal processing device include, but are not limited to, various Microcontrollers (MCUs), such as but not limited to, widely-used single-chip computers of 51 series, STM32 series and the like, and other integrated circuits with similar processing capabilities. The processed data can be directly displayed through an integrated display screen, and the connection between the display screen and the signal processing device can adopt a wired or wireless mode, so that the high efficiency and stability of data transmission are ensured. In addition, the data may also be remotely sent to a terminal device, such as a smart phone, a tablet computer, etc., including but not limited to Bluetooth (Bluetooth), loRa (Long Range Radio), RF24L01, etc., and other efficient, low-power wireless communication technologies that may occur in the future. In view of modularization and expandability of the signal processing apparatus, the display screen and the wireless communication module may be configured simultaneously in addition to a single configuration.
The omnidirectional dynamic monitoring function provides individualized rehabilitation training guiding basis for doctors, helps patients to master the rehabilitation state of the patients in real time, and timely discovers and early warns potential abnormal intervertebral motions and stress, so that individualized intelligent monitoring and rehabilitation promotion of the patients are realized.