CN105832327A - Embedded wireless passive intracranial pressure monitoring system - Google Patents

Abstract

The present invention provides an implantable wireless passive intracranial pressure monitoring system, comprising: an intracranial pressure sensor for sensing the intracranial pressure value, an external patch reader for generating mutual inductance coupling with the intracranial pressure sensor, and detecting The instrument is connected with an external patch reader to detect the resonant frequency of the intracranial pressure sensor to obtain the intracranial pressure value. The implantable wireless passive intracranial pressure monitoring system of the present invention does not need wires and catheters to be connected to external devices, avoids the risk of intracranial infection, and does not limit the normal activities of patients; it does not need to be powered by batteries, and can Realize long-term monitoring; the pressure-sensitive capacitor of the LC resonant pressure sensor is a MEMS structure, which is small in size and low in cost; the in vitro patch reader uses a flexible PCB printed coil, which is light in weight, thin in thickness and has good bendability. It will not cause discomfort to the patient.

Description

An implantable wireless passive intracranial pressure monitoring system

technical field

The invention relates to the technical field of medical devices, in particular to an implantable wireless passive intracranial pressure monitoring system.

Background technique

Intracranial pressure refers to the pressure generated by the contents of the cranial cavity on the wall of the cranial cavity, and is an important observation index for clinical diagnosis and treatment of neurosurgery. Normal intracranial pressure ranges from 70 to 180mmH ₂ O. When intracranial pressure continues to exceed 180mmH ₂ O for more than 5 minutes, it is clinically called increased intracranial pressure. Increased intracranial pressure can lead to a series of physiological dysfunction and pathological changes, manifested as typical manifestations such as headache, nausea, vomiting, and papilledema. Severe intracranial hypertension can also be complicated by complications such as pulmonary edema and hypertensive crisis, and can also cause autonomic dysfunction and life-threatening in a short period of time. It is the main cause of death caused by neurological and surgical diseases. Therefore, timely and accurate monitoring of intracranial pressure in patients is of great significance for clinical diagnosis and treatment guidance.

Intracranial pressure monitoring methods can be divided into implantable monitoring methods and non-implantable monitoring methods according to whether sensors are implanted into the skull. Among them, the non-implantable intracranial pressure monitoring method does not need to implant sensors in the brain, can avoid the trauma caused by implanted monitoring to patients, and has no risk of infection during the monitoring process, and has the advantages of simple operation and low cost . At present, non-implantable monitoring methods mainly include the following six methods: transcranial Doppler method, flash visual evoked potential method, tympanic membrane displacement method, anterior halogen manometry method, electrical impedance equivalent circuit model method and infrared spectroscopy Law. The above non-implantable monitoring methods all convert other physical quantities into pressure values through indirect means. There are many interference factors in the measurement principle and monitoring process, resulting in large measurement errors, so they have not yet been widely used in clinical practice.

The implantable intracranial pressure monitoring method refers to implanting a pressure sensor into the skull to directly measure the intracranial pressure value. At present, the clinically applied implantable monitoring methods can be divided into two categories: ventricular method and epidural method. According to the measurement principle, they can be divided into: hydraulic type, piezoresistive type, optical fiber type, etc. Fig. 1 shows 5 implantable intracranial pressure monitoring methods and locations widely used in the prior art, which are intraventricular implanted catheter 11, subarachnoid implanted catheter 12, epidural implanted sensor 13, Subdural implantation of catheter 14 and subdural implantation of screw 15. Taking the most widely used hydraulic ventricular manometry as an example, the specific implementation of the implanted monitoring method is introduced: the method is to drill holes in the skull, One end of the catheter is inserted into the ventricle, and the other end is connected to an external hydraulic sensor to measure intracranial pressure. The advantage of this method is that the detection accuracy is high, which can meet the requirements of clinical intracranial pressure monitoring indicators, and is regarded as the "gold standard" for intracranial pressure monitoring. However, this method and other existing implanted intracranial pressure monitoring devices are wired, and there are many inconveniences in the continuous monitoring process.

Contents of the invention

(1) Technical problems to be solved

To solve the above problems, the present invention provides an implantable wireless passive intracranial pressure monitoring system.

(2) Technical solutions

The present invention provides an implantable wireless passive intracranial pressure monitoring system, comprising: an intracranial pressure sensor 21 for sensing the intracranial pressure value, and its resonant frequency changes with the change of the intracranial pressure value; The reader 31, based on the principle of electromagnetic induction coupling, generates mutual inductance coupling with the intracranial pressure sensor 21, and its impedance spectrum changes at the resonant frequency of the intracranial pressure sensor; the detection instrument 41 is connected to the external patch type The reader 31 detects the change of the impedance spectrum of the patch reader outside the body, obtains the resonant frequency of the intracranial pressure sensor through impedance analysis, and obtains the intracranial pressure value.

Preferably, the intracranial pressure sensor 21 is an LC resonant pressure sensor, which is implanted in the cranium, and includes: a shell and an inductance and a pressure-sensitive capacitor inside the shell, wherein the inductance and the pressure-sensitive capacitor form an LC oscillation circuit.

Preferably, the external patch reader 31 includes a flexible PCB 32 and a coil 33 printed on the flexible PCB, wherein the diameter of the coil is larger than the diameter of the inductance of the LC resonant pressure sensor, and the external patch reader The reader 31 is pasted on the scalp directly above the position where the intracranial pressure sensor is implanted, and the coil 33 is directly opposite to the inductance position of the LC resonant pressure sensor.

Preferably, the detection instrument 41 is connected to the coil 33 of the external patch reader through wires.

Preferably, the housing of the LC resonant pressure sensor is a two-stage structure, including: a large diameter part 22 and a small diameter part 23; wherein, the inductance of the LC resonant pressure sensor is placed on the large diameter part 22, and its pressure sensitive capacitance is placed on the The small-diameter part 23 and the large-diameter part 22 are placed within the scope of the skull, and the small-diameter part 23 is placed in the ventricle, and the diameter of the small-diameter part is smaller than that of the large-diameter part.

Preferably, there is a rectangular window at the place where the pressure-sensitive capacitor is placed in the small diameter portion, so that the pressure-sensitive capacitor communicates with the intracranial environment and senses intracranial pressure.

Preferably, the shell is made of polytetrafluoroethylene.

Preferably, the large-diameter portion 22 and the small-diameter portion 23 are connected by internal and external threads; and/or at the seam between the pressure-sensitive capacitor and the rectangular window, and at the seam between the large-diameter portion 22 and the small-diameter portion 23 , coated with epoxy adhesive bonding seal.

Preferably, the pressure-sensitive capacitor is a MEMS structure, which is processed by MEMS technology.

Preferably, the detection instrument 41 has a display screen to display the intracranial pressure value in real time.

(3) Beneficial effects

It can be seen from the above technical solution that an implantable wireless passive intracranial pressure monitoring system of the present invention has the following beneficial effects:

(1) The pressure sensor is implanted in the cranium without the need for wires and catheters to connect with external devices, avoiding the risk of intracranial infection during the monitoring process, and will not limit the normal activities of patients due to the existence of wires and catheters;

(2) The intracranial pressure sensor does not need to be powered by any form of power supply such as batteries, so it can realize long-term monitoring, and the heat generated during the work is extremely small, which will not cause discomfort to the patient;

(3) The pressure-sensitive capacitor of the LC resonant pressure sensor is a MEMS structure, which is processed by MEMS technology. The intracranial pressure sensor is small in size, which can meet the clinical size requirements for implanted sensors, and the cost is low, which is convenient for clinical use. promotional use;

(4) The in vitro patch reader uses a flexible PCB printed coil, which is light in weight, thin in thickness and has good bendability, and can be pasted on the patient's scalp without causing discomfort to the patient.

Description of drawings

Fig. 1 is a schematic diagram of an implantable intracranial pressure monitoring method and its location widely used in the prior art;

2 is a schematic structural diagram of an implantable wireless passive intracranial pressure monitoring system according to an embodiment of the present invention;

Fig. 3 is a working principle diagram of the implantable wireless passive intracranial pressure monitoring system according to the embodiment of the present invention;

Fig. 4 (a), Fig. 4 (b), Fig. 4 (c) are respectively the front view, the left view and the 3D rendering of the shell of the embodiment of the present invention;

Fig. 5 is a schematic structural diagram of an in vitro patch reader according to an embodiment of the present invention.

【Symbol Description】

11-intraventricular implanted catheter; 12-subarachnoid implanted catheter; 13-epidural implanted sensor; 14-subdural implanted catheter; 15-subdural implanted screw;

21-intracranial pressure sensor; 22-large diameter part; 23-small diameter part;

31-In vitro patch reader; 32-Flexible PCB; 33-Coil;

41 - detection instrument;

R _S - internal resistance; L _S - inductance; C _S - pressure sensitive capacitance; L _R - coil inductance.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

As shown in Figure 2, the embodiment of the present invention provides an implantable wireless passive intracranial pressure monitoring system, which can realize long-term intracranial pressure monitoring, which includes:

The intracranial pressure sensor 21 is used to sense the intracranial pressure value, and its resonant frequency changes with the change of the intracranial pressure value;

The external patch reader 31, based on the principle of electromagnetic induction coupling, generates mutual inductance coupling with the intracranial pressure sensor 21, and its impedance spectrum changes at the resonant frequency of the intracranial pressure sensor;

The detection instrument 41 is connected to the external patch reader 31, and detects the change of the impedance spectrum of the external patch reader, obtains the resonance frequency of the intracranial pressure sensor through impedance analysis, and deduces the intracranial pressure value.

The structure and working principle of each component of the implantable wireless passive intracranial pressure monitoring system of the present application will be described in detail below.

The intracranial pressure sensor 21 is an LC resonant pressure sensor, which includes: the shell and the inductance and pressure-sensitive capacitor in the shell. The inductance and the pressure-sensitive capacitor form an LC oscillation circuit. The intracranial pressure sensor 21 is implanted in the skull, and its pressure-sensitive capacitor The capacitance value of the LC resonant pressure sensor can change with the change of the intracranial pressure value, and the change of the capacitance value causes the resonant frequency of the LC oscillation circuit of the LC resonant pressure sensor to change. As shown in Figure 3, the inductance L _S and the pressure-sensitive capacitor C _S form an LC oscillating circuit, and R _S is the internal resistance of the LC oscillating circuit.

Preferably, the pressure-sensitive capacitance of the LC resonant pressure sensor is a MEMS structure, which is processed by MEMS technology. The intracranial pressure sensor 21 is small in size, which can meet the clinical size requirements for implanted sensors, and has low cost, which is convenient for clinical use. Promoted use.

As shown in Figure 5, the external patch reader 31 includes a flexible PCB 32 and a coil 33 printed on the flexible PCB, the coil diameter is greater than the diameter of the inductance of the LC resonant pressure sensor, and the external patch reader 31 is pasted Implant the intracranial pressure sensor directly above the scalp, so that the coil 33 is directly opposite to the inductance of the LC resonant pressure sensor. The resonance frequency of the LC oscillation circuit of the pressure sensor changes, and the impedance phase angle of the coil becomes concave. As shown in FIG. 3 , the coil inductance _LR of the in vitro patch reader is electrically connected to the detection instrument.

The external patch reader 31 adopts a flexible PCB 32 to print a coil 33, which is light in weight, thin in thickness and good in bendability, and can be pasted on the patient's scalp without causing discomfort to the patient.

The detection instrument 41 is connected to the coil of the external patch reader through a wire, and measures the impedance change of the external patch reader coil, and obtains the resonance frequency of the LC oscillation circuit of the LC resonant pressure sensor through impedance analysis, thereby calculating The corresponding intracranial pressure value.

Preferably, the detection instrument 41 may have a display screen to display the calculated intracranial pressure value in real time, so that the medical staff can intuitively obtain the measurement result.

In the implantable wireless passive intracranial pressure monitoring system of the embodiment of the present invention, the pressure sensor is implanted in the skull, and no wires and catheters are needed to connect with external equipment, which avoids the risk of intracranial infection during the monitoring process, and at the same time, it will not be caused by wires. The normal activities of the patient are limited by the presence of catheters. The intracranial pressure sensor does not need to be powered by any form of power supply such as batteries, so it can realize long-term monitoring, and the heat generated during the work is extremely small, which will not cause discomfort to the patient.

In another embodiment of the present invention, as shown in Fig. 4(a), Fig. 4(b) and Fig. 4(c), the shell of the LC resonant pressure sensor is a two-stage structure, including a large diameter part 22 and In the small diameter part 23 , the inductance of the LC resonant pressure sensor is placed in the large diameter part 22 , and the pressure sensitive capacitor is placed in the small diameter part 23 .

The large-diameter part 22 is placed within the scope of the skull, that is, between the scalp and the dura, and its diameter is preferably 12 mm, and its height is preferably less than or equal to 10 mm, so that the large-diameter part 22 is completely placed within the scope of the skull, and its wall thickness should be as small as possible. To reduce the influence of inductive coupling.

The small-diameter part 23 is placed in the ventricle, that is, pierces the pia mater, and is implanted into the brain tissue. Its diameter is smaller than the diameter of the large-diameter part, preferably 5-10 mm, and its height is preferably 50-60 mm, so that the pressure-sensitive capacitor is placed at the most sensitive pressure. For optimal depth, open a rectangular window at the place where the pressure-sensitive capacitor is placed, so that the pressure-sensitive capacitor can communicate with the intracranial environment to sense intracranial pressure.

Preferably, the large-diameter part 22 and the small-diameter part 23 of the LC resonant pressure sensor housing are connected by internal and external threads; at the seam between the pressure-sensitive capacitor and the rectangular window and between the large-diameter part 22 and the small-diameter part 23 All places are coated with epoxy adhesive for bonding and sealing; the shell is made of polytetrafluoroethylene material, which has good biocompatibility and extremely low coefficient of friction, which is conducive to implanting the sensor into the skull and will not interfere with brain tissue. Produce a rejection reaction.

The implantable wireless passive intracranial pressure monitoring system of the present invention, its specific use method comprises the following steps:

Step A: Drill a hole at a suitable position on the top of the skull with a diameter of 12 mm, and implant the intracranial pressure sensor 21 into the skull. During the implantation process, it is necessary to ensure that the large diameter part 22 of the LC resonant pressure sensor shell is placed within the skull Inside, that is, between the scalp and the dura mater, place the small diameter part 23 of the LC resonant pressure sensor shell in the ventricle, that is, penetrate the pia mater, and implant the brain tissue. After the sensor is implanted, the scalp is sutured;

Step B: Paste the external patch reader 31 on the scalp directly above the position where the intracranial pressure sensor is implanted;

Step C: When the patient's intracranial pressure needs to be monitored, the medical personnel connect the external patch reader 31 to the detection instrument 41, and the detection instrument 41 can display the intracranial pressure value in real time. After the monitoring is completed, the medical personnel only need to disconnect the external patch reader 31 from the detection instrument 41 . When performing subsequent intracranial pressure monitoring, it is only necessary to repeat step three, that is, to directly connect the external patch reader 31 to the detection instrument 41 for detection.

It should be noted that, in the accompanying drawings or in the text of the specification, implementations that are not shown or described are forms known to those of ordinary skill in the art, and are not described in detail. In addition, the above definitions of each element and step are not limited to the various specific structures, shapes and steps mentioned in the embodiments, and those skilled in the art can easily modify or replace them, for example:

(1) This document may provide examples of parameters that include specific values, but these parameters need not be exactly equal to the corresponding values, but may approximate the corresponding values within acceptable error tolerances or design constraints;

(2) The directional terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only referring to the directions of the drawings, and are not used to limit The protection scope of the present invention;

(3) The above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, technical features in different embodiments can be freely combined to form more embodiments.

In summary, in the implantable wireless passive intracranial pressure monitoring system of the present invention, the pressure sensor is implanted in the brain without the need for wires and catheters to connect with external devices, which avoids the risk of intracranial infection during the monitoring process, and at the same time does not Due to the existence of wires and catheters, the normal activities of patients will be restricted; the intracranial pressure sensor does not need to be powered by any form of power such as batteries, so it can achieve long-term monitoring, and the heat generated during work is extremely small, and will not damage the The patient feels uncomfortable; the pressure-sensitive capacitor of the LC resonant pressure sensor is a MEMS structure, which is processed by MEMS technology. It is popularized and used in clinical practice; the in vitro patch reader uses a flexible PCB printed coil, which is light in weight, thin in thickness and has good bendability, and can be pasted on the patient's scalp without causing discomfort to the patient.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. An implantable wireless passive intracranial pressure monitoring system, characterized in that it comprises: The intracranial pressure sensor (21) is used for sensing the intracranial pressure value, and its resonant frequency changes with the change of the intracranial pressure value; The external patch reader (31), based on the principle of electromagnetic induction coupling, generates mutual inductance coupling with the intracranial pressure sensor (21), and its impedance spectrum changes at the resonant frequency of the intracranial pressure sensor; A detection instrument (41), which is connected to the in vitro patch reader (31), detects changes in the impedance spectrum of the in vitro patch reader, obtains the resonant frequency of the intracranial pressure sensor through impedance analysis, and obtains the intracranial Pressure value. 2. The implantable wireless passive intracranial pressure monitoring system as claimed in claim 1, wherein the intracranial pressure sensor (21) is an LC resonant pressure sensor, which is implanted in the cranium, comprising: a shell And the inductance and the pressure-sensitive capacitor in the casing, wherein the inductance and the pressure-sensitive capacitor form an LC oscillation circuit. 3. The implantable wireless passive intracranial pressure monitoring system as claimed in claim 2, characterized in that, the external patch reader (31) comprises a flexible PCB (32) and is printed on the flexible PCB. The coil (33), wherein, The diameter of the coil is greater than the diameter of the inductance of the LC resonant pressure sensor, and the in vitro patch reader (31) is pasted on the scalp directly above the position of the intracranial pressure sensor, and the coil (33) is connected to the LC The inductance of the resonant pressure sensor is directly opposite. 4. The implantable wireless passive intracranial pressure monitoring system according to claim 3, characterized in that, the detection instrument (41) is connected to the coil (33) of the external patch reader through a wire. 5. The implantable wireless passive intracranial pressure monitoring system as claimed in claim 2, characterized in that, the shell of the LC resonant pressure sensor is a two-stage structure, comprising: a large diameter part (22) and a small diameter Part (23); of which, The inductance of the LC resonant pressure sensor is placed in the large-diameter part (22), the pressure-sensitive capacitor is placed in the small-diameter part (23), the large-diameter part (22) is placed in the skull, and the small-diameter part (23) is placed in the ventricle. The diameter of the portion is smaller than the diameter of the large diameter portion. 6. The implantable wireless passive intracranial pressure monitoring system as claimed in claim 5, characterized in that, there is a rectangular window at the place where the pressure-sensitive capacitor is placed in the small-diameter part, so that the pressure-sensitive capacitor communicates with the intracranial environment, and senses Measure intracranial pressure. 7. The implantable wireless passive intracranial pressure monitoring system according to claim 6, wherein the shell is made of polytetrafluoroethylene. 8. The implantable wireless passive intracranial pressure monitoring system according to claim 7, characterized in that, the large diameter part (22) and the small diameter part (23) are connected by internal and external threads; The seams between the capacitor and the rectangular window, and the seams between the large diameter part (22) and the small diameter part (23) are coated with epoxy adhesive for bonding and sealing. 9. The implantable wireless passive intracranial pressure monitoring system according to claim 2, wherein the pressure-sensitive capacitor is a MEMS structure, which is processed by MEMS technology. 10. The implantable wireless passive intracranial pressure monitoring system according to claim 4, characterized in that, the detection instrument (41) has a display screen to display the intracranial pressure value in real time.