RU2163090C1 - Method and device for carrying out humerus osteosynthesis - Google Patents

Abstract

FIELD: medicine; medical engineering. SUBSTANCE: method involves placing an insert into external acoustic canal to form air-proof chamber with air pressure changeable under control. Acoustic signal is sent in continuous mode to measure mechanical tension in the tympanic membrane, described by its acoustic compliance that is measured twice. Value calculated from formula

is the measure of intracranial pressure change during the time interval between two measurements, where ΔC_1,2 is the relative change of the tympanic membrane acoustic compliance during the time interval between the first and the second measurement. C₁(p $\genfrac{}{}{0ex}{}{\text{1}}{\text{0}}$ ), C₂(p $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ ) are the tympanic membrane acoustic compliance values in the first and the second measurement, respectively. p $\genfrac{}{}{0ex}{}{\text{1}}{\text{0}}$ , p $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ , are the air pressure values in the middle ear in the first and the second measurement, respectively. The device has insert for making air-proof chamber in the external acoustic canal, acoustic probe placed in the insert, air pump varying air pressure in the air-tight chamber in controlled manner, acoustic tone emitter, measuring microphone, measurement unit and control unit. The control unit is connected to the unit for measuring air pressure in the middle ear cavity through a unit for storing data, unit for transforming data to the common pressure scale and unit for measuring determining relative change of the tympanic membrane acoustic compliance. The insert has flexible casing with a cavity to be filled with compressed air. EFFECT: accelerated noninvasive measurement method; low costs. 2 cl, 2 dwg

Description

 The invention relates to medicine, namely, it is intended to determine changes in intracranial pressure.

 A known method of measuring intracranial pressure and a device for its implementation. The method includes the introduction of a pressure sensor hydraulically in communication with air injection and measurement systems, wherein air is injected into the pressure measurement system in equal doses in an amount of at least two, and the desired value is judged by changing the pressure increment, the elastic camera being used as the sensor folded state (1).

 This method is carried out during a surgical operation, when the sensor is folded inserted into the patient under the edge of the bone defect between the brain and the dura mater or between the meninges and the inner plate of the bones of the skull, that is, the known method is invasive for the patient.

 Closest to the proposed one is a method for determining changes in intracranial pressure, including installing an insert into the external ear canal to form a sealed chamber in it, creating air pressure in it using an air pump, and delivering a sound tone to affect the eardrum. And the device includes an insert for forming a sealed chamber in the external ear canal, an acoustic probe located in the insert, an air pump to create air pressure in the sealed chamber, an emitter of a sound tone, a measuring microphone, and a measurement and control unit (2).

 The disadvantages of this method and device are expensive equipment for implementing the method, the need for a patient to have a distinct acoustic reflex and normal pressure in the middle ear, and the duration of one measurement is 30-60 minutes.

 The tasks that are solved by the proposed invention, in comparison with the known ones, are non-invasive determination of changes in intracranial pressure with a significant reduction in its duration (less than 2 minutes), cheaper device for implementing the method, since the blocks included in the device are available.

где Δ C_1,2 - относительное изменение величины акустической податливости барабанной перепонки в интервале времени между первым и вторым измерениями, C₁(P₀ ¹), C₂(P₀ ²) - величины акустической податливости барабанной перепонки в первом и втором измерениях соответственно, P₀ ¹, P₀ ² - величины давления воздуха в полости среднего уха пациента в первом и втором измерениях соответственно.The problem is solved in that in a method for determining changes in intracranial pressure, including installing an insert in the external ear canal to form a sealed chamber in it, creating air pressure in it using an air pump, delivering a sound tone to affect the eardrum, air pressure in a sealed the chamber is dosed, and the sound tone is continuously produced to determine the mechanical tension of the eardrum, characterized by its acoustic flexibility, cat the second one is measured twice, and the measure of the change in the value of intracranial pressure in the time interval between two measurements is the relative change in the value of the acoustic compliance of the eardrum in the specified time interval, determined by the formula

where Δ C _1,2 is the relative change in the acoustic compliance of the tympanic membrane in the time interval between the first and second measurements, C ₁ (P ₀ ¹ ), C ₂ (P ₀ ² ) is the acoustic compliance of the eardrum in the first and second measurements, respectively , P ₀ ¹ , P ₀ ² - air pressure in the middle ear cavity of the patient in the first and second dimensions, respectively.

 A device for implementing the method, comprising an insert for forming an airtight chamber in the external ear canal, an acoustic probe located in the insert, connected to an air pump to create air in the airtight chamber, an acoustic emitter, a measuring microphone, and a measurement and control unit, provided a data storage unit, a unit for determining air pressure in the middle ear, a unit for bringing data to a single pressure scale, and a unit for determining regarding changes values of acoustic compliance of the eardrum, and the data storage unit is connected to the measurement and control unit, and the liner body is made elastic and has a cavity for filling with compressed air.

 In FIG. 1 is a diagram of a device for implementing a method for determining changes in intracranial pressure.

 In FIG. 2 is a diagram explaining the effect of intracranial pressure of the cerebrospinal fluid on the micromechanics of the middle ear.

 The device for implementing the method comprises (Fig. 1) a liner 1, the housing of which is elastic and has a cavity 2 for filling with compressed air. An acoustic probe 3 is placed in the housing of the insert 1. The acoustic probe 3 is connected to the sound tone emitter 4, the air pump 5 and the measuring microphone 6, which are connected to the measurement and control unit 7, the unit 7, in turn, is connected to the unit connected in series 8 data storage, block 9 determine the air pressure in the middle ear, block 10 bring the data to a single pressure scale and block 11 determine the relative change in the magnitude of the acoustic compliance of the tympanic membrane.

 The cochlear aqueduct 12 (Fig. 2), connecting the subarachnoid space of the posterior cranial fossa 12 with the tympanic ladder 14, is the main transmission channel of intracranial pressure (ICP) of the cerebrospinal fluid 15 into the perilymph of the inner ear 16. A change in the ICP (increase or decrease) is transmitted through cochlear water supply 12 to the perilymph of the inner ear 16, then to the base of the stapes 17 and then along the chain of auditory ossicles 18 to the eardrum 19. This changes the mechanical tension of the eardrum 19, which, being registered as a relative change in the acoustic compliance of the eardrum 19, serves in the present method as a measure of the change in ICP value. The outer ear canal is 20, the cavity of the middle ear is 21.

 The method for determining changes in intracranial pressure using the proposed device is as follows.

An insert 1 having an elastic body is inserted into the external ear canal 20 of the patient. Then in the cavity 2 of the liner 1 serves compressed air. In this case, the insert body is inflated, providing a reliable obturation of part of the external ear canal 20 with the formation of a sealed chamber. An acoustic probe 3, placed inside the insert 1, a continuous sound emitter 4, a measuring microphone 6, an air pump 5, and a measurement and control unit 7 provide measurement of the tympanogram T (p) - the dependence of the acoustic compliance of the formed sealed chamber on the air pressure in it during a dosed change the specified pressure with respect to atmospheric in the range from p _min to p _max with a pressure change step Δp. In this case, a metered change in air pressure in the formed airtight chamber is carried out using an air pump 5. The sound tone of frequency f at a fixed sound pressure level S in the formed airtight chamber is created by means of a continuous sound tone emitter 4, the sound pressure level in the formed airtight chamber is measured using the measuring microphone 6, the recording of the tympanogram T (p) is carried out by means of the measuring and control unit 7. The procedure for measuring the tympanogram is carried out in accordance with the rules adopted in audiological practice (preliminary otoscopic examination of the patient’s external ear canal, parameters: p _min = 300 mm water column, p _min = +200 mm water column, Δp = 5 mm water column, f = 226 Hz , S = 85 dB SPL).

где C₁(P₀ ¹), C₂(P₀ ²) - величины акустической податливости барабанной перепонки в первом и втором измерениях соответственно, P₀ ¹, P₀ ²) - величины давления воздуха в полости среднего уха пациента в первом и втором измерениях соответственно. Причем в приближении прямой пропорциональной зависимости между изменением величины ВЧД и относительным изменением величины акустической податливости барабанной перепонки, значению параметра Δ C_1,2 = -0,1 относительных единиц соответствует изменение ВЧД приблизительно на - 50 мм водного столба.Two tympanograms T ₁ (p) and T (p) are measured in a patient with a time interval Δt between measurements of the 1st and 2nd tympanograms. From the measurement and control unit, the recorded tympanograms T ₁ (p) and T ₂ (p) enter the data storage unit 8, in which they are stored. From block 8, tympanograms T ₁ (p) and T ₂ (p) enter block 9 for determining air pressure p ₀ in the middle ear cavity 21, and then to block 10 bringing tympanograms T ₁ (p) and T ₂ (p) to a single pressure scale p. From block 10, tympanograms T ₁ (p ^* ) and T ₂ (p ^* ) reduced to a single pressure p ^* are received in block 11 for determining the relative change in the acoustic compliance of the tympanic membrane ΔC _1,2 in the time interval between measurements of the 1st and 2nd th tympanogram determined according to the formula:

where C ₁ (P ₀ ¹ ), C ₂ (P ₀ ² ) are the acoustic compliance values of the eardrum in the first and second measurements, respectively, P ₀ ¹ , P ₀ ² ) are the air pressure in the middle ear cavity of the patient in the first and second measurements accordingly. Moreover, in the approximation of a direct proportional relationship between the change in the ICP value and the relative change in the magnitude of the acoustic compliance of the eardrum, the value of the parameter Δ C _1.2 = -0.1 relative units corresponds to a change in the ICP by approximately - 50 mm water column.

 The block and devices can be implemented as follows. Block 7 provides a record of the typogram in the form of a digital or analog electrical signal, and in conjunction with blocks 4, 5, and 6, is an acoustic compliance meter or acoustic impedance meter.

 Block 8 provides storage of the recorded tympanogram in the form of an electrical signal, presented in digital or analog form, and can be implemented as digital random access memory or analog memory, respectively.

The pressure in the middle ear cavity p ₀ is defined as the pressure in the external ear canal at which the tympanogram reaches its maximum value (as defined, for example, "Essentials of Audiology", Gelfand SA, Thieme, Ny-Stuttgard, 1997, p. 228). Therefore, the pressure unit in the middle ear cavity can be implemented as a digital device for determining the number of an array element with a maximum value, or a peak value detector of an analog signal with a digital or analog form of representation of a tympanogram, respectively.

 The procedure for bringing tympanograms to a single pressure scale in terms of tympanometry means shifting each tympanogram along the pressure axis by the amount of pressure in the middle ear cavity. The indicated action is carried out by block 10, which can be implemented as a shift register in the digital form of representation of tympanograms or as an analog subtractive device in the analog form of representation.

 Block 11 can be performed as a digital computing device that implements the conversion function according to the formula above. When presenting tympanograms in the form of an analog electrical signal, block 11 can be implemented as a combination of an analog subtractor and an analog divider.

Example 1. Patient B., 12 years old, was hospitalized with signs of an increase in ICP due to impaired functioning of the shunt system installed earlier (hypertensive hydrocephalus). An ophthalmoscopic examination revealed stagnation of the optic nerve disks. Computed tomography (CT) revealed a shunt displacement. Two tympanograms were taken from each patient’s ear - the first immediately before the operation (revision of the drainage system), the second on the 2nd day after it. To assess the effectiveness of surgical intervention and study the dynamics of ICP using the proposed device, the ΔC _1,2 parameters were determined for the right and left ear. For the right ear, the ΔC _1.2 parameter value was -0.2 ± 0.03 rel. units, for the left ear - 0.15 ± 0.02 rel. units Based on what, it was concluded that there was a significant (≈100 mm in st.) Reduction in ICP, later confirmed by repeated ophthalmoscopy and CT. In order to monitor the status of the shunt system, the patient is recommended to conduct periodic measurements of ΔC _1,2 .

Example 2. Patient Sh., 11 years old, was hospitalized with signs of increased ICP due to impaired functioning of the shunt system installed earlier (hypertensive hydrocephalus). An ophthalmoscopic examination revealed a decrease in visual function due to a descending atrophy of the optic nerves. With CT, there is an increase in ventriculomegania, subarachnoid spaces are not traced. Two tympanograms were taken from each patient’s ear - the first immediately before the operation (revision of the drainage system), the second on the 2nd day after it. To assess the effectiveness of surgical intervention and study the dynamics of ICP using the proposed device, the ΔC _1,2 parameters were determined for the right and left ear. For the right ear, the ΔC _1.2 parameter value was -0.07 ± 0.02 rel. units for the left ear -0.1 ± 0.02 rel. units Based on what, it was concluded that there was a moderate (≈50 mm in st.) Decrease in ICP, later confirmed by data of repeated CT. Upon discharge, the patient is recommended to conduct periodic measurements of ΔC _1,2 to monitor the condition of the drainage system.

 Thus, the proposed method and device for its implementation allows for non-invasive determination of changes in ICP with a significant reduction in material costs and time.

Sources of information
1. USSR author's certificate N 1022698, A 61 B 5/03, 1983.

 2. U.S. Patent No. 4,841,986, A 61 B 5/12, 1989.

Claims (2)

1. A method for determining changes in intracranial pressure, including installing an insert in the external ear canal to form a sealed chamber in it, creating air pressure in it using an air pump, delivering an audible tone, characterized in that the air pressure in the chamber is changed in a measured manner, delivering an audible tone produce continuously, register two tympanograms with a time interval between measurements, find the relative change in the magnitude of the acoustic compliance of the tympanic membrane according to the formula

where Δ C _1,2 is the relative change in the magnitude of the acoustic compliance of the eardrum in the time interval between the first and second measurements;
C ₁ (P ₀ ¹ ), C ₂ (P ₀ ² ) are the acoustic compliance values of the eardrum in the first and second dimensions, respectively;
P ₀ ¹ , P ₀ ² - air pressure in the middle ear cavity of the patient in the first and second measurements, respectively,
and the value of Δ C _1,2 is a measure of the change in the value of intracranial pressure.  2. A device for determining changes in intracranial pressure, including an insert for forming a sealed chamber in the external ear canal, an acoustic probe located in the insert, connected to an air pump to create air pressure in the sealed chamber, an acoustic emitter, a measuring microphone, and a measurement and control unit characterized in that the device is equipped with a data storage unit, a unit for determining air pressure in the middle ear cavity, a drive unit, connected in series with each other data to a single pressure scale and a unit for determining the relative measurement of the acoustic compliance of the tympanic membrane, the data storage unit being connected to the measuring and control unit, and the liner body made elastic and has a cavity for filling with compressed air.

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