JPH0751277A - Skull boring monitoring device - Google Patents

Abstract

PURPOSE:To increase the safety and the reliability of the skull opening operation, by extracting only the receiving signal in a specific time width as to a surface acoustic wave transmitting in a skull by an ultrasonic wave, and comparing the received signal with a specific threshold value as well as integrating the signal of the transmitting energy of the surface acoustic wave, so as to control the boring means. CONSTITUTION:An ultrasonic probe 2a is abutted to the position of a skull 11 decided to be the penetration passage to reach a focus in the skull, a pulse ultrasonic wave is transmitted and received in the skull 11, and the thickness D of the skull 11 is operated by a CPU 15. And depending on the thickness D, a specific threshold value as to the boring depth is set by a threshold value setting unit 7. Then, a hole 2 is opened by a drill 1 while transmitting an ultrasonic wave from one side ultrasonic probe 2a, in the condition providing a pair of ultrasonic probes 2a and 2b on both sides of the drill 1, and only a received signal in a specific time width as to a surface acoustic wave transmitting in the skull 11 is extracted, the transmitting energy of the extracted surface acoustic wave is integrated, and the drill 1 is controlled according to the different value with the specific threshold value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the depth of perforation when a hole is drilled in any part of the skull when a required part of the skull is cut and the cranial flap is opened to open the craniotomy in a patient's brain surgery. The present invention relates to a skull perforation monitoring device that can be monitored and controlled to improve the safety and reliability of a craniotomy procedure.

[0002]

2. Description of the Related Art In brain surgery on a patient, the most appropriate approach route for reaching a lesion in the skull is determined, the hair of the site is cut, and the scalp is cut open. Either open one hole in the skull, or open several holes and cut between the holes and turn the bone flap to expose the target brain region and apply it to that region. It is common to give surgery. In this case, in order to open the required site, a hole is cut or cut in the skull using an electric drill or a cranial means such as a drill, an electric knife, or an electric saw using compressed air. It is necessary to prevent the perforation of the brain from reaching a depth deeper than the thickness of the skull and reaching a portion called dura covering the brain contents. For this reason, the setting of the rotation torque of the drill, the drilling speed, or the stop position requires careful attention based on the experience of the operator.

[0003]

However, in the craniotomy procedure in the above-mentioned current brain surgery, in order to make a hole in an arbitrary portion of the skull, it is necessary to pay close attention based on the experience of the operator and It required a careful procedure that relied on mastery skill. Further, in a drill using compressed air, there is also one in which the rotation of the drill is automatically stopped by detecting a pressure change when the tip of the drill blade penetrates the skull, but the drill penetrates the skull. Until the last minute, there was almost no change in pressure, and I was forced to rely on the master's skill of the surgeon. Therefore, it takes a long time due to the careful procedure of the operator to make a hole in any part of the skull, and it consumes a lot of time during the operation, and the time for the intracerebral treatment of the core is reduced. There was something to do. Also, no matter how the surgeon exerts mastery skills, it is not always possible to make holes as well, and in some cases the tip of the drill blade may touch the dura mentioned above and cause scratches. In some cases, the safety and certainty of surgery could be impaired.

Therefore, the present invention addresses such problems and improves the safety and reliability of the craniotomy procedure by monitoring and controlling the depth of perforation when a hole is drilled in an arbitrary portion of the skull of a patient. An object of the present invention is to provide a skull perforation monitoring device that can be used.

[0005]

In order to achieve the above-mentioned object, a skull perforation monitoring device according to the present invention comprises a perforation means for perforating an arbitrary portion of the skull and both sides of the perforation means sandwiching the perforation means. A plurality of ultrasonic probes for transmitting and receiving ultrasonic waves in the skull, transmitting means and receiving means for driving the ultrasonic probes to transmit and receive ultrasonic waves, and inside the skull by the transmitted ultrasonic waves Of the surface acoustic wave propagating through the time gate means for extracting only the received signal within a predetermined time width, means for accumulating the propagation energy signal of the surface acoustic wave extracted by the time gate means, and perforation of the skull. Means for setting a predetermined threshold value for the depth, difference amplifying means for comparing the threshold value from the threshold value setting means with the signal of the propagation energy from the integrating means and outputting the difference value, This difference Enter the difference value from the amplifying means those comprising a means for controlling the operation of the drilling means.

[0006]

The skull perforation monitoring device configured as described above is
A plurality of ultrasonic probes arranged on both sides of a perforating means for making a hole in an arbitrary part of the skull transmit and receive ultrasonic waves in the skull, and the ultrasonic probe is transmitted by a transmitting means and a receiving means. The child is driven to transmit / receive ultrasonic waves, and the ultrasonic wave transmitted by the time gate means extracts only the received signal within a predetermined time width of the surface acoustic wave propagating in the skull, and the time gate is made by the integrating means. The signals of the surface energy of the surface acoustic waves extracted by the means are integrated, while the threshold value setting means sets a predetermined threshold value for the puncture depth of the skull, and the difference amplifying means sets the threshold value setting means. Of the propagation energy from the integrating means and outputs the difference value, and the control means of the punching means inputs the difference value from the difference amplifying means to operate the punching means. To By Gosuru operates to drill a hole in any part of the skull by borehole section. This makes it possible to improve the safety and certainty of the craniotomy procedure by monitoring and controlling the depth of perforation when making a hole in any part of the skull.

[0007]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a skull perforation monitoring device according to the present invention. This skull perforation monitoring device monitors and controls the depth of perforation when a hole is drilled in any part of the skull when a required part of the skull is cut and the cranial flap is opened to open the cranial bone in a patient's brain surgery. As shown in the figure, a perforator 1, a pair of ultrasonic probes 2a and 2b, a wave transmitter 3, a wave receiver 4, a time gate circuit 5, an integrator 6, and A threshold value setting device 7, a differential amplifier 8, a power amplifier 9, and a torque / power controller 10 are provided.

The perforator 1 serves as a perforation means for forming a hole in an arbitrary portion of the skull 11 of the patient, and is composed of, for example, an electric drill. The pair of ultrasonic probes 2a and 2b transmits / receives ultrasonic waves to / from the skull 11, is arranged on both sides of the perforator 1 and is in contact with the surface of the skull 11, and is mainly the skull. The surface acoustic wave propagating through 11 is measured. As the pair of ultrasonic probes 2a and 2b, it is desirable to use so-called oblique angle probes in order to efficiently generate and measure surface acoustic waves. The wave transmitter 3 serves as a wave transmitter that drives one ultrasonic probe 2a of the pair of ultrasonic probes 2a and 2b to transmit an ultrasonic wave. Transmission control is performed according to the pulse sequence determined in. Furthermore, the wave receiver 4
Is a receiving means for inputting, amplifying and detecting the ultrasonic signal received by the ultrasonic probe 2a or 2b.

The time gate circuit 5 serves as a gate means for extracting only the received signal within a predetermined time width of the surface acoustic wave propagating in the skull 11 by the ultrasonic wave transmitted by the one ultrasonic probe 2a. It will be. The integrator 6 serves as means for integrating the propagation energy signal of the surface acoustic wave extracted by the time gate circuit 5, and its output signal is sent to the differential amplifier 8 and the A / D converter 13 described later. It is like this. Further, the threshold value setting device 7 serves as means for setting a predetermined threshold value for the depth of perforation when the perforator 1 makes a hole in the skull 11, and the correlation curve shown in FIG. The central processing unit (CPU) 15 is set manually based on the bus line 14 or is automatically set by the central processing unit (CPU) 15. And the differential amplifier 8
Is an input of the threshold value for the depth of perforation output from the threshold value setting device 7 and the signal of the propagation energy of the surface acoustic wave output from the integrator 6, and the difference value is output. The output signal is sent to a power amplifier 9 described later.

The power amplifier 9 inputs the difference value signal output from the differential amplifier 8 and performs power amplification. Further, the torque / power controller 10 receives the power signal output from the power amplifier 9 to generate a torque / power control signal for the punch 1 and sends it to the punch 1. The power amplifier 9 and the torque / power controller 10 constitute a means for controlling the operation of the punch 1 by inputting the difference value signal from the differential amplifier 8.

In FIG. 1, reference numeral 16 is an integrator 6
Shows a memory for storing data obtained by digitizing the output signal of A.D.A. by the A / D converter 13 and sampled by an arithmetic control system by the CPU 15. Reference numeral 17 is an analog signal for inputting data from the CPU 15 or the memory 16. A D / A converter for converting into
7 shows a speaker which inputs a signal output from the device 7 and generates a warning sound indicating that a desired hole has been opened in the skull 11. The first selection switch 19 has two contacts a and b, and whether the reflected energy is used for the surface acoustic waves transmitted and received by the ultrasonic probes 2a and 2b and propagating in the skull 11 (contacts). a) and whether to use the transmitted energy (contact b) is selected. Further, the second selection switch 20 has two contacts c and d, and whether the operation control of the punch 1 is performed by analog processing (contact c) or whether arithmetic control of digital processing by the CPU 15 is used ( The contact point d) is selected.

Next, the operation of the skull perforation monitoring device thus constructed will be described. First, before cutting a required portion of the skull 11, the thickness of the skull 11 at that portion is measured. FIG. 2 is a cross-sectional explanatory view schematically showing the structure of the skull portion from which the scalp has been peeled off, but the skull 11 has a superficial bone plate 11a, an inner bone plate 11b, and a bone marrow 11c sandwiched therebetween. It has a three-layer structure, for example, about 7-8 mm
Has a thickness of. Reference numeral 21 indicates the brain contents wrapped in the dura, and reference numeral 22 indicates the air that is in contact with the superficial bone plate 11a. Then, the above air 22, and the skull 11, the acoustic impedance of the brain contents 21 are each 0.0004kg / m ² /s,3.2~7.4kg/m ² /s,1.56
It is kg / m ² / s, and the skull 11 has the acoustically stiffest structure.

In such a state, the skull 1 determined as the most appropriate entry route for reaching the lesion in the skull 1
As shown in FIG. 2, for example, one ultrasonic probe 2a is brought into contact with the first portion. Then, the ultrasonic probe 2a is controlled by the wave transmitter 3 and the wave receiver 4 shown in FIG. 1 to transmit and receive pulsed ultrasonic waves in the skull 11. At this time, the first selection switch 19 shown in FIG.
Connected to the side. Then, the transmitted pulse ultrasonic wave reaches the inner layer bone plate 11b in the thickness direction in FIG. 2, is reflected by the bottom surface of the inner layer bone plate 11b, and the reflected ultrasonic wave is dependent on the thickness D of the skull 11 for a time. It is delayed and received by the ultrasonic probe 2a. Therefore, the CPU 15 calculates the delay time signal to calculate the skull 1
The thickness D of 1 can be measured. For example, frequency 1
When pulsed ultrasonic waves of MHZ are used, the average longitudinal ultrasonic wave propagation velocity of the skull is 2700 to 4100 m / s, so assuming that the time resolution is 0.1 μs, the thickness D with an accuracy of about 0.1 mm. Can be measured.

Next, when the thickness D of the skull 11 is measured in this way, the threshold setting device 7 sets a predetermined threshold value for the depth of perforation when the skull 11 is bored based on this measurement. Set. For example, when the thickness of the skull 11 is D mm, the threshold value of the depth of perforation is set as (D-0.1) mm.

Next, when the threshold value for the depth of perforation is set as described above, this time the skull 11 is actually cut.
Make a hole in the required area. In FIG. 3, the skull 11 sandwiched between the air 22 and the brain contents 21 has a thickness D = 7.
It can be regarded as an elastic plate of ˜8 mm, and Lamb wave which is one mode of the surface acoustic wave propagates in the elastic plate surface. Therefore, the perforator 1 is positioned at the determined perforation site on the skull 11 as shown in FIG. 3, and a pair of ultrasonic probes 2a and 2b are placed and abutted on both sides of the perforator 1 sandwiched therebetween. . Then, while transmitting ultrasonic waves from one ultrasonic probe 2a, the perforator 1 is driven to open a hole 23 in a required portion of the skull 11.

At this time, when the surface acoustic wave transmitted from one ultrasonic probe 2a propagates inside the skull 11 and reaches the above-mentioned hole 23 on the way, it depends on the perforation amount d accompanying the perforation. Part of the light is reflected at the hole 23, and the other part is transmitted through the bone connecting part. The reflected surface acoustic wave and the transmitted surface acoustic wave are received by the one ultrasonic probe 2a or the other ultrasonic probe 2b, respectively. In this state,
When the first selection switch 19 shown in FIG. 1 is connected to the contact b side and the transmitted surface acoustic wave signal is received by the ultrasonic probe 2b to measure the transmitted energy, drilling progresses and the amount of drilling d
The transmission energy decreases with increasing. Further, the first selection switch 19 is connected to the contact a side,
When the ultrasonic probe 2a receives the signal of the reflected surface acoustic wave and measures the reflected energy, the reflected energy increases as the drilling progresses and the perforation amount d increases.

This is shown in the graph of FIG. 4, the horizontal axis represents the normalized cutting thickness (d / D) obtained by dividing the perforation amount d in FIG. 3 by the thickness D of the skull 11, and the vertical axis represents the reflected energy Ea and the transmitted energy Eb. As is clear from this graph, d / D = 1.0
It is understood that Ea shows a sharp increase and Eb shows a sharp decrease just before the hole 23 penetrates. This phenomenon is considered to be because when the Lamb wave propagates and the remaining thickness (D-d) becomes thinner than the minimum thickness required for the propagation, the propagation thereof is rapidly hindered. Then, the perforation process of the skull 11 can be indirectly monitored by measuring the change in the energy amount of the reflected energy Ea or the transmitted energy Eb of the surface acoustic wave immediately before the penetration of the hole.

In this case, the propagation of the surface acoustic wave is preferably such that the thickness of the propagation member is about one wavelength of the surface acoustic wave, and in the skull 11, about 500 KHz to 3 kHz.
MHz is preferred. Also, the time from transmission to reception is
It is determined by the propagation velocity when the skull 11 is regarded as an elastic plate. When the received signal delayed by this propagation time from the time of transmission is time-gated by the time gate circuit 5 shown in FIG. 1, the obtained signal is a direct propagation wave propagating the shortest distance between the ultrasonic probes 2a and 2b. Ultrasonic waves that have been considered and have passed through multiple reflection signals or other paths are rejected by the time gate circuit 5. It should be noted that the correlation curve between the normalized cutting thickness (d / D) and the reflected energy Ea or the transmitted energy Eb as shown in FIG. 4 for a specific frequency may be obtained in advance by animal experiments or calculations. .

The signal of the reflected energy Ea or the transmitted energy Eb measured as described above is sent to the differential amplifier 8 after being integrated by the integrator 6. The threshold value for the drilling depth set by the threshold value setting device 7 is inputted to the differential amplifier 8, and the differential amplifier 8 receives the reflected energy Ea or the transmitted energy. The Eb signal is compared with the threshold value and the difference value is output. Next, the output signal of the difference value is sent to the power amplifier 9 through the second selection switch 20 connected to the contact c side, and is power-amplified. Thereafter, the power-amplified signal is sent to the torque / power controller 10 to generate a torque / power control signal for the punch 1. The torque / power control signal output from the torque / power controller 10 is input to the perforator 1 to control the power and rotational torque of the perforator 1.

At this time, the torque / power control signal is
It is controlled by the magnitude of the difference value signal from the differential amplifier 8 and is reduced in proportion to the remaining amount (D−d) of the thickness D of the skull 11 represented by the difference value signal (see FIG. 3). Has been done. Therefore, the skull 1 by the perforator 1
The depth of drilling for 1 becomes large, and the residual amount (D-
As d) becomes smaller, the power and rotation torque of the perforator 1 are reduced, and the perforator 1 is automatically stopped immediately before the hole 23 of the skull 11 penetrates (for example, D−d = 0.1 mm). As a result, it is possible to form a hole in the skull 11 in a safe and reliable manner without depending on the skill and skill of the operator as in the conventional case.

In FIG. 1, when the second selection switch 20 is connected to the contact d side, the output signal output from the integrator 6 and converted into a digital signal by the A / D converter 13 is a bus signal. It is sent to the CPU 15 via the line 14 and is sampled and stored in the memory 16. Also, the above C
The PU 15 controls the threshold value setting device 7 to set a threshold value for the depth of perforation, executes various calculation / comparison / amplification processes, and outputs the result to the D / A converter 17
Is converted into an analog signal and supplied to the power amplifier 9.
The subsequent operation is similar to that described above. Furthermore, the above D / A
The output signal from the converter 17 is also supplied to the speaker 18, and a warning sound is generated when the hole 23 is drilled to a predetermined depth in the hole drilling shown in FIG.

FIG. 5 is a plan view showing another embodiment of the drilling operation for the skull 11. This embodiment shows a case where a plurality of holes 23, 23, ... Are drilled in a certain region of the skull 11, for example, four punches 1a, 1b ,.
1c and 1d are arranged so as to form a quadrangle, the first ultrasonic probe 2a is arranged at the center of the quadrangle, and the second to the fifth are sandwiched by the perforators 1a to 1d. The ultrasonic probes 2b, 2c, 2d and 2e are arranged. The actual individual drilling work is the same as that of the above-described embodiment described with reference to FIGS. When the reflected energy is measured by using the first ultrasonic probe 2a arranged in the center of the quadrangle as a reflection type, even if only one of the first ultrasonic probe 2a is provided around it. It is possible to control the four punches 1a to 1d.

[0023]

Since the present invention is constructed as described above,
When cutting a required part of the skull in a patient's brain surgery and reversing the bone flap to open the craniotomy, monitor and control the depth of perforation when making a hole in any part of the skull to ensure the safety of the craniotomy procedure. The certainty can be improved. Therefore, without relying on the skill of the surgeon as in the past,
Even a surgeon of ordinary skill can safely and reliably perform a drilling operation on the skull. Further, it is possible to take much time for intracerebral intracerebral treatment without requiring a long time for drilling the skull, unlike the conventional case. From these, the safety and certainty of the brain surgery of the patient can be improved as a whole.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a skull perforation monitoring device according to the present invention.

FIG. 2 is a cross-sectional explanatory diagram that schematically shows the structure of the skull portion from which the scalp has been peeled off, and is an explanatory diagram of a state in which the thickness of the skull is measured in the present invention.

FIG. 3 is a cross-sectional view for explaining an operation of actually making a hole in a required portion of the skull.

FIG. 4 is a graph showing the relationship between the normalized cutting thickness and the reflected energy and transmitted energy in the drilling operation for the skull.

FIG. 5 is an explanatory plan view showing another embodiment of the drilling operation for the skull.

[Explanation of symbols]

 1, 1a to 1d ... Punch 2a to 2e ... Ultrasonic probe 3 ... Wave transmitter 4 ... Wave receiver 5 ... Time gate circuit 6 ... Integrator 7 ... Threshold value setter 8 ... Differential amplifier 9 ... Power amplifier 10 ... Torque / power controller 11 ... Skull 15 ... CPU 19 ... First selection switch 20 ... Second selection switch 23 ... Hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masamichi Tomonaga 3-15-19 Sasaoka, Chuo-ku, Fukuoka-shi, Fukuoka

Claims (1)

[Claims] 1. A piercing means for piercing an arbitrary portion of a skull, a plurality of ultrasonic probes arranged on both sides of the piercing means for transmitting and receiving ultrasonic waves in the skull, and the ultrasonic probe. Transmitting means and receiving means for driving a tentacle to transmit and receive ultrasonic waves, and a time gate for extracting only received signals within a predetermined time width of the surface acoustic wave propagating in the skull by the transmitted ultrasonic waves. Means, means for accumulating signals of propagation energy of surface acoustic waves extracted by the time gate means, means for setting a predetermined threshold value for the perforation depth of the skull, and this threshold value setting means Difference threshold value and a signal of the propagation energy from the integrating means and outputs the difference value, and a means for controlling the operation of the perforating means by inputting the difference value from the difference amplifying means. Prepared with A skull perforation monitoring device characterized in that