Ultrasonic skull cutting device and method of cutting

Abstract

The application provides an ultrasonic skull cutting device and a cutting method, the ultrasonic skull cutting device comprises a button assembly, a driving assembly, a cutting assembly and a shell, the button assembly is located above the driving assembly, the button assembly and the driving assembly are arranged in the shell, and a cutting saw of the cutting assembly is connected with a variable amplitude shaft of the driving assembly; based on the ultrasonic vibration principle, the cutting saw connected with the variable amplitude shaft generates high-frequency mechanical vibration through an ultrasonic transducer, the cutting saw mode is periodically changed with the periodic change frequency of the ultrasonic transducer, the cutting saw can effectively avoid being stuck during cutting the skull, unnecessary surgical risks are reduced, the gap between the skulls is smaller, the skull healing quality is improved, the skull healing time is shortened, and the relative position state of the cutting saw and the skull can be intelligently judged by detecting the real-time working current of the driving motor of the cutting saw, and the skull cutting efficiency is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, to a surgical cutting device using ultrasound, and particularly to an ultrasonic cranial cutting device and its cutting method. Background Technology

[0002] Craniotomy is a surgical procedure that involves cutting open the skull to treat brain tissue. The general steps are as follows: 1. Cutting open the scalp; 2. Drilling 3-4 round holes in the skull; 3. Cutting the skull along the holes; 4. Cutting open the dura mater; 5. Performing surgery on the brain; 6. Suturing and fixing the dura mater, skull, and scalp in sequence.

[0003] Currently, craniotomy typically lasts 2-8 hours or more, with a significant portion spent opening the skull. In existing techniques, surgeons often need to hold a craniotomy saw and cut along pre-drilled holes to remove the skull. However, in practice, prolonged holding, especially the saw's tendency to jam, easily leads to operator fatigue. Increased physical exertion can cause instability in the saw during cutting, slowing down the surgery and potentially causing safety issues such as jamming or chipping. Furthermore, it increases the gap between the skull bones after the craniotomy, the size of which directly affects whether the bone can heal completely. If the gap is small and there is no soft tissue filling it, the skull can heal completely.

[0004] Therefore, it is necessary to design a craniotomy saw that prevents the saw teeth from getting stuck, reduces the interskeletal gap during craniotomy, effectively avoids unnecessary surgical risks, improves the quality of cranial healing, and shortens the time of cranial healing. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an ultrasonic skull cutting device and method. Based on the principle of ultrasonic vibration, the ultrasonic transducer causes the cutting saw connected to the amplitude transformer to generate high-frequency mechanical vibration, which can effectively prevent the cutting saw from jamming when cutting the skull, reducing unnecessary surgical risks. At the same time, it makes the gap between skull bones smaller, improves the quality of skull healing, and shortens the skull healing time. Furthermore, by detecting the real-time operating current of the drive motor when the cutting saw is working, the relative position of the cutting saw and the skull can be cleverly determined, which effectively improves the quality of skull cutting and increases cutting efficiency.

[0006] This invention provides an ultrasonic craniotomy device, comprising a button assembly, a drive assembly, a cutting assembly, and a housing. The button assembly is located above the drive assembly, and both the button assembly and the drive assembly are disposed within the housing. The button assembly includes a button, a sliding seat, a return spring, a guide post, a protrusion, a slot, and a main controller. The first end of the button passes through the sliding seat and is slidably connected to it. The guide post is disposed within the sliding seat, which is fixedly installed within the housing. The return spring is fitted onto the guide post, with its first end connected to the sliding seat. The second end of the return spring passes through the U-shaped groove of the button, which has an arc-shaped design. The protrusion is disposed on the side of the button and engages with the slot. The main controller is disposed on one side of the sliding seat. The drive assembly includes a drive motor, a flange, a planetary reducer, a rotating shaft, a first pulley, a synchronous belt, a second pulley, an amplitude transformer shaft, an angular contact bearing, and an ultrasonic transducer. The system comprises an ultrasonic transducer, an annular carbon brush, a spring, and a locking nut. The output shaft of the drive motor is connected to the input end of the planetary reducer via a flange. The output end of the planetary reducer is connected to the rotating shaft. The first pulley is fixedly connected to the rotating shaft via a key. The first pulley meshes with the second pulley via a synchronous belt. The second pulley is mounted on the amplitude-changing shaft. The middle part of the amplitude-changing shaft is rotatably connected to the housing via an angular contact bearing. The ultrasonic transducer is fixedly installed at the first end of the amplitude-changing shaft. A conductive slip ring is provided at the bottom of the ultrasonic transducer. The annular carbon brush is clamped to the conductive slip ring via the spring. The two ends of the spring are respectively connected to the annular carbon brush and the inner surface of the housing. The cutting assembly includes a cutting saw, a connecting flange, and an outer cover. The connecting flange is located at the second end of the amplitude-changing shaft. The cutting saw is connected to the amplitude-changing shaft via the connecting flange. The cutting saw mode changes periodically with the periodic frequency of the ultrasonic transducer. The outer cover is fixedly installed on the outside of the connecting flange.

[0007] Preferably, the ultrasonic transducer is connected to the amplitude transformer shaft via a double-ended stud, the double-ended stud having the opposite rotation direction to the locking nut, the locking nut being located between the ultrasonic transducer and the angular contact bearing, and the locking nut being threadedly connected to the amplitude transformer shaft to position the angular contact bearing axially.

[0008] Preferably, the housing includes a positioning post, a guide seat, and a limiting block, with the positioning post inserted into the guide seat and the angular contact bearing positioned and fixed by the limiting block.

[0009] Preferably, the end of the amplitude-changing shaft near the cutting saw is rotatably connected to the housing via a deep groove ball bearing.

[0010] Preferably, the second end of the amplitude-changing shaft has a rectangular structure to circumferentially position the connecting flange.

[0011] Preferably, the main controller is connected to the drive motor via a wire. The main controller is equipped with a position sensor that can monitor the deformation of the return spring in real time, convert the deformation of the return spring into an electrical signal, and send commands to control the drive motor. With the cooperation of the components in the drive assembly, the cutting saw can cut the skull.

[0012] In a second aspect of the present invention, a cutting method using the aforementioned ultrasonic cranial cutting device is provided, comprising the following steps:

[0013] S1. When cutting the skull, bring the cutting saw of the cutting assembly close to the skull cutting point, press the button, and as the button slides in the slide seat, the return spring is compressed. The position sensor in the main controller converts the deformation of the return spring into an electrical signal and sends a command to the drive motor.

[0014] S2. The drive motor drives the rotating shaft to rotate through a planetary reducer, which in turn drives the first pulley mounted on the rotating shaft to rotate. The first pulley drives the second pulley to rotate through a synchronous belt, and the amplitude shaft fixedly connected to the second pulley rotates.

[0015] S3. The ultrasonic transducer at the first end of the amplitude shaft, through the cooperation of the annular carbon brush and the conductive slip ring, causes the cutting saw at the second end of the amplitude shaft to generate high-frequency vibration. The cutting saw mode changes periodically with the periodic frequency change of the ultrasonic transducer, which can effectively prevent the cutting saw from jamming when cutting the skull.

[0016] S4. Set a current parameter and mark it as the saw penetration current. When the real-time current suddenly drops from the normal working current range at a certain moment during the continuous feeding and cutting of the cutting saw, the current drop inflection point is identified as the penetration point of the skull.

[0017] S5. When the current drop inflection point occurs, that is, when the skull penetration point occurs, the current supply to the drive motor is cut off. After the machine stops completely, the drive assembly drives the cutting saw back to the initial position.

[0018] S6. After returning to the initial position, rotate the cutting saw by an angle to the position above the next skull cutting point, and repeat the above operation to complete the cutting of the entire skull.

[0019] In a preferred embodiment, the vibration frequency expression of the cutting saw is:

[0020]

[0021] In the formula, K R —Mode shape coefficient; D—Outer diameter of the cutting saw; E—Elastic modulus of the cutting saw material; δ—Matrix thickness; g—Acceleration due to gravity; λ—Poisson's ratio; ρ—Material density;

[0022] Among them, the mode shape coefficient K of the cutting saw R The expression that conforms to the following:

[0023] K R =2.9979 / (1-d / D) 2.188

[0024] In the formula, d is the diameter of the shaft hole of the cutting saw.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The ultrasonic skull cutting device of the present invention is based on the principle of ultrasonic vibration. The drive motor in the drive assembly drives the amplitude shaft to rotate through the reducer. The amplitude shaft is also equipped with an ultrasonic transducer, which causes the cutting saw connected to the amplitude shaft to generate high-frequency mechanical vibration. The cutting saw mode changes periodically with the periodic frequency change of the ultrasonic transducer, which can effectively avoid the cutting saw from jamming when cutting the skull, and at the same time make the gap between skulls smaller.

[0027] 2. In the ultrasonic cranial cutting device of the present invention, the annular carbon brush is clamped to the conductive slip ring of the ultrasonic transducer by a spring, and the ultrasonic transducer is connected to the amplitude transformer shaft by a double-ended stud to ensure that the ultrasonic transducer is always energized during rotation. The ultrasonic transducer is always connected to high-frequency electrical energy, thereby generating high-frequency mechanical vibration.

[0028] 3. The ultrasonic skull cutting device of the present invention determines the current state of the cutting saw by detecting the real-time operating current of the drive motor of the cutting saw, whether it has contacted the skull to complete the blade setting or whether it has cut through the skull to complete the cutting at the current point, and determines the relative position of the cutting saw and the skull, thereby improving the quality of skull cutting and improving cutting efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the ultrasonic craniotomy device of the present invention;

[0030] Figure 2 This is a front view schematic diagram of the overall structure of the ultrasonic craniotomy device of the present invention;

[0031] Figure 3 This is a top view schematic diagram of the overall structure of the ultrasonic craniotomy device of the present invention;

[0032] Figure 4This is a schematic diagram of the button assembly in this invention;

[0033] Figure 5 This is a schematic diagram of the button assembly in this invention, showing the interaction between the button and the reset spring.

[0034] Figure 6 This is a schematic diagram of the cutting component in this invention;

[0035] Figure 7 This is a schematic diagram of the n1-order modal principal vibration mode of the cutting saw in this invention;

[0036] Figure 8 This is a schematic diagram of the n2-order modal principal vibration mode of the cutting saw in this invention;

[0037] Figure 9 This is a schematic diagram of the n3rd order modal principal vibration mode of the cutting saw in this invention;

[0038] Figure 10 This is a schematic diagram of the n4th order modal principal vibration mode of the cutting saw in this invention.

[0039] Key reference numerals:

[0040] Button assembly 1, button 11, slide seat 12, return spring 13, guide post 14, protrusion 15, slot 16, main controller 17, drive assembly 2, drive motor 201, flange 202, planetary reducer 203, rotating shaft 204, first pulley 205, synchronous belt 206, second pulley 207, amplitude shaft 208, angular contact bearing 209, ultrasonic transducer 210, annular carbon brush 211, spring 212, locking nut 213, cutting assembly 3, cutting saw 31, connecting flange 32, outer cover 33, outer shell 4, positioning post 41, guide seat 42, limit block 43. Detailed Implementation

[0041] To fully describe the technical content, structural features, objectives, and effects of this invention, a detailed description will be provided below in conjunction with the accompanying drawings.

[0042] This invention relates to an ultrasonic craniotomy device, which is a surgical cutting device that utilizes ultrasound, such as... Figures 1-3As shown, it includes a button assembly 1, a drive assembly 2, a cutting assembly 3, and a housing 4. The button assembly 1 is located above the drive assembly 2. The button assembly 1 and the drive assembly 2 are housed inside the housing 4. The cutting saw 31 of the cutting assembly 3 is connected to the amplitude transformer shaft 208 of the drive assembly 2. The drive assembly 2 includes a drive motor 201, a flange 202, a planetary reducer 203, a rotating shaft 204, a first pulley 205, a synchronous belt 206, a second pulley 207, an amplitude transformer shaft 208, an angular contact bearing 209, an ultrasonic transducer 210, an annular carbon brush 211, a spring 212, and a locking nut 213. The output shaft of the drive motor 201 is connected to the input end of the planetary reducer 203 through the flange 202. The output end of the planetary reducer 203 is connected to the rotating shaft 204. The first pulley 205 is fixedly connected to the rotating shaft 204 by a key. The first pulley 205 is connected to the second pulley 207 through the synchronous belt 206. The second pulley 207 is mounted on the amplitude shaft 208. The middle part of the amplitude shaft 208 is rotatably connected to the housing 4 through the angular contact bearing 209. The ultrasonic transducer 210 is fixedly installed at the first end of the amplitude shaft 208. The bottom of the ultrasonic transducer 210 is provided with a conductive slip ring. The annular carbon brush 211 is clamped to the conductive slip ring through the spring 212. The two ends of the spring 212 are respectively connected to the annular carbon brush 211 and the inner surface of the housing 4. The ultrasonic transducer 210 is connected to the amplitude shaft 208 through a double-ended stud. The double-ended stud and the locking nut 213 have opposite rotation directions. The locking nut 213 is located between the ultrasonic transducer 210 and the angular contact bearing 209. The locking nut 213 is threadedly connected to the amplitude shaft 208 to position the angular contact bearing 209 axially. The end of the amplitude shaft 208 near the cutting saw 31 is rotatably connected to the housing 4 through a deep groove ball bearing. The outer casing 4 includes a positioning post 41, a guide seat 42, and a limiting block 43. The positioning post 41 is inserted into the guide seat 42, and the angular contact bearing 209 is positioned and fixed by the limiting block 43.

[0043] like Figure 4 and Figure 5As shown, the button assembly 1 includes a button 11, a slide seat 12, a return spring 13, a guide post 14, a protrusion 15, a slot 16, and a main controller 17. The first end of the button 11 passes through the slide seat 12 and the two are slidably connected. The guide post 14 is disposed in the slide seat 12, and the slide seat 12 is fixedly installed in the housing 4. The return spring 13 is fitted on the guide post 14, and the first end of the return spring 13 is connected to the slide seat 12. The second end of the return spring 13 passes through the U-shaped groove of the button 12. The second end of the button 11 has an arc surface design. The protrusion 15 is disposed on the side of the button 12 and is engaged with the slot 16. The main controller 17 is disposed on one side of the slide seat 12. The main controller 17 is connected to the drive motor 201 via wires. The main controller 17 is equipped with a position sensor, which can monitor the deformation of the return spring 13 in real time, convert the deformation of the return spring 13 into an electrical signal, and send commands to control the drive motor 201. With the cooperation of the components in the drive assembly 2, the cutting saw 31 cuts the skull.

[0044] like Figure 6 As shown, the cutting assembly 3 includes a cutting saw 31, a connecting flange 32, and an outer cover 33. The connecting flange 32 is located at the second end of the amplitude shaft 208. The second end of the amplitude shaft 208 has a rectangular structure, which circumferentially positions the connecting flange 32. The cutting saw 31 is connected to the amplitude shaft 208 through the connecting flange 32. The mode of the cutting saw 31 changes periodically with the periodic frequency change of the ultrasonic transducer 210. The outer cover 33 is fixedly installed on the outside of the connecting flange 32.

[0045] The cutting method of the ultrasonic cranial cutting device of the present invention includes the following steps:

[0046] S1. When cutting the skull, bring the cutting saw 31 of the cutting assembly 3 close to the skull cutting point and press the button 11. As the button 11 slides in the slide seat 12, the return spring 13 is compressed. The position sensor in the main controller 17 converts the deformation of the return spring 13 into an electrical signal and sends a command to the drive motor 201.

[0047] S2. Drive motor 201 drives rotating shaft 204 to rotate through planetary reducer 203, which drives first pulley 205 mounted on rotating shaft 204 to rotate. First pulley 205 drives second pulley 207 to rotate through synchronous belt 206. Amplitude shaft 208 fixedly connected to second pulley 207 rotates.

[0048] S3. The ultrasonic transducer 210 at the first end of the amplitude shaft 208, through the cooperation of the annular carbon brush 211 and the conductive slip ring, causes the cutting saw 31 at the second end of the amplitude shaft 208 to generate high-frequency vibration. The mode of the cutting saw 31 changes periodically with the periodic frequency of the ultrasonic transducer 210, which can effectively prevent the cutting saw 31 from jamming when cutting the skull.

[0049] S4. Set a current parameter and mark it as the sawing current. When the real-time current suddenly drops from the normal working current range at a certain moment during continuous feeding and cutting of the cutting saw 31, the inflection point of the current drop is identified as the point of skull penetration.

[0050] S5. When the current drop inflection point occurs, that is, when the skull penetration point occurs, the current supply to the drive motor 201 is cut off. After the machine stops completely, the drive assembly 2 drives the cutting saw 31 back to the initial position.

[0051] S6. After returning to the initial position, rotate the cutting saw 31 by an angle to the position above the next skull cutting point, and repeat the above operation to finally complete the cutting of the entire skull.

[0052] The ultrasonic cranial cutting device and cutting method of the present invention will be further described below with reference to embodiments:

[0053] like Figures 1-6 As shown, the operator holds the handle on the outer casing 4 and controls the drive motor 201 via button 11. The motor outputs power to the rotating shaft 204 via the planetary reducer 203. The first pulley 205 mounted on the rotating shaft 204 rotates, driving the second pulley 207 to rotate via the synchronous belt 206. The ultrasonic transducer 210 is connected to the amplitude transformer shaft 208 via a double-ended stud, and the double-ended stud and the locking nut 213 rotate in opposite directions to ensure a stable connection. The ultrasonic transducer 210 rotates with the amplitude transformer shaft 208. The ultrasonic transducer 210 is equipped with a conductive slip ring. The arrangement of the annular carbon brush 211 and the conductive slip ring ensures that the ultrasonic transducer 210 remains energized while rotating. The ultrasonic transducer 210 is always connected to high-frequency electrical energy, generating high-frequency mechanical vibration. The amplitude-changing shaft 208 is a half-wavelength amplitude-changing shaft, and its node is located at the mounting position of the angular contact bearing 209. The high-frequency vibration generated by the ultrasonic transducer 210 gradually amplifies the amplitude of the mechanical vibration under the action of the amplitude-changing shaft 208, generating multiple micrometer-level axial high-frequency vibrations at the second end of the amplitude-changing shaft 208. Under the action of high-frequency vibration, it can effectively prevent the cutting saw 31 from jamming when cutting the skull, thereby reducing friction and allowing the cutting saw 31 to be made thinner. It also makes the cutting process more stable, effectively avoiding unnecessary surgical risks, while making the gaps between skull bones smaller, improving the quality of skull healing, and shortening the skull healing time.

[0054] like Figures 7-10As shown, the vibration of the cutting saw 31 is a deviation from its equilibrium position, oscillating back and forth around the equilibrium position as its midplane. This vibration is usually caused by external excitation forces and is considered forced vibration. Most of the vibrations of the cutting saw 31 are the sum of multiple individual vibration modes, each including a specific vibration mode and a vibration at a specific frequency. The vibration frequency of each mode is called its natural frequency. When the frequency of the external excitation force is the same as the natural frequency, the cutting saw 31 operates at that natural frequency. When the frequency of the external excitation force changes periodically between different natural frequencies, the mode shape of the cutting saw 31 also changes periodically.

[0055] The cutting saw 31 is subjected to forced vibration. Analysis determined its vibration frequency to be:

[0056]

[0057] Where: K R —Modal coefficient; D—Outer diameter of the cutting saw; E—Elastic modulus of the cutting saw material; δ—Matrix thickness; g—Acceleration due to gravity; μ—Poisson's ratio; π—Material density.

[0058] The size and mode shape of the cutting saw 31 determine the mode shape coefficient K. R The specific values ​​were obtained through finite element simulation combined with dynamic calculations, where the mode shape coefficient conforms to the following expression:

[0059] K R =2.9979 / (1-d / D) 2.188

[0060] Where: d—diameter of the shaft hole of the cutting saw.

[0061] Through Ansys modal simulation, the required natural frequencies and mode shapes of the cutting saw 31 were obtained. The n1 natural frequency is 546.67Hz, the n2 natural frequency is 954.92Hz, the n3 natural frequency is 1460Hz, and the n4 natural frequency is 2057.6Hz. When the external excitation frequency of the amplitude shaft 208 changes periodically between the natural frequencies, the cutting saw 31 also changes periodically between the mode shapes. During cutting, the centrifugal stress provides strength to the cutting saw 31. The small deformation around the cutting saw 31 can effectively reduce the friction between the skull gap and the cutting saw 31 during cutting, avoid jamming during the cutting process, and improve the efficiency of skull cutting.

[0062] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An ultrasonic craniotomy device, characterized in that, It includes a button assembly, a drive assembly, a cutting assembly, and a housing. The button assembly is located above the drive assembly, and both the button assembly and the drive assembly are disposed within the housing. The button assembly includes a button, a slide seat, a return spring, a guide post, a protrusion, a slot, and a main controller. The first end of the button passes through the slide seat and is slidably connected to it. The guide post is disposed within the slide seat, which is fixedly installed within the housing. The return spring is fitted onto the guide post, with its first end connected to the slide seat. The second end of the return spring passes through the U-shaped groove of the button, which has an arc-shaped design. The protrusion is disposed on the side of the button and engages with the slot. The main controller is disposed on one side of the slide seat. The drive assembly includes a drive motor, a flange, a planetary reducer, a rotating shaft, a first pulley, a synchronous belt, a second pulley, an amplitude transformer shaft, an angular contact bearing, an ultrasonic transducer, an annular carbon brush, a spring, and a locking nut. The output shaft of the drive motor is connected to the input end of the planetary reducer via the flange. The output end of the planetary reducer is connected to the rotating shaft. The first pulley is fixedly connected to the rotating shaft via a key. The first pulley meshes with the second pulley via the synchronous belt. The second pulley is mounted on the amplitude transformer shaft. The middle part of the amplitude transformer shaft is rotatably connected to the housing via an angular contact bearing. The ultrasonic transducer is fixedly installed at the first end of the amplitude transformer shaft. A conductive slip ring is provided at the bottom of the ultrasonic transducer. The annular carbon brush is clamped to the conductive slip ring via the spring. The two ends of the spring are respectively connected to the annular carbon brush and the inner surface of the housing. The cutting assembly includes a cutting saw, a connecting flange, and an outer cover. The connecting flange is located at the second end of the amplitude transformer shaft. The cutting saw is connected to the amplitude transformer shaft through the connecting flange. The cutting saw mode changes periodically with the periodic frequency change of the ultrasonic transducer. The outer cover is fixedly installed on the outside of the connecting flange.

2. The ultrasonic craniotomy device according to claim 1, characterized in that, The ultrasonic transducer is connected to the amplitude transformer shaft via a double-ended stud. The double-ended stud and the locking nut have opposite directions of rotation. The locking nut is located between the ultrasonic transducer and the angular contact bearing. The locking nut is threadedly connected to the amplitude transformer shaft to position the angular contact bearing axially.

3. The ultrasonic craniotomy device according to claim 1, characterized in that, The housing includes a positioning post, a guide seat, and a limiting block. The positioning post is inserted into the guide seat, and the angular contact bearing is positioned and fixed by the limiting block.

4. The ultrasonic craniotomy device according to claim 1, characterized in that, The end of the amplitude-changing shaft near the cutting saw is rotatably connected to the housing via a deep groove ball bearing.

5. The ultrasonic craniotomy device according to claim 4, characterized in that, The second end of the amplitude-changing shaft has a rectangular structure, which is used for circumferential positioning of the connecting flange.

6. The ultrasonic craniotomy device according to claim 1, characterized in that, The main controller is connected to the drive motor via wires. The main controller is equipped with a position sensor that can monitor the deformation of the return spring in real time and convert the deformation of the return spring into an electrical signal. The main controller sends commands to control the drive motor. With the cooperation of the components in the drive assembly, the cutting saw cuts the skull.

7. The ultrasonic craniotomy device according to any one of claims 1-6, characterized in that, Under the continuous feeding and cutting of the cutting saw, when the real-time current suddenly drops from the normal working current range at a certain moment, the inflection point of the current drop is identified as the point of skull penetration. When the current drops to an inflection point, the current supply to the drive motor is cut off.

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