Ultrasonic osteotome for joint surgery

Abstract

The ultrasonic osteotome for the joint surgery is characterized in that the ultrasonic osteotome comprises a piezoelectric transducer (1), an amplitude-change pole (2) and a tool bit (3), the amplitude-change pole (2) is arranged at the front end of the piezoelectric transducer (1), and the tool bit (3) is arranged at the front end of the amplitude-change pole (2); the tool bit (3) comprises a large-end cylinder (31), a transition R angle (32), a small-end cylinder (33) and a cutting part (34); the width of the cutting part (34) is 4-5 mm, the thickness of the cutting part (34) is 2-3 mm, an oval receding groove (341) is formed in the middle of the cutting part, sawteeth (342) are arranged on the two side walls in the axis direction, and the number of the sawteeth on one side is 20-25. The utility model has the advantages of simple design, low processing cost, large amplitude, high safety and the like, and is very suitable for ultrasonic osteotome for joint surgery.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic bone scalpel technology, and more particularly to an ultrasonic bone scalpel for joint surgery. Background Technology

[0002] Bone cutting is a routine clinical procedure commonly used in surgeries such as orthopedic surgery, trauma orthopedics, joint surgery, spinal surgery, dentistry, and neurosurgery. Bone cutting is a typical subtractive manufacturing process, essentially involving clinicians using various medical instruments, such as mechanical devices or those with special energy fields, to remove, reshape, and reconstruct human bone material, thereby achieving surgical treatment.

[0003] Conventional bone material processing methods include drilling, milling, grinding, and sawing. Ultrasonic bone scalpels offer significant advantages over traditional methods, effectively reducing cutting force and temperature. They also provide hemostasis, minimize vibrations around the bone, enhance safety, and shorten postoperative healing time. An ultrasonic bone scalpel system primarily consists of an ultrasonic generator, transducer, amplitude transformer, and cutter head. High-frequency alternating current generated by the ultrasonic generator is applied to the piezoelectric transducer. The vibrations (mechanical waves) generated by the transducer are transmitted through the amplitude transformer to the cutter head, which then contacts the tissue, cutting it through mechanical impact.

[0004] Currently, ultrasonic bone scalpels are mainly used in dentistry. Patent document 1 (application number CN2017205665528) discloses an ultrasonic bone scalpel working tip for posterior alveolar bone cutting, including a working tip connecting part threaded to the ultrasonic bone scalpel, and a working tip neck, a working tip head, and a working tip working part that are sequentially fixedly connected to the working tip connecting part in the same plane. It can extend into the oral cavity, facilitating operation on the posterior tooth area during posterior alveolar bone cutting surgery. Patent document 2 (application number CN2007200805468) discloses an ultrasonic bone scalpel for ultrasonic cutting, comprising a bone scalpel connecting part connected to the ultrasonic bone scalpel handle, a bone scalpel neck integrated with the bone scalpel connecting part, and a bone scalpel head. The bone scalpel neck and the bone scalpel connecting part are coaxially connected, or after the bone scalpel neck and the bone scalpel connecting part are coaxially connected, the lower part of the bone scalpel neck is obliquely offset to one side from the axis, and the upper part of the bone scalpel neck is bent back to the axis. The tail end of the bone scalpel head is connected to the upper part of the bone scalpel neck and then tilted upward to the other side. The bone scalpel head is equipped with various types of blades. The internal thread of the bone scalpel connecting part is connected to the ultrasonic bone scalpel handle, and the cooling water hole at the bottom of the internal thread leads to the bone scalpel neck. A square wrench position is provided in the bone scalpel connecting part. This utility model uses high-frequency ultrasound as a vibration source for precise treatment and reshaping of oral teeth. However, the ultrasonic bone scalpel used in the above patent document is both short and thick, and cannot be used through the minimally invasive arthroscopic channel. With the increasing prevalence of minimally invasive joint surgery, there is an urgent need for a convenient, efficient, and safe endoscopic ultrasonic bone scalpel that can be used through a minimally invasive arthroscopic channel. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides a high-amplitude, high-safety ultrasonic bone scalpel. By designing a high amplitude ratio and a serrated structure in the scalpel head, it features simple design, low processing cost, large amplitude, and high safety, thus overcoming the drawbacks of existing technologies.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An ultrasonic bone scalpel for joint surgery, characterized in that it includes a piezoelectric transducer, an amplitude transformer, and a blade head, wherein the amplitude transformer is disposed at the front end of the piezoelectric transducer, and the blade head is disposed at the front end of the amplitude transformer.

[0008] The length of the cutter head is L1 = N1·λ / 4, where N1 is a positive integer and λ is the wavelength of the sound. It includes a large-end cylinder, a transition R angle, a small-end cylinder, and a cutting part. The length of the large-end cylinder is l1 = 0.1·L1, the length of the small-end cylinder is l2 = 0.6·L1, and the transition R angle is R = 0.5·1 / α·L1. Where the diameter ratio of the large and small end cylinders is α = D1 / D2 = 4~5, D1 and D2 are the diameters of the large and small end cylinders, respectively, and D1 = 20~25mm.

[0009] The width of the cutting part is 4-5mm and the thickness is 2-3mm. The middle of the cutting part has an elliptical clearance groove, and both side walls along the axial direction are equipped with serrations, with 20-25 serrations on each side.

[0010] The length of the piezoelectric transducer is L2 = N2·λ / 2, where N2 is a positive integer, λ is the acoustic wavelength, and its diameter is 20-25 mm.

[0011] The amplitude transformer is cylindrical, with a length L1 = N1 * λ / 4, where N1 is a positive integer, λ is the sound wavelength, and its diameter is 20-25 mm.

[0012] As a preferred embodiment, the ultrasonic bone scalpel further includes a hollow tube, which extends from the bolt of the piezoelectric transducer along the axial direction to the small end cylinder of the scalpel head, and the diameter of the tube is 2-3 mm.

[0013] As a preferred embodiment, the piezoelectric transducer includes bolts, a rear cover plate, a conductive sheet, a piezoelectric ceramic sheet, and a front cover plate. The rear cover plate is located at the rear end of the piezoelectric transducer, and a bolt is disposed at the rear end of the rear cover plate. The front cover plate is located at the front end of the piezoelectric transducer. The conductive sheet and the piezoelectric ceramic sheet are disposed between the rear cover plate and the front cover plate, and the rear cover plate, the conductive sheet, the piezoelectric ceramic sheet, and the front cover plate are connected together by bolts. Preferably, the number of piezoelectric ceramic sheets is four.

[0014] As a preferred embodiment, the amplitude transformer is connected to the piezoelectric transducer by a thread, and the cutter head is connected to the amplitude transformer by a thread.

[0015] As a preferred embodiment, the bolt is made of TC4, the rear cover is made of 90WNiFe, the conductive sheet is made of pure copper, and the front cover is made of TC4.

[0016] As a preferred embodiment, both the amplitude transformer and the cutter head are made of 440A stainless steel.

[0017] As a preferred embodiment, the ultrasonic bone scalpel operates at a frequency of 25–35 kHz.

[0018] As a preferred embodiment, the length of the ultrasonic bone scalpel is any one of 230mm, 345mm, and 460mm.

[0019] The front and back ends are relative to the user of the ultrasonic bone scalpel; the end furthest from the operator is the back end, and the end closest to the operator is the front end.

[0020] Principles and advantages

[0021] To obtain a high-amplitude and high-safety ultrasonic bone scalpel, this invention addresses both material composition and structural design.

[0022] To achieve a high-amplitude, high-safety ultrasonic bone scalpel, this invention innovates in structural design. First, based on the theory of half-wave oscillators, when ultrasonic waves propagate from one medium to another, reflected and transmitted waves are generated at the interface. When the incident and reflected waves interfere with each other in the medium, a standing wave is formed.

[0023] The wave equation for the incident wave is: y1=Acos(wt-kx)

[0024] The wave equation for the reflected wave is: y² = Acos(wt + kx)

[0025] In the formula, A is the amplitude, w is the angular frequency, t is a certain time, k is the wave number, and x is a particle at a certain position. The wave equation reflects the displacement of each particle relative to its respective equilibrium position at a certain time during the wave process.

[0026] When two waves superimpose, the resulting wave, or standing wave, is: y = y1 + y2 = 2Acoskxcoswt. Therefore, the amplitude of the standing wave is Am = 2Acoskx, showing that the amplitude of the standing wave depends on the position but not on the vibration time.

[0027] When the amplitude is at its maximum, the position x satisfies |coskx|=1, that is, kx=2πx / λ=nπ, then x=n*λ / 2 (n=0,±1,±2,…). These positions are called antinodes.

[0028] When the amplitude is at its minimum, the position x satisfies |coskx|=0, that is, kx=2πx / λ=(n+1 / 2)π, then x=(2n+1)*λ / 4 (n=0, ±1, ±2,…). These positions are called nodes.

[0029] The inventors desired the maximum amplitude at the output of the vibration system. Based on the positional requirements of the antinodes in a standing wave, they designed the length of the vibration system to be an integer multiple of half a wavelength. Therefore, the length of the piezoelectric transducer is an integer multiple of half a wavelength, and the sum of the lengths of the amplitude transformer and the cutter head is also an integer multiple of half a wavelength. This allows the maximum amplitude to be obtained at the output of the vibration system, i.e., at the position of the cutter head.

[0030] Secondly, the vibration amplitude of piezoelectric transducers is typically only a few micrometers, which is insufficient for the needs of ultrasonic surgery. Therefore, an amplitude transformer needs to be installed in front of the transducer. Mechanical energy is transferred to the amplitude transformer through the front cover plate, and the ultrasonic energy is concentrated through interface changes, thereby amplifying the output amplitude. This invention uses a composite amplitude transformer composed of single shapes to improve output performance. By adjusting the diameter of the large and small cylinders at the cutter head position (α=D1 / D2=4~5) and the transition R angle (R=0.5·1 / α·L1), the amplitude ratio is increased, making the overall amplitude transformer ratio exceed 10 times.

[0031] Third, the cutting section of the ultrasonic bone scalpel tip is designed with multiple serrations, allowing for rapid bone removal while maintaining normal bone-grinding capabilities due to its thinness. Additionally, the small front end and large rear end provide the surgeon with a clear field of vision. A cavity is also incorporated to aid in the removal of debris and reduce temperature in the cutting area. The hollow channels within the entire ultrasonic bone scalpel allow for the drainage of tissue debris through negative pressure within the inner bore.

[0032] In summary, this utility model discloses an ultrasonic bone scalpel for joint surgery, comprising a piezoelectric transducer, an amplitude transformer, and a cutting head. By designing the cutting head with a high amplitude ratio and a serrated structure, the output amplitude and cutting speed can be significantly improved while ensuring surgical safety. It has the advantages of simple design, low manufacturing cost, large amplitude, and high safety, making it very suitable for application in ultrasonic bone scalpels for joint surgery. Attached Figure Description

[0033] Figure 1 This is a front view of the ultrasonic bone scalpel of this utility model;

[0034] Figure 2 This is a cross-sectional view of the ultrasonic bone scalpel of this utility model;

[0035] Figure 3 This is an enlarged view of the cutting part of the ultrasonic bone scalpel of this utility model. Detailed Implementation

[0036] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the relevant utility model and not intended to limit the scope of the utility model. Furthermore, it should be noted that, for ease of description, only the parts relevant to the utility model are shown in the accompanying drawings.

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] Figure 1 , 2Figures 3 and 4 show a front view, a sectional view, and an enlarged view of the cutting portion of an embodiment of the ultrasonic bone scalpel of this application, respectively. The ultrasonic bone scalpel is 230 mm long and operates at a frequency of 30 kHz. It includes a piezoelectric transducer 1, an amplitude transformer 2, and a cutter head 3. The amplitude transformer 2 is disposed at the front end of the piezoelectric transducer 1, and the cutter head 3 is disposed at the front end of the amplitude transformer 2. The amplitude transformer 2 is threadedly connected to the piezoelectric transducer 1, and the cutter head 3 is threadedly connected to the amplitude transformer 2.

[0039] The length of the cutter head 3 is 57.5 mm, including a large end cylinder 31, a transition radius 32, a small end cylinder 33, and a cutting part 34. The length of the large end cylinder 31 is 5.75 mm and the diameter is 20 mm. The length of the small end cylinder 33 is 34.5 mm and the diameter is 4 mm. The transition radius 32 is 5.75 mm. The width of the cutting part 34 is 4 mm and the thickness is 2 mm. There is an elliptical clearance groove 341 in the middle of the cutting part, and both side walls along the axial direction are equipped with serrations 342. The number of serrations on each side is 25.

[0040] The piezoelectric transducer 1 includes bolts 11, a rear cover plate 12, a conductive sheet 13, a piezoelectric ceramic sheet 14, and a front cover plate 15. The rear cover plate 12 is located at the rear end of the piezoelectric transducer 1, and the bolts 11 are provided at the rear end of the rear cover plate 12. The front cover plate 15 is located at the front end of the piezoelectric transducer 1. The conductive sheet 13 and the piezoelectric ceramic sheet 14 are disposed between the rear cover plate 12 and the front cover plate 15, and the conductive sheet 13 and the piezoelectric ceramic sheet 14 are spaced apart from each other. The rear cover plate 12, the conductive sheet 13, the piezoelectric ceramic sheet 14, and the front cover plate 15 are connected together by bolts 11.

[0041] The piezoelectric transducer 1 is 115mm long and 20mm in diameter. There are 4 piezoelectric ceramic sheets 14 made of lead zirconate titanate (PZT). The amplitude transformer 2 is 57.5mm long and 20mm in diameter.

[0042] The ultrasonic bone scalpel also includes a hollow tube 4, which extends from the bolt 11 of the piezoelectric transducer 1 along the axial direction to the small end cylinder 33 of the scalpel head 3, with a tube diameter of 3mm.

[0043] Bolt 11 is made of TC4, rear cover plate 12 is made of 90WNiFe, conductive sheet 13 is made of pure copper, front cover plate 14 is made of TC4, and amplitude transformer 2 and cutter head 3 are both made of 440A stainless steel.

[0044] The embodiments of the present invention have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention is not limited to the specific embodiments described above; these embodiments are merely illustrative and not limiting. Those skilled in the art, under the guidance of the present invention, can make many modifications without departing from the spirit and scope of the claims, and all such modifications fall within the protection scope of the present invention.

Claims

1. An ultrasonic bone scalpel for joint surgery, characterized in that, It includes a piezoelectric transducer (1), an amplitude transformer (2) and a cutter head (3), wherein the amplitude transformer (2) is located at the front end of the piezoelectric transducer (1) and the cutter head (3) is located at the front end of the amplitude transformer (2); The length of the cutter head (3) is L1 = N1·λ / 4, where N1 is a positive integer and λ is the sound wavelength. It includes a large end cylinder (31), a transition R angle (32), a small end cylinder (33), and a cutting part (34). The length of the large end cylinder (31) is l1 = 0.1·L1, the length of the small end cylinder (33) is l2 = 0.6·L1, and the transition R angle (32) is R = 0.5·1 / α·L1. Where the diameter ratio of the large and small end cylinders is α = D1 / D2 = 4~5, D1 and D2 are the diameters of the large and small end cylinders, respectively, where D1 = 20~25mm. The width of the cutting part (34) is 4~5mm and the thickness is 2~3mm. The middle of the cutting part has an elliptical clearance groove (341), and both side walls along the axial direction are equipped with serrations (342). The number of serrations on one side is 20~25. The length of the piezoelectric transducer (1) is L2 = N2·λ / 2, where N2 is a positive integer, λ is the acoustic wavelength, and its diameter is 20~25mm. The amplitude rod (2) is cylindrical, with a length L1=N1*λ / 4, where N1 is a positive integer, λ is the sound wavelength, and its diameter is 20~25mm.

2. The ultrasonic bone scalpel for joint surgery according to claim 1, characterized in that: The ultrasonic bone scalpel also includes a hollow tube (4), which extends from the bolt (11) of the piezoelectric transducer (1) along the axial direction to the small end cylinder (33) of the scalpel head (3), and the diameter of the tube is 2~3mm.

3. The ultrasonic bone scalpel for joint surgery according to claim 1, characterized in that: The piezoelectric transducer (1) includes a bolt (11), a rear cover plate (12), a conductive sheet (13), a piezoelectric ceramic sheet (14), and a front cover plate (15). The rear cover plate (12) is located at the rear end of the piezoelectric transducer (1), and the bolt (11) is provided at the rear end of the rear cover plate (12). The front cover plate (15) is located at the front end of the piezoelectric transducer (1). The conductive sheet (13) and the piezoelectric ceramic sheet (14) are disposed between the rear cover plate (12) and the front cover plate (15). The rear cover plate (12), the conductive sheet (13), the piezoelectric ceramic sheet (14), and the front cover plate (15) are connected together by the bolt (11).

4. The ultrasonic bone scalpel for joint surgery according to claim 1, characterized in that: The amplitude transformer (2) is connected to the piezoelectric transducer (1) by a thread, and the cutter head (3) is connected to the amplitude transformer (2) by a thread.

5. The ultrasonic bone scalpel for joint surgery according to claim 3, characterized in that: The bolt (11) is made of TC4, the rear cover plate (12) is made of 90WNiFe, the conductive sheet (13) is made of pure copper, and the front cover plate (15) is made of TC4.

6. The ultrasonic bone scalpel for joint surgery according to claim 1, characterized in that: The materials of the amplitude transformer (2) and the cutter head (3) are both 440A stainless steel.

7. The ultrasonic bone scalpel for joint surgery according to claim 1, characterized in that, The ultrasonic bone scalpel operates at a frequency of 25~35kHz.

8. The ultrasonic bone scalpel for joint surgery according to claim 1, characterized in that: The ultrasonic bone scalpel has a length of 230mm, 345mm, or 460mm.

9. The ultrasonic bone scalpel for joint surgery according to claim 3, characterized in that: The number of the piezoelectric ceramic sheets (14) is 4.

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