Sawtooth ultrasonic cutting blade with variable tooth pitch
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-08-11
- Publication Date
- 2026-03-24
AI Technical Summary
Traditional bone saws face challenges in initiating cuts, producing curved or angled cuts, and achieving precise bone cutting, especially in large and strong bony structures like the vertebrae and spinal arches, while existing ultrasonic bone cutting blades struggle with access and non-bone tissue damage.
An ultrasonic surgical instrument with a convex arcuate blade design featuring different tooth depths and pitches along its edges, connected to an ultrasonic vibration source, allowing for precise bone cutting with reduced non-bone tissue damage.
Facilitates precise bone cutting, particularly in vertebral regions, with reduced invasiveness and improved access to complex bone structures, minimizing damage to non-targeted soft tissues.
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Abstract
Description
[Technical field]
[0001] The present invention relates to ultrasonic instruments and, more particularly, to ultrasonic cutting blades that are particularly useful in surgical applications for cutting tissue such as cartilage and bone. [Background technology]
[0002] In the field of orthopedic surgery, the cutting of living bone is essential for many procedures, including the restoration of tissue structures damaged by accident, the grafting of healthy bone to areas damaged by disease, or the correction of congenital facial defects such as a receding jawline. For centuries, these tasks have been performed with the aid of a device called a bone saw.
[0003] Traditional bone saws fall into a few basic categories: Manual saws or drills are just that, hand-held devices that require the operator to move the device in a manner similar to a carpenter's tool. Powered devices are either reciprocating or rotary, whether electric or pneumatic. Reciprocating devices use a flat, sword-like blade, with the back and forth motion provided by a motor instead of the hand. Rotary devices use a rotary motor to spin a drill bit, or a blade with teeth arranged around its periphery similar to a table saw blade. All of these traditional bone saws are still used in medical procedures around the world today.
[0004] Although conventional saws are practical, they have many disadvantages. Band saws or reciprocating saws, for example, are not easy to initiate and direct the cut. The cut must start from the edge or a starter hole must be used. To create the starter hole, a drill or similar instrument is used to drill a hole in the bone. A cutting blade is then inserted into the drilled hole. The user can then begin cutting. Alternatively, a rotary type blade may be used. However, when a rotary blade is used, the cut must follow a relatively straight path to avoid binding the cutting blade in the cut. With all cutting blades, the ability to produce curved or angled cuts with the selected cutting blade is very limited. A relatively thick cutting blade produces a wide cut, so that a large thickness of living bone is lost in the cutting procedure. The surgeon wants this width to be as thin as possible in most procedures where restoration is required.
[0005] Ultrasonic bone cutting blades, such as those disclosed in US Pat. Nos. 5,993, 6,149, 6,151, 6,163, 6,171, 6,182, 6,193, 7,146, 7,198, 7,203, 7,211, 7,222, 7,313, 7,321, 7,414, 7,516, 7,521, 7,611, 7,721, 7,821, 7,911, 7,172, 7,198, 7,222, 7,236, 7,317, 7,417, 7,521, 7,611, 7,721, 7,821, 7,911, 7,172, 7,222, 7,317, 7,417, 7,521, 7,611, 7,721, 7,821, 7,911, 7,911, 7,172, 7,198, 7,222, 7,236, 7,242, 7,242, 7,317, 7,317, 7,417, 7,521, 7,611, 7,721, 7,731, 7,821, 7,911, 7,911, 7,821, 7,911, 7,911, 7,911, 7,172 ... [Prior art documents] [Patent documents]
[0006] [Patent Document 1] U.S. Pat. No. 5,261,922 [Patent Document 2] U.S. Patent No. 6,379,371 [Patent Document 3] U.S. Pat. No. 6,443,969 [Patent Document 4] U.S. Patent No. 6,763,673 [Patent Document 5] U.S. Pat. No. 8,888,783 [Patent Document 6] U.S. Patent No. 9,387,005 [Patent Document 7] U.S. Pat. No. 9,320,528 [Patent Document 8] U.S. Design Registration No. 680,218 [Patent Document 9] U.S. Design Registration No. 667,117 Summary of the Invention [Problem to be solved by the invention]
[0007] SUMMARY OF THE PRESENT EMBODIMENT The present invention aims to provide an improved ultrasonic surgical instrument or probe for ablating or cutting bone tissue and cartilage.
[0008] It is a further object of the present invention to provide such an ultrasonic surgical instrument or probe which facilitates bone cutting procedures, particularly, but not exclusively, spinal bone cutting procedures.
[0009] It is yet another object of the present invention to provide such an ultrasonic surgical instrument or probe which is less likely to cut non-bone tissue.
[0010] It is yet another object of the present invention to provide a surgical intervertebral space preparation procedure that can be used to access an intervertebral disc in a surgical procedure.
[0011] These and other objects of the present invention will become apparent from the drawings and description herein. While all of the objects of the present invention are achieved in at least one embodiment of the present invention, there is no embodiment that achieves every object of the present invention. [Means for solving the problem]
[0012] The ultrasonic surgical instrument of the present invention includes a substantially planar blade body having a pair of oppositely facing side surfaces, a pair of linear longitudinally extending edges, and a convex arcuate distal edge contiguous with the linear longitudinally extending edges. A shank is integral with the blade body at the distal end and includes a connector proximally for operatively connecting the blade to a source of ultrasonic mechanical vibration. The blade body includes a continuous arrangement of teeth along the convex arcuate distal edge and at least one of the linear longitudinally extending edges, the teeth including a first subset of teeth along the convex arcuate distal edge and a second subset of teeth along at least one of the linear longitudinally extending edges. The first subset of teeth exhibits a first tooth height and a first inter-tooth tooth space depth, while the second subset of teeth has a second tooth height and a second inter-tooth tooth space depth. The first tooth depth and the second tooth depth are different, and the depth of the tooth space between the first teeth is different from the depth of the tooth space between the second teeth.
[0013] Another feature of the ultrasonic surgical instrument of the present invention is that the first tooth height and the tooth gap depth between the first teeth are each uniform among the first subset of teeth, and the second tooth height and the tooth gap depth between the second teeth are each uniform among the second subset of teeth.
[0014] According to another feature of the present invention, the first tooth depth and the tooth gap depth between the first teeth are smaller than the second tooth depth and the tooth gap depth between the second teeth, respectively. Specifically, the first tooth depth is between about 0.60 and about 0.85 times the second tooth depth, and the tooth gap depth between the first teeth is between about 0.60 and about 0.85 times the second tooth depth. Preferably, the first tooth depth is about 0.80 times the second tooth depth, and the first tooth gap depth is about 0.80 times the second tooth gap depth.
[0015] As noted above, the first tooth depth and the space depth between the first teeth may be uniform among the first subset of teeth, and the second tooth depth and the space depth between the second teeth are uniform among the second subset of teeth. However, this is not necessarily the case. For example, the first tooth depth and the space depth between the first teeth may vary from a minimum at the distal-most end of the arcuate distal edge of the blade and gradually increase on each side toward the respective longitudinally extending edge.
[0016] In a preferred embodiment of the invention, the teeth in a continuous array of teeth are all triangular with the same angle and have a common angle between opposite sides, such that if the characteristic tooth depth of a first subset of teeth is smaller than the characteristic tooth depth of a second subset of teeth, then the pitch of the teeth of the first subset along the distal edge of the blade will necessarily be smaller than the pitch of the teeth of a second subset along one or two longitudinally extending edges of the blade.
[0017] In accordance with this preferred embodiment, the ultrasonic surgical instrument of the present invention includes a substantially planar blade body having a pair of oppositely facing side surfaces, a pair of linear longitudinally extending edges, and a convex arcuate distal edge contiguous with the linear longitudinally extending edges, with a shank integral with the blade body distally and including a connector proximally for operatively connecting the blade to a source of ultrasonic mechanical vibration. The blade body includes a continuous arrangement of teeth along the convex arcuate distal edge and at least one of the linear longitudinally extending edges, including a first subset of teeth along the convex arcuate distal edge and a second subset of teeth along at least one of the linear longitudinally extending edges. The first subset of teeth exhibit a first intertooth distance or pitch and the second subset of teeth has a second intertooth distance, where the first intertooth distance or pitch and the second intertooth distance or pitch are different.
[0018] According to a further feature of the invention, the first inter-tooth distance or pitch is uniform among the first subset of teeth and the second inter-tooth distance or pitch is uniform among the second subset of teeth.
[0019] According to a more particular feature of the present invention, the first inter-tooth distance or pitch is less than the second inter-tooth distance or pitch. The teeth in the continuous array of teeth may preferably have a common angle between opposing sides in a triangle all having the same angle.
[0020] Preferably, the first interdental spacing or pitch is between about 0.60 and about 0.85 times the second interdental spacing or pitch.
[0021] The ultrasonic instruments of the present invention facilitate the performance of spinal procedures, particularly by reducing the likelihood of damage to non-target soft tissue. Smaller depths along the distal end of the blade are less invasive than longer depths to tissue not intended to be removed, such as spinal soft tissue.
[0022] Although uniform tooth sharpness (angle between the mutually inclined tooth edges) is preferred primarily for manufacturing reasons, it is envisioned that the tooth angle along the longitudinally extending edges may be reduced to reduce the pitch and thereby produce a finer cut and smoother kerf. [Brief description of the drawings]
[0023] [Figure 1] FIG. 1 is a top view of an ultrasonic surgical instrument or probe of the present invention, specifically an ultrasonic surgical blade, with the bottom view being identical to the top view. [Diagram 2] 2 is a rear, left side and top perspective view of the ultrasonic surgical instrument or probe of FIG. 1. [Diagram 3] FIG. 3 is a front view of the ultrasonic surgical instrument or probe of FIGS. 1 and 2. [Figure 4] FIG. 4 is a rear view of the ultrasonic surgical instrument or probe of FIGS. 1-3. [Diagram 5] FIG. 5 is a right side view of the ultrasonic surgical instrument or probe of FIGS. 1-4, with the left side view being identical thereto. [Figure 6] FIG. 6 is a cross-sectional view of the ultrasonic surgical instrument or probe of FIGS. 1-5 taken along its longitudinal axis. [Figure 7] FIG. 2 is a partial top or bottom enlarged view showing detail VI of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] As shown in the drawings, ultrasonic surgical instrument or probe 10 includes a substantially planar blade body 12 having a pair of oppositely facing parallel side or major faces 14, 16, a pair of straight, substantially longitudinally extending edges 18, 20, and a convex, arcuate distal edge 22 adjacent and contiguous with the straight, longitudinally extending edges. The longitudinal edges 18, 20 converge slightly toward one another at the distal end of the blade body 12 and define several degrees of arc relative to one another.
[0025] A laterally enlarged proximal portion or shank 24 is integral with the blade body 12 distally and includes an externally threaded connector 26 proximally for operatively coupling the blade body ("blade") 12 to a source of ultrasonic mechanical vibrational energy 27, specifically a stack of piezoelectric crystal elements (not shown) and a waveform generator (not shown) which applies ultrasonic frequency voltage to the piezoelectric stack. The shank 24 is formed with a pair of oppositely facing flats 40, 42 engageable with a wrench (not shown) for screwing the instrument or probe 10 to an ultrasonic handpiece, and specifically the piezoelectric crystal stack therein.
[0026] The shank 24 and blade body 12 are formed with collinear passages, holes or lumens 44, 46 of different diameters which communicate with each other and with a through slot 48 at the distal end which extends longitudinally and axially through a portion of the blade body 12. A cooling fluid, typically water-based, is delivered through the passages 44, 46 and into the slot 48 to maintain the temperature of the blade 12 and / or adjacent living tissue within a biologically safe range.
[0027] The blade body 12 comprises a continuous arrangement of teeth along the convex-arcuate distal edge 22 and at least one, but preferably both, of the longitudinally extending edges 18, 20, including a first subset of teeth 28 along the convex-arcuate distal edge 22 and a second subset of teeth 30, 32 along the longitudinally extending edges 18, 20. The teeth 28 exhibit a first tooth depth TL1 and associated first inter-tooth space depths (not labeled) that are typically equal to one another, while the teeth 30, 32 have a second tooth depth TL2 and associated second inter-tooth space depths (not labeled) that are typically equal thereto. The tooth depths TL1 and TL2 are different, and thus the tooth depths between the first teeth and the tooth depths between the second teeth are different. A conical tapered surface 50 at the distal end of the through slot 48 serves to distribute the coolant along the length of the arcuate edge 22.
[0028] Preferably, but not necessarily, the tooth depth TL1 and associated inter-tooth space depth are uniform among all teeth 28, and the tooth depth TL2 and associated inter-tooth space depth are uniform among at least all teeth 30 or 32. However, the tooth depth TL1 and associated first inter-tooth space depth of teeth 28 may vary from a minimum at the distal-most end of arcuate distal edge 22 and gradually increase on each side toward the respective longitudinally extending edges 30, 32 of blade body 12. Alternatively, teeth 30 and 32 may be provided with different common tooth depths TL2 and inter-tooth space depths for applications targeting areas of different bone structure or density.
[0029] Preferably, the tooth depth TL1 of tooth 28 and the inter-tooth space depth are less than the tooth depth TL2 of teeth 30, 32 and the inter-tooth space depth, respectively. Specifically, the tooth depth TL1 is between about 0.60 and about 0.85 times the tooth depth TL2, with the associated inter-tooth space depths exhibiting the same ratio. Preferably, the tooth depth TL1 is about 0.80 times the tooth depth TL2, e.g., the tooth depth TL1 is 0.0016 inches (about 0.041 mm) and the tooth depth TL2 is 0.0020 inches (about 0.051 mm). Accordingly, the inter-tooth space depth of tooth 28 is 0.80 times the second inter-tooth space depth of teeth 30 and / or 32.
[0030] The teeth 28, 30, 32 are preferably all triangular with common angles a1, a2 between the opposite sides. This conformity of shape simplifies manufacturing. However, the angles a1, a2 may differ from each other. For example, the angle a1 may be greater than the angle a2. If the tooth depth TL2 remains unchanged, the reduction of the angle a2 and the resulting sharpening of the teeth 30, 32 correlates with a reduction in their pitch TP2. Such a reduction in the pitch may be done to increase the fineness of the cutting action of the edges 30, 32.
[0031] The ultrasonic surgical instrument of the present invention thus includes a planar blade body 12 with oppositely facing sides 14, 16, straight longitudinally extending edges 18, 20, and a convex, arcuate distal edge 22 continuous with edges 18, 20, and includes a shank 24 distally integral with the blade body 12 and including a connector 26 for operatively connecting the blade 12 to a vibration source 27. As described above, the blade body 12 includes a continuous arrangement of teeth along the convex, arcuate distal edge 22 and at least one of the longitudinally extending edges 18, 20, including teeth 28 along the distal edge 22 and teeth 30, 32 along the longitudinally extending edges 30, 32. The teeth 28 exhibit a first intertooth distance or pitch TP1, and the teeth 30 and / or 32 have a second intertooth distance or pitch TP2 that may be different from the intertooth distance or pitch TP1.
[0032] In a preferred embodiment, the intertooth distance or pitch TP1 is uniform between teeth 28 and the intertooth distance or pitch TP2 is uniform between teeth 30 and / or 32. The intertooth distance or pitch TP1 is smaller than the intertooth distance or pitch TP2, where the teeth in a consecutive tooth sequence all have a common angle (a1=a2, e.g. 60°) between opposite sides of a triangle with the same angle. Alternatively, the manufacture, and in particular the magnitude of the angles a1, a2, may be varied so that the pitches TP1 and TP2 are the same.
[0033] The ultrasonic instrument or probe 10 allows for finer control of the cut in spinal surgery by reducing the action of the probe on tissue distal to the blade body 12. The shorter tooth depth TL1 limits the invasiveness of the arcuate edge 22, reducing the cutting action distally compared to the rate of ultrasonic cutting along the longitudinal edges 18, 20.
[0034] Although the present invention has been described with respect to specific embodiments and applications, those skilled in the art may, in light of this teaching, produce additional embodiments and improvements without departing from the spirit or beyond the scope of the present invention. For example, the pitch and dentition (or depth or height) may vary gradually from a characteristic value along the edges 30, 32 to a different characteristic value along the tip or distal edge 22. Alternatively, as shown diagrammatically in FIG. 7, they may vary in a step between a first predetermined point between edges 18 and 22 and another demarcating point between edges 20 and 22. It is therefore to be understood that the drawings and description herein are provided by way of example to facilitate understanding of the present invention and should not be construed as limiting its scope. [Explanation of symbols]
[0035] 10 Ultrasonic surgical instruments or probes 12 Blade body 14, 16 A pair of parallel oppositely facing sides or main faces 18, 20 A pair of straight, substantially longitudinally extending edges 22 Convex, arcuate distal edge 24 Proximal portion or shank 26 Connectors 27 Vibration source 28, 30, 32 teeth 44, 46 Flow path 48 Through Slots 50 Tapered surface a1, a2 angle TL1 First tooth TL2 Second Tooth
Claims
1. An instrument comprising a proximal portion and a blade positioned at the distal end of the proximal portion, The aforementioned proximal portion has a channel configured to deliver fluid through it and is configured to be coupled to an ultrasonic energy source. An instrument wherein the blade has a through-slot that is in fluid communication with the flow path, the through-slot is configured to extend longitudinally through a portion of the blade to deliver the fluid to a region adjacent to the blade, and the blade includes a plurality of teeth arranged on at least a portion of the edge of the blade, the plurality of teeth being configured to cut into biological tissue.
2. The apparatus according to claim 1, wherein the blade includes a first side surface and a second side surface parallel to the first side surface, and the through slot extends between the first side surface and the second side surface.
3. The apparatus according to claim 1, wherein the flow path is a first flow path, and the blade further includes a second flow path that is collinear with the first flow path and configured to deliver the fluid to the through-slot.
4. The apparatus according to claim 1, wherein the blade has a pair of longitudinally extending edges and a convex, arc-shaped distal edge continuous with the pair of longitudinally extending edges.
5. The apparatus according to claim 4, wherein the plurality of teeth include a first set of teeth and a second set of teeth different from the first set of teeth.
6. The instrument according to claim 5, wherein the first set of teeth is arranged on at least a portion of the distal edge of the blade, and the second set of teeth is arranged on at least a portion of the pair of longitudinally extending edges.
7. The instrument according to claim 6, wherein the first set of teeth has a first tooth height, the second set of teeth has a second tooth height, and the first tooth height is smaller than the second tooth height.
8. The apparatus according to claim 6, wherein the first set of teeth has a first pitch, the second set of teeth has a second pitch, and the first pitch is smaller than the second pitch.
9. An instrument comprising a proximal portion and a blade positioned at the distal end of the proximal portion, The aforementioned proximal portion has a channel configured to deliver fluid through it and is configured to be coupled to an ultrasonic energy source. The blade includes a first side surface and a second side surface parallel to the first side surface, and a through-slot extends between the first side surface and the second side surface, and the through-slot is configured to communicate with the flow path and to deliver the fluid to a region adjacent to the blade. The instrument further comprises a plurality of teeth arranged on at least a portion of the edge of the blade, the plurality of teeth configured to cut into biological tissue.
10. The apparatus according to claim 9, wherein the blade has a pair of longitudinally extending edges and a convex, arc-shaped distal edge continuous with the pair of longitudinally extending edges.
11. The apparatus according to claim 10, wherein the plurality of teeth include a first set of teeth and a second set of teeth different from the first set of teeth.
12. The instrument according to claim 11, wherein the first set of teeth is arranged on at least a portion of the distal edge of the blade, and the second set of teeth is arranged on at least a portion of the pair of longitudinally extending edges.
13. The instrument according to claim 12, wherein the first set of teeth has a first tooth height, the second set of teeth has a second tooth height, and the first tooth height is smaller than the second tooth height.
14. The apparatus according to claim 12, wherein the first set of teeth has a first pitch, the second set of teeth has a second pitch, and the first pitch is smaller than the second pitch.
15. The device according to claim 12, wherein the tooth height in the first set of teeth changes from a minimum value at the most distal end of the distal margin and gradually increases toward each of the longitudinally extending margins of the pair of longitudinally extending margins.
16. The device according to claim 12, wherein the tooth height in the first set of teeth is uniform among the first set of teeth, and the tooth height in the second set of teeth is uniform among the second set of teeth.
17. An instrument comprising a proximal portion and a blade positioned at the distal end of the proximal portion, The aforementioned proximal portion has a channel through which it passes and is configured to be coupled to an ultrasonic mechanical vibration source. The blade has a pair of longitudinally extending edges and a distal edge continuous with the pair of longitudinally extending edges, and a through slot extending through a portion of the blade. The blade further comprises a plurality of teeth, including a first set of teeth positioned on at least a portion of the distal edge and a second set of teeth positioned on at least a portion of the pair of longitudinally extending edges, wherein the first set of teeth has a first tooth height and a first pitch, and the second set of teeth has a second tooth height greater than the first tooth height and a second pitch greater than the first pitch, and the plurality of teeth are configured to cut into biological tissue.
18. The apparatus according to claim 17, wherein the flow path is configured to deliver fluid, and the through-slot of the blade is in fluid communication with the flow path and is configured to deliver the fluid to an area adjacent to the blade.
19. The apparatus according to claim 17, wherein the blade includes a first side surface and a second side surface parallel to the first side surface.
20. The apparatus according to claim 19, wherein the through-slot extends between the first side surface and the second side surface.
21. The apparatus according to claim 17, wherein the through slot extends longitudinally through a portion of the blade.
22. The apparatus according to claim 17, wherein the plurality of teeth are a continuous arrangement of teeth along the distal margin and the pair of longitudinally extending margins.
23. The device according to claim 17, wherein the tooth height of the first set of teeth changes from a minimum value at the most distal end of the distal margin and gradually increases toward each of the longitudinally extending margins of the pair of longitudinally extending margins.
24. The device according to claim 17, wherein the tooth height in the first set of teeth is uniform among the first set of teeth, and the tooth height in the second set of teeth is uniform among the second set of teeth.