SERRATED ULTRASONIC CUTTING BLADE WITH VARIED TOOTH PITCH

Abstract

An ultrasonic blade is provided along a convexly arcuate distal edge and at least one longitudinal edge with a continuous array of teeth including a first subset of teeth along the convexly arcuate distal edge and a second subset of teeth along the at least one straight longitudinal edge. The teeth along the convexly arcuate distal edge differ in tooth length and optionally in inter-tooth separation or pitch from the teeth along one or both of the longitudinal edges.

Claims

1. An ultrasonic surgical tool comprising: a substantially planar blade body having a pair of opposed lateral surfaces, a pair of straight longitudinal edges and a convexly arcuate distal edge contiguous with said straight longitudinal edges, a shank integral on a distal side with said blade body and provided at a proximal side with a connector for operatively linking the blade to a source of ultrasonic mechanical vibrations, said blade body being provided along said convexly arcuate distal edge and at least one of said straight longitudinal edges with a continuous array of teeth including a first subset of teeth along said convexly arcuate distal edge and a second subset of teeth along said at least one of said straight longitudinal edges, said first subset of teeth exhibiting a first tooth length and a first inter-tooth gap depth, said second subset of teeth having a second tooth length and a second inter-tooth gap depth, said first tooth length being different from said second tooth length, said first inter-tooth gap depth being different from said second inter-tooth gap depth.

2. The ultrasonic surgical tool defined in claim 1 wherein said first tooth length and said first inter-tooth gap depth are each uniform among said first subset of teeth, and said second tooth length and said second inter-tooth gap depth being each uniform among said second subset of teeth.

3. The ultrasonic surgical tool defined in claim 2 wherein said first tooth length and said first inter-tooth gap depth are smaller than said second tooth length and said second inter-tooth gap depth, respectively.

4. The ultrasonic surgical tool defined in claim 3 wherein said first tooth length is between about 0.60 and about 0.85 times said second tooth length, said first inter-tooth gap depth being between about 0.60 and about 0.85 times said second inter-tooth gap depth.

5. The ultrasonic surgical tool defined in claim 4 wherein said first tooth length is about 0.80 times said second tooth length, said first inter-tooth gap depth being about 0.80 times said second inter-tooth gap depth.

6. The ultrasonic surgical tool defined in claim 3 wherein the teeth of said continuous array of teeth are all isometrically triangular and bear a common angle between opposing edges, the teeth of said first subset of teeth having a first pitch and the teeth of said second subset of teeth having a second pitch, said first pitch being smaller than said second pitch.

7. The ultrasonic surgical tool defined in claim 1 wherein said first tooth length and said first inter-tooth gap depth are smaller than said second tooth length and said second inter-tooth gap depth, respectively.

8. The ultrasonic surgical tool defined in claim 7 wherein said first tooth length is between about 0.60 and about 0.85 times said second tooth length, said first inter-tooth gap depth being between about 0.60 and about 0.85 times said second inter-tooth gap depth.

9. The ultrasonic surgical tool defined in claim 8 wherein said first tooth length is about 0.80 times said second tooth length, said first inter-tooth gap depth being about 0.80 times said second inter-tooth gap depth.

10. The ultrasonic surgical tool defined in claim 7 wherein the teeth of said continuous array of teeth are all isometrically triangular and bear a common angle between opposing edges, teeth of said first subset of teeth having a first pitch and teeth of said second subset of teeth having a second pitch, said first pitch being smaller than said second pitch.

11. The ultrasonic surgical tool defined in claim 1 wherein the teeth of said continuous array of teeth are all isometrically triangular and bear a common angle between opposing edges, teeth of said first subset of teeth having a first pitch and teeth of said second subset of teeth having a second pitch different from said first pitch.

12. An ultrasonic surgical tool comprising: a substantially planar blade body having a pair of opposed lateral surfaces, a pair of straight longitudinal edges and a convexly arcuate distal edge contiguous with said straight longitudinal edges, a shank integral on a distal side with said blade body and provided at a proximal side with a connector for operatively linking the blade to a source of ultrasonic mechanical vibrations, said blade body being provided along said convexly arcuate distal edge and at least one of said straight longitudinal edges with a continuous array of teeth including a first subset of teeth along said convexly arcuate distal edge and a second subset of teeth along said at least one of said straight longitudinal edges, said first subset of teeth exhibiting a first inter-tooth separation or pitch and said second subset of teeth having a second inter-tooth separation, said first inter-tooth separation or pitch being different from said second inter-tooth separation or pitch.

13. The ultrasonic surgical tool defined in claim 12 wherein said first inter-tooth separation or pitch is uniform among said first subset of teeth, and said second inter-tooth separation or pitch is uniform among said second subset of teeth.

14. The ultrasonic surgical tool defined in claim 13 wherein said first inter-tooth separation or pitch is smaller than said second inter-tooth separation or pitch.

15. The ultrasonic surgical tool defined in claim 14 wherein the teeth of said continuous array of teeth are all isometrically triangular and bear a common angle between opposing edges.

16. The ultrasonic surgical tool defined in claim 13 wherein said first inter-tooth separation or pitch is between 0.60 and 0.85 times said second inter-tooth separation or pitch.

17. The ultrasonic surgical tool defined in claim 12 wherein said first inter-tooth separation or pitch is smaller than said second inter-tooth separation or pitch.

18. The ultrasonic surgical tool defined in claim 17 wherein said first inter-tooth separation or pitch is between 0.60 and 0.85 times said second inter-tooth separation or pitch.

19. The ultrasonic surgical tool defined in claim 12 wherein the teeth of said continuous array of teeth are all isometrically triangular and bear a common angle between opposing edges.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a top plan view of an ultrasonic surgical tool or probe, particularly an ultrasonic surgical blade, in accordance with the present invention, a bottom plan view being identical to the top plan view.

[0023] FIG. 2 is a rear, left side and top perspective view of the ultrasonic surgical tool or probe of FIG. 1.

[0024] FIG. 3 is a front elevational view of the ultrasonic surgical tool or probe of FIGS. 1 and 2.

[0025] FIG. 4 is a rear elevational view of the ultrasonic surgical tool or probe of FIGS. 1-3.

[0026] FIG. 5 is a right side elevational view of the ultrasonic surgical tool or probe of FIGS. 1-4, a left side elevation view being identical thereto.

[0027] FIG. 6 is longitudinal axial cross-sectional view of the ultrasonic surgical tool or probe of FIGS. 1-5.

[0028] FIG. 7 is partial top or bottom plan view thereof, on an enlarged scale, showing detail VI in FIG. 1.

DETAILED DESCRIPTION

[0029] As depicted in the drawings, an ultrasonic surgical tool or probe 10 includes a substantially planar blade body 12 having a pair of parallel opposed lateral surfaces or major faces 14 and 16, a pair of straight substantially longitudinal edges 18 and 20, and a convexly arcuate distal edge 22 contiguous and continuous with the straight longitudinal edges. Longitudinal edges 18 and 20 converge slightly towards one another at the distal end of blade body 12; longitudinal edges 18 and 20 are oriented at an angle of several degrees of arc relative to one another.

[0030] A transversely enlarged proximal portion or shank 24 is integral on a distal side with blade body 12 and provided on a proximal side with an externally threaded connector 26 for operatively coupling the blade body (“blade”) 12 to a source 27 of ultrasonic mechanical vibratory energy, particularly to a stack of piezoelectric crystal elements (not shown) and a waveform generator (not shown) that applies an ultrasonic-frequency voltage across the piezo-stack. Shank 24 is formed with a pair of opposed flats 40, 42 engageable by a wrench (not illustrated) for screwing the tool or probe 10 to an ultrasonic handpiece and particularly the piezoelectric crystal stack therein.

[0031] Shank 24 and blade body 12 are formed with co-linear channels, bores or lumens 44 and 46 of different diameters that communicate with one another and at a distal end with a through slot 48 extending longitudinally and axially along a portion of blade body 12. Liquid coolant, typically aqueous, is conveyed through channels 44 and 46 to slot 48 for maintaining the temperature of blade 12 and or adjacent biological tissue within a biologically safe range.

[0032] Blade body 12 is provided along convexly arcuate distal edge 22 and at least one but preferably both longitudinal edges 18 and 20 with a continuous array of teeth including a first subset of teeth 28 along convexly arcuate distal edge 22 and a second subset of teeth 30, 32 along longitudinal edges 18 and 20. Teeth 28 exhibit a first tooth length TL1 and an associated first inter-tooth gap depth (not designated) typically equal to one another, while teeth 30 and 32 have a second tooth length TL2 and a second inter-tooth gap depth (not designated) generally equal thereto. Tooth length TL1 differs from the tooth length TL2, and concomitantly the first inter-tooth gap depth differs from the second inter-tooth gap depth. A conically tapered surface 50 at a distal end of through slot 48 serves to distribute coolant to arcuate edge 22 along the length thereof.

[0033] Preferably, but not necessarily, tooth length TL1 and the associated inter-tooth gap depth are each uniform among teeth 28, while tooth length TL2 and the associated inter-tooth gap depth are each uniform among at least teeth 30 or 32. However, the lengths of teeth 28 and the associated first inter-tooth gap depth may vary from a minimum at an extreme distal tip of arcuate distal edge 22 and increase gradually on each side towards the respective longitudinal edge 30, 32 of blade body 12. Or one might provide teeth 30 and teeth 32 with different common tooth lengths TL2 and inter-tooth gap depths, where an application targets a region of different bone structures or densities.

[0034] Preferably, tooth length TL1 and the inter-tooth gap depth of teeth 28 are respectively smaller than tooth length TL2 and the inter-tooth gap depth of teeth 30, 32. Specifically, tooth length TL1 lies between approximately 0.60 and approximately 0.85 times tooth length TL2, the associated inter-tooth gap depths exhibiting the same proportionality. Preferably, tooth length TL1 is about 0.80 times tooth length TL2, for instance, where tooth length TL1 is 0.0016 inch while tooth length TL2 is 0.0020 inch. Concomitantly, the inter-tooth gap depth of teeth 28 is 0.80 times the second inter-tooth gap depth of teeth 30 and/or 32.

[0035] Teeth 28, 30, 32 are preferably all isometrically triangular and bear a common angle a1, a2 between opposing edges. This geometric congruence simplifies manufacture. However, angles a1 and a2 may differ from one another. For instance, angle a1 may be larger than angle a2. Where the tooth length TL2 is unchanged, the reduction in the angle a2 and the consequent increase in sharpness of teeth 30, 32 correlates to a reduction in a pitch TP2 thereof. Such a reduction in pitch may be implemented to increase the fineness of cutting action of edges 30, 32.

[0036] Thus, an ultrasonic surgical tool in accordance with the present invention comprises planar blade body 12 with opposed lateral surfaces 14 and 16, straight longitudinal edges 18 and 20 and convexly arcuate distal edge 22 contiguous with edges 18 and 20, with shank 24 integral on a distal side with blade body 12 and provided with connector 26 for operatively linking blade 12 to vibration source 27. As described above, blade body 12 is provided along convexly arcuate distal edge 22 and at least one of longitudinal edges 18, 20 with a continuous array of teeth including teeth 28 along distal edge 22 and teeth 30, 32 along longitudinal edges 30, 32. Teeth 28 exhibit a first inter-tooth separation or pitch TP1 and teeth 30 and/or 32 has a second inter-tooth separation or pitch TP2 which may be different from inter-tooth separation or pitch TP1.

[0037] In a preferred embodiment, inter-tooth separation or pitch TP1 is uniform among teeth 28, while inter-tooth separation or pitch TP2 is uniform among teeth 30 and/or 32. Inter-tooth separation or pitch TP1 is smaller than inter-tooth separation or pitch TP2, where the teeth of the continuous array of teeth are all isometrically triangular and bear a common angle between opposing edges (a1=a2, exemplarily 60°). Alternatively, one might vary the manufacture, particularly the size of angles a1 and a2, so that pitches TP1 and TP2 are the same.

[0038] Ultrasonic tool or probe 10 enables a finer control of ablation in spinal surgery by reducing the action of the probe on tissues distal of blade body 12. The shorter tooth length TL1 renders arcuate edge 22 less aggressive, reducing the distal cutting action in relative to the rapidity of ultrasonic cutting along longitudinal edges 18 and 20.

[0039] Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. For instance, the pitch and the tooth length (or depth or height) may gradually vary from characteristic values along edges 30 and 32 to different characteristic values along leading or distal edge 22. Alternatively, as indicated schematically in FIG. 7, the change may occur in a single step at a first given point between edges 18 and 22 and at another demarcated point between edges 20 and 22. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.