WO2000064358A2

WO2000064358A2 - Surgical waveguide output configurations

Info

Publication number: WO2000064358A2
Application number: PCT/GB2000/001580
Authority: WO
Inventors: Michael John Radley Young; Stephen Michael Radley Young
Original assignee: Michael John Radley Young; Stephen Michael Radley Young
Priority date: 1999-04-21
Filing date: 2000-04-20
Publication date: 2000-11-02
Also published as: WO2000064358A3; GB2350567B; GB2350567A; GB0009678D0; AU4420100A

Abstract

The waveguide output for an ultrasonically vibratable cutting/coagulating tool comprises a surface having a plurality of, usually at least three, longitudinally extending ripples. The effective surface area of the output is thereby increased. A central one of the ripples is comparatively sharp edged. The ripples may be disposed, in profile, along one or more chords of or along an arc of a circle substantially coaxial with the waveguide.

Description

IMPROVED WAVEGUIDE OUTPUT CONFIGURATIONS

The present invention relates to improved waveguide output configurations. More particularly, but not exclusively, it relates to improved waveguide output configurations for torsionally vibratable ultrasonic cutting and coagulating tools.

Such tools are known from British Patent number 2333709B and from our co-pending International Patent Application number PCT/GB99/00162.

The above identified patent and application describe a surgical tool comprising means to generate ultrasonic torsional mode vibrations, a waveguide operatively connected at a

proximal end to said generating means and extending a distance therefrom of nλχ/2 (where

λr is the wavelength of ultrasonic vibration in the material of the waveguide) to a distal end

provided with cutting and/or coagulating means. A number of configurations of the waveguide output or of a jaw which cooperates therewith are discussed.

It has now been found that further improvements in the tools described may be made by choosing novel appropriately shaped waveguide outputs. It is an object of the present invention to provide such improved configurations for waveguide outputs.

According to a first aspect of the present invention, there is provided a waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises a surface having a plurality of longitudinally extending ripples whereby the effective surface area of the output is increased.

The term "ripple" may be taken to mean a portion of the surface of the tool which extends beyond the normal plane of the surface and has a generally rounded form in cross-section.

In some cases, two such ripples may be provided, but it is usually preferred that at least three are provided.

Preferably each of said ripples is based on a hemi-cylinder.

Alternatively the ripple effect may comprise, in profile, a sinusoidally curved surface.

In a further embodiment, at least one, preferably a central one of said ripples is comparatively sharp edged.

The ripples may be disposed, in profile, along one or more chords of a circle substantially coaxial with the waveguide. Alternatively, the ripples may be disposed, in profile, along an arc of a circle substantially coaxial with the waveguide.

According to a second aspect of the present invention, there is provided a waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises a substantially oval or elliptically profiled output cooperable with a substantially planar static jaw.

The orientation of said elliptically profiled waveguide output relative to that of said jaw may be selected to be at either one of two dispositions, each orthogonal to the other.

In this case, when the major axis of the elliptically profiled waveguide output is aligned substantially parallel to the jaw, coagulation of intervening tissue may be expected.

On the other hand, when the minor axis of the elliptically profiled waveguide output is aligned substantially parallel to the jaw, improved cutting of intervening tissue may be expected.

According to a third aspect of the present invention, there is provided a waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises a square cut groove extending longitudinally along at least part of the length of said output.

Preferably, a substantially rectangular jaw is adapted to cooperate at least partially within said square cut groove.

Alternatively, a substantially triangular shaped jaw may be provided. According to a fourth aspect of the present invention there is provided a waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises at least one substantially planar member having a proximally facing hook shaped or re-entrant cutting edge.

There may be two such edges, one diametrically opposed to the other.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which:-

Figure 1 is a cross-sectional view of a waveguide output having a rippled profile; Figure 2 is a cross-sectional view of a waveguide output having an improved rippled profile;

Figure 3 is a cross-sectional view of a waveguide output having a rippled profile around part of the periphery of the output;

Figure 4 is a cross-sectional view of a waveguide output in which a ripple- profiled area is available for contact with a flat jaw;

Figure 5 is a cross-sectional view of a waveguide output having a generally V- shaped profile- Figure 6 is a cross-sectional view of a waveguide output similar to that shown in Figure 5 but having a more rounded cross-section;

Figure 7 is a cross-sectional view of a waveguide output having a ripple profile area in which the central ripple is sharp and projects to the circumference of the waveguide, Figures 8A and 8B show a further embodiment in which an elliptical waveguide output may be changed in orientation,

Figure 9 is a cross-sectional view of a triangular profile waveguide output adapted for coagulation,

Figure 10 is a cross-sectional view of a triangular profile waveguide output adapted for cutting,

Figures 11A and 11B are cross-sectional views of a waveguide output having a square slot along its length and alternative jaw shapes for cooperating therewith.

Figures 12A and 12B show triangular jaw shapes for use with the square slot of

Figure 11 A,

Figures 13A and 13B are cross-sectional views showing a key profile jaw adapted for insertion within a keyhole profile slot of the waveguide output,

Figure 14 is a side elevation of a hook-type output;

Figure 15 is a plan view of a hook-type output as shown in Figure 14, in which the output has a double hook blade, and

Figure 16 is a plan view of a hook-type output with a single hook blade

Referring now to the drawings there are shown various alternative configurations of torsional waveguide output

Torsional mode vibration provides concentric motion about the axis of the waveguide and a vibrating blade Sections of the blade non-parallel with the motion provide vibrating faces capable of imparting energy directly into tissue brought to bear on such a face rather than cause friction as in conventional, parallel motion devices The face may be normal to the motion or at an intermediate angle thereto, i e any angle between 1° - 179°, although 60° -

120° is preferred, and 90° may be most advantageous

Tissue is trapped between the closing blades and the speed and ease of cutting and/or blood coagulation will depend on the mode and amplitude of the vibration and the geometry of the blades, designed to utilise the torsional mode of the vibrating blade

Figures 1 to 7 show variations in configuration of a waveguide output adapted to maximise the magnitude of the area of the waveguide output having a component perpendicular to the direction of torsional displacement

In Figure 1, there is shown an output having a rippled profile extending along two chords which make between them an angle ≥ 90°

The ripples are shown as semicircular arcs with the radius of each arc and the length of the chord in simple numerical relationship In the example shown

lc - 8 la where l_c is the length of each chord and l_a is the radius of each arc, and therefore the ratio of total rippled area A_R between A and A' in this example and the "flat" area A_F is

A_R -= π/₂ A_F In this case, a central lobe of the ripples extends out to the maximum waveguide radius and will vibrate with maximum torsional amplitude Figure 2 shows a more robust and/or fatigue resistant variation of the embodiment of Figure

1 produced by smoothing of the ripple formation towards the central lobe

Figure 3 is a variant with a ripple profile along a major arc coaxial with the waveguide and inset enough to allow a coaxial jaw to connect within the overall diameter The ripples are shown as semicircular arcs each centred on the major arc with the radius of each arc in simple numerical relationship with the radius of the major arc, with the locus of all the minor arcs making up the ripple formation

In this example

Therefore, the ratio of the total rippled surface area A_R between C and C¹ to the notional surface area Ac, 1 e the area of a periphery at a mean radius is A_R -S 2 Ac Hence, the available area of the output may be approximately doubled by use of a rippled surface

Figure 4 shows a substantially flat jaw cooperable with a large rippled area of the waveguide output with the ripples arranged along a chord parallel to the jaw, of the otherwise circular output Hence, again there is an increased contact area, permitting improved coagulation of tissue between the jaw and the rippled zone

Figure 5 shows a section through the output end of a waveguide which contains a 90° V- shaped groove down to the axis of the waveguide and a corresponding N-shaped blade on the opposite external side of the waveguide A variant of this is shown in Figure 6 where the profile is rounded to a more shallow external blade Figure 7 is a variant of the embodiment shown in Figure 4, but one in which the central blade is sharp and projects to the circumference of the waveguide It is separated from the more rounded side blades by two grooves. As tissue is coagulated in the two grooves, it is severed by the central blade, which acts to separate the tissue with its side to side torsional motion

Referring to Figure 9, there is shown an arrangement adapted principally for coagulation by virtue of minimal vibrational amplitude at the apex of the triangular output. Contrary to our previous disclosures in which a female waveguide profile cooperated with a male jaw, the present aspect of the invention envisages cooperation between a male N-shaped waveguide profile and a female N-shaped groove in the static jaw.

Figure 10 shows a variant in which an apex of a male N-shaped waveguide profile operates at maximum amplitude within a female static jaw, thereby improving cutting. It also gives coagulation over a large area, by virtue of the surface area normal to the direction of vibration.

Referring now to Figures 11 and 12, there is shown a waveguide output which is provided along a portion of its length with a square cut channel The static jaw may also have a rectangular profile adapted to fit closely within the rectangular cross-section slot of the waveguide output. In Figure 11 A, normal coupling within the square slot allows a large contact area, suitable for coagulation. However, the close fit allows cutting, especially in the corners of the jaw where there is maximum torsional amplitude Figure 1 IB shows a variation giving increased coagulation by shear coupling over the surface of the output outside the slot. In Figures 12A and 12B, the same square cut channel is used, but the static jaw has a triangular profile. This allows more gentle coagulation to be provided within the square slot due to normal coupling over the tapered jaw section The jaw of Figure 12B further provides shear coupling over the outer surface, in similar manner to the jaw of Figure 1 IB

Referring now to Figure 8, there is shown an embodiment in which the jaw is substantially flat and the waveguide output has an elliptical cross-section The orientation of the waveguide output in relation to the flat jaw is variable through 90°, as indicated in Figures 8A and 8B. With the disposition shown in Figure 8A, there is enabled a large degree of coagulation of tissue between the comparatively large, gently curved, area of the waveguide output.

However, when the waveguide output is oriented orthogonally, there is a large degree of cutting of tissue due to the maximum amplitude shear at the ends of the major axis of the elliptical profile waveguide output

Figure 13 shows an embodiment in which the waveguide output has a slot of width L, leading to a cylindrical chamber within the waveguide In this case, the jaw has a similar keyhole profile, although with the diameter of the cylindrical insert being less than L This arrangement gives coagulation over the large inner surface area and between the parallel faces where there is maximum vibrational amplitude The cutting effectiveness increases as 1 approaches L, where 1 is the thickness of the connecting piece of the jaw Figure 14 is a side elevation of a "hook-type" output Such an output is substantially planar and is adapted to slide between the sheets of tissue and collect individual vessels between The hooked or re-entrant shape of the cutting edge allows the tool to collect individual vessels, and coagulate and cut them as the head is moved outwardly No jaw is needed to cooperate with such an output

Figures 15 and 16 show plan views of two variants of the hook-shaped output of Figure 14 That shown in Figure 15 has two diametrically opposed hook blades, while that shown in Figure 16 has a single hook blade As may be seen from Figure 16, a vessel is caught by the rearward facing edge of the hooked blade and as it is pulled proximally, the vessel is cauterised and cut by virtue of the torsional energy supplied to the blade.

As stated above, the waveguide output systems described herein are ideally adapted for use with torsionally vibratable ultrasonic haemostatic cutting tools as described in more detail in our co-pending applications.

Claims

1 A waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises a surface having a plurality of longitudinally extending ripples whereby the effective surface area of the output is increased

2 A waveguide output as claimed in claim 1, wherein two such ripples are provided

3 A waveguide output as claimed in claim 2, wherein at least three such ripples are provided

4 A waveguide output as claimed in any one of the preceding claims, wherein each of said ripples is based on a hemi-cylindrical profile

5 A waveguide output as claimed in any one of claims 1 to 3, wherein the ripple effect may comprise, in profile, a sinusoidally curved surface

6 A waveguide output as claimed in any one of the preceding claims, wherein at least one, preferably a central one, of said ripples is comparatively sharp edged

7 A waveguide output as claimed in any one of the preceding claims, wherein the ripples are disposed, in profile, along one or more chords of a circle substantially coaxial with the waveguide

A waveguide output as claimed in any one of claims 1 to 6, wherein the ripples are disposed, in profile, along an arc of a circle substantially coaxial with the waveguide

A waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises a substantially oval or elliptically profiled output cooperable with a substantially planar static jaw

A waveguide output as claimed in claim 9, wherein the orientation of said elliptically profiled waveguide output relative to that of said jaw is selectable to be at either one of two dispositions, each orthogonal to the other

A waveguide output as claimed in claim 10, wherein the tool is adapted to cause mainly coagulation of intervening tissue when the major axis of the elliptically profiled waveguide output is aligned substantially parallel to the jaw

A waveguide output as claimed in claim 10, wherein the tool is adapted for improved cutting of intervening tissue when the minor axis of the elliptically profiled waveguide output is aligned substantially parallel to the jaw

A waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises a square cut groove extending longitudinally along at least part of the length of said output

A waveguide output as claimed in claim 13, wherein a substantially rectangular jaw is adapted to cooperate at least partially within said square cut groove

15. A waveguide output as claimed in claim 13, wherein a substantially triangular-shaped jaw is adapted to cooperate at least partially within said square cut groove.

16. A waveguide output for an ultrasonically vibratable cutting/coagulating tool which comprises at least one substantially planar member having a proximally facing hook shaped or re-entrant cutting edge.

17. A waveguide output as claimed in claim 16, wherein there are provided two such edges, one diametrically opposed to the other.