WO2003009767A1

WO2003009767A1 - Cutting tool and method

Info

Publication number: WO2003009767A1
Application number: PCT/IB2002/002816
Authority: WO
Inventors: Evert Pieter Houwman; Herman Philip Godfried
Original assignee: Element Six B.V.; Gilson, David, Grant
Priority date: 2001-07-20
Filing date: 2002-07-19
Publication date: 2003-02-06

Abstract

A cutting tool, particularly one for a surgical application. The cutting tool comprises a body such as a handle and a cutting component (10) having a cutting zone (14) mounted in or on the body, means adapted to cause incident radiation (22) to enter the cutting component (10) and pass through the cutting zone (16, 18, 20) and means to separate returning radiation (26) passing back into the cutting tool (10) from the incident radiation (22).

Description

CUTTING TOOL AND METHOD

BACKGROUND OF THE INVENTION

This invention relates to a cutting tool and a method for using such a tool.

In general surgery a surgeon very often excises tissue from a patient which needs to be examined by a pathologist. Examples are excisions of carcinoma where the pathologist needs to determine whether or not all of the carcinoma has been excised. Histological examination of the tissue usually takes place "off-line". That is the pathologist examines the tissue after the operation has taken place and the results may not be in for hours or days. In some cases it is crucial that all of the diseased tissue that should be excised, is indeed removed, while at the same time healthy tissue should be as little affected as possible (e.g. brain tumour surgery). In extreme cases this could lead to repeated surgery when it is found after the operation that not all of the diseased tissue was excised, e.g. when the edges of the excised material were not all clean and free of non-healthy tissue. This is not an academic issue: according to one study (New Scientist 2001 , Jan. 6, page 5), in nearly 25% of operations to remove breast cancer surgeons miss some cancerous tissue and the operation may have to be repeated.

Recently experiments have been carried out with probes that can discern between the different types of cells. In these experiments Bakker Schut et. al (In vivo Detection of Dysplastic Tissue by Raman Spectroscopy, TC Bakker Schut, MJH Witjes, HJCM Sterenborg, OC Speelman, JLN Roodenburg, ET Marple, HA Bruining, GJ Puppels, Analytical Chemistry, 2000, Vol 72, Iss 24, pp 6010-6018) used a fibre optic probe about a millimetre in diameter to guide light to the tissue and then guide Raman scattered light back to a spectrometer for analysis. Raman scattering is a light scattering process in which the scattered light has a frequency spectrum, which is shifted from the incident light spectrum. The amount, by which it is shifted, is characteristic of the material or system off which it was scattered. Thus, it is possible to differentiate between healthy and carcinogenic tissue by examining the Raman spectra. Based on the spectra the surgeon can then decide to continue excising or not.

In separate articles by Anil Ananthaswamy in the New Scientist of January 6 2001 (page 5) and by Fiona Harvey in the Financial Times of February 21, 2001 a so-called smart scalpel is described. However in these articles the scalpel is still an intrinsically "dumb" tool with a separate "smart" probe. This combination has the disadvantage that the probe does not actually measure at the same position where the blade is cutting and accurate re-positioning needs to be done in order to ensure that the scalpel is cutting where the probe has indicated that cutting is necessary. Thus, the surgeon has to interrupt the cutting procedure in order to make the assessment whether or not to continue cutting. Also the probe and blade assembly will have a larger size (cross- section) than just the blade itself.

US 4,627,435 discloses a surgical knife which includes a handle supporting a diamond blade. A laser is optically coupled to a bundle of optical fibres to the blade. The arrangement enables the blade to cauterise tissue being incised by the knife. There is no disclosure or suggestion that the surgical knife is associated with means to analyse or examine tissue or material being cut.

WO 01/00100 discloses a cutting blade for a surgical instrument which includes means for passing laser radiation through the blade. The blade is not designed for, or capable of, being used to analyse tissue or material being cut. SUMMARY OF THE INVENTION

According to the present invention, a method of cutting a material includes the steps of providing a cutting tool comprising a body, generally a hand-grippable body, and a cutting component having a cutting zone mounted in or on the body, using the cutting component of the tool to cut a region of the material, transmitting incident radiation at the region being cut during, after or before cutting, capturing in the component at least some of the radiation which is reflected or scattered by the material, and analysing the captured radiation.

Thus, in the method of the invention, the incident radiation is transmitted at the region being cut. Preferably, the incident radiation is transmitted through the cutting component and means are provided, preferably in the cutting tool, to separate the captured radiation from the incident radiation.

According to another aspect of the invention, there is provided a cutting tool comprising a body, generally a hand-grippable body, and a cutting component having a cutting zone mounted in or on the body, means adapted to cause incident radiation to enter the cutting component and pass through the cutting zone and means to separate returning radiation passing back into the cutting component from the incident radiation. The returning radiation will generally be passed to a suitable device or means for analysis.

The radiation may be radiation adapted to perform a function such as a diagnostic or detection function in the material to be cut. The invention has particular application to cutting tools for surgical applications where the functional radiation may be designed to detect or diagnose the nature of or characteristics of tissue being cut. The incident radiation may be any suitable radiation such as laser radiation. The returning radiation may be that resulting from spontaneous or stimulated Raman scattering, laser induced fluorescence (LIF), attenuated total reflection (ATR) and other types of fluorescence, phosphorescence, luminescence or scattering processes.

In one particular form of the invention, the incident radiation is light suitable for obtaining spectroscopic information of tissue being cut. The light will pass through the cutting component and the returning light can be collected through the same component. The returning light will be separated from the incident light and passed on for analysis, e.g. Raman spectrum analysis.

The cutting tool and method of the invention have particular application to surgery such as general surgery, oncology, obstetrics/gynaecology, ear, nose, throat surgery or neurosurgery. A further application for the cutting tool and method of the invention is in microscopy such as is used in microtomes or ultra-microtomes for pathology and process control.

The cutting component must be made of a material which is transparent to the radiation. Examples of suitable materials, which have sufficient hardness, are oxides such as sapphire, aluminium garnets, transition metal oxides (e.g. zirconia or yttria), other garnets, orthosilicates, glass and suitable synthetic or natural hard gemstone materials. The preferred material is diamond, particularly CVD diamond, because of its biocompatibility, its hardness, its ability to have a keen cutting edge produced on it, its transparency to a wide range of radiation from ultraviolet to far-infrared, its high abrasion resistance and high thermal conductivity. The cutting tool can also be made in such a way that the incident radiation can be used to cauterise blood and or kill living cells or destroy dead cells. This radiation may not have the same nature as the radiation that is used for analysing returning radiation for diagnostics, e.g., one may use CO2 laser at a wavelength of 10.6μm for the purpose of cauterising, while using a different wavelength for diagnostics. The radiation may also be X-ray. Apart from light radiation, other waves such as ultrasonic waves may also be used.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 to 3 are schematic perspective views of three embodiments of cutting components for cutting tools of the invention; and Figures 4 to 6 are schematic views of the embodiments of Figure 2 with different means for separating returning radiation from incident radiation.

DESCRIPTION OF EMBODIMENTS

In the cutting tool of the invention, incident radiation passes through the cutting component and directly into the material, at the point or area which is being cut. Physical processes such as scattering and reflection of the incident radiation will take place giving rise to returning radiation. Some of that returning radiation will pass back into the cutting component where it will pass on to means to separate the returning radiation from the incident radiation. Such means are well known in the art. Examples of such means are: 1. Separate waveguides, such as optical fibres, for the transmission of incident radiation and the transmission of returning radiation.

2. A wavelength dependent filter or beam splitter.

3. A polarisation dependent component such as a polariser or a waveplate.

4. Any combination of 1 to 3.

The returning radiation is then passed on for analysis, e.g. by a spectrometer or a filter in combination with a photo-detector.

Various known optical components may be used in combination with the means for separating the incident radiation from the returning radiation. Examples of such optical components are lenses, mirrors, prisms, filters, gratings and polarisation dependent components. These components may be made of materials known in the art such as glass, sapphire or reflecting metals.

The cutting zone of the cutting component may be provided with one or more coatings to enhance the transmission of radiation into or from the cutting zone, or such coatings may enhance the transmission or reflection of returning radiation into the cutting zone. The waveplates or filters may also be provided with suitable coatings to enhance the separation of the returning radiation from the incident radiation, e.g. to enhance the reflection of returning radiation by the waveplate or filter.

The cutting component may be of any suitable shape. Embodiments of suitable cutting components are illustrated schematically by Figures 1 to 3. Referring first to Figure 1 , the insert 10 is spear-shaped having a back or rear side 12 and a cutting end 14. The cutting end 14 has cutting edges 16, 18 and a cutting point 20. Incident radiation 22, for example laser radiation, passes into the component from optical fibre 24 through the back side 12. Depending on the shape of the back side 12, the radiation may be directed to exit only near the point 20 of the cutting component 10, or over the cutting point 20 and the cutting edges 16, 18. Some of the radiation which returns from the material being cut may be collected near the point 20 or over the extended area of point 20 and cutting edges 16, 18. That returning radiation 26 passes back up the optical fibre 24 where means, e.g. a beam splitter, are provided to separate the radiation 26 from the incident radiation 22.

The cutting component 30 of Figure 2 has a chisel-shaped cutting edge 32. Incident radiation 34 from optical fibre 36 may be directed to pass into the component through rear end 40 and through the chisel-shaped cutting edge 32. Some of the returning radiation 38 collected at the cutting edge 32 passes back through the component 30, into the optical fibre 36 and through a known beam splitter or other device which separates the returning radiation 38 from the incident radiation 34.

A needle-shaped component 50 is illustrated by Figure 3. The component 50 has a sharp needle-like tip 52 which can be used to make holes in material to be cut with minimum damage. Incident radiation 54 from optical fibre 56 is directed to pass through the rear end 58 and then the needle-like tip 52. Some of the returning radiation 60, scattered or reflected by the material, is collected by the same tip. That returning radiation 60 passes back through the component 50, along the optical fibre 56 and through a beam splitter or other device to separate it from the incident radiation 54. As mentioned above, the means to separate the returning radiation from the incident radiation may be any one or more of a number of components known in the art. These components may be coupled with other known optical components to enhance the collection of the radiation or improve its transmission either to the tool or to an analysing device. Examples of such means are illustrated by Figures 4 to 6. In each of these figures, the cutting component 30 of Figure 2 has been used.

Referring first to Figure 4, incident radiation 34 is transmitted through central optical fibre 70. Surrounding fibres 72 are designed to collect and transmit the returning radiation 38.

Referring to Figure 5, incident radiation 34 from fibre 74 passes through a polariser or waveplate 76. The polariser 76 is adapted to reflect returning radiation 38 which passes on to a suitable analysing device. The polariser 76 may be provided with a coating to enhance the reflection of the returning radiation.

Referring to Figure 6, incident radiation 34 from fibre 78 passes through a wavelength dependent filter 80 and into the tool component 30. The returning radiation 38 of different wavelength is reflected by the filter 80 and passes on to a suitable analysing device. The filter 80 may be provided with a coating to enhance the reflection of the returning radiation.

The cutting components described above and illustrated by Figures 1 to 3 may be mounted in hand-grippable bodies or handles, as is well known in the art. The cutting tools thus produced have particular application in the cutting of animal or human tissue in surgery. The polariser 76 and filter 80 may also be mounted in the hand-grippable bodies. The cutting tool of the invention and, in particular the embodiments described above, may be used in a variety of applications. The cutting tool has particular application to the cutting of tissue in a surgical application. Examples of uses and applications of the cutting tool are:

i. The captured radiation or returning radiation may be analysed to determine the depth of the cutting zone of the tool component in the material and/or the speed of penetration of the cutting zone of the tool component into the material.

ii. The cutting tool may be used as a pressure sensor based on blade deformation. The detection of the deformation may, for example, be in an optical signal as a function of the deformation.

iii. Detecting defects in the cutting zone such as chip-out or breakage during use. Again, an optical signal may be used as a function of any such defects.

iv. The cutting tool may include means to pass cauterising radiation through the cutting zone. This cauterising radiation will be separate from the incident radiation. Such radiation will cause blood cauterisation. The captured or returning radiation may be used to detect the level of blood cauterisation.

v. The captured radiation or returning radiation may be analysed to determine the presence of unwanted cells in tissue, for example the presence of bad or dead cells which need to be destroyed. A separate radiation beam may be passed through the blade to destroy such cells.

vi. The recognition and warning of certain chemicals/viruses/anti- viruses in tissue being cut.

When the radiation is laser radiation, a laser diode may be mounted directly on the body of the tool component as the light source.

The cutting tool may include means to pass pulsed RF radiation through an antenna in the cutting component and thereafter into a material being cut. The antenna may be introduced into the cutting component, when it is diamond, by ion implantation.

Claims

A method of cutting a material includes the steps of providing a cutting tool comprising a body and a cutting component having a cutting zone mounted in or on the body, using the cutting component of the tool to cut a region of the material, transmitting incident radiation at the region being cut during, after or before cutting, capturing in the component at least some of the radiation which is reflected or scattered by the material and analysing the captured radiation.

A method according to claim 1 wherein the material being cut is animal or human tissue.

A method according to claim 2 wherein the captured radiation is analysed to diagnose or detect one or more characteristics of the tissue being cut.

A method according to claim 2 or claim 3 wherein radiation suitable to cauterise blood is directed at the region of tissue being cut and the captured radiation is analysed to determine the level of blood cauterisation.

A method according to any one of claims 2 to 4 wherein the captured radiation is analysed to determine the presence of unwanted cells in the tissue.

6. A method according to any one of the preceding claims wherein the captured radiation is analysed to determine the penetration depth of the cutting zone of the tool component into the material.

7. A method according to any one of the preceding claims wherein the captured radiation is analysed to determine the speed of penetration of the cutting zone of the tool component into the material.

8. A method according to any one of the preceding claims wherein the captured radiation is analysed to detect any defects in the cutting zone of the tool component.

9. A method according to any one of the preceding claims wherein the incident radiation passes through the cutting component.

10. A method according to any one of claims 1 to 8 wherein the radiation does not pass through the cutting component and is directed at the region of material being cut.

11. A method according to any one of the preceding claims wherein the material of which the cutting component is made is selected from oxides, garnets, orthosilicates, glass, and synthetic or natural hard gemstone materials.

12. A method according to any one of claims 1 to 10 wherein the cutting component is made of diamond.

13. A method according to claim 12 wherein the diamond is CVD diamond.

14. A cutting tool comprising a body and a cutting component having a cutting zone mounted in or on the body, means adapted to cause incident radiation to enter the cutting component and pass through the cutting zone, and means to separate returning radiation passing back into the cutting component from the incident radiation.

15. A cutting tool according to claim 14 wherein the body is a hand- grippable body.

16. A cutting tool according to claim 14 or claim 15 which is one for a surgical application.

17. A cutting tool according to any one of claims 14 to 16 wherein the cutting component is made of a material selected from oxides, garnets, orthosilicates, glass, and synthetic or natural hard gemstone materials.

18. A cutting tool according to any one of claims 14 to 16 wherein the cutting component is made of diamond.

19. A cutting tool according to claim 18 wherein the diamond is CVD diamond.

20. A cutting tool according to any one of claims 14 to 19 wherein the means to separate returning radiation from incident radiation is a beam splitter.

21. A cutting tool according to claim 20 wherein the beam splitter is a wavelength dependent filter or a polarisation dependent component.

22. A cutting tool according to any one of claims 14 to 19 wherein the means to separate returning radiation from incident radiation is one or more separate waveguides.

23. A cutting tool according to claim 22 wherein the waveguide is an optical fibre.

24. A cutting tool according to any one of claims 14 to 23 wherein a combination of separate waveguides and a wavelength dependent filter is used to separate returning radiation from incident radiation.

25. A cutting tool according to any one of claims 14 to 24 wherein the cutting zone of the cutting component is provided with a coating or coating layers to enhance the transmission of incident radiation therethrough.

26. A cutting tool according to any one of claims 14 to 25 wherein the cutting zone is provided with a coating or coating layers to enhance the transmission of returning radiation into the cutting zone.

27. A method according to claim 1 substantially as herein described with reference to any one of Figures 1 to 6 of the accompanying drawings.

28. A cutting tool according to claim 14 substantially as herein described with reference to any one of Figures 1 to 6 of the accompanying drawings.