TISSUE ABLATING LASER DEVICE AND METHOD OF ABLATING A TISSUE

Abstract

A tissue ablating laser device (100) comprises a laser source (110) configured to generate a base laser beam (140) and a beam shaping optics (120) configured to receive the base laser beam (140) and to transform the base laser beam (140) to an emitting laser beam (143). The beam shaping optics (120) further is configured to focus the base laser beam (140) such that the emitting laser beam (143) has a focusing angle (142) of about 10° or less.

Claims

1.-26. (canceled)

27. A tissue ablating laser device comprising: a laser source configured to generate a base laser beam; and a beam shaping optics configured to receive the base laser beam and to transform the base laser beam to an emitting laser beam, wherein the beam shaping optics is configured to focus the base laser beam such that the emitting laser beam has a focusing angle of about 10° or less, of about 5° or less, or of about 3° or less.

28. The tissue ablating laser device of claim 27, wherein the focusing angle is defined by a direction of an outermost ray of the emitting laser beam and a direction of a propagation path of the emitting laser beam.

29. The tissue ablating laser device of claim 28, wherein the direction of the propagation path of the emitting laser beam corresponds to a direction of a central ray of the emitting laser beam.

30. The tissue ablating laser device of claim 27, comprising a wetting equipment configured to wet the tissue to be ablated by the emitting laser beam, wherein the wetting equipment preferably is configured to wet a cut generated in the tissue by the emitting laser beam.

31. The tissue ablating laser device of claim 30, wherein the wetting equipment has a spray nozzle configured to generate a liquid spray to the tissue to be ablated by the emitting laser beam.

32. The tissue ablating laser device of claim 27, wherein the laser source is configured to generate the base laser beam with a wavelength in a range of about 2.5 micrometer to about 3.5 micrometer, or of about 2′940 nanometer.

33. The tissue ablating laser device of claim 27, wherein the laser source is configured to generate the base laser beam as a pulsed laser beam.

34. The tissue ablating laser device of claim 33, wherein the laser source is configured to generate the pulsed base laser beam at a frequency in a range of about 1 to about 100 Hertz or in a range of about 10 to about 30 Hertz, and/or pulses of the pulsed base laser beam having a temporal width in a range of about 5 microseconds to about 300 microseconds, in a range of about 10 microseconds to about 150 microseconds, or in a range of about 50 microseconds to about 120 microseconds.

35. The tissue ablating laser device of claim 27, wherein the beam shaping optics is configured to generate the emitting laser beam with a focal length of more than about 4 cm, wherein the focal length of the emitting laser beam preferably is less than about 25 cm or less than about 20 cm.

36. The tissue ablating laser device of claim 27 being configured to be applied as an osteotome.

37. The tissue ablating laser device of claim 27 configured such that the emitting laser beam has a beam quality factor M squared of about 15 or less or of about 10 or less.

38. A method of ablating a tissue such as a human or animal hard tissue, comprising: generating a focused emitting laser beam; and directing the focused emitting laser beam to a surface of the tissue such that an internal incident angle of the emitting laser beam in relation to the tissue is about 10° or less, preferably about 5° or less and more preferably about 3° or less.

39. The method of claim 38, wherein the internal incident angle is defined by a direction of an outermost ray of the emitting laser beam and a sidewall of a cut in the tissue.

40. The method of claim 38, comprising a step of wetting the tissue to be ablated by the emitting laser beam.

41. The method of claim 40, wherein wetting the tissue to be ablated by the emitting laser beam comprises wetting the sidewall of the cut in the tissue.

42. The method of claim 40, wherein a liquid is sprayed to the tissue to be ablated by the emitting laser beam.

43. The method of claim 38, wherein the emitting laser beam is generated at a wavelength in a range of about 2.5 micrometer to about 3.5 micrometer, or of about 2′940 nanometer.

44. The method of claim 38, wherein the emitting laser beam is generated as a pulsed laser beam, wherein the emitting base laser beam preferably is pulsed at a frequency in a range of about 1 to about 100 Hertz or in a range of about 10 to about 30 Hertz.

45. The method of claim 44, wherein pulses of the pulsed base laser beam have a temporal width in a range of about 5 microseconds to about 300 microseconds, in a range of about 10 microseconds to about 150 microseconds, or in a range of about 50 microseconds to about 120 microseconds.

46. The method of claim 38, wherein the emitting laser beam is generated with a focal length of more than about 4 cm, wherein the focal length of the emitting laser beam preferably is less than about 25 cm or less than about 20 cm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The tissue ablating laser device according to the invention and the method according to the invention are described in more detail herein below by way of an exemplary embodiment and with reference to the attached drawings, in which:

[0062] FIG. 1 shows a schematic view of a first embodiment of a tissue ablating laser device according to the invention;

[0063] FIG. 2 shows a schematic view of a second embodiment of a tissue ablating laser device according to the invention; and

[0064] FIG. 3 shows a graph of fractions of intensity at a bottom of a cut depending on varying internal incident angles.

DESCRIPTION OF EMBODIMENTS

[0065] In the following description certain terms may be used for reasons of convenience and are not intended to limit the invention. The terms “right”, “left”, “up”, “down”, “under” and “above” refer to directions in the figures. The terminology comprises the explicitly mentioned terms as well as their derivations and terms with a similar meaning. Also, spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like, may be used to describe one element's or feature's relationship to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass different positions and orientations of the devices in use or operation in addition to the position and orientation shown in the figures. For example, if a device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be “above” or “over” the other elements or features. Thus, the exemplary term “below” can encompass both positions and orientations of above and below. The devices may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein interpreted accordingly. Likewise, descriptions of movement along and around various axes include various special device positions and orientations.

[0066] To avoid repetition in the figures and the descriptions of the various aspects and illustrative embodiments, it should be understood that many features are common to many aspects and embodiments. Omission of an aspect from a description or figure does not imply that the aspect is missing from embodiments that incorporate that aspect. Instead, the aspect may have been omitted for clarity and to avoid prolix description. In this context, the following applies to the rest of this description: If, in order to clarify the drawings, a figure contains reference signs which are not explained in the directly associated part of the description, then it is referred to previous or following description sections. Further, for reason of lucidity, if in a drawing not all features of a part are provided with reference signs it is referred to other drawings showing the same part. Like numbers in two or more figures represent the same or similar elements.

[0067] FIG. 1 shows a first embodiment of a tissue ablating laser device 100 operated in accordance to apply an embodiment of a method according to the invention. The tissue ablating laser device 100 comprises a laser source 110 and a beam shaping optics 120. The laser source 110 is an Er:YAG laser having an emission line of 2.96 μm and generating a pulsed base laser beam 140 at a frequency of about 20 Hertz and with a temporal width of about 80 μs. The base laser beam 140 starts with an initial diameter 144 and widens at a diverging angle 141.

[0068] The beam shaping optics 120 comprises a convex focusing lens 121. The laser source 110 and the focusing lens 121 are positioned and oriented such that the base laser beam 140 is received by a left hand entry side of the lens 121. The lens 121 transforms the laser beam and emits it in form of an emitting laser beam 143 from a right hand side along a z-axis which corresponds to a propagation path or propagation direction.

[0069] The lens 121 focuses the base laser beam 140 such that the emitting laser beam 143 has a focal point 150 at a focal length of 15 cm. Moreover, the lens 121 shapes the emitting laser beam to have a focusing angle 142 of 6°. The focusing angle 142 is defined by a direction of an outermost ray 145 of the emitting laser beam 143 and the direction of the propagation path of the emitting laser beam 143, i.e. the z-axis or the direction of a central ray 147.

[0070] The tissue ablating laser device 100 further comprises a spray nozzle 151 as wetting equipment. The spray nozzle 151 is configured to generate a liquid spray 152 wherein the liquid particularly is an aqueous solution.

[0071] In operation of the tissue ablating laser device 100 to embody the method according to the invention, the tissue ablating laser device 100 is positioned at a distance of about 12 cm to a bone 131 as tissue to be ablated. More specifically, the tissue ablating laser device 100 is oriented such that the emitting laser beam 143 and the spray 152 are directed to a location of the bone 131 to be ablated. Thereby, the emitting laser beam 143 generates a cut 130 which increases in depth 191 while the emitting laser beam 143 is provided. The cut 131 has a diameter 190 defined by an energy density (ED) or flux of the emitting laser beam 143.

[0072] The spray 152 creates an aqueous film 132 inside the cut 130, wherein sidewalls 180 and a bottom 181 of the cut 130 are covered by the aqueous film 132. Since the emitting laser beam 143 has the focusing angle 142 of 6°, i.e. below 10°, light or rays of the emitting laser beam 143 strikes the sidewalls 180 of the cut 130 at a comparably sharp angle. This effectuates that a comparably large extent of the light of the emitting laser beam 143 is reflected at the sidewalls 180 such that a considerable portion advances to the bottom 181 of the cut 130. Like this, the bottom 181 is ablated and a comparably large depth such as 4 cm or more can be cut into the bone 131.

[0073] Thus, by means of the correctly positioned and oriented tissue ablating laser device 100 the focused emitting laser beam 143 is generated and directed to an outer surface of the bone 131 such at an external incident or initial angle 146 towards an outside plane of the surface of the bone 131 of about 94°. When advancing ablation, the cut 130 is created. Since the emitting laser beam 143 is directed orthogonal to the outer surface of the bone 131, the sidewalls 180 extend at about 90° from the outer surface of the bone 131. Thereby, the emitting laser beam 143 hits the sidewalls 180 at an internal incident angle 148 of about 6°. The internal incident angle 148 is defined by a direction of an outermost ray 145 of the emitting laser beam 143 and the sidewall 180 of the cut 130 in the bone.

[0074] In FIG. 2 a second embodiment of a tissue ablating laser device 100 is shown, which is widely identically designed and operated as the first tissue ablating laser device 100 of FIG. 1. The only difference is that the ablating laser device 100 is equipped with a different beam shaping optics 120. In particular, the beam shaping optics 120 has a focusing lens 121 and, in addition, a collimating lens 122. The collimation lens 122 is positioned upstream of the base laser beam 140 relative to the focusing lens 121. More specifically, the collimating lens 122 receives the base laser beam 140 generated by the laser source 110, collimates the light and provides the collimated beam to the focusing lens 121. The focusing lens then focuses the light and provides the emitting laser beam 143 as described above.

[0075] FIG. 3 shows a graph of a fraction in percent of beam intensity or power of the emitting laser beam 143 reaching the bottom 181 of the cut 130 generated in the bone 131. The axis of ordinates represents a percentage of the fraction of the beam intensity of the emitting laser beam 143 at the bottom 181 of the cut 130. The cut 130 is a hole having a depth of 4 cm and a diameter of 1 cm. The axis of abscissas represents the internal incident angle 148 in degrees. The emitting laser beam 143 has a wavelength A of 2,96 μm and a diameter of 1.3 mm.

[0076] As can be seen in FIG. 3, when providing the emitting laser beam 143 particularly suitable for cutting bone, the fraction of the intensity at the bottom 181 of the 4 cm deep cut 130 in the bone 131 still is more than 50%, when the internal incident angle is 10°. Such cut depth is sufficient for cutting most of human bones. Thus, since the fraction of the intensity is more than 50% the bone 131 can still be efficiently cut even at this comparably high depth.

[0077] However, as can be seen in the graph of FIG. 3, the fraction of the intensity at the bottom 181 of the cut rapidly increases when lowering the internal incident angle 148 below 10°. Thus, by a comparably small adaptation of the internal incident angle 148 a considerable increase of ablation efficiency can be achieved. For example, by lowering the internal incident angle 148 to about 5° about 80% of the emitting laser beam intensity arrives the bottom of the cut 130. Or, at an internal incident angle of about 3° even about 90% of the emitting laser beam intensity can be provided to the bottom of the cut 130.

[0078] This description and the accompanying drawings that illustrate aspects and embodiments of the present invention should not be taken as limiting-the claims defining the protected invention. In other words, while the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of this description and the claims. In some instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the invention. Thus, it will be understood that changes and modifications may be made by those of ordinary skill within the scope and spirit of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below.

[0079] The disclosure also covers all further features shown in the Figs. individually although they may not have been described in the afore or following description. Also, single alternatives of the embodiments described in the figures and the description and single alternatives of features thereof can be disclaimed from the subject matter of the invention or from disclosed subject matter. The disclosure comprises subject matter consisting of the features defined in the claims or the exemplary embodiments as well as subject matter comprising said features.

[0080] Furthermore, in the claims the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single unit or step may fulfil the functions of several features recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The terms “essentially”, “about”, “approximately” and the like in connection with an attribute or a value particularly also define exactly the attribute or exactly the value, respectively. The term “about” in the context of a given numerate value or range refers to a value or range that is, e.g., within 20%, within 10%, within 5%, or within 2% of the given value or range. Components described as coupled or connected may be electrically or mechanically directly coupled, or they may be indirectly coupled via one or more intermediate components. Any reference signs in the claims should not be construed as limiting the scope.