WO2009046793A1 - Laser focusing handpiece - Google Patents

Abstract

The invention relates to a laser focusing handpiece for focusing a laser beam emitted from a fiber optic onto a focus by means of an optical arrangement, wherein the ratio of the diameter of the fiber optic to the diameter of the focus indicates the focus factor of the laser focusing handpiece. In order to be able to use the desired application power with acceptable size dimensions, the invention proposes that the optical arrangement be designed such that a focus factor of 1 or less results.

Description

 Laserfokussierhandstück

The invention relates to a laser focusing handpiece with the features of the preamble of claim 1.

Such laser handpieces find z. As in medicine, especially in laser surgery application. Laser surgery offers the advantage over conventional surgery with a steel scalpel, that in addition to the transection of the treated tissue at the same time an extensive coagulation is generated. This is especially in well-perfused tissues such. As internal organs, an advantage. However, a disadvantage of the currently available laser surgery systems on the market is the low power density, which they provide the surgeon. Although this is well suited for superficial treatment, eg. B. of vessels, makes the severing of thicker organs, such as. As the liver, or the separation of a part of it, however, very tedious. On the other hand, more powerful components always have a larger footprint. In particular, the handpiece of such a laser surgery system should not be too large in size, however, to allow the attending physician good handling and thus accurate guidance of the laser beam.

The invention is based on the object of a Laserfokussierhandstück to improve the aforementioned genus to the effect that with acceptable size dimensions, the desired application performance can be used.

This object is achieved with a Laserfokussierhandstück with the features of claim 1.

This offers the advantage that it not only focuses on the energy delivered by the optical fiber, namely the laser beam to a focal point, but also at the same time reinforced. The laser focusing handpiece according to the invention allows focusing of the energy emitted by a large optical fiber diameter to a relatively small focus diameter and thus achieves a focus factor of less than one. That is to say, the energy emitted by the laser focusing handpiece per unit area in the focus increases in relation to the energy emitted per unit area by the optical fiber alone. Depending on the field of application and design of the Laserfokussierhandstücks the focus factor can also lie at about one. However, even this configuration, which provides a one-to-one transmission of the power density of the optical fiber into focus, outperforms conventional laser focusing handpieces.

Advantageously, the optical arrangement can have a plurality of cascaded lenses, which allow the energy emanating from the optical fiber to be focused in such a way that the energy density remains at least equal or increased.

In a favorable embodiment of the invention, the optical arrangement may comprise an aspherical lens. This can replace several or all of the aforementioned spherical lenses and thereby allows a reduction in the dimensions of the Laserfokus- sierhandstücks. The use of aspheric lenses often not only reduces the length but also the diameter of the laser focusing handpiece.

In a variant of the invention, the optical arrangement may have a releasably secured, light-transmitting element at its proximal end facing the focus. As a result, the underlying optical arrangement is protected against contamination.

Conveniently, the translucent element may comprise an optical lens. Thus, this last element closest to the focus of the optical arrangement also contributes to the focusing of the laser beam. This allows a reduction in the dimensions of the optical arrangement.

Further, the optical arrangement may have a numerical aperture in the range of 0.1 to 0.22. This allows a good energy transfer into the focal point and a favorable distance of the focal point of the Laserfokussierhandstück.

In an advantageous embodiment of the invention, the diameter of the optical fiber in the range of 600 to 300 microns. This allows the supply of a sufficient amount of energy and yet ensures handy dimensions of the Laserfokussierhandstücks.

Furthermore, the focus diameter may be in the range of 500 to 50 μm. This allows a good concentration of energy per unit area and at the same time represents a diameter that is easy to handle for the surgeon. Conveniently, the wavelength of the laser beam may be in the range of 1100 to 1400 nm. This ensures good absorption of the laser beam in human or animal tissue.

Furthermore, the Laserfokussierhandstück may have an air flow in its interior. On the one hand, this offers the advantage of integrated cooling. On the other hand, due to the permanent air flow, any particles rising from the operating area are kept away from the optical arrangement.

Advantageously, the air flow can surround the optical arrangement in an annular manner. This ensures efficient cooling of the optical arrangement.

Further, the air flow may have an air pressure of 250 to 550 kPa, preferably 300 to 500 kPa or 475 to 525 kPa, and more preferably about 500 kPa. These pressures have been found to be particularly favorable for the operation of human or animal tissue and allow both good cooling and prevention of fouling of the optical assembly. At the same time an impairment of the tissue to be treated by this pressure range is largely prevented.

In an advantageous embodiment of the invention, the optical arrangement can be mounted in a cap detachably attached to the handpiece. This facilitates the handling, especially the accessibility to the optical arrangement and simplifies the sterilization of the Laserfokussierhandstücks.

Furthermore, the distance of the optical fiber end, from which the laser beam exits to the optical arrangement 25 to 35 mm, preferably 27 to 31 mm, and in particular 28.5 to 29.5 mm. This allows a good, largely lossless coupling of the laser energy in the optical arrangement. Especially good is a distance of 29.1 mm.

Advantageously, the optical arrangement can be designed such that the diverging light beam emerging through the optical fiber end is approximately completely fed into the lens system. This ensures a good focus and allows the highest possible energy density in the focal point.

Furthermore, the optical arrangement can be designed such that at least part of the light beam emerging through the optical fiber end is fed into the lens system. This allows the selective, targeted feeding of a certain proportion of the the optical fiber emitted light energy and thus a good dosage. Furthermore, this allows a further reduction in the outer dimensions of the Laserfokussierhandstücks.

An embodiment of the invention will now be described with reference to the following drawings. Show

1 shows a cross section through an inventive Laserfokussierhandstück and

FIG. 2 shows a detail of FIG. 1, which shows the proximal end of the optical arrangement.

FIG. 1 shows a cross section through a laser focusing handpiece 1. The Laserfokussierhandstück 1 is approximately cylinder-shaped in this embodiment and can be roughly divided into a base part 2 and a head part 3. The base part 2 represents a connection side of the Laserfokussierhandstücks 1 and contains a fluid port 4, to which z. B. a compressed air leading hose 5 can be connected, and a holder 6 for an optical fiber. 7

The fluid connection 4 communicates with a fluid channel 8 in the head part 3 of the laser focusing handpiece 1 and supplies it with a fluid flow. The optical fiber 7 in this embodiment has a diameter of about 600 microns and extends over the holder 6 also in the head part 3 of the Laserfokussierhandstücks 1 inside. There, its proximal end 9 is fixed in a stop 10. However, in other embodiments of the invention, the diameter of the optical fiber 7 may vary. Preferably, this diameter is in a range of 300 to 600 microns.

The head part 3 of the laser focusing handpiece 1 has an optical arrangement 11, which comprises the stop 10 and a lens system 12. The lens system 12 has seven consecutively arranged, optical lenses 12a to g with a diameter of 18 mm. Alternatively, one, several or all of the spherical lenses 12a to g shown here may be replaced by an aspherical lens. The first lens 12a of the lens system 12 is arranged at a distance 13 of about 29 mm, exactly 29.09 mm, to the proximal end 9 of the optical fiber 7.

The stopper 10 is in a surrounding housing 14, z. B. via a thread 15, arranged. D. h., The position of the stopper 10 can be adjusted as required by turning the stopper 10 relative to the housing 14. The housing 14 is in this This embodiment is formed in one piece with the holder 6 for the optical fiber 7 and the fluid end 4. By screwing in or out of the stop 10 in or out of the thread 15, the distance 13 between the lens system 12 and the proximal end 9 of the optical fiber 7 can be regulated in a certain range. The distance 13 is therefore preferably in a range of 10 to 40 mm, preferably 20 to 30 mm.

The lens system 12 is arranged in this embodiment in a sleeve 16 with a socket 17 and screwed by means of this with the housing 14, so that the lens assembly 12 is held between a front proximal end 18 of the housing 14 and the socket 17.

Optionally, on the sleeve 16 at its proximal end facing the focus 26 in the region of the socket 17, a light-transmitting element 25, for. As a glass or a disc made of high quality plastic, are releasably attached, as shown in Figure 2. For reasons of clarity, the covering cap 20 shown in FIG. 1 is not shown in FIG. The reference symbols used in FIG. 2 designate the same parts as in FIG. 1, so that reference is made to the description of FIG. 1 in this regard. The translucent element 25 can be taken in a further sleeve 27, which is up to the sleeve 16 and can be pre-inserted and forms a slight press fit with this, so that the translucent element 25 is frictionally held on the sleeve 16.

Alternatively, the detachable attachment of the sleeve 27 by other common means such. As a thread, etc., take place, which allow a quick and easy removal or replacement of the translucent member 25. However, the translucent element 25 may also be involved in the focusing of the light. Thus, the translucent element 25 z. B. also be the last lens 12 g of the lens system 12. This counteracts undesirable enlargement of the outer dimensions of the laser focusing handpiece 1.

In the exemplary embodiment shown in FIG. 1, the distance 13 and the diameter of the lens system 12 are selected as a function of the numerical aperture of the optical fiber 7 such that the diverging light cone 19 emerging from the proximal end 9 of the optical fiber 7 enters the lens system 12 almost completely , The numerical aperture of the optical fiber 7 is preferably in a range of 0.1 to 0.22. In the embodiment of the invention shown here, it is 0.22. Alternatively, however, the lenses 12a-g of the lens system 12 may be vignetted. This means that the distance 13 and / or the diameter of the lens system 12 are selected so that only a certain portion of the light cone 19 emitted from the proximal end 9 enters the lens system 12.

In the region of the head part 3, a cap 20 is detachably mounted on the housing 14. The cap 20 is approximately cylindrical in this embodiment and connected via a thread 21 to the housing 14. It represents a kind of cladding, or outer skin for the holder 6 and the optical assembly 11, and is flush with the outer skin, or with the surface 22 of the base part 2. Alternatively, the cap 20 may extend over the head part 3 and the base part 2.

The inner diameter of the approximately cylindrical cap 20 is slightly larger than the outer diameter of the housing 14 and the sleeves 16, 27 so that between the housing 14 and the sleeves 16, 27 and the cover 20, an annular gap is formed, which acts as FIu- idkanal 8 and in which the fluid port 4 opens. In the concrete embodiment of the invention described here, the maximum outside diameter predetermined by the housing 14 and the sleeves 16 and 27 is approximately 19 mm and the inside diameter of the cover cap 20 is approximately 24 mm.

In the exemplary embodiment of the invention shown in FIG. 1, the likewise approximately cylindrically shaped housing 14 tapers in the direction of the base part 2 or of the distal end of the laser focusing handpiece 1, thus enlarging the fluid channel 8 formed between the covering cap 20 and the housing 14 in the region of Fluid connection 4. However, this does not necessarily have to be the case in all embodiments.

The covering cap 20 has at its front, proximal end 23 an opening 24, through which the fluid flow supplied via the fluid connection 4 as well as the bundled light emerging from the lens system 12 can emerge.

In this embodiment, the cap 20 also tapers conically at its proximal end 23, so that the fluid flow extending in the annular fluid channel 8 is bundled before exiting through the opening 24. The conical shape of the proximal end 23 of the covering cap only begins about 4 to 5 mm after the last, most proximal lens 12g of the lens arrangement 12, so that the fluid channel 8, and thus the fluid flow over the entire area of the lens arrangement 12 and in particular in the Area the most proximal lens 12g is approximately parallel to the light rays inside the lens system 12. In other embodiments of the invention, however, the conical shape of the cap can also begin only 6 or more mm after the last, most proximal lens 12g.

In addition to the above dimensions, the remaining dimensions of the shown here, concrete embodiment of the invention will be mentioned. The dimensions of alternative embodiments of the invention may of course differ from the dimensions given here purely by way of example. Deviations of up to 15% and more are possible. The total length of the Laserfokussierhandstücks 1 including base part 2 and head part 3 is about 230 mm. The base part 2 has a length of 122 mm and a diameter of about 29 mm. The head part 3 and the cover cap 20 covering it have a length of 108 mm, the outside diameter of the cover cap 20 being approximately 24 mm and the inside diameter of the cap 20 being approximately 22 mm. In the front, proximal region of the cap 20 near the proximal end 23, a shoulder or stop 28 may be provided for a focusing aid whose diameter is about 26 mm. Furthermore, the cover cap 20 at its distal end facing the base part 2 may have a shoulder which increases the maximum outer diameter of the covering cap 20 to the diameter of the base part 2, so that a flush closure is provided between the covering cap 20 and the base part 2. The distance of the focal point 26 from the proximal opening 24 of the Laserfokussierhandstücks 1 is approximately 12.3 mm in this embodiment. Furthermore, the focal point 26 is approximately 65.9 mm from the front, proximal end 9 of the optical fiber 7 spaced. The lens system 12 has in this embodiment of the invention a total length of about 8.8 mm.

The mode of operation of the exemplary embodiment according to the invention shown in FIGS. 1 and 2 will be explained below.

In the optical fiber 7 with a diameter of about 600 microns is introduced via a coupling to a laser with laser light in a wavelength range of about 1100 to 1400 nm. A wavelength range above 1150, 1175, 1200, 1250, 1275, 1300, 1308 or 1310 nm is preferred. In this wavelength range, the absorption of water does not show too great a dependence on the wavelength, so that certain wavelength fluctuations in this range do not automatically increase lead to a different surgical behavior of the laser radiation. On the other hand, the laser radiation should also be below a wavelength of 1350, 1330, 1325, 1300, 1275, 1250, 1225 or 1200 nm, since otherwise leave the plateau area. In this plateau region, a relatively favorable absorption and a favorable ratio of absorption to scattering in tissues with a relatively high water content such. B. in lung tissue.

The laser light is passed through the optical fiber 7 through the Laserfokussierhandstück 1 through to its head part 3. There, the laser light emerges from the proximal end 9 of the optical fiber 7. As a rule, the light diverges at an angle of approximately 20 ° ± 5 ° and thus forms a cone of light 19.

In the exemplary embodiment shown here, the light of the light cone 19 is received approximately completely in the lens system 12. Through the lenses 12a to g, the light beams of the light cone 19 are further expanded, then aligned in parallel and finally focused on a focal point 26, which has a diameter of 400 microns in this embodiment.

Depending on the distance 13, the diameter of the lens system 12 and the refractive indices of the individual lenses 12a to g can be generated with the laser focusing handpiece 1 according to the invention generally focus diameter in the range of about 500 to 50 microns.

From the ratio of the diameter of the focus 26 to the diameter of the optical fiber 7, a so-called focus factor can be derived, which represents a measure of the strength of the focusing achieved by the optical arrangement 11. Focusing factors of 1 to 0.16 or even less can generally be achieved with the laser focusing handpiece 1 according to the invention. The focus factor of the embodiment of the invention shown here is 400 μm: 600 μm, that is, 0.66. That is, light emerging from the optical fiber 7 having a diameter of 600 μm is focused to a comparatively smaller diameter of the focus 26 of 400 μm. The surface on which the light energy acts is thus reduced. The optical arrangement 11 therefore increases the per unit area z. B. mm ² or ² microns acting energy. In alternative embodiments of the invention, the focus factor depending on the application or need depending on the diameter of the optical fiber 7 and the optical assembly 11 also assume a different value in the range of about 1 to 0.16. At a focus factor of 1, the light energy 1 to 1 acting per unit area is transmitted from the optical fiber 7 into the focus 26. The thus focused laser light emerges from the lens system 12 and through the opening 24 of the cap 24 from the Laserfokussierhandstück 1 and provides the surgeon so a concentrated light energy, for. B. for laser surgery available. In the exemplary embodiment shown here, the focal point 26 is 12.32 mm from the opening 24 or 16.32 mm away from the last, most proximal lens 12g, which allows the surgeon ergonomically favorable working with the Laserfokussierhandstück 1. However, the distance of the focal point 26 from the aperture 24 and the last most proximal lens 12g, respectively, may vary in other embodiments of the invention. Depending on the numerical aperture of the optical fiber 7, the focal point 26 may be spaced more or less far from the opening 24. A large numerical aperture, as here with a value of 0.22, allows a relatively small distance of the focal point 26 from the opening 24 whereas a smaller numerical aperture, with an otherwise identical optical arrangement 11, a greater distance of the focal point 26 from the opening 24 allowed.

At the fluid port 4 is a fluid supply z. B. a compressed air leading hose 5 connected. The fluid flow generated via the fluid connection 4 and the fluid channel 8 flows around the lens system 12 like a jacket, is parallel to the beam path at the end of the lens system and is then bundled by the conical shape of the cap 20 at the proximal end 23 and emerges from the opening 24 Laser focusing handpiece 1 off. The fluid flow in this case has a pressure of about 2 to 7 Atü, preferably 3 to 6 Atü and in particular of about 5 Atü. By, exiting the opening 24 fluid, z. As air, particles that are at work with the focused laser, z. As in the laser surgery, ascending or blown away from the field in the direction of the Laserfokussierhandstücks 1 and prevents contamination of the Laserfokussierhandstücks 1 and 12 of the lens system.

The arrangement of the last, most proximal lens 12g or of the translucent element 25 and the conical shape of the proximal end 23, which retards the proximal end 23 and the opening 24, respectively, by which the opening 24 is kept small, further contribute to a reduction the contamination of the lens system 12 and the translucent element 25 by rising particles or splashing liquids at.

Nevertheless, should the last lens 12g or an upstream translucent element 25 become contaminated once, which may affect the performance of the laser focusing handpiece 1 in focus, the lens 12g, or the translucent element 25, can easily get through Unscrew the cap 20, peeling off the lens 12g, or the translucent element 25 together with the sleeve 27 of the sleeve 16 and attaching a new, clean lens 12g, or a new, clean translucent element 25 are replaced. This restores the original performance of the laser focusing handpiece.

In a vignettierten embodiment of the lens system 12, only a portion of the light cone 19 enters the lens system 12 and therethrough. This proportion is essentially dependent on the distance 13, the diameter of the lens system 12 and the numerical aperture of the optical fiber 7. The remaining portion of the light cone 19, which does not pass through the lens system 12, strikes the housing 14 and / or surrounding parts of the laser focusing handpiece 1, causing them to heat up. In this case, the fluid flow generated in the fluid channel 8 simultaneously provides for cooling. By surrounding the housing 14 in an annular manner, it transports the heat possibly accumulating there through the opening 24 to the outside.

Claims

claims A laser focusing handpiece (1) for focusing a laser beam emerging from an optical fiber (7) onto a focus (26) by means of an optical arrangement (11), the ratio of the diameter of the optical fiber (7) to the diameter of the focus (26) Focusing factor of Laserfokussierhandstücks (1) indicates, characterized in that the optical arrangement (11) is formed such that a focus factor of 1 or less results. 2. Laserfokussierhandstück (1) according to claim 1, characterized in that the optical arrangement (11) a plurality of series-connected optical lenses (12a - g). 3. Laserfokussierhandstück (1) according to claim 1, characterized in that the optical arrangement (11) comprises an aspherical lens. 4. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the optical arrangement (11) at its proximal, the focus-facing end has a releasably secured translucent element (25). 5. Laserfokussierhandstück (1) according to claim 4, characterized in that the light-transmitting element (25) has an optical lens. 6. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the optical arrangement (11) has a numerical aperture in the range of 0.1 to 0.22. 7. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the diameter of the optical fiber (7) in the range of 600 - 300 microns. 8. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the diameter of the focus (26) in the range of 500 - 50 microns. 9. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the wavelength of the laser beam is in the range of 1100 to 1400 nm. 10. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the Laserfokussierhandstück (1) has an air flow in its interior. 11. Laserfokussierhandstück (1) according to claim 10, characterized in that the air flow surrounds the optical arrangement (11) in an annular manner. 12. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the air flow has a pressure of 250-550 kPa, preferably from 300 to 500 kPa or 475 to 525 kPa and in particular of about 500 kPa 13. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the optical arrangement (11) in a detachably on the laser handpiece (1) mounted cap (20) is arranged. 14. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the distance of the optical fiber end (9) from which the laser beam exits to the optical arrangement (11) 25 to 35 mm, preferably 27 to 31 mm, and especially 28.5 to 29.5 mm. 15. Laserfokussierhandstück (1) according to at least one of the preceding claims, characterized in that the optical arrangement (11) is designed such that by the Lichtleitfaserende (9) exiting divergent light beam is approximately completely fed into the lens system (12). 16. Laserfokussierhandstück (1) according to at least one of claims 1 to 14, characterized in that the optical arrangement (11) is formed such that at least a portion of the light fiber end (9) exiting divergent light beam fed into the lens system (12) becomes.