Device for treatment of body tissue

Abstract

The invention relates to a device (17) for treatment of body tissue, in particular for the permanent occlusion of varicose veins, preferably in the lower limbs, of varicocele and / or of vascular malformations and / or for the use in aesthetic surgeries, preferably laser assisted lipolysis, and / or for tumor treatment by means of laser induced thermotherapy and / or photodynamic therapy, and / or in particular for the irradiation of brain tissue, for ear-nose-throat applications, in particular necrosis of tissue, for surface disinfection by laser light, for dermatologic treatment, including application on skin and / or nails and / or for treatment of pilonidal sinus, anal fistula and / or hemorrhoids, by means of a light diffuser (13) for irradiating said tissue by laser light energy and / or by electromagnetic radiation, wherein the light diffuser (13) is designed to irradiate the radiation laterally with respect to a longitudinal center axis of the light diffuser (13) and endoluminally. According to the invention, a sliding layer (51) is provided on an outer surface, in particular the outermost surface, of a distal end of the diffuser (13) at least in certain regions, preferably in the region of the front distal end of the diffuser (13) and / or in the region of the energy emission of the diffuser (13), in particular completely, in particular to reduce friction with and / or in particular to reduce adhesion to said surrounding tissue.

Description

[0001] Device for treatment of body tissue

[0002] This invention relates to a device for treatment of body tissue by means of a laser light diffuser endoluminally irradiating said tissue by laser light.

[0003] In particular, the device for treatment of body tissue is intended for the use for the permanent occlusion of varicose veins, preferably in the lower limbs. Moreover, the device is preferably intended for the use for the permanent occlusion of varicocele and / or vascular malformations. Alternatively or additionally, the device can be intended for the use in aesthetic surgeries, in particular such as laser assisted lipolysis, and / or for tumor treatment, preferably by means of laser induced thermotherapy (LITT) and / or photodynamic therapy (PDT).

[0004] Furthermore, the device can be intended for the use in irradiation of brain tissue, for ear-nose-throat applications, in particular necrosis of tissue, for surface disinfection by laser light, for dermatologic treatment, including application on skin and / or nails and / or for treatment of pilonidal sinus, anal fistula and / or hemorrhoids.

[0005] Said diffuser can be connected at its proximal end to a source of laser light energy via a flexible wave guide which can comprise a fiber optic core covered by an optical cladding having a refractive index smaller than that of the core.

[0006] As known to a person skilled in the art, the difference in a refractive index between core and the cladding can for example be achieved by lowering or increasing the refractive index between the core and the cladding; one may increase the refractive index of one and decrease the refractive index of the other. It may be beneficial in some embodiments to combine more than one core and / or more than one cladding, in arbitrary combinations and sequences. Then each layer may be designed to have an individual chemical composition and resulting refractive index, leading to potentially several different differences in the refractive index between the different neighboring layers. In the following, the terms "core" and "cladding" can mean one or several core(s) and / or cladding(s), respectively.

[0007] Imperfections can be provided in the cladding and / or in the core, wherein the imperfections are adapted to direct the light, preferably to refract and / or reflect the light propagating within the core and / or its optical cladding in generally radial directions. The imperfections can be designed as recesses or more generally as perturbation centers which interact with the light that is guided in the wave guide.

[0008] The imperfections designed as recesses can extend at least into the cladding and, preferably, into the core. In particular, the imperfections designed as recesses can differ from one another, in particular with regard to the depth. Preferably, at least one imperfection can extend solely into the cladding - and therefore not into the core -, wherein at least one further imperfection can extend into the cladding as well as into the core.

[0009] Imperfections designed as perturbation centers can be located

[0010] - within the core, and / or

[0011] - within the core and core-to-cladding interface, and / or

[0012] - within the core, core-to-cladding interface and the cladding, and / or

[0013] - within the core and the cladding.

[0014] Imperfections designed as perturbation centers are in particular to be understood as microstructures, such as, but not limited to, local variations in the refractive index of the material of the core and / or cladding, scattering centers, voids, and / or bubbles, in particular designed as micro-cracks or material impurities.

[0015] Further, imperfections of all kinds can be oriented, grouped and aligned - along the direction of energy propagation in the wave guide and / or orthogonally to it - so that a desired output beam profile can be created. This may include one or several changes in spatial density of the imperfections, gradually or step-wise, to compensate for the decreasing amount of energy guided within the wave guide, as energy is dissipated along the layout of the imperfections. In some embodiments an inhomogeneous or arbitrarily shaped emission profile can be desired, and the imperfections can be preferably chosen accordingly by methods such as reverse engineering or ray-tracing in a computer simulation.

[0016] Furthermore, a cap can be provided, wherein the cap is preferably transparent and / or translucent, preferably milky, to the laser light, enclosing the distal end of the core and its optical cladding in a fluid tight and / or liquid tight manner.

[0017] In particular, a fluid-tight enclosure prevents the passage of both liquids and gases, whereas a liquid-tight enclosure may prevent the passage of both liquids and gases or only liquids. The laser energy can pass through the cladding and the cap, wherein, preferably, a transparent cap does not modify the direction of emission intentionally in addition to the usual light refraction and where a milky cap can vary in degree of transparency, generally between different designs or specifically within one work-piece, to further support homogeneity and / or shaping of the emission characteristics.

[0018] In the medical field, diffusers can be used on the distal end of the wave guide as a means for scattering and / or redirecting the optical power in an even 360-degree cylindrical output along the length of the distal end of the core of the wave guide. Alternatively, a specifically designed emission profile, which is preferably non-symmet- rical has characteristic peaks or dips and which irradiates to one or several dedicated directions only, can be created by choosing the layout of imperfections accordingly. The 360-degree cylindrical output is for instance facilitated by roughening the core or by machining imperfections designed as grooves or threads into the glass of the fiber core deep enough to extract and scatter and / or redirect light travelling through the fiber core along the longitudinal axis thereof. Alternatively, imperfections can be obtained from high-energy short-pulse laser material processing as known to a person skilled in the art from general material processing of glass. Short pulses for material processing can be oriented and aligned such that the focal point is short and well-positioned within the core, within the core-to-cladding interface, or within the cladding. The light emerging from the imperfections or grooves irradiates an area of the tissue surrounding the diffuser with the optical power, making it useful for the aforementioned applications, preferably photodynamic therapy or coagulation and / or ablation of tissue, vessels or hollow organs. Depending on the desired emission profile the imperfections or grooves may be designed and aligned to emit light all around the fiber or into only one or several certain directions. When it is determined that for certain applications it is required to protect the distal end of the fiber, for example but not limited to a design in which it has its protective sheath removed, this distal end is conventionally surrounded and covered by a cap. Preferably, the cap is transparent and / or translucent, in particular milky, to the laser light emitted by the core.

[0019] In the field of illumination, it is known since long time to direct light from point light sources into one or both ends of a cylindrical rod made of refractive material and to redirect the light propagating within the rod in radial and circumferential directions of the rod by cutting either circular or spiral grooves into the outer surface of the rod as shown in FR 1 325 014. The light travelling within the rod exits therefrom at said grooves. If light is directed into the rod from only one end thereof, it is possible to terminate the other end by a conical reflector. In order to obtain a uniform radiation distribution over the length of the rod, it is further known to use deeper groves at positions of the rod more distant from the light sources to improve the uniform radiation distribution.

[0020] The same principle is also used in the medical field as exemplified in an embodiment of a laser light diffuser shown in Fig. 6 of EP 0 598 984 A1. In this embodiment, angled grooves are cut into the core of a wave guide under an angle to the longitudinal axis thereof. Further, this embodiment is provided with a conical reflector at the distal end of the core, and the section of the core comprising the groove as well as the conical reflector is enclosed in a cap transparent to the laser light.

[0021] The design of such diffusers varies depending on the desired length of the light emitting zone and light uniformity required as well as the available laser light energy.

[0022] In practice, it has been found that in a few cases after the treatment of the body tissue, the cap remains in the body tissue of the patient, wherein the core and the wave guide have been pulled out of the body tissue. Unfortunately, the remaining of the cap in the body tissue is a risk for infections and rejection reactions and therefore endangers the health of the patient. Not only the risk of an infection and / or a rejection reaction increases due to use of the known diffusers, but also the seceded cap and / or the aborted cap may rupture the body tissue and hence can lead to an internal bleeding.

[0023] The risk, that the light diffuser together with the core is pulled out of the body tissue, while solely the cap remains in the body tissue, cannot be prevented in the known devices.

[0024] Although there is a risk of undesired loosening of the cap, in some embodiments the use of the cap is in particular necessary to ensure optimum treatment results. Devices without caps usually have the problem that the tissue adheres to the wave guide and thus impairs or prevents movement through the human tissue. This leads to undesirable treatment results.

[0025] The object of the present invention is to provide a device for treatment of body tissue by means of a laser light diffuser which avoids or at least reduces the disadvantages of the prior art. The present invention relates to a device for treatment of body tissue according to claim 1 .

[0026] In particular, the device is used for the permanent occlusion of varicose veins, preferably in the lower limbs, of varicocele and / or of vascular malformations and / or for the use in aesthetic surgeries, preferably laser assisted lipolysis, and / or for tumor treatment by means of laser induced thermotherapy and / or photodynamic therapy, and / or in particular for the irradiation of brain tissue, for ear-nose-throat applications, in particular necrosis of tissue, for surface disinfection by laser light, for dermatologic treatment, including application on skin and / or nails and / or for treatment of pilonidal sinus, anal fistula and / or hemorrhoids.

[0027] According to the invention, the device comprises a light diffuser for irradiating said tissue by laser light energy and / or preferably more generally by electromagnetic radiation, wherein the light diffuser is designed to irradiate the radiation laterally with respect to a longitudinal center axis of the light diffuser and endoluminally.

[0028] The main advantage of lateral and endoluminal irradiation is that, especially when irradiating hollow organs or veins, the radiation can be aimed directly at the tissue to be treated and, in particular, as little radiation as possible is emitted in the undesired front direction, which would otherwise lead to undesired thermal damage of a deeplying area of the hollow organ or vein or of the waveguide itself.

[0029] In this way, the pain caused to the patient can also be minimized. In addition, the target tissue can be treated effectively. An even treatment of the tissue can also be ensured in this way.

[0030] According to the invention, a sliding layer is provided on an outer surface, in particular the outermost surface, of a distal end of the diffuser at least in certain regions, preferably in the region of the front distal end of the diffuser and / or in the region of the energy emission of the diffuser, in particular completely, in particular to reduce friction with and / or in particular to reduce adhesion to said surrounding tissue with which the device is in physical contact with.

[0031] Further, the device can be used for the medical application field "phlebology". The source of laser light may be a conventional laser source or a diode laser source or a bright light emitting diode (LED) or another suitable source of suitable electromagnetic radiation.

[0032] In particular, the sliding layer preferably counteracts any effects of adhesion of the device to the tissue or vice versa during the delivery of energy. Whether the user does not withdraw the device and / or diffuser continuously without interruption during energy delivery, e.g. along the vein, or generally sets the laser power too high, or there is more residual blood which can have a strong absorption of the laser energy than expected in the vein, there is preferably no adhesion and / or caking of the diffuser tip to the tissue and conversely no burning of blood or tissue residues on the surface of the device.

[0033] Another advantage is that if the device is used for the laser treatment of a medical condition which involves the sequential irradiation of more than one location, such as the treatment of both legs of a patient (or generally several veins) in phlebology or the treatment of more than one hemorrhoidal pile in proctology or the treatment of an entire tumor volume via more than one access site, , there is no need to wipe off blood or tissue residues on the tip of the diffuser, as there are preferably no residues on the outer surface of the diffuser. In the current state of the art, it is necessary to wipe the diffuser (under sterile conditions) several times during the treatment, which significantly increases the effort involved in the treatment as well as the pain experienced by the patient. Particularly, additional manipulation for cleaning the device can be avoided, which reduces the risk of damage in case of a small and fragile waveguide.

[0034] Preferably, the sliding layer can withstand the temperature rise due to energy emission throughout the entire application cycle of the device.

[0035] Thus, the invention enables preferably to overcome the disadvantages of the prior art with regard to the detachment and / or removal of the cap during the treatment of the body tissue. Particularly, smooth gliding of the outer surface of the diffuser along and / or through the body tissue or vessel or organ reduces mechanical stress.

[0036] Additionally, the invention reduces the risk for infections or rejection reactions on the basis of the treatment of the body tissue with the device and / or diffuser. In particular, an unexpected and / or unintended detachment and / or removal of the cap inside the patient's body is avoided.

[0037] The invention also has the advantage that the mandatory presence of a cap can be avoided. According to the invention, a cap can be provided, which is coated with the sliding layer at least in certain areas, but does not have to be. In the prior art, the cap is required in order to prevent the diffuser from adhering to the tissue. Thanks to its improved sliding behavior, the sliding layer according to the invention now enables the diffuser to be used either with or without a cap and can thus be optimally adapted to different usage situations or treatment methods.

[0038] Preferably, the sliding layer can be applied at least in certain areas which can be located at a position where energy is emitted or at a position where no energy is emitted on the outside surface of the cap or of the diffuser itself.

[0039] In particular, the sliding layer is formed as a coating and can thus in particular be coated or otherwise laminated to the diffuser. Alternatively or additionally, the sliding layer can be designed as a slip agent, preferably a permanently fixed slip agent, which can in particular withstand the temperature rise due to energy emission throughout the entire application cycle of the device. The slip agent can also be referred to as a sliding agent. In the following, both names are used synonymously.

[0040] The slip agent can be preferably a suitable hydrophobic coating and / or an additional surface layer of suitable thickness such as silicone or PTFE or ETFE.

[0041] More preferably, the coating and / or the sliding agent of the sliding layer can be applied, preferably coated and / or laminated, on the exterior and / or outer surface of the diffuser. In particular, the sliding layer forms at least in the region of the sliding layer the outermost part of the diffuser.

[0042] Thus, according to the preferred embodiment the sliding layer and / or slip agent can be implemented as a coating or surface layer of sufficient thickness and durability for the application in a surgery. The slip agent can be added to the entire outside surface of the diffuser, preferably the cap, or to specific portions of the surface only. Depending on the emission profile and requirements derived from the intended use it can be beneficial to add the sliding layer only in some parts of the emission profile and / or in areas of the diffuser surface, in particular of the cap surface, in which no energy is transferred.

[0043] According to a preferred embodiment of the present invention, the sliding layer can comprise and / or can consist of a plastic material. Alternatively or additionally, the sliding layer can comprise or can consist of a material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroethylene, polysiloxane, higher order polysiloxane and mixtures thereof. Preferably, the material of the sliding layer comprises silicone or consists of silicone. The aforementioned materials enable in particular the optimized gliding of the diffuser in the body tissue.

[0044] Furthermore, the aforementioned materials enable in particular that the emitted radiation energy is at least substantially not influenced by the sliding layer which can be designed transparent or translucent for the radiation energy emitted by the diffuser.

[0045] Preferably, the diffuser is connected and / or connectable at its proximal end to a source of laser light energy and / or electromagnetic radiation via a flexible wave guide. The source can be a part of the device, but not necessarily has to be a part of the diffuser. When the source is not part of the device, the device is in particular designed to be connected to such a source and further is in particular designed to transport the radiation, in particular the laser light, provided by the source. The source is preferably a laser light source and / or a in particular bright light emitting diode (LED).

[0046] The wave guide can be designed as an optical fiber, but not has to be an optical fiber.

[0047] In particular, the wave guide has at least one radiation emitting surface which is designed to emit the radiation laterally with respect to a longitudinal center axis of the light diffuser and endoluminally. The lateral radiation enables makes it possible for the target tissue, which is positioned laterally with respect to the longitudinal axis of the wave guide during the treatment, to be effectively "hit" by the lateral radiation.

[0048] The laser light energy and / or the electromagnetic radiation provided by the source can have a wavelength of (1450 + / - 30) nm, (1950 + / - 40 nm) and / or a wavelength between 2700 nm to 3100 nm, preferably a wavelength of (2770 + / - 40 nm) and / or (2900 + / - 40) nm, and / or a wavelength of (6100 + / - 40) nm. The aforementioned wavelengths are advantageous for the absorption of the radiation energy in the target tissue. This is based on the fact that the aforementioned wavelengths of radiation energy, in particular laser light, enable maximum absorption in water, which is generally an essential component of the human tissue. In particular, the strong absorption of energy in the tissue implies that less laser power is required altogether and / or the penetration depth can be less, which reduces preferably damage to neighboring tissue and the associated intra- and post-operative complications such as for example pain or parasthesia due to nerve damage.

[0049] In particular, reducing the total energy or energy density of laser light energy and / or the electromagnetic radiation to the minimum that is absolutely required for achieving the desired therapeutic effect in a surgery is preferred over higher total energy or higher energy density because the occurrence rate of undesired side effects scales with the amount of energy applied. Selection of the most suitable wavelength for the target tissue's chromophore is in particular a critical step towards reduction of energy of laser light energy and / or the electromagnetic radiation. Depending on the target tissue to be treated or properties of the surrounding tissue to be protected from collateral damage the wavelength may be selected accordingly.

[0050] According to a further preferred embodiment of the present invention, the distal end of the diffuser comprises in particular a protection means, which can also be named protective means, which encloses at least a protection part of the wave guide, preferably a part of an energy emitting segment and / or a part of a segment comprising the radiation emitting surface or surfaces, more preferably the whole length of the energy emitting segment and / or the whole length of the segment comprising the radiation emitting surface or surfaces.

[0051] The covering of the radiation emitting surface(s) with the sliding layer can n particular ensure that in the region of the energy emission the sticking and / or adhering of the tissue to the diffuser can be avoided.

[0052] The energy emitting segment and / or the segment comprising the radiation emitting surface or surfaces has preferably a length up to 10 cm, preferably a length between 0,1 to 100 cm, more preferably between 1 to 50 mm, in particular between 3 to 4 mm. These lengths enable a broad, in particular sleeve-shaped, radiation of the radiation energy. This leads to improved treatment of the target tissue, as a gentle large-area irradiation can be ensured rather than local hotspots. The protection means is preferably part of the wave guide or is connected to the wave guide more preferably in a fluid tight and / or liquid tight manner. The protection means can thus be securely connected to the diffuser. Unwanted penetration of liquids and / or fluids can also be prevented. Therefore, the protection means encloses in particular the protection part in a fluid tight and / or liquid-tight manner.

[0053] In particular, the protection means comprises the outer surface, preferably the outermost surface, of the diffuser. Therefore, the protection means can be coated with the sliding layer.

[0054] The protection means can improve the protection of the inner parts of the diffuser, in particular an optical fiber. The protection means further can protect the diffuser from mechanical stresses.

[0055] The protection means can be formed by different parts of the diffuser. Therefore, the protection means can be either a coating or a cap of the diffuser, preferably enclosing the distal end of the wave guide.

[0056] The cap can be designed as a fused silica cap which can improve the connection to the wave guide preferably by fusing.

[0057] Alternatively or additionally, the cap comprises and / or consists preferably of a plastic material and / or comprises or consists preferably of a material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroethylene, polysiloxane, higher order polysiloxane and mixtures thereof.

[0058] In particular, the material of the cap comprises silicone or consists of silicone.

[0059] All the aforementioned materials of the cap can ensure a good connection to the diffuser and a protection of the inner parts of the diffuser.

[0060] Furthermore, the protection means is designed preferably as a coated layer of the wave guide, a protective sheath and / or an outer sheath of the protective sheath of the wave guide.

[0061] In this regard, it is in particular provided that the protection means is transparent or translucent to the radiation energy in particular emitted by the diffuser. The energy can therefore not be diffused by the protection means which is provided for the protection of the diffuser and not for influencing the radiation energy emitted by the diffuser.

[0062] Further, the sliding layer is preferably provided at least partially, preferably completely, on the outer surface of the protection means, in particular wherein the sliding layer is provided at least in certain regions, preferably in the region in the outermost distal end of the protection means, preferably completely, on the protection means. Alternatively, the protection means can be designed as the sliding layer.

[0063] In particular, this makes it possible to combine several functions (protection means, sliding layer, etc.) into one component. This leads to a number of advantages, in particular a simpler production process can be guaranteed. In addition, the entire diffuser can be made smaller and / or slimmer, which is also advantageous in terms of treatment.

[0064] Preferably, the wave guide comprises at least one fiber optic core covered by at least one cladding having a refractive index smaller than that of the core, in particular wherein the wave guide is an optical fiber.

[0065] The fiber core is preferably coaxially surrounded by the cladding, in particular wherein a jacket mechanically protects the core, and prevents, in particular, the fiber from breaking during the use or transport.

[0066] In particular, cladding and jacket may be one layer with both functions.

[0067] The cladding is in particular intended to prevent the light waves from escaping or being emitted out of the core. Light energy travels in the path of the least optical resistance, in particular known as Fermat's principle.

[0068] The sliding layer is preferably transparent or translucent for the emitted laser energy, as mentioned before. Thus, the radiation energy is preferably not influenced by the sliding layer in a unpreferred way.

[0069] Further, the sliding layer can have a material thickness of at most 0.5 mm, preferably at most 0.1 mm, more preferably at most 0.05 mm, in particular between 0.01 mm to 0.1 mm. Thus, the sliding layer does at least substantially not increase the diameter of the diffuser in a way that would lead to a disadvantage during the treatment in small hollow organs, instrument channels or veins.

[0070] According to a preferred embodiment of the present invention, a cap which is preferably transparent or translucent to the radiation energy enclosing the distal end of the core and its cladding in a fluid tight and / or liquid tight manner is provided. The cap can be designed as the protection means, as explained above. However, a cap can also additionally be provided to the protection means. The cap in particular protects the inner wave guide from damage.

[0071] Preferably, the light diffuser irradiates circumferentially said tissue by laser light energy and / or electromagnetic radiation. Thus, the radiation can be directed lateral and circumferential for irradiating the target tissue in an effective way.

[0072] To emit the energy, imperfections are provided in the wave guide. The imperfections are in particular designed to influence the laser light which is directed along the wave guide. Preferably, in the cladding and / or in the core and / or in a boundary between the core and the cladding the imperfections are provided. Further, the imperfections can be designed either as one or several recess(es) or as one or several perturbation center(s) and adapted to direct the electromagnetic radiation, preferably to refract and / or reflect the laser light energy propagating within the core and / or its cladding in generally lateral, preferably radial, directions. In particular, the perturbation centers are implemented as local variations in the refractive index of the material of the core and / or cladding, scattering centers, voids, and / or bubbles, in particular designed as micro-cracks or material impurities.

[0073] As light waves in particular travel down the core and encounter the etching of the core and imperfections of the cladding and / or core, the waves will begin to escape through the imperfections and be emitted into the surrounding vessel and / or vein.

[0074] With regard to the imperfections that can be preferably designed as perturbation centers reference is made to the aforementioned explanations. These explanations apply also to the preferred embodiment of the invention, in which the perturbation centers are provided in the wave guide. One advantage of the perturbation centers is that they can leave the outer surface of the glass fiber unchanged, so that practically the thinner dimensions of a bare fiber (diffusor without cap) are particularly achieved. However, the diffuser has in particular the advantage of being rounded at the front end. In particular, no cap and / or air gap is required as a refractive index difference. In addition, the fiber can be inserted into a vein, for example, without major effort, e.g. using a thinner cannula instead of the larger and more expensive insertion set that is often used for products with the thicker glass cap.

[0075] Furthermore, the perturbation centers are faster and / or easier to produce than the recesses, which are also possible, because other layers of the wave guide and / or the diffusors like the buffer layer and / or the jacket layer can remain on the diffusor.

[0076] According to a further preferred embodiment of the present invention, the imperfections are preferably designed as perturbation centers which are aligned in groups or patterns along the longitudinal extension of the wave guide, in particular of the distal segment of the wave guide. This arrangement enables improved radiation of the energy, in particular of the laser light, especially preferably a circumferential radial radiation. The perturbation centers can enable targeted radiation, wherein a comparatively simple generation of the perturbation centers can be achieved.

[0077] Preferably, the perturbation centers take form of one or several geometries, in particular as circle, spiral, line and / or cuboid. The design of the geometry of the perturbation center can depend on the desired radiation emission profile and / or the form of the wave guide. Different geometries therefore enable an optimized behavior of the device.

[0078] More preferably, each geometry of the perturbation centers can be oriented along or orthogonally with respect to the longitudinal extension of the wave guide. The arrangement of the perturbation centers is preferably chosen in consideration of the desired emission profile and thus the arrangement can influence the emission profile and enable an adaption of this profile.

[0079] In particular, the geometries of the perturbation centers can be different or can repeat within the area provided with the imperfections. Therefore, the emission profile can be provided over a longer length of the wave guide, wherein the radiation emission surface(s) can increase with regard to the number of the perturbation centers. While, as known to a person skilled in the art, a higher local spatial density of perturbation centers is generally associated with a higher local intensity of laterally emitted radiation, under certain conditions it may be beneficial to keep short segments unprocessed between neighboring areas with perturbation centers. Experiments showed that counter-intuitively a continuous array of perturbation centers achieves a lower emission rate than sequential arrays of perturbation centers with unprocessed sections in-between.

[0080] In particular, when arrays of perturbation centers of in particular 500 pm + / - 20% extension each are aligned along the longitudinal axis of the waveguide, then an unprocessed gap of preferably around 150 pm to 350 pm extension, more preferably of around 200 pm to 300 pm extension, in particular of 250 pm + / - 20% extension, along the axis of the waveguide between neighboring arrays of perturbation centers should be maintained.

[0081] According to a further preferred embodiment of the present invention, the perturbation centers are only provided and / or located in the fiber core, preferably only in the innermost cross-section of the fiber core defined by the radius range from 0 to 80 % of the fiber core, more preferably defined by the radius range from 0 to 60 % of the fiber core, in particular defined as the radius range from 0 to 40% of the fiber core, in particular each starting from the center of the fiber core. Therefore, the function of the cladding is preferably not negatively influenced by the imperfections which are in particular only provided in the fiber core.

[0082] Selection of the distribution, orientation, alignment and / or spatial density of perturbation centers can be derived from the planned irradiation zone characteristics, that is typically determined based on the target tissue to be irradiated in the surgery. Likewise, an irradiation zone can be planned such that certain tissue or tissue segments, especially tissue which is to be spared from the laser light energy and / or the electromagnetic radiation in the surgery, receive less energy than others. This way, the suitable design of the irradiation zone can help reducing complications, including pain or delayed healing.

[0083] A further preferred embodiment of the inventive device for treatment of body tissue is characterized in that the outer surface of said optical cladding is fused in the region between said imperfections and / or in the region, where said imperfections are located, to the inner surface, in particular the inner diameter, of the cap. Alternatively or additionally, the inventive device for treatment of body tissue is preferably characterized in that the outer surface of said optical cladding extending over a distance in front and / or behind the region provided with the imperfections is fused to the inner surface, in particular the inner diameter, of the cap.

[0084] A further embodiment according to the present invention is characterized in that the distal end of the diffuser, in particular the distal end of the cap, and / or the outermost surface of the diffuser and / or the distal end of the protective means and / or the distal end of the wave guide is rounded, thickened, widened and / or conical shaped. These forms of the diffuser are preferred for certain medical purposes.

[0085] One may prefer a straight cut tip in one example application in which the device is hovered above the tissue to be irradiated, yet other applications may require a conically pointed tip which allows to penetrate tissue for irradiation from within, yet other applications may require a rounded tip which is atraumatic and allows to be inserted into a narrow hollow organ or path, such as a blood vessel, without penetration of its wall. The exact tip design and geometry preferred for each application type depends strongly on the environment the device is used in.

[0086] Further, the device can be used for the medical application field "tumor treatment", preferably by means of laser induced thermotherapy (LITT) and / or photodynamic therapy (PDT).

[0087] According to a preferred embodiment of the invention the cap is in particular fused at least partially and / or at least in partial areas, namely at least to the optical cladding in the region between the imperfections and / or preferably - at least partially - in the regions in front (before) and / or behind the imperfections.

[0088] The region in front and / or behind the region provided with the imperfections refers in particular to the direction of the laser light propagation, in particular wherein the laser light first travels through the region in front of the region provided with the imperfections, then through the region provided with the imperfections and subsequently through the region behind the region provided with the imperfections.

[0089] Due to the fusing of the cap and the optical cladding the cap is, in particular, firmly bonded to the optical cladding and cannot be pulled off during the treatment of the body tissue. This is also advantageous with regard to the detachment and / or removal of the cap during the treatment of the body tissue. The cap can be firmly attached to the optical cladding at least in the fused region and / or in the fused partial areas. The invention reduces the risk for infections or rejection reactions on the basis of the treatment of the body tissue with the device. In particular, an unexpected and / or an unintended detachment and / or removal of the cap, e.g. in the veins of the patient, can be avoided.

[0090] Preferably, the slip agent is applied to the cap surface after fusing said cap to the optical fiber to avoid excessive temperature stress for the slip agent. The slip agent may be applied by means of spray-coating, dipping bath, shrink-coating process, or other conventional ways of applying a coating to a substrate.

[0091] Furthermore, the fluid tight and / or liquid tight enclosing of the distal end of the core is improved for the reason that the cap is not only bonded at its distal end to the wave guide.

[0092] Preferably, a short longitudinal length of the bared optical cladding of the core preceding and / or following the region provided with the imperfections can be fused to the cladding, in particular to counter the reduced mechanical stability caused by the imperfections. The inner diameter of the cap is preferably about the same as the outer diameter of the core and cladding combined. The optical cladding can be fused at least in some regions and / or partial areas between said imperfections to the inner diameter of the cap as well.

[0093] Whether the light is refracted or reflected depends in particular on the form of the imperfections and the angle of incidence of the laser light. The angle of incidence can be of such a size that a total internal reflection occurs. Moreover, a refraction or reflection of the light can depend on the relation of the refractive indices. For light, refraction follows in particular Snell's law which states that for a given pair of media the ratio of the sines of the angle of incidence on and the angle of refraction a.2 is equal to the ratio of the indices of refraction (n2 / ni) of the two media. The index 1 refers to the first media, namely the core, wherein the index 2 refers to the second media, namely the cladding: The total internal reflection is in particular defined by the critical angle. If the angle of incidence is greater than the critical angle, total internal reflection occurs. The light is reflected. Assuming that light waves or other electromagnetic waves are propagating in an isotropic media, there is a well-known formula for the critical angle in terms of the refractive indices. The angle of incidence has to be greater than for total internal reflection, wherein the index crit is referring to the critical angle.

[0094] According to a preferred embodiment of the invention, the outer surface of said optical cladding is fused continuously and / or circumferentially and / or fully in the region between said imperfections to the inner surface, in particular the inner diameter, of the cap. Therefore, the fused region between said imperfections is designed in such a way that the fused region, in particular the fused partial area, is provided continuously and / or circumferentially and / or fully. This can in particular ensure the firm attachment of the cap to the optical cladding.

[0095] Alternatively or additionally, the outer surface of said optical cladding extending over a distance in front and / or behind the region provided with the imperfections is fused, preferably continuously and / or circumferentially and / or fully, to the inner surface, in particular the inner diameter, of the cap. Therefore, the fused region - in particular the region between said imperfections and / or the region in front and / or behind the region provided with the imperfections - can be fused in such a way that the fused area can be provided 360 degrees circumferential around the optical cladding.

[0096] In another preferred embodiment the outer surface of said optical cladding is fused partially, preferably in a point-like manner and / or with longitudinal welds, in the region between said imperfections to the inner surface, in particular the inner diameter, of the cap and / or the outer surface of said optical cladding extending over a distance in front and / or behind the region provided with the imperfections is fused partially, preferably in a point-like manner and / or with longitudinal welds, to the inner surface, in particular the inner diameter, of the cap. Therefore, the fused area can be provided in several fused regions (fused partial areas), in particular wherein the fused regions are designed as partial sections. It has been found in experiments that have been carried out in connection with the invention that even partially fused region(s) can provide a firm attachment of the cap to the optical cladding. The design of the fused region(s) depends in particular on the fusing method of the optical cladding to the cap.

[0097] Moreover, there can be non-fused regions between the optical cladding and the cap in which there are no imperfections provided and / or in which the cap is not fused to the cladding. The fused area between the cap and the optical cladding can be provided via the fused regions (partial areas) which can - in each case - be designed as a full and / or partial surface applied fusing. The fused partial areas enable in particular the firm attachment of the cap to the optical cladding, wherein according to the invention the design of the fused area and / or the fused region(s) can depend on the fusing method.

[0098] Furthermore, in the fused regions, in which the cladding is fused to the cap (fused regions), the cladding and the cap are, preferably, firmly bonded, in particular in a material-locking manner. In particular, no additional glue is necessary for the firmly bonding of the cap and the cladding in the fused regions. Due to the material-locking manner of the bonding of the cladding and the cap, the cap is inseparable and / or inextricably linked and / or connected to the cladding. Preferably, the cap cannot be detached from the cladding.

[0099] More preferably, the core of the wave guide has an inner diameter between 100 and 1000 pm, preferably between 200 and 800 pm, more preferably between 300 and 700 pm and in particular between 350 and 600 pm. These diameter ranges enable in particular to direct the light and further to provide the imperfections which can extend into the core. The imperfections can surround the core circumferentially so that the diameter has to be great enough with regard to the needed depth of the imperfections.

[0100] The outer diameter of the cladding can be greater as the outer diameter of the core for the reason that the cladding surrounds - at least partially - the core. The cladding can have an outer diameter between 110 and 1200 pm, preferably between 210 and 960 pm, more preferably between 360 and 840 pm and in particular between 400 and 720 pm. In particular, the core can have a diameter between 530 and 555 pm, in particular wherein the cladding can have an outer diameter between 580 and 610 pm.

[0101] Alternatively or additionally, the core can have an outer diameter between 380 and 410 pm, in particular wherein the cladding can have an outer diameter between 420 and 450 pm.

[0102] These core dimensions are particularly suitable for minimally invasive surgery and are compatible with most of the commonly used radiation sources on the one hand and match the dimensions of usual surgical instruments on the other hand.

[0103] Further, the sheath thickness of the cladding can be between 1 % to 40 %, preferably between 5 % to 20 %, of the outer diameter of the core. Therefore, the thickness of the cladding can depend on the outer diameter of the core.

[0104] In addition, a protective sheath can be provided, preferably at the distal end of the wave guide. The protective sheath can be joined to the cap. The protective sheath can further surround the optical cladding and / or the core. Preferably, the protective sheath is designed in such a way that the light directed through the core cannot be transmitted via / over the protective sheath. In particular, the protective sheath can comprise at least one buffer layer, preferably adjacent to the optical cladding of the core, and / or an outer sheath. The outer sheath can be designed as a jacket which surrounds at least the core.

[0105] The buffer layer can further be placed adjacent to the cap and / or between the cap and the core, preferably in a non-fused region. Alternatively or additionally, the buffer layer can be adjacent and / or adjoin on the outer sheath and / or the outer sheath can be adjacent and / or adjoin on the cap, preferably at least indirectly.

[0106] The protective sheath and / or the outer sheath can further be designed as a, preferably extruded, plastic coating.

[0107] In addition, the outer sheath can be joined to the cap.

[0108] Preferably, the protective sheath and / or the outer sheath is joined to the protection means. According to another preferred embodiment of the present invention, the device can be characterized in that the protective sheath and / or the outer sheath (also called jacket) is at least partially removed at the distal end of the wave guide to bare the core and its optical cladding. Therefore, the distal end of the wave guide can be designed with the protective sheath being removed, in particular so that the core and its optical cladding can face the cap.

[0109] Preferably, the imperfections can extend into the cladding, preferably to bare the core, and / or into the core. The depth and / or the width - in particular the extension into the cladding and / or into the core - can be designed in such a way - depending on the form of the imperfections - that the light transmitted and directed along the core can be decoupled or coupled out and therefore can be sent out or emitted via the optical cladding and the cap. The light is reflected and / or refracted by the imperfections, wherein the form of the imperfections can be designed in such a way that the greater percentage of the light can either be refracted or reflected. The imperfections can reduce the sheath thickness of the cladding within the imperfections and therefore can change the light propagation behavior.

[0110] In particular, the protective sheath and / or its outer sheath is provided additionally to the protection means or is designed as the protection means or a part of the protection means. The embodiment in which the protective sheath is the protection means is associated with several advantages. Firstly, the cap as a stand-alone component can be omitted if necessary and a simple, cost-effective structure of the diffuser can be achieved, which nevertheless has improved sliding behavior when treating human tissue. A simpler assembly process can also be guaranteed when fewer components are involved. The entire diffuser can also be made smaller and / or slimmer in terms of the relevant dimensions. Finally, from a device safety point of view there are preferably fewer components that could potentially become detached during treatment.

[0111] Further, the imperfections can be designed as grooves, in particular spiral grooves, that are adapted to refract and / or reflect the light propagating within the core and its optical cladding in generally radial directions.

[0112] Depending on the desired emission profile the imperfections of grooves may be designed and aligned to emit light all around the fiber or one or several certain directions. The grooves can comprise at least two spiral grooves that extend through the optical cladding into the core. Alternatively or additionally, the grooves can extend at least into the cladding and, preferably, into the core. The depth and / or the width of the grooves can vary, in particular wherein the depth and / or width of the grooves can increase in the direction of the distal end of the core.

[0113] The successive grooves of the respective spiral grooves can alternate along the outer surface longitudinally extending from the core and its optical cladding.

[0114] In another preferred embodiment of the present invention, the imperfections can comprise at least one circular and / or elliptical groove and / or ring-like groove. The circular groove can surround the core and the cladding circumferentially.

[0115] Moreover, the imperfections can also comprise at least one longitudinal groove. Also, a point-like and / or broken imperfection / groove and / or a recess in the form of a spherical cap is possible. The form of the imperfections / grooves can vary. Also, a combination of different forms of imperfections / grooves is possible.

[0116] The imperfections / grooves are designed in such a way that the light propagating within the core can be emitted out or coupled out of the core and the cladding. The light is reflected and / or refracted on the boundary surface of the imperfection / groove. The greater the depth and / or width of the imperfections / grooves is, the greater the percentage of the intensity of the light will be which "leaves" (is emitted) the core and the cladding - for the reason that the light is in particular refracted on the boundary surface of the imperfections / grooves.

[0117] The imperfections can also be provided in a patterned structure and / or with different forms. In particular, the pattern of the imperfections is designed in such a way that a substantially uniform emission profile is reached over the length of the region provided with the imperfections.

[0118] In a further preferred embodiment of the present invention, the depth and / or the width and / or the length of the imperfections, preferably of the grooves, or groups and / or arrays of aligned perturbation centers increases in a direction of the distal end of the core. In particular, the depth and / or the width and / or the length, preferably the depth and the width, of the imperfections or groups and / or arrays of aligned perturbation centers increases up to 1000 %, preferably up to 800 %, more preferably up to 400 %, in particular with regard to the smallest depth and / or width and / or length of the imperfections or groups and / or arrays of aligned perturbation centers.

[0119] Preferably, the greatest depth and / or width of the imperfections is between two to four times greater than the depth and / or width of the smallest depth and / or width of the imperfections.

[0120] In particular, the depth and or width of the imperfection can increase up to 400 pm, preferably up to 300 pm, more preferably up to 200 pm and / or the depth and or width of the imperfections can vary between 1 pm to 400pm, preferably between 10 pm to 200 pm.

[0121] The increasing of the depth and / or width of the imperfections in particular allows to ensure an essentially uniform and / or equal emission profile of the laser light.

[0122] The depth and / or width of the imperfections increases in the direction of the distal end of the core for the reason that a higher amount and / or percentage of the intensity of the laser light has, in particular, to be emitted via the imperfections. For example, it is sufficient that 1 to 10 % of the percentage of the intensity of the laser light is emitted at the "first" imperfection. That can lead to the fact that the intensity of the laser light decreases after the laser light has passed the "first" imperfection. If the same amount of the laser light is intended to be emitted at the "second" imperfection, the intended percentage of the intensity of the laser light to be sent out has to be higher. This percentage can be calculated to be 1.01 to 1.11 % based on the initial percentage of 1 to 10 % from the "first" imperfection. Further, the aforementioned percentage can be reached by increasing the width and / or depth of the imperfection.

[0123] The resulting power density along the region provided with the imperfections can be controlled by altering and / or customizing the size, placement and / or number of the imperfections, in particular of the grooves. Adjusting the overall dimension and geometry of the imperfections will, in particular, directly impact the amount of light energy leakage and / or radial light energy dissipation, power density delivered along the region provided with the imperfections, direction of light energy, and / or power that will escape from the distal end of the core.

[0124] Further, the device can be used for the medical application field "proctology", in particular for treatment of pilonidal sinus or anal fistula. In a further preferred embodiment of the present invention, the material of the core and / or the cladding contains or consists of a material selected from the group of fused silica, in particular quartz glass, chalcogenide glass, arsenic sulfide glass, silver chloride glass, silver bromide glass and mixtures thereof. Further, the core can contain and / or consist of quartz glass, chalcogenide glass, arsenic sulfide glass, silver chloride glass, silver bromide glass and mixtures thereof.

[0125] Moreover, the material, preferably the exact material composition of the core, in particular the fused silica material of the core, can differ from the material, preferably the fused silica material of the cladding, preferably to ensure the different refractive indices.

[0126] The material of the cladding and / or of the core can be doped, in particular to ensure the different refractive indices. In particular, the cladding can be doped with fluorine and / or boron. The core can, alternatively or additionally, be doped with germanium and / or phosphor. Preferably, the cladding is doped with fluorine, wherein the core is not doped. The doping can enable that the cladding has a smaller refractive index than the core so that the light propagation behavior on the border surface to the core is characterized in that the light is reflected (back) in the core.

[0127] Preferably, the chalcogenide glass of the cladding and / or the core is doped, wherein, preferably, at least one of the fiber core and the cladding is doped with germanium, selenium, silver, indium or tellurium or rare earth elements. Also, this doping can enable the different refractive indices.

[0128] The preferred material, namely fused silica, of the cladding and the core can exhibit fairly good optical transmission over a wide range of wavelengths. Furthermore, silica is also relatively chemically inert. In particular, it is non-hygroscopic (it does not absorb water). As already mentioned, silica glass can be doped with various materials, wherein one purpose of doping, in particular of the core, is to rise the refractive index (e.g. with germanium dioxide (GeCh) and / or aluminum oxide (AI2O3)) and another purpose of doping, in particular of the cladding, is to lower it (e.g. with silicon tetrafluoride (SiFzi) and / or boron trioxide (B2O3)).

[0129] The material of the cap can comprise glass and / or fused silica. This material of the cap can ensure the fluid tight and / or liquid tight connection between the cladding, which in particular comprises as material fused silica, and the cap. Therefore, glass and / or fused silica - as materials of the cladding and cap - can be welded and / or fused in the fused regions.

[0130] The length of the region provided with the imperfections, preferably the recess(es) and / or perturbation center(s), can range between 0.1 to 100 mm, preferably between 1 to 50 mm, more preferably between 3 to 4 mm. The length of the region provided with the imperfections corresponds in particular to the length over which the light is emitted and / or sent out. Therefore, the efficiency of the use of the device is increased for the reason that the laser emission profile is in particular not related to a so-called "front firing". Furthermore, the emission of the laser light can be circumferential around the core, preferably around 360 degrees.

[0131] In particular, the reflector mentioned earlier is adapted to reflect the laser light energy and / or the electromagnetic radiation.

[0132] Furthermore, the distal end of the core can be terminated by a reflector. The reflector can be formed by the distal end of the core and / or the cladding. The core and / or the cladding can end and / or lead into the reflector.

[0133] The reflector can have a conical shape, wherein the cone angle of the reflector designed as a reflecting cone can further be around 60 degrees.

[0134] Alternatively or additionally, the reflector, in particular designed as a cone, is shaped and / or curved inwards, facing to the distal end of the diffuser, or outwards, facing away from the distal end of the diffuser and / or has a concave or convex design.

[0135] Having a portion of light reflected back by the reflector along the wave guide in the direction of the source is associated with the advantage of increased and more homogeneous lateral output from the region provided with the imperfections.

[0136] The shape of the reflector can have an influence on the refractive behavior of the laser light. The laser light can either be refracted or reflected on the boundary surface of the reflector. The geometry of the reflecting cone (reflector) can therefore be designed in such a way that the laser light is emitted and / or sent out via the reflecting cone and / or in such a way that at least 20 %, preferably at least 50 %, of the intensity of the laser light that hits the reflector is reflected, in particular by total internal reflection. The greater the cone angle is, the higher the percentage of the reflected laser light can be. Additionally or alternatively, the reflector can have a conical reflecting cone surface, wherein the cone angle of the reflecting cone is about 55 degrees to 90 degrees, preferably 60 to 82 degrees, more preferably 60 + / - 4, 68 + / - 4 and / or 74 + / - 4 degrees. These angles present very suitable emission angles for irradiation of body tissue.

[0137] The term "reflector" should, thus, be understood in particular in a broad sense so that the reflector can also be designed to at least partially refract light.

[0138] Preferably, the proximal end of the bore of the cap is provided with a section, preferably in a non-fused region, having an increased inner diameter corresponding to the outer diameter of the buffer layer and / or the diameter of the outer sheath and / or the diameter of the protective sheath and / or the outer diameter of the cladding. The buffer layer can be part of the protective sheath, wherein the buffer layer can surround the cladding and / or the core in the section having the increased inner diameter corresponding to the outer diameter of the buffer layer.

[0139] Furthermore, the section having the increased inner diameter at the proximal end of the cap is glued to the at least one buffer layer and / or to the protective sheath and / or to the outer sheath and / or to the core and / or to the cladding. The buffer layer can be placed at the proximal end of the cap and can further be placed adjacent to the cap. The glue can further be additionally provided, in particular to ensure a smooth transition between the outer surface, in particular the outer diameter, of the cap and that of the outer sheath. The glue can connect the cap to the outer sheath. Further, the glue can connect the buffer layer to the inner surface of the cap.

[0140] In particular, the rear end of the cap is glued to the outer sheath, wherein the inner surface of the cap can be at least partially glued to the buffer layer, the core and / or the cladding and / or the outer sheath.

[0141] The outer surface, in particular the outer diameter, of the cap and / or the outer surface, in particular the outer diameter, of the protective sheath and / or the outer surface, in particular the outer diameter, of the outer sheath may represent the smaller outer surface, in particular the smaller outer diameter. In particular, the outer diameter of the cap may be larger or smaller than the outer diameter of the protective sheath and / or outer sheath. Moreover, the glue can be placed between the outer sheath and the cap and / or in the section to connect the cap to the cladding and / or to the core, preferably in a nonfused region.

[0142] In particular, the inner surface of the bore of the cap is provided in full or in parts with an anti-reflective coating.

[0143] In particular, the imperfections, preferably the grooves, are produced by cutting by means of a CO2 laser beam or a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm by rotating the core and its optical cladding around its longitudinal axis relative to the laser beam and axially moving the laser beam and / or the core and its cladding around the longitudinal axis of the core in a synchronized manner with the rotation of the core. This production of the imperfections is easy in handling and can create well defined imperfections to manipulate the propagation behavior of the laser light in an efficient way.

[0144] In order to maximize the light output density, this spatial distance of imperfec- tions / grooves in longitudinal direction must be minimized. This, however, would in particular lead to fairly rapid change in depth of the imperfections / grooves and fairly steep flange angles and an imperfection / groove surface which is oriented almost perpendicular to the direction of light propagation in the optical fiber. The latter would in particular give rise to undesired back-scattering of the laser light into the optical fiber and eventually back into the source.

[0145] An optimization of light output density can be obtained in particular by providing second or more additional spiral grooves along the longitudinal axis of the optical fiber, in particular resulting in the desired more uniform and dense radiation along the longitudinal axis of the core, said grooves extending through said optical cladding into said core, successive grooves of the respective spiral grooves are alternating along the longitudinally extending outer surface of the core and its optical cladding.

[0146] Preferably, the additional second or more spiral grooves alternate along the longitudinal axis of the core with the first spiral grooves on the outer surface of the core and its optical cladding, resulting in a more uniform and dense distribution of the light emitted by the grooves, so that in spite of the flank angle of individual grooves required for refracting the light propagating within the fiber optic core in generally radial directions, the laser light output may be concentrated on a shorter length of the bared distal end of the fiber core and its optical cladding.

[0147] With embodiments wherein two or more spiral grooves are provided, the starting points of the spiral grooves are preferably angularly offset in the circumferential direction of the core by 360 degrees divided by the number of grooves in the circumferential direction of the core.

[0148] This enables a uniform emission profile of the laser light which is emitted at the boundary surfaces of the grooves.

[0149] In another preferred embodiment two or more spiral grooves can have substantially the same pitch angle value relative to the longitudinal axis of the core and can further extend in the same direction. This geometry of the spiral grooves can enable a uniform emission profile of the laser light and is additionally easy to produce according to the symmetric and / or regular geometry of the grooves.

[0150] Alternatively or additionally, two or more spiral grooves can have the substantially same pitch angle value, wherein they extend in opposite directions, such that successive grooves of the respective pairs of the spiral grooves cross each other.

[0151] The double helical and / or spiral configuration of the grooves may ensure a uniform and / or a complete - in particular even around 360 degree - treatment of the vein and / or vessel. A double helix groove configuration consists of two congruent helices in particular with the same axis that differ by translation along the axis.

[0152] Furthermore, the pitch angle value of the spiral grooves, relative to the longitudinal axis of the core, is selected, in particular, to be about 60 degrees. In experiments that have been carried out with regard to the present invention it has been found that the pitch angle of the spiral grooves of about 60 degrees enables a uniform emission profile which is in particular required and / or advantageous for the use in medical application "phlebology" or photodynamic therapy.

[0153] The depth of the imperfections / grooves increases preferably in the direction to the distal end of the core to obtain a more uniform light distribution. In addition, the invention relates to a method for production of a device for treatment of body tissue according to one of the above-mentioned embodiments.

[0154] According to the inventive method, a sliding layer is applied, in particular coated or embedded and / or in particular by brushing, dipping, immersing and / or extruding, on and / or in an outer surface of the diffuser, preferably on and / or in the protection means and / or the cap, at least in certain regions, preferably in the region of the distal end of the diffuser, preferably the protection means and / or the cap, in particular completely, in particular to reduce friction with and / or to in particular to reduce adhesion to said surrounding tissue.

[0155] It is to be understood that reference is made to the previous remarks regarding the inventive device which also apply in the same way to the inventive process and / or method. To avoid unnecessary explanations, reference is made to the aforementioned comments on the preferred embodiments of the inventive device.

[0156] The inventive method can enable the application of the sliding layer. Thus, an improved gliding of the device can be ensured.

[0157] In a preferred embodiment of the method according to the invention the outer surface of the optical cladding is fused in the region - at least partially - between the imperfections to the inner surface of the cap, in particular the inner diameter of the cap. Alternatively or additionally, the outer surface of the optical cladding extending over a distance in front and / or behind the region provided with the imperfections is fused to the inner surface, in particular the inner diameter, of the cap.

[0158] Preferably, the fusing of the cap and the cladding is carried out before applying the sliding layer. Thus, the sliding layer is not influenced by the fusing process.

[0159] The preferred fusing can ensure the material-locking connection between the cladding and the cap. Accordingly, the safety for the patient during the medical treatment with the device is increased. Preferably, the cap cannot be pulled off the cladding and / or the core during the treatment of the body tissue, in particular when the device is in the vessel and / or in the vein.

[0160] A vacuum according to the invention is in particular to be understood as a partial vacuum that can be reached in a laboratory, wherein in the partial vacuum is negative pressure. In particular, as a "vacuum" a low vacuum up to an ultra-high vacuum is to be understood according to the invention.

[0161] Preferably, the light diffuser, more preferably the cap and / or the cladding, is heated at least in the regions to be fused, in particular so that the cap at least partially collapses and is fused to the optical cladding and / or the core. A vacuum can be applied to the still open end of the cap before and / or during the heating, in particular so that the cap can collapse to the cladding and / or core in a vacuum environment.

[0162] The material of the cap, in particular glass and / or fused silica, can be fused due to the heating of the cap and / or the cladding to the cladding and / or the core. The materials of the cap and the cladding and / or the core are firmly bonded after the cap has collapsed in the fused regions. Those regions can extend circumferentially and / or in a 360 degrees manner around the core and / or are provided partially, namely in the fused regions (partial areas). The design of the fused regions can in particular vary according to the regions that have been heated. The region in which the cap and / or cladding is heated is in particular the region in which the cap collapses on the cladding and can therefore be the so-called "fused region" in which the cap is in particular inseparably connected to the cladding and / or the core.

[0163] In a further preferred embodiment of the present invention, preferably before applying the sliding layer and / or in particular before fusing the outer surface of the cladding to the inner diameter of the cap, a part of the protective sheath from the distal end of the wave guide is removed, preferably the part being longer than the length of the section of the core and its cladding to be provided with the imperfections, in particular the grooves or perturbation centers.

[0164] Alternatively or additionally, preferably before applying the sliding layer and / or in particular before fusing the outer surface of the cladding to the inner diameter of the cap, a part of the outer sheath of the protective sheath is removed. The removal of the protective sheath and / or the outer sheath of the protective sheath can in particular be carried out before the cap is fused to the cladding. It is also possible that the sheath and / or the outer sheath is removed after the cap is fused to the cladding and / or the core. The removal of the protective sheath enables the arrangement of the cap over the cladding. The protective sheath can be provided to protect the core during the use and / or the transport. Moreover, according to the method of the present invention, the reflector at the distal end of the bared core and its cladding can be provided, in particular by removing the material of the core and / or the cladding. The removing of the material of the core and / or cladding can be carried out before the cap is fused to the cladding.

[0165] The removal of the material of the core and / or the cladding can be carried out in such a way that the reflector is designed as a reflecting cone. The cone angle of the reflecting cone can vary between 60 to 90 degrees. The geometry of the reflecting cone of the reflector can further influence the refraction and / or reflection behavior of the light that hits the reflector. Either a reflection, in particular a total internal reflection, or a refraction of the laser light is to be caused. It may be the case, that both - a reflection and a refraction - occurs with regard to the attack angle and / or the angle of incidence of the laser light.

[0166] In addition, the imperfections, preferably the grooves or perturbation centers, can be formed by cutting them through the optical cladding, in particular into the core, by means of a CO2 laser beam and / or a plasma beam and / or a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm.

[0167] The size and / or pattern of the imperfections can vary along the length of the core. It may be the case, that a first type of the imperfections only extends into the cladding, wherein another type of imperfections extends into the cladding as well as into the core. Both types of imperfections can be achieved by cutting them with the CO2 laser beam.

[0168] The Femtosecond pulse laser is preferably used to provide the perturbation centers into the wave guide, preferably within the core, the core and the cladding or only within the cladding.

[0169] The core and its optical cladding can be rotated around its longitudinal axis relative to the laser beam, preferably thereby cutting the imperfections. Further, the laser beam and / or the wave guide and the core and the optical cladding thereof are axially moved along the longitudinal axis of the core in a synchronized manner with the rotation of the core. In this way the imperfections can be provided. Preferably, the protection means is slid over the distal end of the wave guide, preferably is also slid onto a short length of the buffer layer from which the outer sheath, in particular outer layer of the protective sheath, was removed.

[0170] Furthermore, the cap is in particular slid over the region provided with the imperfections of the core and cladding, preferably is also slid onto a short length of the buffer layer from which the outer sheath, in particular the outer layer of the protective sheath, was removed.

[0171] Therefore, the buffer layer can surround the core and / or the cladding before the cap is provided. Alternatively, a buffer layer can be provided after the cap has been slid over the cladding and / or the core. In another embodiment, there is no buffer layer, wherein the cap is connectable to the outer layer / outer sheath of the protective sheath after the cap is preferably fused to the cladding.

[0172] In particular, the proximal end of the cap can be glued to the protective sheath, preferably the buffer layer and / or the outer sheath, after the cap is fused to the core and / or the cladding.

[0173] Preferably, the cap can be glued by inserting the device and / or the diffuser comprising the cap with the distal end of the wave guide contained therein through an annular seal at the top of a vacuum tight container having a glue filled flask at the bottom thereof and by applying at least a partial vacuum within the container and / or by introducing the device and / or the diffuser up to beyond the distal end of the cap into the glue filled flask.

[0174] The vacuum can be released from the container so that the glue from the flask Is sucked into, preferably any, gap(s) between the cap, the buffer layer and the unfused proximal end of the core and its cladding. Alternatively or additionally, the glue is shaped and, preferably, bridges the proximal end of the cap and the outer layer / outer sheath of the protective sheath and, more preferably, any glue still adhering to the outer surface of the cap is removed.

[0175] Therefore, the cap can be glued to the outer sheath of the protective layer after the cap is fused to the cladding and / or the core. The gluing of the cap to the buffer layer and / or the outer sheath can be reached by inserting the wave guide and the cap in a glue filled flask. The gluing of the cap to the outer sheath is a further possibility for connecting the cap to the core. In addition, the glue between the outer sheath and the cap ensures that no liquid, in particular no blood, can reach the boundary between the core and the cladding and / or the cap. In particular, the cap is connected to the outer sheath in a liquid tight and / or fluid tight manner so that no liquid can reach the inner surface of the cap.

[0176] Further, a smooth transition of the cap to the outer sheath is provided so that injuries of the body tissue during or after the treatment of the body tissue can be avoided for the reason that there are no sharp edges and / or sharp corners at the proximal end of the cap.

[0177] Furthermore, it is clear that in the aforementioned intervals and ranges all interim intervals and individual values are comprised and must be considered as essential for the invention, even if these interim intervals and individual values are not specifically provided.

[0178] Further features, advantages, and application possibilities of the present invention are provided in the following description of exemplary embodiments shown in the drawing. All described and / or illustrated features form, by themselves or in any combination, the object of the present invention, regardless of their summary in the claims and their dependencies.

[0179] Preferred embodiments of the device according to the present invention are shown in the enclosed drawing, wherein:

[0180] Figure 1 shows a first embodiment of the diffuser device of the present invention in a schematic cross-sectional side view;

[0181] Figure 2 shows a detail marked in Figure 1 ;

[0182] Figure 3 shows a non-limiting detail of a grooved section of the diffuser device and the method of cutting the grooves;

[0183] Figure 4 shows a second embodiment of the diffuser device of the present invention in a schematic cross-sectional side view; Figure 5 shows a detail marked in Figure 4;

[0184] Figure 6 shows a schematic cross-sectional side view of the distal end of the diffuser according to another embodiment of the inventive device;

[0185] Figure 7 shows a schematic cross-sectional side view of the distal end of the diffuser according to another embodiment of the inventive device;

[0186] Figure 8 shows a schematic cross-sectional side view of the distal end of the diffuser of another embodiment of the inventive device;

[0187] Figure 9 shows a schematic perspective side view of the core according to another embodiment of the inventive device;

[0188] Figure 10 shows a schematic perspective side view of the core according to another embodiment of the inventive device;

[0189] Figure 11 shows a schematic perspective side view of the core according to another embodiment of the inventive device;

[0190] Figure 12 shows a schematic cross-sectional side view of the distal end of the diffuser of the inventive device according to another embodiment;

[0191] Figure 13 shows a cross sectional side view of the core and the cladding;

[0192] Figure 14 shows a schematic perspective side view of the core and the cladding according to another embodiment of the inventive device;

[0193] Figure 15 shows a schematic process scheme of the inventive method;

[0194] Figure 16 shows a schematic cross sectional view on the layer structure of a further embodiment of the diffuser according to the invention;

[0195] Figure 17 shows a schematic cross sectional view of a further embodiment of the diffuser according to the invention; Figure 18 shows a schematic cross sectional view of a further embodiment of the diffuser according to the invention;

[0196] Figure 19 shows a schematic cross sectional view of a further embodiment of the diffuser according to the invention;

[0197] Figure 20 shows a schematic cross sectional view on the layer structure of a further embodiment of the diffuser according to the invention;

[0198] Figure 21 shows a schematic cross sectional view of a further embodiment of the diffuser according to the invention;

[0199] Figure 22 shows a schematic cross sectional view of the wave guide;

[0200] Figure 23 shows a schematic diagram illustrating a first method of forming a plurality of perturbation centers inside a wave guide according to the invention;

[0201] Figure 24 shows a schematic diagram illustrating three concentric circles of perturbation centers being formed inside a wave guide by the first method of Fig. 23;

[0202] Figure 25 shows a schematic diagram illustrating two triangular arrays of perturbation centers being formed inside a wave guide while arranging the two arrays to be symmetrical to the axis of the wave guide by the first method of Fig. 23;

[0203] Figure 26 shows a schematic diagram illustrating a second method of forming a plurality of perturbation centers inside a wave guide according to the present invention;

[0204] Figure 27 shows a schematic diagram illustrating two radial-distributed concentric circles of perturbation centers being formed inside a wave guide by the second method of Fig. 26; and Figure 28 shows a schematic diagram illustrating a third method of forming a plurality of perturbation centers inside a wave guide according to the present invention.

[0205] In the figures, which are only schematic and sometimes not to scale, the same reference signs are used for the same or similar parts and components, corresponding or separable properties and advantages being achieved even if these are not repeatedly described.

[0206] Figure 6 shows a distal end of the device 17 and / or the diffuser 13 for treatment of a body tissue. A device 17 and / or a diffuser 13 for the treatment of body tissue is shown in Figure 1. The device 17 and / or the diffuser 13 can be used for the permanent occlusion of varicose veins, preferably in the lower limbs, and / or for the medical application phlebology and / or for the permanent occlusion of varicocele and / or vascular malformations and / or for the use in aesthetic surgeries, preferably laser assisted lipolysis, and / or for tumor treatment by means of laser induced thermotherapy and / or photodynamic therapy. Alternatively or additionally, the device 17 can be used in particular for the irradiation of brain tissue, for ear-nose-throat applications, in particular necrosis of tissue, for surface disinfection by laser light, for dermatologic treatment, including application on skin and / or nails and / or for treatment of pilonidal sinus, anal fistula and / or hemorrhoids.

[0207] The device 17 and / or the diffuser 13 can be at least partially inserted in the body tissue, in particular in the vessels and / or the veins.

[0208] The device 17 for the treatment of body tissue has a light diffuser 13 for irradiating said tissue by laser light energy and / or by electromagnetic radiation, wherein the light diffuser 13 is designed to irradiate the radiation laterally with respect to a longitudinal center axis of the light diffuser 13 and endoluminally.

[0209] Further, Fig. 1 shows that a sliding layer 51 is provided on an outer surface of the distal end of the diffuser 13. In the embodiment shown in Fig. 1 , the sliding layer 51 does not enclose a tip of the distal end of the diffuser 13, but is provided at least partially in the region A (active region A), namely the region in which the radiation energy, preferably the laser light, is irradiated. However, in the embodiment shown in Fig. 4 the sliding layer 51 not only encloses the region A but also the tip of the distal end of the diffusor 13. In particular, the sliding layer 51 can cover the outermost tip of the diffusor 13, but not has to cover it. The sliding layer 51 further can form the outermost layer of the diffusor 13 at least in the area which is covered with this sliding layer 51. Therefore, the sliding layer 51 is preferably not covered with another layer of the diffusor 13 at its outer surface which is directed to the tissue during the treatment with the device 17.

[0210] The sliding layer 51 can be applied to the outermost surface of the diffuser 13 which can be a cap 7, as shown in Fig. 1 , but not has to be.

[0211] The sliding layer 51 is provided at least in certain regions, preferably in the region of the front distal end of the diffuser 13, as shown in the Fig. 4 and 5, and / or in the region A of the energy emission of the diffuser 13, which is shown in Fig. 1 . Preferably, the sliding layer 51 covers completely the front distal end of the diffuser 13 and / or the region of the energy emission.

[0212] The sliding layer 51 can reduce friction during the treatment with the device 17.

[0213] Preferably, the diffuser 13 irradiates circumferentially and endoluminally said tissue by laser light energy.

[0214] Fig. 1 shows that said diffuser 13 is connected at its proximal end to a source 10 of laser light energy by a preferably flexible wave guide 12 comprising a fiber optic core 1 covered by an optical cladding 2 having a refractive index smaller than that of the core 1 . The wave guide 12 can be an optical fiber.

[0215] In Figure 6 the wave guide 12, namely the distal end of the wave guide 12, is shown with its core 1 and its optical cladding 2.

[0216] Figure 6 shows that in the cladding 2 and / or in the core 1 and / or in a boundary between the core 1 and the cladding 2 imperfections 18 are provided, which are designed as recesses and are adapted to direct the light, preferably to refract and / or reflect the light propagating within the core 1 and / or its optical cladding 2 in generally radial directions. The refractive index of the cladding 2 is smaller than that of the core 1 so that the light propagates through the core 1. The imperfections 18 create boundary surfaces on which the laser light is refracted and / or reflected. These boundary surfaces can influence the propagation behavior of the laser light. Further, over and / or by the imperfections 18 the laser light is (partially) sent out and / or coupled out so that a, in particular specified, percentage of the intensity of the laser light can be transmitted and can "hit" the body tissue.

[0217] Moreover, Figure 6 shows that a cap 7 is provided which is transparent to the laser light enclosing the distal end of the core 1 and its optical cladding 2 in a fluid tight and / or liquid tight manner. The cap 7 can surround the cladding 2 and the core 1 at the distal end of the wave guide 12. The cap 7 can be inserted in the body tissue, wherein the laser light is transmitted via the cap 7. The refractive index of the cap 7 is of such a size that with regard to the refractive index of the core 1 and the cladding 2, the laser light can pass the cap 7 to be sent out and / or to be emitted and / or to be coupled out by the diffuser 13. Also, the cap 7 protects the core 1 and the cladding 2 from the liquid, in particular the blood, in the body tissue. Moreover, the cap 7 can increase the stability of the distal end of the diffuser 13 which is inserted in the body tissue.

[0218] According to the embodiment shown in Fig. 4 the sliding layer 51 is formed as a coating of the diffuser 13, namely in particular on the outer, exterior surface of the diffuser 13. It is not shown that the sliding layer 51 is formed as a sliding agent, in particular on the exterior and / or outer surface of the diffuser 13.

[0219] The sliding layer 51 can be formed as a single, continuous layer or can comprise several areas which each can comprise a part of the sliding layer 51 . In further embodiments, the sliding layer 51 can thus be composed of a plurality of sub-areas, wherein the sub-areas can be connected to one another, but do not have to be connected. Particularly preferably, the sliding layer 51 has a continuous and uninterrupted layer, which can extend over the foremost tip of the diffuser 13, but does not have to extend. Fig. 1 shows that the sliding layer 51 is a coherent layer, which is in particular sleeve-shaped, but does not extend over the foremost tip of the diffuser 13. Fig. 4, on the other hand, shows that the front tip of the diffusor 13 is enclosed.

[0220] It is not shown that the sliding layer 51 can comprise and / or consist of a plastic material and / or that the sliding layer 51 can comprise and / or consist of a material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroeth- ylene, polysiloxane, higher order polysiloxane and mixtures thereof, and / or that the material of the sliding layer 51 can comprise silicone or can consist of silicone.

[0221] The source 10 of the laser light and / or the electromagnetic radiation can be a part of the device 17, but does not have to be. If the source 10 is not part of the device 17, the diffuser 13 can be characterized in that it is connectable to the source 10.

[0222] The laser light energy and / or the electromagnetic radiation provided by the source 10 can have a wavelength of (1450 + / - 30) nm, (1950 + / - 40 nm) and / or a wavelength between 2700 nm to 3100 nm, preferably a wavelength of (2770 + / - 40 nm) and / or (2900 + / - 40) nm, and / or a wavelength of (6100 + / - 40) nm. The aforementioned wavelengths enable a good absorption of the radiation energy in water and therefore an effective treatment of the human tissue which is mainly composed of water.

[0223] The wave guide 12 shown in Fig. 2 has at least one radiation emitting surface which is designed to emit the radiation laterally with respect to a longitudinal center axis of the light diffuser 13 and endoluminally. In the embodiment shown in Fig. 2 the radiation emitting surface can be formed by an imperfection 18 which is designed as a groove 5. In other embodiment the radiation emitting surface can be designed according to the imperfections 18.

[0224] Fig. 18 shows that the distal end of the diffuser 13 comprises a protection means 52 which encloses at least a protection part of the wave guide 12, preferably a part of an energy emitting segment and / or a part of a segment comprising the radiation emitting surface or surfaces, more preferably the whole length of the energy emitting segment and / or the whole length of the segment comprising the radiation emitting surface or surfaces, and / or a part of the region A which has been discussed above.

[0225] The protection means 52 can be formed by different parts of the diffusor 13. Further, the protection means 52 can enclose the front tip of the diffuser 13, but not has to cover it. Moreover, the protection means 52 can be the outer layer on which preferably at least in certain areas the sliding layer 51 can be provided, but not has to be outer layer of the diffuser 13. Alternatively or additionally, the protection means 52 can be designed as a sliding layer 51 so that in particular no additional application of the sliding layer 51 is necessary.

[0226] Fig. 16 shows the layer structure of the diffusor 13. However, only a part of the diffuser 13 is shown, namely the upper part. The diffuser 13 has been divided in its center, in particular along its central longitudinal axis, so that the layer structure can be seen for reasons of clarity. Figs. 17 to 20 also show that the diffuser 13 is only shown in part, namely with its upper half, and has been divided along its central longitudinal axis.

[0227] The arrow shown in Fig. 16 visualizes the direction of the radiation energy and / or of the laser light starting from the source 10 (not shown in Fig. 16) to the distal end of the diffuser 13 (not shown in Fig. 16) and / or in the direction of the patient's area of application (tissue).

[0228] Fig. 16 also shows that the sliding layer 51 is made up of several parts. In the illustrated embodiment example according to Fig. 16, it consists of a protection sheath 25 and its outer sheath 14. The outer sheath 14, which can also be formed as sliding layer 51 , is optional. A protection means 52 is not necessarily present in this embodiment, but can optionally be formed by any of the layers, preferably by a buffer layer 3.

[0229] Fig. 17, on the other hand, shows that a protection means 52 is provided. In the embodiment example shown in Fig. 17, this is formed by a cap 7. The cap 7 can also be formed as a sliding layer 51 , at least in some areas, in particular completely.

[0230] Fig. 18 shows that the cap 7 is designed as a protection means 52. The sliding layer 51 is applied to the cap 7 and encloses not only the region A but also the front tip of the diffuser 13.

[0231] Fig. 19 shows that although the cap 7 is also designed as a protection means 52, the sliding layer 51 does not enclose the front tip of the diffuser 13 but is arranged in particular in the area of the radiation emission surface and therefore covers the region A at least partially, preferably completely. In Fig. 20, a further embodiment shows that the buffer layer 3 is designed as a protection means 52 and also simultaneously as a sliding layer 51. However, the buffer layer 3 does not have to enclose the front tip of the diffuser 13.

[0232] It is not shown that the energy emitting segment and / or the segment comprising the radiation emitting surface or surfaces and / or the region A has a length up to 10 cm, preferably a length between 0,1 to 100 cm, more preferably between 1 to 50 mm, in particular between 3 to 4 mm.

[0233] As described above the protection means 52 can be a part of the wave guide 12 or is connected to the wave guide 12, preferably in a fluid tight and / or liquid tight manner. The buffer 3 can be a part of the wave guide 12, wherein the cap 7 is connected to the wave guide 12, but is not part of the wave guide 12. The cap 7 is a part of the diffusor 13. Both - the cap 7 and the buffer layer 3 - can be designed as the protection means 52 in different embodiments.

[0234] Fig. 19 shows that the protection means 52 comprises the outer surface, in particular the outermost surface, of the diffuser 13, the protection means 52 also encloses the protection part in a fluid tight and / or liquid-tight manner. It has to be understood that the sliding layer 51 can be applied on the outer surface and afterwards the outer surface is not the outermost surface of the diffuser 13. In the embodiment shown in Fig. 19 the cap 7 is attached to the wave guide 12 in a fluid tight manner and is further designed as the protection means 52.

[0235] Therefore, the protection means 52 can either be designed as a coated layer of the wave guide 12, a protective sheath 25 and / or an outer sheath 14 of the protective sheath 25 of the wave guide 12 or the protection means 52 is designed as a cap 7, enclosing the distal end of the wave guide 12, as shown in Fig. 19.

[0236] In particular, the cap 7 is a fused silica cap.

[0237] In other embodiments the cap 7 comprises and / or consists of a plastic material and / or the cap 7 comprises or consists of a material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroethylene, polysiloxane, higher order polysiloxane and mixtures thereof, and / or the material of the cap 7 comprises silicone or consists of silicone. The protection means 52 shown in Fig. 19 is transparent to the radiation energy. In other embodiments, the protection means 52 is translucent - also with an embodiment shown in Fig. 19. However, the protection means 52 shown in Fig. 20 can be translucent or transparent to the radiation energy in particular emitted by the diffuser 13.

[0238] Fig. 1 shows that the sliding layer 51 is provided at least partially on the outer surface of the protection means 52. In further, not shown embodiments the sliding layer 51 can be additionally provided to the protection means 52 and further covers the protection means 52 completely.

[0239] Further, Fig. 1 shows that the sliding layer 51 is provided at least in certain regions, preferably in the region in the outermost distal end of the protection means 52, preferably completely, on the protection means 52.

[0240] As described above, the protection means 52 can be designed as the sliding layer 51.

[0241] The sliding layer 51 is preferably transparent or translucent for the emitted laser energy.

[0242] The thickness of the sliding layer 51 can vary. In the illustrated embodiments the sliding layer 51 has a material thickness of at most 0.5 mm, preferably at most 0.1 mm, more preferably at most 0.05 mm, in particular between 0.01 mm to 0.1 mm.

[0243] It has already been described that the imperfections 18 can be designed either as one or several recess(es).

[0244] However, in Fig. 20 is shown that the imperfections 18 can also be designed as one or several perturbation center(s) 53 and adapted to direct the electromagnetic radiation, preferably to refract and / or reflect the laser light energy propagating within the core 1 and / or its cladding 2 in generally lateral, preferably radial, directions. Further, Fig. 20 shows that the perturbation centers 53 are implemented as local variations in the refractive index of the material of the core 1 and in the cladding 2. In further, not shown embodiments the perturbation centers 53 are designed as scattering centers, voids, and / or bubbles, in particular designed as micro-cracks or material impurities. Moreover, Fig. 20 shows that the imperfections 18 are designed as perturbation centers 53 which are aligned in groups or patterns along the longitudinal extension of the wave guide 12.

[0245] It is further shown in the figures 23 to 28 that the layout of multiple perturbation centers 53 can take form of one or several geometries, in particular as circle, spiral, line and / or cuboid. Thus, preferably each geometry of the perturbation centers 53 can be oriented along or orthogonally with respect to the longitudinal extension of the wave guide 12. In particular, the geometries of the perturbation centers 53 are different or repeat within the area provided with the imperfections 18.

[0246] In a further embodiment which is illustrated for example in the figures 24 and 25, the perturbation centers 53 are only provided and / or located in the fiber core 1 , preferably only in the innermost cross-section of the fiber core 1 defined by the radius range from 0 to 80% of the fiber core 1 , more preferably defined by the radius range from 0 to 60 % of the fiber core 1 , in particular defined as the radius range from 0 to 40% of the fiber core 1 , in particular each starting from the center of the fiber core 1 . The radius range of the fiber core 1 is illustrated in Fig. 22.

[0247] Fig. 23 shows a cylindrical thread, wave guide 12, with an axis D, in particular the central and / or middle axis, extending along the Y-axis. This is defined by the X-axis, Y-axis and Z-axis in a Cartesian coordinate system. A lens set 54 is fixedly positioned above the wave guide 12 at a location defined by the Z-axis. The laser beam 55 is directed downward along the Z-axis to focus on the core 1 . The lens set 54 is driven to move in two dimensions along the X- and Y-axes, forming a two-dimensional matrix of perturbation centers 53 on the core 1 . Similarly, the two-dimensional matrix of perturbation centers 53 can be formed by fixing the lens set 54 in place while enabling the wave guide 12 to perform the two-dimensional movement. In another preferred embodiment, the lens set 54 is fixedly positioned at a position capable of directing the laser beam 55 to propagate along a Y-axis direction parallel to the axis D of the wave guide 12 and focus upon the core 1. The lens set 54 can be driven to perform a two-dimensional movement with respect to the X- and Z-axis, forming an array of perturbation centers 53 with respect to a specific cross-section of the wave guide 12. Fig. 24 shows three concentric circles of smaller-sized perturbation centers 53a-53c on the core 1. Fig. 25 shows two triangular arrays of perturbation centers 53 inside a wave guide 12, arranged symmetrically to the axis D of the wave guide 12.

[0248] Fig. 26 shows a wave guide 12 that is essentially a cylindrical thread with an axis D extending along the Y-axis direction defined by a Cartesian coordinate system of X-, Y-, and Z-axes. A lens set 54 is positioned above the wave guide 12 at a location defined by the Z-axis directs the laser beam 55 downward to focus on the core 1. The wave guide 12 can be rotated about its axis D, forming a plurality of perturbation centers 53 radially distributed around the axis D. Furthermore, by modifying the focal point of the lens set 54, another ring of radially distributed perturbation centers 53 can be formed, as illustrated in Fig. 27. Similarly, rings of perturbation centers 53, 53a can be formed by fixing the wave guide 12 in place while enabling the lens set 54 to revolve around it. It should be noted that different distributions and circular alignments of the perturbation centers 53 can be achieved with respect to the various methods used to form these microstructures.

[0249] As shown in Fig. 28, the plural spiral-aligned perturbation centers 53 are formed by simultaneously driving the lens set 54 and / or the wave guide 12 to move and / or rotate

[0250] In particular, it is imperative to note that regardless of the method used to activate the wave guide 12 and lens set 54, the laser beam 55 is consistently focused on the core 1 , without any damage to the cladding 2.

[0251] The focusing depth and focus position of the laser beam 55 into the core 1 may be varied my moving and tilting the lens set 54, though, and rotation of the wave guide 12 about its axis D may become obsolete even for circular patterns if the entire core diameter can be accessed from only one side via appropriate selection and modification of the focus point depth.

[0252] In Fig. 1 and also in other illustrated embodiments it is shown that the distal end of the diffusor 13, in particular the end of the cap and / or protection means 52, and / or the outermost surface of the diffusor 13 is rounded. In other embodiments the distal end of the diffusor 13, in particular the end of the cap and / or protection means 52, and / or the outermost surface of the diffusor 13 is thickened, widened and / or conical shaped.

[0253] Figure 6 shows - in a schematic view - that the outer surface 19 of said optical cladding 2 is fused in the region A between said imperfections 18 to the inner surface, preferably the inner diameter, of the cap 7. The region A between the imperfections 18 is fused to the inner surface 21 of the cap 7 in such a way that the cap 7 is irre- movably connected to the cladding 2.

[0254] Furthermore, the outer surface 19 of the optical cladding 2 extending over a distance in front and / or behind (with regard to the direction of the light propagation in the core 1 ) the region A provided with the imperfections 18 can also be fused to the inner surface 21 , in particular the inner diameter, of the cap 7.

[0255] The cladding 2 is at least fused in one region (fused region 32) to the inner surface 21 of the cap 7. The fused region(s) 32 can be at least a part of the region A between the imperfections 18 and / or of the region C in front and / or of the region B behind the region A provided with the imperfections 18.

[0256] Figure 6 shows that at least a part of the region B behind the region A provided with the imperfections 18 is fused to the inner surface 21 of the cap 7.

[0257] Figure 7 shows that the region C in front of the imperfections 18 is fused - at least partly - to the inner surface 21 of the cap 7.

[0258] Figure 8 shows that the region C in front of the region A provided with the imperfections 18 is at least partly fused to the inner surface 21 of the cap 7, wherein also a fused region 32 is provided in the region B behind the region A provided with the imperfections 18.

[0259] It has to be understood that the Figures 6, 7, 8 and 12 show the fused region 32 in a schematic view due to the fact that the thickness of the fused region 32 is shown in an enlarged view.

[0260] The region B is in the figures referring to a region of the core 1 and / or the cladding 2 behind the region A provided with the imperfections 18, wherein in the region B the reflector 6 is in particular not included.

[0261] The region C is in particular indicating a region in front of the region A provided with the imperfections 18. The region C can extend from the "beginning" - with regard to the laser light propagation - of the region A to the proximal end of the cap 7 and / or to the outer sheath 14 or can refer to a part of the region in front of the region A provided with the imperfections 18.

[0262] That the region C refers to a part of the region in front of the region A provided with the imperfections 18 is indicated in Figure 12. The region C refers at least to a part / area / region in front of the region A provided with the imperfections 18.

[0263] The fused region(s) 32 can be in the region A, B and / or C. It has to be understood that the fused region(s) 32 can be at least a part of the region A, B and / or C. In the fused region(s) 32 the outer surface 19 of the cladding 2 is fused to the inner surface 21 of the cap 7, in particular to firmly attach the cap 7 to the cladding 2.

[0264] Further, Figure 12 shows a partial area of the region in front of the region A which is free from a fused region 32 (has a non-fused region), in particular for being filled with glue 9 to be attached to the outer sheath 14.

[0265] In particular, the outer surface 19 of the optical cladding 2 is fused continuously and / or circumferentially and / or fully in the region A between the imperfections 18 to the inner surface 21 , in particular the inner diameter, of the cap 7 and / or the outer surface 19 of the optical cladding 2 extending over a distance in front and / or behind the region A provided with the imperfections 18 is fused continuously and / or circumferentially and / or fully to the inner surface 21 , in particular the inner diameter, of the cap 7 (that means in the region B and / or in the region C). The circumferential fusing of the cap 7 to the cladding 2 can therefore be designed in a 360 degree circumferential manner.

[0266] Moreover, it is not shown in the figures that the outer surface 19 of the optical cladding 2 can be fused partially, preferably in a point-like manner and / or with longitudinal welds and / or with a patterned structure, in the region A between said imperfections 18, to the inner surface 21 of the cap 7 and / or in the region B behind the region A provided with the imperfections 18 and / or in the region C in front of the region A provided with the imperfections 18.

[0267] Also a combination of a circumferentially and / or fully fusing of the cap 7 to the cladding 2 at least in one part of a region A, B, C and a partly fusing of the cap 7 to the cladding 2 in at least one part of the regions A, B, C is possible. In particular, the cladding 2 is fused to the cap 7 in such a way that the cladding 2 and the cap 7 are firmly bonded, namely in a material-locking manner. This can be provided at least in one part of the regions A, B, C, namely in the fused region(s) 32.

[0268] Figure 13 shows that the core 1 has an outer diameter 22 between 100 and 1000 pm and in particular between 350 and 650 pm. The cladding 2 can have an outer diameter 23 between 110 and 1200 pm and in particular between 400 and 720 pm. In the embodiment according to Figure 13 the sheath thickness 24 of the cladding 2 is between 1 to 40 %, in particular between 5 to 15 %, of the outer diameter 22 of the core 1. Preferably, the sheath thickness 24 of the cladding 2 is around 10 % of the outer diameter 22 of the core 1 .

[0269] Figure 1 , Figure 12 and Figure 4 show the protective sheath 25. The protective sheath 25 can be at the distal end of the wave guide 12. The protective sheath 25 can comprise at least one buffer layer 3 adjacent to the optical cladding 2 of the core 1 and / or an outer sheath 14, also referred to as jacket. The outer sheath 14 (jacket) can prevent the breaking of the underlying structures, in particular the core 1 , during the use and transport of the wave guide 12. Furthermore, the protective sheath 25 and / or the outer sheath 14 (jacket) can be designed as a, preferably extruded, plastic coating.

[0270] The buffer layer 3 can be additionally provided to the outer sheath 14. In Figure 1 an embodiment is shown which comprises the buffer layer 3 as a part of the protective sheath 25. In the embodiment according to Figure 12 there is no need for a buffer layer 3.

[0271] Fig. 21 shows that the buffer layer 3 extends into the interior of the cap 7 and is in particular longer than the outer sheath 14 and / or the protective sheath 25 and / or extends over the outer sheath 14 and / or the protective sheath 25.

[0272] The protective sheath 25 and / or the outer sheath 14 can be joined to the cap 7, which is shown in Figure 1 , 4, and 12.

[0273] Figure 12 shows that the protective sheath 25 and / or its outer sheath 14 is at least partially removed at the distal end of the wave guide 12 to bare the core 1 and its optical cladding 2. Figure 6 shows that the imperfections 18 extend into the cladding 2, preferably to bare the core 1. The "first" imperfection 18 (with regard to the direction of the light propagation in the core 1 ) in the embodiment shown in Figure 6 extends at least into the cladding 2. Additionally, the imperfections 18 can extend also into the core 1, namely in particular in the outer circumference of the core 1. The form and depth of the imperfections 18 can influence the propagation behavior of the light. The light can be refracted on the boundary surface created by the imperfections 18. The laser light refracted on the boundary surface of the imperfections 18 can be transmitted via the cap 7.

[0274] In the Figs. 17 to 19 it is shown for different embodiments of the device 17 that the protective sheath 25 and in particular its outer sheath 14, which can be optional and / or an additional layer of the protective sheath 25 which thus can have a multilayer structure, is provided additionally to the protection means 52. On the other hand, in further embodiment the protective sheath 25 is designed as the protection means 52 or as a part of the protection means 52.

[0275] Figure 12 shows that the laser light (see dash-dotted lines) can be refracted on the boundary surface of the imperfections 18 and therefore be emitted and / or coupled out by the diffuser 13. It is not shown in Figure 12 that the laser light can also be reflected on the boundary surface of the imperfections 18. Generally, shape and orientation of the imperfections 18 can determine the way of interaction with the laser light, in this regard reference is made in particular to the Fig. 9 to 11.

[0276] In Figure 6, one type of the imperfections 18 extend solely into the cladding 2, wherein another type of the imperfections 18 extend into the core 1 as well as into the cladding 2.

[0277] Figures 1 to 5 show that the imperfections 18 are designed as grooves which are adapted to refract and / or reflect the light propagating within the core 1 and its optical cladding 2 in generally radial directions.

[0278] Figure 3 shows that said grooves 4, 5 comprise at least two spiral grooves 4, 5 which extend through said optical cladding 2 into said core 1. The successive grooves 4, 5 of the respective spiral grooves 4, 5 are alternating along the longitudinally extending outer surface 19 of the core 1 and its optical cladding 2. The imperfections 18 designed as grooves can also have a different form, in particular a patterned structure.

[0279] At least one groove can be designed as a circular and / or elliptical groove 26, which is for example shown in Figure 9. The circular and / or elliptical groove 26 can be circumferential around the core 1 . The circular and / or elliptical groove 26 can extend into the cladding 2 and / or into the core 1 .

[0280] In Figure 10 it is shown that at least one groove is designed essentially in the form of a spherical gap.

[0281] In Figure 11 it is shown that at least one groove is designed as a longitudinal groove 27. The longitudinal groove 27 can be placed on the outer circumference of the core 1.

[0282] In Figure 11 it is further shown that at least one groove can be designed as a broken groove 28, which includes parts that are not grooved.

[0283] It is not shown that at least one groove is a point-like groove, which forms the imperfection 18. The point-like grooves can form a uniform and / or a non-uniform patterned structure.

[0284] It is not shown that also different forms of grooves can be combined so that the wave guide 12 can comprise elliptical grooves 26, longitudinal grooves 27, spherical caps and / or point-like and / or broken grooves 28.

[0285] Figure 6 shows that the depth 30 and the width 31 of the imperfections 18 increases in the direction of the distal end of the core 1. It is not shown that also in further embodiment the depth 30 and / or the width 31 and / or the length of groups and / or arrays of aligned perturbation centers 53 can increase in direction to the distal end of the core. The increasing of the depth 30 and / or the width 31 of the imperfections 18 can be designed in such a way that the percentage of the laser light which is refracted on the imperfections 18 and therefore emitted by the diffuser 13 can be influenced. For example, the depth 30 and / or the width 31 of the imperfections 18 in the direction of the distal end of the core 1 is increased due to the fact that the "first" imperfections 18 need to refract a smaller percentage of the laser light than the imperfections 18 behind. In particular, the depth 30 and / or the width 31 can increase so that a substantially uniform emission profile can be reached, in particular over the length 29 of the region A provided with the imperfections 18.

[0286] It is not shown that the length of the imperfections 18 can increase in the direction of the distal end of the core 1 .

[0287] In particular, the depth 30 and / or the width 31 and / or the length of the imperfections 18 can increase up to 1000 %, preferably up to 800 %, more preferably up to 400 %, in particular with regard to the smallest depth 30 and / or width 31 and / or length of the imperfections 18. Preferably, the greatest depth 30 and / or width 31 and / or length of the imperfections 18 can be around two to four times higher than the smallest depth 30 and / or width 31 and / or length of the imperfections 18.

[0288] Figure 12 shows a core 1 which comprises as material fused silica, in particular quartz glass. The core 1 can comprise optical fibers which can comprise as a material fused silica / quartz glass. The cladding 2 can also contain fused silica as a material, in particular quartz glass. The refractive index of the cladding 2 differs from that of the core 1 , wherein the refractive index of the core 1 is greater than that of the cladding 2. This can be achieved in particular by doping either the material of the core 1 and / or the material of the cladding 2. In the embodiment shown in Figure 12 the fused silica material of the cladding 2 is doped with fluorine.

[0289] In another embodiment, which is not shown, the core 1 and / or the cladding 2 can be - additionally or alternatively - be doped with germanium.

[0290] The fused silica material of the core 1 can differ from the fused silica material of the cladding 2, in particular to achieve the different refractive indices.

[0291] Alternatively or additionally, the core 1 and / or the cladding 2 in particular comprises or consists of a material selected from the group of fused silica, in particular quartz glass, chalcogenide glass, arsenic sulfide glass, silver chloride glass, silver bromide glass and mixtures thereof. The material, preferably the exact material composition, of the core 1 can differ from the material of the cladding 2, preferably to achieve a lower refractive index in the cladding 2 than in the core 1 . As mentioned above, the material of the cladding 2 and / or the core 1 is preferably doped, in particular wherein the cladding 2 is doped with fluorine and / or the core 1 is preferably doped with germanium.

[0292] In other, not shown embodiments the chalcogenide glass of the cladding 2 and / or the core 1 can be doped, wherein, preferably, at least one of the fiber core 1 and the cladding 2 is doped with germanium, selenium, silver, indium or tellurium or rare earth elements.

[0293] Furthermore, in the embodiment which is shown in Figure 6, the region A provided with the imperfections 18 can have a length 29 between 0.1 to 30 mm and in particular between 3 to 4 mm. The length 29 of the region A provided with the imperfections 18 can influence the emission profile of the laser light. In particular, the laser light is not solely sent or coupled out by the front / outer end (no front firing for the efficient use of laser energy).

[0294] Figures 9 to 11 show that the distal end of the core 1 is terminated by a reflector 6. The reflector 6 can be formed by the distal end of the core 1 and / or the cladding 2. In particular, the reflector 6 comprises as material the same material as the core 1 , wherein further the core 1 can lead into the reflector 6. The reflector 6 can be adapted to reflect the laser light energy and / or the electromagnetic radiation.

[0295] Furthermore, Figures 9 to 11 show that the reflector 6 has a conical shape and / or is designed as a cone, wherein the cone angle is smaller than 90 degrees. In particular, the cone angle can be about 60 degrees or about 55 degrees to 90 degrees. Depending on the form of the reflecting cone the laser light can be refracted and / or reflected on the boundary surface of the reflector 6. A reflection or refraction is also influenced by the angle of incidence of the laser light which hits the boundary surface of the reflector 6. Therefore, the reflector 6 can serve - in the figurative sense - as a mirror and / or in such a way that the laser light can be emitted over the distal end of the cap 7.

[0296] Thus, the term "reflector" should be understood preferably in a broader sense, where the reflector 6 can also refract light depending on cone angle, angle of incidence of the light, or the like. Figure 12 shows in a schematic view laser light (see dash-dotted lines) that hits the boundary surface of the reflector 6. For the visualization of the reflection and / or refraction of the laser light depending on the cone angle of the reflector 6 two forms of reflectors 6 are shown. The reflector 6 having a greater cone angle can lead to a reflection of the light (dashed line), wherein the laser light is refracted at the boundary surface of the reflector 6 having a smaller cone angle (dash-dotted line).

[0297] In further embodiments, the reflector 6 is in particular designed as a cone and can be shaped and / or curved inwards, facing to the distal end of the diffuser 13, or outwards, facing away from the distal end of the diffuser 13 and / or has a concave or convex design.

[0298] Figure 1 shows that the proximal end of the bore of the cap 7 is provided with a section 8 having an increased inner diameter corresponding to the outer diameter of the buffer layer 3. The increased inner diameter of the section 8 can be designed in such a way that the cap 7 can be adjoined to the outer sheath 14, in particular with glue 9.

[0299] Figure 12 shows that the proximal end of the cap 7 is provided with a section 8 having an increased inner diameter corresponding to the outer diameter 22 of the core 1 and / or the outer diameter 23 of the cladding 2.

[0300] This section 8, having the increased inner diameter, of the cap 7 can be filled with glue 9, in particular to further connect the cap 7 to the outer sheath 14 and / or to provide a smooth transition between the outer surface of the cap 7 to that of the outer sheath 14.

[0301] Furthermore, in Figure 1 it is shown that the section 8 having the increased inner diameter of the proximal end of the cap 7 is glued to at least one buffer layer 3. Further, the section 8 can alternatively or additionally be glued to the protective sheath 25 and / or to the outer sheath 14 and / or to the core 1 and / or to the cladding 2. The glue 9 can furthermore be provided to reach a smooth transition between the outer surface, in particular the outer diameter, of the cap 7. Additionally, the smooth transition can also be provided from the cap 7 to the outer sheath 14 of the protective sheath 25. In Figure 12 it is shown that the outer sheath 14 can be glued to the cap 7 at the proximal end of the cap 7 with glue 9. The cap 7 also has an increased inner diameter at the proximal end for the connection with the glue 9 and to be adjoined to the protective sheath 25, in particular the outer sheath 14 (also referred to as jacket).

[0302] In further embodiments, the proximal end of the bore of the cap 7 can be provided with a section 8 having an increased inner diameter corresponding to the outer diameter of the buffer layer 3 and / or the diameter of the outer sheath 14 and / or the diameter of the protective sheath 25.

[0303] It is not shown that the inner surface 19 of the bore of the cap 7 is provided with an anti-reflective coating, in particular to influence the light propagation behavior, in particular to increase the efficiency of the light emitting profile of the laser light.

[0304] In addition, it is shown in Figure 3 that the imperfections 18, preferably the grooves 4, 5, can be produced by cutting by means of a CO2 laser beam 20 by rotating the core 1 and its optical cladding 2 around its longitudinal axis 16 relative to the laser beam and axially moving the laser beam 20 and / or the core 1 and its cladding 2 along the longitudinal axis 16 of the core 1 in a synchronized manner with the rotation of the core 1 .

[0305] Figure 3 shows - in a schematic view - that the laser beam 20 can hit the core 1 in a respective angle. This angle can be around 70 degrees as shown in Figure 3.

[0306] It is not shown that the imperfections 18, in particular the perturbation center(s) 53, are produced by material processing by means of a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm by rotating the core 1 and its cladding 2 around its longitudinal axis 16 relative to the laser beam 20 and axially moving the laser beam 20 and / or the core 1 and its cladding 2 along the longitudinal axis 16 of the core 1 in a synchronized manner with the rotation of the core 1.

[0307] The starting points of the spiral grooves 4, 5 can be angularly offset in the circumferential direction of the core 1 by 360 degrees divided by the number of grooves. It has to be understood that the shown number of grooves is not limited to the number shown in the embodiments according to Figure 1 to Figure 14. The number of the imperfections 18 and / or the grooves 4, 5 can depend on the desired laser light emission profile.

[0308] Figure 3 shows that two or spiral grooves 4, 5 can substantially have the same pitch angle a value relative to the longitudinal axis 16 of the core 1 and can extend in the same direction.

[0309] In Figure 5 and 14 it is shown that the pitch angle a value of the spiral grooves 4, 5 is substantially the same, wherein the spiral grooves 4, 5 can extend in opposite directions such that grooves of respective pairs of the spiral grooves cross each other The crossing points are in particular shown in Figure 14 and in Figure 5.

[0310] The pitch angle a value of the spiral grooves 4, 5 can preferably be about 60 degrees relative to the longitudinal axis 16 of the core 1, as shown in Figure 3.

[0311] The invention can also relate to a method for the production of a device 17 for treatment of body tissue according to one of the aforementioned embodiments. Thus, in the method a sliding layer 51 is applied, in particular coated or embedded and / or in particular by brushing, dipping, immersing and / or extruding, on and / or in an outer surface of the diffuser 13, preferably on and / or in the protection means 52 and / or the cap 7, at least in certain regions, preferably in the region of the distal end of the diffuser 13, preferably the protection means 52 and / or the cap 7, in particular completely, in particular to reduce friction with and / or to reduce adhesion to said surrounding tissue.

[0312] Before applying the sliding layer 51 , the outer surface 19 of the cladding 2 can be fused in the region A between the imperfections 18 to the inner diameter of the cap 7 and / or the outer surface 19 of the cladding 2 extending over a distance in front and / or behind the region A provided with the imperfections 18 can be fused to the inner surface 21 , preferably the inner diameter, of the cap 7.

[0313] For the fusing step the device 17, preferably the light diffuser 13, more preferably the cap 7 and the cladding 2, can be heated at least in the regions A, B, C to be fused, in particular so that the cap 7 at least partially collapses and is fused to the cladding 2 and / or the core 1 , in particular wherein a vacuum is applied to the still open end of the cap 7 before and / or during the heating. Preferably before applying the sliding layer 51 and / or in particular before fusing the outer surface 19 of the cladding 2 to the inner diameter of the cap 7, a part of the protective sheath 25 from the distal end of the wave guide 12 is removed, preferably the part covering the length of the section of the core 1 and its cladding 2 to be provided with the imperfections 18, in particular the grooves 4, 5 or perturbation centers 53.

[0314] Alternatively or additionally, preferably before applying the sliding layer 51 and / or in particular before fusing the outer surface 19 of the cladding 2 to the inner diameter of the cap 7, a part of the outer sheath 14 of the protective sheath 25 is removed.

[0315] Further, the reflector 6 at the distal end of the bared core 1 and its cladding 2 is provided, in particular by removing the material of the core 1 and / or the cladding 2.

[0316] As it has already been described with regard to the device 17, the imperfections 18, preferably the grooves 4, 5 or the perturbation centers 53, are produced by material processing by means of a CO2 laser beam 20 or a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm. The wave guide 12 and / or the core 1 and its cladding 2 are rotated around its longitudinal axis 16 relative to the laser beam 20. Further, the laser beam 20 and / or the wave guide 12 and the core 1 and the cladding 2 thereof can be axially moved along the longitudinal axis 16 of the core 1 in a synchronized manner with the rotation of the core 1.

[0317] Preferably, the protection means 52 is slid over the distal end of the wave guide 12, preferably is also slid onto a short length of the buffer layer 3 from which the outer sheath 14 and / or the outer layer of the protective sheath 25 was removed.

[0318] Also, the cap 7 can be slid over the region A provided with the imperfections 18 of the core 1 and cladding 2, preferably is also slid onto a short length of the buffer layer 3 from which the outer sheath 14 and / or the outer layer of the protective sheath 25 was removed.

[0319] After the cap 7 is fused to the core 1 and / or the cladding 2, the proximal end of the cap 7 can be glued to the protective sheath 25, preferably the buffer layer 3 and / or the outer sheath 14. The glueing can be reached by inserting the diffuser 13 and / or the device 17 comprising the cap 7 with the distal end of the wave guide 12 contained therein through an annular seal at the top of a vacuum tight container having a glue filled flask at the bottom thereof and applying at least a partial vacuum within the container and / or by introducing the diffuser 13 and / or the device 17 up to beyond the distal end of the cap (7) into the glue filled flask. In particular, the vacuum is released from the container so that the glue 9 from the flask is sucked into, preferably any, gap(s) 15 between the cap 7, the buffer layer 3 and the unfused proximal end of the core 1 and its cladding 2. Moreover, the glue 9 can be shaped and, preferably, bridges the proximal end of the cap 7 and the outer sheath 14 and / or the outer layer of the protective sheath 25, wherein more preferably any glue still adhering to the outer surface of the cap 7 is removed.

[0320] Figure 15 shows a process scheme of the method for producing the device 17 and / or the diffuser 13, wherein the signs S1 to S6 refer to single process steps which can be carried out successively. The method is not limited to the steps S1 to S6.

[0321] A presently preferred, but not limiting, method for producing a device 17 described above may include the following steps:

[0322] Step S1 : Removing the protective sheath 25 from a distal end of the wave guide 12 longer than the length of the section of the core 1 and its cladding 2 to be provided with the imperfections 18, in particular the grooves 4, 5, and / or perturbation centers and removing a short length of the outer layer 14 of the protective sheath 25, the short length substantially corresponding to the length of the increased diameter portion at the proximal end of the cap 7.

[0323] Step S2: Providing the reflector 6 at the distal end of the bared core 1 and its cladding 2. The reflector 6 can be provided by removing the material of the core 1 and / or the cladding 2, in particular in such a way that the reflector 6 has the geometrical form of a reflecting cone, wherein the cone angle of the reflecting cone can vary between 60 degrees to 90 degrees.

[0324] Step S3: Forming the imperfections 18, in particular the grooves 4, 5, and / or perturbation centers by cutting them through the optical cladding 2 into the core 1 by means of a CO2 laser beam 20 or a plasma beam or a Femtosecond laser beam and rotating the core 1 and its optical cladding 2 around its longitudinal axis 16 relative to the laser beam 20 and axially moving the laser beam 20 and / or the wave guide 12 and the core 1 and the optical cladding 2 thereof along the longitudinal axis 16 of the core 1 in a synchronized manner with the rotation of the core 1.

[0325] Step S4: Sliding the cap 7 over the section of the core 1 and optical cladding 2 and

[0326] - optionally - onto a short length of the buffer layer 3 from which the outer layer 14 of the protective sheath 25 was removed.

[0327] Step S5: Fusing the cap 7 to the optical cladding 2 so that fused regions 32 occur between the outer surface 19 of the cladding 2 and the inner surface 21 of the cap 7.

[0328] The outer surface 19 of the optical cladding 2 can be fused in the region A between the imperfections 18 - at least partially - to the inner surface 21 of the cap 7. Alternatively or additionally, the outer surface 19 of the optical cladding 2 extending over a distance in front and / or behind the region A provided with the imperfections 18 - in particular the region(s) B and / or C

[0329] - is fused - at least partially - to the inner surface 21 of the cap 7. In the regions B and / or C the fused region(s) 32 can be designed as at least a part-region / partial area which can be provided circumferentially and / or at least as subparts / subsections (partly fused).

[0330] The fusing can be reached by applying a vacuum to the still open end of the cap 7 and heating the device 17 and / or diffuser 13 at the active region A and / or in the region (in particular region A, B and / or C) to be fused (later referred to as fused region 32) such that the cap 7 partially collapses and is fused to the optical cladding 2. Thus, fused region(s) 32 can be achieved, wherein preferably the cap 7 is fused to the cladding 2 and the core 1 between the imperfections 18, in particular the grooves 4, 5, and a short length at the front and end of the active zone “A” (region A).

[0331] Step S6 can be carried out after the cap 7 is fused to the core 1 and / or to the cladding 2 (see step S5). In step S6 the following further steps a) to e) can be carried out, preferably successively (one after another):

[0332] Step S6: a) Inserting the device 17 and / or diffuser 13 comprising the cap 7 with the distal end of the wave guide 12 contained therein through an annular seal at the top of a vacuum tight container having a glue filled flask at the bottom thereof and applying at least a partial vacuum within the container. b) Introducing the device 17 and / or diffuser 13 up to beyond the distal end of the cap 7 into the glue filled flask. c) Releasing the vacuum from the container so that the glue 9 from the flask is sucked into, preferably any, (the) gap(s) between the cap 7, the buffer layer 3 and / or the outer sheath 14 and the unfused proximal end of the core 1 and its cladding 2. d) Shaping the glue 9 bridging the proximal end of the cap 7 and the outer layer 14 (outer sheath 14) of the protective sheath 25 and removing any glue still adhering to the outer surface of the cap 7. e) Applying a sliding layer 51 , in particular by coating, embedding, brushing, immersing and / or extruding, on and / or in an outer surface of the diffusor 13, preferably on the outer surface of the cap 7. The sliding layer 51 can be applied at least in certain regions, in particular at least in the region A and / or in the region of the distal end of the diffusor 13.

[0333] Further aspects of the present invention, which can be realized independently and / or in combination with the aspects and features described above, are in particular:

[0334] 1 . Device (17) for treatment of body tissue, in particular for the permanent occlusion of varicose veins, preferably in the lower limbs, of varicocele and / or of vascular malformations and / or for the use in aesthetic surgeries, preferably laser assisted lipolysis, and / or for tumor treatment by means of laser induced thermotherapy and / or photodynamic therapy, and / or in particular for the irradiation of brain tissue, for ear-nose-throat applications, in particular necrosis of tissue, for surface disinfection by laser light, for dermatologic treatment, including application on skin and / or nails and / or for treatment of pilonidal sinus, anal fistula and / or hemorrhoids, by means of a light diffuser (13) for irradiating said tissue by laser light energy and / or by electromagnetic radiation, wherein the light diffuser (13) is designed to irradiate the radiation laterally with respect to a longitudinal center axis of the light diffuser (13) and endoluminally.

[0335] 2. Device of aspect 1 , characterized in that a sliding layer (51 ) is provided on an outer surface, in particular the outermost surface, of a distal end of the diffuser (13) at least in certain regions, preferably in the region of the front distal end of the diffuser (13) and / or in the region of the energy emission of the diffuser (13), in particular completely, in particular to reduce friction with and / or in particular to reduce adhesion to said surrounding tissue, in particular wherein the sliding layer (51) is formed as a coating of the diffuser (13) or as a sliding agent, in particular on the exterior and / or outer surface of the diffuser (13).

[0336] 3. Device according to aspect 2, characterized in that the sliding layer (51 ) comprises and / or consists of a plastic material and / or in that the sliding layer (51) comprises or consists of a material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroethylene, polysiloxane, higher order polysiloxane and mixtures thereof, and / or in that the material of the sliding layer (51) comprises silicone or consists of silicone.

[0337] 4. Device as claimed in one or more of the preceding aspects, characterized in that said diffuser (13) is connected and / or connectable at its proximal end to a source (10) of laser light energy and / or electromagnetic radiation via a flexible wave guide (12), wherein, preferably, the source (10) is part of the device (17), in particular wherein the wave guide (12) has at least one radiation emitting surface which is designed to emit the radiation laterally with respect to a longitudinal center axis of the light diffuser (13) and endoluminally and / or in particular wherein the laser light energy and / or the electromagnetic radiation provided by the source (10) has a wavelength of (1450 + / - 30) nm, (1950 + / - 40 nm) and / or a wavelength between 2700 nm to 3100 nm, preferably a wavelength of (2770 + / - 40 nm) and / or (2900 + / - 40) nm, and / or a wavelength of (6100 + / - 40) nm.

[0338] 5. Device as claimed in one or more of the preceding aspects, characterized in that the distal end of the diffuser (13) comprises a protection means (52) which encloses at least a protection part of the wave guide (12), preferably a part of an energy emitting segment and / or a part of a segment comprising the radiation emitting surface or surfaces, more preferably the whole length of the energy emitting segment and / or the whole length of the segment comprising the radiation emitting surface or surfaces.

[0339] 6. Device as claimed in one or more of the preceding aspects, characterized in that the energy emitting segment and / or the segment comprising the radiation emitting surface or surfaces has a length up to 10 cm, preferably a length between 0,1 to 100 cm, more preferably between 1 to 50 mm, in particular between 3 to 4 mm.

[0340] 7. Device as claimed in one or more of the preceding aspects, characterized in that the protection means (52) is part of the wave guide (12) or is connected to the wave guide (12) preferably in a fluid tight and / or liquid tight manner, in particular wherein the protection means (52) comprises the outer surface, in particular the outermost surface, of the diffuser (13) and / or in particular wherein the protection means (52) encloses the protection part in a fluid tight and / or liquid-tight manner.

[0341] 8. Device as claimed in one or more of the preceding aspects, characterized in that the protection means (52) is designed as a coated layer of the wave guide (12), a protective sheath (25) and / or an outer sheath (14) of the protective sheath (25) of the wave guide (12) and / or the protection means (52) is designed as a cap (7), enclosing the distal end of the wave guide (12), in particular wherein the cap (7) is a fused silica cap and / or in particular wherein the cap (7) comprises and / or consists of a plastic material and / or in particular wherein the cap (7) comprises or consists of a material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroethylene, polysiloxane, higher order polysiloxane and mixtures thereof, and / or in particular wherein the material of the cap (7) comprises silicone or consists of silicone.

[0342] 9. Device as claimed in one or more of the preceding aspects, characterized in that the protection means (52) is transparent or translucent to the radiation energy in particular emitted by the diffuser (13).

[0343] 10. Device as claimed in one or more of the preceding aspects, characterized in that the sliding layer (51 ) is provided at least partially, preferably completely, on the outer surface of the protection means (52), in particular wherein the sliding layer (51 ) is provided at least in certain regions, preferably in the region in the outermost distal end of the protection means (52), preferably completely, on the protection means (52), and / or in that the protection means (52) is designed as the sliding layer (51).

[0344] 11. Device as claimed in one or more of the preceding aspects, characterized in that the wave guide (12) comprises at least one fiber optic core (1 ) covered by at least one cladding (2) having a refractive index smaller than that of the core (1 ), in particular wherein the wave guide (12) is an optical fiber.

[0345] 12. Device as claimed in one or more of the preceding aspects, characterized in that the sliding layer (51 ) is transparent or translucent for the emitted laser energy.

[0346] 13. Device as claimed in one or more of the preceding aspects, characterized in that the sliding layer (51 ) has a material thickness of at most 0.5 mm, preferably at most 0.1 mm, more preferably at most 0.05 mm, in particular between 0.01 mm to 0.1 mm.

[0347] 14. Device as claimed in one or more of the preceding aspects, characterized in that a cap (7) which is transparent or translucent to the radiation energy enclosing the distal end of the core (1 ) and its cladding (2) in a fluid tight and / or liquid tight manner is provided.

[0348] 15. Device as claimed in one or more of the preceding aspects, characterized in that the light diffuser (13) irradiates circumferentially said tissue by laser light energy and / or electromagnetic radiation.

[0349] 16. Device as claimed in one or more of the preceding aspects, characterized in that in the cladding (2) and / or in the core (1) and / or in a boundary between the core (1 ) and the cladding (2) imperfections (18) are provided, designed either as one or several recess(es) or as one or several perturbation center(s) (53) and adapted to direct the electromagnetic radiation, preferably to refract and / or reflect the laser light energy propagating within the core (1) and / or its cladding (2) in generally lateral, preferably radial, directions, in particular the perturbation centers (53) are implemented as local variations in the refractive index of the material of the core (1 ) and / or cladding (2), scattering centers, voids, and / or bubbles, in particular designed as micro-cracks or material impurities. 17. Device as claimed in one or more of the preceding aspects, characterized in that the imperfections (18) are designed as perturbation centers (53) which are aligned in groups or patterns along the longitudinal extension of the wave guide (12), in particular wherein the perturbation centers (53) take form of one or several geometries, in particular as circle, spiral, line and / or cuboid, and / or in particular wherein each geometry of the perturbation centers (53) can be oriented along or orthogonally with respect to the longitudinal extension of the wave guide (12) and / or in particular wherein the geometries of the perturbation centers (53) are different or repeat within the area provided with the imperfections (18).

[0350] 18. Device as claimed in one or more of the preceding aspects, characterized in that the perturbation centers (53) are only provided and / or located in the fiber core (1), preferably only in the innermost cross-section of the fiber core (1 ) defined by the radius range from 0 to 80 % of the fiber core (1 ), more preferably defined by the radius range from 0 to 60 % of the fiber core (1 ), in particular defined as the radius range from 0 to 40% of the fiber core (1), in particular each starting from the center of the fiber core (1 ).

[0351] 19. Device as claimed in one or more of the preceding aspects, characterized in that the outer surface (19) of said cladding (2) is fused in or next to the region (A) of said imperfections (18) at least in parts to the inner surface (21), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused at least in parts to the inner surface (21 ), preferably the inner diameter, of the cap (7).

[0352] 20. Device as claimed in one or more of the preceding aspects, characterized in that the distal end of the diffuser (13), in particular the distal end of the cap (7), and / or the outermost surface of the diffuser (13) and / or the distal end of the protective means (52) and / or the distal end of the wave guide (12) is rounded, thickened, widened and / or conical shaped.

[0353] 21. Device as claimed in one or more of the preceding aspects, characterized in that the outer surface (19) of said cladding (2) is fused continuously and / or circumferentially and / or fully in the region (A) between said imperfections (18) to the inner surface (21), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused continuously and / or circumferentially and / or fully to the inner surface (21 ), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) is fused partially, preferably in a point-like manner and / or with longitudinal welds, in the region (A) between said imperfections (18) to the inner surface (21 ), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused partially, preferably in a point-like manner and / or with longitudinal welds, to the inner surface (21), preferably the inner diameter, of the cap (7).

[0354] 22. Device as claimed in one or more of the preceding aspects, characterized in that in the fused regions (32), in which the cladding (2) is fused to the cap (7), the cladding (2) and the cap (7) are firmly bonded, in particular in a material-locking manner.

[0355] 23. Device as claimed in one or more of the preceding aspects, characterized in that the core (1 ) has an outer diameter (22) between 100 and 1000 pm, preferably between 200 and 800 pm, more preferably between 300 and 700 pm and in particular between 350 and 600 pm, and / or in that the cladding (2) has an outer diameter (23) between 110 and 1200 pm, preferably between 210 and 960 pm, more preferably between 360 and 840 pm and in particular between 400 and 720 pm, and / or in that the material thickness (24) of the cladding (2) is between 1 % to 40 %, preferably between 5 % to 20 %, of the outer diameter (22) of the core (1 ).

[0356] 24. Device as claimed in one or more of the preceding aspects, characterized in that a protective sheath (25) is provided, preferably at the distal end of the wave guide (12), in particular wherein the protective sheath (25) comprises at least one buffer layer (3) adjacent to the cladding (2) of the core (1), and / or an outer sheath (14) and / or in particular wherein the protective sheath (25) and / or the outer sheath (14) is joined to the protection means (52) and / or the cap (7) and / or in particular wherein the protective sheath (25) and / or the outer sheath (14) is designed as a, preferably extruded, plastic coating.

[0357] 25. Device as claimed in one or more of the preceding aspects, characterized in that the protective sheath (25) and / or its outer sheath (14) is at least partially removed at the distal end of the wave guide (12) to bare the core (1 ) and its cladding (2) and / or in that the imperfections (18) extend into the cladding (2), preferably to bare the core (1 ), and / or into the core (1), in particular wherein the protective sheath (25) and / or its outer sheath (14) is provided additionally to the protection means (52) or is / are designed as the protection means (52) or a part of the protection means (52).

[0358] 26. Device as claimed in one or more of the preceding claims, characterized in that the imperfections (18) are designed as grooves (4, 5) adapted to refract and / or reflect the light propagating within the core (1 ) and its cladding (2) in generally radial directions, in particular wherein said grooves (4, 5) comprise at least two spiral grooves (4, 5), said grooves (4, 5) extending through said cladding (2) into said core (1 ), wherein successive grooves (4, 5) of the respective spiral grooves are alternating along the longitudinally extending outer surface (19) of the core (1) and its cladding (2), and / or in particular wherein said grooves comprise at least one circular and / or elliptical groove (26) and / or in particular wherein said grooves comprise at least one longitudinal groove (27) and / or in particular wherein said grooves comprise at least one point-like and / or broken groove (28).

[0359] 27. Device as claimed in one or more of the preceding aspects, characterized in that the depth (30) and / or the width (31 ) and / or the length of the imperfections (18), preferably of the grooves (4, 5), or groups and / or arrays of aligned perturbation centers (53) increases in a direction to the distal end of the core (1 ), in particular wherein the depth (30) and / or the width (31 ) and / or the length of the imperfections (18) increases up to 1000 %, preferably up to 800 %, more preferably up to 400 %, in particular in relation to the smallest depth (30) and / or width (31 ) and / or length of the imperfections (18).

[0360] 28. Device as claimed in one or more of the preceding aspects, characterized in that the core (1 ) and / or the cladding (2) comprises or consists of a material selected from the group of fused silica, in particular quartz glass, chalcogenide glass, arsenic sulfide glass, silver chloride glass, silver bromide glass and mixtures thereof, in particular wherein the material, preferably the exact material composition, of the core (1 ) differs from the material of the cladding (2), preferably to achieve a lower refractive index in the cladding (2) than in the core (1 ), and / or in particular wherein the material of the cladding (2) and / or the core (1 ) is doped, in particular wherein the cladding (2) is doped with fluorine and / or in particular wherein the core (1) is doped with germanium and / or in particular wherein the chalcogenide glass of the cladding (2) and / or the core (core) is doped, wherein, preferably, at least one of the fiber core (1) and the cladding (2) is doped with germanium, selenium, silver, indium or tellurium or rare earth elements.

[0361] 29. Device as claimed in one or more of the preceding aspects, characterized in that the region (A) provided with the imperfections (18), preferably recess(es) or perturbation center(s) (53), has a length (29) between 0.1 to 100 mm, preferably between 1 to 50 mm, more preferably between 3 to 4 mm.

[0362] 30. Device as claimed in one or more of the preceding aspects, characterized in that the distal end of the core (1 ) is terminated by a reflector (6), wherein, preferably, the reflector (6) is adapted to reflect the laser light energy and / or the electromagnetic radiation, in particular wherein the reflector (6) is formed by the distal end of the core (1 ) and / or the cladding (2) and / or in particular wherein the reflector (6), in particular designed as a cone, is shaped and / or curved inwards, facing to the distal end of the diffuser (13), or outwards, facing away from the distal end of the diffuser (13) and / or has a concave or convex design. 31. Device as claimed in one or more of the preceding aspects, characterized in that the reflector (6) has a conical shape, the cone angle of the reflector (6) designed as a reflecting cone selected from the range of 55 to 90 degrees, preferably 60 to 82 degrees, more preferably 60 + / - 4, 68 + / - 4 and / or 74 + / - 4 degrees.

[0363] 32. Device as claimed in one or more of the preceding aspects, characterized in that the proximal end of the bore of the cap (7) is provided with a section (8) having an increased inner diameter corresponding to the outer diameter of the buffer layer (3) and / or the diameter of the outer sheath (14) and / or the diameter of the protective sheath (25) and / or the outer diameter (22) of the core (1) and / or the outer diameter (23) of the cladding (2).

[0364] 33. Device as claimed in one or more of the preceding aspects, characterized in that the section (8) having the increased inner diameter at the proximal end of the cap (7) is glued to the at least one buffer layer (3) and / or to the protective sheath (25) and / or to the outer sheath (14) and / or to the core (1 ) and / or to the cladding (2), in particular wherein the glue (9) additionally provides a smooth transition between the outer surface, in particular the outer diameter of the cap (7) and that of the outer sheath (14).

[0365] 34. Device as claimed in one or more of the preceding aspects, characterized in that the inner surface (21) of the bore of the cap (7) is provided with an anti-reflective coating.

[0366] 35. Device as claimed in one or more of the preceding aspects, characterized in that the imperfections (18), preferably recess(es) or perturbation center(s) (53), are produced by material processing by means of a CO2 laser beam (20) or a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm by rotating the core (1 ) and its cladding (2) around its longitudinal axis (16) relative to the laser beam (20) and axially moving the laser beam (20) and / or the core (1 ) and its cladding (2) along the longitudinal axis (16) of the core (1 ) in a synchronized manner with the rotation of the core (1 ).

[0367] 36. Device as claimed in one or more of the preceding aspects, characterized in that the starting points of said spiral grooves (4, 5) are angularly offset in the circumferential direction of the core (1 ) by 360 degrees divided by the number of grooves. 37. Device as claimed in one or more of the preceding aspects, characterized in that the two or more spiral grooves (4, 5) have substantially the same pitch angle (a) value relative to the longitudinal axis (16) of the core (1) and extend in the same direction.

[0368] 38. Device as claimed in one or more of the preceding aspects, characterized in that the two or more spiral grooves (4, 5) have substantially the same pitch angle (a) value, but extend in opposite directions, such that successive grooves of respective pairs of the spiral grooves (4, 5) cross each other.

[0369] 39. Device as claimed in one or more of the preceding aspects, characterized in that the pitch angle (a) value of the spiral grooves (4, 5) relative to the longitudinal axis (16) of the core (1 ) is selected to be about 60°.

[0370] 40. Method for the production of a device (17) for treatment of body tissue according to one of the preceding aspects, wherein a sliding layer (51 ) is applied, in particular coated or embedded and / or in particular by brushing, dipping, immersing and / or extruding, on and / or in an outer surface of the diffuser (13), preferably on and / or in the protection means (52) and / or the cap (7), at least in certain regions, preferably in the region of the distal end of the diffuser (13), preferably the protection means (52) and / or the cap (7), in particular completely, in particular to reduce friction with and / or in particular to reduce adhesion to said surrounding tissue.

[0371] 41. Method according to aspect 40, characterized in that, preferably before applying the sliding layer (51 ), the outer surface (19) of the cladding (2) is fused in the region (A) between the imperfections (18) to the inner diameter of the cap (7) and / or in that, preferably before applying the sliding layer (51 ), the outer surface (19) of the cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused to the inner surface (21 ), preferably the inner diameter, of the cap (7).

[0372] 42. Method according to aspect 40 or 41 , characterized in that the device (17), preferably the light diffuser (13), more preferably the cap (7) and the cladding (2), is heated at least in the regions (A, B, C) to be fused, in particular so that the cap (7) at least partially collapses and is fused to the cladding (2) and / or the core (1 ), in particular wherein a vacuum is applied to the still open end of the cap (7) before and / or during the heating.

[0373] 43. Method according to one or more of aspects 40 to 42, characterized in that, preferably before applying the sliding layer (51 ) and / or in particular before fusing the outer surface (19) of the cladding (2) to the inner diameter of the cap (7), a part of the protective sheath (25) from the distal end of the wave guide (12) is removed, preferably the part covering the length of the section of the core (1 ) and its cladding (2) to be provided with the imperfections (18), in particular the grooves (4, 5) or perturbation centers (53), and / or in that, preferably before applying the sliding layer (51 ) and / or in particular before fusing the outer surface (19) of the cladding (2) to the inner diameter of the cap (7), a part of the outer sheath (14) of the protective sheath (25) is removed.

[0374] 44. Method according to one or more of aspects 40 to 43, characterized in that the reflector (6) at the distal end of the bared core (1) and its cladding (2) is provided, in particular by removing the material of the core (1 ) and / or the cladding (2).

[0375] 45. Method according to one or more of aspects 40 to 44, characterized in that the imperfections (18), preferably the grooves (4, 5) or the perturbation center(s) (53), are produced by material processing by means of a CO2 laser beam (20) or a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm, in particular wherein wave guide (12) and / or the core (1) and its cladding (2) are rotated around its longitudinal axis (16) relative to the laser beam (20) and / or in particular wherein the laser beam (20) and / or the wave guide (12) and the core (1 ) and the cladding (2) thereof are axially moved along the longitudinal axis (16) of the core (1 ) in a synchronized manner with the rotation of the core (1 ).

[0376] 46. Method according to one or more of aspects 40 to 45, characterized in that the protection means (52) is slid over the distal end of the wave guide (12), preferably is also slid onto a short length of the buffer layer (3) from which the outer sheath (14), in particular outer layer of the protective sheath (25), was removed and / or in that the cap (7) is slid over the region (A) provided with the imperfections (18) of the core (1 ) and cladding (2), preferably is also slid onto a short length of the buffer layer (3) from which the outer sheath (14), in particular outer layer of the protective sheath (25), was removed.

[0377] 47. Method according to one or more of aspects 40 to 46, characterized in that after the cap (7) is fused to the core (1 ) and / or the cladding (2), the proximal end of the cap (7) is glued to the protective sheath (15), preferably the buffer layer (3) and / or the outer sheath (14), in particular by inserting the diffuser (13) and / or the device (17) comprising the cap (7) with the distal end of the wave guide (12) contained therein through an annular seal at the top of a vacuum tight container having a glue filled flask at the bottom thereof and applying at least a partial vacuum within the container and / or by introducing the diffuser (13) and / or the device (17) up to beyond the distal end of the cap (7) into the glue filled flask, in particular wherein the vacuum is released from the container so that the glue (9) from the flask is sucked into, preferably any, gap(s) (15) between the cap (7), the buffer layer (3) and the unfused proximal end of the core (1 ) and its cladding (2) and / or in particular wherein the glue (9) is shaped and, preferably, bridges the proximal end of the cap (7) and the outer sheath (14), in particular outer layer, of the protective sheath (25) and, more preferably, any glue still adhering to the outer surface of the cap (7) is removed.

[0378] List of Reference Signs:

[0379] 1 Core

[0380] 2 Cladding

[0381] 3 Buffer layer

[0382] 4 Groove

[0383] 5 Groove

[0384] 6 Reflector

[0385] 7 Cap

[0386] 8 Section

[0387] 9 Glue

[0388] 10 Source

[0389] 11 Small gaps

[0390] 12 Wave guide

[0391] 13 Diffuser

[0392] 14 Outer sheath

[0393] 15 Small gaps

[0394] 16 Longitudinal axis of 1

[0395] 17 Device

[0396] 18 Imperfection

[0397] 19 Outer surface of 2

[0398] 20 Laser beam

[0399] 21 Inner surface of 7

[0400] 22 Outer diameter of 1

[0401] 23 Outer diameter of 2

[0402] 24 Sheath thickness of 2

[0403] 25 Protective sheath

[0404] 26 Elliptical groove

[0405] 27 Longitudinal groove

[0406] 28 Broken groove

[0407] 29 Length of A

[0408] 30 Depth of 18

[0409] 31 Width of 18

[0410] 32 Fused region

[0411] 40 Groove

[0412] 50 Groove

[0413] 51 Sliding layer 52 Protection means

[0414] 53 Perturbation center

[0415] 54 Lens set

[0416] 55 Laser beam

[0417] A Region

[0418] B Region

[0419] C Region

[0420] D Axis of 12 a Pitch angle

Claims

Claims:1 . Device (17) for treatment of body tissue, in particular for the permanent occlusion of varicose veins, preferably in the lower limbs, of varicocele and / or of vascular malformations and / or for the use in aesthetic surgeries, preferably laser assisted lipolysis, and / or for tumor treatment by means of laser induced thermotherapy and / or photodynamic therapy, and / or in particular for the irradiation of brain tissue, for ear-nose-throat applications, in particular necrosis of tissue, for surface disinfection by laser light, for dermatologic treatment, including application on skin and / or nails and / or for treatment of pilonidal sinus, anal fistula and / or hemorrhoids, by means of a light diffuser (13) for irradiating said tissue by laser light energy and / or by electromagnetic radiation, wherein the light diffuser (13) is designed to irradiate the radiation laterally with respect to a longitudinal center axis of the light diffuser (13) and endoluminally, characterized in that a sliding layer (51 ) is provided on an outer surface, in particular the outermost surface, of a distal end of the diffuser (13) at least in certain regions, preferably in the region of the front distal end of the diffuser (13) and / or in the region of the energy emission of the diffuser (13), in particular completely, in particular to reduce friction with and / or in particular to reduce adhesion to said surrounding tissue.

2. Device of claim 1 , characterized in that the sliding layer (51 ) is formed as a coating of the diffuser (13) or as a sliding agent, in particular on the exterior and / or outer surface of the diffuser (13).

3. Device of claim 1 or 2, characterized in that the sliding layer (51 ) comprises and / or consists of a plastic material and / or in that the sliding layer (51 ) comprises or consists of at least one material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroethylene, polysiloxane, higher order polysiloxane and mixtures thereof, and / or in that the material of the sliding layer (51) comprises silicone or consists of silicone.

4. Device as claimed in one or more of the preceding claims, characterized in that said diffuser (13) is connected and / or connectable at its proximal end to a source(10) of laser light energy and / or electromagnetic radiation via a flexible wave guide (12), wherein, preferably, the source (10) is part of the device (17), in particular wherein the wave guide (12) has at least one radiation emitting surface which is designed to emit the radiation laterally with respect to a longitudinal center axis of the light diffuser (13) and endoluminally and / or in particular wherein the laser light energy and / or the electromagnetic radiation provided by the source (10) has a wavelength of (1450 + / - 30) nm, (1950 + / - 40 nm) and / or a wavelength between 2700 nm to 3100 nm, preferably a wavelength of (2770 + / - 40 nm) and / or (2900 + / - 40) nm, and / or a wavelength of (6100 + / - 40) nm.

5. Device as claimed in one or more of the preceding claims, characterized in that the distal end of the diffuser (13) comprises a protection means (52) which encloses at least a protection part of the wave guide (12), preferably a part of an energy emitting segment and / or a part of a segment comprising the radiation emitting surface or surfaces, more preferably the whole length of the energy emitting segment and / or the whole length of the segment comprising the radiation emitting surface or surfaces.

6. Device as claimed in one or more of the preceding claims, characterized in that the energy emitting segment and / or the segment comprising the radiation emitting surface or surfaces has a length up to 10 cm, preferably a length between 0,1 to 100 cm, more preferably between 1 to 50 mm, in particular between 3 to 4 mm.

7. Device as claimed in one or more of the preceding claims, characterized in that the protection means (52) is part of the wave guide (12) or is connected to the wave guide (12) preferably in a fluid tight and / or liquid tight manner, in particular wherein the protection means (52) comprises the outer surface, in particular the outermost surface, of the diffuser (13) and / or in particular wherein the protection means (52) encloses the protection part in a fluid tight and / or liquid-tight manner.

8. Device as claimed in one or more of the preceding claims, characterized in that the protection means (52) is designed as a coated layer of the wave guide (12), a protective sheath (25) and / or an outer sheath (14) of the protective sheath (25) of the wave guide (12) and / or the protection means (52) is designed as a cap (7), enclosing the distal end of the wave guide (12),in particular wherein the cap (7) is a fused silica cap and / or in particular wherein the cap (7) comprises and / or consists of a plastic material and / or in particular wherein the cap (7) comprises or consists of a material selected from the group of polytetrafluoroethylene, polyethene-co-tetrafluoroethylene, polysiloxane, higher order polysiloxane and mixtures thereof, and / or in particular wherein the material of the cap (7) comprises silicone or consists of silicone.

9. Device as claimed in one or more of the preceding claims, characterized in that the protection means (52) is transparent or translucent to the radiation energy in particular emitted by the diffuser (13).

10. Device as claimed in one or more of the preceding claims, characterized in that the sliding layer (51 ) is provided at least partially, preferably completely, on the outer surface of the protection means (52), in particular wherein the sliding layer (51 ) is provided at least in certain regions, preferably in the region in the outermost distal end of the protection means (52), preferably completely, on the protection means (52), and / or in that the protection means (52) is designed as the sliding layer (51 ).

11. Device as claimed in one or more of the preceding claims, characterized in that the wave guide (12) comprises at least one fiber optic core (1 ) covered by at least one cladding (2) having a refractive index smaller than that of the core (1 ), in particular wherein the wave guide (12) is an optical fiber.

12. Device as claimed in one or more of the preceding claims, characterized in that the sliding layer (51 ) is transparent or translucent for the emitted laser energy.

13. Device as claimed in one or more of the preceding claims, characterized in that the sliding layer (51 ) has a material thickness of at most 0.5 mm, preferably at most 0.1 mm, more preferably at most 0.05 mm, in particular between 0.01 mm to 0.1 mm.

14. Device as claimed in one or more of the preceding claims, characterized in that a cap (7) which is transparent or translucent to the radiation energy enclosing the distal end of the core (1 ) and its cladding (2) in a fluid tight and / or liquid tight manner is provided.

15. Device as claimed in one or more of the preceding claims, characterized in that the light diffuser (13) irradiates circumferentially said tissue by laser light energy and / or electromagnetic radiation.

16. Device as claimed in one or more of the preceding claims, characterized in that in the cladding (2) and / or in the core (1) and / or in a boundary between the core (1 ) and the cladding (2) imperfections (18) are provided, designed either as one or several recess(es) or as one or several perturbation center(s) (53) and adapted to direct the electromagnetic radiation, preferably to refract and / or reflect the laser light energy propagating within the core (1) and / or its cladding (2) in generally lateral, preferably radial, directions, in particular the perturbation centers (53) are implemented as local variations in the refractive index of the material of the core (1 ) and / or cladding (2), scattering centers, voids, and / or bubbles, in particular designed as micro-cracks or material impurities.

17. Device as claimed in one or more of the preceding claims, characterized in that the imperfections (18) are designed as perturbation centers (53) which are aligned in groups or patterns along the longitudinal extension of the wave guide (12), in particular wherein the perturbation centers (53) take form of one or several geometries, in particular as circle, spiral, line and / or cuboid, and / or in particular wherein each geometry of the perturbation centers (53) can be oriented along or orthogonally with respect to the longitudinal extension of the wave guide (12) and / or in particular wherein the geometries of the perturbation centers (53) are different or repeat within the area provided with the imperfections (18).

18. Device as claimed in one or more of the preceding claims, characterized in that the perturbation centers (53) are only provided and / or located in the fiber core (1), preferably only in the innermost cross-section of the fiber core (1 ) defined by the radius range from 0 to 80 % of the fiber core (1 ), more preferably defined by the radius range from 0 to 60 % of the fiber core (1 ), in particular defined as the radius range from 0 to 40% of the fiber core (1 ), in particular each starting from the center of the fiber core (1 ).

19. Device as claimed in one or more of the preceding claims, characterized in that the outer surface (19) of said cladding (2) is fused in or next to the region (A) of saidimperfections (18) at least in parts to the inner surface (21), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused at least in parts to the inner surface (21 ), preferably the inner diameter, of the cap (7).

20. Device as claimed in one or more of the preceding claims, characterized in that the distal end of the diffuser (13), in particular the distal end of the cap (7), and / or the distal end of the protective means (52) and / or the distal end of the wave guide (12) and / or the outermost surface of the diffuser (13) is rounded, thickened, widened and / or conical shaped.

21. Device as claimed in one or more of the preceding claims, characterized in that the outer surface (19) of said cladding (2) is fused continuously and / or circumferentially and / or fully in the region (A) between said imperfections (18) to the inner surface (21), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused continuously and / or circumferentially and / or fully to the inner surface (21 ), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) is fused partially, preferably in a point-like manner and / or with longitudinal welds, in the region (A) between said imperfections (18) to the inner surface (21 ), preferably the inner diameter, of the cap (7) and / or in that the outer surface (19) of said cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused partially, preferably in a point-like manner and / or with longitudinal welds, to the inner surface (21), preferably the inner diameter, of the cap (7).

22. Device as claimed in one or more of the preceding claims, characterized in that in the fused regions (32), in which the cladding (2) is fused to the cap (7), the cladding (2) and the cap (7) are firmly bonded, in particular in a material-locking manner.

23. Device as claimed in one or more of the preceding claims, characterized in that the core (1) has an outer diameter (22) between 100 and 1000 pm, preferablybetween 200 and 800 m, more preferably between 300 and 700 pm and in particular between 350 and 600 pm, and / or in that the cladding (2) has an outer diameter (23) between 110 and 1200 pm, preferably between 210and 960 pm, more preferably between 360 and 840 pm and in particular between 400 and 720 pm, and / or in that the material thickness (24) of the cladding (2) is between 1 % to 40 %, preferably between 5 % to 20 %, of the outer diameter (22) of the core (1 ).

24. Device as claimed in one or more of the preceding claims, characterized in that a protective sheath (25) is provided, preferably at the distal end of the wave guide (12), in particular wherein the protective sheath (25) comprises at least one buffer layer (3) adjacent to the cladding (2) of the core (1), and / or an outer sheath (14) and / or in particular wherein the protective sheath (25) and / or the outer sheath (14) is joined to the protection means (52) and / or the cap (7) and / or in particular wherein the protective sheath (25) and / or the outer sheath (14) is designed as a, preferably extruded, plastic coating.

25. Device as claimed in one or more of the preceding claims, characterized in that the protective sheath (25) and / or its outer sheath (14) is at least partially removed at the distal end of the wave guide (12) to bare the core (1 ) and its cladding (2) and / or in that the imperfections (18) extend into the cladding (2), preferably to bare the core (1 ), and / or into the core (1), in particular wherein the protective sheath (25) and / or its outer sheath (14) is provided additionally to the protection means (52) or is / are designed as the protection means (52) or a part of the protection means (52).

26. Device as claimed in one or more of the preceding claims, characterized in that the imperfections (18) are designed as grooves (4, 5) adapted to refract and / or reflect the light propagating within the core (1 ) and its cladding (2) in generally radial directions, in particular wherein said grooves (4, 5) comprise at least two spiral grooves (4, 5), said grooves (4, 5) extending through said cladding (2) into said core (1 ), whereinsuccessive grooves (4, 5) of the respective spiral grooves are alternating along the longitudinally extending outer surface (19) of the core (1) and its cladding (2), and / or in particular wherein said grooves comprise at least one circular and / or elliptical groove (26) and / or in particular wherein said grooves comprise at least one longitudinal groove (27) and / or in particular wherein said grooves comprise at least one point-like and / or broken groove (28).

27. Device as claimed in one or more of the preceding claims, characterized in that the depth (30) and / or the width (31 ) and / or the length of the imperfections (18), preferably of the grooves (4, 5), or groups and / or arrays of aligned perturbation centers (53) increases in a direction to the distal end of the core (1 ), in particular wherein the depth (30) and / or the width (31 ) and / or the length of the imperfections (18) increases up to 1000 %, preferably up to 800 %, more preferably up to 400 %, in particular in relation to the smallest depth (30) and / or width (31 ) and / or length of the imperfections (18).

28. Device as claimed in one or more of the preceding claims, characterized in that the core (1 ) and / or the cladding (2) comprises or consists of a material selected from the group of fused silica, in particular quartz glass, chalcogenide glass, arsenic sulfide glass, silver chloride glass, silver bromide glass and mixtures thereof, in particular wherein the material, preferably the exact material composition, of the core (1 ) differs from the material of the cladding (2), preferably to achieve a lower refractive index in the cladding (2) than in the core (1 ), and / or in particular wherein the material of the cladding (2) and / or the core (1 ) is doped, in particular wherein the cladding (2) is doped with fluorine and / or in particular wherein the core (1) is doped with germanium and / or in particular wherein the chalcogenide glass of the cladding (2) and / or the core (core) is doped, wherein, preferably, at least one of the fiber core (1) and the cladding (2) is doped with germanium, selenium, silver, indium or tellurium or rare earth elements.

29. Device as claimed in one or more of the preceding claims, characterized in that the region (A) provided with the imperfections (18), preferably recess(es) or perturbation center(s) (53), has a length (29) between 0.1 to 100 mm, preferably between 1 to 50 mm, more preferably between 3 to 4 mm.

30. Device as claimed in one or more of the preceding claims, characterized in that the distal end of the core (1 ) is terminated by a reflector (6), wherein, preferably, the reflector (6) is adapted to reflect the laser light energy and / or the electromagnetic radiation, in particular wherein the reflector (6) is formed by the distal end of the core (1 ) and / or the cladding (2) and / or in particular wherein the reflector (6), in particular designed as a cone, is shaped and / or curved inwards, facing to the distal end of the diffuser (13), or outwards, facing away from the distal end of the diffuser (13) and / or has a concave or convex design.

31. Device as claimed in one or more of the preceding claims, characterized in that the reflector (6) has a conical shape, the cone angle of the reflector (6) designed as a reflecting cone selected from the range of 55 to 90 degrees, preferably 60 to 82 degrees, more preferably 60 + / - 4, 68 + / - 4 and / or 74 + / - 4 degrees.

32. Device as claimed in one or more of the preceding claims, characterized in that the proximal end of the bore of the cap (7) is provided with a section (8) having an increased inner diameter corresponding to the outer diameter of the buffer layer (3) and / or the diameter of the outer sheath (14) and / or the diameter of the protective sheath (25) and / or the outer diameter (22) of the core (1 ) and / or the outer diameter (23) of the cladding (2).

33. Device as claimed in one or more of the preceding claims, characterized in that the section (8) having the increased inner diameter at the proximal end of the cap (7) is glued to the at least one buffer layer (3) and / or to the protective sheath (25) and / or to the outer sheath (14) and / or to the core (1 ) and / or to the cladding (2), in particular wherein the glue (9) additionally provides a smooth transition between the outer surface, in particular the outer diameter of the cap (7) and that of the outer sheath (14).

34. Device as claimed in one or more of the preceding claims, characterized in that the inner surface (21) of the bore of the cap (7) is provided with an anti-reflective coating.

35. Device as claimed in one or more of the preceding claims, characterized in that the imperfections (18), preferably recess(es) or perturbation center(s) (53), are produced by material processing by means of a CO2 laser beam (20) or a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm by rotating the core (1 ) and its cladding (2) around its longitudinal axis (16) relative to the laser beam (20) and axially moving the laser beam (20) and / or the core (1 ) and its cladding (2) along the longitudinal axis (16) of the core (1 ) in a synchronized manner with the rotation of the core (1 ).

36. Device as claimed in one or more of the preceding claims, characterized in that the starting points of said spiral grooves (4, 5) are angularly offset in the circumferential direction of the core (1 ) by 360 degrees divided by the number of grooves.

37. Device as claimed in one or more of the preceding claims, characterized in that the two or more spiral grooves (4, 5) have substantially the same pitch angle (a) value relative to the longitudinal axis (16) of the core (1) and extend in the same direction.

38. Device as claimed in one or more of the preceding claims, characterized in that the two or more spiral grooves (4, 5) have substantially the same pitch angle (a) value, but extend in opposite directions, such that successive grooves of respective pairs of the spiral grooves (4, 5) cross each other.

39. Device as claimed in one or more of the preceding claims, characterized in that the pitch angle (a) value of the spiral grooves (4, 5) relative to the longitudinal axis (16) of the core (1 ) is selected to be about 60°.

40. Method for the production of a device (17) for treatment of body tissue according to one of the preceding claims, wherein a sliding layer (51 ) is applied, in particular coated or embedded and / or in particular by brushing, dipping, immersing and / or extruding, on and / or in an outer surface of the diffuser (13), preferably on and / or in the protection means (52) and / or the cap (7), at least in certain regions, preferably in the region of the distal end of thediffuser (13), preferably the protection means (52) and / or the cap (7), in particular completely, in particular to reduce friction with and / or in particular to reduce adhesion to said surrounding tissue.

41. Method according to claim 40, characterized in that, preferably before applying the sliding layer (51 ), the outer surface (19) of the cladding (2) is fused in the region (A) between the imperfections (18) to the inner diameter of the cap (7) and / or in that, preferably before applying the sliding layer (51 ), the outer surface (19) of the cladding (2) extending over a distance in front and / or behind the region (A) provided with the imperfections (18) is fused to the inner surface (21 ), preferably the inner diameter, of the cap (7).

42. Method according to claim 40 or 41 , characterized in that the device (17), preferably the light diffuser (13), more preferably the cap (7) and the cladding (2), is heated at least in the regions (A, B, C) to be fused, in particular so that the cap (7) at least partially collapses and is fused to the cladding (2) and / or the core (1 ), in particular wherein a vacuum is applied to the still open end of the cap (7) before and / or during the heating.

43. Method according to one or more of claims 40 to 42, characterized in that, preferably before applying the sliding layer (51 ) and / or in particular before fusing the outer surface (19) of the cladding (2) to the inner diameter of the cap (7), a part of the protective sheath (25) from the distal end of the wave guide (12) is removed, preferably the part covering the length of the section of the core (1 ) and its cladding (2) to be provided with the imperfections (18), in particular the grooves (4, 5) or perturbation centers (53), and / or in that, preferably before applying the sliding layer (51 ) and / or in particular before fusing the outer surface (19) of the cladding (2) to the inner diameter of the cap (7), a part of the outer sheath (14) of the protective sheath (25) is removed.

44. Method according to one or more of claims 40 to 43, characterized in that the reflector (6) at the distal end of the bared core (1) and its cladding (2) is provided, in particular by removing the material of the core (1 ) and / or the cladding (2).

45. Method according to one or more of claims 40 to 44, characterized in that the imperfections (18), preferably the grooves (4, 5) or the perturbation center(s) (53),are produced by material processing by means of a CO2 laser beam (20) or a Femtosecond pulse laser beam of preferably between 500 nm to 530 nm and / or preferably between 1030 nm to 1090 nm, in particular wherein wave guide (12) and / or the core (1) and its cladding (2) are rotated around its longitudinal axis (16) relative to the laser beam (20) and / or in particular wherein the laser beam (20) and / or the wave guide (12) and the core (1 ) and the cladding (2) thereof are axially moved along the longitudinal axis (16) of the core (1 ) in a synchronized manner with the rotation of the core (1 ).

46. Method according to one or more of claims 40 to 45, characterized in that the protection means (52) is slid over the distal end of the wave guide (12), preferably is also slid onto a short length of the buffer layer (3) from which the outer sheath (14), in particular outer layer of the protective sheath (25), was removed and / or in that the cap (7) is slid over the region (A) provided with the imperfections (18) of the core (1 ) and cladding (2), preferably is also slid onto a short length of the buffer layer (3) from which the outer sheath (14), in particular outer layer of the protective sheath (25), was removed.

47. Method according to one or more of claims 40 to 46, characterized in that after the cap (7) is fused to the core (1 ) and / or the cladding (2), the proximal end of the cap (7) is glued to the protective sheath (15), preferably the buffer layer (3) and / or the outer sheath (14), in particular by inserting the diffuser (13) and / or the device (17) comprising the cap (7) with the distal end of the wave guide (12) contained therein through an annular seal at the top of a vacuum tight container having a glue filled flask at the bottom thereof and applying at least a partial vacuum within the container and / or by introducing the diffuser (13) and / or the device (17) up to beyond the distal end of the cap (7) into the glue filled flask, in particular wherein the vacuum is released from the container so that the glue (9) from the flask is sucked into, preferably any, gap(s) (15) between the cap (7), the buffer layer (3) and the unfused proximal end of the core (1 ) and its cladding (2) and / or in particular wherein the glue (9) is shaped and, preferably, bridges the proximal end of the cap (7) and the outer sheath (14), in particular outer layer, of the protective sheath (25) and, more preferably, any glue still adhering to the outer surface of the cap (7) is removed.

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