DE102016111363B4 - Endoscope with flexibly bonded light guide - Google Patents

Abstract

Medical endoscope with an elongate shaft part that is flexible at least in sections, through which at least one light guide having a large number of individual fibers runs in the longitudinal direction, characterized in that fibers of the light guide in a region in which they pass through a flexible section of the shaft part, by means of a flexible adhesive are bonded, fibers of the light guide being additionally bonded to the distal end of the shaft part and/or to the proximal end of the shaft part by means of an inflexible adhesive.

Description

The invention relates to a medical endoscope of the type mentioned in the preamble of claim 1 and a method for assembling it. In particular, the invention relates to medical endoscopes with a semi-flexible shaft part.

Endoscopes with a semi-flexible, i.e. only partially flexible, shaft part are used, for example, in urology and are referred to there as urethroscopes. Urethoscopes are surgical instruments used in urology for endoscopic work in the ureter and renal pelvis. In order to reach this area endoscopically, i.e. without bleeding, the urethroscope is pushed from the outside through the urethra (urethra) into the bladder, from there through the ostium (mouth of the ureter with sealing valve) into the ureter (ureter) and in this up to advanced to the operating area, eg up to a stone or a narrowing in the ureter or up to the renal pelvis.

Urethoscopes are designed in an endoscopic design with an elongated shaft and can, for example, allow the operating area to be observed with an optical system and the associated lighting. The shaft of the urethroscope should be at least 330 mm long. Since the ureter and especially the ostium are very narrow, the shaft diameter should not be larger than about 3 to 4 mm. This results in a very long and thin configuration of the steerer tube.

The shaft tube of a urethroscope should be stiff to allow directing of the distal end from the proximal end, especially during difficult insertion into the ostium. The shaft tube is therefore generally rigid and has an outer metal tube which gives it the necessary rigidity and which encloses the inner parts of the shaft part in a liquid-tight manner. However, a certain degree of elastic deformability of the shaft part is required in order to be able to access the examination area during an intervention.

At least one viewing device is usually provided inside the shaft tube, as well as light guides for illumination and preferably a working channel that enables the introduction of instruments, such as catheters, forceps, stone traps, lithotriptors (stone crushing devices), etc. In particular, the distal front is usually used for illumination At least one fiber optic bundle is provided in the shaft tube in the work area lying the urethroscope. When the shaft part elastically deforms, fiber optic bundles drawn in freely in the interior of an endoscope run the risk of being damaged by the other channels drawn into the shaft part, since they exert pressure or friction on the fiber optic bundle and can thus damage individual fibers.

A generic urethroscope is in DE 43 35 783 A1 shown. The light guide formed from optical fibers fills the space between the inner metal tubes and the outer metal tube.

WO 2016/041 637 A1 describes the fixation of optical fibers in an endoscope in that the distal end area of the fiber bundle is fixed in a sleeve and the sleeve is then used as a component and installed with the endoscope optics. For attachment and easier assembly, the fiber bundle can be glued in the sleeve. The fiber bundle is placed with the sleeve in another tube, which is arranged as an outer tube, which also forms the outer wall of the endoscope optics.

the JP 2008 - 212 309 A discloses an endoscope having light guides bonded with an adhesive in the region of the distal tip.

In the DE 195 21 298 A1 describes a catheter system in which optical fibers are attached to the outer wall of the catheter balloon by a layer of adhesive.

it's over DE 199 28 289 A1 known to seal an endoscope, such as a urethroscope, at the distal end of its shaft part with a window for the optics and with a sufficiently tight bonding of the fibers of the light guide bundle. However, the optical fiber bundle can be laid freely in the sealed housing of the endoscope.

A disadvantage of these known constructions is that the walls of the shaft area and the elements running through the shaft in semi-flexible endoscopes are subject to not inconsiderable stresses as soon as a flexible section of the shaft area is bent. Friction can occur between the elements laid in the shaft area and, in particular, the freely laid optical fibers can be damaged. Damage can occur, for example, if the optical fibers get between the elements laid in the socket area or between these and the socket inner wall when the socket bends.

In order to circumvent these problems, in the past, individual light guides were pulled into their own light guide tube, eg made of metal, which, together with the other channels in the endo scope shaft was misplaced. However, this solution involves a great deal of work and unnecessarily increases the volume occupied by the light guide in the small shaft diameter.

The object of the present invention is therefore to design an endoscope of the generic type in such a way that the light guides contained therein, which have a large number of individual fibers, are not damaged when a section of the shaft part is bent and that at the same time the volume occupied by the light guide in the interior of the shaft part is as small as possible is held.

Description of the invention

The object is achieved by an endoscope that has the characterizing features of claim 1 and by methods for its assembly that have the characterizing features of claim 9 or 10 . The dependent claims relate to advantageous developments of the invention.

According to the invention, fibers of the light guide are bonded by means of a flexible adhesive at least in a region of the light guide that runs through a flexible section of the shaft part, with fibers of the light guide additionally being bonded to the distal end of the shaft part and/or to the proximal end of the shaft part by means of an inflexible adhesive . This stabilizes the light guide and protects it from damage caused by friction or pressure. In particular, it is not necessary to protect the light guide by means of a sheathing with a separate light guide channel.

In a first aspect, the invention thus relates to a medical endoscope with an elongate, at least partially flexible shaft part through which at least one light guide having a large number of individual fibers runs in the longitudinal direction, characterized in that fibers of the light guide in a region in which they pass through a flexible section of the shaft part, are bonded by means of a flexible adhesive, fibers of the light guide being additionally bonded to the distal end of the shaft part and/or to the proximal end of the shaft part by means of an inflexible adhesive.

The medical endoscopes according to the invention have an elongated shaft part and an operating part (herein also: main body) adjoining it proximally. The shaft part is preferably formed by a sealed housing. This can be designed, for example, in the form of a handle tube. In other words, the shaft part thus preferably comprises an outer handle tube or outer tube. In addition, the shaft part can contain further inner tubes, as well as various elements drawn into the shaft part, such as working channels, fiber tubes, optical channels, further light guides and the like.

Those skilled in the art are aware of suitable materials, such as steel, from which the housing of the shank portion can be made. In particular, materials are suitable that ensure sufficient flexibility of the shaft part. The shaft part can thus bend during examinations in order to follow the passages of organs, in particular the urethra and the ureters.

It is particularly preferred that the medical endoscope is a urethroscope. Urethroscopes (also synonymous: ureteroscopes) are used for examinations of the ureters and kidneys and therefore have a particularly long shaft section that must be flexible enough. Alternatively, the medical endoscope can also be any other endoscope that has or can have a flexible or semi-flexible shaft part. In this context, “semi-flexible” means that the shaft part comprises at least one flexible and at least one less flexible or inflexible section.

The shaft part is flexible at least in sections. In other words, the shaft part is elastically deformable at least in sections. This enables the user to reach the examination site through the organ openings during the examination without damaging organs. The bending in the shaft part that occurs during handling will usually be (passively) reversible, i.e. with proper, normal use of the endoscope, so that the deformation disappears when the load is removed, e.g. when the endoscope is removed from the patient's body, see above that the shaft part returns to its original shape. A flexible section of the shaft part preferably has a round cross-section.

As described above, the person skilled in the art is aware of preferred materials for producing the shaft part. A preferred material for forming the outer tube is steel, for example. According to the invention, in particular the ratio of the shaft diameter to the length of the shaft is selected such that the shaft is flexible at least in sections. The diameter of the shaft part is very small. The shaft part can have a diameter of about 0.5 mm to 8 mm, preferably about 1 mm to 5 mm, particularly preferably 2 mm to 4 mm. The length of the shaft part, on the other hand, is long enough to ensure comfortable handling and the ability to reach the surgical site. So the shaft part can have a length of about 200 mm to 600 mm, preferably 300 mm to 500 mm, more preferably about 330 to 430 mm.

The shaft part does not have to be bendable or flexible over the entire length. However, it is preferred that the flexible portion of the shaft portion has a length of about 100mm to 500mm, more preferably 180mm to 380mm, most preferably 250mm to 350mm.

In addition to the flexible or pliable section, the shaft part preferably also includes a stiffened section that is less flexible than the flexible section. In this context, “stiffened” means that the section is preferably not elastically deformable or only elastically deformable to a significantly reduced extent compared to the flexible section. This stiffened section is preferably formed in the distal area of the shaft part. This configuration ensures that the user of the endoscope is able to accurately move the distal end of the endoscope to the desired area. A flexible section of the shaft part preferably adjoins the distal, stiffened section proximally.

Methods for stiffening the shaft part in a designated section are known to those skilled in the art. For example, the stiffened section of the shaft part can have a shape in cross section that deviates from the circular shape, i.e. have a non-round cross section. For example, the stiffened portion may be oval or triangular, with the latter alternative having rounded corners of the triangular shape.

The (e.g. distal) stiffened section of the shaft part can have a length of about 30 mm to 180 mm, preferably about 50 mm to 150 mm, more preferably about 80 mm to 120 mm. In a preferred embodiment, the shaft part has a first, stiffened section with a length of approximately 50 to 150 mm and a second, flexible section with a length of approximately 180 mm to 380 mm.

A light guide having a large number of individual fibers runs through the shaft part in the longitudinal direction. This means that the light guide comprising a multiplicity of individual fibers extends essentially over the entire length of the shaft part, i.e. from its proximal to its distal end. Because the light guide is protected by bonding with a flexible adhesive according to the present invention, the light guide will remain substantially intact even after regular use of the endoscope. This means, for example, that even after repeated use, more than 70%, preferably more than 80%, more preferably more than 90% of the fibers of the light guide are intact over the entire length of the shaft part. In this context, "intact" means that the light transmission through the fiber has not been affected by damage, such as tearing of the fiber.

The light guide is suitable for conducting light from a light source to the distal end of the shaft part. Suitable light guides having a large number of individual fibers are known to the person skilled in the art and are routinely used in endoscopy or urethroscopy. The at least one light guide is preferably designed as an optical fiber bundle, i.e. as a bundle of optical fibers. An optical fiber bundle has multiple optical fibers, e.g. multiple glass fibers. Optical fibers can be, for example, glass fibers or plastic-based fibers. The light guide or the fiber optic bundle can be coupled or connected to an external light source.

The light guide, i.e. the optical fiber bundle, preferably has a thickness of 0.4 to 0.8 mm, more preferably 0.5 to 0.71 mm.

The fibers of the light guide are bonded by means of a flexible adhesive in an area in which they pass through a flexible section of the shaft part. "Area" or "area-by-area" are used herein synonymously with "section" or "section-by-section". Bonding with a flexible adhesive ensures that when a flexible section of the shaft part bends, the light guide can adapt to the movement of the shaft part and at the same time is protected from pressure and friction from other components (e.g. channels) contained in the shaft part. At the same time, it is no longer necessary to protect the light guide from the other components by encasing it with another channel wall. Pulling in the glued light guide during assembly is also significantly easier, so that the use of, for example, a light guide sleeve in the end areas of the light guide is no longer necessary.

In a preferred embodiment, the light guide having a multiplicity of individual fibers is therefore not surrounded by a light guide channel and/or by a sleeve in its end regions. Instead, the light guide runs through the shaft part directly adjacent to, or only separated by a layer of adhesive, from other channels, such as the working channel and the optical channel (also known as the fiber channel).

According to the invention, any flexible adhesive can be used to bond the fibers of the light guide. After it has hardened, the flexible adhesive should have sufficient flexibility that allows the light guide to adapt to the expected elastic deformation of the shaft partly adapt. At the same time, after the flexible adhesive has cured, the bond is strong enough to hold the fibers of the light guide together, ie to fix them to one another. Suitable flexible adhesives include silicone adhesives.

In a particularly preferred embodiment, the flexible adhesive is a silicone adhesive. Suitable silicone adhesives are commercially available and known to those skilled in the art. A suitable silicone adhesive is e.g. Elastosil E41.

According to the invention, the fibers of the light guide are glued to one another by means of a flexible adhesive. This means that fibers of the light guide are glued together to form a flexible fiber bundle. In particular, the fibers are bonded in such a way that essentially all of the fibers of a light guide are held together in the bonded section of the light guide. For this, it is not necessary for each individual fiber to be glued to its neighboring fibers inside the light guide. However, as a rule, at least the fibers lying on the outside in the light guide will be glued to their neighbors.

In addition, the light guide can be surrounded by the flexible adhesive at least in regions in the relevant section. The adhesive layer applied around the light guide is preferably on average thinner than 0.1 mm, more preferably thinner than 0.05 mm, even more preferably thinner than 0.01 mm. Furthermore, the light guide can be connected to the inner wall of the shaft part by means of the flexible adhesive. In other words, the free space within the flexible section(s) of the shaft part can be filled at least in regions with the flexible adhesive. Free space is that space not occupied by the light guide itself or by the various other components described herein, such as working and optics channels. The free space is not the space within the last-mentioned or other channels drawn into the shaft part, but the remaining free space within the inner wall of the shaft part. In one embodiment, the free space within the flexible section(s) of the shaft part is essentially completely filled with the flexible adhesive.

The light guide can have a round cross-section, but can also adapt to and fill the free space in the shaft part. Since the light guide is flexibly glued, its cross-sectional shape can also vary.

The gluing takes place in an area in which the fibers pass through a flexible section of the shaft part. Preferably, the fibers are bonded together over the entire length of a flexible section, or at least over 80% of the length of a flexible region.

In principle, it is advantageous to glue the fibers of the light guide essentially in all areas that run through a flexible section of the shaft part. It is therefore preferred according to the invention that the fibers of the light guide are bonded over at least 90%, preferably at least 95% or, most preferably, over about 100% of the length of the regions of the light guide that pass through flexible sections of the shaft part.

The endoscopes according to the invention generally have a shaft part which consists of at least 60%, preferably at least 70%, more preferably at least 80% flexible sections. It is thus preferred that the light guide is glued over a length of at least 60%, preferably at least 70%, more preferably at least 80% of the shaft part.

Fibers of the light guide or light guides are additionally glued to the distal end of the shaft part and/or to the proximal end of the shaft part by means of an inflexible adhesive. For example, the shaft part can be sealed at the distal end by means of a sufficiently tight bond with an inflexible adhesive and, for example, a window for the optics. It is preferred here that the flexible adhesive and the inflexible adhesive are spaced apart from one another in the shaft part.

The endoscope may contain one, two, three or more light guides as described herein. In a preferred embodiment, the endoscope contains two light guides. In addition to the light guide(s), the endoscope can contain other components, such as a fiber channel, working channel and the like. The endoscope therefore typically includes, for example, endoscope optics, which are usually laid in a fiber duct.

In a further aspect, the invention relates to a method for assembling a medical endoscope according to the invention, characterized in that it comprises steps in which (a) a light guide having a large number of individual fibers is wetted in regions with the flexible adhesive, (b) curing the adhesive and (c) then pulls the light guide into the shaft part.

The wetting of areas of the fiber bundle in step (a) can take place, for example, by immersing the area in the adhesive or by applying the adhesive to the desired area of a bundle. The application / immersion can This can be done, for example, in the desired area of the light guide by pulling the area of the light guide together with the flexible adhesive through an opening that is only slightly larger than the cross section of the light guide. In particular, it is not necessary to wet each fiber of the light guide individually with the adhesive. Surprisingly, it was found that it is sufficient to connect the fiber bundle by external wetting with the adhesive in certain areas (ie in sections).

It goes without saying that the fiber bundle is preferably wetted in an area which will pass through a flexible section of the shaft part after step (c), i.e. in an area which is intended for drawing into a flexible section of the shaft part.

The adhesive is then cured in step (b). The adhesive can be cured, for example, by air drying the adhesive. Such gentle drying in the air ensures that the necessary flexibility of the adhesive is maintained.

After the flexible adhesive has hardened, the light guide can finally be drawn into the shaft part in step (c). Methods for this are known to the person skilled in the art. Feeding can be done manually or automatically.

In an alternative aspect, the invention relates to a method for assembling a medical endoscope according to the invention, characterized in that it comprises steps in which (a) a light guide having a large number of individual fibers is drawn into the shaft part, (b) the flexible adhesive is drawn into a Injecting portion of the stem portion and (c) allowing the adhesive to cure.

Methods for drawing a light guide having a multiplicity of individual fibers into the shaft part are known to the person skilled in the art, as described elsewhere. The unglued fiber bundle is preferably drawn in manually.

In this method, the light guide is first drawn into the shaft part and only then is it wetted in areas or sections with the adhesive by injecting the adhesive. The adhesive can be injected with a cannula, for example. In this way, the desired sections in the shaft part are reached precisely. It will be understood that the portion into which the adhesive is injected in step (b) is preferably or comprises a flexible portion of the shaft portion.

Curing of the adhesive in step (c) occurs as described elsewhere herein.

character list

• 1 eine Seitenansicht eines erfindungsgemäßen Urethroskops,
• 2 einen Schnitt nach Linie III-III in 1 durch einen flexiblen Abschnitt des Schaftteils,
• 3a einen Schnitt durch einen distalen, versteiften Abschnitt des Schaftteils, und
• 3b einen Schnitt durch einen distalen, versteiften Abschnitt eines alternativen Schaftteils.

In the drawings, exemplary embodiments of the invention are shown schematically. Show it:

• 1 a side view of a urethroscope according to the invention,
• 2 a cut along line III-III in 1 through a flexible section of the shaft part,
• 3a a section through a distal, stiffened section of the shaft part, and
• 3b a section through a distal, stiffened portion of an alternative shaft part.

exemplary embodiments

Further advantages, characteristics and features of the present invention become clear in the following detailed description of exemplary embodiments with reference to the accompanying drawings. However, the invention is not limited to these exemplary embodiments.

1 shows a side view of a urethroscope 2 according to the invention with a main body 6 and a distally adjoining elongated tubular shaft part 8 to be inserted into the patient's body. The main body 6 can include an eyepiece and an insertion part, for example. The shaft part 8 and the main body 6 are connected to one another in a sealed manner, for example glued, soldered or the like.

The proximal end of an optical fiber bundle that runs through the interior of the shaft part 8 in the longitudinal direction to the distal end 10 of the shaft part 8 can be fastened in a connecting piece on the main body 6 that serves to terminate a light guide (not shown).

Furthermore, an eyepiece socket (also not shown) can extend from the main body 6 , through which an optic runs, which is also guided through the shaft part 8 to the distal end of the urethroscope 2 . An eyepiece can be provided on the eyepiece socket at the proximal end of the optics.

The length of the shaft part 8 is, for example, 400 to 500 mm in a urethroscope 2 of conventional design. The outside diameter of the shaft part and the outside diameter of the outer metal tube should not exceed a maximum of about 4 mm. With such a cross-section of the outer metal tube, the result is essentially independent depending on the wall thickness, a certain rigidity of the pipe, which when the pipe is bent leads to an elongation of the material on the outside and a compression of the material on the inside (relative to the center point of the bending radius).

At its distal end, the shaft part 8 is sealed in a suitable manner, e.g. with a window for an optical system in the fiber channel 16 and with a sufficiently tight bond of the light guide 14 or light guides 14. The bond is made, for example, with an inflexible adhesive. The well-sealed shaft part 8 ensures that the optics arranged inside and the light guide(s) 14 are not impaired by water or steam penetrating when working with the urethroscope 2 or during sterilization.

The cross-sectional view 12 of 2 shows that the shank part 8 has a shank wall 20 of round cross-section which defines the outer circumference in a flexible section and which can preferably be designed as a metal tube. In the exemplary embodiment shown, the interior of the shaft part 8 enclosed by this shaft wall 20 accommodates two inner channels, the fiber channel 16 (also: optical channel) and the working channel 26. Both the fiber channel 16 and the working channel 26 can be designed as metal tubes. The fiber channel 16 encloses the optics, which transmits the viewed image from a lens arranged at the distal end 10 of the shaft part 8 to the eyepiece. The working channel 26 is designed as a free channel in which an instrument (for example a laser lithotriptor) can be advanced through the insertion part, the proximal laser generator of which is also not shown.

In the interior of the shaft part 8, two light guides 14 are also laid, which are preferably designed as optical fiber bundles and are used to illuminate the field of view. The light guides 14 are bonded with a flexible silicone adhesive that protects the light guides 14 from damage from pressure and friction. In the exemplary embodiment shown, the entire interior (not occupied by channels or light guides) of the flexible section of the shaft part 8 shown is additionally filled with a flexible adhesive 22 . According to the invention, this was achieved in that the flexible adhesive was injected into the flexible section of the shaft part 8 .

At the proximal end of the shaft part 8, the light guide 14 can be led out of the main body 6 via a light guide connection. There, a fiber optic connection cable can be connected to a cold light source, not shown.

3a and 3b each show a section through a distal, stiffened section of different shaft parts 8.

It can be seen that the in 3a shown shaft part 8 has an oval outer cross-section in a distal, stiffened section, while it - as in the background of 3a recognizable - has a flexible section with a round external cross-section proximal to this section. This in 3a The shaft part 8 shown is part of a 1-channel instrument, since the shaft part has a working channel 26 as can be seen.

It can also be seen that the 3b Shaft part 8 shown has a triangular outer cross-section with rounded corners in a distal, stiffened section, while - as in the background of FIG 3b recognizable - has a flexible section with a round external cross-section proximal to this section. This in 3b The shank part 8 shown is part of a 2-channel instrument, since the shank part can be seen to have two working channels 26 . The distal section of the shaft part 8 shown is stiffened by the oval or triangular external cross section.

In addition to the working channel(s) 26, the shaft parts have a fiber channel 16 in which an optical system can be inserted. A dilation nose 18 is also arranged on the shaft part. It can be seen that the light guides 14 essentially fill up the entire free space within the shaft part 8 .

Although the present invention has been described in detail on the basis of the exemplary embodiments, it is self-evident for the person skilled in the art that the invention is not limited to these exemplary embodiments, but rather that modifications are possible in such a way that individual features are omitted or other types of combinations of the individual features presented are implemented provided they do not depart from the scope of the appended claims. The present disclosure includes all combinations of the presented individual features.

Reference List

2

urethroscope

6

main body

8th

shaft part

10

distal end of the stem portion

12

Cross-section of the shaft part

14

light guide

16

fiber canal

18

dilation nose

20

shaft wall

22

flexible adhesive

24

wall of the working channel

26

working channel

Claims (10)

Medical endoscope with an elongate shaft part that is flexible at least in sections, through which at least one light guide having a large number of individual fibers runs in the longitudinal direction, characterized in that fibers of the light guide in a region in which they pass through a flexible section of the shaft part, by means of a flexible adhesive are bonded, fibers of the light guide being additionally bonded to the distal end of the shaft part and/or to the proximal end of the shaft part by means of an inflexible adhesive. Medical endoscope after claim 1 , characterized in that the flexible adhesive is a silicone adhesive. Medical endoscope one of the Claims 1 until 2 , characterized in that the endoscope is a urethroscope. Medical endoscope according to one of the Claims 1 until 3 , characterized in that the light guide is connected to the inner wall of the shaft part by means of the flexible adhesive. Medical endoscope according to one of the Claims 1 until 4 , characterized in that the free space within the flexible section or sections of the shaft part is at least partially filled with the flexible adhesive. Medical endoscope according to one of the Claims 1 until 5 , characterized in that the flexible adhesive and the inflexible adhesive are spaced from each other in the shaft part. Medical endoscope according to one of the Claims 1 until 6 , characterized in that the shaft part has a first, distal, stiffened section and a second flexible section proximally adjoining this first section. Medical endoscope according to one of the Claims 1 until 7 , characterized in that the first, stiffened section of the shaft part has a non-round cross-section. Method for assembling a medical endoscope according to one of Claims 1 until 8th , characterized in that it comprises steps in which (a) a light guide having a large number of individual fibers is wetted at least in regions with the flexible adhesive, (b) the adhesive is allowed to harden and (c) the light guide is then drawn into the shaft part . Method for assembling a medical endoscope according to one of Claims 1 until 8th characterized in that it comprises the steps of (a) threading an optical fiber comprising a plurality of individual fibers into the shank, (b) injecting the flexible adhesive into a portion of the shank, and (c) allowing the adhesive to cure.

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