Gynecological or urological endoscope

Abstract

Gynecological or urological endoscope (1) with a shaft tube (3), the cross-section of which has an elongated inner contour, which forms a first circular arc (5) with a first radius (r') in a first contour region and a second circular arc (6) with a second radius (r) in a second contour region that is greater than the first radius (r'), which circular arcs (5, 6) lie with their centers (M, M') at a distance equal to the sum of their radii (r, r') and are connected on both sides of the axis of symmetry (S) of the inner contour running through the centers (M, M') by tangential contour regions (7), which at their ends each merge tangentially into the circular arcs (5, 6), wherein an optic (8) formed in an optical tube is arranged in the second circular arc (6), which optic is secured by a holder (4) against displacement in the direction of the first circular arc (5), characterized in thatthat the holder on the shaft tube (3) forms at least one inwardly shaped recess (4) which is arranged on one of the tangential contour regions (7) adjacent to the transition to the second circular arc (6), and wherein the cross-section of the shaft tube (3) has an elongated inner contour which forms circular arcs (5, 6) in end regions of the contour and laterally tangential contour regions (7) which connect the circular arcs (5, 6).

Description

[0001] The invention relates to an endoscope of the type mentioned in the preamble of claim 1.

[0002] A generic endoscope is described in DE 8416392 U. It is an endoscope for working in the ureter or through the ureter in the kidney.

[0003] Typically, the shaft is designed with an elongated cross-section and can comprise two elongated subchambers with a circular cross-section, one of which is designed as a larger chamber to accommodate an optical system and the smaller as a working channel for a working instrument such as a biopsy forceps or a stone removal instrument. The remaining spaces in the cross-section can be used as an irrigation channel.

[0004] The very limited space available must be taken into account. Hysteroscopes are gynecological endoscopes that are inserted into the uterus through the very narrow and sensitive cervical canal. Ureteroscopes are urological endoscopes that are inserted through the very narrow ureter, which has only very limited expandability. Therefore, the outer circumference of the shaft of these endoscopes must be kept as small as possible. This results in the elongated cross-sectional shape of an inner contour with circular arcs at the ends and tangents on both sides, as shown in the cited document.

[0005] The cited known design is particularly advantageous because it solves an additional problem, namely the mounting of the optics in the shaft tube. In earlier designs, the shaft tube contained only the optics and the instrument. These were freely arranged and could move, for example, in the event of vibrations within the shaft tube. This could lead to the optics touching the instrument, hindering precise handling of the instrument.

[0006] The cited construction uses an inner tube mounted in the shaft tube as a holder to secure the position of the optics, which surrounds either the space for the instrument or the space for the optics and thus separates these spaces from each other, so that unwanted contact is reliably prevented.

[0007] However, the inner tube located inside the shaft tube has the disadvantage of reducing the interior space. Even with a very thin inner tube wall thickness, cross-sectional losses occur, which are unacceptable given the very critical space constraints of this type of endoscope. These losses would have to be compensated for by reducing the cross-section of the optics or the working instrument, or they would be at the expense of the irrigation channel. Thus, a design dilemma exists here.

[0008] An undesirable narrowing of the interior space and the associated loss of cross-section also result from the use of an inner shaft additionally inserted into the outer shaft of an instrument according to US 2007 / 0270788 A1, in which the inner shaft has two circular arc sections that are connected by two tapered wall sections.

[0009] The publications DE 36 03 758 A1 and DE 43 35 783 A1 address the topic of contour guidance on elongated shafts or tube sections of instruments for medical endoscopy. DE 36 03 758 A1 specifically concerns the arrangement of spacers on the guide sleeves of a cutting electrode for resectoscopes. DE 43 35 783 A1 shows a shaft with an elongated cross-sectional shape and an inner contour with circular arcs connected by tangents on both sides. The problem of undesired displacement of tools arranged in the shaft, such as an optical system inserted into the shaft of the instrument, and the optimization of internal cross-sections to avoid cross-sectional losses when conveying rinsing fluids through narrow channels, is not addressed in these publications.

[0010] The object of the present invention is to solve the described problem.

[0011] This object is achieved according to the invention with the features of the characterising part of claim 1.

[0012] According to the invention, the holder is designed as an inwardly shaped recess on the shaft tube. This recess is located at the end of one of the tangents before the transition to the larger circular arc, i.e., where the optics are located. The recess thus blocks the optics from moving toward the instrument. The optics are thus prevented from moving toward the instrument in the desired manner.

[0013] The invention essentially achieves the same result as the cited known design. However, the invention eliminates the need for an inner tube, thus avoiding the resulting loss of cross-sectional area.

[0014] A recess according to the invention can be point-shaped. However, according to claim 2, it is preferably designed as a bead that runs parallel to the shaft tube. This results in more precise mounting of the optics.

[0015] A recess serving as a support only at one tangent is sufficient for the intended support purposes. However, the advantageous two-sided support according to claim 3 is better and more precise.

[0016] The cross-section of the shaft tube could be designed differently along its length. However, according to claim 4, its inner contour is preferably constant along the length of the shaft tube. This results in a simpler construction and less impact on the available cross-section.

[0017] Advantageously, according to claim 5, the wall thickness is constant. This ensures a simple construction and small external dimensions.

[0018] Claim 6 lists the types of endoscopes for which the invention can be advantageously used. In gynecology, these are the hysteroscope for working in the uterus through the very narrow and pain-sensitive cervical canal; in urology, the cystoscope for working in the bladder; the ureteroscope for working beyond the bladder in the very narrow ureter; and the nephroscope for working beyond the ureter in the kidney.

[0019] Claim 7 contains advantageous dimensions for endoscopes according to the invention.

[0020] The drawing illustrates the invention schematically using a hysteroscope as an example. It shows: Fig. 1 a side view of a hysteroscope according to the invention, Fig. 2 an enlarged section along line 2 - 2 in Fig. 1 and Fig. 3 the representation of the Fig. 2 in schematic form and Fig. 4 - 7 highly schematic cross-sections of a hysteroscope with the corresponding flow rates.

[0021] Fig. 1 shows the side view of a hysteroscope 1 of largely conventional construction with a shaft tube 3 extending distally from a main body 2, which in Fig. 2 in enlarged cross-section along the line 2 - 2 in Fig. 1. Characteristic features are laterally arranged depressions in the form of beads 4, which in the exemplary embodiment extend essentially over the entire length of the shaft tube 3.

[0022] As in particular Fig. 2, the cross-section of the shaft tube 3 has an elongated inner contour, which forms circular arcs 5, 6 in the end regions of the contour and laterally tangential contour regions 7 that connect the circular arcs 5, 6. The circular arcs are of different sizes and enclose sub-chambers extending over the length of the shaft tube 3, of which the larger sub-chamber is traversed by an optic 8, while the smaller sub-chamber, indicated by a dashed line, forms the working channel 9 through which an instrument 10 can be inserted.

[0023] If you compare Fig. 1, it can be seen that the optics 8 extends through the main body 2 and carries an eyepiece 11 at its proximal end. The instrument 10 arranged in the working channel 9 is designed as a biopsy forceps in the illustrated embodiment and has a correspondingly designed jaw part 12 at the distal end. The working channel 9 passes through the main body 2. From its proximal end, the instrument 10 can be inserted, the proximal end of which is shown as a forceps handle 13.

[0024] It must be emphasized here that the representations, especially those of the Fig. 1 are not to scale. The height H of the cross section, which is Fig. 2 and which is usually used for size specifications in instruments of this type, is typically 5.25 mm for a shaft tube length 3 of the order of 200 mm. The cross-sectional shape of the Fig. 2 corresponds to the desired ratios.

[0025] The Fig. The optic 8 shown in Figure 2 essentially consists of the outer tube shown, which, like the shaft tube 3, is usually made of stainless steel suitable for endoscopic devices. Inside the outer tube of the optic 8 is a Fig. 2, an optical system not shown is arranged, which may consist of a plurality of rod lenses arranged one behind the other, or possibly also of a fiber optic bundle. The instrument 10, which is indicated by the hatching in Fig. 2 is indicated as an integral rod, can for the purposes shown a forceps shaft preferably be designed with an outer tube or hose in which a pull rod is arranged to be longitudinally displaceable.

[0026] How Fig. As shown in Figure 2, the optic 8 is positioned within the shaft tube 3 with only a slight undersize. If the optic 8 shifts in position relative to the shaft tube 3, it will come into contact with the shaft tube. Therefore, the optic 8 can only shift slightly into the working channel 9. Interference caused by contact with the instrument 10 is thus avoided.

[0027] This is achieved by the beads 4, which form elongated depressions at the point of transition of the tangential contour areas 7 to the larger circular arc 6. The simplified standard shape without beads, as represented, for example, by the prior art cited at the beginning, would allow for significantly larger displacements of the optics, which would lead to contact with the instrument 10, up to and including its more or less complete blockage.

[0028] The circular arcs 5 and 6 of the shaft tube 3 each form a center point M and M' through which the symmetry axis S of the inner contour of the cross section runs. The inner contour of the cross section corresponds to the cross section of the inner surface of the shaft tube 3. At the points of the circular arcs 5 and 6, the inner contour has the radius r' and r, respectively, as in Fig. 2. The outer radii at these points are also shown as R' and R.

[0029] In order to keep the cross-section of the shaft tube as narrow as possible, the circumference of the working channel 9 and that of the optics 8 touch each other. Therefore, as Fig. 2 shows the centers M and M' at a distance equal to the sum of the radii r and r' of the circular arcs 5 and 6 respectively.

[0030] You can see in the opposite Fig. 2 slightly different representation of the Fig. 3, that symmetrically to the symmetry axis S between the shaft tube 3 and the optics 8 or the working channel 9 two circular cross-sectional areas Q remain free, which for clarification in Fig. 3 are shown hatched.

[0031] Since in this embodiment a channel separation between an inlet and an outlet channel is not provided, these spaces Q can be used together as a rinsing channel, for example for the inflow of rinsing fluid into the surgical area.

[0032] For the connection of the flushing channel to the outside, a liquid connection 14 is provided in the illustrated embodiment, which Fig. 1 with the corresponding shut-off valve.

[0033] This can be done intermittently, for example, with the channel being used alternately for inflow or return flow. However, it is also possible, for example, to use the beads 4 as an external return flow channel, as proposed in DE 10 2004 043 460 A1 or WO 2009 / 083123 A1.

[0034] In the cross-section of the Fig. 3, the flow resistance of the cross-sectional area Q usable for flushing purposes is particularly important. However, this depends not only on the area but, given the given narrow conditions, also very strongly on the exact shape of the cross-section.

[0035] The findings of hydrodynamics regarding fluid flow in pipelines must be taken into account here. Essentially, this shows that the flow resistance at a point in the pipe cross-section is determined by the distance from the wall. The farther a cross-section is from the walls, the lower the flow resistance.

[0036] In the cross-section of the Fig. 6, the flow resistances are very high at the cross-sectional areas around the optics 8, i.e. in a narrow gap with directly adjacent walls. It is immediately apparent that in the cross-sectional areas Q ( Fig. 3) the wall distances are large and therefore the flow resistances are small.

[0037] For these reasons, the cross sections Q in Fig. 3 is shown as round. Although somewhat larger, approximately triangular cross-sections are available, the corner areas are hardly usable due to their proximity to the wall.

[0038] Even if one attempts to take these hydrodynamic insights into account, theoretical considerations are difficult for the expert in this field to achieve their goal, as the geometric relationships of the cross-sectional shapes in question are too complicated. Therefore, the precise cross-sectional shape was optimized through experiments.

[0039] The Fig. 4, Fig. 5, Fig. 6 and Fig. 7 shows the results of tests with different cross sections. The cross section of the Fig. 7 corresponds to the cross-section in the state of the art cited at the beginning. Fig. 6 shows the cross section of the present invention. The Fig. 4 and Fig. 5 show other possible cross sections.

[0040] Fig. 6 shows the cross section of the Fig. 2 in a highly schematic representation. It shows the shaft tube 3 and the cross-sections of the optics 8 and the working channel 9 located therein, as well as the two beads 4. In addition to the cross-sectional representation, a bar chart shows the achievable flow rate for rinsing fluid, as determined in the comparison test in ml / min.

[0041] If you look at the cross-section of the Fig. 6 or the Fig. 2, it can be seen that the flow cross-section is essentially given in the cross-sectional areas Q, which are in Fig. 3. The figures show additional free cross-sectional areas between the optics 8 and the shaft tube 3. There are also free cross-sectional areas around the instrument 10. However, these are located in unfavorable positions, have high resistances, and therefore contribute little to the fluid flow.

[0042] The cross-section of the Fig. 7 was used only for comparison purposes. It is not suitable for this case because it does not provide adequate support for the optics, as all other cross-sectional shapes do.

[0043] In addition to the cross-sectional views of the Fig. The flow rates are shown in Figures 4 - 7. As expected, the flow rate in the case of Fig. 4 very low and in the case of Fig. 7 is very high. What is surprising, however, is the comparison of the Fig. 5 and Fig. 6. Contrary to what a visual estimate suggests, the cross-section of the Fig. 6 significantly cheaper than the Fig. 5.

[0044] When comparing the Fig. 4 - 7 it must also be pointed out that the outer contour of the cross-section of the Fig.7 must not be exceeded even with the other cross-sectional shapes. Increasing the outer diameter would require greater stretching of the cervix, causing considerable pain and risking injury.

[0045] The invention was explained using the example of a hysteroscope, i.e. an endoscope for working in the uterus, through the cervical canal.

[0046] The invention is also excellently suited for use in urology when working with a ureteroscope beyond the bladder in the very narrow and sensitive ureter, or through it with a ureterorenoscope in the kidney.

[0047] For the ureter and the cervical canal, the requirements for the sheath circumference are virtually the same. Suitable endoscopes can essentially be used in both areas.

Claims

[1] Gynecological or urological endoscope (1) with a shaft tube (3), the cross-section of which has an elongated inner contour, which forms a first circular arc (5) with a first radius (r') in a first contour region and a second circular arc (6) with a second radius (r) in a second contour region, which is greater than the first radius (r'), which circular arcs (5, 6) lie with their centers (M, M') at a distance equal to the sum of their radii (r, r') and are connected on both sides of the axis of symmetry (S) of the inner contour running through the centers (M, M') by tangential contour regions (7), which at their ends each merge tangentially into the circular arcs (5, 6), wherein an optic (8) formed in an optical tube is arranged in the second circular arc (6), which optic is secured by a holder (4) against displacement in the direction of the first circular arc (5), characterized bythat the holder on the shaft tube (3) forms at least one inwardly shaped recess (4) which is arranged on one of the tangential contour regions (7) adjacent to the transition to the second circular arc (6), and wherein the cross section of the shaft tube (3) has an elongated inner contour which forms circular arcs (5, 6) in end regions of the contour and laterally tangential contour regions (7) which connect the circular arcs (5, 6). [2] Endoscope according to claim 1, characterized by that the recess is designed as a bead (4) running parallel to the shaft tube (3). [3] Endoscope according to one of the preceding claims, characterized by that a recess (4) is formed on each tangential contour area (7). [4] Endoscope according to one of the preceding claims, characterized by that the inner contour of the shaft tube (3) is constant over its length. [5] Endoscope according to one of the preceding claims, characterized bythat the wall thickness of the shaft tube (3) is constant over its length and circumference. [6] Endoscope according to one of the preceding claims, characterized by that the endoscope is a hysteroscope, a ureteroscope, a nephroscope or a cystoscope. [7] Endoscope according to one of the preceding claims, characterized by that the outer radius (R') of the shaft tube (3) in the area of ​​the first circular arc (5) is a maximum of 1.1 mm, the outer radius (R) of the shaft tube (3) in the area of ​​the second circular arc (6) is a maximum of 1.75 mm and the height (H) of the shaft tube (3) is a maximum of 5.25 mm.

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