Application part for an endoscope

The disclosure relates to an application part for rigid or flexible endoscopes having a viewing channel and a working channel extending parallel to the viewing channel, with the working channel being equipped with a guide as well as a defined stop for a fiber optic waveguide, which can be inserted and coupled with a laser light source, and the working channel having optics for concentrating the laser light emerging from the fiber optic waveguide onto a punctiform area. The part of the working channel surrounding the punctiform area is formed as shock wave reflector. Further, a flushing channel is provided, the outlet opening of which is at least partially directed onto the face of the optics from which the light emerges.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates to an application part for use in either rigid or 
flexible endoscopes and having a viewing channel, and a working channel 
extending parallel to the viewing channel. The working channel is equipped 
with a guide as well as a defined stop for an insertable fiber optics 
waveguide which can be coupled to a laser light source. 
A device of this nature is known, for example, from DEP No. 29 45 080. This 
device is used for endoscopic laser irradiation of urinary bladder tumors 
with the laser light emerging from the light waveguide being directed 
directly onto the tissue to be irradiated. The object of the present 
invention is to provide an application part for rigid or flexible 
endoscopes, with which fragmentation of concrements, such as bladder, 
urinary bladder, kidney or gall stones within living bodies, becomes 
possible. 
The objective of the invention is achieved through an application part for 
flexible or rigid endoscopes wherein the working channel has an optics 
arrangement for concentrating the laser light emerging from the fiber 
optic wave guide onto a punctiform region and, further, the working 
channel extends beyond the optics arrangement toward the punctiform region 
to form a shock wave reflector. Moreover, a flushing channel is provided 
having an outlet opening which is at least partially directed toward the 
face of the optics arrangement. 
A device for fragmenting a solid body is described in the earlier 
application No. P 35 06 249.5. This device, however, does not serve as an 
application part for a rigid or flexible endoscope. 
The application part according to the invention can, for example, be either 
integrated into a rigid endoscope or placed onto a flexible endoscope. 
With an endoscope equipped in this way, bladder, urinary, kidney or gall 
bladder stones can be directly fragmented into extremely small fragments 
with shock waves, without the shock waves having to pass through the body, 
and with the stones under observation continuously throughout the 
procedure. The fragments can then be flushed out without problems or they 
can be passed naturally. 
Below the invention is described in greater detail in conjunction with an 
embodiment represented schematically in the figures, in which

DETAILED DESCRIPTION 
The application part shown in FIG. 1 consists essentially of a cylindrical 
part 1 with three channels extending parallel, of which one is a viewing 
channel 2, another a working channel 3, and the last a flushing channel 4. 
The working channel 3 has a guide 31 for a fiber optic waveguide 5, onto 
which a stop ring 6 is clamped or fastened with adhesive agents. The fiber 
optic waveguide 5 is slid into the working channel 3 until the stop ring 6 
rests against a specially formed part 7 of the guide 31. In this manner, 
the position of the end face 8 of the fiber optic waveguide 5 within the 
working channel 3 is precisely defined. To prevent the sliding of the 
fiber optic waveguide 5 within the working channel 3, the latter is 
equipped with a clamping device 9. 
The fiber optic waveguide 5 is connected at the inlet side with a laser 
light source known per se and therefore not illustrated. The laser light 
emerging from the end face 8 of the fiber optic waveguide 5 is bundled by 
an optics arrangement including lenses 10 to 14 onto a punctiform area 15. 
For this purpose, the optics arrangement is formed as a reduction optics 
arrangement with a reproduction ratio of 1:4 to 1:10, which reproduces the 
end face 8 in the region 15 correspondingly reduced. 
The light intensity coupled into the waveguide 5 as well as the 
reproduction ratio of the optics are so adapted to each other that in the 
region 15 a so-called "breakdown-effect" occurs, as described in the above 
mentioned German patent application No. P 35 06 249.5 or in the 
dissertation by Dipl.-Phys. Jurgen Munschau "Theoretische und 
experimentelle Untersuchungen zur Erzeugung, Ausbreitung and Anwendung 
laserinduzierter StoBwellen" ("Theoretical and experimental investigation 
concerning generation, diffusion and application of laser-induced shock 
waves."), TU Berlin, Berlin 1981. The shock wave generated by this 
"breakdown-effect" is focused by a spherical or elliptical shock wave 
reflector 16. When using a spherical reflector it is positioned such that 
the focus coincides with the focal point of the optics in region 15. When 
using an elliptical shock wave reflector with two focal points, one focal 
point coincides with the focal point of the optics in region 15, while the 
other focal point is directed onto the surface of the concrement to be 
fragmented. The illustrated embodiment has a spherical shock wave 
reflector and the area 15 lies on the plane defined by the outer border 17 
of the shock wave reflector 16 in such a way that the endoscope can be 
placed directly onto the concrement to be fragmented. Thus, in each 
instance only fragments of the outer layer of the concrement are removed. 
This ensures that only extremely small fragments are generated, which can 
either be flushed out or passed by natural means. 
Since the generated shock waves exert great stress on the optics, in 
particular on the lens 14, at least this lens 14 and, because of the high 
light intensities, possibly also the field lens 10 are made from quartz 
glass or sapphire. When shaping the lens 14 it is best if here a 
concave-convex lens is employed, with the curvature of the concave face 
corresponding approximately to that of the shock wave reflector 16. In 
this way, the lens 14 partially assumes the function of a shock wave 
reflector. Further, the lens 14 must be sealed gas and liquid-tight as 
well as shock-proof against the shock wave reflector 16 and the sealing 
material 18 must be made from a particularly elastic material. Silicon is 
an especially well suited material for this purpose. 
Since during treatment the front lens 14 must be kept clean, the flushing 
channel 4 has at its distal end a bent nozzle 19, which directs a jet of 
flushing fluid directly onto the lens 14 (see FIG. 3). 
With the currently available fiber optic waveguides and optics working 
channel diameters of 2 to 3 mm, the entire diameter of the application 
part, which is circular in cross section, is approximately 5 to 7 mm. The 
cross sectional area can be correspondingly reduced if the outer contour 
is even further adapted to the envelope 20 of channels 2, 3, and 4 (see 
FIG. 2).