Tissue cutter

A tissue cutter with forceps-like handles at its proximal end for actuating the cutter. The cutter includes a tube to receive cut-off pieces of tissue. A stripper strips the pieces of tissue from a cutting tool. A stripper rod, which is spring-loaded and subject to being locked and released moves the tissue into the tube, this operation being accomplished by completion of a cutting sequence.

BACKGROUND OF THE INVENTION 
The invention relates to a tissue cutter for medical purposes with 
forceps-like handles at the proximal end for actuating the cutting tool at 
the distal end by means of an outer shaft and an operating rod, whereby 
the outer shaft of the tissue cutter is constructed in tubular manner and 
internally at the distal end has a stripper for stripping the drawn-in 
pieces of tissue from the cutting tool. 
For the purpose of removing the cut tissue or pieces of bone from the 
instrument it was hitherto necessary to remove the instrument from the 
operating area after each cut, which is not only very time-consuming, but 
also very unpleasant for the patient. Particularly in laparoscopy the 
length of the operation was considerably increased by the frequent removal 
of the tissue cutter. The present tissue cutter has the important 
advantage relative thereto that there is no need for the frequent removal 
thereof for the purpose of removing cut tissue or bones. For this purpose 
the pieces of tissue are moved into the tubular shaft and are held there 
by the stripper by cross-sectionally saw tooth-shaped recesses in the 
inner wall of the shaft. Generally the endoscope shaft is sufficiently 
long to receive all pieces of tissue and bone resulting from an operation 
(German Utility Model 7 705 342). 
However, it may occur, particularly at the start of the operation, that 
specimens do not remain in the endoscope shaft and instead are displaced 
forwards together with the cutting tool, i.e. they remain attached to the 
latter. This is for example due to the fact that the pieces are only very 
small and cannot therefore be forced with the desired pressure into the 
shaft. 
It is also due to the fact that as a result of the adhesive power such 
small pieces of tissue adhere to the cutting tool. 
BRIEF SUMMARY OF THE INVENTION 
The problem of the invention is to obviate the above disadvantage and 
ensure that in all cases the specimens remain in the area of the shaft 
end, in particular through being reliably detached from the cutting tool. 
According to the invention this problem is solved by the tissue cutter of 
the type indicated hereinbefore. A stripper rod with a stripper at the 
distal end is arranged within the cutting tool and is loaded by a spring, 
and a locking mechanism is provided for releasing the spring-loaded 
stripper rod when the latter has reached its outermost distal position. 
Thus, by means of the stripper rod according to the invention and the 
stripping tool located thereon the specimen is in all cases removed from 
the cutting tool. When the cutting tool is displaced forwards again the 
specimen is held in its proximal position within the endoscope shaft by 
the stripper tool. Only when the cutting tool has reached its outermost 
distal position again is the stripper rod according to the invention moved 
in percussive manner forwards by the spring, so that due to its inertia 
alone the specimen remains in the shaft, i.e. it is detached from the 
stripper tool. 
According to a further development of the invention the stripper is 
constructed as a disc at right angles to the direction of movement. 
The size of the disc is naturally adapted to the internal diameter of the 
outer shaft, so that it is ensured that all specimens are held back in the 
shaft. 
It is also very advantageous for the stripper rod to be provided with a 
catch for engaging a spring-loaded stop member at the proximal end. 
The catch can be used to connect or disconnect the stripper rod and the 
instrument, when the cutting tool is in its outermost distal position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows the complete instrument in the assembled state with the two 
forceps-like handles 6 and 7 at the proximal end. Handle 7 can be pivoted 
about articulation 8, whilst handle 6 with its fulcrum point 10 is movable 
in the longitudinal direction of the instrument and is pivotable about 
articulation 9. Articulation 10 is connected in articulated manner with 
the operating rod 2 within the endoscope shaft 1. As can be seen at the 
left at the distal end of the instrument the operating rod 2 is fixedly 
connected with tool 3. 
If handle 6 is now moved to the right with respect to handle 7, the 
operating rod 2 and tool 3 can be moved backwards and forwards in the 
shaft 1 until tool 3 is completely within shaft 1, as shown in FIG. 2. The 
distal end 4 of shaft 1 is constructed as a counter-tool for cutting tool 
3. In addition, it is provided with a stripper having cross-sectionally 
saw tooth-shaped recesses, which act in the manner of barbs. Thus, the cut 
pieces of tissue can easily slide through from left to right, but are 
prevented from passing in the opposite direction together with tool 3 to 
the front again into the position shown in FIGS. 1 and 3 by the 
above-mentioned recesses. This is not shown in detail because the hitherto 
described tissue cutter forms part of the prior art. 
According to the invention additionally a stripper rod 11 with a stripper 
12 is provided in axially movable manner at the distal end within 
operating rod 2, of also FIGS. 5 and 6. It can be gathered from FIGS. 1 
and 2 that through the movement of handle 6 to the right stripper rod 11 
together with operating rod 2 are moved to the right to the distal end. 
FIG. 3 now shows that this position according to FIG. 2 is retained, 
although operating rod 2 with tool 3 has been moved forwards again to the 
distal end. This is due to the fact that stripper rod 11 with its catch 15 
has engaged in a spring-loaded stop member 16 in the area of articulation 
8 in FIG. 2, and does not therefore effect the following axial forwards 
movement of operating rod 2. 
FIGS. 4, 5 and 6 show details of the subject matter of the invention. Shaft 
1 according to FIG. 4 is provided in conventional manner with a bayonet 
catch 17, which is released by the corresponding counterpiece 18 according 
to FIG. 6. In addition stripper rod 11 has been removed from its mounting 
support within operating rod 2. Thus, rod 11 when in the mounted state is 
axially movable with respect to operating rod 2. 
To the left in FIG. 5 is is possible to see stripper 12, constructed in the 
form of a disc, at right angles to the axial direction of movement. The 
abutment 19 for spring 13 is located in the centre of rod 11. Further to 
the right it is possible to see the above-mentioned catch 15 and finally 
stripper rod 11 is terminated at the distal end by a disc 14. 
The subject matter of the invention will be explained hereinafter. 
In the mounted state stripper rod 11 is located in its axially movable 
position within the operating rod 2. If handle 6 is moved to the right 
according to FIG. 2, then shoulder 20 of operating rod 2 moves stripper 
rod 11 together with operating rod 2 to the right, so that the stripper 
rod is retracted in accordance with FIG. 2. Spring 13 is compressed, so 
that operating rod 2 is spring-loaded in the axial direction. At the end 
of the working traverse, rod 11 with its catch 15 engages in the proximal 
end 16 of the instrument, where there is a corresponding, not shown 
locking mechanism. Spring-loaded members of this type are known, so that 
no detailed description is necessary here. 
If handle 6 is now moved forwards according to FIG. 3, rod 11 remains in 
the indicated position. Only when cutting tool 3 has reached the furthest 
forward position is it possible to release the stop member 16 from catch 
15 either manually or by operating handle 6, so that now the rod is moved 
abruptly in a percussive manner to the left by spring 13 until it comes to 
rest in the position of FIG. 1. 
Thus, no additional actuation by the doctor is necessary. As a result of 
this percussive operation the disc-like stripper 12 is detached from the 
specimen which consequently remains at the distal end 4 of outer shaft 1. 
In the case of a plurality of successive actuations the various specimens 
are introduced successively into the outer shaft 1 by cutting tool 3 
together with stripper 12. 
The invention is not restricted to the represented embodiment. The general 
spatial concept comprises providing a stripper 12 with stripper rod 11 
which, by means of the arrangement of spring 13 and locking mechanism 15, 
can be displaced forwards in percussive manner, so that the disc-like 
stripper 12 is reliably released from the specimen and the latter does not 
continue to adhere to it.