Surgery – Instruments – Forceps
Reexamination Certificate
2000-08-02
2002-07-16
Truong, Kevin (Department: 3731)
Surgery
Instruments
Forceps
C606S170000
Reexamination Certificate
active
06419688
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to a medical tubular-shaft instrument. The present invention relates to a medical instrument of the kind, which generally comprises an elongated tubular shaft, at least one movable tool at the distal end, further at least one movable grip element at the proximal end, and lastly an elongated force transmitting element, the distal end whereof is operatively connected to the at least one tool and the proximal end whereof to the at least one movable grip element, the force transmitting element extending through the tubular shaft.
Tubular-shaft instruments of this kind are used in minimally invasive surgery as surgical instruments, in order to perform surgical procedures through a small incision in the body under endoscopic monitoring. These tubular-shaft instruments are equipped with different functions for different surgical procedures that are to be performed in the human or animal body.
A “tubular-shaft instrument” for the purposes of the present invention is thus understood to be, for example, a forceps for cutting and/or grasping and/or, for example, also a needle holder. The at least one tool can thus be configured, for example, in the form of a movable jaw part that has a blade which coacts in cutting fashion with a blade of a second movable or stationary jaw part. In the case of a needle holder, the at least one movable tool has a configuration which makes it possible with that tool to hold a needle in the surgical field and to guide it in order to create a suture so as to join tissue.
For actuation of the at least one movable tool, there is provided at the proximal end of the tubular-shaft instrument at least one movable grip element that is operatively connected to the at least one movable tool via an elongated force transmitting element, for example in the form of a pull rod. A movement of the movable grip element thus brings about a movement of the at least one movable tool at the distal end of the tubular shaft in order to perform the corresponding function, for example cutting or holding and guiding the needle through the tissue.
In the context of minimally invasive surgery, it is occasionally necessary to configure such tubular-shaft instruments with a tubular shaft diameter that is approximately 3 mm or less. Such small tubular shaft diameters are desirable, for example, for surgery on small children or also for procedures in specific surgical areas, for example in the head region.
With the known tubular-shaft instruments, in particularly those having a diameter of approximately 3 mm or less, the force transmitting element is adapted in terms of its diameter to the inside diameter of the tubular shaft, i.e. the outside diameter of the force transmitting element is approximately the same as the inside diameter of the tubular shaft, so that the force transmitting element completely fills up the interior of the tubular shaft.
The disadvantage of this configuration is that when the force transmitting element is in place, the interior of the tubular shaft cannot be adequately flushed, since sufficient passage for a flushing liquid is not present between the force transmitting element and the tubular shaft. Since, however, such miniaturized tubular-shaft instruments cannot be disassembled, or at least cannot easily be disassembled, in such a way that the force transmitting element can be removed from the tubular shaft for cleaning—since the join between the at least one movable tool and the force transmitting element on the one hand, and the force transmitting element and the at least one movable grip element on the other hand, is not detachable or not easily detachable—this means that the known tubular-shaft instruments cannot be adequately cleaned. Contaminants that collect in the interior of the tubular shaft during an operation therefore cannot be removed to the point that these tubular-shaft instruments can meet stringent sterility and hygiene requirements.
In order to improve the cleaning properties of these tubular-shaft instruments, consideration has been given to equipping the force transmitting element with an outside diameter that is less than the inside diameter of the tubular shaft, so that a sufficient flushing space remains between the force transmitting element and the tubular shaft. It has proven to be particularly disadvantageous in this context, however, that despite its rigid configuration, the tubular shaft bends in response to tensile forces transferred from the force transmitting element to the at least one movable tool. The tubular-shaft instrument becomes unusable, however, if the tubular shaft is bent. The same disadvantageous effect also occurred if, instead of a small-diameter force transmitting element with a round cross section, a tension strip flattened on both sides was used. A force transmitting element in the form of a flat tension band also resulted in a loss of stability in the tubular shaft.
It is therefore the object of the invention to develop a tubular-shaft instrument of the kind cited initially in such a way that the tubular-shaft instrument can easily be cleaned, by flushing the interior of the tubular shaft, while the force transmitting element is in place, whereas the stability of the tubular-shaft instrument against bending of the tubular shaft continues to be guaranteed.
SUMMARY OF THE INVENTION
According to the present invention this object is achieved, by a tubular-shaft instrument, comprising an elongated tubular shaft having a distal end and a proximal end, and having an inner wall; at least one tool disposed at said distal end of said shaft; at least one movable grip element disposed at said proximal end of said shaft; an elongated force transmitting element having a distal end which is operatively connected to said at least one tool, and a proximal end which is operatively connected to said at least one movable grip element, said force transmitting element extending through said tubular shaft, wherein said force transmitting element, at least in its region extending through said tubular shaft and at least locally, reaches radially at at least three circumferential points as far as said inner wall of said shaft and between said three circumferential points has a clearance from said inner wall, and in its remaining portions extending through said tubular shaft has a clearance from said inner wall at least over part of its circumference.
What is thus provided according to the present invention is firstly that the force transmitting element, at least in its region extending through the tubular shaft, continuously has, at least over part of its circumference, a clearance from the inner wall of the tubular shaft, so that the interior of the tubular shaft has a flushing cross section sufficient for cleaning even when the force transmitting element is in place. Also provided according to the present invention is that the force transmitting element, at least locally in axial terms, reaches radially as far as the inner wall of the tubular shaft at at least three circumferential points. This is because, especially in the case of tubular-shaft instruments having a tubular shaft diameter of approximately 3 mm and less, it has become evident that with such thin tubular shafts the force transmitting element also assumes the task of stabilizing the tubular shaft against bending when large tensile forces are being transferred. In the case of the tubular-shaft instrument according to the present invention, this is ensured by the configuration of the force transmitting element by the fact that at least locally, at three circumferential points it reaches radially as far as the inner wall of the tubular shaft, and thereby stabilizes the tubular shaft. In order to ensure that a flushing liquid can pass through in these segments or portions as well, the force transmitting element has in these segments, between the circumferential points toward the inner wall of the tubular shaft, a clearance for the passage of a flushing liquid. Whereas it has been found with the approaches
Anders Fridolin
Bacher Uwe
Karl Storz GmbH & Co. KG
St. Onge Steward Johnston & Reens LLC
Truong Kevin
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