Surgery – Instruments – Forceps
Reexamination Certificate
2001-08-24
2003-10-21
Thaler, Michael H. (Department: 3731)
Surgery
Instruments
Forceps
Reexamination Certificate
active
06635071
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a surgical grasping and holding forceps.
Surgical grasping and holding forceps are used to grasp and hold and object between the mouth parts. Objects of this kind are, for example, spherical muslin sponges, in which case the term “sponge forceps” is used. In many laparoscopic operations, dissection sponges or rod sponges are required; these are used to remove tissue fluids or blood. One principal area of application is the actual dissection technique using the spherical sponge clamped and held between mouth parts. Sliding dissection is used to separate tissue layers atraumatically, and this reveal underlying structures during an operation. In these cases the sponge forceps operates simultaneously as a dissection forceps. Other objects that can be clamped in grasping and holding forceps of this kind are, for example, needles for making a suture.
The objects, i.e. for example a spherical sponge or a needle, are clamped into the holding forceps by the instrument nurse, and handed to the surgeon. The latter guides the holding forceps, for example with the sponge, through a trocar and dissects. After use, the holding forceps is withdrawn from the trocar and, if necessary, spherical muslin sponges are once again clamped in place. The same applies to the making of surgical sutures.
RELATED PRIOR ART
Grasping, holding, and dissection forceps are known from the catalog “Endoskopische Chirurgie [Endoscopic surgery], 2nd edition, 1/94, section 4, page DG 5, ‘Präparier- und Fa&bgr;zangen’ [Dissection and grasping forceps]” of Karl Storz GmbH & Co., Tuttlingen, Germany.
Locking of the handle elements in a specific pivoted position relative to one another, and thus also locking of the mouth parts in a specific closed position, is brought about via a snap catch. The catch is configured as a notched bar that is arranged on one of the two handle elements. Corresponding projections which can snap into the notches are present on the other handle element. A spring or a lever holds the handle elements in the snapped-in or locked state. A plurality of locked positions are possible.
It has now been found, in practical utilization of this kind of surgical grasping and holding forceps, that during handling an attempt is made to clamp the object being held, for example a spherical sponge, as firmly as possible in the grasping forceps. The movable handle element is configured as a lever, the lever axis being represented by the hinge axis at which that movable handle element is articulated on the other handle element. The distance between the hinge axis and the point at which the movable handle element is joined to the actuation element that is to be displaced is substantially shorter than the distance from the hinge axis to the finger loop, arranged at the outer end of the handle element, into which is inserted the finger of a hand which grips the surgical grasping and holding forceps. The ratio is approximately 10:1, i.e. the closing force of a hand (approximately 10 kp) is magnified tenfold by the lever effect, i.e. to approximately 100 kp.
Because of the aforementioned practice of clamping a spherical sponge as firmly as possible in the grasping forceps, the lever mechanism means that the mouth parts are acted upon by large forces which can result in the mouth parts being bent and/or in damage to the mechanism, so that the sponge is no longer held firmly and can be lost during dissection. In such a case the lost sponge must be looked for within the body and picked up again. The lock in the form of the toothed-rack catch is also exposed to the high stress of this holding pressure, creating the risk that clumsy handling might cause the snap catch to unsnap, thus releasing the lock and opening the mouth parts.
It was also found in practical use that the handle elements protruding approximately at right angles from the shaft at the proximal end of the shaft greatly restrict the surgeon's mobility, so that for dissection purposes the forceps is gripped in the region of the transition from the shaft to the stationary handle part. The laterally protruding handle parts impede or interfere with the surgeon during dissection. In dissection operations of this kind, the snap catch which extends transversely between the two handle elements can inadvertently release, so that the objects held by the mouth parts, for example a spherical sponge or a needle, can be lost in the body.
DE-A-4 216 971 recites a forceps having two mouth parts for grasping and holding tissue or the like. At least one mouth part is pivotable relative to the other by axial adjustment of an actuation bar using a handle. The closed position of the mouth parts and the handle can be fixed in position by a lock, and the closing force of the forceps mouth parts can be set to different values.
EP-A-0 688 534 describes a hollow-shaft surgical instrument having a shaft and a push/pull rod displaceably mounted therein for moving a tool at the end of the shaft, and a handle element arranged coaxially with the shaft at the other end of the shaft in which a handle is mounted pivotably about a rotation axis running perpendicular to the longitudinal shaft axis, movement of the handle being transferable via linkage means to the push/pull rod. Also provided is a resilient snap element which, upon movement of the handle out of an initial position, is moved past a snap catch, thereby engages thereinto, and as a result prevents the handle from moving backward. To simplify the design, the snap element and the snap catch form a recirculating catch in which the snap element is moved, at the end of the handle's linear stroke, completely past the snap catch, and during the return movement moves past the back side of the snap catch into the initial position.
EP-A-0 512 725 discloses a medical instrument in which a mechanism for opening and closing the mouth parts is acted upon by spring force in such a way that the mouth parts are thereby pressed in the closing direction. Opening of the mouth parts can be controlled by way of an actuation element that is displaced against the force of the spring. When the actuation element is released, it is displaced by the spring and the mouth parts are thereby pressed toward one another in accordance with the force of the spring.
U.S. Pat. No. 5,431,675 discloses an interlock mechanism for a medical instrument in which a lever linkage is connected to a rotatable control cam. As a result of an eccentric arrangement of the lever on the cam and a corresponding configuration of the lever linkage, mouth parts can be moved positively into a very specific final closed position, and there hold the part present between the mouth parts with a specific holding force.
U.S. Pat. No. 5,409,478 recites a grip of a medical instrument on which a laterally protruding lever is articulated. This lever is connected via a further lever to an actuation element for moving the mouth parts. The actuation element itself is pressed by the force of a spring in one direction. The laterally protruding articulated lever can be laid by manual force against the grip, in the course of which the actuation element is displaced via the second lever against the force of the spring. The result is to overcome a spring catch, ensuring that when the articulated lever is released, it does not spread apart again.
U.S. Pat. No. 5,383,895 discloses a surgical instrument, configured as a grasping forceps, whose actuation element, which is provided for spreading and closing the mouth parts, can be moved back and forth against the force of a spring. The spring force acts on the actuation element in such a way as to press the mouth parts in the closing direction.
U.S. Pat. No. 5,211,655 discloses a medical forceps which is equipped with a lock with which the mouth parts can be locked in a very specific position.
It is the object of the present invention to create a surgical grasping and holding forceps which allows secure handling, and which in particular eliminates the possibility of damage
Boche Hartmut
Scherieble Hans
Karl Storz GmbH & Co. KG
St.Onge Steward Johnson & Reens, LLC
Thaler Michael H.
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