Laparoscopic Hook Scissors

The present invention broadly relates to laparoscopic surgical instruments. More particularly, the invention relates to surgical instruments having end effectors in the form of scissors useful in a laparoscopy procedure which involves the lifting of a structure away from surrounding tissue prior to severing the structure by scissoring action.

The laparoscopy procedure has recently become a widely practiced surgical procedure. A laparoscopy procedure typically involves incising through the naval and through the abdominal wall for viewing and/or operating on the ovaries, uterus, gall bladder, bowels, appendix, although more recently, incisions and insertion of trocar tubes have been made in different areas of the abdomen and even in the chest cavity. Typically, trocars are utilized for creating the incisions. Trocar tubes are left in plane in the abdominal wall so that laparoscopic surgical tools may be inserted through the tube. A camera or magnifying lens is often inserted through the largest diameter trocar tube (e.g. 10 mm diameter) which is generally located at the navel incision, while a cutter, dissector, or other surgical instrument is inserted through a similarly sized or smaller diameter trocar tube (e.g. 5 mm diameter) for purposes of manipulating and/or cutting the internal organ. Sometimes it is desirable to have several trocar tubes in place at once in order to receive several surgical instruments. In this manner, organ or tissue may be grasped with one surgical instrument, and simultaneously may be cut or stitched with another surgical instrument; all under view of the surgeon via the camera in place in the navel trocar tube.

Previous to the present invention, laparoscopic tools have utilized scissor end effectors of the hook type which have hooked (scooped) blades for ensuring that the tips of the cutting blades come together before cutting action starts. The problem with the laparoscopic hooked scissors of the art is that the structure to be cut (e.g., a duct, vein, tendon, etc.) often gets trapped between the blades in such a manner that cutting is difficult and/or that the cut made is jagged (i.e., not clean). The applicants have determined that a primary reason for the difficulty in cutting with the hooked scissors of the art is that clean cutting requires that the cutting blades be forced into contact at preferably a single moving cutting point. Simple scissors are built in such a fashion that the blades are forced into contact at a single point by a torque acting from their pivoting point and arising from elastic deformation of the blades or some other resilient means at or near the pivoting point. The hook scissors of the art have been designed to have two cutting points where the edges of the scooped blades touch. The difficulty with this design is that it is difficult, if not impossible, to fabricate such scissors so that the torque acting from their pivot point causes both desired cutting points to be forced together. Indeed, such scissors are usually hand built with a minimum of resilience in their construction and fitted together with minimum operating clearance at the pivot point so that the two blades, while not being actually forced into contact at either of the intended cutting points, close with very little clearance. Such an arrangement, even when executed with skill, will often fail to cut materials with a fibrous or elastic nature, thereby causing the blades to separate (i.e., a lateral gap will form). Also, the action of the hook scissors of the art is such that the two cutting points start at the inner and outer ends of the blades and move to meet at the middle of the cutting area. This closing action causes fibrous and elastic material to bunch in the scissors, resulting in further force pushing the blades apart and inhibiting their cutting actions.

It is therefore and object of the invention to provide a hook scissors for laparoscopic instruments which is constructed to provide only a single moving point of contact between blades when actuated.

Another object of the invention is to provide laparoscopic hook scissors having hook elements at the distal ends of the blades, which hook elements do not contact each other during cutting action.

In accord with the objects of the invention, a hook scissors end effector device is provided for a laparoscopic instrument. The hook scissors end effectors generally comprise first and second blades, with at least one of the blades being pivotally engaged, and each blade comprising an elongate straight blade member with an integral transverse hook element at the distal end of the blade member. The hook elements each extend towards the other blade member and each hook element is offset from its blade member so that a narrow recess is provided between opposing first and second hook members upon closing of the first and second blade members. The elongate straight blade members provide a straight scissors cutting action therebetween so that the contiguously adjacent portions of the blade members gradually come together in a continuous bearing contact to effect a cutting action. While the hook elements at the distal ends of the blades effectively provide a hook which contains the object to be severed, the distal portions of the blade members do not establish contact with each other until the cutting action reaches the distal portion of the scissors.

A better understanding of the disposable laparoscopic hook scissors instrument of the invention, and additional advantages and objects of the invention will become apparent to those skilled in the art upon reference to the detailed description and accompanying drawings.

FIG. 1 is a side elevation view, partly in section, of a disposable laparoscopic instrument prior to insertion into a trocar tube, and, in partial phantom format, after insertion into a trocar tube;

FIG. 1a is a cross sectional view through the laparoscopic instrument of FIG. 1 at the indicated location;

FIG. 2 is an enlarged side elevation view, of the hook scissors end effectors of the invention in an open position;

FIGS. 3, 3(A) and 3(B) are enlarged elevation, plan and side views of one of the blades of the device of FIG. 2;

FIGS. 4, 4(A) and 4(B) are enlarged elevation, plan and front elevation views of the device of FIG. 2 in the closed position;

FIG. 5 is an enlarged fragmentary perspective view of a distal portion of a blade member of FIG. 2; and

FIG. 6 is a perspective view of the clevis element usable with the hook scissors device of FIG. 2.

With reference to FIG. 1, (and FIG. 1A), a disposable laparoscopic surgical instrument is indicated at 10. The disposable laparoscopic surgical instrument 10 includes an aluminum tube 15 surrounded by a peripheral insulating shrink wrap layer of plastic 20, a clevis means 30, hook scissors end effectors 40, actuating means 50, and a push rod 60. The clevis means 30 is preferably a separately formed aluminum piece which fixedly engages aluminum tube 15. The clevis 30 also engages the manipulating members 90, 92 of the end effector 40. Member 90 is pivotally engaged to clevis 30 at pivot pin 45 and member 92 is fixedly engaged to the clevis 30 at pin 45 and post 46. End effector 40 is preferably formed of a cobalt base alloy, although it can be formed of other materials such as, e.g., stainless steel, if desired. The push rod 60, which is preferably formed of stainless steel, is engaged at its distal end 65 to the end effector 40, as hereinafter more fully described, and is connected at 70, at its proximal end, to a manually operable actuating means 50. For purposes herein, the "distal end" of the instrument 10 or any part thereof, is the end closest to the surgical site and distant from the surgeon, while the "proximal end" of the instrument 10 or any part thereof, is the end most proximate the surgeon and distant the surgical site.

In use, the laparoscopy instrument 10 is inserted with the blades 90, 92 of the end effector 40, in the closed position, into trocar tube 80, as indicated at the arrow 85 of FIG. 1. The distal portion of the instrument 10 passes through the trocar tube 80 into body incision 100. Upon the distal portion of the laparoscopy instrument 10 exiting the trocar tube 80, one or both of the blades 90, 92 can be opened and closed as indicated at 105 by reciprocal motion of push rod 60 which results from operation of the manual actuating means 50. As is discussed in more detail in Ser. No. 07/680,392, the clevis effectively helps to translate the reciprocal motion of the push rod 60 into the end effector means action indicated at 105.

Additional detail regarding the laparoscopy instrument 10 may be obtained by reference to previously incorporated U.S. Ser. No. 07/680,392. It is noted, however, that the preferred embodiment of the hook scissors is a single acting tool with one of the end effector blades stationary.

With reference to FIG. 2, the hook scissors end effector of the present invention is shown at 110 in an open position having a pivotally rotatable blade member 90 which is rotatable about pivot pin 45 of clevis 30 as more fully described hereinafter. Blade member 92 preferably also engages the pivot pin 45. However, because blade member 92 is provided with a post 46 which engages a hole 46' in clevis 30, blade member 92 is fixed in position with respect to clevis 30. Blade members 90, 92 are held in a tight bearing contact by pivot pin 45 which extends through holes 145 of the blade members and which engages the clevis 30. Each blade member 90, 92 has a respective straight cutting edge 201, 203 which extends along blades 90, 92 to their terminal distal portions 205, 207 remote from the pivotal engagement at 45.

The hook scissors end effectors of FIG. 2 are comprised of substantially identical blade members 90, 92 (minor differences such as the provision of a projection or post 46 for insertion into a hole 46' in the clevis, and the elimination of a hole 146 for a connecting means being provided where one blade member is fixed). As seen in FIG. 3, each elongate straight blade member 90, 92 has a transverse integral hook element 209, 211. The hook elements 209, 211 extend toward each other in the open position of FIG. 2 and are offset from their respective blade members as indicated at 213, 215 of FIG. 3 to provide a narrow recess 217 (FIG. 4B) between the opposing hook elements when the blade members are closing or in the closed position. An even narrower recess 219 is formed between each blade member 90, 92 and the adjacent hook member 209, 211 of the other blade member 90, 92 when the blade members are closing. As shown in FIG. 4, the terminal portions 221, 223 of the hook elements 209, 211 of blade members 90, 92 are preferably rounded at 225, 227, and the edges of hook elements 209, 211 are preferably blunt, i.e. not sharpened as compared to blade edges 201, 203 which are sharpened and in close bearing contact.

In use, blade 90 can be opened relative to blade 92 as shown in phantom in FIG. 2, such that a tissue, vein, duct, or other object 300 can be gently grabbed by the hook element 209 of blade 92. By closing blade 90 relative to blade 92 as shown in FIG. 2, object 300 is encompassed by the non-sharpened, non-contacting, blunt edged, parallel, opposed hook elements 209, 211. With the object 300 so encompassed (or with hook element 209 grabbing the object as in the case of a vein or other small object), the object can be pulled to a location where positive identification by imaging or other equipment is achieved. When the identity of the encompassed object is identified, and cutting is desired, the cutting operation along cutting edges 201, 203 proceeds by pivotal movement of blade member 90. With the device of the present invention, a clean cut is provided by cutting edges 201, 203 as blade member 90 and 92 contact with each other along a continuously moving bearing contact point 310'-310''-310'''-310''''-310'''''-310''''', thereby avoiding entrapment of tissue between laterally displaced blade members. Also, since cutting proceeds from one end only, the accidental cutting of an object which can happen in the prior art hook scissors is avoided during the procedure of grabbing the object, as the opposed hook elements 209, 211 do not act to cut.

Typical dimensions for the hook scissors end effectors in accordance with the present invention are as follows for a device made of stainless steel:

Turning to the perspective view of FIG. 6, a preferred configuration of the clevis 30 for use with the present invention is seen. The clevis has a knurled rod-like proximal portion 15 for mating with the end of the aluminum tube 15, and a pivot-supporting U-shaped distal portion 32 for holding the end effector means 40 comprising members 90, 92. The proximal portion 34 of the clevis is preferably hollow, as indicated at 33, to permit the push rod 60, with its flattened terminal portion 62 to extend therethrough. The distal portion 32 of the clevis 30 is provided with a pivot pin 45 which is generally perpendicular, i.e. transverse, to the legs 36 of the clevis. In addition, where a single acting end effector is provided, one of the legs of clevis 30 is provided with a hole 46'. The fixed end effector blade 92 of the single acting instrument is provided with a transverse or lateral protrusion 46 which extends into hole 46'. As a result, fixed blade 92 is fixed relative to the clevis 30 by engagement of protrusion 46 in hole 46' and by engagement of hole 145 at pivot pin 45. On the other hand, the pivoting blade member 90 is engaged at through hole 146 by a metal link member 97 to push rod 60 which is engaged to link member 97 at through hole 98. Upon actuation of push rod 60, blade member 90 moves pivotally around pin 45 to provide the scissor action indicated at 105' while blade member 92 remains stationary. Double acting hook scissors are easily obtained by eliminating the protrusion 46 and hole 46', and by substituting an additional metal link member as is disclosed in previously incorporated U.S. Ser. No. 07/680,392.

There has been described and illustrated herein laparoscopic hook scissors. While particular embodiments of the invention have been described, it is not intended that the invention be limited exactly thereto, as it is intended that the invention be as broad in scope as the art will allow. Thus, while a scissors having a particular single pivot actuating means was described, it will be appreciated that different arrangements such as described in copending U.S. Pat. No. 5,171,258 can be utilized to provide a scissors with additional cutting leverage. Also, while a scissors with particular dimensions and comprised of particular materials was described, it will be appreciated that other materials could be utilized and that the scissors can have different dimensions. Therefore, it will be apparent to those skilled in the art that other changes and modifications may be made to the invention as described in the specification without departing from the spirit and scope of the invention as so claimed.