Abstract:
Disclosed is a four-jawed combinational scissor-grasper surgical tool for use in laparoscopy. Cutting and grasping functionalities are respectively enabled via movement of a pair of such specially contoured jaw members sliding against or splaying apart from the other pair. Also disclosed are means for achieving selectable interlocking of jaw members and mechanical linkage for their actuation by human user.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to art of surgical tools and more specifically to the architecture and operation of a bi-functional scissor-grasper tool capable of being used in minimally invasive surgical procedures such as laparoscopy. 
     BACKGROUND OF THE INVENTION 
     Past few decades have seen vast development as to surgical procedures—minimally invasive surgery being one of the prime advances of this era. Minimally invasive surgeries, such as arthroscopic surgery and laparoscopic surgery, recently have become widely practiced surgical procedures. Such procedures have gained rapid popularity and generally are preferable over the traditional open surgery which requires cutting large incisions through the skin, muscles and membranes to open and expose the body cavity, thereby necessitating longer hospitalization stays and prolonged recovery periods. In minimally invasive surgery, small incisions are made into which tubular conduits, such as cannulae and trocars, are inserted and directed to the site of the operable internal organ or tissue. One or more surgical instruments are introduced, each through individual tubular conduits in order to perform the surgical procedure. It would be obvious to the reader that said minimally invasive surgical procedures including arthroscopy, endoscopy and laproscopy owe their realization to special tools capable of access to intended site of surgery via small incision made to body of patient and operation of which allows precise performance of intended site-specific surgical manipulations. 
     Cutting, grasping, suturing, cauterization, distension, stapling form commonality of operations in surgery. Minimally invasive surgery tools of art do provide individually for such functions. However, due to the singularity of function accorded by such tools available, the interchange of tools amidst operations and efforts, time required for such becomes unavoidable, besides causing opportunity for complications during repeated insertion and removal of different tools. 
     In laparoscopic surgery, specialized long thin tools are inserted via air-tight ports fixed on the CO 2  inflated abdomen of the patient. The operation area as seen by the endoscope is displayed on an external display where the surgeon views it. Since only a few thin holes are created for inserting tools, this type of surgery results in fewer injuries to the patient, faster healing periods and less cosmetic damage. This type of surgery requires specialized tools that are characterized by their long shafts (usually around 300 mm) and thin cross sections (usually 5-8 mm dia). These tools come in various end-tips, such as scissors, blades, graspers, etc. Procurement/maintenance costs, sterilization requirements of additional equipment are other problems faced by the medical fraternity. Thus, development of minimum invasive surgical tools capable of plural functionality, yet maintaining accuracy, precision and ease of use, are pressing needs of art. 
     There have been some attempts for resolving said needs of art. Various forms of laparoscopy tools, housings for positioning instruments, extendible blades, multifunctional scissor jaw designs and the like find mention in the art. Many devices which are used commonly for grasping or cutting objects have two elements which can be moved towards one another and away from one another. The elements have surfaces which may be blunt or sharp so that an object positioned between them may be either grasped or cut when the elements are moved towards one another. Examples of such devices include tongs, tweezers, forceps, scissors, guillotines, and wire cutters. Such devices can also be adapted to dissect tissue, for example, by placing the elements of the device into or next to an object and then causing the elements to splay apart thereby dissecting the object. However, these designs have been found to suffer from drawbacks critically affecting their intended function. 
     U.S. Pat. No. 6,024,744 discloses a combined bipolar scissor and grasper. The instrument disclosed in this patent is a combined bipolar electrosurgical cutting and grasping instrument where the grasping surfaces are contained within the shape of a standard surgical scissor. Accuracy of operation is defined by precise positioning of these portions at site of manipulation. However, being contained within same arm, the cutting and grasping portions are invariably in same angle of motion, thus present risk of accidental cuts or clamps. Also, pivoting of the tool while being inserted is not without risk due to exposed cutting edges. 
     U.S. Pat. No. 5,397,325 discloses a surgical suturing device which has a tubular elongated shaft terminating into a jaw assembly at the distal end and a handle assembly at the proximal end thereof. The jaw assembly includes a first jaw member pivotally connected to a second jaw member. An actuator rod extending longitudinally within the length of said shaft is connected at its proximal end to said handle assembly and is pivotally connected at its distal end to said jaw assembly. The underside of said first jaw member is provided with a cupped recess having a wheel assembly disposed therein. The wheel assembly includes a needle mount for securely retaining a needle and is configured such that the needle lies within the cupped recess when the jaw members are closed and can be deployed in a protracted position away from the first jaw member when the jaw members are in an open position. In operation, the suturing device offers superior control over both the needle and the tissue to be sutured. 
     The above mentioned invention suffers from drawback of limited degree of operation due to configuration wherein only one jaw is movable and the other fixed. The said single shaft device presented finds utility for function of suturing having adequate needle control, however, does not offer means to grasp and stabilize the tissue, which is slippery by nature thus mandating that the tissue tending to evade needle carrier manipulation must be grasped by a second instrument. As a result, the surgeon encounters difficulty in controlling and positioning both the needle and the tissue simultaneously, and the patient can suffer complications such as frayed tissue, errant punctures, inadequate stitches, extended surgical duration, hemorrhaging, and the like. 
     U.S. Pat. No. 5,509,923 describes a device for dissecting, grasping and/or cutting an object has at least two elongate elements at least a portion of at least one of the elements is formed from a pseudoelastic material, preferably a pseudoelastic shape memory alloy. End portions of the elements can be moved away from one another and then toward one another to dissect, grasp and/or cut an object with the elements. In certain embodiments, the device further comprises an actuating means and at least a portion of the elements and/or the actuating means is formed from a pseudoelastic material. The device is intended for applications including dissecting, grasping and/or cutting objects located in difficult to reach areas, within the body during surgery. However, the cutting/grasping members of this tool are pseudoelastic and thus, allow limited degree of choice while deciding on the angle of cut and portion of tissue being grasped. Unintentional nicks and pinches cannot be ruled out are limitations in rotational ability of the tool proposed. 
     Laparoscopic Scissor Grasper, a product by Interventional and Surgical Innovations LLC is a minimally invasive surgery tool that can both cut and grasp with aid of two jaws having mated via serrations along their inner surfaces. The jaws separate along two axes apart and sideways to provide grasping and cutting functions respectively. However, this design is subject to certain shortcomings as the grasping serrations are invariably exposed while shearing. Also, pivoting of the jaws about their longitudinal axis is not possible. Also, for cutting edge to work, the chamfered edges necessarily need to press against each other. This pressure is enabled by forging a slight curvature in cutting arms being pressed at pivot by means of rivet or other tightening means. Over period of use, this arrangement looses its original construction leading to either loss of pressure of cutting arms or distancing of said cutting arms which ultimately leads to firstly loss of cutting functionality and secondly, presence of two sharpened (chamfered) edges which act as knives and can cut whether intended or not. Such occurrence, is thus compromise to application intended. 
     U.S. Pat. No. 5,133,727 discloses radial jaw biopsy forceps which feature a multi element head having a fixed blade juxtaposed between two grasper jaws having mated serrations along their internal edges for grip. However, this design too has shortcomings of limited scope for movement and accidental cuts to material in space between the grasping arms while performing delicate functions. 
     By and large, innovations cited have not been able to overcome the problems of the art. Design of a pluri-functional device for achievement of surgical operations is a pressing need of the art. The present inventor has undertaken specific research and has arrived at novel construction and operability of a device for addressing said problems of art. The following brief description presents one non-limiting embodiment of constructing and performing the present invention. 
     OBJECTS OF THE PRESENT INVENTION 
     It is an object of the present invention to provide a single shaft four-jawed laparoscopic instrument with suitable components and linkages that provide for cutting-grasping bi-functionality and construction capable of performing intended bi-functionality in a manner that allows infinite rotational ability about its longitudinal axis. 
     It is another object of the present invention to provide a single shaft laparoscopic instrument wherein cutting functionality is enabled via shear forces achieved at edges of jaws by their motion against each other thus avoiding open blade design altogether. 
     It is another object of the present invention to provide a four-jawed single shaft laparoscopic instrument wherein construction of jaws comprise integral mechanical interlocking system that allows for selectable locking of two pairs of jaws each configuration serving the cutting or grasping functionalities. 
     It is another object of the present invention to provide a bi-functional single shaft laparoscopic instrument which reduces the amount of instrumentation necessary for surgical procedures in which both cutting and grasping is required. 
     It is another object of the present invention to provide a bi-functional single shaft laparoscopic instrument which reduces the amount of dexterity needed by a surgeon performing a surgical procedure in which both electrosurgical cutting and grasping is required. 
     It is another object of the present invention to provide a bi-functional single shaft laparoscopic instrument which is easily amenable to common art pre-surgical sterilization techniques. 
     It is another object of the present invention to provide a bi-functional single shaft laparoscopic instrument which is capable of repeated use thus decreasing the amount of medical waste generated in surgical procedures. 
     It is yet another object of the present invention to provide for a minimally invasive surgical tool which efficiently combines functions of cutting, grasping and overcomes overall drawbacks of prior art devices. 
     It is also an object of the present invention to achieve accurate fine cuts or shear-free firm grasp whenever intended. 
     It is also an object of the present invention to provide grasping and cutting surfaces which are independent of each other. 
     These and further objects shall present themselves to the reader upon description presented herein below along with accompanying drawings. 
     SUMMARY OF THE PRESENT INVENTION 
     In accordance with principles of the present invention, a single shaft laparoscopic instrument is proposed which has cutting/grasping bi-functionality. Said bi-functionality is enabled by achieving two user-selectable configurations of four specially constructed jaw members. Design of these jaw members comprises an integral mechanical interlocking system and linkage which, when operated by the user, results in two movable elements each comprising a pair of jaws. In one configuration where linkage allows for sliding of the movable elements against each other, cutting function is achieved. In other configuration where linkage allows for movement of the movable elements away from and towards each other, the grasping functionality is achieved. 
     The invention may be more fully understood by reference to the cited figures and details of exemplary embodiments. Alternative embodiments of the invention as claimed, and providing the benefits of the novel concepts of the invention, are contemplated and will be obvious from the explanations hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the preferred embodiment of the present invention showing the jaws in the closed position locked in the scissor configuration. 
         FIG. 2  is a perspective view of the preferred embodiment of the present invention showing the jaws in the closed position locked in the scissor configuration, but with two of the jaws not visible, so as to show the inner locking mechanism of the instrument. 
         FIG. 3  is a perspective view of the laparoscopic instrument proposed by the present invention with a magnified view of the four-jawed tip shown in inset. 
         FIG. 4  ( a,b,c ) are schematic representation of inter-play between two jaw pairs when in grasping configuration. 
         FIG. 5  ( a,b,c ) are schematic representation of inter-play between two jaw pairs when in cutting configuration. 
         FIG. 6  ( a,b,c ) are side, front perspective and back perspective views of jaw element  002 / 004  of the laparoscopic instrument proposed by the present invention. 
         FIG. 7  ( a,b,c ) are side, front perspective and back perspective views of identical jaw element  001 / 003  of the laparoscopic instrument proposed by the present invention. 
         FIG. 8  illustrates the hinge, described as element  005  in  FIGS. 4 and 5   
         FIG. 9  illustrates the connecting link that enables force to get transmitted to jaw elements  001  and  003 . 
         FIG. 10  illustrates the inner shaft that connects to the connecting link shown in  FIG. 9 . 
         FIG. 11  illustrates the hinge member that resides within the distal end of the inner shaft. 
         FIG. 12  illustrates the pin that allows the connecting link to hinge with jaws  001  and  003 . 
         FIG. 13  illustrates the shifter shaft that engages the jaw elements  002  and  004  in order to push them forward or pull them backward in order to respectively convert the tool from the grasper mode to scissor mode or the other way round. 
         FIG. 14  illustrates the outer holder of the tool that holds all the jaws together on the hinge  005 , and attaches to the outer shaft  009 . 
         FIG. 15  illustrates the side view of the proposed instrument in the grasper configuration, with the jaws in open position. Outer holder is hidden in this view. 
         FIG. 16  illustrates the side view of the proposed instrument in the grasper configuration, with the jaws in closed position. Outer holder is hidden in this view. 
         FIG. 17  illustrates the side view of the proposed instrument in the scissor configuration, with the jaws in closed position. Outer holder is hidden in this view. 
         FIG. 18  illustrates the side view of the proposed instrument in the scissor configuration, with the jaws in open position. Outer holder is hidden in this view. 
         FIG. 19  illustrates a close-up perspective view of the inner mechanism of the instrument in the scissor configuration with the jaws in closed position. Outer holder is hidden in this view. 
         FIG. 20  illustrates a close-up perspective view of the inner mechanism of the instrument in the grasper configuration with the jaws in closed position. Outer holder is hidden in this view. 
         FIG. 21  illustrates a perspective view of the inner mechanism of the instrument in the grasper configuration, with the jaws in closed position and the connecting links visible. Outer holder and shifter shaft are hidden in this illustration. 
     
    
    
     The invention may be more fully understood by reference to the cited figures and details of exemplary embodiments. Alternative embodiments of the invention as claimed, and providing the benefits of the novel concepts of the invention, are contemplated and will be obvious from the explanations hereinafter. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The laparoscopic procedure generally involves creating small incisions through the navel and through the abdominal wall for viewing and operating on internal areas of the body, such as the uterus, ovaries, gall bladder and appendix. Typically, a trocar tube is introduced through the navel incision for receiving a camera, magnifying lens or other fiber optic device for viewing the surgery. One or more additional trocar tubes are introduced through incisions in the abdominal wall such that laparoscopic surgical tools can be inserted through the tube(s) for manipulating, cutting and/or suturing an internal organ or tissue. In this manner, while viewing a video monitor via the fiber optic device positioned in the navel trocar, the surgeon can grasp an organ or tissue with one surgical tool and simultaneously cut or suture with another surgical device. 
     The evolution of minimally invasive surgery has given rise to the need of single-shaft surgical instruments which can be inserted through a trocar and easily manipulated by a surgeon. These instruments are fashioned such that they can be inserted lengthwise through the trocar and comprise hand-held controls on the proximal end thereof to operate the distal, tissue-manipulating end of said instrument. Single shaft devices must have a sufficiently small diameter so that they can be inserted into a trocar tube and guided to the operative tissue site. Typically, such instruments are designed to perform one function, such as grasping and stabilizing tissue, cutting tissue, holding a suturing needle or pulling a suturing needle through tissue, suctioning and irrigating the fluids, cauterizing the tissue, coagulating blood vessels and so on. A major drawback to minimally invasive surgery is that it requires exceptional motor coordination to grasp and stabilize an organ or tissue with one surgical tool and performing a cutting or suturing procedure on said organ or tissue with a second surgical device, all while viewing a two dimensional video monitor. This disadvantage is particularly acute in performing a laparoscopic suturing procedure. 
       FIG. 1  is a schematic side perspective view of the four jawed tip of the laparoscopic instrument proposed by the present invention. Also,  FIG. 2  illustrates elements structurally integral to the jaws of the laparoscopic instrument proposed by the present invention which provide for interlocking action. Explanation as to construction of the laparoscopic tool subject of the present invention is now attempted referring to both these figures. The combinational scissor-grasper tool  000  comprises a bullet nosed end comprising four independent jaw elements  001 ,  002 ,  003  and  004 . Said jaw elements are in operational association with a single hinge  005  and can lock into one another by positive locking mechanism enabled by mated protrusions and depressions corresponding to protrusion  006  and depression  007  along respective inner surface of each adjacent arm-in-pair. This mechanism ensures that when motion is delivered at the hinge, at all times, a specific combination of arms moves together. 
       FIG. 3  illustrates magnified view of the four-jawed tip of the laparoscopic instrument proposed by the present invention. As illustrated therein, the four jawed tip  000  is key novel feature of the present invention capable of performance between both cutting and grasping functionalities via actuation of controller  008 . 
       FIGS. 4  ( a,b,c ) and  5  ( a,b,c ) are schematic representation of inter-play between two jaw pairs when in grasping and cutting configurations respectively. When viewed from its tip with the tool being oriented such that its hinge  005  hosting the jaw elements  001 ,  002 ,  003  and  004  is parallel to the floor (horizontal), locking of jaw  001  with  004  and jaw  002  with  003  respectively to each other results in grasper configuration of the tool. In same orientation, locking of the left side jaws  003  and  004  and right side jaws  001  and  002  respectively to each other results in the scissor configuration of the tool  000 . 
       FIG. 6  ( a,b,c ) are front, perspective and back views of jaw element  002 / 004  of the laparoscopic instrument  000 . It may be seen that  010  is a depression into which the extension  021  illustrated later in FIG.  7 . a  enters while the instrument is in the scissor configuration. Generally referring to  FIGS. 6 to 17 , it may be seen that the shape associated with the depression  010  is intended to mate with shape associated with extension  021  so that the two elements can snugly slide into one another.  011  is an arc section having its geometric centre at point  012  which is geometrically mimicked on the inner arc of extension  021  thus allowing the extension  021  to slide over arc section  011  smoothly. This motion is later described in  FIG. 15 . Points  012  and  013  determine the end-points of slot  027 . The hinge  005  fits into the slot  027 . Along the slot  027  jaws  004  and  002  can slide backward and forward such that either points  012  or  013  align with central axis of hinge  005 , to enable the instrument to function as a grasper or as a scissor, respectively. Jaws  004  or  002  can rotate about hinge  005  either about point  012  or point  013 . Arcs  014  and  015  define a slot  020 . The arc  014  has its geometric centre at point  013 , while the arc  015  has its geometric center at point  012 . Protrusion  038  is positioned within the slot  020 . Arcs  015  and  016  define the handle  028 . The arc  016  has its geometric centre at point  013 . This handle gets positioned into the depression  039 . When the instrument shifts from grasper to scissor position, the shifter shaft  043  moves forward, towards the distal direction. During this forward motion, the proximal vertical surface  046  of the depression  039  pushes against the surface  016 . At the same time, the distal surface  048  pushes against surface  014 . This pushes the jaws  004  and  002  forward, towards the distal direction such that they slide on hinge  005  along their respective slots  027  taking them from being hinged about point  012  to being hinged about point  013 . As a result of this motion, the protrusion  021  in jaws  001  and  003  gets inserted into depression  010  in jaws  002  and  004  respectively, thus locking jaw  001  to  002  and jaw  003  to  004 . During the same motion, the protrusion  006  in jaws  001  and  003  slides out of the depression  007  in jaws  004  and  002  respectively, thus removing the lock between jaws  002  and  003  and between jaws  001  and  004 . This is the scissor configuration. When the instrument shifts back from scissor to the grasper configuration, the shifter shaft  043  moves backwards, towards the proximal end. During this motion, the distal vertical surface  047  of depression  039  engages with the surface  015 . This pulls the jaws  004  and  002  backwards, towards the proximal direction such that they slide on hinge  005  along their respective slots  027  taking them from being hinged about point  013  to being hinged about point  012 . As a result of this motion, the protrusion  021  in jaws  001  and  003  gets removed from depression  010  in jaws  002  and  004  respectively, thus unlocking jaw  001  from  002  and jaw  003  from  004 . During the same motion, the protrusion  006  in jaws  001  and  003  slides into the depression  007  in jaws  004  and  002  respectively, thus engaging the lock between jaws  002  and  003  and between jaws  001  and  004 . This is the grasper configuration. Thus, the protrusion  021  and depression  010  form a male-female pair to lock the device in the scissor configuration. The protrusion  006  and depression  007  form another male-female pair to lock the device in the grasper configuration. This switching mechanism between grasper and scissor configurations is shown between  FIG. 16  to  FIG. 17  as a side view and also between  FIG. 20  and  FIG. 19  as a close-up perspective view. 
     When the instrument is in the scissor configuration, the jaws  004  and  002  rotate about the point  013  on hinge  005 . In this configuration, the shifter shaft  043  has kept the jaws  004  and  002  pushed in this position. Hence, the surfaces  046  and  048  slide over surfaces  016  and  014  respectively. As the jaws  004  and  002  rotate about point  013 , it is essential that the arcs  014  and  016  have their geometric centers at point  013 . When the instrument is in the grasper configuration, the jaws  004  and  002  rotate about the point  012  on hinge  005 . In this configuration, the shifter shaft  043  has kept the jaws  004  and  002  pulled in this position. Hence, the surface  047  slides over surface  015 . As jaws  004  and  002  rotate about point  012 , it is essential that the arc  015  has its geometric centre at point  012 . 
     While shifting between scissor and grasper configurations, a single stroke motion engages one lock and disengages the other. The serrated surfaces  017  of jaws  004  or  002  and serrated surfaces  026  of jaws  001  and  003  are used for the grasping action. The distance between each tooth of the serrated surfaces  017  and  026  is greater than or equal to the distance between points  012  and  013 . While the tool jaws are in the closed position and the tool needs to be shifted between scissor and grasper configurations in either direction, this particular distance between the teeth on serrated surfaces  017  and  026  ensures that jaw  004  can slide over jaw  003  and jaw  002  can slide over jaw  001 , without letting the teeth physically interfere with each other. 
     According to another aspect of the present invention, edge  018  of jaws  004  or  002  is hardened and angled to create a sharp shearing edge. As shown in FIG.  5 . b  and  FIG. 18 , the edge  018  in jaw  004  moves against the edge  018  of jaw  002  to create the necessary shearing action required for the instrument to function as a scissor. 
     The serrated surfaces  017  and  026  are physically distinct and independent of the shearing edge  018 . This makes it possible to pick a great variety of grasping serration independently of a variety of scissor edge. Thus, a large number of combinations of different scissor and grasper types are possible to be incorporated in the instrument. 
     According to another aspect of the present invention, the handle  028  is created with a step  019  such that the depression  039  can be accommodated with the protrusion  038  positioned in the slot  020 . 
     The protrusion  021  is of a shape comprising an arc with the geometric centre at point  023 . This curvature also matches with the curvature of depression  010 . The depression  022  is of a shape comprising an arc with the geometric centre at point which is offset towards the distal end of the tool from point  023  by a distance that is equal to the distance between points  012  and  013 . This is also the distance by which the shifter shaft  043  moves while switching between the scissor and grasper mechanisms. Point  023  is the position of a hole in jaws  001  or  003  in which the hinge  005  resides. Jaws  001  and  003  always rotate about the axis through point  023 . 
     The connecting link  034  hinges to the jaws  001  and  003  at the hole  024  using pin  037 . Pin  037  can be in the form of a rivet that joins holes  033  and  024 . A step  025  accommodates the thickness of the connecting link  034 . Inner shaft  045  has a means of connecting with link  034  by a pin  031  at holes  032  and  035 . The pin  031  can be in the form of a rivet. 
     The entire system of the inner shaft  045  connected to jaws  001  and  003  by means of connecting links  034  hinged respectively at  032  and  033  by pins  031  and  037 , is shown in  FIG. 21 . The jaws  001  and  003  are forced to open by a simple parallelogram mechanism when the inner shaft  045  is moved forward in the distal direction. The connecting links  034  and the distance between points  023  to  024  on jaws  001  and  003  form the segments of this parallelogram mechanism. The user&#39;s action at element  008  creates this required motion in  045 . When the proposed surgical tool is in the grasper configuration, the protrusion  006  in jaws  001  and  003  locks in with depression  007  in jaws  004  and  002  respectively, thus locking jaws  001  and  004  together on one hand, and jaws  002  and  003  on the other. At this time the protrusion  021  in jaws  001  and  003  and depression  010  in jaws  002  and  004  are no longer engaged. When the jaws  001  and  003  are forced to open up by the parallelogram mechanism movement initiated by the user acting on inner shaft  045 , they also, in turn force jaws  004  and  002  to move along with them respectively. This creates the grasper configuration as shown in  FIG. 15  and FIGS.  4 . a ,  4 . b ,  4 . c.    
     When the tool is in the scissor configuration, the protrusion  021  in jaws  001  and  003  locks in with depression  010  in jaws  002  and  004  respectively, thus locking jaws  001  and  002  together on one hand, and jaws  004  and  003  on the other. At this time the protrusion  006  in jaws  001  and  003  and depression  007  in jaws  004  and  002  respectively are no longer engaged. When the jaws  001  and  003  are forced to open up by the parallelogram mechanism movement initiated by the user acting on inner shaft  045 , they also, in turn force jaws  002  and  004  to move along with them respectively. This creates the scissor configuration as shown in  FIG. 18  and FIGS.  5 . a ,  5 . b ,  5 . c.    
     Thus, when the instrument is in the grasper configuration, jaw  004  locks with jaw  001  while jaw  003  locks with jaw  002 . On the other hand, when the instrument is in the scissor configuration, the jaw  004  locks with jaw  003  while jaw  001  locks with jaw  002 . 
     A step  036  is created at the distal tip of inner shaft  045  in order to accommodate the thickness of connecting link  034 . The combined widths of the section  036  and two instances of link  034  are accommodated by pin  031  within the cut out gap  040  of shifter shaft  043 . This in turn must fit within the cut out gap  041  of outer holder  044 . In this outer holder  044  the hole  042  holds the hinge  005 . 
     A means to provide for the backward and forward movement of the shifter shaft is created. Any standard method to achieve this in a user-friendly manner would work. Other requirements of a surgical instrument, such as the ability rotate and fit within a 5 mm diameter, are also fulfilled. 
     According to another aspect of the present invention, the surfaces involved in grasping and cutting are independent of each other. Hence they may be sharpened, knurled, and formed independently for optimal performance. 
     Since both scissor and grasper operate about the same common hinge  005 , there is no inherent need for a 90° rotation about the tool&#39;s axis for a shift of configuration. 
     As described hereinabove, the mechanism for interlocking of jaw elements comprises male and female locking elements. Said interlocking elements are completely internal to the jaws themselves and thus do not interfere with the surgical environment. 
     According to another aspect of the present invention, the mechanism to shift between the grasper and scissor configurations is also contained completely internal to arm of the tool. It has so been designed to allow the tool to be manufactured within a 5 mm diameter. It should be appreciated that the instrument can be provided with a different shape of jaws to perform other actions besides straightforward grasping and cutting. Different types of graspers, scissors can be incorporated to this mechanism. The actuation of the instrument may be carried out by either the means of a regular handle operated by hands or it can be motorized to be applied in a robotic setting. In either case the mechanism of the front tip does not change. 
     If the jaw members and internal mechanism members are coated with appropriate insulation layers, the function of bipolar cauterization may also be added into the tool. The bipolar cauterization will occur between the jaw elements when the instrument is in the grasper configuration. 
     According to yet another aspect of the present invention, the mechanism to shift between the grasper and scissor configurations operates with a strictly linear motion along the axis of the tool. Inner and outer shafts of the main shaft body  009  are separable and thus, allow for rotation along the longitudinal axis. This allows for the tool to be rotated infinitely clockwise or anticlockwise about the axis of its main shaft body  009  and thus enable a 360° field of operation. 
     According to another aspect of the present invention, it is intended by the present inventor to make the device of the present invention amendable to controllers of common art, thus negating design of customized control architecture and/or user interfaces. This also means easy migration between tools for surgeons. 
     Thus, it would be now evident to the reader that the user interface or controlling means is same for both cutting as well as grasping functions and that the selection of function is enabled via actuation of a switch which controls interlocking of pairs of jaws of the device proposed by the present invention in accordance with functionality required. This switch may be selected among common art easy switching mechanisms such as turning knobs, trigger or toggle levers. Thus, the user has ability to migrate from one mode of operation to other with single stroke of switch and without having to remove/reinsert in body of patient being operated. Further, the scissor grasper combination can be made able to withstand infinite rotation of the tool along its longitudinal axis using a common art thumb-wheel. As common art controllers are utilized, the user maintains same tactile feel and dexterity while adapting to use of the proposed tool. 
     According to other embodiments of the present invention, the inner shafts of the tool are constructed to allow disassembly and reassembly to the main outer shaft by means chosen among press-fit, threading/screw mechanism or key-slot mechanism. This makes it possible to easily autoclave or sterilize the tip of the proposed instrument. It also allows for just the tip to be replaced without having to replace the handle or outer shaft. 
     According to another embodiment of the present invention, a cleaning port may be introduced in the shaft of the proposed laparoscopic tool for allowing sterilization and multiple use thereafter. 
     As will be realized, the present invention is capable of various other embodiments and that its several components and related details are capable of various alterations, all without departing from the basic concept of the present invention. Accordingly, descriptions will be regarded as illustrative in nature and not as restrictive in any form whatsoever. Modifications and variations of the system and apparatus described herein will be obvious to those skilled in the art. Such modifications and variations are intended to come within the scope of the appended claims.