Apparatus for applying surgical fasteners

Abstract: A surgical stapling or fastening instrument 10 for applying surgical fasteners to tissue having an adjustable closure mechanism to linearly approximate the distance between the jaw members of the instrument. The adjustable closure mechanism consists of an advancing means 26 and a retaining mechanism 44 which is actuable to urge the jaw members towards each other. A coupling arrangement 60 is also provided which permits firing of the staples or fasteners only when the jaw members are approximated a predetermined distance from each other.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to surgical instruments for applying surgical fasteners or staples to body tissue, and more particularly to an apparatus for applying surgical fasteners having adjustable mechanisms for controlling the spacing between the jaw members through which the tissue passes during the fastening or stapling procedures. 2. Discussion of the Related Art Surgical fastening devices having means for controlling the spacing between the jaw members are well known in the art. These devices typically include indicating means to provide a reading of the spacing between the jaw members. Devices are also known in the art which provide latching mechanisms to actuate the firing mechanism only when the distance between the jaws is within a preset range. These devices typically include a complex lock-out mechanism. Various closing mechanisms are provided in the prior art for use with surgical fastening devices. The most notable of these devices utilize a complex worm gear-type arrangement or screw bearing member to open and close the spacing between the jaw members of the surgical fastening apparatus. These devices generally provide a rotatable knob or wing-like assembly at the trigger end of the device remote from the jaw mechanism which carries the fastener cartridge, and a screw-like mechanism is provided that passes through the body of the device to translate the rotational movement of the knob into longitudinal movement of the cartridge frame to open and close the spacing between the jaws. As the jaw members are closed around a tissue site to which fasteners are to be applied, the surgeon must grasp the device with one hand while rotating the knob or wing-like assembly with the other hand. As the jaws members close about the tissue to pinch the tissue therebetween, the surgeon then ceases rotation and activates the trigger mechanism the drive the fasteners into the tissue. Several known devices provide a trigger-like mechanism, while others provide a secondary rotatable knob for driving the fasteners by rotational movement. Many devices provide an indicator means near the rotatable knob which gives a visual indication of the spacing between the jaw members prior to firing. These prior art devices are subject to several disadvantages in both use and construction which render these devices difficult to operate and expensive to manufacture. Many of the devices are cumbersome in use in that the surgeon must operate the device with both hands, holding the body of the instrument in one hand while rotating the knob or wing assembly with the other hand. This may lead to inaccurate stapling or fastening since the surgeon is unable to guide the tissue to be stapled or fastened with his free hand while closing the jaws about the tissue. Furthermore, the number of interacting components provides inaccuracies due to normal break down of tolerances. In addition, the gear arrangement may become worn during extended use, thus rendering an imprecise grasping action at the jaws. Furthermore, these prior art devices generally involve a complex construction in which a precisely machined or cast worm gear must be constructed and incorporated into the device. This of course increases the cost of manufacturing, and requires a sophisticated assembly procedure to properly locate the worm gear in the instrument to control the spacing between the jaws. Typical devices having a rotatable knob at the end portion adjacent the handle mechanism of the surgical stapling or fastening device are disclosed in, among others, U.S. Patent No. 4,930,503 to Pruitt, U.S. Patent No. 4,788,978 to Strekopytov et al., and U.S. Patent No. 4,606,344 to DiGiovanni. In each of these devices, an elongated rod member having screw threads machined thereon is provided, which connects a rotatable knob positioned adjacent the handle members to a pusher mechanism which urges a movable jaw in a forward direction toward a stationary jaw to close the spacing between the jaw members. When a desired spacing is reached, a trigger mechanism may be activated to fire the fasteners through the tissue into the anvil member mounted on the stationary jaw. To remove the fastening instrument after application of the fasteners, the knob is rotated in an opposite direction which turns the screw threaded rod member to move the movable jaw member away from the stationary jaw member so that the entire device maybe removed from the tissue. Surgical fastening instruments having a wing like arrangement positioned adjacent the handle assembly of a device for moving a movable jaw toward a stationary jaws for affixing surgical fasteners to tissue are disclosed in U.S. Patent No. 4,442,964 to Becht, U.S. Patent No. 4,354,628 to Green, and U.S. Patent No. 3,795,034 to Strekopytov et al. These devices are similar to those described above except for the provision of a rotatable wing member in place of the rotatable knob. These devices are also provided with a screw threaded rod member which, when rotated, urges a movable jaw towards a stationary jaw to close the jaw members around tissue to be fastened together. After the application of surgical fasteners, the wing assembly is rotated in an opposite direction to draw the movable jaw away from the stationary jaw so that the instrument maybe removed from the tissue. Surgical stapling of fastening instruments having a pivotable mechanism external to the device for moving a movable jaw toward a stationary jaw prior to affixing surgical fasteners to tissue are disclosed in, among others, U.S. Patent No. 3,269,630 to Fleischer, U.S. Patent No. 4,530,453 to Green, U.S. Patent No. 4,715,520 to Roehr, Jr. et al., and U.S. Patent No. 4,978,049 to Green. Green ('453), Roehr, Jr. et al. and Green ('049) each disclose a pivotable lever member which urges a movable jaw into proximity of a stationary jaw prior to application of the surgical fasteners. Fleischer discloses a surgical stapling instrument in which a pivotable handle urges the movable staple cartridge against the tissue in the direction of the stationary jaw and fires the staples in the same motion. In each of these devices, removal of the instrument after firing of the surgical fasteners is accomplished by pivoting the lever mechanism in the opposite direction to open the jaw members by moving the movable jaw away from the stationary jaw. EP-A-0479131 corresponds to U.S. Application Serial No. 593,697. It discloses a spring biased pivotal catch member for approximating the jaws which is held in selected positions by a pointed lance member. EP-A-0479131 was published April 8, 1992, a date between the present filing date and declared US priority date. It declares an earlier US priority date and so has to be considered relative to EPC Art. 54(3). The novel surgical stapling or surgical fastening device of the present invention is aimed at obviating the disadvantages encountered in the prior art and providing an efficient surgical fastening device having an adjustable closure mechanism for controlling the spacing between the jaw members of the surgical fastening apparatus. The device of the present invention aims to allow a surgeon to operate a surgical fastener with one hand while freeing the other hand to assist in the surgical procedure. Furthermore, the present invention aims to provide a novel means for coupling the fastener driving mechanism to the firing mechanism when the jaws are approximated to a preset distance. The device of the present invention is of lightweight construction and aims to offer ease of handling through the provision of a thumb controlled adjustable closure mechanism which permits a surgeon to set the spacing between the jaw members and fire the device while using only one hand. SUMMARY OF THE INVENTION The essential technical features of the present invention are recited below in claim 1. The present invention provides a surgical fastening device having a novel mechanism for adjusting the distance between the movable jaw and the stationary jaw prior to the application of fasteners to the body tissue. The adjustable mechanism controls the closing of the jaw mechanism to approximate the distance between the jaw members prior to activation of the trigger mechanism to fire the fasteners. The device of the present invention may be operated with one hand, which frees the surgeon to accurately locate the tissue to be repaired and to place the fasteners in the proper position during the procedure. The adjustable closure mechanism is operable by using the thumb of the hand which holds the device, and linearly moves the stapling mechanism to properly approximate the distance between the jaw members. The adjustable closure mechanism of the present invention eliminates many moving parts associated with prior devices, and provides a device which is lightweight, and easy to use by allowing the surgeon to set and release the device with one hand. The adjustable closure mechanism of the present invention may be used with any surgical instrument having jaw members which include a stationary jaw and a movable jaw, or two movable jaws, in which the spacing between the jaw members is adjustable to accommodate various thicknesses of tissue to be secured. The provision of the approximating actuator at the handle end of the instrument and the elimination of numerous complex moving parts which are common in prior art devices allows the surgeon to approximate the distance between the jaw members in a fast and efficient manner to position the jaws in the proper alignment for the application of surgical fasteners. The apparatus of the present invention comprises a first jaw member and a second jaw member in which the first jaw member includes a plurality of fastener means positioned in a cartridge which is movable with the first jaw member towards the stationary second jaw member. The second jaw member may include an anvil surface for clinching the fasteners, or may include means for engaging the fasteners to secured the tissue therebetween. Means for advancing the first jaw member towards the second jaw member to grip the tissue between the jaws are provided, as well as releasable means for retaining the advancing means along a linear path of travel to selectively position the first jaw member in relation to the second jaw member. Means for driving the fasteners into the tissue subsequent to positioning the jaw members in relation to each other by the advancement means is also provided, and the advancement means of the apparatus of the present invention is independent of the driving means. The present invention provides an adjustable closure mechanism for a surgical fastener applying apparatus in which the closure mechanism involves a two-step procedure to approximate the distance between the jaws to grip tissue therebetween. The two-step approximating process may be performed with one hand, since the two-step process is performed using the same mechanism. In a first embodiment of the present invention, a pusher bar mechanism comprising the advancing means is also provided; however, the pusher bar mechanism is pivotably actuable to provide for approximation of the jaw members over a large distance, and is also pivotably actuable to provide for incremental adjustment of the gap between the jaws following the initial approximation. In this embodiment, the pusher bar mechanism is not linearly slidable, but instead only pivots to provide for approximation of the distance between the jaw members. A pair of pawl members are provided on the pusher bar mechanism which engage a corresponding pair of ratchet members positioned on a movable rod which moves the cartridge frame and the fastener driver, which both cooperate with the movable cartridge jaw. In order to approximate the gap between the jaw members, the pusher bar mechanism is pivotably pushed in a downward, "pumping" motion so that the first advancing means advances the cartridge jaw a large distance. The first advancing means comprises a pawl member positioned on the pusher bar mechanism which engages a ratchet member positioned on the movable rod, where the ratchet member has relatively large spaced tooth portions to engage the pawl member. Pumping the pusher bar mechanism causes the ratchet and pawl mechanism to urge the movable rod forward so that the jaws move closer together. A retaining mechanism comprising a pivotable clamp member having a central bore through which the movable rod member passes is provided, so that the edges of the central bore frictionally engage the movable rod member to allow it to move forwardly to close the gap between the jaws, but not rearwardly until the clamp member is pivoted to release the rod member. Once the initial, greater distance is approximated by the first advancing means, the second advancing means, which comprises a second pawl member positioned on the pusher bar mechanism which engages a second ratchet means having smaller teeth than the first ratchet means, is activated to incrementally advance the cartridge jaw towards the anvil jaw. After the staples or fasteners are fired, the jaws may be returned to their initial position by pivoting the pusher bar mechanism upwardly to disengage the pawl members from the ratchet members, so that a spring, biased in the rearward or handle direction, returns the fastening apparatus to its at rest position. In a second embodiment, a pusher bar mechanism is provided at the distal end, or the handle end, of the surgical fastener applying apparatus. A ratchet and pawl mechanism is provided interiorly within the housing of the device, and is cooperatively engaged with the pusher bar mechanism. The pusher bar mechanism is linearly actuable so that the pusher bar mechanism may be pushed distally into the housing of the device by the thumb of the surgeon using the device. This initial distal thrust moves the cartridge jaw member towards the stationary anvil jaw member to substantially close the gap between the two jaw members to position and grip the tissue to be stapled or fastened therebetween. Once the initial push motion is completed, the pusher bar mechanism is pivotably actuated through a series of downwardly directed thrusts to "pump" the pusher bar mechanism. This pumping motion actuates the second advancing means which comprises the pawl mechanisms attached to the pusher bar mechanism, which engage a ratchet member fixedly positioned within the interior of the housing of the apparatus. The ratchet and pawl apparatus provides for incremental moving of the jaw assembly to provide a fine adjustment of the gap between the jaws. After firing the staples or fasteners into the tissue, the jaws may be returned to their rest position by pivoting the pusher bar mechanism upwardly to disengage the ratchet and pawl mechanism. A spring, biased in the proximal direction, returns the advancing means and the jaw mechanism to its original position. In a third embodiment of the present invention, a push rod mechanism is provided where the rod member extends from the distal end of the device through the housing and is connected to the fastener driver and cartridge frame through a universal joint. The pusher rod mechanism comprises the advancing means which includes a first linear advancing means and a second rotatable advancing means. The rod member passes through the central bore of a pivotable clamp member which engages and holds the rod member along its path of travel to provide for a controlled adjustment of the spacing between the cartridge jaw and the anvil jaw. The pusher rod mechanism is thumb actuable by a surgeon to advance the rod through the clamp member to linearly advance the cartridge jaw towards the anvil jaw. The rod member is provided with a screw-threaded portion which engages the clamp member after the initial approximation. The jaws may be further incrementally approximated by rotating the pusher rod mechanism to advance the rod through the screw threads which engage the clamp member. This provides for fine adjustment of the spacing between the jaws. After the fasteners are fired through the tissue, the mechanism may be released by pivoting the clamp member to release the screw threads and consequently the rod member to return the rod member to its original position. Preferably, a coupling mechanism is provided which couples the fastener driving means to the trigger mechanism to allow for driving of the staples or fasteners when the proper distance between the jaw members is set. As the approximating mechanism is actuated to move the cartridge frame, the cartridge and the fastener driving means forwardly, a coupling arm, which is connected at one end to the trigger mechanism, slides along a bearing surface on the driving means until the approximating mechanism is fully deployed. At this point, a camming edge of the coupling arm engages a notch in the bearing surface of the driving means to couple the trigger mechanism to the driving means. At this point, the proper distance between the jaw members is set and the fastener means may be driven into the tissue. After the fastening means have been driven into the tissue, the releasable retaining mechanism may be disengaged so that the jaw members may be returned to their original position whereby the fastening device may be removed from the surgical site. In a first embodiment, the push bar mechanism is pivoted to disengage the retaining means directly. In a second embodiment, the push bar mechanism is pivotable to move a second rod member which serves as a release lever to disengage the retaining means. In a third embodiment, a release knob is provided which extends through the housing of the fastening apparatus and which may be pivoted to release the retaining means. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing features of the present invention will become more readily apparent and may be understood by referring to the following detailed description of an illustrative embodiment of the surgical fastening instrument and its novel adjustable closure mechanism, taken in conjunction with the accompanying drawings, in which: Fig. 1 illustrates a perspective view of a first embodiment of surgical fastening instrument employing the adjustable closure mechanism of the present invention; Figure 2 illustrates a partial enlarged side cross sectional plan view of the handle end of a surgical instrument employing a first embodiment of the adjustable closure mechanism of the present invention in which the instrument is at an at rest condition; Figure 3 illustrates a partial enlarged side cross sectional plan view of the device of Figure 2 in which the adjustable closure mechanism of the present invention is fully deployed so that the device is in the fully loaded condition; Figure 4 illustrates a partial enlarged side cross sectional plan view of the handle end of the surgical instrument of Figure 2 in which the release mechanism has been activated to disengage the retaining means and the adjustable closure mechanism; Figures 5a and 5b illustrate a side plan view and a top plan view, respectively, of the pusher bar mechanism of the adjustable closure mechanism of Figure 2; Figures 6 to 11 inclusive are cancelled; Figure 12 illustrates a perspective view of a second embodiment of surgical fastening instrument employing a second embodiment of the adjustable closure mechanism of the present invention; Figure 13 illustrates a partial enlarged side cross sectional plan view of the handle end of the surgical fastening instrument of Figure 12 employing the second embodiment of the adjustable closure mechanism of the present invention in which the instrument is in an at rest condition; Figure 14 illustrates a partial enlarged side cross sectional plan view of the handle end of the surgical fastening instrument in which the adjustable closure mechanism of the present invention is fully deployed so that the device is in the fully loaded condition; Figures 15a through 15c illustrate the coupling mechanism according to the present invention for coupling the trigger mechanism to the fastener driving mechanism used in conjunction with the adjustable closure mechanism of the present invention; Figures 16a and 16b illustrate a side plan view and a front plan view, respectively, of a first embodiment of the retaining means of the adjustable closure mechanism of the present invention; and Figures 17a and 17b illustrate a side plan view and a front perspective view, respectively, of a second embodiment of the retaining means of the adjustable closure mechanism of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in specific detail to the drawings, in which like reference numerals identify similar or identical elements throughout the several views, Figure 1 shows a surgical fastening instrument 10 which employs the adjustable closure mechanism of the present invention. Fastening instrument 10 is provided with a stationary handle 12 and an actuating handle 14 which together comprise the trigger mechanism of instrument 10. An elongated body portion 16 is provided which terminates in a distal jaw mechanism 18 which includes an anvil jaw 20 and a cartridge jaw 22. A fastening cartridge (not shown) is positioned within cartridge jaw 22 for driving staples or fasteners through tissue against an anvil surface or into fastener retainers positioned on anvil jaw 20. At the handle end of instrument 10 is provided advancing mechanism 26 for advancing the approximating mechanism disposed within body portion 16 whose function will be described below. As seen in Figure 2, the adjustable closure mechanism according to a first embodiment of the present invention is shown. Pusher bar mechanism 28 is pivotably secured to the instrument at pivot point 36, and includes advancing means for adjusting or approximating the spacing between cartridge jaw 22 and anvil jaw 20. A first advancing means comprises the combination of first advancing pawl 30 which engages first advancing ratchet 40 which is secured to removable rod member 38. The second advancing means comprises a second advancing pawl 32 which engages a second advancing ratchet 42, where pawl 32 is also disposed on movable rod 38. Pusher bar mechanism 28 is shown in detail in Figures 5a and 5b, and it can be seen that pawl members 30 and 32 are spring biased through the provision of spring members 29 and 33, respectively. Spring member 29 biases pawl member 30 by abutting against post member 31 as shown; spring member 33 biases pawl member 32 by abutting its respective post member 31. A release block 34 is provided on advancing mechanism 28, whose function will be discussed below. Movable rod member 38 passes through a retaining mechanism 44, and is secured to fastener driver 62 and cartridge frame 64 to advance these elements in a distal direction to approximate the distance between cartridge jaw 22 and anvil jaw 20. Retaining mechanism 44 is shown in detail in Figures 16a and 16b, as well as Figures 17a and 17b. Retaining mechanism 44 is biased into the engaged position by spring member 54, and may be moved to a disengaged position by release rod 56 which is slidably mounted in support blocks 58. Ratchet 40 and pawl member 30 comprise the first advancing means which approximates the distance between the jaw members an initial distance. The second advancing means comprises ratchet 42 and pawl member 32 which advance the jaw members a second distance subsequent to approximation by the first advancing means. As can be seen in the drawings, the teeth of ratchet 40 are much larger than the teeth of ratchet 42, and thus provide for greater movement of the jaws than the smaller teeth of ratchet 42. Retaining mechanism 44 comprises a clamp member 46 which is pivotably mounted on a carriage member 50 and is biased into the engaged position by biasing spring 54. As best seen in Figure 16a and 16b, a block member 48 is provided having a shoulder portion 52 which provides a pivot point for clamp member 46. Clamp member 46 may include a spring post 47 as shown which engages biasing spring 54. Clamp member 46 further includes a central bore 70 through which movable rod 38 passes. In alignment with central bore 70 is a central bore 72 of block member 48 through which movable rod 38 also passes. A release bore 74 is also provided in block member 48 to allow release rod 56 to pass through and contact the upper portion of clamp member 46. Figures 17a and 17b illustrate an alternate embodiment of retaining mechanism 44. The embodiment of Figure 17a is identical to the embodiment of 16a except for the provision of a leaf spring 55 which provides the biasing force on clamp member 46 instead of biasing spring 54. The operation of the adjustable closure mechanism of Figure 2 will now be described. After the tissue to which the surgical fasteners are to be applied is positioned between cartridge jaw 22 and anvil jaw 20, cartridge jaw 22 is advanced distally to grip the tissue therebetween by activating advancement means 26. Pusher bar mechanism 28 is pivotably actuated by pumping pusher bar mechanism 28 repeatedly in the direction of arrow A. This motion causes pawl member 30 to engage ratchet 40 to urge movable rod 38 in the direction of arrow B. Movable rod 38 is prevented from moving rearwardly by retaining mechanism 44. As pusher bar mechanism 28 is pumped in the direction of arrow A, pawl member 30 engages successive teeth of ratchet 40 to move rod member 38 forwardly. Moving movable rod 38 forwardly causes fastener driver 62 and cartridge frame 64 to move forwardly as cartridge jaw 22 moves towards anvil jaw 20 to grip the tissue therebetween. When pawl member 30 is engaged in the last tooth of ratchet 40 at the proximal end of ratchet 40, pawl member 32 engages the first tooth at the distal end of ratchet 42. Ratchet 42 and pawl member 32 provide for incremental adjustment of the distance between cartridge jaw 22 and anvil jaw 20 and moves movable rod 38 over small distances compared to the distance traversed through the cooperation between pawl member 30 and ratchet means 40. As movable rod 38 urges fastener driver 62 and cartridge frame 64 forwardly, coupling arm 60, as best seen in Figures 15a through 15c, slides along bearing surface 66 of fastener driver 62 until the jaws are approximated at the desired distance, when coupling arm 60 is engaged in notch 68 to permit driving of the fasteners into the tissue. This position is clearly seen in Figure 3. At this point, actuating handle 14 may be moved towards stationary handle 12 to fire the fasteners into the tissue. After the fasteners are driven into the tissue, the adjustable closing mechanism, and the cartridge jaw, may be returned to the position shown in Figure 2 by releasing the retaining mechanism 44. As best seen in Figure 4, this is accomplished by pivoting the pusher bar mechanism 28 in the direction of arrow C so that release block 34 is moved in the direction of the arrow C_. Release block 34 engages the rear end of release rod 56 which urges release rod 56 forwardly through support blocks 58 and against the upper portion of clamp member 46. Clamp member 46 is moved in the direction of arrow D to disengage the edges of central bore 70 from movable rod 38. Release block 34 also lifts support blocks 58 to lift ratchet mechanisms 40 and 42 away from pawl members 30 and 32, respectively, to allow movable rod 38 to move rearwardly in the direction of arrow E to return the instrument to the at rest position shown in Figure 2. As the distance between the jaw members is set to a desired distance, driving pin 106 moves to the distal end of frame track 108 so that drive link 102 assumes a substantially vertical position. This draws alignment pin advancing means 24 slightly rearwardly so that alignment pin 116 engages the hole in anvil jaw 20 but does not extend beyond the jaw as shown. The cartridge frame advancing means, cartridge jaw 22, and carriage are now in a position for firing. At this point, due to the movement of driving pin 106, fastener driver 62 has moved into position to fire the fasteners into the tissue. This can be seen by the engagement of coupling arm 60 in notch 68 of fastener driver 62. Coupling arm 60 has slid off bearing surface 66 and into notch 68 so that the fasteners may be fired. Fasteners are driven into the tissue by moving actuating handle 14 Coupling arm 60 moves fastener driver 62 forwardly to drive the fasteners into the tissue. After firing, actuating handle 14 is returned to its at rest position by biasing spring 110. Figures 12 through 14 illustrate a surgical fastening apparatus 130 employing a further embodiment of the adjustable closure mechanism of the present invention. Device 130 includes actuating handle 14, stationary handle 12, and body portion 16 which terminates in a jaw mechanism 18 similar to that described above. Jaw mechanism 18 includes an anvil jaw 20, a movable cartridge jaw 22, and an alignment pin advancement means 24 similar to that described above. Instrument 130 further includes a first advancing means 132 and a release bar 134 for releasing a retaining mechanism which will be described below. Turning now to Figures 13 and 14, there is illustrated the retaining mechanism 44 which is similar to that described above. Retaining mechanism 44 includes a clamp member 46 to which release bar 134 is attached. Retaining mechanism 44 further includes block member 48 having shoulder 52, all of which are mounted to carriage 50 as described above and best shown in Figures 16a and 16b and 17a and 17b. First advancing means 132 comprises a pusher knob 136 for advancing an advancing rod 138 into the housing of instrument 130. In use, pusher knob 136 is urged forwardly in the direction of arrow K to move advancing rod 138 forwardly. Advancing rod 138 further includes second advancement means 140, which comprises screw threads 141, whose function will be described below. Advancing rod 138 and screw threads 141 pass through central bore 70 of clamp member 46 and central bore 72 of block member 48 and terminate in universal joint 142 which is attached to cartridge frame 144 and fastener driver 62 whose functions are identical to that described above. Turning now to Figure 14, advancing rod 138 is moved forwardly until clamp member 46 engages screw threads 141. At this point, cartridge jaw 22 has been approximated a great distance towards anvil jaw 20 to grip tissue therebetween. Pusher knob 136 may then be rotated by the thumb of the surgeon in the direction of arrow L to further advance cartridge jaw 22 towards anvil jaw 20, since the rotational motion is for fine adjustment of the spacing over a small distance. Rotation of pusher knob 136 allows advancing rod 138 to further move forwardly through the cooperation of screw threads 141 with central bore 70 of clamp member 46. The rotational movement of rod 138 is translated into longitudinal movement through the provision of universal joint 142. After the jaws have been approximated to a desired distance, coupling arm 60 engages notch 68 of fastener driver 62 and actuating handle 14 may be moved towards stationary handle 12 to fire the fasteners into the tissue. The following firing of the fasteners, the entire mechanism may be released and returned to its at rest position by moving release bar 134 in the direction of arrow M to disengage screw threads 141 from central bore 70. Release bar 134 moves in the direction of arrow M against biasing spring 146 which maintains engagement of central bore 70 with rod member 138. The adjustable closure mechanism of the present invention can also be used in other instruments to close the distance between the movable jaw member and the stationary jaw member at the stapling or fastening end of the instrument or between two movable jaw members. That is, the jaw mechanism may be of the type wherein one jaw moves toward and away from the other; however, the present invention is also applicable for use with devices of alternative types, i.e., where both jaws move toward and away from each other. The surgical instrument may be of the type which applies metal staples or two-part fasteners of the bioabsorbable type. The surgical stapling or fastening instrument employing the adjustable closure mechanism of the present invention is a device which may be operated with one hand to effect the closure motion of the jaw members of the instrument followed by activation of the trigger mechanism to fire the staples or fasteners into the tissue. The complex rotational or pivoting arrangement of the prior devices is eliminated, resulting in a lightweight and easy to handle instrument which is inexpensive to manufacture and easy to assemble. Within their scope, the claims below define further embodiments of the invention.

Claims: Apparatus (10) for applying surgical fasteners to body tissue, comprising: tissue gripping means (18) for positioning and gripping tissue to which said fasteners are to be applied; said gripping means including a first jaw member (22) having a plurality of fasteners positioned thereon, and a second jaw member (20); first advancing means (30, 38, 40) for urging said first jaw member a first distance towards said second jaw member; second advancing means (32) for incrementally urging said first jaw member a second distance towards said second jaw member subsequent to urging by said first advancing means to grip tissue therebetween, the said second distance being less than the first distance, the adjustable spacing between the jaw members serving to accommodate a particular thickness of tissue to be secured; means (62) for driving said fasteners into said tissue subsequent to positioning said jaw members in relation to each other by said advancing means; means (14) for actuating said driving means; and releasable means (44) for retaining said first and second advancing means to selectively position said first jaw member in relation to said second jaw member. Apparatus according to claim 1, wherein said retaining means comprises a pivotable clamp member (469) having a central bore (70) through which said first advancing means passes, an edge of said central bore engaging said advancing means to retain said first advancing means (38) and selectively position said first jaw member in relation to said second jaw member. Apparatus according to either of the preceding claims, further comprising release means (34, 56) associated with said retaining means for disengaging said retaining means from said advancing means to return said advancing means to a rest position. Apparatus according to any one of the preceding claims further comprising means (60) for coupling said driving means to said actuating means, said driving means driving said fasteners only when said first jaw member is approximated a predetermined distance towards said second jaw member. Apparatus according to claim 4, wherein said coupling means comprises a bearing surface (68) on said driving means (62) for engaging an arm member (60) of said actuating means for driving said fasteners only when said first jaw member is approximated to said predetermined distance towards said second jaw member. Apparatus according to claim 5, said bearing surface comprising a notch (68) for engaging said arm member, said notch extending from a sliding surface on said driving means upon which said arm member rides prior to engaging said notch. Apparatus according to any one of the preceding claims wherein said first and second advancing means are coupled to said driving means to advance said driving means into a firing position. Apparatus according to any one of the preceding claims wherein said first advancing means (30, 40) advances said first jaw member towards said second jaw member through a pivoting movement of a pawl (30). Apparatus according to any one of the preceding claims wherein said first and second advancing means comprises a first ratchet and pawl mechanism (30,,40) and a second ratchet and pawl mechanism (32, 42) and said retaining means comprises said second ratchet and pawl mechanism (32, 42). Apparatus according to any one of the preceding claims wherein the first advancing means is reciprocatingly pivotable. Apparatus according claim 10 wherein said advancing means comprises a pivoting bar mechanism (28) extending from a housing of said apparatus and adapted to be reciprocatingly pivoted in a first direction in relation to a longitudinal axis of said apparatus to advance said first jaw member towards said second jaw member, said bar mechanism being biased to return to a rest position in substantial alignment with said longitudinal axis, said reciprocating pivoting of said bar mechanism downwardly deflecting said bar mechanism from said longitudinal axis. Apparatus according to claim 11, wherein said pivoting bar mechanism comprises at least one ratchet (32, 42) and pawl (30, 40) mechanism for incrementally advancing said first jaw member towards said second jaw member. Apparatus according to claim 11 or 12 as dependent on claim 3 wherein said release means comprises a release rod (56), said release rod contacting said retaining means (44) to disengage said retaining means upon pivoting said pivoting bar mechanism in a second direction opposite said first direction. Apparatus according to any of the preceding claims wherein said advancing means comprises a rod member (28, 132) extending distally from a housing of said apparatus and being thumb actuable by an operator to advance said first jaw member. Apparatus as claimed in any one of the preceding claims, said advancing means including linearly actuable advancing means (138) for urging said first jaw member towards said second jaw member a predetermined distance and rotatable advancing means (141) for urging said first jaw member towards second jaw member to grip said tissue therebetween. Apparatus according to claim 15, wherein said linearly actuable advancing means urges said first jaw member towards said second jaw member by said first predetermined distance, and said rotatable advancing means incrementally urges said first jaw member towards said second jaw member subsequent to urging by said linearly actuable advancing means. Apparatus according to claim 15 or 16 wherein said linearly actuable advancing means comprises a rod member (138) extending distally from a housing of said apparatus and being thumb-actuable by an operator to advance said first jaw member and said rotatable advancing means comprises screw threads (141) integral to said rod member, said screw threads engaging said retaining means for incrementally advancing said first jaw member in relation to said second jaw member.

Inventors: BOLANOS HENRY, GREEN DAVID T, HEATON LISA W, RATCLIFF KEITH, VIOLA FRANK J, BOLANOS, HENRY, GREEN, DAVID T., HEATON, LISA W., RATCLIFF, KEITH, VIOLA, FRANK J.
Applicants: UNITED STATES SURGICAL CORP, UNITED STATES SURGICAL CORPORATION
Application year: 1992
Main classification: A61B17
IPC codes: A61B17