Abstract:
A tacker instrument for laparoscopic applications fits within a cannula and incorporates within a sleeve a positioning and driving system coupled to a tack holder mechanism at the distal end. The tack is held unexposed during entry but then may be extended to a predetermined position for embedment, with position being verifiable through the sleeve. Impact forces for embedding or removing the tack are applied to the positioning and driving mechanism, and the tack and tack holder are configured so that there is lateral disengagement or engagement of the two. In one version the mechanism is linear, while in a second version the distal end of the sleeve device can be angulated for perpendicular tack entry or removal with impelling forces being applied through a flexible shaft segment.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to devices and methods for laparoscopic surgery, and more particularly to devices and methods for inserting and removing tacks during laparoscopic surgery. 
     Laparoscopic surgery, or the effecting of surgical procedures in body cavities through body walls, became feasible with the development of small cross-section viewing and manipulating instruments, and has since been the procedure of choice for a number of particular operative situations. Consequently, there have been developed a significant number of devices that can be inserted into a body cavity for moving, cutting, fastening and cauterizing, among other functions, so that laparoscopic procedures can be carried out quickly, with low trauma and thus with minimal discomfort and recovery time. 
     A number of different surgical procedures have been developed or are contemplated for use, for example, in the abdominal cavity. Abdominal rectopexy, involving such conditions as a prolapsed uterus, prolapsed vagina or prolapsed rectum, has been treated using this approach. The abdominal cavity affords not only sufficient volume in which to conduct necessary surgical procedures, while visualizing the site through a camera port or using an endoscope, but also includes usable anchor structures, such as cartilage of the sacrum. Experimental procedures have shown that prolapsed tissue can be manipulated to, and then anchored in, a given position, using a mesh of sterile, inert filaments. For this purpose, however, a laparoscopic tacking instrument is needed that will meet the size and shape constraints imposed on any laparoscopic device. The instrument should further maintain a tack in unexposed position during insertion, provide a seating surface that does not slip when the tack is being driven in, allow verification of the tack position, retain the tack securely so that it cannot become loose within the body cavity, and permit application of the necessary forces for driving the tack into and out of position. Both embedment and disengagement of the tack should be feasible with the same instrument. 
     SUMMARY OF THE INVENTION 
     A laparoscopic tacking instrument and method in accordance with the invention incorporates a sleeve that is sufficiently thin to fit within a cannula and long enough to extend proximate to a tacking site inside a body cavity at its distal end. The instrument includes an exterior portion accessible to a surgeon, together with a driving and positioning shaft extending through the sleeve and having a tack holding device mounted in its distal end. Also, in the exterior portion, a positioner is incorporated that is configured to enable control of both axial and circumferential positions of the shaft and the tack relative to the sleeve. 
     The positioner may include a shaped continuous guide slot in a positioning sleeve attached to the proximal and of the sleeve body, and an interior positioning pin coupled to the shaft rod. This arrangement facilitates entry of the sleeve into the body cavity with the tack securely held in the tack holder but not exposed. Thereafter, the sleeve and tack may be placed in position at a given region and driven in to the sacrum until fully seated. The tack holder may then be slid sideways from the tack to complete the procedure. A tack, once embedded, may be removed by a reverse procedure. 
     Among the features employed with this system are a viewing window in the sleeve through which the position of the tack positioning mechanism and therefore the tack, may be verified. Also, a slidable weight may be attached to the proximal end of the positioning and driving shaft to provide adequate impact force without vigorous motion. 
     In a specific example of the laparoscopic instrument, the cylindrical sleeve is arranged for direct insertion through a cannula or port. Spaced apart from the distal end of the sleeve is a viewing guide slot, with indicia which enable the operator to see (&#34;visualize&#34;) the drive mechanism and its position relative to the sleeve. The tack holder comprises a pair of laterally extending arms which fit a groove between two spaced apart heads in the tack, the arms being biased under spring pressure toward the distal end of the drive mechanism, so that the tack is held firmly in position but can nonetheless be released when it should be disengaged. A control knob on the drive mechanism exterior to the body wall is accessible to the surgeon for controlling sleeve and tack position. A weighted mass or impeller is attachable to the outer end of the drive mechanism, and is freely reciprocable over a short distance so that the mass of the impeller enables the tack to be driven into or out of position with a series of controllable impacts requiring little strength or exertion. 
     In accordance with a different feature of the invention, the sleeve and internal drive rod mechanism are arranged to enable the distal end of the instrument to be pivoted through a limited angle, while still providing the positioning, driving and disengagement functions. This arrangement facilitates entering the tack into, or removing the tack from, the sacrum in a perpendicular direction where the attitude of the sacrum relative to the point of eating through the body wall is somewhat off line. In a specific example, the sleeve mechanism has a rotatable principal body about an interior fixed tube which supports an end tube segment encompassing the tack holder and tack during insertion. The end tube segment is pivotable about its proximal end on the interior fixed tube as the principal body of the sleeve mechanism is turned. A drive and positioning mechanism extends through the pivoting means and includes a flexible shaft portion of sufficient axial rigidity to transfer impact forces without buckling to the tack holder as the impeller is used. Means are provided for selecting the tack position, and visualizing it as well, through a viewing window in the end tube segment. 
     Other aspects of the invention facilitate use of systems and method in accordance with the invention for special purposes or functions. The tack itself advantageously has a double head in which the uppermost or proximal head is of smaller diameter than the other of the pair. Further, the upper head may include two or more diametrally opposed peripheral notches, such that a suture filament can be wrapped around the groove between the two heads and brought out through the notches. Thus, the tack itself can be used as a post when manipulating organs or elements, or as an anchor for tying off sutures. Another aspect is that the tack holding part of the instrument can be configured, together with the distal end of the driving and positioning mechanism, as a replaceable cartridge. For embedment of more than one tack, or a change of tack size, valuable time can be saved by rapid interchange of pre-loaded cartridges. 
     Another variation within the scope of the invention lies in the employment of pneumatic devices. For example, a pneumatic impulser may be attached to the proximal end of the positioning and driving mechanism. The pneumatic impulser is sufficiently small and light to be left in position during initial steps of a procedure, and can be remotely controlled as by a foot pedal. Such a mechanism can substantially shorten the time needed for tack embedment or removal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the invention may be had by reference to the following drawings, taken in conjunction with the accompanying description, in which like reference numbers refer to like parts and in which: 
     FIG. 1 is a generalized representation of an operative scene during a laparoscopic procedure using a laparoscopic instrument in accordance with the invention; 
     FIG. 2 is a combined sectional and perspective view of an operative site, during a laparoscopic procedure in accordance with the invention; 
     FIG. 3 is a side view in partially exploded form of a laparoscopic instrument in accordance with the invention. 
     FIG. 4 is a side view of a positioning and driving mechanism used in the instrument of FIG. 3; 
     FIG. 5 is a perspective view, partially broken away of the instrument FIG. 3; 
     FIG. 6 is a fragmentary side view of a tack holder mechanism and tack, showing alternate positions, A and B, before and after embedment of a tack; 
     FIG. 7 is a perspective view of an alternate instrument in accordance with the invention, in which the distal end may be angulated for perpendicularity to a target surface; 
     FIG. 8 is an enlarged perspective view, partially broken away, of the instrument of FIG. 7; 
     FIG. 9 is a side sectional view of the instrument of FIGS. 7 and 8, showing the angulation mechanism; 
     FIG. 10 is a fragmentary perspective view of a pivoting mechanism used in FIG. 9, showing further details thereof; 
     FIG. 11 is a simplified side view of a cartridge-type tack holder mechanism; 
     FIG. 12 is a top sectional view of the mechanism of FIG. 11; 
     FIG. 13 is a perspective view of a tack with peripheral notches used for anchoring a suture filament; 
     FIG. 14 is a top view of the tack of FIG. 13; 
     FIG. 15 is a schematic view of a control system for a pneumatic impeller, as shown in FIG. 7; and 
     FIG. 16 is a side sectional view of a pneumatic impeller device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIGS. 1 and 2, there is seen a generalized depiction of instruments and methodologies used in a typical laparoscopic procedure. After employing conventional insertion and insufflation procedures, a number of instruments have been positioned within a body cavity through the body wall 10. Illustrated are typical endoscope 12, a manipulator clamp 14, a viewer (seen in FIG. 1 only) and a laparoscopic instrument 20 in accordance with the invention. The surgeon is manipulating the laparoscopic instrument 20 at the same time he is observing the cavity interior through the viewer. A second surgeon manipulates the clamp 14, while viewing the image that is generated by the endoscope 12 on a separate video screen (not shown). In this particular procedure, the objective is to secure a prolapsed organ by attaching a synthetic biocompatible mesh 22 to interior cartilage, in this instance, the sacrum, using a surgical tack 24 as described in greater detail hereafter. The mesh 22 may be any of a number of materials approved for use in sterile, inert products for surgical applications. Laparoscopic operative procedures are based upon the fact that trauma to tissue is minimized while the interior of the cavity can visualized as fully as necessary utilizing the optical aids. Consequently all devices and instruments must have a small cross-sectional area at the body wall and within the body cavity. In the example of attachment of a prolapsed organ, the organ itself is secured to this biocompatible mesh 22 by staples or sutures (not shown). 
     In this example the laparoscopic instrument 20, referring now to FIGS. 1 to 6, is inserted through a cannula 25 extended into the body cavity after insufflation. An insufflation port 26 on the endoscope 12, or used at some other point where the pneumoperitoneum needle was previously used, is fed by a fluid pressure line 28, which typically injects air to prevent desufflation of the body cavity through leakage, so that internal organs remain readily accessible. The principal length of the instrument 20 itself is a cylindrical sleeve 32 which fits through the cannula 25 in sliding relation and which can be extended into proximity with the tacking site. As seen particularly in FIG. 5, the sleeve 32 includes a larger diameter positioning sleeve 34 at its proximal end, exterior to the body wall 10. The positioning sleeve 34 includes a position control slot 36 having axial and circumferential segments relative to the central axis of the instrument 20. Different positions along the position control slot 36 determine, as is described below, where a tack 24 held at the other end of the instrument 20 is located relative to the distal end of the sleeve 32. The terminal edge 38 at the distal end of the sleeve 32 has a periodic or serrated circumferential pattern, in this case, a generally sinusoidal variation, to provide better seating against a sacral area which it contacts. 
     A long positioning and driving shaft 40 is disposed along the central axis of the sleeve 32, and extends to a tack retaining or holder mechanism 42 (see FIGS. 3 and 4 in particular) at the distal end. At its proximal end, the shaft 40 includes a positioning cylinder 44, best seen in FIG. 4, and extends outwardly through a positioning knob 46 to a threaded end 50. The positioning cylinder 44 is movable within the positioning sleeve 34 and includes a radially extending pin 52 that fits within the positioning slot 36, as best seen in FIG. 5. 
     In the tack holder mechanism 42, a pair of arms 53, 54 extend in opposite senses within a lateral plane normal to the central axis from an extension 56, to fit between spaced apart upper and lower heads 58, 59 on the surgical tack 24, which is typically of titanium. Serrations 60 along the shaft of the tack aid in retention of the tack 24, once embedded, but the force of retention may be overcome if it is desired to remove the tack 24. The extension 56 has a body diameter for a sliding fit within the sleeve 32 and the arms 53, 54 can also be withdrawn within the sleeve 32. Spaced apart from the arms 53, 54 on the tack holder mechanism 42 is a length of round tubing 62 fixed to the shaft 40, and providing a reference shoulder for a compression spring 63 which exerts a mechanical bias on the extension 56 and on a tack 24 retained between the arms 53, 54 to permit the tack to remain in position during withdrawal movements of the drive mechanism shaft 40 within the extension 56. The shoulders at the ends of the length of tubing 62 are positioned so that they align with the transverse arms 65 on a cruciform indicator window 64 in the sleeve 32, for different modes of operation. When the tack is fully retracted within the distal end of the sleeve 32, the distal end of the tubing segment 62 is aligned with the transverse arms 65 of the indicator window 64. However, when the proximal end of the tubing segment 62 is in alignment with the transverse arms 65, the tack 24 fully extends from the terminal edge 38 of the sleeve 32. A similar indicator window 64 may be disposed on the opposite side of the sleeve 32 if desired. Use of an indicator window for positive identification of tack position provides an added degree of assurance inasmuch as the tack 24 itself may be partially or wholly obscured by tissue. 
     At the proximal end of the shaft mechanism 40, the threaded portion 50 is detachably securable to a threaded slider 66 that is reciprocable over a short distance within a cylindrical weight 68, the slider 66 having a matching female thread to the male threaded end 50 of the shaft. By this means, the weight 68 when attached at the interior slider 66 may be accelerated freely through a short distance before impacting the proximal end of the shaft 40. This provides a smooth but forceful tapping action to embed the tack 24 in position, or alternatively to withdraw a secured tack that was previously embedded. 
     The operation of the instrument 20 shown in FIGS. 1 to 6 will be described independently of the surgical procedure that is used, although examples of abdominal rectopexy and prolapsed uterus provide typical illustrations of where the procedure is of greatest benefit. Briefly, the biocompatible mesh 22 is first inserted into the cavity in a tightly rolled condition, then unrolled, positioned, and tacked to the sacrum using the surgical tack 24, after which it is sutured or stapled to the organ to maintain the organ in position. For embedment of the tack 24, the instrument 20 is preferably introduced into the abdomen through a cannula 25 that is perpendicularly aligned with the sacral region at which embedment is to take place. During insertion, the tack 24 is fully withdrawn into the distal end 38 of the sleeve 32, by shifting the positioning pin 52 to the first position A (FIG. 5) in the positioning slot 36 using the knob 46. The serrated terminal edge 38 is engaged against the sacrum at the point of embedment and the shaft mechanism 40 is rotated until the pin 52 is in longitudinal alignment with the position B. The weight 66 is then attached to the proximal end of the shaft 40 and the shaft 40 is driven in by repeated tapping motions, until the point B is reached on the position slot 36. This corresponds to the full insertion position in FIG. 6. The position of full embedment of the tack 24 may be verified by a reference to the location of the proximal end of the tubing segment 62 to the transverse arms 65 within the window 64. To separate the tack 24 from the holder 42, the positioning pin 52 is moved to the position C, which moves the sleeve 32 back until the tack 24 is clear of the terminal edge 38. In this position also the arms 53, 54 are opposite the viewing window 64, so that a limited lateral movement of the distal end of the instrument 20 frees the arms 53, 54 from the space between the heads 58, 59 as depicted in FIG. 5. To remove a tack 24, the arms 53, 54 are inserted sideways between the double heads 58, 59 of the tack 24, and the weight 68 is impacted outwardly until separation of the tack is complete. 
     It will sometimes happen that the location of a tacking position within the body cavity is such, relative to the axis of entry of a cannula, that a tack cannot be embedded or extracted in a direction perpendicular to the surface of the sacrum. If the long axis of a tack that is interior to the body cavity can be shifted through an arc, however, this can remove the necessity for a separate penetration of the cavity wall with a cannula or trocar, and saves valuable time as well. The version of a laparoscopic tacker in accordance with the invention shown in FIGS. 7 to 10 accomplishes this result. In these Figures, the cannula 25 is not shown for purposes of more clearly seeing the device itself. 
     In the angulated laparoscopic tacker 70 FIGS. (7 to 10), a longitudinal cylinder body 72 is dimensioned to slide within a cannula (not shown), the cylinder body 72 being attached at its proximal end to a control ring 74 by which it may be rotated about its central axis. The peripheral edge of the distal end of the cylinder body 72 is configured to define a circumferential cam surface 75. The cam surface 75 is used in turning a pivotable end cylinder 80, which is nominally collinear with the cylinder body 72, and which has the same diameter, so that the end cylinder 80 defines an angulated tip or extension portion of the body 72. Within the cylinder body 72, an inner, concentric cylinder 82 is substantially co-extensive with the cylinder body 72 along the length of its central axis. At its proximal end the inner cylinder 82 is coupled to a fixed, hollow handle 84 for use by the surgeon in manipulating the device. At the distal end, along a plane transverse to the central axis of the cylinder body 72, as best seen in FIGS. 9 and 10, the inner cylinder 82 has a pair of depending bearing members 86 supporting a transverse pivot shaft 88 that defines a pivot axis for the end cylinder 80. A bore 90 in the pivot shaft 88 has two parallel sides and two converging sides (diverging in the proximal to distal direction) in separate quadrants about the central axis, for purposes described hereafter. The end cylinder 80 is suspended from the inner cylinder 82 by bearings 91, attached to the end cylinder 80 on each side of the pivot shaft 88. The bearings 91 are large enough to allow rotation of the end cylinder 80 about the pivot shaft 88 with a sliding fit. As described above in the example of FIGS. 1-6, the distal end of the end cylinder 80 has a terminal edge 92 of varying or serrated circumferential shape, so as to provide better engagement against a sacrum or other surface in which a tack is to be placed. 
     A central drive and positioning shaft mechanism 100 extends from the handle 84 down to the distal end of the end cylinder 82. Within the handle 84, the shaft mechanism 100 includes a transverse arm 102 that extends through a positioning slot 104 in the handle 84, which positioning slot 104 may have axial and circumferential segments defining successive operating positions as in the example in FIGS. 1-6. The shaft mechanism 100 extends down through the central axis of the inner cylinder 82, and through the bore 90 in the pivot shaft 88. A length 105 of the shaft mechanism, however, is a flexible shaft, such as a helically wound element which has sufficient rigidity along its length to permit driving force in either direction without buckling, even though it may be bent through a limited angle relative to the central axis. A tack holder body 106, slidable within the inner wall of the end cylinder 80, is engaged to the distal end of the shaft mechanism 100, and retains a tack holder device 108, having tack receiving arms, 109,110 as previously discussed. An elastomeric plug 111, between the tack holder body 106 and the tack 24, engages the top of the tack 24 to maintain it in positively secured position within the arms 109, 110. At the proximal end of the handle 84, the end of the shaft mechanism protrudes through to a threaded end 112 to which a pneumatic impeller 114 can be attached as desired. 
     Details of the pivot mechanism are best seen in FIG. 9, to which reference is now made. The cam surface 75 on the cylinder body 72 has a cam riser portion 75a circumferentially midway between the points of intersection of the pivot axis with the approximate end of the cylinder body 72. The proximal end of the end cylinder 80 similarly has a circumferential cam follower surface 122, so when the cam riser portion 75a engages a higher surface on the cam follower 122 on the end cylinder 80, during rotation of the cylinder body 72, the end cylinder 80 is pivoted or angulated through an angle. The flexible segment 105 of the shaft mechanism 100 curves within the mechanism, principally on the side within the end cylinder 80, accommodating the relative motion. The diverging surfaces on the bore 90 allow this bending to take place within adequate limits. 
     The drive and positioning mechanism 100 can be reciprocated along its longitudinal axis, as by the use of a weighted mass or impeller 60 as described in conjunction with FIGS. 1-6. In this example, however a pneumatic impeller 114 as described below in conjunction with FIGS. 15 and 16 is attached and may be used in place of a positioning control knob. Different positions of the tack 24 relative to the terminal edge 92 of the end cylinder 80 can be set using the arm 102 in the handle 84 as previously described. The tack 24 thus can be held non-protruding concealed during entry, and extended in desired fashion beyond the distal end of the end cylinder 80 for embedment. Alternatively, the tack 24 may be removed by the reverse procedure. The end cylinder 80 includes, as in the prior example, a cruciform window 124 on one or both sides for visually verifying the tack position. 
     In the operation of this system of FIGS. 7 to 10, insertion is done as previously, with the tack 24 being concealed and protected within the end cylinder 80 as the cylinder body 72 is entered in the cannula (not shown). Thereafter, however, the proper angle of attack for entry of the tack 24 can be selected and the tack can be set at the proper angle by rotating the control ring 74 while viewing the angle of the end cylinder 80, until perpendicularity is achieved. Then the tack 24 can be extended by shifting the transverse arm 102 relative to the positioning slot 104. Thereafter the impeller 114 attached to the threaded end 112 of the shaft mechanism 100, can be actuated for driving the tack into position. A previously inserted tack which is to be removed, or a faultily inserted tack, can be removed by engagement of the arms 109, 110 into the space between the double heads of the tack 24, and undertaking the repeated tapping action in the reverse direction. For this purpose, however, a double acting pneumatic impeller or a reversed impeller is to be used. 
     Another useful feature that may be employed in either system is shown in FIGS. 11 and 12. In this example, in which only the terminal end fragment of a laparoscopic tacker is seen, the central positioning mechanism terminates in a ball 130, and the tack holder is in the form of a cartridge 132 having a fictionally engagable socket 134 which partially encircles the ball 130 at the end of the shaft. To insert a new tack for a given application, the laparoscopic tacker is removed, the prior cartridge is disengaged and a new cartridge, with pre-loaded tack attached, is substituted. This can be effected rapidly during a surgical procedure, so that several tacks can be embedded serially or tack sizes can be changed. 
     The embedded tack can serve other purposes in addition to attachment of an element to cartilage. Thus as seen in FIGS. 13 and 14, a tack 24a may have slots or notches 140 at diametrically opposed positions in the periphery of the b a upper head 58. A suture filament 142 may then be wrapped about half or the full circumference of the groove between the heads 58, 59 and taken out through the notches 140, so that the tack 24a serves as a temporary anchor or a permanent attachment point for the suture. 
     The pneumatic impeller 114 discussed in connection with the example of FIGS. 7-10 may be utilized as shown in FIG. 15 and constructed as seen in FIG. 16. With a compact, light weight impeller 114 attached to the instrument 20, only a pneumatic line 144 is added to the manipulated mass. This line 144 transports pneumatic impulses at a chosen periodicity from an impulse generator 146 (eg a reciprocating pump) which is activated by a controller 148, which is preferably remote, such as a fast pedal, or may be on the instrument 20 itself. If desired the pulses may be modulatable to deliver strokes of varying amplitude, frequency, or both. 
     An unidirectional pneumatic impeller 114 is depicted in FIG. 16, for use in embedment of a tack--if a pneumatic action is desired, then the arrangement must be double-ended or a complementary impeller operating in the reverse direction must be attached. For brevity, however, only the embedment direction is described since this is the mode that is typically employed. 
     The pneumatic impeller 114 comprises a cylinder chamber 150 within which a free piston 152 is engageable against the flat end 154 of a positioning and driving shaft 156 that extends through the instrument 20. A spring 158 within the chamber 150 biases the piston 152 in a direction away from the distal end, and a port 160 in this end of the chamber 150 prevents pressure buildup, although O ring seals 162 about the piston 152 prevent bypass. Pneumatic impulses are fed from the line 144 into a pressure compartment 164 within the chamber 150, overcoming the spring 158 compliance and impacting the piston 152 down against the flat end 154 of the shaft 156. By controlling the pressure differential end duration, the desired periodic tapping force is achieved. A relief post 170 in the wall of the pressure compartment 164 is closed as the impulse is received, by a bypass flow from the line 144 into a secondary chamber 172 containing a reciprocable small piston 174 to which a valve 176 is attached. A spring 178 normally holds the valve 176 open, allowing air to escape from the pressure compartment 164 via an exhaust port 180, when the larger piston 152 returns, so that reciprocation can take place without lessening the needed impact force for embedment. 
     Although a number of forms and variations have been described, it will be appreciated that the invention is not limited thereto but encompasses all modifications and expedients within the scope of the appended claims.