Abstract:
A device and method for deploying helical fasteners which may be used to attach a prosthesis to tissue, e.g., to attach a mesh patch in a hernia repair procedure. A helical coil fastener which is inhibited from undesirable migration after installation is also provided.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to surgical fasteners. In particular, the invention relates to helical fasteners and a means for containing and applying a plurality of them in the course of laparoscopic surgery.  
         BACKGROUND OF THE INVENTION  
         [0002]    The time consuming processing of traditional suturing necessitated the development of surgical fasteners. By shortening the time of the suturing process, surgical fasteners reduce blood loss and trauma to the patient. For open surgery, there has been a substantial amount of activity in developing staples and staple applicators to be used to secure tissue elements, e.g., in wound closure. Staples have also found use in attaching prostheses, e.g., the mesh patches used to repair hernias.  
           [0003]    The use of staples has now become widespread, but with the advent of minimally invasive, or laparoscopic, surgery, the amount of room available for fastening devices to operate in has decreased substantially. In addition, in some instances, e.g., laparoscopic hernia repair, the surgeon has access to only one side of the tissue to which the mesh patch is to be secured.  
           [0004]    Furthermore, stapling of a mesh patch in a hernia repair procedure generally requires the exertion of axial force on the staple and the creation of a counter-force (such as that provided by an anvil when a stapler is used in open surgery) can be difficult. Thus, a need arose for a fastening means and applicator system which would not be subject to these difficulties.  
           [0005]    One answer to these problems was provided by the use of helical coil fasteners, such as those described in Gianturco U.S. Pat. No. 5,258,000 and Bolduc U.S. Pat. Nos. 5,582,616; 5,810,882; 5,824,008; the disclosures of which are incorporated herein by reference in their entireties, which were developed as an alternative to staple fasteners. Some suture devices have also made use of helically coiled components, such as those disclosed in Yoon U.S. Pat. No. 5,053,047 and Buzerak U.S. Pat. No. 5,356,424, the disclosures of which are incorporated herein in their entireties. Since a helical fastener is driven through the items to be attached, e.g., a mesh patch and underlying tissue, by the rotational driving force of the helical coil, the need for axial pressure is greatly reduced. The Bolduc embodiment of a helical coil fastener device includes a helical coil and an applicator. The helical coil has a distal end adapted to penetrate tissue and a proximal end capable of receiving longitudinal and rotational force from the applicator. The applicator can comprise a stationary hollow tube adapted to contain one or more fasteners. Additionally, there may be a movable rod within and sharing an axis with the hollow tube. The rod may have a groove running longitudinally along its length or be “D” shaped, whereby it is adapted to engage the fastener. The rod may further be adapted to be able to apply longitudinal and rotational force to the fastener. Helical coil fasteners may be applied to tissue accessible from one side and, also, have a large retentive surface area for securing a prosthesis, e.g., a mesh, to the tissue.  
           [0006]    The manner in which the helical coil engages a rotator designed to impart rotational motion to the coil is important for ease of use. The present invention, unlike previous helical coil fastener systems, employs a groove in the rotator which is engaged by a protuberance extending from the helical coil. Such an arrangement has the advantages of simplicity and ease of use. Additionally and separately, the present invention also contemplates providing a helical coil fastener which is provided with means designed to prevent migration of the coil out of its desired location after it has been installed.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention is directed to an improved fastener and applicator for inserting the fastener into tissue.  
           [0008]    The preferred embodiment of the fastener comprises a short helical coil. At the distal end of the wire or similar material forming the coil is a point or other configuration suitable for passing through mesh and piercing tissue. At the proximal end of the coil is a protuberance extending outside the circumference of the helix, radially or obliquely. The protuberance must be extensive enough to engage a first coil engaging means such as a slot or keyway in or on the interior surface of the distal end of an applicator tube. Preferably, the protuberance does not extend beyond the exterior surface of the applicator tube. The fastener may be made of any material suitable for medical implantation, including but not limited to metal, plastic or absorbent materials. Titanium is a preferred material.  
           [0009]    An alternate embodiment of the fastener provides a loop at the proximal end to prevent the fastener from continued migration through the tissue and/or to prevent disattachment of a mesh or other prosthetic element attached to the tissue by the fastener. The loop interrupts the continuous form of the helix, thereby providing greater resistance to undesired movement.  
           [0010]    When the distal end of the fastener is held against or in proximity to a mesh patch or other entity which is to be attached to tissue into which the fastener is to be placed, and the fastener is turned about its longitudinal axis, it will advance helically and pass through the mesh or other entity and into the tissue thereby attaching such entity to the tissue.  
           [0011]    The preferred embodiment of the applicator comprises a delivery tube that is adapted to contain a plurality of fasteners, but also contemplates a device having a delivery means adapted to hold only one fastener at a time. The applicator tube also functions as a driving means to rotate the fastener contained therein. The applicator tube is slotted or grooved along its longitudinal axis. This slot or groove engages the protuberance on the proximal portion of the fastener, allowing the tube to exert rotational force on the fastener. The length of the tube must be suitable to reach the operative site from outside the patient. The inside diameter of the tube should be large enough to allow translation of the fasteners contained therein while at the same time being small enough to maintain driving contact with the protuberance on the fastener.  
           [0012]    The preferred embodiment further comprises a stationary stabilizer rod. The rod is contained within the tube. The rod is sized to slide within the helical coil of the fasteners. At or near the distal tip of the rod is a coil engaging means which engages the fastener. This means may be a radially outwardly extending pin, a thread form matching the helical coil of the fastener, a plurality of radially outwardly extending pins positioned to match the helical coil of the fastener or any other form that functions to engage the fastener. Once the protuberance on the fastener is in engagement with the slot in the tube and the coil of the fastener is in engagement with the coil engaging means, the tube is rotated, thereby rotating the fasteners, and the fasteners are thus advanced in the manner of a screw. If a multiple fastener device is desired, the fasteners may be stacked successively within a tube of desired length and in such a device the rod and coil engaging means will preferably be lengthened to engage all fasteners such that all are distally advanced together upon rotation of the applicator tube.  
           [0013]    In an alternate embodiment, a loading spring may operate in the annulus between the tube and rod. The loading spring functions to bias the fasteners toward the distal tip of the applicator tube. As a result, upon rotation of the tube, the fasteners are successively urged into engagement with the coil engaging means at or near the distal portion of the rod. The loading spring must be of adequate length and sufficient force to cause all fasteners, in turn, to engage the coil engaging means on the rod. Preferably, the loading spring may rotate with the tube. In an alternate embodiment, the loading spring may be stationary with respect to the tube. Advantageously, a means to provide a non-tangling interface such as a washer is provided at the distal end of the loading spring and is in contact with the most proximal fastener and may also optionally provide a visual indication when all fasteners have been ejected.  
           [0014]    The applicator further comprises a handle at the proximal end of the applicator. A suitable handle must fix the stabilizer rod and must rotate the applicator tube. The handle may, advantageously, rotate a measured amount to eject one fastener at a time. Preferably, the handle further comprises a clutch mechanism which prevents counter-rotation of the tube.  
           [0015]    Although helical coil fasteners are preferred, other shapes which may be used according to the present invention include any suitable circular or cylindrical or conical shape in which generally circular loops are used.  
           [0016]    Other objects and advantages of the present inventions will become apparent from the detailed description of the preferred embodiments which follow. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 shows a slide view of a rotatable hollow tube according to the invention, with a slot running longitudinally along the distal portion.  
         [0018]    [0018]FIG. 2 shows a side view of a stationary stabilizer rod according to the invention, with a coil engaging means near the distal tip and a loading spring and washer near the proximal end.  
         [0019]    [0019]FIG. 3 shows a side view of a fastener according to the invention.  
         [0020]    [0020]FIG. 4 shows an end view of a fastener according to the invention.  
         [0021]    [0021]FIG. 5 shows an end view of a fastener engaged in a rotatable hollow tube according to the invention. A protuberance extending from the blunt end of the spring mates with a longitudinal slot in the tube.  
         [0022]    [0022]FIG. 6 shows a schematic partial cross-sectional view of the interrelationship between a fastener, a rotatable hollow tube, and a stationary stabilizer rod.  
         [0023]    [0023]FIG. 7 shows an embodiment of the applicator device used to deploy the fastener.  
         [0024]    [0024]FIG. 8 shows an alternate embodiment of a rotatable hollow tube having a slot or keyway that runs longitudinally along the distal portion.  
         [0025]    [0025]FIG. 9 shows an alternate embodiment of a stationary stabilizer rod with a thread form matching the fastener helix located near the distal tip.  
         [0026]    [0026]FIGS. 10 a  and  10   b  show an alternate embodiment of a fastener with a loop near the blunt end.  
         [0027]    [0027]FIG. 11 shows an end view of an alternate embodiment of a fastener according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]    As is shown in the drawings, which are offered for purposes of illustration and not be way of limitation, the invention is embodied by a helical fastener and an applicator therefor. One embodiment of the applicator of the present invention, as seen in FIGS.  1 - 5 , comprises a rotatable hollow tube  10  that drives a fastener  30  into tissue. The tube  10  must be of a length suitable to reach the operative site from outside the patient. The fastener  30  may be further guided by a stationary stabilizer rod  20 . It is preferred that the rotatable hollow tube  10  and the stationary stabilizer rod  20  are of such dimensions that the fasteners  30  can be placed between and in contact with both the tube  10  and the rod  20  and also slide without excess friction along the rod  20  and within the tube as shown in FIG. 6.  
         [0029]    In a preferred embodiment of the invention (See FIG. 1), the rotatable hollow tube  10  has a longitudinal slot  12  along a distal portion  14  thereof. The slot  12  may of any length, but preferably is of a length equal to or greater than the length of the fasteners in tube  10 . It is also desirable that slot  12  be evenly divisible by one fastener length.  
         [0030]    In one preferred embodiment of the invention (See FIG. 2), the stationary stabilizer rod  20  has a second coil engaging means such as pin  22  at the distal portion  24  of the rod. The pin  22  may be of any height  28 , but is preferably of such a height that the pin  22  is flush with the outer portion of the rotatable hollow tube  10 . The pin  22  is shown as having a generally square shape, but may be of any shape capable of engaging a fastener  30 .  
         [0031]    As seen in FIGS. 2 and 6, a loading spring  26  may operate at the proximal portion of the rod  20 . The loading spring  26  acts to bias the fasteners  30  toward the pin  22 . Advantageously, the loading spring  26  may rotate with the tube  10 . However, the loading spring  26  may be stationary. The loading spring  26  should be of sufficient length and adequate force to urge all fasteners  30  in turn into engagement with second coil engaging means  22 . Preferably, a washer  20  may be located at the distal tip of the loading spring  26 . The washer  29  functions to provide a non-tangling interface with the most proximal of the fasteners  30  and, optionally, to provide visual indication when all fasteners  30  have been ejected. Additionally, in place of the washer  29 , any other suitable means that may provide a non-tangling interface or visual indication may be used.  
         [0032]    In a preferred embodiment of the invention (See FIGS. 3 and 4), the fastener  30  has a helical shape. The length, pitch, and diameter of the coil may be varied depending upon the application. Additionally, the fastener  30  may be of any suitable circular, cylindrical or conical shape in which generally circular loops are used. Moreover, the fastener  30  has a piercing end  38  that may be of varying form or sharpness, depending on the application. The proximal end  40  of the fastener  30  should have a protuberance  42  extending beyond the diameter  36  of the fastener. The protuberance  42  may extend any length outside the diameter  36  of the fastener  30 , but preferably extends a length less than or equal to the thickness of the rotatable hollow tube  10  (See FIGS. 5 and 6).  
         [0033]    As shown in FIG. 7, applicator  80  has a handle  81  and an actuator  82 . The applicator is equipped with a tube member such as tube  10  having a slot such as slot  12 . In operation, the actuator  82  functions to rotate tube  12  which drives the helically coiled fastener out of the applicator and into the tissue of the patient. The applicator is provided with lever  83 . As shown in FIG. 7, the lower end  84  of the lever  83  is a trigger-like member suitable for manual manipulation. The other, or upper, end  85  of lever  83  engages driver  86 . Lead screw  87  which has a helical thread thereon is rotatably mounted in the applicator and engages driver  62 . The longitudinal axis of tube  10  is coaxial with the longitudinal axis of screw  87 .  
         [0034]    When the trigger end  84  of the lever  83  is squeezed, the driver is moved along screw  87  causing it to rotate. This, in turn causes, tube  12  to rotate thereby causing the helical coil fasteners in tube  12  to move distally through the tube. Preferably, the length of travel of the coil fasteners resulting from one squeeze of the trigger will be just enough to force one coil fastener out of tube  12  and will then leave the next fastener at the distal end of tube  12  ready to be discharged on the next trigger squeeze.  
         [0035]    When trigger portion  84  is squeezed, lever  83  pivots on its center of rotation  88 . Lever  83  can be provided with a spring loaded pawl  89  adapted to engage teeth  90  such that one full pull of the trigger is required before the trigger can be returned to its undepressed position. This assures that each pull of the trigger will fully discharge one fastener.  
         [0036]    In one alternate embodiment of the invention shown in FIG. 8, the rotatable hollow tube  10  has a longitudinal groove or keyway  50  along the inner surface of tube  10  instead of a slot in the tube. The groove  50  acts to engage the protuberance  42  of the fastener  30 , thereby applying rotational force to the fastener  30 .  
         [0037]    In another alternate embodiment of the invention, as seen in FIG. 9, the stationary stabilizer rod  20  has a thread form  60  that mates with the coil of the fastener  30 . Specifically, the thread form  60  engages the fastener helix, thereby cooperating with rotation of tube  10  to advance the fastener  30  into tissue in a screw-like manner upon rotation of tube  10 . Optionally, a plurality of pins may be positioned to form a thread that mates with the fastener helix. If the length of the thread is at least as long as the stack of fasteners carried in the tube  10 , the load spring may be eliminated.  
         [0038]    In still another alternate embodiment of the invention, as seen in FIGS. 10 a  and  10   b , a fastener  70  may have a loop portion  72  near the blunt end. Preferably, the loop portion  72  has a connected end  74  and a free end  76 . Optionally, both ends may be connected (not shown). In the embodiment having only one connected end, the loop portion  72  may extend beyond the diameter of the helical body of the fastener  70  at the connected end  74 . The loop portion  72  may extend any length beyond the diameter of the fastener  70 , but preferably extends a distance less than or equal to the thickness of the rotatable hollow tube  10 .  
         [0039]    The alternate fastener embodiment shown in FIG. 1I has a trailing tail  79  which extends outside tube  10  and is driven by the offset portion of tail  79  which engages slot  12 .  
         [0040]    Certain embodiments have been described herein, and are illustrated in the drawings. However, it will be apparent to those skilled in the art that modifications can be made to the embodiments without departing from the inventive concepts described. Accordingly, the invention is not be to restricted except by the claims which follow.