Abstract:
A surgical fastener system is disclosed. The system includes a surgical fastener, a surgical fastener holder sized and shaped to receive the surgical fastener at least partially therein, and a surgical fastener driver having a seat sized and shaped to frictionally receive a head of the surgical fastener therein. The fastener driver is constructed and arranged to selectively urge the fastener, and more particularly the fastener head, out of the seat. The surgical fastener driver thus includes an elongate body with the seat defined at an end thereof, and a drive piston disposed within the body. The drive piston has a first retracted position, and a second extended position in which at least a portion of the piston extends into the seat to urge the fastener out of the seat during usage. Also disclosed is a surgical fastener and a surgical fastener holder, respectively, for use with the system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This patent application claims priority to U.S. Provisional patent application Ser. No. 60/111,828, filed on Dec. 11, 1998, and is a continuation application of U.S. patent application Ser. No. 09/458,914, filed on Dec. 10, 1999, respectively, in the United States Patent and Trademark Office. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention relates to medical devices generally, and more particularly to systems for applying surgical fasteners that secure membranes to biological tissues such as bone.  
         BACKGROUND OF THE INVENTION  
         [0003]    In surgery, for example reconstructive oral or dental surgery, when grafting bone a membrane is placed over the bone to allow the bone to regrow without contamination. The membrane is typically fastened to the bone using screws or hand-driven tacks. Because the screws used are small, and therefore hard to drive into bone, they currently are rarely used in oral surgery.  
           [0004]    Hand driven tacks are more commonly used. In use, the tacks are held by a pick up tool and driven into position with a mallet. The tacks may also be pushed into position by hand. The tools employed with tacks, however, tend to be bulky and, given that the tacks used tend to be small, the tacks are hard to handle.  
           [0005]    There is a need, therefore, for a surgical fastener system that facilitates the handling and use of tissue tacks in dental surgery  
         SUMMARY OF THE INVENTION  
         [0006]    One aspect of the invention is a surgical fastener driver having a handle and a tube extending therefrom. The handle defines a cavity therein. The tube is in communication with the cavity and is affixed to the handle. The tube extends outwardly from the cavity to a seat, which is shaped so as to receive a surgical fastener therein. A piston, having an outward end, is disposed within the tube and extends from the cavity to the seat. The piston has a retracted position in which the outward end does not extend into the seat, and an extended position in which the outward end extends into the seat.  
           [0007]    A trigger is integrated with the handle of the fastener driver, and has a first state in which the piston is held in the retracted position, and a second state in which the piston is released so as to allow the piston to move to the extended position. A driver is disposed within the cavity and exerts an outward force on the piston in order to drive the piston into the extended position when the trigger is moved into its second state.  
           [0008]    In another aspect, the invention is a surgical fastener for securing surgical membrane materials to body tissues (such as bone). The fastener includes a tack that includes an elongate stem having a proximal end and a distal end, a head disposed at the proximal end of the stem, and a plurality of discrete axially spaced annular ribs disposed in successive longitudinal positions along the stem. The head has a diameter sized to frictionally fit within the seat of a delivery device, which may include, for example, the surgical fastener driver described above.  
           [0009]    In yet another aspect, the invention is a holder for surgical fasteners that includes a first block and a second block. The first block has a top surface and defines a plurality of cavities opening to the top surface, wherein each cavity is shaped so as to be capable of receiving a tack therein. The second block has an upper surface and an opposite lower surface complementary in shape to the top surface of the first block. The second block defines a plurality of holes passing from the upper surface to the lower surface, each of which is in alignment with a corresponding cavity in the first block when the lower surface of the second block is placed against the top surface of the first block. A loading pin is disposed within a selected one of the plurality of cavities through at least a portion of the corresponding hole.  
           [0010]    These and other aspects of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1A is a schematic illustration of a surgical fastener driver of the present invention.  
         [0012]    [0012]FIG. 1B is an enlarged partial schematic view of a surgical fastener positioned within a seat defined at an end of the surgical fastener driver of FIG. 1A, with an outward end of a driver piston shown in a retracted position.  
         [0013]    [0013]FIG. 1C is an enlarged partial schematic view of the seat of the surgical fastener driver of FIG. 1A with the outward end of the driver piston shown in an extended position.  
         [0014]    [0014]FIG. 1D is an elevational view of a trigger assembly for use with the surgical fastener driver of FIG. 1A.  
         [0015]    [0015]FIG. 2A is a cross sectioned elevational view of a plurality of surgical fasteners or tacks connected to one another by a common runner.  
         [0016]    [0016]FIG. 2B is a top plan view of the surgical fasteners of FIG. 2A.  
         [0017]    [0017]FIG. 3A is a perspective view of a surgical fastener holder of the present invention.  
         [0018]    [0018]FIG. 3B is a cross sectioned elevational view of the holder of FIG. 3A. 
     
    
     DETAILED DESCRIPTION  
       [0019]    A preferred embodiment of the invention is now described in detail. Referring to the drawings, like numbers indicate like parts throughout the several views. As used in the description herein and throughout the claims that follow, the words “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. Also, “complimentary in shape” means having generally compatible dimensions, without necessarily having an identical shape.  
         [0020]    As shown in FIGS.  1 A- 1 D, the surgical fastener driver  10 , according to one illustrative embodiment of the invention, includes a handle  20  that defines a cavity  30 . The cavity  30  is cylindrical and has a smaller elongate alignment cavity  32  defined therein and extending axially away therefrom. The handle  20  may be machined from a metal, such as aluminum, stainless steel, or any desired one of the many metals typically used in the manufacture of medical instruments, or from other materials generally known in the art. A tube  40  extends from the cavity  30  and is affixed to the handle  20 . The hollow core of the tube  40  is in communication with the cavity  30 . The tube  40  ends in a seat  42  that is sized and shaped to receive a surgical fastener  102  therein. The tube  40  may be strengthened without increasing its bulk near the seat  42  by including a taper  44 , thereby allowing for the use of narrower tubing near the seat  42 . The tube also includes a first section  46  and a second section  48 . The second section  48  deflects at an angle away from the first section  46  to facilitate the placement of surgical fasteners in hard to reach areas.  
         [0021]    Referring now to FIG. 1A, a piston  50 , having a first elongate portion  58  terminating in an outward end  52 , is disposed within the tube  40  and extends from the cavity  30  to the seat  42 . The piston  50  as constructed has the first elongate portion  58 , and a second portion  56 . As illustrated, the cross-section of the second portion  56  is greater than the cross section of the first portion  58 . As illustrated in FIG. 1B, the piston  50  has a retracted position in which the outward end  52   a  thereof does not extend into the seat  42 , so that a surgical fastener  102  may be held in the seat  42 . As illustrated in FIG. 1C, the piston  50  also has an extended position in which the outward end  52   b  thereof extends into the seat  42 . When the piston  50  is forced into the extended position, the surgical fastener  102  is thus forced out of the seat  42 . Accordingly, should the seat  42  be placed against a membrane (not illustrated), the surgical fastener  102  is forced into the membrane, thereby fastening it to the underlying bone (not illustrated) in the patient&#39;s mouth.  
         [0022]    The fastener driver also has a trigger  60  integrated with the handle  20 . The trigger  60  has a first state in which the piston  50  is held in the retracted position (FIG. 1A) and a second state in which the piston  50  is released so as to be allowed to move into its extended position (FIG. 1B). As shown in detail in FIG. 1D, the trigger  60  includes a locking member plate  62  that defines a hole  64  passing therethrough. The hole  64  includes a small portion  68  that allows the first elongate portion  58  of the piston  50  to pass therethrough, but prevents the second portion  56  of the piston from passing therethrough, i.e., the small portion holds the piston within the cavity  30  in the piston&#39;s retracted position. The small portion  68  thus restricts the piston  50  when the plate  62  is in a first position corresponding to the first state of the trigger  60 . The hole  64  also has a large portion  66  that allows both the first portion  58  and the second portion  56  of the piston to pass therethrough when the plate  62  is in a second position corresponding to the second state of the trigger  60 . The trigger  60  also includes a second spring  70  that maintains the locking member plate  62  in the first position until it is pushed down, thereby releasing the piston  50 .  
         [0023]    A driver  80  adapted to exert an outward force on the piston  50  is disposed within the cavity  30  as illustrated. The driver  80  drives the piston  50  into its extended position when the trigger  60  is moved into its second state. As shown in the illustrative embodiment, the driver  80  includes a spring  82  that applies force to a plunger head  84  that caps one end of a plunger cylinder  86 . The plunger head  84  has dimensions complimentary to that of the cavity  30  so as to be able to slide back and forth within the cavity  30 . The rod of the plunger cylinder  86  fits within the elongate alignment cavity  32  to maintain the alignment of the plunger head  84  within the cavity  30 . The spring  82  applies force on the plunger head  84 , which in turn applies force to the piston  50 , thereby causing the piston  50  to force the surgical fastener  102  into the patient&#39;s tissue (not illustrated) when the trigger  60  is actuated to release the piston  50 .  
         [0024]    As shown in detail in FIG. 1B, one example of a surgical fastener  102  adapted for securing surgical membrane materials to body tissues is a tack that includes an elongate stem  114  having a proximal end and spaced distal end. The tack could comprise, for example, a bio-absorbable material (such as PLLA) or a medical grade metal. A head  108  is disposed at the proximal end of the surgical fastener, or tack, and the distal end terminates at a point  112 . A plurality of discrete axially spaced annular ribs  110  is disposed in successive longitudinal positions along the stem  114 . The head  108  has a diameter sized to frictionally fit within the seat  42  of the delivery device  10 , i.e., the fastener driver.  
         [0025]    As shown in FIGS. 2A and 2B, a tack strip  100  may be formed of a plurality of fasteners  102   a - c  connected to one another by an integrally formed linear runner  104 . Such a tack strip  100  would facilitate ease of use with a surgical fastener holder  200 , as shown in FIGS. 3A and 3B.  
         [0026]    The holder  200  includes a first block  210  and a second block  220 . The first block  210  has a top surface  214  within which a plurality of cavities  212  are defined. Each cavity  212  is sized to be capable of receiving a tack therein. The second block  220  has an upper surface  228  and a spaced opposite lower surface  226  which is complementary in shape to the top surface  214  of the first block  210 . The second block  220  defines a plurality of holes  222  passing therethrough so that each of the plurality of holes  222  is in alignment with a corresponding cavity  212  in the first block  210  when the lower surface  226  of the second block  220  is placed against the top surface  214  of the first block  210 . A loading pin  216 , for use with the fastener driver, as described in greater detail below, is disposed within a selected one of the plurality of cavities  212  and extends through at least a portion of the corresponding hole  222 .  
         [0027]    If the holder  200  is to be reusable, both the first block  210  and the second block  220  should comprise a material able to withstand standard sterilization techniques (such as exposure to high temperature or radiation). For example, in one embodiment, metal is used to construct the holder. If the holder  200  is to be disposable, then one of many materials known to those of skill in the art could be used (e.g., polycarbonate).  
         [0028]    To facilitate the alignment and securing of the first block  210  to the second block  220 , one or more pins  218  (FIG. 3B) may be added to extend from the top surface  214  of the first block  210  and one or more holes  224  (FIG. 3B) may be defined within the lower surface  226  of the second block  220 . Each hole  224  is complementary in shape to, and in alignment with, a selected (corresponding) pin  218 . As is readily understood, the pins  218  could extend from the second block  220  while the holes extend into the first block  210  without departing from the scope of the invention.  
         [0029]    Referring now to FIGS.  1 A- 3 B, in use the tack strip  100  is placed within or on the first block  210  of the holder  200 , as illustrated, so that the individual surgical fasteners or tacks  102  extend into and fit within the respective cavities  212 . The second block  220  is then secured to the first block  210  as described above. The operator then prepares the fastener driver  10  for use by forcing the outward end  52  of the piston  50  down onto the loading pin  216  which will, in turn, force the piston  50  back into the cavity  30  until the trigger  60  locks the piston into its retracted position. The seat  42  is then placed over one of the available surgical fasteners  102  in the holder  200  and pushed down until the selected surgical fastener  102  breaks away from the runner  104  and fits frictionally within the seat  42  (FIG. 1B). The seat  42  is then placed against the membrane (not illustrated) to be fastened, the locking member plate  62  is pressed down to release the piston  50  from its retracted position, and the surgical fastener  102  is forced by the piston into and through the membrane and the into the tissue (not illustrated) to which the membrane is to be fastened.  
         [0030]    The embodiments described herein are presented as illustrative examples only, and are not intended to impose any limitations on the invention. It will be readily appreciated by those skilled in the art that many alternate embodiments may be made from the specific embodiments disclosed in this specification without departing from the invention. Accordingly the described embodiments are intended to cover all such modifications coming within the anticipated scope of this invention.