Abstract:
A needle driving apparatus for sternal closure following sternotomy. Accessory elements include: 1) a straight surgical needle absent attached suture and 2) a separate suture carrying small cylinders at opposing ends. Apparatus provides a dual capability of 1) needle penetration of sternum from top surface and 2) precise positioning of cylinder at undersurface of sternum. The apparatus is a handled framework supporting a rachet type drive assembly which includes a lever, a pawl, biasing springs and a toothed arm which carries a needle. A framework extension carries a socketed fixture. The fixture precisely positions a cylinder and its suture in the socket. When the lever is taken up by hand, motion is imparted to the arm and needle. The needle penetrates the sternum, then the cylinder, where it becomes locked therein by friction. Retrograde extraction of needle (using a conventional needle driver) delivers the suture by shuttle action to its desired position, atop the sternum. Repetition on the procedure described, on the opposing side of the sternum completes the placement of a single suture.

Description:
CROSS REFERENCE TO RELATED APLICATIONS  
       [0001]     This application is related to application Ser. No. 10/119,554 filed Apr. 10, 2002. 
     
    
     BACKGROUND, FIELD OF THE INVENTION  
       [0002]     The invention is a surgical instrument that provides a new and improved method for sternal closure. The new method is easier, more precise and safer than that as practiced in prior art.  
       BACKGROUND, DISCUSSION OF PRIOR ART  
       [0003]     Presently, sternal closure with surgical stainless steel sutures is practiced almost universally. The process is described in detail to allow comparison with the new method and apparatus. Sutures are supplied commercially with a large curved needle attached to a single end. The needle is grasped with an instrument called a needle driver. The surgeon is required to pass the needle through the sternum by applying a force to the needle driver with one hand, while applying an opposing force on the undersurface of the sternum with the other hand. Thus, the needle passes through the sternum in a direction, from outside grasped with the needle driver and pulled through to the inside. The suture needle must now be passed in a direction from inside to outside on the opposing side of the sternum, using the needle driver. Multiple sutures are placed in this manner to complete the closure.  
         [0004]     Problems associated with this method of closure are listed below. 
        1. Significant stress is placed on the hands of the surgeon.     2. Bent or broken needles occur as a result of difficulty in passing a curved needle through the bony sternum.     3. There is frequently difficulty controlling the path of the curved needle, resulting in imprecise suture placement.     4. The surgeon&#39;s hand is placed in harms way for possible needle puncture and exposure to serious blood born disease.        
 
       OBJECTS AND ADVANTAGES OF NEW SUTURE APPARATUS AND METHOD  
       [0009]    
       
         
           
              1. The apparatus uses straight rather than curved needles, allowing for precise and predictable placement of sutures.  
              2. The mechanical advantage provided by the apparatus allows the sutures to pass through the sternum with relative ease, significantly reducing stress on the surgeon&#39;s hands.  
              3. The incidence of bent or broken needles is reduced.  
              4. The apparatus provides the opposing force required at the undersurface of the sternum, thus protecting the surgeon from possible needle puncture of the hand and the risk of exposure to blood born disease.  
              5. elimination of sharp needle tips provides further protection from needle puncture of hands. 
 
 Further objects and advantages of the invention will become apparent from a consideration of the drawings and the ensuing description 
 
           
         
       
     
         [0015]     Having considered the art in terms of method, it will be helpful to examine hardware; the instruments, sutures and needles used in the suturing process. The basic tool for passing sutures through tissues is called a needle driver. It is essentially a streamlined pliers, capable of locking jaws to hold a needle. The tool has changed little over the years. On the other hand, needles and sutures and their relationship have changed considerably. Needles and sutures evolved as separate entities. Needles were made with an eyelet. A strand of suture “threaded” the needle in preparation for use. Needles were sterilized and reused many times over.  
         [0016]     By the early nineteen sixties technology had developed whereby a disposable needle was “swedged on” to its suture. Advantages included very sharp needles and streamlined passage through tissues. By the late nineteen sixties, all sutures were of this type. The sutures currently in use for sternal closure use such needles,  
         [0017]     Sternal closure presents special problems. To begin, the needle must be passed through bone. In addition, there are serious space constraints as the heart lies immediately beneath the sternum. The ongoing use of curved needles relates to the space problem.  
         [0018]     The advantages of the use of straight needles for sternal closure have been recited. The new apparatus and method permit such use by utilization of suture and straight needle as separate entities.  
       SUMMARY OF THE INVENTION  
       [0019]     The problems discussed above are addressed and at least partially solved with the improved suturing apparatus and methods. In a particular apparatus embodiment, disclosed is a handled framework that supports opposing, coactive male and female engagement elements. The female engagement element carries a suture and fits into a socket in which it is secured in a precise position. The male engagement element is a straight surgical needle carried in an arm and reciprocated to the handled framework in opposition to the female engagement element. A drive assembly attached to the handled framework is capable of imparting linear motion to the arm. Preferably, the drive assembly includes a set of inclined teeth or detents, carried by the arm, a pawl capable of interacting with the inclined teeth and a lever, pivoted to the handled framework and thence to the pawl. The pawl is moveable in reciprocal directions in response to pivotal movement of the lever. Lever motion imparts linear motion to the arm and the needle carried therein.  
         [0020]     A needle guide or stabilizing device is moveably attached to a perpendicular extension of the handled framework. The needle guide is positioned intermediate to the male and female engagement elements. The guide carries an aperture through which the surgical needle must pass prior to penetration of the sternum, en route to the female engagement element. The method for using the suture apparatus herein disclosed will now be summarized. 
        The apparatus is positioned to place the sternum intermediate to, the male and female engagement elements.     A force is applied to the lever and repeated as necessary to accomplish penetration of the sternum and engagement of the male and female engagement elements. The lever will bias to the open position as manual pressure is released.     As linear movement is imparted to the arm and the needle it carries, the needle passes sequentially through the needle guide and bony sternum and then into the female engagement element. Although the needle tip is of slightly greater outside diameter than the inside diameter of the female engagement element, the needle penetrates and becomes trapped therein by friction The apparatus is then disengaged from the suture and removed from the site to be reloaded.     The needle can now be extracted in a retrograde direction using a conventional needle driver, thus delivering the suture through the sternum.     The steps described above are then repeated on the opposing side of the sternum, which completes the placement of a single suture.        
 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is a perspective view of the apparatus in its environment, between cut sternal edges.  
         [0027]      FIG. 2  is a side view of the apparatus showing the engagement elements in position for use and hidden lines revealing portions of the drive assembly.  
         [0028]      FIG. 3  is a side view of the apparatus showing the male engagement element having penetrated the sternum and the lever in closed position.  
         [0029]      FIG. 4  is a frontal view of the apparatus, with the engagement elements in position for use.  
         [0030]      FIG. 4A  is a sectional view through section lines A-A Needle guide has not been moved to a lower position for use.  
         [0031]      FIG. 5  is an exploded view of the needle guide as it mounts the perpendicular extension.  
         [0032]      FIG. 5A  is a sectional view through section lines D-D.  
         [0033]      FIG. 6  shows the upper and forward portion of the handled framework and arm. Emphasis is directed to the exploded view of the friction device and its relation to the arm.  
         [0034]      FIG. 6A  is a sectional view through section lines C-C.  
         [0035]      FIG. 7  is a perspective view of the fixture, as viewed from its inferior surface. Line D shows the position of the female engagement element seated in the socket. (Socket not shown). The circular arrowed lines refer to reciprocal rotary motion of the knob, which opens or closes the fixture.  
         [0036]      FIG. 7A  is a sectional view through section lines A-A.  
         [0037]      FIG. 7B  is a sectional view through section lines B-B.  
         [0038]      FIG. 8  is an exploded view of the proximal, bifurcate portion of the lever, also showing the pawl and pivot pin that fit into the space created by the bifurcation.  
         [0039]      FIG. 8A  shows perspective views of one embodiment of the male and female engagement elements.  
         [0040]      FIG. 9  is a perspective view of a second preferred embodiment of the needle guide showing the grooved piston in its cylinder and male engagement element in place.  
         [0041]      FIG. 9A  is a sectional view through section lines E-E.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0042]     The preferred embodiment includes: the handled framework  251 , a friction device  274 , a needle guide  255 , the arm  270 , the drive assembly  280 , a fixture  253 , male engagement element  252 , and female engagement element  254 . In order to make the more detailed description, which follows as simple, clear and concise as possible, the components will be described separately. It should be noted, that in describing one component, it is often necessary to make reference to another.  
         [0043]     As shown in  FIG. 1 , handled framework  251  includes a handle  260  with opposing forward extremity  261  and a rearward extremity  262 . A perpendicular Extension  263  is offset rearward of forward extremity  261  and extends distally, terminating at distal extremity  264 . An enlarged seat  265  extends forward at distal extremity  264 . Forwardly and inferiorly, a horizontal margin  258  of handle  260  extends anteriorly from leading edge  266  to forward extremity  261  and defines the lowermost part of handle  260 .  
         [0044]     As best seen in  FIG. 3 , framework  251  supports a channel  275 , which passes therethrough and is perpendicular to handle  260  as illustrated. Arm  270  is disposed within and extends through channel  275  and is capable of reciprocal movement therein, in opposition to female engagement element  253 .  
         [0045]     Framework  251  further supports a friction device  274  located at forward extremity  261 , inferior to top surface  259 . The friction device is cylindrical and carries a flat proximal end  279 , and a concave distal end  278 . The proximal end carries medial and lateral shoulders,  279  A and B. A pair of threaded bores,  267 A and B extends horizontally into framework  251  commencing at a forward extremity  261  of the handled framework. The bores are positioned at the medial and lateral margins of friction device  274 , which permits the heads of screws  268 A and  268 B to overlap shoulders  279 A and  279 B. It can be seen that by adjustments of the screws, the friction device  278  can be moved relative to arm  270 . Such movement governs the degree of friction between the device and the arm. The friction device is not considered essential to successful function of the tool.  
         [0046]     Handled framework  251  further carries a needle guide  255 , moveably mounted to the perpendicular extension  263 . The device functions to support and precisely guide a surgical needle  252 , to its target, a female engagement element,  254 . The needle guide is horseshoe shaped, with its outer aspect defining a convex curve anteriorly, while limbs extend posteriorly like a horseshoe. A Bridge  2134 , connects the posterior limbs using four screws  135 A, B, C and D. With the bridge in place, four walls define an interior rectangular space,  2139 . Refer to FIGS.  5 and  5 A. The outer surfaces of perpendicular extension  263  oppose the inner surfaces,  2139 A,B,C and D of space  2139 , allowing the needle guide to slide relative to the perpendicular extension. A manual force is required to impart movement to the needle guide.  
         [0047]     At its anterior midline, the device is penetrated by two concentric holes which align with needle  252 . Superiorly a larger hole,  2136  penetrates the majority of the way through the device and fits arm  70 . Inferiorly a concentric smaller hole,  2137  completes the passage and fits needle  252  at its larger shank  2150 .  
         [0048]     Framework  251  further supports a space  285  bounded anteriorly by arm  270 , superiorly by handle  260 , inferiorly by uppermost part of extension  263  and laterally on one side by a continuous extension of handle  260 . On the opposing lateral side, a flat, removable plate,  257  is attached by screws,  2109 A,B and C. Posteriorly the space is open to accommodate lever  281 . The space houses the following parts: lever  281  with a pivot pin  292  and a spring  293 , pawl  282  with a pivot pin  2102  and a spring  2105  and arm  270  with inclined teeth  283 .  
         [0049]     Handled framework may be constructed of various materials, including so called engineered plastics, capable of withstanding autoclave temperatures and meeting FDA approval. Plastics may be molded or machined. Metals of choice include surgical stainless steel, titanium or other appropriate alloys. Of course, a combination of materials may be used.  
         [0050]     A second preferred embodiment of needle guide  255  is presented and labeled  256 . Please refer to  FIGS. 9 and 9 A. The device utilizes a piston and cylinder arrangement, wherein a cylinder  2162 , is created in distal end of arm  270 , parallel to the long axis of arm  270 . The cylinder  2162 , carries a piston  2163 . Piston  2163  carries a needle bore,  2169  passing through its long axis. A compression spring  2165 , is positioned between proximal end of piston  2163  and blind end  2170 , of cylinder  2162 . Piston  2163  carries a groove  2167 , on its outer surface. Groove  2167  parallels the long axis of piston  2163 , and it terminates short of the proximal and distal ends of the piston, thus creating abutments  2166 A and  2166 B. Distal arm  270  carries a threaded bore  2159 , supporting a set screw  2168 , which intercepts channel  2167 . With set screw  2168  positioned in groove  2167 , piston  2163  can move along groove  2167 , but its most distal position is defined by the contact of set screw  2168  and abutment  2166 B. Compression spring  2165  functions to keep piston  2163  in this most distal position at rest.  
         [0051]     A functional description follows. A straight surgical needle  252 , is inserted into needle bore  2169 . The proximal end  2152  of the needle abuts the blind end  2170  of cylinder  2162 . The apparatus is positioned in relation to the sternum. A force in applied to lever  281  as needed, thus moving the needled end  2153  of needle  252  to penetrate the sternum  2160 . Upon further penetration, the collar  2164 , of piston  2163 , contacts the upper surface of the sternum exerting a force on piston  2163 , forcing it ever deeper into cylinder  2162 . All the while however, as needle  252  continues its penetration, it is being supported by piston  2163 , the collar  2164 , of which remains in contact with the sternum.  
         [0052]     The arm is an elongate rigid device with opposing proximal end  271  and distal end  272 . Proximal end  271  carries a handle,  273 . Handle  273  may be used to impart two separate types of motion to arm  270 . By twisting the handle, a rotary motion is imparted to arm  270 , which serves to disengage the inclined teeth  283 , from pawl  282 . By pushing or pulling on the handle, up or down, linear motion is imparted, allowing arm  270  to be positioned as needed.  
         [0053]     A second preferred embodiment for arm  270  is a mechanism for securing needle  252  in blind bore  276 . A set screw  2108 , passing through a threaded bore  2109  intercepts needle  252 , locking the needle in position. Please refer to  FIG. 4A . After male engagement element  252 , and female engagement element  253  become secured, handle  273  can be used to extract suture  252  from the sternum.  
         [heading-0054]     The foregoing modification to arm  270  is applicable only when the apparatus utilizes the preferred embodiment of the needle guide  255 .  
         [0055]     However, the same end may be accomplished when the apparatus utilizes alternative embodiment  256  of needle guide. In this case, a set screw  2172  intercepts channel  2169  and needle  252  to accomplish the same goal.  
         [0056]     Framework  251  carries an attached drive assembly  280  ( refer to  FIGS. 1,2  and  3 ) that is capable of imparting motion to arm  270 , thus moving a male engagement element,  252  toward a female engagement element  254 , resulting in an interaction which will be described in detail later. Drive assembly  280  is a rachet arrangement which includes a lever,  281  pivoted to framework  251 , a pawl,  282  pivoted to lever  281  and inclined teeth,  283  carried by arm  270 . Lever  281  is pivoted to framework  251 , underlies handle  260  and is substantially coextensive with handle  260 . Referring to  FIG. 3 , lever  281  is elongate and has a proximal end,  290  disposed toward forward extremity  261  and a distal end,  291  disposed toward rearward extremity  262 . Proximal end,  290  extends in to framework  251 , more specifically into a chamber,  286  of framework  251  that communicates with channel  275  as illustrated.  
         [0057]     Lever  281  is pivoted between its proximal and distal ends,  290  and  291  as illustrated, by a pin,  292  attached to framework  251 . The pivot point of lever  281  is close to its proximal end,  290 . A spring,  293  encircles pin  292 . The spring has opposing free ends,  293 A and  293 B. These interact with opposing portions of handle  260  and lever  281 , thus biasing distal end,  291  of lever  281  away from rearward extremity,  262  of handle  260 . At the same time, end  290  of lever  281  and pawl  282  are biased toward handle  260  and away from distal extremity  264 . Those having regard for the art will readily appreciate that other spring forms or biasing arrangements can be used for introducing the described bias to lever  281 .  
         [0058]     As previously mentioned, pawl  282  is pivoted to proximal end,  290  of lever  281 . Arm  270  carries inclined teeth,  283 . The teeth are disposed at spaced intervals along one side of the arm intermediate to ends  271  and  272 . With reference to  FIG. 8 , pawl  282  has opposing ends,  2100  and  2101  plus a tongue,  282 A disposed proximal to end  2101 . End  2100  is pivoted to a pin,  2102  attached to proximal end,  290 .of lever  281 . Pawl  282  resides partially in a bifurcate feature,  2103  of lever  281 , which characterizes proximal end,  290 . Tongue  282 A confronts and interacts with teeth  283 . A spring,  2105  encircles pin  2102  and has opposing free ends,  105 A and B. These interact with confronting portions of pawl  282  and lever  281 , biasing pawl  282  toward teeth  283  and causing tongue,  282 A to interact with teeth,  283 . Spring  2105  maintains pawl  282  in a biased state against arm  270 . Those having regard for the art will readily appreciate that other spring forms or biasing arrangements can be used for introducing the described bias to pawl  282 .  
         [0059]     Handle  260  and lever  281  are capable of being taken up by hand. By applying a manual force to lever  281 , the bias of spring  293  is overcome and lever  281  is pivoted. This causes pawl  282  to reciprocate and interact with teeth  283  which forcibly moves arm  270  and engagement element  252  toward engagement element  253 . When the manual force on lever  281  is released, spring  293  pivots lever  281  to an open position. That is to say, distal end  291  of the lever moves away from distal end  262  of the handle  260 . At the same time pawl  282  moves upward (away from distal extremity  264 ) and out of engagement with a single tooth  283 , and into engagement with a second single tooth located higher on arm  270 . The second tooth is higher than the first on arm  270 . By repeatedly squeezing and releasing the lever: handle combination, the pawl is repeatedly engaged and disengaged. Arm  270 , therefore is moved downward in channel  275  (toward distal extremity  264 ). This, of course moves the engagement elements,  252  and  254  closer and closer together. Ordinarily, two or three strokes will engage the elements. Construction materials and methods are unchanged from those previously suggested.  
         [0060]     Details of the male engagement element  252  and the female engagement element  254  will now be considered. Refer to  FIGS. 2, 3  and  8 . Engagement element  252  is a surgical needle carried by arm  270  in blind bore  276 . Alternately, when second preferred embodiment  256  is employed, needle  252  is then carried in bore  2169  in piston  2163 . Needle  252  has a proximal, butt end  2152  and a distal penetrating end  2153 . The needle has a longer and thicker proximal shank,  2150  and a shorter and thinner distal shank,  2151 . This arrangement discourages needle failure by buckling or compression, while the size of the distal needle and female engagement element may be minimized. Penetrating end  2153  of the needle is elliptical rather than sharp. The female engagement element,  254  is a cylinder attached to a stainless steel surgical suture,  2154 . Attachment of the suture to the cylinder may be accomplished with surgical adhesives, crimping or alternate methods. Inside diameter of the cylinder must be sized to accommodate distal end  2151  of needle  252  to extremely close tolerances.  
         [0061]     fixture  253  is a housing to precisely position and secure the female engagement element  254  in a socket  2113 . Socket  2113  has an upper, proximal end  2118 , and a lower, distal end  2119 . The socket is a cylindrical passage. It narrows abruptly at its distal end, creating a small gap  2104 . The gap allows a suture  2154 , which is attached to the female engagement element to pass there through, but blocks the female engagement element. The narrowed site provides a seat for the female engagement element.  
         [0062]     Fixture  253  includes two separate pieces. Please refer to  FIGS. 7, 7A  and  7 B. A larger “L” shaped piece  2120  and a smaller rectangular piece  2120  A. The pieces, when joined together, form a rectangular block. The pieces interact and join at two interfaces. An opposing face  2114  of piece  2120  interfaces with opposing face  2115  of piece  2120 A. This forms a plane of opposition oriented in a fore and aft direction. The plane exactly bisects socket  2113 . A second interface is oriented at right angles to the first. The second interface is formed by opposing face  2122  of piece  2120 A and opposing face  2123  of lateral extension,  2124  of piece  2120 . Piece  2120  is fixed in position by two parallel pins  2110  and  2110 A and screw  2109 . Piece  2120  is thus secured to seat  265  of the handled framework  251 . Piece  2120 A is capable of medial and lateral (side to side) movement. Such movement permits socket  2113  to assume a wider disposition, assuring easy disengagement of the suture and female engagement element from the apparatus.  
         [0063]     The mechanism by which such movement is generated will now be described. Movement of piece  2120 A toward or away from piece  2120  occurs along a pair of guide pins,  2174 A and B. A pair of bores  2173 A and B traverse piece  2120 A and the penetrate a short distance into piece  2120 . The guide pins are stationarily secured in the bores in piece  2120 . The guide pins slideably fit into the bores in piece  2120 A. This arrangement allows movement of piece  2120 A relative to piece  2120 , which is fixed to the handled framework. A channel,  2125  traverses both piece  2120 A and piece  2120 . Its proximal portion, traversing piece  2120 A is threaded, while its distal portion, traversing piece  2120  is not. A shaft  2125 A traverses both portions of the channel and is threaded in its proximal portion to coact with the threads of the proximal channel. The shaft carries a knob  2111  at its threaded end to impart rotation to the shaft.  
         [0064]     When a manual force is used to impart a rotary motion to knob  2111 , shaft  2125 A is rotated and a linear motion is created which moves piece  2120 A toward or away from piece  2120 , thus opening or closing socket  2113 . Opening the socket permits the apparatus to be easily disengaged from the suture. Those familiar with the art will recognize other methods are available to accomplish the ends described, such as springs, hinges or manual manipulation to name a few.  
         [0065]     The close tolerances required for proper finction of fixture  253  seem to make the metal alloys the materials of choice and machining the preferred method for construction. Molding of appropriate plastics might be possible.  
         [0066]     Needles are produced using surgical stainless steel rods of appropriate diameter. The needle tips require precise sizing, therefore some machining is required. This can be accomplished using CNC mini lathes. Grinding is also an alternative. Forging methods with supplemental machining is also possible.  
         [0067]     A word regarding the method for joining the suture to the female engagement element is necessary. Crimping is possible, but may cause deformity to the engagement element, which may interfere with proper fit in the socket. Epoxy resins work well, but if they are used, must be medical adhesives, biocompatible, USP class 6. A heat curable epoxy, Permabond 4E96 meets these criteria and is available from Permabond of Bridgewater, N.J.