Patent Publication Number: US-10786246-B2

Title: Swaging systems for attaching surgical needles to sutures and testing attachment strengths

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present patent application is a continuation of U.S. Patent Application Ser. No. 15/465,912, filed Mar. 22, 2017, now U.S. Pat. No. 10,448,947, the disclosure of which is hereby incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present patent application is generally related to swaging systems for attaching surgical needles to sutures, and is more particularly related to systems, devices and methods for testing the strength of needle and suture attachments. 
     Description of the Related Art 
     Armed surgical needles, i.e., needles having sutures attached to one end thereof, are typically manufactured utilizing manual, semi-automated, and fully automated procedures that feed a length of suture material into a suture receiving opening of a surgical needle, and that swage (i.e., compress) the surgical needle to the end of the suture. 
     Swaging needles to sutures typically involves inserting the free end of a suture into an axial bore of a needle barrel of a surgical needle, and holding the suture inside the axial bore while a swage die impinges upon the outer surface of the needle barrel, thereby compressing a portion of the bore onto the suture. The compressed portion of the axial bore grasps the suture by mechanical interference and by surface friction. The swaging process is conducted to create an attachment between the needle barrel and the suture that meets or exceeds “pull-out” strength standards. 
       FIG. 1  illustrates a prior art method of swaging a needle N to a suture S utilizing a single-sided, multiple indentation swaging protocol. The suture S is inserted into a suture receptacle SR of the needle N, and at least one stake point of a die is driven into one side of the needle N to deform the wall W of the needle and create a depression D 1  that causes the wall W to impinge upon the suture S, creating a pressure point P 1  between the depression D 1  and the opposing portion of the needle wall W. One or more additional indentations D 2  can be made to create additional pressure points, e.g. P 2 . The suture S is retained in the needle N by virtue of the impingement of a small portion of the needle wall W on a correspondingly limited area of the suture S. 
       FIG. 2  illustrates another prior art method of swaging a needle N to a suture S utilizing a double-sided, aligned swaging protocol. The suture S is inserted within a suture receptacle SR of a needle N, and two opposing stakes are utilized to create aligned depressions D 3 , D 4  that form a pressure point P 3  between the two depressions, D 3 , D 4  for grasping the suture S. The focused pressure at P 3  may create sheer stress that could result in fracturing of the suture S, leading to suture detachment. To avoid exceeding the sheer stress limits of the suture material, the dimensions of the suture receptacle SR, the thickness and deformability of the wall W of the needle N, and the depression depth of the depressions D 3  and D 4  are controlled. 
       FIG. 3  shows a prior art needle swaging assembly  20  with first and second swage dies  22 A,  22 B converging to hold a needle N for swaging. The needle N is gripped between needle holders  24 A,  24 B and abuts against needle stops  26 A,  26 B with the suture receptacle SR aligned with the suture grooves  28 A,  28 B. Insertion of the needle N between the needle holders  24 A,  24 B is facilitated by needle funnel portions  30 A,  30 B. A suture funnel  32  aides in threading the suture S through the suture grooves  28 A,  28 B and into the suture receptacle SR of the needle N. Swaging elements  34 A,  34 B are free to slide within respective slots  36 A,  36 B so that the stakes  38 A,  38 B thereof can impinge upon the needle N. In the embodiment shown in  FIG. 3 , the stakes  38 A are laterally offset relative to the stakes  38 B such that when the swaging elements  34 A,  34 B are urged together during the swaging operation, the needle N will be swaged to create a serpentine configuration in the suture receptacle SR. A greater or lesser number of stakes  38 A,  38 B may be utilized, ranging from one stake  38 A,  38 B on each swaging element  34 A,  34 B, up to any selected number of stakes  38 A,  38 B. The height, spacing and shape of the stakes  38 A,  38 B, as well as the relative lateral offset of the stakes  38 A,  38 B on opposite swaging elements  34 A,  34 B may be selected to adjust swaging and suture attachment strength. 
     One approach to providing good suture attachment is multiple hit swaging, wherein a needle is subjected to swaging of a controlled depth, however, the compression is distributed over a large area of the needle barrel (e.g., around the circumference of the needle barrel). To achieve this type of swaging, the needle may be rotated relative to the swaging dies between multiple swaging compressions. In this manner, multiple angularly offset swaging operations are performed to attach a single needle to a single suture. While this approach provides a reliable attachment, each hit on the barrel of the needle produces stress in the needle barrel and the suture. The needle and suture materials have some degree of malleability, but when the limit of malleability is reached, the materials will fail, leading to, in the case of the needle, cracking and loss of attachment, or breakage. Cracking is a particular problem when harder alloys are used, including advanced alloys such as 4310 SS, nickel-titanium SS, and 420 SS. Further, needle materials have some elasticity, such that the relief of residual stress causes the needle barrel to relax over time, leading to a loss of attachment between the needle bore and the suture. 
     One advance directed to minimize failure of the parts during a swaging operation is disclosed in commonly assigned U.S. Pat. No. 8,214,996 to Stametz et al., the disclosure of which is hereby incorporated by reference herein. In one embodiment, the &#39;996 patent discloses a method of attaching a suture to a needle barrel. In one embodiment, a first compression stroke compresses a radial top of a needle barrel against a suture that has been inserted into a bore of the needle barrel while restraining the radial bottom and radial sides of the needle barrel against deformation. A second compression stroke compresses the bottom of the barrel against the suture while restraining the sides against deformation. In another embodiment, the top and bottom sides of a needle barrel are compressed while the opposing lateral sides of the needle barrel are restrained against deformation. In one embodiment, an apparatus for attaching a suture to a needle barrel includes two die sets, each including a die with a groove therein. In one die set, the groove protects the bottom and lateral sides of the needle barrel from deformation while the top is compressed. In the other die set, the groove protects the lateral sides of the needle barrel from deformation while the bottom of the needle barrel is compressed. 
     After armed needles are formed, they must be tested to determine if they satisfy certain requirements demanded by surgeons. For example, U.S. Pat. No. 3,980,177 discloses a requirement of a surgeon or medical personnel to be able to detach an armed surgical needle from a suture after suturing to avoid the necessity of cutting the suture with scissors. The &#39;177 patent discloses a needle-suture combination having a straight pull-out value of between about three (3) ounces and 26 ounces depending upon the size of the suture. The &#39;177 patent, however, does not disclose a means for testing the armed surgical needle to determine its pull-out value, i.e., the force necessary to detach the needle from the suture. 
     A conventional method for testing a needle and suture attachment includes a step of manually pulling the suture to a minimum force level. This is typically done by the same operator following a swaging operation. To pull-test the needle-suture attachment, the operator is required to move the needle and suture from a swaging station to a separate pull testing fixture. There are various aspects of this methodology that are not optimal. First, the operator is required to remove the needle-suture assembly from the swaging apparatus and mount it to a pull test station, which takes time. Second, the additional handling of the needle-suture assembly increases the opportunity for the suture to be damaged. Third, the integrity of the needle-suture assembly can be compromised if the suture is pulled for too long (i.e., the suture may start to creep out of the needle receiving hole), which can result in weakened attachment strength. 
     In spite of the above advances, there remains a need for improved swaging systems that make and test armed surgical needles in more efficient, effective, and reliable manners. In addition, there remains a need for improved manual swaging systems for using fine needles and suture for making armed surgical needles for delicate surgical procedures. There also remains a need for swaging systems that produce armed surgical needles whereby the integrity of the needle and suture attachment meets minimum strength requirements in a consistent and efficient manner. 
     SUMMARY OF THE INVENTION 
     In one embodiment, a combined needle swaging and testing system preferably includes a swaging press having a die that may be used for both swaging a needle (i.e., attaching a needle to the end of a suture), and conducting a pull test on the armed surgical needle to assess the needle and suture attachment. 
     In one embodiment, the combined needle swaging and testing system desirably includes a control system that generates both visual and audible cues to an operator of the swage press during the testing to ensure that the needle and suture attachment is not severely overstressed or held at a high force for an extended period of time that could cause undetected damage to the needle and suture attachment. 
     In one embodiment, a swage press preferably includes upper and lower presses having respective upper and lower die that are used for a swaging process. In one embodiment, the lower die preferably includes a hinge mechanism disposed within the lower press that is placed horizontally in the lower press and that is orthogonal to the direction of swaging. The hinge mechanism preferably has a bottom plate that is secured on the lower die, which, in turn, is mounted on the frame of the swaging system. The hinge mechanism preferably includes a top plate that is designed and configured to receive the swage tooling. The bottom and top plates are preferably connected on one side with a precision ground rod to form a hinge and the other side of the bottom plate desirably contains a recess that is configured to accommodate a load cell. In one embodiment, during a swaging event, the hinge mechanism holds the bottom plate in place, however, after the swaging event, it serves to measure the pull force applied to a needle and suture attachment, as described herein. 
     In one embodiment, the swaging tooling that is connected to the top plate of the hinged mechanism desirably has an additional “testing” notch that is larger than the suture diameter, but smaller than the needle diameter. As such, after swaging a needle to a suture, the suture and attached needle may be moved a very small distance away from the location of the swage notch (e.g., 1 mm or less) to nest in the testing notch, and then that suture is pulled until the proximal end of the needle catches in the relatively smaller width testing notch. Since the entire apparatus is connected through a hinge, as the suture is pulled, the weight of the top plate of the hinged mechanism that is translated through the load cell is lessened. This decreasing force (i.e., removal of weight from the load cell) is monitored at a rate of several thousand times per second through a microprocessor that receives load signals from the load cell. 
     In one embodiment, the output pins of a microprocessor are connected to a light emitting element, such as a red-green-blue (RGB) light emitting diode that can be viewed directly through the stereoscope used by the swaging operator, thus preventing the need for the operator to move his or her head and look away from the work at hand, which minimizes operator fatigue and optimizes output. In one embodiment, other microprocessor output pins may be connected to a buzzer or chime to provide audible signals to the operator. In one embodiment, an operator will receive both visual and auditory signals during the pull test that help the operator to ensure that the proper prescribed force and time duration of the pull test are achieved. 
     In one preferred embodiment, for an armed surgical needle having a 7-0 suture, the microprocessor will desirably send a green light signal to the operator when a force drop equivalent to &gt;95 grams is detected by the load cell. If a force of between 95 and 115 grams is maintained for a minimum of 0.2 s, then the microprocessor will send signals to turn the light blue and a triple beep will be provided by the buzzer. The operator must then release the force on the suture before the triple beep ceases (at 0.6 s). If the pull force at any time exceeds 115 grams, or if the operator pulls the suture continuously for more than about 0.6 s, then the RGB LED will turn red and a continuous, annoying audible signal will be generated from the buzzer signaling the operator to discard the sample he or she just tested. 
     In one embodiment, the swaging system disclosed herein blends the capabilities of humans with the capabilities of high speed processors to greatly improve the control, efficiency and reliability of pull tests. 
     In one embodiment, a system for attaching a needle to a suture preferably includes a top swaging die, a frame, an arm pivotally mounted to the frame, the arm having a proximal end and a distal end, a bottom swaging die mounted on top of the arm, a top swaging die moveably mounted to the frame and aligned with the bottom swaging die, and a load cell mounted to the frame and in contact with the distal end of the arm. 
     In one embodiment, a method of swaging and pull testing a suture attached to a needle desirably includes swaging a needle to a suture using the above-described system, positioning the armed surgical needle into a testing notch, pulling the suture, and sensing a force change due to pulling the suture. 
     In one embodiment, the lower swage die preferably includes a testing notch that has an opening larger than the suture diameter but less than that of the swaged needle. 
     In one embodiment, the needle is left in the lower die after swaging and the suture is pulled perpendicular to the swage die. 
     In one embodiment, the load cell communicates with a microprocessor. 
     In one embodiment, the arm rests on the load cell. In one embodiment, the load cell rests on the arm. 
     In one embodiment, the swaging press may have a foot pedal to interrupt power to the load cell when the pedal is pressed and restore power after a pre-defined period of time following swaging (e.g., 500 ms). 
     In one embodiment, the swaging system may include audible and/or visual indicators. In one embodiment, the indicator(s) are activated when a change in force (as measured by the load cell) reaches one or more predetermined force levels and/or time periods. 
     In one embodiment, the visual and audible indicator(s) exhibit different indications (e.g., colors, sounds, vibrations, etc.) based on predetermined force levels and/or time periods. 
     In one embodiment, the system may include a feedback mechanism designed to increase the force or displacement of swaging during the next swaging event should a needle-suture attachment fail during testing. 
     In one embodiment, the swaging system may be entirely or partly automated. 
     In one embodiment, a swaging system for attaching surgical needles to sutures and testing the attachment strength desirably includes a frame, a bottom swaging die mounted on the frame, and a top swaging die mounted on the frame. In one embodiment, the top swaging die is moveable up and down along a swaging axis that is in alignment with the bottom swaging die. In one embodiment, the bottom swaging die includes a hinge mechanism with a bottom plate mounted to the frame and a top plate overlying the bottom plate. In one embodiment, the top and bottom plates are pivotally connected to one another for enabling the top plate to pivot relative to the bottom plate. The bottom swaging die preferably includes a swaging tool mounted on the top plate that extends toward the top swaging die along the swaging axis. In one embodiment, the system includes a load cell disposed between the top and bottom plates for monitoring the load on the top plate. 
     In one embodiment, the swaging tool desirably includes an upper end having a top surface with a swaging notch for swaging a needle to a suture to form an armed surgical needle, and a testing notch, adjacent the swaging notch, for conducting a pull test on the armed surgical needle. In one embodiment, the swaging and testing notches may extend along respective longitudinal axes that are orthogonal to the swaging axis. In one embodiment, the swaging and testing notches preferably extend along respective longitudinal axes that are parallel with the top surface of the top plate and perpendicular to the swaging axis. 
     In one embodiment, the swaging notch desirably has a first width and the testing notch has a second width that is smaller than the first width. In one embodiment, a needle components of an armed surgical needle has a diameter that is less than or equal to the first width of the swaging notch and greater than the second width of the testing notch, and the suture component of an armed surgical needle has a diameter that is less than the first width of the swaging notch and the second width of the testing notch. In one embodiment, the first width of the swaging notch is about 8 mil, the second width of the testing notch is about 4 mil, the diameter of the needle is about 7.5-7.8 mil, and the diameter of the suture is about 3.5 mil. 
     In one embodiment, the swaging system preferably includes a control system having at least one microprocessor in communication with the load cell for receiving load signals measured by the load cell. The microprocessor is preferably adapted for detecting changes in the load signals measured by the load cell. 
     In one embodiment, the control system desirably includes one or more pull test programs stored therein for conducting pull tests on armed surgical needles. Each pull test program desirably has an acceptable load range having predetermined lower and upper load limits, and an acceptable time range having predetermined lower and upper time limits for the length of a load test. 
     In one embodiment, a pull test program enables a human to commence a pull test inspection when a load change is detected by the microprocessor. In one embodiment, a pull test program indicates that the tested armed surgical needle is acceptable if the detected load change is between the predetermined lower and upper load limits and the detected time is between the predetermined lower and upper time limits. In one embodiment, the pull test program indicates that the tested armed surgical needle is unacceptable if the detected load change is above the predetermined upper load limit. In one embodiment, the pull test program indicates that the tested armed surgical needle is unacceptable if the detected load change is between the predetermined lower and upper load limits and the detected time is above the predetermined upper time limit. 
     In one embodiment, during a pull test inspection of an armed surgical needle, the control system preferably generates visible or audible signals that indicate whether the tested armed surgical needle is acceptable or unacceptable. In one embodiment, the control system generates visible green light and an audible beep if the tested armed surgical needle is acceptable and visible red light and an audible buzzer if the tested armed surgical needle is unacceptable. 
     In one embodiment, a swaging system for attaching surgical needles to sutures and testing the attachment strength of armed surgical needles preferably includes a frame, a bottom swaging die mounted on the frame, and a top swaging die mounted on the frame and being moveable up and down along a swaging axis that is in alignment with the bottom swaging die. 
     In one embodiment, the bottom swaging die desirably has a hinge mechanism including a bottom plate mounted to the frame, a top plate overlying the bottom plate, whereby the top and bottom plates are pivotally connected to one another for enabling the top plate to pivot relative to the bottom plate, and a swaging tool mounted on the top plate that extends toward the top swaging die along the swaging axis, the swaging tool includes an upper end having a top surface with a swaging notch for swaging a needle to a suture to form an armed surgical needle, and a testing notch, adjacent the swaging notch, for conducting a pull test on the armed surgical needle. In one embodiment, the hinge mechanism preferably includes a load cell disposed between the top and bottom plates for monitoring the load on the top plate. 
     In one embodiment, the swaging system desirably has a control system with at least one microprocessor in communication with the load cell for receiving load signals generated by the load cell and detecting changes in the load signals. In one embodiment, the control system desirably has one or more pull test programs stored therein for conducting pull tests on armed surgical needles. In one embodiment, each pull test program preferably includes an acceptable load range having predetermined lower and upper load limits, and an acceptable time range having predetermined lower and upper time limits. 
     In one embodiment, the pull test program enables commencement of a pull test inspection when a load change is detected by at least one microprocessor. In one embodiment, a pull test program indicates that the tested armed surgical needle is acceptable if the detected load change is between the predetermined lower and upper load limits and the detected time is between the predetermined lower and upper time limits. In one embodiment, a pull test program indicates that the tested armed surgical needle is unacceptable if the detected load change is above the predetermined upper load limit. In one embodiment, a pull test program indicates that the tested armed surgical needle is unacceptable if the detected load change is between the predetermined lower and upper load limits and the detected time is above the predetermined upper time limit. 
     In one embodiment, during a pull test inspection of an armed surgical needle, the control system is configured to generate visible or audible signals that indicate whether the tested armed surgical needle is acceptable or unacceptable. In one embodiment, the control system generates visible green light and a first audible sound if the tested armed surgical needle is acceptable and visible red light and a second audible sound, different from the first audible sound, if the tested armed surgical needle is unacceptable. 
     In one embodiment, a stereoscope is mounted on the frame for viewing the swaging and inspection notches at the top surface of the swaging tool. In one embodiment, the stereoscope desirably has at least one light emitting diode for generating visible light, such as green visible light and red visible light for indicating the status of the attachment test. 
     In one embodiment, the hinge mechanism preferably includes a pin interconnecting adjacent sides of the top and bottom plates for pivotally connecting the top and bottom plates. In one embodiment, the bottom plate preferably has a guard located on a side of the bottom plate that is opposite the pin. In one embodiment, the guard has an upper end that extends above the top surface of the top plate for preventing an operator from inadvertently contacting the top surface of the top plate. 
     In one embodiment, the bottom plate of the hinge mechanism has a recess and the load cell is disposed within the recess. In one embodiment, the load cell has an adjustable set screw projecting from an upper end of the load cell, and the top plate has a set screw opening accessible at the top surface of the top plate for accessing the set screw of the load cell. 
     In one embodiment, a swaging system for attaching surgical needles to sutures and testing the attachment strength desirably includes a frame, a bottom swaging die mounted on the frame, and a top swaging die mounted on the frame and being moveable up and down along a swaging axis that is in alignment with the bottom swaging die. 
     In one embodiment, the bottom swaging die preferably has a hinge mechanism including a bottom plate mounted to the frame, a top plate overlying the bottom plate, whereby the top and bottom plates are pivotally connected to one another for enabling the top plate to pivot relative to the bottom plate, and a swaging tool mounted on the top plate that extends toward the top swaging die along the swaging axis. In one embodiment, the swaging tool desirably has an upper end having a top surface with a swaging notch accessible at the top surface for swaging a needle to a suture to form an armed surgical needle, and a testing notch accessible at the top surface, adjacent the swaging notch, for conducting a pull test on the armed surgical needle. In one embodiment, the swaging and testing notches preferably extend along respective longitudinal axes that are orthogonal to the swaging axis. In one embodiment, a load cell is preferably disposed between the top and bottom plates for monitoring the load on the top plate. 
     These and other preferred embodiments of the present invention will be described in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a conventional method of swaging a needle to a suture. 
         FIG. 2  shows a second conventional method of swaging a suture to a needle. 
         FIG. 3  shows a prior art needle swaging assembly having first and second swage dies that converge to attach a needle to a suture. 
         FIG. 4  shows an armed surgical needle including a needle and a suture, in accordance with one embodiment of the present patent application. 
         FIGS. 5A-5C  show a swaging system for attaching surgical needles to sutures, in accordance with one embodiment of the present patent application. 
         FIG. 6A  shows a perspective view of a hinged assembly of a lower swage die, in accordance with one embodiment of the present patent application. 
         FIG. 6B  shows a side elevation view of the hinged assembly shown in  FIG. 6A . 
         FIG. 7  shows a partial cross sectional view of the hinged assembly shown in  FIG. 6B  including a swaging tool, and a load cell disposed between top and bottom plates of the hinged assembly. 
         FIGS. 8A and 8B  show an upper end of the swaging tool shown in  FIG. 7  including a swaging notch and a testing notch, in accordance with one embodiment of the present patent application. 
         FIGS. 9A-9E  show a method of testing an armed surgical needle using the swage tool shown in  FIGS. 7, 8A, and 8B , in accordance with one embodiment of the present patent application. 
         FIG. 10  shows a hinged assembly of a lower die of a swaging system, in accordance with one embodiment of the present patent application. 
         FIG. 11  shows a flow chart upon which a computer operated program is based for swaging and inspecting an armed surgical needle, in accordance with one embodiment of the present patent application. 
         FIGS. 12A and 12B  are graphs plotting data to indicate that the lower end of the attachment force population has been eliminated, in accordance with one embodiment of the present patent application. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIG. 4 , in one embodiment, an armed surgical needle  100  preferably includes a surgical needle  102  that is secured to the end of a suture  104 . In one embodiment, the needle  102  is made of a broad variety of rugged materials including metal alloys such as stainless steel, 4310 SS, nickel-titanium (NiTi) SS and 420 SS, or advanced alloys, such as, tungsten-rhenium (W—Re) alloys or similar refractory alloys. In one embodiment, the needle  102  is made of a tungsten-rhenium alloy that is sold under the trademark EVERPOINT® by Ethicon, Inc. of Somerville, N.J. 
     In one embodiment the suture material may be made of conventional, biocompatible, absorbable materials, non-absorbable materials, and combinations of absorbable and non-absorbable materials. Preferred non-absorbable materials include polypropylene, a polymer blend of polyvinylidene fluoride and polyvinylidene fluoride-co-hexafluoropropylene, polyethylene, polyvinylidene fluoride (PVDF), polyesters, polyethylene terephthalate, glycol-modified polyethylene terephthalate, polytetrafluoroethylene, fluoropolymers, nylons etc. and the like, or copolymers of combinations thereof. Preferred absorbable polymeric materials include polydioxanone, polyglactin, polyglycolic acid, copolymers of glycolide and lactide, polyoxaesters, and poliglecaprone. In certain preferred embodiments, the suture material may include combinations of both absorbable and non-absorbable materials. In addition, metals may be suitable for certain applications, such as instances where specific strength, electrical conductivity, or corrosion resistance is necessary. In one preferred embodiment, the suture material preferably includes a polymer blend of polyvinylidene fluoride and polyvinylidene fluoride-co-hexafluoropropylene material. In addition, any of these materials may have conventional surface modifications that include coatings, plasma treatments, therapeutics, and the like. In one embodiment, the needle  102  is coated with a silicon coating. In one embodiment, the suture  104  is a polypropylene suture sold under the trademark PROLENE® by Ethicon, Inc of Somerville, N.J. 
     Referring to  FIGS. 5A-5C , in one embodiment, a swaging press  120  for making armed surgical needles preferably includes a frame  122  having a bottom die holder block  124  with a bottom swaging die  125  mounted thereon, and a top die block holder  128  having a top swaging die  129  that is adapted to move up and down along a swaging axis A 1  that is aligned with the bottom swaging die  125 . In one embodiment, the top swaging die  129  is mounted on a precision slide  135  that is configured to slide up and down on the frame  122 . The swaging press  120  desirably includes a servomotor  130  that is activated for moving the precision slide  135 , the top die block holder  128 , and the top swaging die  129  up and down along the swaging axis A 1  relative to the bottom swaging die  125 . The swaging press system  120  preferably includes a power connection  132  for the servomotor  130 . The power connection  132  may house an encoder that provides position feedback information for the top swaging die  129 . 
     In one embodiment, the swaging system  120  preferably includes a human machine interface (HMI)  134  that is connected to and/or positioned adjacent the frame  122 . In one embodiment, the HMI  134  desirably has an LCD display  136  that enables an operator to interface with the HMI  134  for selecting a particular swaging program and/or monitoring a swaging and testing operation. In one embodiment, the HMI  134  preferably includes a control system having one or more microprocessors, memory devices, and programs for operating the swaging system  120 . In one embodiment, the microprocessor contained within the HMI  134  desirably has numerous programs and/or subroutines loaded therein that may be selected by an operator so that the swaging system  120  may be utilized for making a wide range of armed surgical needles having needles with a range of different sizes and suture material having a range of different sizes. 
     In one embodiment, the swaging system  120  desirably includes a stereoscope  138  that is mounted to the frame  122 . The stereoscope  138  is preferably aimed at the lower die  125  for using during swaging and testing operations, as will be described in more detail herein. The stereoscope  138  desirably includes optics that provide for a magnified view of the needles, suture material, and opposing dies during swaging and testing operations. In one embodiment, the stereoscope  138  may include tightening knobs  140  adjusting and locking the position of the stereoscope optics relative to the opposing dies, and the swaging and testing locations on the dies, and magnification adjustment knobs for adjusting magnification levels. 
     In one embodiment, the stereoscope  138  may include one or more light generating elements, such as red-green-blue (RGB) light emitting diodes, that may be viewed directly through the stereoscope used by the swaging operator, thus eliminating the need for the operator to move his or her head and look away from the work at hand. In one embodiment, the RGB diode is desirably mounted on either the top or bottom die holder blocks within the field of view of the stereoscope. This benefit is related to minimizing operator fatigue and optimizing output. In one embodiment, microprocessor output pins are connected to an audible signal generator, such as a beeper or buzzer, to provide audible signals or sounds for an operator of the swaging system. As such, an operator may receive both visual and auditory signals during testing that help the operator to insure that the proper prescribed force and duration of pull tests have been achieved. 
     In one embodiment, the red-green-blue light emitting diodes within the stereoscope  138  are in communication with the control system within the HMI  134  ( FIG. 5C ). 
     Referring to  FIGS. 6A and 6B , in one embodiment, the swaging system preferably includes a hinge mechanism  150  that is coupled with the lower die  125  ( FIGS. 5A-5C ). In one embodiment, the hinge mechanism  150  is desirably placed horizontally in the lower die and orthogonal to the direction of the swaging axis A 1  ( FIGS. 5B, 5C and 6B ). In one embodiment, the hinge mechanism  150  desirably includes a bottom plate  152  and a top plate  154  that serves as a mounting platform for the lower swaging die and that overlies the bottom plate  152 . The hinge mechanism  150  preferably includes a hinge  156  that enables the top plate  154  to pivot about the hinge  156  relative to the bottom plate  152 . In one embodiment, the hinge mechanism  150  may include bearings or bushings in contact with the hinge  156  for minimizing friction as the top plate  154  pivots and moves relative to the bottom plate  152 . 
     In one embodiment, the hinge mechanism  150  preferably includes a guard  158  that is secured to an end of the bottom plate  152  or made integral with it on a side of the bottom plate that is opposite the hinge  156 . In one embodiment, the guard  158  has an upper end  160  that projects above a top surface  162  of the top plate  154  to prevent an operator from inadvertently bumping into and/or contacting the top half  154  thereby sending erroneous signals through the load cell to the microprocessor. 
     Referring to  FIG. 6B , in one embodiment, the hinge mechanism  150  preferably includes a swaging tool  125  or bottom swaging die projecting upwardly from the top surface  162  of the top plate  154 . In one embodiment, the swaging tool  125  desirably has an upper end  166  that is adapted to receive a needle  102  and a suture  104  for attaching the needle to the suture. In one embodiment, the upper end  166  of the swaging tool  125  has a first notch for swaging the needle  102  to the suture  104  (i.e., the swaging notch), and a second notch for inspecting the attachment of the needle  102  to the suture  104  (i.e., the inspection notch). 
     Referring to  FIG. 6A , in one embodiment, the top plate  154  of the hinge mechanism  124  desirably includes openings  168 A- 1680  that are utilized for securing a die support plate over the top surface  162  of the top plate  154  for providing support for the base of the swaging tool  125  projecting from the top surface of the top plate. In one embodiment, the top plate  154  also preferably includes a set-screw opening  170  formed in the top surface  162  of the top plate that provides access to a set screw on a load cell disposed within the bottom plate  152 , as will be described in more detail herein. 
     In one embodiment, the guard  158  desirably has an opening  172  formed therein that enables conductive elements, conductive conduits, and/or conductive leads to pass therethrough for interconnecting the load cell of the hinge mechanism with a microprocessor and/or system controller. 
     Referring to  FIG. 7 , in one embodiment, the hinge mechanism  150  preferably includes a load cell  174  disposed in the bottom plate  152  of the hinge mechanism, which, in turn, is mounted to the lower die holder block  124  or directly to the frame  122  of the press ( FIG. 5C ). The load cell  174  is preferably coupled with a conductive lead  176  that passes through the opening  172  ( FIG. 6A ) of the guard  158 . The conductive lead  176  is desirably interconnected with a microprocessor and/or a system controller for communicating with the load cell  174 . In one embodiment, the load cell  174  preferably has an adjustable set screw  178  that is in alignment with the set screw opening  170  ( FIG. 6A ) accessible at the top surface  162  of the top plate  154 . 
     In one embodiment, the load cell  174  is a transducer that is used to create an electrical signal whose magnitude is directly proportional to the force being measured. The load cell may be a piezoelectric cell, a strain gauge load cell and/or combinations thereof. 
     During a swaging process, the hinge mechanism  150  holds the swaging tool  125  in place, however, directly after swaging, the hinge mechanism is configured to measure the pull force exerted upon an armed surgical needle. In one embodiment, in addition to a swaging notch, the upper end  166  of the swaging tool  125  also has a testing notch adjacent the swaging notch that is larger than the diameter of the suture  104  but smaller than the diameter of the needle  102 . In this way, after swaging, the suture  104  may be moved a very small distance away from the swaging notch location (e.g. 1 millimeter or less) to the testing notch location. 
     For testing the armed surgical needle, the suture  104  is pulled in the direction designated A 2  in  FIG. 7  until the proximal end of the needle  102  catches the testing notch. Axis A 1  shows the swaging direction of motion and the direction of gravity. Axis A 2  shows the direction that the suture  104  is pulled when the suture (attached to the needle  102 ) is positioned within the testing notch and the proximal end of the needle  102  engages an end of the relatively smaller diameter testing notch. Since the top plate  154  is connected to the hinge mechanism  150  via the hinge  156 , as the suture  104  is pulled in the direction designated A 2 , the weight of the top plate  154  that is translated through the load cell  174  is lessened. This decreasing load (i.e. removal of weight from the load cell  174 ) is monitored at a rate of several thousand times per second through a microprocessor in the control system that receives the signals from the load cell. 
     Referring to  FIGS. 8A and 8B , in one embodiment, the swaging tool  125  preferably has an upper end  166  with a top surface  180  that is generally parallel with the top surface  162  of the top plate  154  of the hinge mechanism  150  ( FIG. 7 ). In one embodiment, the swaging tool preferably includes a swaging notch  182  that is adapted to receive a needle and a suture during a swaging operation, and an adjacent inspection notch  184  that is utilized for inspecting an armed surgical needle after the needle has been attached to an end of a suture. The swaging notch  182  and the inspection notch  184  desirably extend across the thickness T 1  of the top surface  180 . In one embodiment, the swaging notch  182  extends across the thickness of the swaging tool and has a width W 2  of about 8 mil, and the inspection notch  184  also extends across the thickness of the swaging tool and has a width W 3  of about 4 mil. In one embodiment, the distance between the swaging notch  182  and the testing notch  184 , designated D 5 , is preferably about 1 millimeter or less. 
     In one embodiment, the surgical needle  102  has an outer diameter of about 7.8 mil, which enables the needle to be positioned within the swaging notch  182 , but not fit into the adjacent testing notch  184 . The suture preferably has a diameter of 3.5 mils so that it may disposed within both the swaging notch  182  and the testing notch  184 . Due to the larger relative diameter of the needle vis-a-vis the testing notch  184 , the suture may pass through the testing notch  184 , but the larger diameter needle may not pass through the testing notch  184 , which enables the pull test to be conducted using the hinge mechanism  150  ( FIG. 7 ). 
       FIGS. 9A-9E  show an armed surgical needle including a needle  102  and a suture  104  disposed within the testing notch  184  formed in the top surface  180  of the upper end  166  of the swaging tool  125 . The surgical needle  102  has a larger diameter than the width of the testing notch  184  so that only the relatively smaller diameter suture  104  may pass through the testing notch  184  while the larger diameter needle  102  is caught at an end of the testing notch. The swaging notch  182  is disposed adjacent the testing notch. The proximal end  105  of the needle  102  has a diameter that is larger than the width of the testing notch  184  so that only the suture  104  may pass through the testing notch  184  while the larger diameter needle  102  is caught at the end of the testing notch  184 . 
     Referring to  FIG. 10 , in one embodiment, the hinge mechanism  150  desirably includes a swaging tool support plate  186  that is positioned over the top surface  162  of the top plate  154 . In one embodiment, the swaging tool support plate may include projections that are inserted into the swaging tool support plate openings  168 A- 168 C ( FIG. 6A ). In one embodiment, the swaging tool support plate  186  includes an opening  188  that enables the swaging tool  125  to pass therethrough with the upper end  166  of the swaging tool  125  projecting above the swaging tool support plate  186  to be accessible for swaging and testing operations. The swaging tool support plate  186  preferably supports and maintains the integrity of the swaging tool  125  during swaging and testing operations. 
     Referring to  FIGS. 5C and 11 , in one embodiment, the microprocessor preferably contains one or more swaging and testing programs stored therein. In one embodiment, the swaging system may be utilized to swage and test needles and sutures having different dimensions, sizes, properties and/or configurations. In one embodiment, an operator preferably interacts with an LCD touch screen of the HMI for selecting a particular program for utilization. The program that is utilized may change depending upon the sizes of the needles and sutures being used to form armed surgical needles. The operating programs are preferably stored in one or more microprocessors and/or memory devices. In one embodiment, an operator may modify the load and time parameters of a pull test by inputting data or manipulating controllers and actuators. 
     A plurality of different swaging and pull test programs may be loaded into a swaging system. An operator preferably selects one swaging and pull test program for operating the swaging system. Referring to  FIG. 11 , in one embodiment, a pull test program desirably includes a first stage  200  during which an operator specifies or selects a target inspection load range having a lower and upper load limit, and a time limit having a minimum time for conducting the pull test and a maximum time for conducting the pull test. In one embodiment, a target inspection load range may be between about 95-105 grams. In one embodiment, a minimum time for conducting a pull test may be about 0.1 seconds and a maximum time for conducting a pull test may be about 0.5 seconds. In a more preferred embodiment, the minimum time and maximum time range is between 0.2 seconds-0.5 seconds. In one embodiment, it may be important to establish parameters for the target inspection load and the minimum time and maximum time for testing. If too much load is applied to the suture when testing the attachment of the needle to the suture, the attachment may be weakened or damaged. Similarly, if a load is applied to the suture for longer than the maximum time limit, the suture may begin to creep out of its attachment to the needle. Thus, in one embodiment, it may be important to establish testing ranges for both the amount of load applied to the arm surgical needle and the amount of time that suture is pulled after being attached to the surgical needle. 
     At the next stage designated  202 , an operator may depress a foot pedal for closing the upper and lower dies and swaging a needle to a suture. In one embodiment, during stage  202 , the needle and the suture are positioned within the swaging notch  182  of the swaging tool  125  ( FIGS. 9A-9E ). After the upper and lower dies have closed for swaging the needle to the suture, the upper and lower dies open so that the armed surgical needle may be transferred from the swaging notch to the testing notch  184  ( FIG. 9D ). 
     Referring to  FIG. 11 , in one embodiment, at the stage of the program designated  204 , the armed surgical needle including the needle secured to the end of the suture is transferred from the swaging notch  182  to the inspection notch  184  ( FIG. 9D ). The suture  104  may then be pulled in the direction designated A 2  in  FIG. 7  to commence a pull test. As the suture  104  is pulled to the left in  FIG. 7 , the top plate  154  of the hinge mechanism  150  is moved away from the bottom plate  152  so that the amount of load applied by the top plate to the load cell  174  is reduced. At the stage of the program designated  206 , the load cell reading is transmitted to the microprocessor. In one embodiment, another load reading is taken and transmitted to the microprocessor every 10 milliseconds. Thus, in one embodiment, to reach the minimum time for conducting a single pull test, at least 20 load cell readings are transmitted from the load cell to the microprocessor. If a maximum time of 0.5 seconds is used for obtaining load signals, at least 50 load cell readings are transmitted to the microprocessor. The microprocessor preferably analyzes the load signal data to determine if the load has changed, how much the load has changed, if the measured load change exceeds a predetermined load limit, and the time duration of a pull test. 
     The flow chart disclosed in  FIG. 11  discloses various methodologies and protocols for conducting pull test on armed surgical needles. In a first scenario designated #1, a pull test is commenced. At the stage of the program designated  208 , no change in load is detected so the control system determines that a pull test has not yet commenced. The control system continues to conduct a load reading every 10 milliseconds until it detects a change in load, whereupon the control system determines that the pull test has begun and the control system continues the pull test. 
     In a scenario designated #2, at stage  212 , the microprocessor receives a reading from the load cell that the load change is greater than the upper end of the target inspection load range. In one embodiment, the system controller determines that the load change has been exceeded if the measured load is greater than or equal to 105.1 grams. If the load is exceeded, at stage  214 , the microprocessor sends signals to generate a red light within the stereoscope and an audible buzzer sound that indicates that the armed surgical needle is defective and should be discarded. At stage  216 , after the rejection signals have been transmitted, the control system returns to a zero count. 
     The scenario designated #3 shows an operational protocol wherein the armed surgical needle is maintained within the target inspection load range and within the minimum/maximum time range for conducting a pull test. At the stage of the program designated  218 , the load change is determined to be within the range of 95-15 grams. At stage  220 , if the microprocessor determines that the load change is within an acceptable range, the microprocessor generates a green light within the stereoscope or within the field of view of the stereoscope and begins to calculate the length of the test. The microprocessor is preferably adapted to obtain a load cell reading every 10 milliseconds. 
     At stage  210 , if the minimum time for conducting a test has not been reached, the system continues to collect load readings until the minimum time for conducting a pull test has been reached. In one embodiment, the pull test must be conducted for at least 0.1 seconds and more preferably about 0.2 seconds, and the duration of a pull test should not exceed 0.5 seconds. 
     At stage  222 , the microprocessor analyzes if the minimum time for conducting a test has been attained. If not, then the microprocessor continues to collect load cell readings until the minimum time of 0.2 seconds has been reached. 
     At stage  224 , if the target load has been maintained within the acceptable range for at least the minimum period of time, the microprocessor will flash the green light within the stereoscope and generate a triple audible beep, which indicates that a satisfactory pull test has been achieved. The armed surgical needle product will be acceptable as long as the operator releases the suture and does not continue to pull on the suture for over 0.5 seconds. 
     At stage  226 , the microprocessor evaluates how long the load test has been conducted. In one embodiment, the 0.5 second time limit is the maximum time for conducting the pull test. Once the 0.5 second time limit has been reached, the microprocessor obtains another signal from the load cell at stage  228 . At this time, if there is an increase in the load detected as a result of the operator releasing the tension on the suture allowing the full weight of the upper section of the hinge to press down on the load cell, the inspection is complete and the armed surgical needle product is deemed acceptable (stage  230 ). At stage  232 , if a load change is still detected, the operator is pulling the suture past the prescribed maximum time limit. As a result, the microprocessor generates a red light and an audible rejection buzzer sound at stage  234  to indicate that the length of the pull test has exceeded the maximum allowable time limit and the product should be discarded. 
       FIGS. 12A and 12B  are graphs plotting Needle Pull-Off (NPO) data, which indicates that the lower end of the attachment force population has been eliminated by utilizing the swaging system, apparatus and methods disclosed herein. 
     While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, which is only limited by the scope of the claims that follow. For example, the present invention contemplates that any of the features shown in any of the embodiments described herein, or incorporated by reference herein, may be incorporated with any of the features shown in any of the other embodiments described herein, or incorporated by reference herein, and still fall within the scope of the present invention.