Abstract:
An improved surgical stapler including a digital counter to facilitate easy accounting of the number of staples consumed during a procedure. The surgical stapler also includes audible feedback including a first audible sound to indicate when an individual staple has been formed and a second audible sound to indicate that the stapler is ready to begin another staple forming process. The surgical stapler is of simple construction that lends itself to low cost production and mass assembly techniques thereby enabling it to be a disposable device.

Description:
FIELD OF THE INVENTION 
     This invention relates to skin and fascia staplers, and particularly to a surgical stapler that provides an improved method of counting the total number of staples that is used during a surgical procedure. 
     BACKGROUND OF THE INVENTION 
     Surgical skin or fascia staplers are well known in the medical industry. Their purpose is to join dislocated skin or fascia by inserting surgical staples along the rupture to hold the adjacent portions of skin together until the patient&#39;s natural healing processes enable the separate portions to join together. Over the years, surgeons have converted more and more to the use of surgical staples rather than conventional thread sutures for closing incisions or wounds in the skin or fascia of a patient. 
     Early examples of surgical staplers, such as that of U.S. Pat. No. 3,873,016 to Fishbein, issued Mar. 25, 1975, disclose a pliers-like instrument including a staple driving ram, a staple guide, and an anvil that operate from outside the severed skin. A ratchet means is provided to prevent the pliers handles from reversing or opening once a closing movement has begun. This prevents a second staple from being fed into the staple guide while the one ahead of it is still in the guide. 
     Early versions of surgical staplers were reusable therefore necessitating that the stapler be cleaned and disinfected when used on more than one patient. Later improvements to surgical staplers included the production of disposable models. U.S. Pat. No. 4,109,844 to Becht, issued Aug. 29, 1978 for example, discloses a surgical stapler that may be fabricated in such a way as to constitute a single-use, disposable instrument. 
     In the past, unfortunate incidents have occurred in the operating room where various operating devices or equipment has been left inside of the patient by mistake. In the modern-day operating room it has therefore become imperative that all operating equipment is accounted for prior to closing the operating cavity. This accounting of equipment even extends to small items such as the number of staples that have been used on a patient. U.S. Pat. No. 4,406,392 to Campbell, et al. (hereinafter the &#39;392 patent), issued Sep. 27, 1983 addresses this accounting issue by providing an indicator to indicate the number of staples expended. Although providing a means of accounting for the staples expended, the device of the &#39;392 patent provides only an analog readout. As can be imagined, since the stapler of the &#39;392 patent is a disposable model it is quite compact, and the gradations on the analog scale are located in quite close proximity to one another. A user must then correctly interpolate the reading between two annotated hash marks. Considering that blood or other detritus from the operating site may occlude the viewing window above the indicator, it would be very difficult for a surgeon or assistant to determine the exact number of staples expended in a given procedure. 
     A further disadvantage of the prior art surgical staplers includes the fact that no audible feedback has been provided to indicate when a staple has been inserted. An audible signal would improve the utility of the device by letting surgeons know when a staple has been inserted into the ruptured skin or fascia. 
     SUMMARY OF THE INVENTION 
     The present invention comprises an improved surgical stapler including a digital counter to facilitate easy and accurate accounting of the number of staples consumed during a procedure and audible feedback to indicate when an individual staple has been inserted and when the stapler is ready to form another staple. The surgical stapler is of simple construction that lends itself to low cost production and mass assembly techniques thereby enabling it to be a disposable device. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG.  1  and FIG. 2 are perspective views of the preferred embodiment of the surgical stapler of the present invention. 
     FIG. 3 is a top view of the surgical stapler of FIG.  1 . 
     FIG. 4 is a sectional view taken along lines  4 — 4  of FIG. 3 . 
     FIG. 5 is a detailed view of the digital counter portion of the surgical stapler of FIG.  1 . 
     FIG. 6 is a detailed portion of the sectional view of FIG. 4 showing the details of the forward portion of the surgical stapler of FIG.  1 . 
     FIG. 7 is a perspective view of the surgical stapler of FIG. 1 with the trigger extended and with a portion of the forward housing cut away to show the upper forming strip in its uppermost position. 
     FIG. 8 is a perspective view of the surgical stapler of FIG. 1 with the trigger partially depressed and with a portion of the nose section cutaway to show the upper forming strip in a lower position forming a staple. 
     FIGS. 9,  10 , and  11  are perspective views of the digital counter that shows the nub advancing to various positions as staples are formed. 
     FIG. 12 is a perspective view of a wheel forward arm used in the preferred embodiment of the surgical stapler of FIG.  1 . 
     FIG. 13 is a perspective view of a stop arm used in the preferred embodiment of the surgical stapler of FIG.  1 . 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Index to Reference Numerals in Drawings 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 20 
                 surgical stapler 
               
               
                   
                 22 
                 housing 
               
               
                   
                 24 
                 trigger 
               
               
                   
                 24a 
                 trigger portion 
               
               
                   
                 26 
                 window 
               
               
                   
                 28 
                 mechanical digital counter 
               
               
                   
                 30 
                 handle 
               
               
                   
                 32 
                 V-shaped spring 
               
               
                   
                 34 
                 staple delivery system 
               
               
                   
                 36 
                 staple forming system 
               
               
                   
                 38 
                 forward portion of housing 
               
               
                   
                 40 
                 staple bench 
               
               
                   
                 42 
                 spring 
               
               
                   
                 44 
                 spring guide pin 
               
               
                   
                 46 
                 pin forwarder 
               
               
                   
                 48 
                 upper forming strip 
               
               
                   
                 50 
                 lower forming strip 
               
               
                   
                 52 
                 first digit wheel 
               
               
                   
                 54 
                 second digit wheel 
               
               
                   
                 56 
                 pilot pin 
               
               
                   
                 58 
                 wheel forward arm 
               
               
                   
                 60 
                 stop arm 
               
               
                   
                 62 
                 nub 
               
               
                   
                 64 
                 depression 
               
               
                   
                 64a 
                 deep depression 
               
               
                   
                 66 
                 first end (of wheel forward arm) 
               
               
                   
                 68 
                 second end (of wheel forward arm) 
               
               
                   
                 70 
                 anchored end (of stop arm) 
               
               
                   
                 72 
                 free end (of stop arm) 
               
               
                   
                 74 
                 outer periphery (of first digit wheel) 
               
               
                   
                 76 
                 outer periphery (of second digit wheel) 
               
               
                   
                 78 
                 first pawl (of stop arm) 
               
               
                   
                 80 
                 second pawl (of stop arm) 
               
               
                   
                 82 
                 long pawl (of wheel forward arm) 
               
               
                   
                 84 
                 short pawl (of wheel forward arm) 
               
               
                   
                 86 
                 first side (of second end of wheel forward arm) 
               
               
                   
                 88 
                 second side (of second end of wheel forward arm) 
               
               
                   
                 90 
                 outward facing surface 
               
               
                   
                 92 
                 staple 
               
               
                   
                 94 
                 digit 
               
               
                   
                 96 
                 head cover 
               
               
                   
                 98 
                 skin 
               
               
                   
                   
               
             
          
         
       
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG.  1  and FIG. 2, the preferred embodiment of the surgical stapler  20  of the present invention includes a housing  22 , a trigger  24 , and a window  26  that allows viewing of a mechanical digital counter  28  that increments downward by one digit as each surgical staple is consumed. As shown in the perspective view of FIG.  1  and the top view of FIG. 3, the window  26  is well forward of the handle  30  section of the housing  22  thereby allowing unobstructed viewing of the window  26  and therefore the mechanical digital counter  28  as the stapler  20  is used. 
     Referring to FIG. 4, a sectional view taken along line  4 — 4  in FIG. 3, the surgical stapler  20  includes a first or V-shaped spring  32  that biases the trigger  24  in an extended position away from the housing  22 . A staple delivery system  34  and a staple forming system  36  are located in the forward portion  38  of the housing  22  as shown. The preferred material of construction of the V-shaped spring  32  is spring steel. A head cover  96  is provided to cover and protect the moving parts within the staple forming system  36 . 
     Referring to FIG. 6, a detailed view of the forward portion  38  of the housing  22  depicts the staple delivery system  34  including a staple bench  40 , a spring  42  mounted on a spring guide pin  44 , and a pin forwarder  46 . Staples are delivered from the staple delivery system  34  to the staple forming system  36  which includes an upper forming strip  48  and a lower forming strip  50 . The lower forming strip  50  is typically an integral extension of the staple bench  40 . A mechanical digital counter  28  consists of a first digit wheel  52  (not shown) and a second digit wheel  54  rotatably mounted adjacent to one another on a pilot pin  56  that is secured to the housing  22 . The mechanical digital counter  28  also includes a wheel forward arm  58 , a stop arm  60 , and a nub  62  that is typically integral with and extends from the side of the second digit wheel  54  as shown. Each of the digit wheels  52 ,  54  include depressions in their outer peripheries such as the depressions  64  shown on the second digit wheel  54  which is visible in FIG.  6 . The depressions  64  may, for example, take the form of lateral grooves in the outer peripheries of the digit wheels. The wheel forward arm  58  includes a first  66  and a second end  68  with the first end  66  secured to the trigger  24  and the second end  68  extending into one of the depressions  64  on the outer periphery of the digit wheels. The stop arm  60  includes an anchored end  70  and a free end  72  with the anchored end  70  secured to the housing  22  and the free end  72  extending into one of the depressions  64  in the digit wheels. 
     Details of the mechanical digital counter  28  can be better understood by referring to FIGS. 9 through 11. These figures show perspective views of the digital counter  28  with the first  52  and second  54  digit wheels in various states of rotation. The mechanical digital counter  28  is composed of a first digit wheel  52  and a second digit wheel  54  rotatably mounted on a pilot pin  56 , a wheel forward arm  58 , and a stop arm  60 . Both the first  52  and second  54  digit wheels contain depressions  64  in their outer peripheries  74 ,  76 . The second digit wheel  54  includes a nub extending from the side of the wheel away from the first digit wheel  52 . Although the surgical stapler  20 , including the housing  22  and trigger  24  are not shown in FIGS. 9 through 11, it should be understood that the first end  66  of the wheel forward arm  58  is secured to the trigger (not shown) and the second end  68  extends to the outer peripheries  74 ,  76  of the digit wheels  52 ,  54  and spans at least some portion of each of the wheels. The stop arm  60  includes an anchored end  70  that is secured to the housing (not shown) and a free end  72  having a first  78  and second  80  pawl that extend into one of the depressions  64  on each digit wheel  52 ,  54 . 
     As shown in FIG. 12, a perspective view of the wheel forward arm  58 , the second end  68  of the wheel forward arm  58  includes a long pawl  82  on a first side  86  and a short pawl  84  on a second side  88 . 
     As shown in the perspective view of the stop arm  60  in FIG. 13, the free end  72  of the stop arm  60  includes a first pawl  78  and a second pawl  80 . 
     Referring again to FIG. 9, the long pawl denoted by the reference numeral  82  is barely visible in this figure, but it should be understood that the long pawl  82 , located on the first side  86  of the wheel forward arm  58 , extends into one of the depressions  64  in the first digit wheel  52 . There are typically ten depressions  64  in each digit wheel  52 ,  54  when the preferred embodiment of the surgical stapler is used with the Arabic numeral system. The plurality of depressions  64  in the outer peripheries of the digit wheels  52 ,  54  divide the outer peripheries  74 ,  76  into a plurality of outward facing surfaces  90 . Each of the outward facing surfaces contains a digit  94  as shown. Typically, the first digit wheel  52  includes a digit  94  on each outward facing surface  90  for a total of ten digits. The second digit wheel  54  typically includes the digits zero through four, but is not restricted to these. 
     The principle of operation of the mechanical digital counter  28  of the present invention would best be understood by referring to FIGS. 9 through 11 in sequence. The preferred embodiment of the surgical stapler would typically be produced to hold forty surgical staples. Typically, five of the forty total staples are expended at the end of the production process for quality control purposes leaving thirty-five staples in the stapler when delivered to the user. It should be understood that the surgical stapler of the present invention may be designed to hold more or less than forty staples, but forty total staples are an adequate number to provide for both quality control purposes and for a typical medical procedure in which a surgical stapler would be used. FIG. 9 therefore depicts the mechanical digital counter  28  with the two digits for thirty-four showing through the window  26  (in ghost lines) in the housing (not shown). This is denoting that thirty-four staples remain in the surgical stapler. Upon depressing the trigger (not shown), the wheel forward arm  58  is forced forward by the movement of the trigger, and the long pawl  82 , being disposed within one of the depressions  64  on the first digit wheel  52 , causes the first digit wheel  52  to rotate around the pilot pin  56 . The first digit wheel  52  rotates until the first pawl  78  of the stop arm  60  snaps into the next depression  64  that it encounters. A loud click is created by the stop arm  60  as it snaps into the depression  64 . Since the full depression of the trigger also causes the upper forming strip (not shown) to form a staple, the action of the stop arm  60  snapping into the depression  64  coincides with the forming of a staple. The loud click created by the stop arm  60  therefore notifies the user of the surgical stapler that a staple has been formed. At this point, after the stop arm  60  has snapped into the next depression  64 , the wheel forward arm  58  has reached its maximum extent of travel and the trigger is fully depressed. Release of the trigger at this point causes the wheel forward arm  58  to return to the next depression  64 . As the long pawl  82  of the wheel forward arm  58  aligns with the next depression  64 , the wheel forward arm  58  snaps into the depression  64  and creates a second loud click. The surgical stapler of the present invention therefore notifies the user with a first click when a staple has been formed and by a second click when the stapler is ready to begin another staple forming process. This audible confirmation or feedback enhances the visual confirmation provided by the mechanical digital counter  28 . The audible clicks produced are a function of the material of construction of the stop arm  60  and wheel forward arm  58 , which are typically constructed of a resilient metal strip exhibiting stiffness but also flexibility. The preferred material of construction of the stop arm  60  is stainless steel and the preferred material of construction of the wheel forward arm  58  is phosphor bronze. 
     A mechanism is built into the mechanical digital counter  28  to enable rotation of the second digit wheel  54  at the same time as the first digit wheel  52  has reached zero. As shown in FIG. 13, the depression  64   a  between the outward facing surfaces  90  containing the digits  7  and  8  on the first digit wheel  52  is much deeper than the remaining depressions  64 . Therefore, when the trigger is depressed with a zero displayed on the first digit wheel  52 , upon release of the trigger the second end of the wheel forward arm  58  returns to the next depression between  7  and  8 . Since the depression between  7  and  8  is a deep depression  64   a , the long pawl  82  falls into the deep depression  64   a  causing the short pawl  84  to fall into the standard depression  64  in the second digit wheel  54 . With the long pawl  82  now within the deep depression  64   a  in the first digit wheel  52 , the short pawl  84  has fallen into a standard depression  64  in the second digit wheel  54  thereby enabling the next depression of the trigger to cause the wheel forward arm  58  to advance or rotate both digit wheels  52 ,  54 . The first digit wheel  52  may be thought of as displaying the ones digit and the second digit wheel  54  may be thought of as displaying the tens digit position in the Arabic number system. Therefore, to advance the counter from the digits thirty-four as shown in FIG. 9 to the digits twenty-nine as shown in FIG. 10, five full depressions or cycles of the trigger would be required. For the first four depressions of the trigger, the long pawl  82  would be the only pawl within the depression  64  and would therefore cause the digital counter  28  to count down successively from thirty-four to thirty. When the digits for thirty are displayed at the window  26 , the long pawl  82  has fallen into the deep depression  64   a  between digits  7  and  8  on the first digit wheel  52 . The depression between digits  7  and  8  is the deep depression  64   a  that causes the short pawl  84  to fall into the standard depression  64  in the second digit wheel  54 . The next time the trigger is depressed both the long  82  and short  84  pawls will advance their respective digit wheels  52  and  54  and the number displayed will go from thirty to twenty-nine. After the digits for twenty-nine are displayed in the window  26 , the pawls  82 ,  84  of the wheel forward arm  58  will return to the next depression. Since the only deep depression in the first digit wheel  52  is between the  7  and  8  digits, subsequent depressions of the trigger will advance only the first digit wheel  52  until the digital counter  28  reads twenty. With twenty displayed in the window  26 , the long pawl  82  again falls into the deep depression  64   a  and the next time the trigger is squeezed will advance both digit wheels  52 ,  54  and the digits for nineteen will be displayed. The deep depression  64   a  in the first digit wheel  52  between digits  7  and  8  therefore provides a means to advance both digit wheels  52 ,  54  on the next cycle of the trigger. 
     As shown in FIG.  9  and FIG. 10, a nub  62  is included on the side of the second digit wheel  54  that is away from the first digit wheel  52 . The nub  62  is typically integral with the second digit wheel  54  and therefore rotates with the wheel. As shown in FIG. 9, the nub  62  starts nearly even with the window  26  and every time the second digit wheel  54  is advanced by the short pawl  84 , the nub  62  will be advanced in a counterclockwise manner. This can be seen by the change of the position of the nub  62  as shown in FIG.  9  and then FIG.  10 . Eventually, when the digits 00 show up on the two digit wheels  52 ,  54 , the nub  62  has made contact with a portion  24   a  of the trigger  24 . This stops the rotation of both digit wheels  52 ,  54  and also stops the audible feedback from the surgical stapler as the stop arm  60  and wheel forward arm  58  will be prevented from falling into further depressions  64 . The surgical stapler  20  of the present invention therefore provides both visual and audible confirmation when all staples have been consumed. The visual confirmation is through direct readout of the mechanical digital counter  28  and the audible confirmation is through a cessation of clicks on subsequent depressions of the trigger after the counter reaches 00 digits. The zero digits may also be highlighted in a color different from the color of the remaining digits, to call the user&#39;s attention to the fact that the stapler has expended all the available staples. The audible feedback provides an additional confirmation that is helpful in case blood or other operating debris obscures the window  26 . 
     A perspective view of the surgical stapler  20  in use is shown in FIG. 7. A portion of the housing  22  has been cut away to show the trigger  24  in its extended position. At this time the upper forming strip  48 , which is secured at its top end to the trigger  24 , is in its uppermost position. A staple  92  is visible on top of the lower forming strip  50 . 
     Referring to FIG. 8, a perspective view is shown of the surgical stapler  20  with the trigger  24  partially depressed and with a portion of the housing  22  cut away. With the trigger  24  depressed, the upper forming strip  48  has been forced down by the trigger  24  causing the staple  92  to be bent around the lower forming strip  50  therefore binding the portions of skin  98  together. 
     The surgical stapler  20  of the present invention therefore provides a method of inserting surgical staples into skin or fascia that includes: providing a surgical stapler including a housing, a trigger, a staple delivery system, a staple forming system and staples, providing a mechanical digital counter that increments one digit as each of the staples is consumed, providing an audible feedback system comprised of two clicks denoting the forming of a staple and the return of said trigger to its starting position to begin a new staple forming cycle, and providing a system to lock the mechanical digital counter and stop the audible clicks once all of the staples have been consumed. 
     Although the description above contains many specific descriptions and typical materials of construction, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. 
     Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.