Abstract:
A foot pedal evacuates debris and fluid from the field of view of a camera during arthroscopic procedures. In a first embodiment, the foot pedal houses a ball check valve to control fluid flow, and includes a base and a foot support hingedly mounted to one another. The foot support includes a valve actuator that opens the ball check valve by distorting the shape of its valve seat. The ball check valve includes a pair of connectors at the ends of the valve adapted to accept irrigation tubing. The connectors are in axial alignment with one another in a first embodiment and in parallel relation to one another in a second embodiment. A third embodiment eliminates the ball check valve and a spring-loaded lever pinches a tube to prevent fluid flow. Depression of the foot support overcomes the bias of the spring so that liquid fluid flows through the tube.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to currently pending U.S. Provisional Patent Application 60/826,784, entitled: “Foot Pedal to Aid in Arthroscopic Surgery,” filed Sep. 25, 2006. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to equipment used in surgical procedures. More particularly, it relates to a foot-actuated control valve for use during arthroscopic procedures to effect a controlled purge and replenishment of liquid fluid from the field of view of a camera employed during surgery to view the surgical site. 
         [0004]    2. Description of the Prior Art 
         [0005]    Arthroscopes and other optical instruments such as endoscopes are in common use by orthopedic surgeons because they enable minimally invasive surgery and the many benefits that flow therefrom. For example, the use of such instruments reduces the amount of time required to perform a surgical operation, reduces the patient&#39;s recovery time, reduces the post-operative pain experienced by patients, and is less expensive than traditional surgery. Moreover, the surgery can often be handled on an outpatient basis. 
         [0006]    In arthroscopic surgery, an arthroscope is used to assist in the visual inspection of a joint such as a knee or shoulder joint. The procedure begins with an incision into the joint, and sterile fluid, typically saline, is introduced into the joint space to provide a better view. The arthroscope is then inserted and the inside of the joint is viewed by displaying the image on a monitor. During the procedure tissue and other debris accumulate in the fluid at the site of the procedure and interferes with the field of vision. To clear the view, the fluid at the site is purged and additional sterile fluid is delivered to the site. A fluid circuit is maintained with sterile fluid provided by a remote reservoir in fluid communication with an inlet of the scope. The fluid is thus delivered from the reservoir to the field of view. The circuit further includes an outlet from the field of view for purging the discharge fluid to a remote receptacle or collection tank for discard. The system typically operates under suction with control provided by a stopcock or other hand-controlled valve assembly downstream of the field of view. When the valve is closed, the fluid is statically maintained within the site of the procedure. The surgeon manually opens the stopcock to flush the site and deliver additional fluid. The suction pulls the fluid from the site and delivers fresh fluid from the reservoir of sterile fluid. The surgeon closes the valve to stop the suction when the site is sufficiently flushed. The focus of the arthroscope is then typically readjusted and the procedure is continued. 
         [0007]    Current instrumentation for arthroscopy includes at least three hand-actuated devices that the surgeon cannot manipulate simultaneously. The devices are a camera, at least one surgical tool, and a stopcock. During the procedure the surgeon typically operates the camera with one hand and manipulates the surgical instruments, such as a shaver or biter, with the other hand. To operate the stopcock or other hand-controlled valve assembly, the surgeon must put down either the camera or the surgical instrument to free a hand. If the inlet stopcock is left open, the opening of the outlet stopcock purges the field of view of the fluid to be discarded and delivers sterile fluid to the surgical site. The surgeon must then manually close the outlet stopcock and retrieve the surgical instrument. A typical surgical procedure may require about thirty of such purges, causing the surgeon to have to put down and pick up the surgical instrument that many times. Such action diverts the surgeon&#39;s attention from the field of view each time a purge is required and thus increases the time required to complete the procedure. 
         [0008]    A system is needed that enables a surgeon to purge the field of view without requiring the surgeon to free a hand and divert attention. 
         [0009]    It would be further desirable to have a system that allows the surgeon a degree of control over the applied suction, facilitating controlled delivery of fresh fluid. 
         [0010]    However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill how the identified needs could be fulfilled. 
       SUMMARY OF INVENTION 
       [0011]    The long-standing but heretofore unfulfilled need for improvements in the field of arthroscopy is now met by a new, useful, and nonobvious invention. 
         [0012]    The novel structure includes a foot-actuated control valve assembly, also referred to herein as a foot pedal, adapted to evacuate debris and fluid from the field of view so that a surgeon&#39;s hands are not involved in the purge procedure. In a first embodiment, the structure includes a ball check valve that controls the flow of fluid, an annular check valve seat, and a foot pedal formed by a foot support hingedly secured to a base. The foot support includes a valve actuator that opens the ball check valve by distortion of the check valve seat from its annular configuration responsive to application of pressure to the foot support. 
         [0013]    The ball check valve includes a pair of connectors, also known as tube mounts, at the opposite ends of the valve assembly adapted to accept inlet and outlet irrigation tubes or hoses. In a first embodiment, the tube mounts are straight in configuration and are axially aligned with one another. In a second embodiment, the tube mounts have a ninety degree (90°) bend formed in them so that the inlet and outlet irrigation tubes or hoses are disposed in parallel relation to one another. 
         [0014]    The base includes a pair of clips to secure the valve within the base of the foot pedal. The top surface of the foot support is textured to facilitate the placement of the foot of a user and inhibit slippage. The base and the foot support are fabricated of disposable plastic to make the unit suitable for one-time use followed by disposal. In a second embodiment, the ball check valve is replaced by a simple tube and a spring-loaded lever that pinches the tube in a normally closed configuration when the spring is in repose. Stepping on the foot pedal pivots the lever so that the bias of the spring is overcome and liquid fluid can flow through the tube. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    For a fuller understanding of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which: 
           [0016]      FIG. 1  is a diagrammatic view of an illustrative embodiment of the invention; 
           [0017]      FIG. 2  is a diagrammatic view similar to that of  FIG. 1  but with the reservoir and collection tank omitted; 
           [0018]      FIG. 3A  is a perspective view of a first embodiment of the novel foot pedal; 
           [0019]      FIG. 3B  is a perspective view of a second embodiment of the novel foot pedal; 
           [0020]      FIG. 3C  is a perspective view of a third embodiment of the novel foot pedal; 
           [0021]      FIG. 3D  is a perspective view of a fourth embodiment of the novel foot pedal; 
           [0022]      FIG. 3E  is a perspective view of a fifth embodiment of the novel foot pedal; 
           [0023]      FIG. 4A  is a perspective view of a first embodiment of the novel foot pedal base; 
           [0024]      FIG. 4B  is a perspective view of a second embodiment of the novel foot pedal base; 
           [0025]      FIG. 4C  is a perspective view of a third embodiment of the novel foot pedal base; 
           [0026]      FIG. 5A  is a perspective view of a first embodiment of the underside of the novel foot support; 
           [0027]      FIG. 5B  is a perspective view of a second embodiment of the underside of the novel foot support; 
           [0028]      FIG. 5C  is a perspective view of a third embodiment of the underside of the novel foot support; 
           [0029]      FIG. 6A  is a longitudinal sectional view depicting the valve assembly that is opened and closed by the novel foot pedal; 
           [0030]      FIG. 6B  is a perspective view of the valve assembly of  FIG. 6A ; 
           [0031]      FIG. 6C  is an elevational view depicting the valve assembly of  FIGS. 6A and 6B  when installed in the base of the novel foot pedal; 
           [0032]      FIG. 7A  is a diagrammatic top plan view of a second embodiment of the valve assembly; 
           [0033]      FIG. 7B  is a diagrammatic side elevational view of the second embodiment of the valve assembly; 
           [0034]      FIG. 7C  is a diagrammatic front elevational view of the second embodiment of the valve assembly; 
           [0035]      FIG. 8A  is a perspective view of the third embodiment of the invention; 
           [0036]      FIG. 8B  is a side elevational view of said third embodiment; 
           [0037]      FIG. 9A  is a perspective view of the third embodiment with the foot support removed; 
           [0038]      FIG. 9B  is a perspective view like  FIG. 9A  but with the lever and related parts removed; and 
           [0039]      FIG. 9C  is a top plan view of the parts depicted in  FIG. 9B . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0040]    Referring now to  FIG. 1 , there it will be seen that the novel system is denoted as a whole by the reference numeral  10 . 
         [0041]    The interior of waste-collection tank  12  is under suction, i.e., a suitable vacuum pump, not shown, is employed to maintain said interior below atmospheric pressure. Hose or tubing  14  provides fluid communication between tank  12  and an outlet port of novel foot pedal  16 . Hose or tubing  18  provides fluid communication between an inlet port of foot pedal  16  and outlet stopcock  32  of camera  20 , and hose or tubing  22  provides fluid communication between inlet stopcock of  30  camera  20  and a source of sterile solution  24 ,  24 . 
         [0042]    Instead of maintaining tank  12  under negative pressure, positive pressure pump  26  may be positioned between sterile solution  24  and inlet stopcock  30 . 
         [0043]    Foot pedal  16  is the actuator for a normally closed valve, not depicted in  FIG. 1 , that prevents flow of sterile solution from source  24  when said valve is in its closed position of repose. When actuated by a surgeon&#39;s foot, said normally closed valve opens and the pressure in hose  22 , and the suction in hose  14 , causes flow of sterile solution  24  through camera  20  and into waste collection tank  12 . 
         [0044]      FIG. 2  is similar to  FIG. 1  but omits collection tank  12  and reservoir  24 . Camera  20  is connected to sheath  28 . Hose  22  is connected to inlet stopcock  30  and hose  18  is connected to outlet stopcock  32 . In the prior art, inlet stopcock  30  is left open and the surgeon manually opens and closes outlet stopcock  32  as needed during the course of a procedure. Such opening and closing requires the surgeon to put down a surgical tool to free up a hand to manipulate the stopcock. In the novel system, both the inlet stopcock  30  and the outlet stopcock  32  are in their respective fully open configurations for the duration of the procedure. However, the check valve in foot pedal  16  is normally closed so no solution flows even when said stopcocks are open. When fluid flow is desired, the surgeon steps on foot pedal  16 , thereby opening the normally closed valve therewithin and enabling flow of sterile solution  24  until the foot is lifted from pedal  16  at which time a spring or other suitable bias means returns the pedal to its normally closed position of repose and fluid flow is terminated. Thus there is no need for the surgeon to put a surgical tool down and to pick it back up again to manipulate a stopcock. 
         [0045]    No further disclosure is required to enable those of ordinary skill in the mechanical arts to make and use the invention. Foot pedal  16  can be made in many different ways, and all such ways are within the scope of this invention. 
         [0046]    One way of making foot pedal  16  depicted in  FIG. 3A . Flat foot-support  34  is pivotally connected to stationary base  36 . Surface  35  of foot support  34  is textured to supply a high coefficient of friction to enable rocking motion of foot support  34  about base  36  in the substantial absence of foot slippage. 
         [0047]    The width of foot support  34  is increased in  FIG. 3B  relative to the width thereof in  FIG. 3A . 
         [0048]      FIG. 3C  depicts another alternative embodiment of foot pedal  16 . The surface area of the foot support surface  34  is increased to facilitate placement of a user&#39;s foot. 
         [0049]      FIG. 3D  also depicts an alternative embodiment of foot pedal  16 . More particularly,  FIG. 3D  depicts foot pedal  16  of reduced size, enabling the placement of foot pedal  16  in tighter spaces. 
         [0050]      FIG. 3E  depicts yet another alternative embodiment of foot pedal  16 . As will be better understood in connection with  FIGS. 4A-C , and  FIGS. 5A-C  that follow, the hinged connection between foot support  34  and base  36  is positioned at the proximal end of pedal  16  as distinguished from the distal end as in the other embodiments. Moreover, notch  37  formed in opposing sidewalls of foot support  36  accommodates a valve assembly disclosed hereinafter. 
         [0051]      FIG. 4A  depicts base  36  in increased detail. Openings  50 ,  50  accommodate the respective ends of rubber hose attachments  46 ,  48 , disclosed hereinafter in connection with  FIGS. 6A-C , that abut opposite ends of rubber tubing  44 , also disclosed in connection with said  FIGS. 6A-C . Transversely spaced apart clips  52 , of which there are two, are formed integrally with base  36  and snugly receive said rubber tubing  44 . Springs  54 ,  54  return foot support  34  to its position of repose when the surgeon&#39;s foot is separated from said foot support, thereby causing a check ball, disclosed hereinafter, to return to its annular valve seat so that solution flow terminates in the absence of manual manipulation of the stopcock. Hinge pin  56  is formed integrally with base  38  at its highest end. 
         [0052]    In an alternative embodiment of base  36  depicted in  FIG. 4B , cover  39  covers the open lower end of said base, leaving clips  52  and hinge pin  56  uncovered. Springs  54  are positioned on the interior of the opposing vertical sidewalls of the base. Said springs return foot support  34  to its undepressed position of repose when released by the user as aforesaid. The opposing sides of the base are embossed “IN” and “OUT” as appropriate adjacent openings  50 . 
         [0053]      FIG. 4C  depicts another alternative embodiment of base  36 . It has a relatively narrow structure and is used with a narrow foot support, such as depicted in  FIG. 5C . Base  36  includes a pair of knobs  47  that extend into the hollow interior of base  36  from its opposing vertical sidewalls. Rubber bands to aid in the opening of foot support  34  are secured to said knobs  47 . Base  36  further includes retaining clips  49  (not shown in drawing), for the valve assembly, positioned adjacent openings  50  that accommodate the inlet and outlet tubes of the valve assembly. Base  36  further includes stop  54  for limiter  62  that forms a part of the foot support embodiment of  FIG. 5C . 
         [0054]      FIG. 5A  depicts the underside of a first embodiment of foot support  34 . Socket  58  formed integrally with said underside of said foot support snugly and rotationally receives hinge pin  56  of base  36  to thereby provide the pivotal or rocking motion between foot support  34  and base  36 . 
         [0055]    Valve actuator  60  is formed integrally with foot support  34  and depends from an underside thereof. A pair of limiters  62  are also integrally formed with said foot support on said underside; said limiters limit the separation between foot support  34  and base  36  when said foot support is in its position of repose. A user will typically rest his or her foot on or near foot pedal  16  during the surgical procedure. The user will begin depression of the pedal with a foot by applying pressure to textured surface  35  of foot support  34  when the user&#39;s field of vision is obscured. Upon said depression of foot pedal  16 , valve actuator  60  abuts against an annular valve seat disclosed hereinafter to unseat a check ball from said valve seat so that sterile fluid from reservoir  24  may purge the surgical site. 
         [0056]    A problem arises if valve actuator  60  over-compresses the valve assembly. More particularly, excess compression can shut the valve off completely. Various solutions to this problem include limiting the depth, or altering the shape of valve actuator  60 , or both as depicted in  FIG. 5B  to ensure the actuator does not over compress the valve. Upon relief of pressure on foot support  34 , it separates from base  36  and actuator  60  withdraws from its abutting contact with the valve assembly. A spring, disclosed hereinafter, returns foot pedal  16  to its position of repose, resulting in the suction on the fluid terminating with respect to the fluid at the field of view. In this manner the fluid in the field of view is purged. 
         [0057]      FIG. 5B  depicts an alternative embodiment of foot support  36  as mentioned above. Valve actuator  60   a  is modified by rounding off sharp edges from its periphery where it contacts the top of the valve assembly and its depth is reduced to prevent over-compression of the valve. 
         [0058]      FIG. 5C  illustrates another alternative embodiment of foot support  34 . It also includes a pair of limiters  62  that limits the upward separation of foot support  34  from base  36 . Each limiter  62  abuts stop  55  of base  36  as depicted in  FIG. 4C . Supports  61  strengthen valve actuator  60 . 
         [0059]      FIG. 6A  depicts valve assembly  39  that includes check ball  38  held against annular valve seat  40  by spring  42 . Radially inwardly-extending valve seat  40  is formed integrally with rubber tubing  44 . Check ball  38  and spring  42  are positioned within the lumen of said rubber tubing  44 . The length of rubber tubing  44  is substantially equal to the width of base  36 . First rubber hose attachment  46  abuts a first end of rubber tubing  44  and second rubber hose attachment  48  abuts an opposite, second end of rubber tubing  44 . Moreover, first rubber hose attachment  46  ensleeves inlet hose  18  and second rubber hose attachment  48  ensleeves outlet hose  14 . When the foot pedal is depressed, valve actuator  60  or  60   a  bears against annular valve seat  40  and distorts it into an oblong or other non-annular configuration so that liquid fluid leaks around spherical ball valve  38 . 
         [0060]      FIG. 6B  depicts valve assembly  39  when not installed on foot pedal  16  and  FIG. 6C  depicts the valve assembly when installed on base  36  of foot pedal  16 . 
         [0061]      FIGS. 7A-C  depict a second embodiment of the novel valve system structure in top, side, and front views, respectively. This novel structure includes outlet and inlet connectors  14 ,  18 , respectively, arranged in parallel relation to one another on the same side of pedal  16  as illustrated in  FIG. 7A . Specifically, outlet and inlet tubes  14 ,  18  are positioned at the distal end of foot pedal  16 , i.e., in a location remote to the toes of a user. This arrangement reduces the clutter of the lines around the user&#39;s feet and therefore provides a greater degree of safety. 
         [0062]    As perhaps best understood in connection with  FIG. 7C , spring  70  urges washer  72  upwardly. Nut  74  limits the maximum expansion of said spring  70 . Spring  70  ensleeves post  76  which is supported by boss  78 . Post  76  is displaced downwardly when foot support  34  is depressed, thereby loading spring  70 . Check valve  80 , sealed by rubber O-ring  82 , is unseated from annular valve seat  84  when said post is depressed, thereby allowing sterile fluid to flow from reservoir  24  to collection tank  12  as indicated by the plurality of flow arrows. 
         [0063]      FIGS. 8A-B  and  9 A-D depict a third embodiment, denoted  90  as a whole. Foot pedal  90  includes base  92  and foot support  94  that are hingedly connected to one another along a top or distal edge thereof. 
         [0064]    As best understood in connection with  FIGS. 9A-D , this embodiment eliminates the ball check valve of the first and second embodiments. Truncate tube  96  is formed of a compressible, flexible and resilient material such as rubber, elastomeric plastic or the like and is attached at its opposite ends to tube mounts  98   a ,  98   b  ( FIGS. 9B-C ) and as depicted in  FIG. 9A , tube  96  is pinched and normally closed by spring-loaded lever  100 . Transversely disposed pin  102  extends through lever  100  and the opposite ends of said pin are rotatably retained by transversely spaced apart retainers  104   a ,  104   b . Spring  106  or other suitable bias means provides constant upward pressure on the trailing end  100   a  of lever  100  so that leading end  100   b  of lever  100  bears downwardly against tube  96 , thereby pinching it so that no liquid fluid can flow through said tube. A suitable, preferably bulbous, protrusion having a linear extent greater than the diameter of tube  96  is formed on the underside of leading end  100   b  to facilitate the pinching action. 
         [0065]    As best understood in connection with  FIG. 8B , valve actuator  60  depends from an underside of foot pedal  94  and abuttingly engages trailing end  100   a  or lever  100  so that full depression of said foot support  94  lifts leading end  100   b  of lever  100  from truncate tube  96  so that liquid fluid may flow therethrough. A physician controls the rate of fluid flow by manipulating the amount of compression of spring  106 . A shallow recess  106   a  ( FIGS. 9B-C ) is formed in a bottom wall of base  92  to accept a lower end of said spring. 
         [0066]    Tube mounts  98   a ,  98   b  are housed in housings  99   a ,  99   b  and have a ninety degree (90°) bend formed in them as best understood in connection with  FIG. 9B . The respective ends  98   c ,  98   d  of said mounting tubes that do not engage truncate tube  96  are flush with the distal end of base  92  and are concentrically positioned within countersunk openings  108   a ,  108   b . Inlet hose  18  is thus easily connected to tube mount  98   c  and outlet hose  14  is easily connected to tube mount  98   d . This is the same connection made in the embodiment of  FIGS. 7A-C . 
         [0067]    Pedals  16  or  90  can be made of reasonably inexpensive components, thus making it suitable for disposal following a single surgical procedure. Valve assembly  39  can be single use as well. Pedal  16  may also be sterilized and a new valve added after each procedure. 
         [0068]    It will be seen that the advantages set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
         [0069]    It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.