Abstract:
A clamp for a surgical retractor system. The clamp has a tapered conically shaped washer against and through which clamping force is applied to place the clamp in a clamped position. The clamping force is applied by a cam head connected to a central shaft. A locking pin connects the cam head to the shaft. Apertures are provided in the clamp for receiving rod ends of a surgical retractor. Such apertures are circular and are positioned to be closer to the top and bottom edges of the clamp portion of the clamp than to the end edge of the clamp portion.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to retractor systems for use during invasive surgical medical procedures. 
         [0002]    During surgical medical procedures, a surgeon will typically make an incision in a patient to access the site of interest for the particular surgical procedure. To maintain clear access to the site of interest, a surgical retractor system is typically utilized. A surgical retractor system typically consists of a rail clamp, a frame connected to the rail clamp by a universal connecting joint mechanism, and retractor blades that are connected to the frame by additional universal connecting joint mechanisms. The rail clamp is commonly secured to an operating table and provides a fixed and sturdy support for the frame and the retractor blades. Each of the components in a typical surgical retractor system is conventionally made of stainless steel. The reason that stainless steel is generally used is that stainless steel is easily sterilized. As would be expected, before any use of the surgical retractor system can be made during a surgical procedure, the system must be thoroughly sterilized for the protection of the patient. 
         [0003]    Surgical retractor systems have been made of other materials in the past, such as aluminum and titanium. The common characteristic of all of these materials is that they are highly durable and easily sterilized. That is, these materials are not porous and easily lend themselves to typical sterilization procedures used in modern day hospitals. 
         [0004]    Accordingly, it is an object of the invention to provide a surgical retractor system that can be used confidently in surgical procedures. 
         [0005]    It is a further object of the invention to provide a universal clamping mechanism for a surgical retractor system. 
         [0006]    It is a further object of the invention to provide a clamping mechanism that is strong against wear caused by continual use of the clamping mechanism over time. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    These and other objects of the invention are achieved in a surgical retractor system which includes at least one clamp. The surgical retractor system may include a cam head having a flat latching surface, a tapered area washer configured to receive a central shaft and apply force to the at least one clamp, a locking pin configured to connect the central shaft to the cam head, and/or an offset applied to a passage used to clamp rods in the surgical retractor system. 
     
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a typical surgical retractor system. 
           [0009]      FIG. 2  is an elevated view of a rail clamp with a universal clamping mechanism of the present invention and a cross bar for insertion into the insulated universal clamping mechanism. 
           [0010]      FIG. 3  is a perspective view of the universal clamping mechanism of the present invention with an insulating sleeve. 
           [0011]      FIG. 4  is a side view of the universal clamping mechanism of  FIG. 3  and in its open position. 
           [0012]      FIG. 5  is a side view of the universal clamping mechanism of  FIG. 3  and in its closed position. 
           [0013]      FIG. 6  is a side view of the cam head of the clamping mechanism of  FIG. 3 . 
           [0014]      FIGS. 7A, 7B and 7C  are views of a washer and a clamp of the clamping mechanism of  FIG. 3 . 
           [0015]      FIG. 8  is a side view of the washer of  FIG. 7 . 
           [0016]      FIG. 9  is a side view of a washer of the clamping mechanism of  FIG. 3 . 
           [0017]      FIG. 10  is a top view of the clamping mechanism of  FIG. 3 . 
           [0018]      FIG. 11  is a cross sectional side view of the clamping mechanism of  FIG. 9  along lines A-A. 
           [0019]      FIG. 12  is a side view of a shaft of clamping mechanism of  FIG. 3 . 
           [0020]      FIG. 13  is an exploded view of some components of the clamping mechanism of  FIG. 3   
           [0021]      FIG. 14  is an exploded view of some components of the clamping mechanism of  FIG. 3   
           [0022]      FIG. 15  is a side view of a second embodiment of a universal clamping mechanism. 
           [0023]      FIG. 16  is a side view of a third embodiment of a universal clamping mechanism. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    In the following detailed description, spatially orienting terms are used such as “left,” “right,” “vertical,” “horizontal,” and the like. It is to be understood that these terms are used for convenience of description of the preferred embodiments by reference to the drawings. These terms do not necessarily describe the absolute location in space, such as left, right, upward, downward, etc., that any part must assume. 
         [0025]    As shown in  FIG. 1 , a surgical retraction system  10  includes an adjustable rail clamp  12  which is securable to a conventional surgical table  16 . A second adjustable rail clamp (not shown) may be secured to the opposite side of the surgical table for increased stability if desired or needed. A post  17  extends vertically from clamp  12  to provide support for a cross bar  18  which in turn provides support for a pair of extension arms  19 ,  20 . Cross bar  18  is secured to post  17  by a multi-directional joint clamp  21 . Extension arms  19 ,  20  are respectively secured to cross bar  18  by a pair of multi-directional joint clamps  22 ,  24 . Additional joint clamps  26 ,  28  are disposed along extension arms  19 ,  20  for rigidly securing any number of retractor blades  34 ,  36  to extension arms  19 ,  20 . As will suggest itself, extension arm  19  may be secured directly to post  17  by a joint clamp, thus in many circumstances eliminating the need for cross bar  18 . 
         [0026]    The purpose of this frame is to securely connect the retractor blades  34 ,  36  to the rail clamp  12  to eliminate unwanted relative movement between the retractor blades  34 ,  36  and the surgical table  16 , this may be accomplished by connecting the retractor blades to the cross bar  18  directly or through extension arms  19 ,  20 , or, as already noted, by connecting extension arms  19 ,  20  directly to the rail clamp. 
         [0027]    Each retractor blade  34 ,  36  includes a blade portion  42  and a retractor arm  44 . Blade portion  42  extends downwardly into the incision  46  made by the surgeon. Blade portion  42  is used to retract anatomy to make the incision  46  accessible to the surgeon. 
         [0028]      FIG. 2  is an elevated view of the rail clamp  12  and cross bar  18 . Of course, as noted above, extension arm  19  or  20  may be connected directly to adjustable rail clamp  12 . The rail clamp includes a clamp  50  that may be secured to surgical table  16  ( FIG. 1 ). This may be a conventional clamp as presently used in the industry and provides for a secure attachment of the adjustable rail clamp  12  to the surgical table  16 . Multi-directional joint clamp  21  is shown at the upper most extremity of post  17 . This position of the multi-directional joint clamp  21  enables the user to locate cross bar  18  at a height sufficient for the surgical retractor system  10  ( FIG. 1 ) to be used during surgical procedures.  FIG. 2  further shows joint clamps  22 ,  24  in their position on cross bar  18 . Clamps  22  and  24  may be identical to each other or different depending on the intended use of each of those clamps. Additionally, these joint clamps  22 ,  24  may each be the same as or different to the multi-directional joint clamp  21  on post  17 . 
         [0029]    Referring to  FIGS. 3-5 and 14 , multi-directional joint clamp  21  includes a first clamp  52  and a second clamp  54 . Joint clamp  21  includes a central shaft  56  as well as a cam lever  58  for bringing first clamp  52  and second clamp  54  into a clamping position or into an unclamping position. Joint clamp  21  may also include a washer  57  positioned between the cam lever  58  and the first clamp  52 . 
         [0030]    The first clamp  52  may include a passage  70 , which is intended to accommodate, for example, post  17  of rail clamp  12  ( FIG. 2 ). Similarly, the second clamp  54  may include a passage  72 . Passage  72  is intended to accommodate, for example, cross bar  18  ( FIG. 2 ). This type of joint clamp is more fully described in U.S. Pat. No. 5,897,087 and 6,033,363, which are incorporated herein by reference. 
         [0031]    The first cylindrical passage  70  of the first clamp  52  is defined by a broken cylindrical surface  71 . The cylindrical surface  71  is broken along two parallel legs  73 ,  74  which run the axial length of the surface  71  to define a gap  75 . Legs  73 ,  74  are movable with respect to one another in order to shorten the gap  75  and thus constrict the area circumscribed by cylindrical surface  71 . Each leg  73 ,  74  defines a respective planar surface  76 ,  77 . Each planar surface  76 ,  77  is generally parallel to the longitudinal axis of cylindrical passage  70 . The application of a clamping forces directs forces against an upper surface  78   a  and a lower surface  78   b  of the first clamp  52  in a direction toward the gap  75  and parallel to the longitudinal axis of shaft  56  and serves to move planar surfaces  76 ,  77  toward each other constricting the area within cylindrical passage  70 . 
         [0032]    Similarly, the second cylindrical passage  72  of the second clamp  54  is defined by a broken cylindrical surface  80 . The cylindrical surface  80  is broken along two parallel legs  82 ,  84  which run the axial length of the surface  80  to define a gap  86 . Legs  82 ,  84  are movable with respect to one another in order to shorten the gap  86  and thus constrict the area circumscribed by cylindrical surface  80 . Each legs  82 ,  84  defines a respective planar surface  90 ,  92 . Each planar surface  90 ,  92  is generally parallel to the longitudinal axis of cylindrical passage  80 . The application of a clamping force directs forces against an upper surface  94   a  and a lower surface  94   b  of the second clamp  54  in a direction toward the gap  86  and parallel to the longitudinal axis of shaft  56  and serves to move planar surfaces  90 ,  92  toward each other constricting the area within cylindrical passage  72 . 
         [0033]    The clamp  52 ,  54  further include locking teeth. In particular, a first set of locking teeth  99   b  is disposed on the lower surface  78   b  of first clamp  52  and a second set of locking teeth  99   a  is disposed on the upper surface  94   a  of second clamp member  54 . The sets of locking teeth  99   a,    99   b  engage each other when clamp members  52 ,  54  are compressed together by cam lever  58 , thereby fixing the positions of clamps  52 ,  54  relative to one another. 
         [0034]    The cam lever  58  includes a cylindrical shaped handle  81  having a distal end  83  connected to a cam head  85 . Cam head  85  is pivotally mounted to central shaft  56  such that rotation of the cam lever  58  about a pivot axis  88  brings first clamp  52  and second clamp  54  into clamping positions and unclamping positions. The shaft  56  may be cylindrical in cross section and may extend through the cylindrical apertures  112 ,  116  in clamp members  52 ,  54 . 
         [0035]    Referring now to  FIG. 6 , an outer edge  100  of the cam head  85  is eccentric, i.e. multiply curved, such that the distance D between the pivot axis  88  and the upper surface  91  of the washer  57  increases as the cam lever  58  is moved from its open position (e.g.,  FIG. 4 ) towards its closed position (e.g.,  FIG. 5 ). Hence, movement of cam lever  58  towards its closed position draws shaft  56  upwardly through cylindrical apertures  112 ,  116 , compressing clamp members  52 ,  54  between the outer edge  100  of the cam head  85  and a stop, such as the nut  113 , secured to the distal end of shaft  56 . Compression of the resilient clamp members  52 ,  54  initially causes the sets locking teeth  99   a,    99   b  to engage each other, thereby fixing the positions of the clamp members  52 ,  54  relative to each other. Further compression of clamp members  52 ,  54  constricts the area circumscribed by cylindrical passages  70 ,  72  to secure clamps  52 ,  54  to the arms passing through cylindrical passages  70 ,  72 . 
         [0036]    Rotation of cam lever  58  towards its open position moves shaft  56  downwardly through cylindrical apertures  112 ,  116 . Due to the downward movement of shaft  56 , the nut  113  may be urged away from aperture  116 , thus reducing or removing a clamping force applied to resilient clamps  52 ,  53 . At the open position, clamps  52 ,  54  are loosely held on shaft  56 , and may be rotated relative to one another about shaft  56 . The nut  113  may prevent clamps  52 ,  54  from being removed for the shaft  56 . The removed or reduced compression on clamps  52 ,  54  may cause cylindrical passages  70 ,  72  to expand their diameter, allowing clamps  52 ,  54  to be moved relative to posts positioned in cylindrical passages  70 ,  72 . The open position may also allow the various clamp components to be accessed for cleaning. 
         [0037]      FIG. 4  shows the two clamps  52 ,  54  in their unclamped positions. Cam lever  58  is rotated upwardly to an open position for releasing or untightening of clamps  52 ,  54 . In this open position, a release surface  87  of cam head  85  is moved or rotated to a position above washer  57  providing little or no contact between cam head  85  and washer  57  and reducing the distance D between the pivot axis  88  and the upper surface  91  of the washer  57 . This removes the force on clamps  52 ,  54  allowing them to expand and open their respective passages  70 ,  72  to a full extent. 
         [0038]      FIG. 5  shows the two clamps  52 ,  54  in their clamped positions. Cam lever  58  is rotated downwardly to a closed position for tightening of clamp  52 ,  54 . In this closed position, release surface  87  is rotated away from washer  57  and a flat planar surface  89  of cam head  85  engages washer  57 . To enter this closed position, a clamping force is applied to clamps  52 ,  54  which constricts passages  70 ,  72 . 
         [0039]    Planar surface  89  serves to lock handle  81  into position. Because surface  89  is a flat planar surface and contacts the flat planar top surface  91  of the washer  57 , the reverse movement of cam lever  58  into an open position requires more force making it difficult for cam head  85  to unintentionally loosen and rotate away from its closed position of  FIG. 5 . 
         [0040]      FIG. 6  is a side view of cam head  85  illustrating the surfaces  87 ,  89 . Surfaces  87 ,  89  extend across the bottom of cam head  85 . Surfaces  87 ,  89  are positioned on the cam head relative to axis  88  so as to engage the flat top surface  91  ( FIG. 5 ) of washer  57  when the cam lever  58  is pivoted. 
         [0041]    Referring to  FIGS. 7A-7C  and  FIG. 8 , washer  57  is generally cylindrical in shape, and has a cone-like configured shape at its bottom. Washer  57  includes an outer cylindrical surface  101  and a truncated cone surface  103 . An aperture  105  extends fully through the washer terminating at the end of cone surface  103 . Aperture  105  has a diameter to receive central shaft  56  ( FIG. 4 ) which is cylindrical in shape. 
         [0042]    Referring to  FIGS. 4, 10 and 11 , central shaft  56  extends into cam head  85  and is rotatably secured in place by a cam pivot pin  135 . This allows pivoting of cam lever  58  into its open position ( FIG. 4 ) and into its closed position ( FIG. 5 ). 
         [0043]    Referring again to  FIGS. 7A-7C , clamp  52  has a conically shaped aperture  111  to receive and mate with the conical surface  103  of washer  57 . As shown in  FIG. 7C , conical aperture  111  meets with cylindrical aperture  112  which has a diameter to receive central shaft  56 . Similarly, clamp  54  has a conically shaped aperture  114  to receive and mate with the conical surface  119  of nut  113 . See,  FIG. 14 . As shown in  FIG. 14 , conical aperture  114  meets with cylindrical aperture  116  which has a diameter to receive central shaft  56 . 
         [0044]    As shown in  FIG. 4 , a nut  113  is threadedly secured onto the distal end of shaft  56 . Threads  115  are shown in  FIG. 12 . Referring to  FIG. 9 , nut  113  is generally cylindrical in shape, having a cone-like configured shape at its top. Nut  113  includes a cylindrical surface  117  and a truncated cone surface  119 . An aperture  121  extends fully through nut  113  terminating at the end of conical surface  119 . Aperture  121  has a diameter to receive central shaft  56  and has threads  122  to mate with threads  115  on shaft  56  ( FIG. 12 ). 
         [0045]    The nut  113  may be welded to the shaft  56  after being threadedly secured to the distal end of the shaft  56 . Such welding may prevent further rotation of the nut  113  in relation to the shaft  56  about a longitudinal axis of the shaft  56 , but may permit rotation of the nut  113  with respect the clamps  52 ,  54  about the longitudinal axis of the shaft  56 . Because nut  113  is rounded, the shaft  56  with welded nut  113  may be rotated 360°, even when nut  113  is partially drawn into aperture  116 . This may permit the surgeon to rotate handle  81  to a convenient position, even after clamps  52 ,  54  have been compressed. 
         [0046]    Prior to welding, the nut  113  may be rotated in one direction (e.g., clockwise) to tighten the nut  113  and increase a clamping force applied by the clamps  52 ,  54  and may be rotated in the opposite direction (e.g. counter-clockwise) to loosen the nut  113  and decrease the clamping force applied by the clamps  52 ,  54 . In this manner, the clamping force of the clamps  52 ,  54  may be calibrated to a desired force. After obtaining the desired, calibrated clamping force, the nut  113  may be welded to ensure the nut  113  does not rotate further and the desired, clamping force is maintained. 
         [0047]    Referring again to  FIG. 3 , cam head  85  is shaped to include two extending side members  123 ,  125  forming an interposed channel  127 . Channel  127  is defined by two planar side surfaces  129 ,  131  ( FIG. 13 ) of the side members  123 ,  125 . Each side member includes a cylindrical aperture  133  ( FIG. 3 ) which are aligned along their axis. A cam pin  135  ( FIG. 3 ) passes through cylindrical apertures  133 . Cam pin  135  is held fixed relative to cam head  85 . 
         [0048]    As shown in  FIG. 12 , a top end  137  of the shaft  56  is generally planar in shape as best seen in  FIG. 13 , for movement within channel  127 . Top end  137  ( FIG. 12 ) includes a cylindrical aperture  139  for receiving cam pin  135  ( FIG. 11 ) of cam head  85 . Top end  137  rotates about cam pin  135 .  FIGS. 10 and 11  illustrate the shaft  56  being rotatably connected to cam pin  135 . 
         [0049]    As shown in  FIG. 12 , shaft  56  includes an additional cylindrical aperture  141  which passes through top end  137 . Aperture  141  is located orthogonal to aperture  139 , and aperture  141  is positioned to intersect with aperture  139 , as shown in  FIG. 12 . Aperture  141  is sized to receive a lock pin  143 , as shown in  FIG. 11 . 
         [0050]    Referring to  FIG. 13 , the lever  58  is assembled, by initially positioning the top end  137  of shaft  56  into channel  127  of cam head  85 . Cam pin  135  is next passed through apertures  133  ( FIG. 3 ) in each of side members  123 ,  125  of the cam head and into aperture  139  ( FIG. 12 ) of the shaft head. Finally, lock pin  143  ( FIG. 13 ) is passed through aperture  141  ( FIG. 12 ) located in the top end of shaft  56  and is passed through an aperture  145  in cam pin  135 . 
         [0051]    Thus, shaft  56  is held in position by both the aperture  139  in the shaft as well as the lock pin  143 . Lock pin  143  secures the shaft  56  to the cam pin  135 , and thus increases the wear surface between shaft  56  and the cam head  85 . 
         [0052]    Referring to  FIG. 14 , hole passages  70 ,  72  of the two clamps  52 ,  54  are shaped in an offset manner. Particularly, the wall thickness at  151  above each of hole passages  70 ,  72  and the wall thickness at  153  below each of hole passages  70 ,  72  is set at 0.070 inches. Whereas, the wall thickness at  155  between the hole and the distal end of the respective clamps is 0.100 inches. This, slight offset of the hole position serves to prevent the collapse of the hole due to continued use of the clamp without rods located in the hole passages  70 ,  72 , e.g., without a retractor arm  44  ( FIG. 1 ) or extension arms  19 ,  20  or cross bar  18  or post  17 , within hole passages  70 ,  72 . 
         [0053]    As shown in  FIG. 15 , a second multi-directional joint clamp  211  includes a first clamp  213  and a second clamp  215 . Joint clamp  211  includes a central shaft  217  as well as a turn-handle  219  for bringing first clamp  213  and second clamp  215  into a clamping position or into an unclamping position. Central shaft  217  includes a threaded portion  221  that mates with a second threaded portion (not shown) formed in the turn-handle  219 . As the turn-handle  219  is rotated, shaft  217  is drawn upwardly into the turn-handle  219  moving the two clamps  213 ,  215  together in order to perform the clamping function. 
         [0054]    First clamp  213  includes a passage  221  which is intended to accommodate, for example, post  17  of rail clamp  12  ( FIG. 2 ). Similarly, second clamp  215  includes a passage  223 . Passage  223  is intended to accommodate, for example, cross bar  18  ( FIG. 2 ). Passages  221 ,  223  may be shaped in an offset manner similar to passages  70 ,  72  as described above in relation to  FIG. 14 . 
         [0055]    Referring now to  FIG. 16 , a third multi-directional joint clamp  321  is shown. The third multi-directional joint clamp  321  may be implemented in a manner similar to the multi-directional joint clamp  21  of  FIGS. 3-14 . However, the joint clamp  321  of  FIG. 16  uses a different type of stop for the central shaft. In particular, the joint clamp  321  may include a central shaft  356  with an integral or fixed head  390  at its distal end instead of a nut. The head  390  may engage a shim  392 , which may adjust a distance D 2  between a top surface  391  of the washer  357  and a top surface  394  of the integral head  390 . A thicker shim  392  increases the distance D 2  and thereby increases the pressure load placed on the clamps  352 ,  354  by the cam lever  358  when in a clamping position since the length of the shaft  356  remains unchanged. Conversely, a thinner shim  392  decreases the distance D 2  and thereby decreases the pressure load placed on the clamps  352 ,  354 . Thus, a desired pressure load may be obtained by selecting a shim  392  having an appropriate thickness. The multi-directional joint clamp  21  of  FIGS. 3-14  may also adjust a pressure load applied by its cam lever  58 . However, the multi-directional joint clamp  21  may achieve such result by tightening or loosening the nut  113  instead of or in addition to using a shim  392 . 
         [0056]    While particular embodiments of the invention have been shown, it will be understood that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teaching. It is, therefore, the appended claims which define the true spirit and scope of the invention.