Abstract:
A shielded bladed obturator is provided with a shield lockout that prevents retraction of a shield to expose a blade for cutting. The shield lockout in one aspect has a rotational switch interacting with a longitudinal extending shield to lock and unlock the shield. A blade exposure and coverage system is also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 11/744,108, filed May 3, 2007, that claims the benefit of U.S. Provisional Application No. 60/746,313, filed May 3, 2006, the disclosures of which are hereby incorporated by reference as if set forth in full herein. This application also claims the benefit of U.S. Provisional Application No. 60/912,679, filed Apr. 18, 2007, the disclosure of which is hereby incorporated by reference as if set forth in full herein. 
    
    
     BACKGROUND 
     This invention relates generally to trocars or access ports used in endoscopic or laparoscopic surgeries and more particularly, to flat blade shielded obturators. 
     A surgical access port or trocar generally has a cannula and a valve housing coupled to one end of the cannula and an obturator inserted into the cannula has a shaft with a sharp blade or tip at one end of the shaft. In operation, the trocar cannula extends across a body wall, e.g., the abdominal wall, providing access into a body cavity, such as the abdominal cavity. The obturator facilitates the placement of the trocar by puncturing and/or penetrating the tissue forming the body wall. 
     In one example, the obturator is inserted through the cannula and its sharp bladed tip extends beyond one end of the cannula. The sharp bladed tip of the obturator cuts tissue as the trocar and obturator are moved through the body wall. Once the trocar and obturator are operatively positioned, the obturator can be removed from the trocar body leaving the cannula to provide working-channel access into the body cavity. 
     With the body wall penetrated, the sharp bladed tip can be covered or protected. For example, a spring-loaded tubular safety shield which surrounds the shaft of the obturator may move forward to cover the tip of the obturator once resistance to the movement of the safety shield, e.g., from the body wall, is removed. As such, the cutting stops once the body wall has been penetrated. However, a relatively large force may be required to cause the tip of an obturator to penetrate the body wall. Once the tip penetrates the body wall, resistance to penetration is removed and the tip of the obturator is suddenly free to reach into the body cavity and cause additional cutting. Failure to stop this cutting action can result in complications. Obturators having spring-loaded tubular safety shields may require larger incisions and may require considerable time to move the shield to cover the tip, the shield possessing a relatively large mass. 
     SUMMARY 
     Generally, a flat blade shielded obturator is provided. A shield lockout is provided that facilitates assembly, enhances reliability and reduces complex mechanisms. In one aspect, an obturator comprises a handle having a switch movable from a first, locked position to a second, unlocked position. The switch has a first section and a second section. Connected to the handle, the obturator also has a shaft having a movable portion and a fixed portion with a blade connected to the fixed portion of the shaft. The shaft has a longitudinal axis. The switch in the first position has the first section of the switch obstructing the movable portion of the shaft to prevent movement of the movable portion of the shaft along the longitudinal axis. In the second position, the switch has the second section of the switch obstructing the movable portion of the shaft and allowing movement of the movable portion of the shaft along the longitudinal axis. 
     In one aspect, the first section of the switch is a first arm coupled to a user accessible tab and the second section of the switch is a second arm smaller than the first arm. The second arm is deflectable in a direction parallel to the longitudinal axis of the shaft. The first arm is not deflectable. The user accessible tab and first section may be movable to the second position with the user accessible tab returning to the first position while the first section remains in the second position. The obturator may have a wall within the handle that is exposed when the switch is moved to the second position. The second section is movable along a direction parallel to the longitudinal axis. The first section is not movable along a direction parallel to the longitudinal axis. The first and second sections are rotatable about a longitudinal axis offset from and parallel to the longitudinal axis of the shaft. The obturator further comprises a ramp obstructing movement of the switch in the second position and allowing movement of the switch in the first position. The ramp has a first, low profile end and a second, high profile end. The second section of the switch is adapted to ride along the ramp while deflecting and to snap into a locked position along a back wall of the ramp, juxtaposed to the high profile end of the ramp, thereby locking the switch into the second position. The second section may be a spring. The second section may be more resilient than the first section. 
     Many of the attendant features of the present invention will be more readily appreciated as the same becomes better understood by reference to the foregoing and following description and considered in connection with the accompanying drawings in which like reference symbols designate like parts throughout. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a trocar system in accordance with various aspects of the present invention; 
         FIG. 2  is a perspective view of a trocar system in accordance with various aspects of the present invention; 
         FIG. 3  is a side view of a distal portion of an obturator of a trocar system in accordance with various aspects of the present invention; 
         FIG. 4  is a side view of a distal portion of an obturator of a trocar system in accordance with various aspects of the present invention; 
         FIG. 5  is a perspective view of a proximal portion of an obturator in accordance with various aspects of the present invention; 
         FIG. 6  is a perspective view of a proximal portion of an obturator in accordance with various aspects of the present invention; 
         FIG. 7  is a perspective view of a proximal portion of an obturator in accordance with various aspects of the present invention; 
         FIG. 8  is a perspective view of a proximal portion of an obturator in accordance with various aspects of the present invention; 
         FIG. 9  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIG. 10  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIG. 11  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIG. 12  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIG. 13  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIGS. 14   a - 14   c  depict top views of an obturator in accordance with various aspects of the present invention; 
         FIGS. 15   a - 15   d  depict side views of an obturator in accordance with various aspects of the present invention; 
         FIGS. 16   a - 16   d  depict side views, in cross section, of the obturator of  FIGS. 15   a - 15   d;    
         FIG. 17  is a perspective view of an obturator in accordance with various aspects of the present invention; 
         FIG. 18  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIG. 19  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIG. 20   a  is a top view of an obturator in accordance with various aspects of the present invention; 
         FIGS. 20   b - 20   d  depict perspective views of a proximal portion of an obturator in accordance with various aspects of the present invention; 
         FIGS. 21   a - 21   f  depict perspective views of a proximal portion of an obturator in accordance with various aspects of the present invention; and 
         FIG. 22  is a perspective view of an obturator in accordance with various aspects of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIGS. 1-13 , an obturator  50  has a handle  60  and a shaft  70 . The handle  60  has a switch  100  movable from a first, locked position to a second, unlocked position. The switch  100  has a first section, or arm  106 , and a second section, or arm  116 , each extending from a pivot post  114 . The shaft  70  is connected to the handle  60  and has a longitudinal axis. The shaft  70  has a movable portion, or shield  102 , and a fixed portion  72 . A blade  104  is connected to a distal portion  74  of the fixed portion  72  of the shaft  70  and extends distally beyond a distal end  76  of the fixed portion of the shaft. The movable portion  102  of the shaft  70  functions as a blade shield and is movable between a first, distal position, wherein it inhibits contact with the blade  104  to prevent cutting, to a second, proximal position, wherein the blade is exposed for cutting. With the switch  100  in the first, locked position, the first section  106  of the switch obstructs the shield portion  102  of the shaft  70  to prevent movement of the shield along the longitudinal axis. With the switch  100  in the second, unlocked position, the second section  116  of the switch obstructs the shield  102 , but allows the shield to move proximally along the longitudinal axis, thereby exposing the blade  104 . 
     As indicated above, the switch  100  is manipulated by a user, e.g., a surgeon, to manually unlock the movable portion, or shield  102  of the shaft  70 , allowing the blade shield to travel proximally, thereby exposing the blade  104  for cutting. The movable portion  102  of the shaft  70  has a shield shaft  110  that is adapted to move proximally into the handle  60  of the obturator  50 . When the switch  100  is in the locked position ( FIG. 1 ), it overlaps a proximal end  108  of a shield shaft  110  which extends through a center of a base plate  112 . 
     The switch  106  is rotatable about a pivot post  114  mounted on the base plate  112  offset from the longitudinal axis of the shaft. As the switch  106  rotates to unlock the shield  102 , the proximal end  108  of the shield shaft  110  is unobstructed and allowed to retract proximally into the handle  100  ( FIG. 2 ). The switch  100  is held in the unlocked position by the second arm  116  of the switch. The second arm  116 , which is deflectable in a direction parallel to the longitudinal axis of the shaft  70 , locks on the back side  118  of a ramp  120  extending from the base plate  112 . More particularly, the ramp  120  has a first, low profile end  140  and a second, high profile end  142 . The second arm  116  of the switch  100  is adapted to ride along the ramp  120  while deflecting and to snap into a locked position along the back side  118  of the ramp, which is juxtaposed to the high profile end of the ramp, thereby locking the switch into the second position. The ramp  120  obstructs movement of the switch  100  in the second position and allows movement of the switch in the second position. While the second arm  116  is deflectable, the first arm  106  is not deflectable. 
     When the trocar assembly  122  is inserted through an abdominal wall, the shield  102  retracts due to insertion pressure on the distal tip  124  of the shield. The proximal end  108  of the shield shaft  110  makes contact with the second arm  116  which is locked on the back wall  118  of the base plate ramp  120 . As contact is made, the shield shaft  110  lifts the second arm  116  up over the ramp  120  releasing the switch  100 . A torsion spring  126  connected between the base plate  112  and switch  100  forces the switch back to its original position. However, the switch  100  stops short as the first arm  106  of the switch is biased against the proximal end  108  of the shield shaft  110  while the shield  102  is retracted during insertion. As the obturator  128  clears the inside edge of the abdominal wall, the shield  102 , which is compressing a compression spring  130  ( FIG. 22 ) between itself and the base plate  112 , is allowed to extend back forward to a shielded position, thereby preventing the blade  104  from performing additional cutting. As the proximal end  108  of the shield shaft  110  moves distally beyond contact with the second arm  116  of the switch, the shield shaft releases or no longer obstructs the spring loaded switch  100 , thereby allowing the switch to return back to its original, locked position ( FIG. 1 ). 
     In one aspect, a torsion  126  ( FIG. 9 ), extension  132  ( FIG. 12 ), compression (not shown), or flat spring  134  ( FIG. 13 ) is provided to bias the switch  100  to an initial position. The switch  106  and spring, in one aspect, is combined into one part where the spring is a wire form or single molded configuration that forms the switch, the torsion spring, and the second arm (not shown). In one aspect, the switch  136  is a single piece and the spring  138  (a wire form or single molded piece) incorporates the second arm ( FIGS. 14   a - 14   c ). 
     In  FIGS. 15   a - 15   d  and  16   a - 16   d , a slide switch  200  is utilized. The switch  200  has a clearance hole  202  in the center for the shield shaft  204 . The hole  202  in the switch  200  is offset ( FIGS. 15   a  and  16   a ), which locks the shield, i.e., preventing retraction of the shield. As the switch  200  is slid to one side ( FIGS. 15   b  and  16   b ), the switch hooks onto a fixed latch  206 , unlocking the shield. The hole  202  in the switch  200  is now aligned with the shield shaft  204  and the shield shaft is free to retract. As the shield shaft  204  retracts, a projection  208 , extending from the shield shaft, contacts the switch  200  ( FIGS. 15   c  and  16   c ). The switch  200  is lifted, which disengages the switch from the fixed latch  206  ( FIGS. 15   d  and  16   d ). An extension spring  210  pulls the switch  200  to resist disengagement of the switch from the fixed latch  206 . As the shield shaft  204  extends back to its original position, the switch  200 , under spring force, returns back to its locked position ( FIG. 15   a ). 
     Referring to  FIGS. 17-22 , in one aspect, a multiple piece switch  300  is utilized. As such, after being moved to an unlocked position ( FIG. 19 ), if a portion or component of the switch  300  accessible by a user were interfered or blocked, other portions of the switch continue to operate and thus the shield  302  can be re-locked after use. The switch  300  has a first section, or arm  318 , a second section, or arm  332 , and a third section, or tab portion  324  having a tab  342  and a tab arm  344 . In  FIG. 18 , the switch  300  is in an initial or resting state. A torsion spring  306  is assembled on the same pivotal post  308  as the switch  300 . Switch  300  is rotatable about a longitudinal axis offset from and parallel to the longitudinal axis of the shaft  338 . A first leg  310  of the torsion spring  306  will rest against the base plate  312  along the flat surface  314  to the upper right of the post  308  in  FIG. 18 . A second leg  316  of the torsion spring  306  will rest against the first arm  318  ( FIG. 19 ) of the switch to keep the tab portion  324  pressed against the wall  320  when in this state. The wall  320  is exposed when the tab portion  324  of the switch is moved to the second position. A spring, such as a leaf spring  322 , coupled to the tab portion  324  of the switch  300 , is not pre-loaded, but rests along the female portion of the boss pin (not shown) attached to the cover  326 . The leaf spring  322  may be formed integrally with the tab portion  324  to facilitate manufacturability and assembly of the switch  300 . 
     In  FIG. 19 , as the user slides the tab  342  to rotate the switch  300  to unlock the blade shield  302  ( FIG. 17 ), the tab presses against the first arm  318  of the switch at the flat interface  328 , such that the tab, first arm  318  and second arm  332  of the switch rotate together. This causes the thin second arm  332  of the switch  300  to move or deflect up the ramp  334  and hook the back side  340  of the ramp. The second arm  332  is movable or deflectable along a direction parallel to the longitudinal axis of the shaft  338 , while the first arm  318  is not deflectable. More particularly, the ramp  334  has a first, low profile end  348  and a second, high profile end  350 . The second arm  332  of the switch  300  is adapted to ride along the ramp  334  while deflecting and to snap into a locked position along the back side  340  of the ramp, which is juxtaposed to the high profile end of the ramp, thereby locking the switch into the second position. The ramp  334  obstructs movement of the switch  300  in the second position and allows movement of the switch in the first position. The leaf spring  322  on the tab portion  324  of the switch  300  is now compressed and deformed against the cover boss pin. This causes a small moment on the tab portion  324  in the clockwise direction. 
     Once the user ceases to apply a load to the switch  300  (i.e., removes his or her finger from the tab  342 ), the tab portion  324  will automatically return to a nearly closed position ( FIG. 20   a ) while the first arm  318  remains in the second position. In this state, the locking mechanism is disabled or unlocked. The blade shield  302  is free to move, allowing the blade  336  to cut. As the blade shield  302  retracts far enough to expose the blade  336  for cutting, the proximal end  346  of the shaft  338  forces the second arm  332  of the switch  300  over the ramp  334 . The torsion spring  306  will force the first arm  318  and second arm  332  of the switch  300  clockwise, back into the locked position against the proximal end  346  of the shield shaft  338  until the compression spring  130  pushes the shield  302  toward covering the blade  336 , in which the second arm  332  of the switch  300  resets back to its original, locked position ( FIG. 18 ). Meanwhile, the tap portion  324  remains stationary in this nearly closed position to prevent the user from interfering with the locking mechanism. 
     Accordingly, the present invention provides a bladed shielded obturator. Although this invention has been described in certain specific embodiments, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise than specifically described, including various changes in the size, shape and materials, without departing from the scope and spirit of the present invention. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive, the scope of the present invention to be determined by the appended claims and their equivalents rather than the foregoing description.