Abstract:
A trocar assembly includes a trocar housing having a blunt distal end and a proximal end; a blade assembly having a sharp tip and being slideable within the trocar housing between and armed position wherein the sharp tip extends distally beyond the blunt distal end and a relaxed position wherein the sharp tip is withdrawn proximally relative to the armed position; and a trigger member positioned relative to the housing to contact tissue when tissue is cut with the blade assembly in the armed position, and slideable by contact with the tissue to a proximal position which exposes the sharp tip and actuates a lock release member, the trigger member having member having a spring member biasing the trigger member distally so that removal of contact with the tissue allows the spring to move the trigger member distally, and further wherein distal movement of the trigger member with the lock release member activated releases the blade assembly from the armed position and allows the blade assembly to move to the relaxed position.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to what is known as a “safety trocar” which, in accordance with the present invention, has enhanced safety features and also has a lancet function. 
     As is well known in the industry, trocars are elongated sharp objects which are particularly used for making an incision in the course of surgical procedures, especially laparascopic and endoscopic procedures. 
     Such devices are used to penetrate the body wall, and thereby position a canula or tube through the body wall through which surgical instruments can be introduced for performing the desired surgical or medical procedures. 
     A long standing problem in the industry has been to provide suitable protection to underlying tissues and organs which might be damaged by an unshielded tip of a trocar. This problem is made more serious by virtue of the fact that the body wall gives substantial resistance to being pierced by the trocar, which then has the tendency to spring forward once the incision has been completed. 
     Many attempts have been made to provide suitable solutions to this problem. These various different attempts are too numerous to mention here. Nevertheless, despite these various efforts, the problem remains in the industry. 
     Based upon the foregoing, it is the primary object of the present invention to provide a trocar which has reliable and effective shielding and protection from injury to underlying organs and tissues. 
     It is a further object of the present invention to provide such a trocar which has additional functionality, specifically, in the form of a lancet. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, the foregoing objects and advantages have been readily attained. 
     According to the invention, a trocar is provided which has a longitudinally moveable blade and also a longitudinally moveable trigger/shield member. As will be set forth in detail in the description below, a button and triggering assembly are provided which allow for a series of different operational positions of the trocar. These include a relaxed position wherein the sharp blade member of the trocar is proximally positioned, with the sharp tip of the trocar positioned proximally of both a distal housing portion of the trocar and also the shield member. In this position, the blade cannot be exposed regardless of position of the shield, and the blade is therefore completely shielded. The blade is also positionable to an armed position, wherein the blade is positioned distally so as to position the tip of the blade beyond the blunt housing tip, but not beyond the tip of the shield member. When armed, the blade is held in this position by a releasable lock member. 
     The trigger/shield member is freely moveable between an extended position wherein it extends beyond the tip of the trocar blade, even in the armed position, and a rearward position wherein the blade in the armed position can be exposed. The trigger/shield member is associated with the lock mechanism so that rearward movement of the trigger/shield member engages a ratchet or other surface with the blade lock, and forward movement of the shield member disengages the blade lock and thereby provides for the blade to withdraw proximally into the housing of the trocar. 
     Thus, in accordance with present invention, rearward movement of the trigger member caused by contact with body tissue to be pierced, followed by forward movement of the trigger member as the trigger member forces through the opening, disengages the blade and causes the blade to be withdrawn proximally into the housing of the trocar as desired. In this way, the blade is positioned into a safe location as soon as the incision is completed. 
     In accordance with a further embodiment of the invention, the trigger member is never locked in a forward position, but is rather only biased toward that position. Thus, trauma and injury to underlying tissues and organs from the trigger is also prevented. 
     In further accordance with the invention, the blade can be manually positioned to a distal location which extends beyond the distal-most position of the shield, and in this configuration the device can be used as a lancet as desired. 
     The structures and positions as described above will be more thoroughly described in connection with the detailed description presented below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A detailed description of preferred embodiments of the present inventions follows, with reference to the attached drawings, wherein: 
         FIG. 1  shows a trocar in accordance with the present invention in a relaxed position; 
         FIG. 2  shows a trocar in accordance with the present invention in an armed position; 
         FIG. 3  shows a trocar in accordance with the present invention with the blade and shield in a cutting position; 
         FIGS. 4 and 5  show a trocar in accordance with the present invention wherein the triggering assembly is being actuated; 
         FIG. 6  shows a trocar in accordance with the present invention with the blade positioned in a lancet position; 
         FIG. 7  illustrates an enlarged portion of the trocar of the present invention with the housing removed to illustrate functioning of the triggering assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The invention relates to a shielded trocar with a lancet function. The trocar advantageously allows for enhanced shielding and security of the blade, and also allows for use of the blade as a lancet which broadens the usability of the surgical instrument as will be discussed below. Referring to the drawings, a preferred embodiment is illustrated. The drawings show sectional and to some extent perspective views to illustrate the details of the invention. 
       FIG. 1  shows a trocar  10  having a handle  12  positioned at a generally proximal end and a tip  14  positioned at a generally distal end. 
     According the invention, trocar  10  includes a substantially flat blade  16  which is slidably positioned relative to a tube or housing  18 . Blade  16  is mounted in a blade holder  20  which is also slidably positioned within tube  18 . A blade lock member  22  is pivotably mounted to blade holder  20 , and engagable in certain positions with tube  18  as will be discussed below. The entire assembly of blade  16 , blade holder  20  and blade lock member  22  are advantageously slidable within tube  18  and biased toward a proximal end of the device. 
     In further accordance with the invention, and still referring  FIG. 1 , trocar  10  also advantageously includes a a substantially flat shield/trigger member  24  which is also slidably mounted within tube  18 , and shield  24  is longitudinally connected to a lock release member  26 . Shield  24  and lock release member  26  are advantageously biased by a spring in a distal direction relative to tube  18 . 
     The assembly of blade  16 , blade holder  20  and blade lock  22  are moveable along the axis of tube  18  between a withdrawn position wherein the sharpened tip of blade  16  is positioned within the housing, an extended locked position wherein sharp tip of blade  16  extends beyond the housing but not beyond extended shield  24 , and a lancet position wherein the sharp tip of blade  16  is extended beyond the extended distal tip of shield  24 . 
     This slidable movement is, as set forth above, dictated by influence of a spring and also by a handle button  28  which receives a connecting post  30  as well as a connecting sleeve  32  which are in contact with blade holder  20  as shown in  FIG. 1 . 
     The assembly of shield member  24  and lock release member  26  are also advantageously axially moveable within tube  18 , and are biased toward a distal end of trocar  10  as discussed above. As will be discussed below, during use of trocar  10  to perform an incision, pressure is exerted upon shield  24  which causes shield  24  and lock release  26  to move proximally and allow the sharp tip of the blade in an armed position to be used for cutting. 
     Handle button  28  can advantageously be mounted within a proximally opening recess within a handle housing  34  for the device. Handle housing  34  can advantageously be shaped to fit comfortably within the hand of a user, and also preferably to mate with the housing of a canula (not shown) into which trocar  10  will be positioned. 
       FIG. 1  shows a spring  36  which advantageously can be positioned so as to exert force on blade holder  20  in a proximal direction and on shield  24  in a distal direction. This advantageously serves to bias both assemblies within tube  18  as desired. 
     Still further, a spring can advantageously be mounted to blade holder  20  for exerting a pivotable force on lock member  22 . This can advantageously be a coiled spring  38  which can be mounted to blade holder  20  with one arm  40  positioned between a spring block  42  and the back surface of a post holder  44  of blade holder  20 , and with a second arm  46  exerting a force on lock member  22 . 
     Trocar  10  still further advantageously includes two additional distal housing members  48 ,  50 , which support shield  24  and blade  16  respectively. 
     Distal housing members  48 ,  50  advantageously terminate in a blunt and rounded tip which is specifically designed and adapted to provide little or no risk of trauma or injury to any tissue which might contact same. Distal housing members  48 ,  50  advantageously mount with or are otherwise connected to tube  18  and distal housing members  48 ,  50  and tube  18  define the housing component of trocar  10  in accordance with the present invention. 
       FIGS. 2-5  illustrate the trocar of  FIG. 1  with the components in various different positions. 
     Specifically,  FIG. 2  shows trocar  10  with blade  16 , blade holder  20  and blade lock  22  locked in a distal armed position. In this position, lock  22  has a catch member  52  which is advantageously engaged against proximal movement, in this instance by extending into an opening or hole  54  in tube  18 . In this position, the sharp tip  56  of blade  16  extends beyond distal housing  48 ,  50 , but is still overlapped by shield member  24  as shown. Trocar  10  is positioned in this configuration by depressing button  28  sufficiently that lock  52  engages with the opening  54  in tube  18 , and this engagement is advantageously visible from exterior of tube  18  so that a user can readily know whether trocar  10  is armed. 
       FIG. 3  shows the trocar in a position which would be accomplished during a cutting procedure. During such a procedure, shield  24  is pushed proximally against the bias of spring  36  so as to expose sharp tip  56  which pierces and penetrates the tissue as desired. The proximal movement of shield  24  also proximally moves lock release member  26  so as to engage a tooth  58  of lock release member  26  behind a portion of blade lock  22  as shown in  FIG. 3 . 
       FIG. 4  shows the trocar of the present invention in a triggering position wherein the blade and shield have both now penetrated the body wall, and thus shield  24  is pushed distally by spring  36 . This distal movement of shield  24  positions shield  24  to again extend beyond the tip of blade  16  and causes lock release  26  to pivot lock  22  out of engagement with tube  18 . This is done by the distal movement of tooth  58  which causes trigger  22  to pivot relative to blade holder  20  in a clockwise motion and thereby disengage catch member or ridge  52  from the hole in tube  18 . 
     Turning to  FIG. 5 , this action of lock release member  26  and subsequent disengagement of lock member  22  from tube  18  results in a proximal movement of blade  16 , blade holder  20  and blade lock member  22  driven by spring  36  so as to withdraw the sharp tip of blade  16  to within distal housing members  48 ,  50 . It should be noted that when reference is made to the sharpened tip being “within” distal housing members  48 ,  50 , what is meant is that the entire cutting edge of blade  16  is positioned at least coincident and preferably proximally of the extending blunt tip defined by distal housing members  48 ,  50 . 
     From this position, it should be readily appreciated that absent depressing of button  28 , blade  16  is secured within the structure and cannot inflict any unintended damage to tissues and the like. 
     As set forth above, trocar  10  in accordance with present invention further has a lancet function which advantageously allows for blade  16  to be used to make cutting incisions as may be desired, regardless of the shield member. 
       FIG. 6  shows trocar  10  in this configuration, wherein a complete distal movement or depression of button  28  moves blade  16 , blade holder  20  and blade lock member  22  distally past the armed position to a position where the sharp tip  56  of blade  16  extends beyond shield  24 , even with shield  24  in the extended position. After the lancet function is completed, the trocar returns to the armed position as shown in  FIG. 2 , and can be used for subsequent procedures as desired. 
     In accordance with the present invention, the blade lock  22  and lock release member  26  are shown in further detail in  FIG. 7 . 
       FIG. 7  shows these components of trocar  10  in an enlarged manner and with tube  18  removed. Thus,  FIG. 7  shows blade holder  20  with blade lock member  22  pivotably mounted within a recess  60 . This mounting defines a pivot point or axis of rotation of blade lock member  22  relative to blade holder  20  around the pivot point defined by recess  60 . 
     Further as shown, lock release member  26  has tooth member  58  which is adapted to proximally slide past and catch a downwardly projecting ledge or surface  62  of blade lock member  22 . To this end, tooth  58  can advantageously have a gradually sloping surface, which increases in height in a generally distal direction, and which thereby allows easy proximal movement of tooth  58  past surface  62  as desired. 
       FIG. 7  also shows the other end connection of lock release member  26  with shield  24 , in this instance with a distal end  64  of lock release member  26  having an opening  66  into which a protruding post  68  of shield member  24  extends. In this way, shield  24  and lock release member  26  are axially mounted one relative to the other. Of course, shield  24  and lock release member  26  can be connected in other ways. 
     It should be appreciated that blade lock member  22  is shown in the drawings to be pivotably mounted relative to the blade assembly and pivotably mounted relative to the blade assembly and pivotable into engagement with housing  18 . The reverse could also be true, with pivotable mounting of lock member  22  to housing  18  and pivot to engage the blade assembly. 
     It should also be noted that trigger/shield member  24  serves primarily as a trigger to cause retraction of the blade following an incision. In addition, the tip of trigger/shield  24  is relatively blunt and dull so as to serve a shielding function as well. 
     It should be readily appreciated that the trocar in accordance with the present invention advantageously provides for secure and safe positioning of the trocar through the body wall of a surgical patient while providing extraordinary protection to underlying tissues and organs from accidental or unintended injury during the procedure. Still further, the trocar in accordance with the present invention has an advantageous lancet function which provides additional useful employment of the trocar in accordance with the present invention. 
     The present description has been given as an exemplary embodiment of the present invention. It should readily be appreciated that these various components of the device can and would be provided from materials known to a person of skill in the art to be suitable for the intended purpose and to a suitable scale also for the intended purpose. 
     It should also be appreciated that various modifications of the parts and assembly of the present invention can be made and would still fall well within the scope of the present invention. Thus, the scope of the invention is defined by the amended claims, and the description given herein is in all respects to be treated as one example of the broad scope of the invention.