Needle assembly with removable depth stop

Abstract

A needle assembly ( 10 ) includes a needle ( 14 ) attached to mounting structure ( 12 ), and is used to insert the needle into the body of a patient. A depth stop unit ( 50 ) of the needle assembly provides a stop surface ( 58 ) to limit the distance the needle can be inserted into the body. The depth stop unit may include a depth stop ( 52 ) that is adjustable to selectively change the depth to which the needle can be inserted. The entire depth stop unit can be removed from the needle assembly to permit the full length of the needle to penetrate into the body.

1 . A convertible needle assembly ( 10 ) comprising: 
 a mounting structure ( 12 );    a needle ( 14 ) having a longitudinal axis and a sharp end ( 28 ,  32 ), the needle being mounted on the mounting structure and projecting outwardly from the mounting structure so that the sharp end is generally remote from the mounting structure;    a depth stop ( 52 ) adapted to limit the depth of penetration of the needle;    a rotary connector ( 66 ) adapted to releasably connect the depth stop to the needle assembly, the released depth stop being removable from the needle for increasing the possible depth of penetration of the needle.    
   
   
       2 . A convertible needle assembly as set forth in  claim 1  wherein the rotary connector ( 66 ) is constructed to connect to the mounting structure ( 12 ) by making a turn in a first direction about an axis that is less than 360 degrees, and to release from the mounting structure by making a turn in a second direction opposite the first direction about the axis that is less than 360 degrees.  
   
   
       3 . A convertible needle assembly as set forth in  claim 2  wherein the rotary connector ( 66 ) is constructed to connect to the mounting structure ( 12 ) and release from the mounting structure by making turns in the first and second directions, respectively, that are less than 180 degrees.  
   
   
       4 . A convertible needle assembly as set forth in  claim 2  wherein the rotary connector ( 66 ) is constructed to connect to the mounting structure ( 12 ) and release from the mounting structure by making turns in the first and second directions, respectively, that are about 90 degrees  
   
   
       5 . A convertible needle assembly as set forth in  claim 4  wherein the rotary connector ( 66 ) and mounting structure ( 12 ) are constructed for bayonet connection of the rotary connector to the mounting structure.  
   
   
       6 . A convertible needle assembly as set forth in  claim 5  wherein the mounting structure ( 12 ) comprises a pair of slots ( 80 ) and the rotary connector includes a pair of fingers ( 70 ) adapted to be received in the slots.  
   
   
       7 . A convertible needle assembly as set forth in  claim 6  wherein at least one of the slots ( 80 ) and the fingers ( 70 ) includes retention structure ( 70 A,  80 A) to resist relative rotation between the rotary connector ( 66 ) and the handle ( 12 ).  
   
   
       8 . A convertible needle assembly as set forth in  claim 7  wherein the retention structure comprises a projection ( 80 A) located in the slot ( 80 ) and a recess ( 70 A) located on the finger ( 70 ), the projection being adapted to snap into the recess to provide a tactile confirmation of engagement.  
   
   
       9 . A convertible needle assembly as set forth in  claim 1  wherein the rotary connector ( 66 ) mounts the depth stop ( 52 ) for selective positioning along the length of the needle ( 14 ) to change the depth limit of penetration.  
   
   
       10 . A convertible needle assembly as set forth in  claim 9  wherein the rotary connector ( 66 ) is elongate and has threads ( 64 ) along its length, the depth stop ( 52 ) having threads ( 76 ) mated with the threads of the rotary connector and being rotatable on the rotary connector for selective positioning along the length of the needle ( 14 ).  
   
   
       11 . A convertible needle assembly as set forth in  claim 10  wherein the rotary connector ( 66 ) and depth stop ( 52 ) are conjointly removable from the needle ( 14 ).  
   
   
       12 . A bone needle assembly ( 10 ) comprising: 
 a handle ( 12 );    a needle ( 14 ) having a longitudinal axis and a sharp end ( 28 ,  32 ), the needle being mounted on the handle at a location away from the sharp end of the needle and projecting outwardly from the handle;    a depth stop unit ( 50 ) comprising a positioning stem ( 62 ), a depth stop ( 52 ) mounted on the position stem and movable along a length of the stem to different selected positions along the stem and along the longitudinal axis of the needle, the depth stop having a stop surface ( 58 ) adapted to limit the depth of penetration of the needle, and a rotary connector ( 66 ) adapted to releasably connect the stem to the needle assembly, the rotary connector being capable of releasing connection of the stem so that the stem and depth stop may be removed from the needle for increasing the possible depth of penetration of the needle.    
   
   
       13 . A bone needle assembly as set forth in  claim 12  wherein the rotary connector ( 66 ) is constructed to connect to the handle ( 12 ) by making a turn in a first direction about an axis that is less than 360 degrees, and to release from the handle by making a turn in a second direction opposite the first direction about the axis that is less than 360 degrees.  
   
   
       14 . A bone needle assembly as set forth in  claim 13  wherein the rotary connector ( 66 ) is constructed to connect to the handle ( 12 ) and release from the handle by making turns in the first and second directions, respectively, that are about 90 degrees.  
   
   
       15 . A bone needle assembly as set forth in  claim 14  wherein the handle ( 12 ) includes a pair of slots ( 80 ) and the rotary connector ( 66 ) includes a pair of fingers ( 70 ) adapted to be received in the slots.  
   
   
       16 . A bone needle assembly as set forth in  claim 12  wherein the rotary connector ( 66 ) and positioning stem ( 62 ) are formed as one piece ( 60 ).  
   
   
       17 . A bone needle assembly as set forth in  claim 16  wherein the positioning stem ( 62 ) is elongate and has threads ( 64 ) along its length, the depth stop ( 52 ) having threads ( 76 ) mated with the threads of the positioning stem and being rotatable on the positioning stem for selective positioning along the length of the needle ( 14 ).  
   
   
       18 . A method of adjusting a permissible depth of penetration of a needle ( 14 ) of a needle assembly ( 10 ) comprising: 
 releasing a rotary connection of a depth stop unit ( 50 ) to the needle assembly, the depth stop unit including a depth stop ( 52 ) positioned along a longitudinal axis of the needle and limiting the depth of penetration of the needle to a first depth;    sliding the depth stop unit off of the needle to expose an additional length of the needle for penetration of the needle to a second depth greater than the first depth.    
   
   
       19 . A method as set forth in  claim 18  wherein the step of releasing connection of the depth stop unit ( 50 ) comprises rotating a rotary connector ( 66 ) attaching the depth stop unit to the needle assembly ( 10 ) less than 360 degrees relative to the needle assembly.  
   
   
       20 . A method as set forth in  claim 19  wherein the step of releasing the connection of the depth stop unit ( 50 ) comprises rotating the rotary connector ( 66 ) about 90 degrees relative to the needle assembly ( 10 ).