Abstract:
A system for retaining a tip protector on a needle having a curved portion or bend adjacent the tip. A Braun clip tip protector is used in combination with a small sleeve which fits around the needle such that it is free to slide towards the needle tip until stopped by the bend. In that stopped position, the tip protector covers the tip but cannot slide off the end of the needle.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates in general to needles with modified tips used for example in spinal injections, and specifically to a method of retaining a tip protector for such a needle.  
           [0003]    2. Description of the Related Art  
           [0004]    Historically in the medical field, needles have been necessary in many procedures. Unfortunately the danger of accidental injury by needles has increased due to the risk of transmission of various blood borne diseases such as AIDS and Hepatitis. In many procedures the use of needles has been reduced or eliminated, but there remain many situations in which the use of a needle is unavoidable. In these cases, it is desirable to limit the danger of accidental injury to people by the needle as much as possible.  
           [0005]    One such situation in which use of a needle has not been eliminated is the insertion of catheters into a patient&#39;s vein. The catheter is inserted into a patient&#39;s vein by a health care worker by using a handheld placement device which includes a sharp-tipped needle. The needle is positioned in the interior hollow portion of the catheter with its tip extending slightly beyond the edge of the catheter. The opposite end of the needle is connected to a hub which is capable of being held by the health care worker.  
           [0006]    Once the catheter has been inserted into the vein of the patient, the needle is withdrawn, leaving the catheter in the patient&#39;s vein. Once the needle has been removed from the catheter, however, the sharp tip of the needle is exposed, and poses a threat to anyone who handles it thereafter. With the needle tip exposed, the health care worker or anyone else who handles the needle is in danger of being accidentally pricked by the needle, and possibly infected with any blood-borne diseases the patient may have been carrying.  
           [0007]    Bent needles such as Huber, Husted, and Touhy needles may be used with similar catheters in procedures such as the injection of spinal anesthetics where it is desirable to keep tissue from being cored and jammed in the hollow tip of the needle. These needles are often used in conjunction with stylets which are inserted into the needle and block the opening in order to further help keep tissue from jamming the needle. The stylet is a thin, flexible rod with a tip shaped such that it provides a flat surface at the opening of the needle. A hub at the end opposite the tip may be grasped and used to remove the stylet from the hollow interior of the Huber or other needle.  
           [0008]    Many tip protectors have been developed for straight catheter needles. One in particular as described in patent publication WO 99/08742 (also U.S. application Ser. No. 08/097,170) to Wynkoop et al. describes a tip protector commercially referred to as the “Braun clip.” The Braun clip was developed for use with over-the-needle intra-venous catheters as described above. This particular device is adapted to fit within the hub of the catheter such that when the needle is withdrawn from inside the catheter, the Braun clip slides toward the sharp tip until it reaches a retaining element which holds the clip from sliding completely off the tip. The retaining element is positioned to stop the clip such that its shielding portion covers the sharp tip of the needle.  
           [0009]    When used with a typical I.V. catheter needle, the Braun clip is retained from sliding off the end of the needle by crimping the needle near the sharp tip. Unfortunately, needles such as the Huber which are often used in conjunction with stylets cannot be crimped due to the need for free movement of the stylet within the space inside the hollow needle. Thus, it is desirable to have a method of retaining a tip protector on a needle with a bent tip such as a Huber needle.  
         SUMMARY OF THE INVENTION  
         [0010]    It is therefore an object of the present invention to provide a method of retaining a tip protector on a needle with a bent or otherwise modified tip which does not involve crimping or otherwise altering the profile of the needle.  
           [0011]    The present invention employs a tip protector device having a protector portion and a portion that slides on the needle but cannot slide past the needle bend and stops the protector portion in the desired protective position. In the present invention a preferred form of the slide portion includes a sleeve with an internal diameter slightly larger than the needle&#39;s outer diameter. The sleeve slides freely over the majority of the needle shaft, but not around the needle bend and off the end of the tip. The protector portion can be of a known clip type such as the Braun clip.  
           [0012]    The length of the sleeve is also an important dimension. It should be such that the Braun clip is allowed to operate properly without falling off the end of the tip. If the sleeve is too long, the clip will be restrained from closing over the needle tip. If the sleeve is too short, it may slide around the bend and off the tip. The details of these dimensions and relationships are expanded in the detailed description below.  
           [0013]    One advantage of the use of a sleeve as described herein is its ease of assembly. Once the sleeve has been properly sized, it can be easily slid onto the shaft of the needle in operative relationship with the Braun clip before attaching the needle hub or before bending the tip. Another advantage is the low cost of the part. A sleeve providing features and advantages of the present invention can be produced very economically.  
           [0014]    When used with an over-the-needle catheter, the tip protector and the sleeve can initially be conveniently housed in a rear hub on the catheter.  
           [0015]    For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.  
           [0016]    All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a side view of a Huber needle illustrating its curvature.  
         [0018]    [0018]FIG. 2 is a front view of the Huber needle of FIG. 1 showing a stylet as it is typically positioned within the needle.  
         [0019]    [0019]FIG. 3 is an orthogonal view of a Braun clip tip protector.  
         [0020]    [0020]FIG. 4 is a side view of a tip protector and retaining sleeve positioned along the shaft of the needle, and having features and advantages of the present invention.  
         [0021]    [0021]FIG. 5 is a side view of a tip protector and retaining sleeve positioned so as to cover the sharp needle tip, and having features and advantages of the present invention.  
         [0022]    [0022]FIG. 6 illustrates an alternate relationship between the sleeve and a tip protector.  
         [0023]    [0023]FIG. 7 is a side view of the device of FIGS. 4 and 5 in combination with an over-the-needle catheter. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]    [0024]FIGS. 1 and 2 show a Huber needle  32  characterized by a curve or bend  20  in the tip. The bend allows the edge  38  of the opening  34  at the tip of the needle to be parallel to the axis of the needle  32 . This helps to prevent tissue from being cored, and lodged in the hollow needle, and thereby clogging it. This type of needle is typically used in cases when a health care provider needs to inject fluids, sometimes including drugs, into areas protected by substantially hard tissues, such as the spine or the chest.  
         [0025]    In order to additionally guard against tissue being cored by the needle, a Huber needle is typically used with a stylet  30  as shown in FIG. 2. The stylet  30  is typically a small, flexible rod which slides into the hollow interior of the needle  32 . The tip of the stylet  30  is typically ground to a flat face  36  which is substantially co-planar with the edge  38  surrounding the opening  34  of the needle  32 . The features and advantages of the present invention may also be realized in association with other types of needles with bent tips, such as Husted or Touhy needles. These are typically differentiated by the degree of their respective bends, and the present invention may be practiced with these other needles in the same manner as with the Huber needle.  
         [0026]    An over-the-needle catheter  62  like the one shown in FIG. 7 is typically used to inject fluids, often containing medicines into the body of a patient. Over-the needle catheters are typically formed from relatively flexible plastics, and are typically disposed on a straight metal needle which is used to pierce the skin and any other tissue in order to locate the open end of the catheter in the particular part of the body to which the fluids are to be delivered. In typical use, a Huber needle  32  with an over-the-needle catheter  62  is grasped by the handle  71  and inserted for example, into the spine. Once the health care provider has determined that the tip  18  of the needle  32  and catheter  62  are in the correct location, the needle  32  is withdrawn from the patient (not shown), leaving the catheter  62  in the desired location. According to the present invention, when the needle  32  is withdrawn, a tip protector  10  and retaining slide or sleeve  12  preferably contained within the hub  60  of the catheter  62  will preferably be slid to the tip  18  of the needle  32  and stop, thereby covering the sharp tip  18  and protecting anyone handling the needle  32  from injury.  
         [0027]    [0027]FIG. 3 shows a Braun clip  10  preferably punched from a substantially resilient material which will allow the clip to be substantially “springy” when used as described herein, and then bent into the shape shown. Alternatively, the clip  10  may be machined or cast, or made by any other process known to those skilled in the art. The hole  14  in the base  13  of the clip  10  is preferably sized such that it will fit over the needle  32  and allow the clip  10  to slide freely along the needle  32 . The distance from the base  13  and the shielding portion  22  of the clip  10  can be considered the operative length of the clip  10 . The Braun clip  10  is schematically shown and described herein, and reference can also be made to pending U.S. application Ser. No. 08/097,170 (also WO 99/08742) which is incorporated herein by reference.  
         [0028]    [0028]FIGS. 4 and 5 illustrate the Braun clip tip protector  10  and the retaining sleeve  12  as they are preferably disposed relative to one another and the needle  32  in accordance with the present invention. In FIG. 5 the shielding portion  22  of the clip  10  is covering the sharp tip  18  of the needle  32 .  
         [0029]    The retaining sleeve  12  preferably has a substantially circular cross section. Alternatively, the sleeve  12  may have any one of a variety of cross-sectional shapes such as elliptical, triangular, square, or any other polygonal shape providing that it functions as described herein. The retaining sleeve  12  may be made from a variety of substantially rigid materials, such as metal, glass, or substantially rigid polymers.  
         [0030]    The size of the retaining sleeve  12  is preferably determined by the gauge of the needle  32 , the size and angle of the bend  20 , and the size of the clip  10  being used. The inner diameter of the retaining sleeve  12  is preferably . 0001  to . 003  inch larger than the outer diameter of the needle  32 . If the inner diameter of the sleeve  12  is too small, the sleeve  12  of course will not slide properly. Conversely, if it is too large, the sleeve  12  will be allowed to slide past the bend  20  of the needle  32 , thus allowing the clip  10  to fall off and thereby failing to protect a person from the sharp needle tip  18 . The outer diameter of the sleeve  12  is preferably larger than the hole  14  in the base  13  of the clip  10  (shown in FIG. 3).  
         [0031]    The sleeve  12  is preferably long enough that it is unable to slide around the bend  20  in the needle  32 , but short enough that it allows the shielding portion  22  of the clip  10  to close over the sharp tip of the needle  32 . The clip  10  is also preferably restrained from sliding far enough over the tip that the flanges  50  (shown in FIG. 3) pass the sharp tip  18  as this would allow the tip to be exposed.  
         [0032]    Referring to FIG. 5, the relationship between the various dimensions of the clip  10  and the sleeve  12  are important to obtain the described result. Proper dimensions are preferably chosen based on the gauge of the needle  32  and the degree and length of the bend  20 . The clip  10  and sleeve  12  are also preferably sized relative to one-another such that they will perform as described herein. For example, the distance between the sharp tip  18  of the needle  32  and the sleeve bottom end  70 , when the sleeve  12  reaches the position at which it is stopped by the bend  20 , should correspond with the operative length of the Braun clip  10  in such a way that the two lengths are substantially equal to one another (as shown in FIG. 5). The operative length of the clip  10  being defined as the distance between the clip base  13  and the shielding portion  22  of the clip  10 .  
         [0033]    The sleeve  12  is preferably held in operative relation to the clip  10  by the geometry of the clip  10  itself, and is preferably not physically attached thereto. If desired, however, the sleeve  12  may be glued, welded, or otherwise permanently bonded to the clip  10  in the operative relationship shown and described herein. Alternatively, the clip  10  and sleeve  12  may be formed integrally from the same piece of material by machining, casting, or any other method known to those skilled in the art.  
         [0034]    In an alternative embodiment as shown in FIG. 6, the sleeve  12  may be attached to the underside  76  of the base  13  of the clip  10 . In this embodiment, the operative length of the clip  10  should be substantially equal to the distance between the end of the sleeve  12  attached to the clip underside  76  and the sharp tip  18  when the sleeve  12  is in its stopped position. Thus, with a sleeve and clip dimensioned like that of FIG. 5, the needle bend would have to be spaced further from the tip. Of course, clip and sleeve dimensions can be changed to fit a particular curved needle. The sleeve may be bonded with a weld, glue or other known method, and it is preferably made from a substantially rigid material such as plastic, metal, glass, etc. This embodiment is useful when the bent section of the needle is particularly long.  
         [0035]    Thus, it may be seen that in either arrangement of FIGS.  5  or  6 , the sleeve  12  and the clip  10  are configured to interengage in a manner that the sleeve stops movement of the clip in a position in which the clip shielding portion  22  properly covers the needle tip.  
         [0036]    [0036]FIG. 7 illustrates a Braun clip-type protector  10  with a retaining sleeve  12  and an over-the-needle catheter  62  in typical use. The Braun clip  10  and the appropriately positioned retaining sleeve  12  are preferably contained within the hub  60  of the catheter  62  and positioned at the base  52  of the needle  32  while the needle  32  and catheter  62  are being inserted into the patient. When the needle  32  is withdrawn, the tip protector  10  and retaining sleeve  12  slide along the shaft  16  of the needle  32  toward the tip  18  of the needle  32 . When the tip protector  10  and retaining sleeve  12  reach the position shown in FIG. 5, the retaining sleeve  12  is preferably stopped by the bend  20  in the needle  32 . The stopped sleeve  12  in turn preferably stops the sliding of the clip  10  by contact between the two at the clip base  13 . In this position (as shown in FIG. 5), the shielding portion  22  of the Braun clip  10  covers the sharp tip  18  of the needle  32  in order to guard a person from being accidentally injured.  
         [0037]    If desired, the clip  10  can be disengaged, and both parts  10  and  12  may be slid back down to the base  38  of the needle  32 , and a catheter  62  may be replaced. In order to move the clip  10  from the position shown in FIG. 5 to that shown in FIG. 4, the health care provider may pinch the sides  15  of the clip  10  until the two sides of the shielding portion  22  are sufficiently separated that they will allow the clip  10  to slide over the tip  18  and down the shaft  16  of the needle.  
         [0038]    As will be recognized by those skilled in the art, the features and advantages of the present invention may be realized in association with any tip protector with which the invention is compatible, and are not limited to the Braun clip tip protector.  
         [0039]    Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.