Abstract:
An injection system comprising a tube having an inner diameter and an injection needle including a leading edge at one end thereof. A tapered surface is formed between a portion of the tube and the leading edge of the needle. The tapered surface provides a smooth transition surface from the tube to the needle, preventing the needle assembly from plugging when suspended particle materials are used in the injection system and allowing for easy and thorough cleaning of the needle for reuse and/or sterilization.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is directed generally to medical delivery systems. More particularly, the present invention is related to medical delivery systems that provide a smooth transition surface along which injectable materials can flow through the inside of a needle.  
         BACKGROUND OF THE INVENTION  
         [0002]    Medical delivery systems, such as those comprising syringe and needle assemblies, are commonly used for the purpose of injecting fluids into or withdrawing fluids from a body. These fluids may include medicine, blood or other types of biological materials.  
           [0003]    Although conventional medical delivery systems function in an adequate manner for a number of purposes, such systems currently include a number of limitations. For example, when injecting particles that are suspended in a gel carrier, the particles may lodge on the needle&#39;s leading edge or wall. If particles continue to collect in this location, the particles may eventually plug the passageway. If the passageway becomes plugged, the injection material and the particles contained therein are prevented from traveling down the needle and being placed into the body tissue.  
           [0004]    Additionally, in conventional injection systems there is often no seal of the flexible tubing to the needle at the needle&#39;s leading edge. For most flexible injection needles, the needle is bonded by adhesive or formed via molding into the flexible injection tubing. This allows for a varying or constant thickness gap to form at the needle&#39;s leading edge between the needle and the tubing; into which material can flow. The gap is closed off at the point the needle is actually sealed or bonded to the tubing, forming a single sided entrance/exit into the gap&#39;s containment (volume) created. In the case of materials with suspended particles, such as the tissue augmentation material described in U.S. Pat. No. 5,922,025 issued to Hubbard, a narrow gap may allow for the suspended particle carrier to flow into the gap but not the suspended particles. If there is enough carrier separation, the suspended particles will stop flowing, the needle will plug and the injection material will be prevented from being placed into the tissue. Also, this gap around the leading edge of the needle and its associated volume makes it impossible to thoroughly clean the needle because of the extreme difficulty in accessing the narrow gap.  
           [0005]    For most injection materials, such as liquid drugs, this gap and needle edge is not a major issue because the material flows much easier and does not contain suspended particles which can separate out. For injection materials that contain suspended particles, however, the above issues are much more of a concern.  
           [0006]    Prior art in FIGS.  1 - 3  show three conventional tube/needle connection designs. In each design, a needle  20  is sized to fit within a tube  22 . In prior art FIG. 1, an adhesive  28  is used to bond the needle  20  to the tube  22 . In prior art FIGS. 2 and 3, the tube  22  is formed such that a snug fit exists between the tube  22  and the needle  20 . In each of these cases, however, a leading edge  24  of the needle creates a “ledge” with the inner wall  26  of the tube  22 , resulting in a location where material is capable of collecting.  
         SUMMARY OF THE INVENTION  
         [0007]    It is therefore an object of the invention to provide an improved delivery system that provides a smooth transition from the system&#39;s tubing to the needle.  
           [0008]    It is another object of the invention to provide an improved delivery system that seals the needle&#39;s leading edge to the associated tubing.  
           [0009]    It is still another object of the invention to provide an improved delivery system where the full inside diameter of the needle can be cleaned and/or sterilized so that the needle can be reused.  
           [0010]    It is another object of the invention to provide an improved delivery system that permits a stylet to be easily inserted through the junction of the needle and the tubing.  
           [0011]    In accordance with the above objects, a medical injection system comprises a tube having an inner diameter, and an injection needle including a leading edge at one end thereof. A tapered surface is formed between a portion of the tube and the leading edge of the needle. The tapered surface provides a smooth transition surface from the tube to the needle, preventing the needle from plugging when suspended particle materials are used in the injection system and/or allows for easy cleaning of the inner diameter of the needle system. A variety of methods and arrangement can be used to form the tapered surface between the tube and the needle. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The foregoing advantages and features of the invention will become apparent upon reference to the following detailed description and the accompanying drawings, of which:  
         [0013]    [0013]FIG. 1 is a sectional side view of a first type of prior art tube/needle assembly;  
         [0014]    [0014]FIG. 2 is a sectional side view of a second type of prior art tube/needle assembly;  
         [0015]    [0015]FIG. 3 is a sectional side view of a third type of prior art tube/needle assembly;  
         [0016]    [0016]FIG. 4 is a sectional side view of a tube/needle assembly according to a first embodiment of the invention;  
         [0017]    [0017]FIG. 5 is a sectional side view of a tube/needle assembly according to a second embodiment of the invention;  
         [0018]    [0018]FIG. 6 is a sectional side view of a tube/needle assembly according to a third embodiment of the invention;  
         [0019]    [0019]FIG. 7 is a sectional side view of a tube/needle assembly according to a fourth embodiment of the invention;  
         [0020]    [0020]FIG. 8 is a sectional side view of a tube/needle assembly according to a fifth embodiment of the invention;;  
         [0021]    [0021]FIG. 9 is a sectional side view of a tube/needle assembly according to a sixth embodiment of the invention;  
         [0022]    [0022]FIG. 10 is a side view of a medical delivery system according to one embodiment of the invention with the syringe body separated from the needle assembly and  
         [0023]    [0023]FIG. 11 is a side view of the medical delivery system of FIG. 10 in the fully assembled position.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]    A tube/needle assembly constructed in accordance with the present invention is shown generally at  50  in FIGS.  4 - 9 . The tube/needle assembly  50  comprises a tube  22  coupled to a needle  20 . The tube  22  includes an inner surface  26 , while the needle  20  includes a leading edge  24  at one end thereof (see FIG.4), a diameter of the outer surface  36  and a diameter of an inner surface  38 . Depending upon the particular requirements of the application, the tube  22  could be flexible, semi-flexible or rigid. Stainless steel is one type of material which could be used to form a rigid tube  22 . In each of the embodiments shown in FIGS.  4 - 9 , the smooth transition is formed between the diameter of the inner surface  26  of the tube  22  and the diameter of the inner surface  38  of the needle  20 .  
         [0025]    A variety of mechanisms and structures can be used for forming a smooth transition between the diameter of the inner surface  26  of the tube  22  and the diameter of the inner surface  38  of the needle  20 . In FIG. 4, the tube  22  includes a transition portion  32  which results in a secondary inner surface  35  which diameter is smaller than the diameter of the inner surface  26  of the remainder of the tube  22 . The portion of the tube  22  that includes the secondary inner surface  35  also includes an indentation  25 . The indentation  25  is sized such that the needle  20  can fit therein with its leading edge  24  abutting against a portion of the tube  22 . As a result, the diameter of the inner surface  38  of the needle  20  is substantially identical in size to the secondary inner surface  35  of the tube  22 . By having a smooth transition between the tube  22  and the needle  20 , the likelihood of materials collecting near the leading edge  24  of the needle  20  decreases substantially.  
         [0026]    [0026]FIG. 7 is similar to FIG. 4 in that a portion of the needle  20  fits inside an indentation  25  of the tube  22 . In this embodiment, however, there is no transition portion  32  within the tube  22 , resulting in a single diameter of the inner surface  26  up until the indentation  25 . Nevertheless, the leading edge  24  of the needle  20  still substantially abuts against a portion of the tube  22 , resulting in a smooth transition between the diameter of the inner surface  26  of the tube and the diameter of the inner surface  38  of the needle  20 . In either of the embodiments shown in FIGS.  4  or  7 , the indentation  25  can be machined, formed or molded into the tube  22  before the needle  20  is inserted. The needle  20  may also be bonded or molded to the inside of the tube  22  if so desired.  
         [0027]    [0027]FIG. 5 shows another embodiment of the invention. In this embodiment, the diameter of the outer surface  36  of the needle  20  is substantially smaller than the diameter of the inner surface  26  of the tube  22 . An adhesive, such as epoxy, is used to bond the needle  20  to the inside of the tube  22 . The adhesive  28  is applied in the tube needle assembly  50  in a manner such where the tapered surface  34  is formed up to the leading edge  24  of the needle  20 . As a result, a smooth transition is formed from the diameter of the inner surface  26  of the tube across the tapered surface  34  of the adhesive  28  to the diameter of the inner surface  38  of the needle  20 .  
         [0028]    Another embodiment of the invention is shown in FIG. 6. In this particular embodiment, the diameter of the outer surface  36  of the needle  20  is substantially identical to the diameter of the inner surface  26  of the tube  22 . The leading edge  24  of the needle  20  is tapered to form a smooth transition between the inner surface  26  of the tube  22  and the inner surface  38  of the needle  20 .  
         [0029]    [0029]FIG. 8 shows yet another embodiment of the invention. In this embodiment, the diameter of an outer surface  29  of the tube  22  is substantially identical to the diameter of the inner surface  38  of the needle  20 . In this arrangement, the tube  22  is capable of being inserted directly into the inside of the needle  20 . Because the leading edge  24  of the needle  20  is located on the outside of the tube  22 , the leading edge  24  will not promote a collection or buildup of material inside the tube  22 .  
         [0030]    [0030]FIG. 9 shows still another embodiment of the invention. In the embodiment shown in FIG. 9, the tube  22  includes a transition portion  32  that leads to a reduced inner surface  33 , which defines a reduced portion  44  of the tube  22 . The reduced portion  44  of the tube  22  also includes a slot  40  formed therein. The slot  40  is sized to accept the leading edge  24  of the needle  20 . With the leading edge  24  and the needle  20  contained within the tube  22 , a smooth transition surface is formed which prevents material from collecting near the leading edge  24  of the needle  20 .  
         [0031]    As described above, the process used to manufacture the smooth transition surface from the inner surface  26  of the tube  22  to the inner surface  38  of the needle  20  can include a variety of forms. These include:  
         [0032]    1) using an adhesive or other similar material to form a taper, which covers the needle&#39;s leading edge; 2) machining, forming, or molding a taper and ledge in the end of the tubing, and then inserting and bonding the needle into the formed pocket; 3) directly molding the needle into the end of the tube 4) maintaining the inside tubing diameter the same as the inside needle diameter and providing a smooth transition from the tubing to the needle; 5) maintaining the tubing with an inside diameter approximately the same as the outside diameter of the needle and then tapering the inside of the needle to provide the smooth transition; 6) providing the tubing with an outside diameter approximately the same as the inside diameter of the needle and 7) various combinations of 1 through 6.  
         [0033]    A medical delivery or extraction system  60  constructed in accordance with the present invention is shown in FIGS. 10 and 11. The delivery or extraction system  60  comprises a syringe  62  and a needle assembly  76 . A syringe body  66  may accept a plunger (not shown) that is used to force fluid into or out of the syringe  62 . The syringe body  66  also includes a plurality of volume indicia  68  for measuring the amount of fluid inside the syringe  62  at any given moment. The syringe  62  includes an inner body  70  (shown in phantom in FIGS. 10 and 11) on the inside of the syringe  62 . The inner body  70  comprises a passageway through which the fluid primarily flows. The inner body  70  terminates at a connection portion  72 . In the area around the connection portion  72 , there are a plurality of threads  74  (shown in phantom) formed on the inside of the syringe body  66 . The needle assembly  76  comprises the needle  24  coupled to the tubing  22  which runs to a luer connection  78 . A stylet (not shown) can also be inserted into the needle assembly  76 . The luer connection  78  includes a hub  80  (shown in phantom) formed on the inside thereof. The hub  80  is used to mate the needle assembly  76  with the syringe  62 .  
         [0034]    The present invention can be used in conjunction in a variety of environments ranging from sterile hospital suites to non-sterile offices, primarily at ambient conditions. Additionally, the individual components could be color coded to an industry standard, indicating a particular feature, such as needle gauge of the product. The plastic tubing used can be manufactured from readily available extruded tubing known to those in the art. The needle  20  and associated components can be produced by current extrusion and fabrication methods such as grinding, drilling, cutting, milling, and polishing. The assembly of the tube/needle assembly  50  can be completed with standard assembly, forming, bonding, printing, and molding operations. The system can be packaged and sterilized using currently available methods.  
         [0035]    It should be understood that the above description of the invention and specific examples and embodiments, while indicating the preferred embodiments of the present invention, are given by demonstration and not limitation. For example, the tube/needle assembly  50  could be manufactured with any needle or flexible, semi flexible or rigid tubing size in which the suspended particles can flow through. An injection system according to the present invention may also include an adjustable outer sheath that covers the needle  20  that tapers and/or blends into the needle&#39;s tip during part of the injection procedure. Many changes and modifications within the scope of the present invention may therefore be made without departing from the spirit thereof and the present invention includes all such changes and modifications.