Abstract:
One embodiment is directed to a method for safe injection, comprising: providing an injection assembly and inserting a plunger tip of the injection assembly to a final insertion state and releasing an associated manual insertion load. A retraction load developed sufficient to cause the plunger tip to be proximally withdrawn pulls the retractable needle proximally relative to the needle housing to a retracted state wherein a distal tip of the needle becomes mechanically locked into an encapsulated configuration wherein it is no longer exposed for injection.

Description:
RELATED APPLICATION DATA 
     The present application claims the benefit under 35 U.S.C. §119 to U.S. provisional patent application Ser. No. 61/841,702 filed Jul. 1, 2013. The foregoing application is hereby incorporated by reference into the present application in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to injection systems, devices, and processes for facilitating various levels of control over fluid infusion, and more particularly to systems and methods related to safety syringes in healthcare environments. 
     BACKGROUND 
     Millions of syringes, such as that depicted in  FIG. 1A  ( 2 ), are consumed in healthcare environments every day. A typical syringe ( 2 ) comprises a tubular body ( 4 ), a plunger ( 6 ), and an injection needle ( 8 ). As shown in  FIG. 1B , such a syringe ( 2 ) may be utilized not only to inject fluid into a patient, but also to withdraw or expel fluid out of or into a container such as a medicine bottle, vial, bag, or other drug containment system ( 10 ). Indeed, due to regulatory constraints in some countries such as the United States as well as sterility maintenance concerns, upon use of a medicine bottle ( 10 ) with a syringe ( 2 ) as shown in a particular patient&#39;s environment, such medicine bottle may only be utilized with a single patient and then must be disposed of—causing significant medical waste from bottle and remaining medicine disposal, and even contributing to periodic shortages of certain critical drugs. Referring to  FIG. 2A , three Luer-type syringes ( 12 ) are depicted, each having a Luer fitting geometry ( 14 ) disposed distally, so that they may be coupled with other devices having similar mating geometry, such as the Luer manifold assembly ( 16 ) depicted in  FIG. 2B . The Luer fittings ( 14 ) of the syringes of  FIG. 2A  may be termed the “male” Luer fittings, while those of  FIG. 2B  ( 18 ) may be termed the “female” Luer fittings; one of the Luer interfaces may be threaded (in which case the configuration may be referred to as a “Luer lock” configuration) so that the two sides may be coupled by relative rotation, which may be combined with compressive loading. In other words, in one Luer lock embodiment, rotation, possibly along with compression, may be utilized to engage threads within the male fitting which are configured to engage a flange on the female fitting and bring the devices together into a fluid-sealed coupling. In another embodiment, tapered interfacing geometries may be utilized to provide for a Luer engagement using compression without threads or rotation (such a configuration may be referred to as a “slip-on” or “conical” Luer configuration). While such Luer couplings are perceived to be relatively safe for operators, there is risk of medicine spilling/leaking and parts breakage during the loading to provide a Luer coupling. The use of needle injection configurations, on the other hand, carries with it the risk of a sharp needle contacting or poking a person or structure that is not desired. For this reason, so called “safety syringes” have been developed. 
     One embodiment of a safety syringe ( 20 ) is shown in  FIG. 3 , wherein a tubular shield member ( 22 ) is spring biased to cover the needle ( 8 ) when released from a locked position relative to the syringe body ( 4 ). Another embodiment of a safety syringe ( 24 ) is shown in  FIGS. 4A-4B . With such a configuration, after full insertion of the plunger ( 6 ) relative to the syringe body ( 4 ), the retractable needle ( 26 ) is configured to retract ( 28 ) back to a safe position within the tubular body ( 4 ), as shown in  FIG. 4B . Such a configuration which is configured to collapse upon itself may be associated with blood spatter/aerosolization problems, the safe storage of pre-loaded energy which may possible malfunction and activate before desirable, loss of accuracy in giving full-dose injections due to residual dead space within the spring compression volume, and/or loss of retraction velocity control which may be associated with pain and patient anxiety. 
     Further complicating the syringe marketplace is an increasing demand for pre-filled syringe assemblies such as that depicted in  FIG. 5A , which generally comprise a syringe body, or “drug enclosure containment delivery system”, ( 34 ), a plunger tip, plug, or stopper ( 36 ), and a distal seal or cap ( 35 ) which may be fitted over a Luer type interface. Liquid medicine may reside in the volume, or medicine reservoir, ( 40 ) between the distal seal and the distal end ( 37 ) of the plunger tip ( 36 ). Such assemblies are desirable because they may be standardized and produced with precision in volume by the few manufacturers in the world who can afford to meet all of the continually changing regulations of the world for filling, packaging, and medicine/drug interfacing materials selection and component use. Such simple configurations, however, generally will not meet the new world standards for single-use, safety, auto-disabling, and anti-needle-stick. Thus certain suppliers have moved to more “vertical” solutions, such as that ( 41 ) featured in  FIG. 5B , which attempts to meet all of the standards, or at least a portion thereof, with one solution; as a result of trying to meet these standards for many different scenarios, such products may have significant limitations (including some of those described above in reference to  FIGS. 3-4B ) and relatively high inventory and utilization expenses. 
     There is a need for improved injection systems which address the shortcomings of currently-available configurations. In particular, there is a need for safety injection solutions which may utilize the existing and relatively well-controlled supply chain of conventionally delivered pre-filled syringe assemblies such as that described in reference to  FIG. 5A . 
     SUMMARY OF THE INVENTION 
     One embodiment is directed to a method for safe injection, comprising: providing an injection assembly having a syringe body removably intercoupled between a needle assembly, plunger tip, and plunger control assembly, wherein the syringe body forms a fluid reservoir and has proximal and distal ends, the plunger tip is positioned within the fluid reservoir in a configuration such that medicinal fluid may be contained within the fluid reservoir, the needle assembly is removably coupleable to the distal end of the syringe body such that the medicinal fluid may be transferred through a retractable needle coupled to a needle housing comprising the needle assembly upon insertion of the plunger tip relative to the syringe body, and the plunger control assembly is coupled to the plunger tip and configured to facilitate manual insertion of the plunger tip relative to the syringe body; and inserting the plunger tip to a final insertion state and releasing an associated manual insertion load, developing a retraction load sufficient to cause the plunger tip to be proximally withdrawn, pulling the retractable needle proximally relative to the needle housing to a retracted state wherein a distal tip of the needle becomes mechanically locked into an encapsulated configuration wherein it is no longer exposed for injection. The fluid reservoir may comprise a substantially cylindrical volume. The syringe body may comprise a glass material. The syringe body may comprise a polymeric material. The plunger tip may comprise an elastomeric material. The elastomeric material may comprise a butyl-based rubber. The needle may be a hypodermic needle. The hypodermic needle may comprise a standard size between about 20 gauge and about 34 gauge. The needle assembly may comprise a movable needle insertion-preventing member configured to prevent re-insertion of the needle relative to the syringe body after the needle has been placed in the retracted state. The insertion-preventing member may be configured to move along an axis that is substantially perpendicular to a longitudinal axis of the needle. The method further may comprise removing a fixing constraint from the insertion-preventing member when the plunger tip reaches the final insertion state with a releasing member operatively coupled to the insertion-preventing member. The releasing member may comprise a push member configured to be compressively loaded when the plunger tip is urged into the final insertion state. The push member may be configured to release a mechanical latch that is configured to hold the needle fixed in place relative to the syringe body, thereby releasing the needle such that it may be proximally withdrawn into the retracted state. The mechanical latch may be configured to interface directly with the needle. The mechanical latch may be configured to interface with a needle interfacing member that is interfaced directly with the needle. The needle interfacing member may comprise a compliant O-ring. The method further may comprise coupling a plunger tip coupler member to the plunger tip. Coupling the plunger tip coupler member may comprise inserting one or more helical threads defined into the plunger tip coupler member into the plunger tip. The method further may comprise resisting retraction of the plunger tip before the plunger tip has been inserted to the final insertion state for the first time. 
     Another embodiment is directed to a method for safe injection, comprising: inserting a plunger tip of a syringe assembly with an inserting load to inject with a needle medicinal fluid which may be contained within a syringe body forming a reservoir into which the plunger tip is movably coupled; and upon insertion of the plunger tip to a final insertion state at the end of the reservoir, releasing the plunger tip from the inserting load to allow a vacuum load developed during inserting to retract the needle to a retracted state wherein a distal tip of the needle becomes mechanically locked into an encapsulated configuration wherein it is no longer exposed for injection. The method further may comprise resisting retraction of the plunger tip before the plunger tip has been inserted to the final insertion state for the first time. The retraction load may be a vacuum load within the fluid reservoir. The retraction load may be a spring load. The retraction load may be manually applied. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-5B  illustrate various aspects of conventional injection syringe configurations. 
         FIGS. 6-10K  illustrate various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 11  illustrates a process for conducting an injection procedure utilizing a safety syringe configuration such as that described in reference to  FIGS. 6-10K . 
         FIGS. 12A-12G  illustrate various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 13  illustrates a process for conducting an injection procedure utilizing a safety syringe configuration such as that described in reference to  FIGS. 12A-12G . 
         FIGS. 14A-14G  illustrate various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 15  illustrates a process for conducting an injection procedure utilizing a safety syringe configuration such as that described in reference to  FIGS. 14A-14G . 
         FIGS. 16A-16H  illustrate various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 17  illustrates a process for conducting an injection procedure utilizing a safety syringe configuration such as that described in reference to  FIGS. 16A-16H . 
         FIGS. 18A-18I  illustrate various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 19  illustrates a process for conducting an injection procedure utilizing a safety syringe configuration such as that described in reference to  FIGS. 18A-18I . 
         FIGS. 20A-20I  illustrate various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 21  illustrates a process for conducting an injection procedure utilizing a safety syringe configuration such as that described in reference to  FIGS. 20A-20I . 
         FIGS. 22A-22K  illustrate various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 23  illustrates various aspects of a safety syringe configuration in accordance with the present invention. 
         FIG. 24  illustrates various aspects of a safety syringe configuration in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 6 , a disassembled view of a safety syringe assembly is illustrated, comprising a needle assembly ( 32 ) which may be removably coupled to an off-the-shelf syringe body ( 34 ) forming a reservoir ( 40 ) which may be at least partially pre-filled with a fluid such as a liquid medicine product. The distal end of the syringe body is configured to have a Luer type coupling interface ( 42 ), while the proximal end of the syringe body comprises a conventional syringe flange ( 38 ), such as that known as a “Gerresheimer” flange configuration. The syringe body ( 34 ) preferably comprises a translucent material such as a glass or polymer. To form a contained volume within the reservoir ( 40 ), and to assist with expulsion of the associated fluid through the needle, a plunger tip ( 36 ) may be positioned within the syringe body ( 34 ). The syringe body may define a substantially cylindrical shape (i.e., so that a plunger tip  36  having a circular cross sectional shape may establish a seal against the syringe body), or be configured to have other cross sectional shapes, such as an ellipse. A plunger control assembly ( 44 ) is configured to be coupled to the syringe body and to engage the plunger tip ( 36 ) to assist in expelling fluid from the syringe through the needle and in withdrawing the needle, as described below. As described above, the syringe body flange ( 38 ) may comprise a conventional flanged geometry which may be selected from the syringe body supplier; preferably the plunger control assembly ( 44 ) may be configured to be coupleable to many of the conventionally-available flange ( 38 ) geometries, such as various sizes of the flanges available from suppliers such as Gerresheimer, as noted above. The plunger tip ( 36 ) may comprise a standard butyl rubber material and may be coated, such as with a biocompatible lubricious coating, to facilitate preferred sealing and relative motion characteristics against the associated syringe body structure and material. 
     Referring to  FIG. 7A , an exploded orthogonal view of an embodiment of a needle assembly ( 32 ) is illustrated showing a needle cover ( 46 ) configured to form a cover or shield over at least the distal end of the needle ( 58 ) when assembled. A distal needle housing member ( 48 ) and proximal needle housing member ( 50 ) assist in maintaining the position of the needle relative to the syringe body, and in controlling movement of a latch mechanism that comprises a two-fingered latch member ( 54 ) movably coupled to a movable needle insertion preventing member ( 56 ). The needle member has a sharpened distal end ( 58 ) configured to be inserted in a hypodermic fashion into a tissue structure of a patient; a proximal end ( 60 ) comprises a proximal tip interface ( 62 ) that may be configured to stab into and couple to a portion of an associated plunger tip, in a fashion that somewhat mimics the function of a harpoon instrument. 
     Referring to  FIG. 7A , an exploded orthogonal view of an embodiment of a plunger control assembly ( 44 ) is illustrated showing a plunger insertion member ( 74 ) intercoupling a distally-disposed plunger tip coupler member ( 64 ), which may have outer helical threads configured to “screw into” and couple to the compliant material of an associated plunger tip as desired, a plunger insertion member proximal manipulation interface ( 76 ), a brake member ( 68 ), and a sealing flange assembly ( 66 ) comprising a flange member ( 72 ) configured to be removably coupled to the proximal flange fitting of a conventional syringe body (such as that shown in  FIG. 6  as element  38 ) to hold into place a syringe body proximal plug member ( 88 ) with an additional sealing interface comprising an O-ring ( 70 ) to facilitate the buildup of a vacuum load when an associated plunger tip is inserted relative to the sealing flange assembly ( 88 ). The plunger insertion member proximal manipulation interface ( 76 ) preferably is shaped to allow for finger and/or thumb manipulation in a manner akin to that associated with operation of a conventional syringe (i.e., depression with a thumb or finger while one or more other fingers/digits are utilized to apply a counterload at the flange area).  FIG. 8  illustrates a partially assembled configuration wherein a syringe body has been coupled to a plunger control assembly ( 44 ) with the plunger tip coupler member ( 64 ) helically advanced and coupled into the proximal aspect of the compliant plunger tip ( 36 ), and the flange member ( 72 ) coupled to the proximal flanged aspect of the syringe body ( 34 ). The needle cover ( 46 ) preferably is configured to shield/cover not only the distal aspect of the needle member ( 58 ), but also the proximal aspect ( 60 ,  62 ), in the depicted configuration, as shown, to enable an operator to manually grasp the needle assembly ( 32 ) as shown and couple it to the distal aspect of the syringe body ( 34 ) without placing the operator&#39;s fingers at risk for an accidental needle puncturing. 
     Referring to  FIG. 9A , the fairly large overlap between the distal end ( 80 ) of the syringe body outer diameter and the interfacing end ( 78 ) of the needle cover provides a relatively large geometric guidance surface for aligning the needle proximal end ( 60 ) as it is guided through the needle assembly components during assembly/coupling with the syringe body ( 34 ) and guided into fluidic contact with the fluid reservoir of the syringe body ( 34 ). 
     Referring to  FIG. 9B , a flange member ( 72 ) is shown in relation to an intercoupled syringe body ( 34 ) and plunger insertion member ( 74 ). In the depicted embodiment, the mechanical interface between the plunger insertion member ( 74 ) and the flange member ( 72 ) is a brake member or brake assembly ( 68 ) which is configured to be snap-fitted into a recess formed into the flange member ( 72 ).  FIG. 9C  illustrates an opposing orthogonal view.  FIG. 9D  illustrates a flange member ( 72 ) without the brake member in place to show the recess surface ( 86 ) formed into the flange member ( 72 ).  FIG. 9E  shows a brake member ( 68 ) having two outer mounting release tabs ( 82 ) and two inner braking tabs ( 84 ). In this embodiment, the brake member ( 68 ) is configured to be snapped into the flange member recess ( 86 ) and held in place by geometric features coupled to the outer mounting release tabs ( 82 ). In such a position, the two inner braking tabs ( 84 ) are geometrically biased toward the distal end of the syringe body so that they will easily cantilever away from an inserted (i.e., inserted through the two inner braking tabs  84 ) plunger insertion member (element  74  in other drawings; not shown in  FIGS. 9D and 9E ) during such insertion with relatively low friction—but also resist retraction of the same plunger insertion member with relatively high loads until released from the coupling to the flange member ( 72 ). Such a release may be accomplished by depressing the two outer mounting release tabs ( 82 )—and, indeed, these tabs ( 82 ) are configured to be automatically depressed for such a release upon full insertion of the plunger insertion member to a final insertion state wherein the associated plunger tip is interfaced against the end of the syringe and wherein the plunger insertion member proximal interface (element  76  in  FIG. 7B , for example) is interfaced against the outer mounting release tabs ( 82 ) such that they are released, and the braking member ( 68 ) is allowed to travel along with the plunger insertion member, as shown in  FIG. 10I , without further resisting retraction of the associated plunger insertion member. 
     Referring to  FIG. 10A-10K , various operational aspects of one embodiment of a safety syringe configuration in accordance with the present invention are illustrated. Referring to  FIG. 10A , with a needle assembly coupled to a syringe body ( 34 ), the protective needle cover ( 46 ) may be removed as shown to expose the distal portion of the needle ( 58 ) for injection into a tissue structure of a patient. The internal support mechanisms of the needle assembly may be configured to support an injection load of about 5 pounds without yielding or slipping—to meet a standard such as those promulgated by organizations such as ISO. In the depicted embodiment, the proximal end ( 60 ) of the needle is configured to extend into the fluid reservoir ( 40 ) of the syringe body to become a fluid conduit for injection into a tissue structure that may be temporarily interfaced with a distal portion ( 58 ) of the needle. The needle is threaded through a movable needle insertion preventing member ( 56 ) which imparts only very minimal frictional loads to the needle in the depicted configuration wherein the needle is threaded directly through the needle insertion preventing member ( 56 ). Referring to the close-up view of  FIG. 10B , with full insertion of the plunger tip to a final insertion state, the plunger is configured to impart a compressive load upon the needle and/or a sleeve coupled thereto, to urge the movable needle insertion preventing member ( 56 ) against the two fingers of the clip or latch member ( 54 ), thereby urging them away from each other ( 90 ). The geometry and structural moduli of these structures may be configured such that upon full insertion of the plunger tip to a final insertion state, a geometric step (element  110  as illustrated in  FIG. 10C ) of the movable needle insertion preventing member ( 56 ) is pushed past the two fingers of the latch member ( 54 ) so that the movable needle insertion preventing member ( 56 ) is stuck in a position, by virtue of the ramp surfaces (element  108  as illustrated in  FIG. 10C ), wherein it will remain biased open—and also biased to move in a direction (parallel to the axis  96  illustrated in  FIG. 10D ) substantially perpendicular to the longitudinal axis of the needle (element  98  in  FIG. 10D , for example) if freed from the constraint of the needle passing through it. The movable needle insertion preventing member ( 56 ) may be slidably interfaced against, and retained by in the axial direction parallel to the longitudinal axis of the needle ( 98 ), a wall ( 112 ) formed in the distal needle housing member ( 48 ), as shown in  FIG. 10D . With the two fingers of the latch member ( 54 ) biased open, a needle axial position constraining step ( 102 ) formed in the needle and/or a sleeve coupled to the needle may be freed from the constraint of the latch member ( 54 ) and allowed to retract, as shown in  FIG. 10D , wherein the two latch contact points ( 92 ,  94 ) have been pulled apart enough that the needle is being withdrawn, here by vacuum load built up within the proximal aspect of the syringe body during insertion of the plunger tip.  FIGS. 10E and 10F  illustrate sequential images wherein the movable needle insertion preventing member ( 56 ) has been pushed past the two latch member ( 54 ) fingers to leave them permanently relatively open to that the needle may be retracted. Referring to  FIG. 10G , with sufficient retraction of the needle so that the needle tip ( 58 ) is no longer threaded through a first needle through-aperture ( 104 ) and constraining the motion of the movable needle insertion preventing member ( 56 ), the movable needle insertion preventing member ( 56 ) is urged by compressive loading of the latch member ( 54 ) fingers on the ramped geometry of the movable needle insertion preventing member ( 56 ) to move along the depicted axis ( 96 ) which is substantially perpendicular to the needle longitudinal axis ( 98 ), thereby placing the needle distal tip ( 58 ) in alignment with the partial-depth needle aperture ( 106 ), which is configured to specifically block and constrain the needle distal tip ( 58 ) as a successive attempt is made to try to insert the needle.  FIGS. 10H-10J  illustrate various aspects of the plunger control assembly in relation to the syringe body ( 34 ). Referring to  FIG. 10 k   , upon full retraction of the needle into the body of the syringe ( 34 ), the needle may be allowed to rest, or be biased to rest, in a canted or intentionally misaligned position relative to the syringe body ( 34 ) to prevent re-insertion of the needle relative to the syringe body ( 34 ). In use, the embodiments featured in  FIGS. 10A-10K  may function as follows: an off-the-shelf pre-filled syringe body, such as that described in reference to  FIG. 5A , may be coupled to a plunger control assembly and needle assembly near the intended use location; the protective needle cover may be removed, and the patient injected with the needle, followed by insertion of the plunger tip to expel the syringe fluid into the patient; as the plunger tip is seated into the distal end of the syringe body, several events are intended to occur: a) the proximal end of the needle is harpooned into the plunger tip to couple these two structures; b) a plunger retraction brake is released by interfacing of the plunger insertion member proximal interface and brake member outer tabs so that the plunger insertion member and intercoupled plunger tip and harpooned needle may be withdrawn relative to the syringe body; c) a vacuum load is maintained by a substantially sealed proximal volume between the flange assembly ( 66 ) and the plunger tip which is expanded as the plunger tip is inserted; d) a movable needle retraction-preventing member ( 56 ) urges open the fingers of the associated latch member ( 54 ) to allow the needle to become relatively unconstrained in terms of proximal retraction or withdrawal into/toward the syringe body—and upon enough retraction of the needle (i.e. via the vacuum load pulling the plunger tip, which is harpoon-coupled to the needle so that the needle is pulled along proximally into retraction), the movable needle retraction-preventing member ( 56 ) moves over to block further re-insertion of the needle tip. Thus a single-use safety syringe configuration is described wherein a single injecting insertion is made relatively simple, while various mechanisms interact to allow for a controlled retraction of the needle and prevention of re-insertion after retraction. During the injecting insertion, the braking member of the plunger control assembly allows an operator to remove his hands completely from the system while the brake retains the position of the plunger tip relative to the syringe body. The braking member also may be effective in retaining the geometric relationship between a plunger tip and an associated syringe body and captured pre-filled medicine volume during shipping and handling before utilization. For example, with conventional configurations, such as that shown in  FIG. 5A , it is possible that changes in pressure, such as those created with air transport, may move the plunger tip relative to the syringe body—possibly past the acceptable sterile geometric boundaries/barriers. Such relative motion may be prevented with a locking/braking configuration as described herein. 
     Referring to  FIG. 11 , a process is illustrated for using an embodiment such as that described in reference to  FIGS. 10A-10K . After preoperative diagnostics and patient preparation ( 200 ), an safety syringe injection assembly may be assembled ( 202 ). When an injection is desired, the protective needle cover may be removed ( 204 ) and the injection performed upon a tissue structure of the patient ( 206 ,  208 ). After the plunger tip has reached a final insertion state, the built up vacuum load may be utilized to assist in withdrawing the plunger tip proximally to a retracted state ( 210 ); such insertion to the final insertion state and subsequent retraction of the needle may cause movement of the movable needle insertion-preventing member to move into a configuration wherein it will prevent re-insertion of the needle ( 212 ); insertion of the plunger tip to the final insertion state also causes the plunger braking member to mechanically transition to an un-braked state wherein plunger retraction is not mechanically resisted by the brake ( 214 ). The retracted needle may be fully retracted into the syringe body and positioned in a canted configuration to prevent further insertion ( 216 ). 
     Referring to  FIGS. 12A-12G , another embodiment is depicted wherein a mechanism is configured to allow for a full injection insertion, after which the needle may be automatically withdrawn, and in certain embodiments, also prevented from re-insertion. For simplicity of illustration, braking features, such as those described in reference to  FIGS. 9A-10K , are not shown in the embodiments of  FIGS. 12A-12G , but they may be present in certain variations and configurations, and are described, for example, in the embodiment of  FIG. 13 . 
     Referring to  FIGS. 12A-12G , a safety syringe assembly is depicted wherein a needle housing ( 120 ) may be coupled to a conventional syringe body ( 34 ) and utilized to facilitate a single full insertion of the needle, after which needle withdrawal may be automatically facilitated by a combination of a withdrawal-prevention mechanism converting to a state wherein needle withdrawal is freely allowed, and a vacuum load developed in the captured volume proximal to the plunger tip in the syringe body being allowed to facilitate needle withdrawal, as described above. As shown in  FIG. 12A , a plunger tip ( 36 ) is shown ready to inject the contents of the syringe body ( 34 ) into the needle, the distal portion ( 58 ) of which may be directly interfaced with a patient tissue structure. Referring to  FIG. 12B , a close-up view of which is shown in  FIG. 12D , with the plunger tip ( 36 ) almost fully inserted, the needle remains locked in place and prevented from withdrawal by a locking configuration comprising an O-ring forcibly urged against a needle sleeve ( 126 ) coupled to the needle. The proximal needle end ( 60 ) features a harpoon-like interface ( 64 ) configured to stab into the plunger tip ( 36 ) material and couple thereto. The depicted embodiment also features a polymeric backing ( 122 ) of the plunger tip ( 36 ) selected to create a more robust coupling of the needle and plunger tip. Referring to  FIG. 12C , a close-up view of which is shown in  FIG. 12E , with complete insertion of the plunger tip ( 36 ), the needle sleeve ( 126 ) urges a load-transferring member ( 128 ) at least partway through a plurality of latch members ( 130 ,  131 ), which rotate ( 132 ) as shown in  FIG. 12E , to release an O-ring loading member ( 134 ) from its prior constraint up against the O-ring ( 170 ), allowing the O-ring to slightly relax and thereby free the needle of the previous axial withdrawal constraint, after which retraction of the plunger insertion member ( 74 ), such as by vacuum load or manually, will pull the needle into proximal withdrawal relative to the syringe body ( 34 ), as shown in  FIGS. 12F and 12G . 
     Referring to  FIG. 13 , an embodiment similar to that of  FIG. 11  is illustrated, with the exception that in the embodiment of  FIG. 13 , after the injection insertion ( 208 ), insertion to a final insertion state releases compression of an O-ring from against the needle, thereby allowing the needle to be withdrawn ( 218 ), as described above in reference to  FIGS. 12A-12G . 
     Referring to  FIGS. 14A-14G , an embodiment similar to that of  FIGS. 12A-12G  is illustrated, with the exception that the embodiment of  FIGS. 14A-14G  features an off-axis or bent proximal harpooning or barb interface ( 136 ) that is configured to cause a fully-withdrawn needle to be canted to the side, or out of alignment relative to the syringe body ( 34 ), so that the needle cannot be re-inserted by another attempted insertion of the plunger tip.  FIG. 15 , which is similar to  FIG. 13 , features the addition of such misalignment of the needle member upon full withdrawal of the needle member into the syringe body ( 220 ) to prevent re-insertion of the needle member relative to the syringe body (i.e., to prevent re-use, or accidental/undesired contact of a needle tip with a person or object). 
     Referring to  FIGS. 16A-16H , an embodiment similar to that of  FIGS. 12A-12G  is illustrated, with the exception that the embodiment of  FIGS. 16A-16H  features double off-axis or bent proximal harpooning or barb interface ( 138 ) that is configured to cause a fully-withdrawn needle to be canted to the side, or out of alignment relative to the syringe body ( 34 ), so that the needle cannot be re-inserted by another attempted insertion of the plunger tip—and also to provide an even more robust harpoon-style coupling between the proximal portion of the needle ( 60 ) and the plunger tip ( 36 ).  FIG. 17 , which is similar to  FIG. 13 , features the addition of such misalignment of the needle member upon full withdrawal of the needle member into the syringe body using the twin coupling member ( 222 ) to prevent re-insertion of the needle member relative to the syringe body (i.e., to prevent re-use, or accidental/undesired contact of a needle tip with a person or object). 
     Referring to  FIGS. 18A-18I , an embodiment similar to that of  FIGS. 12A-12G  is illustrated, with the exception that the embodiment of  FIGS. 18A-18I  features a quite different mechanism for allowing insertion of the needle and resisting retraction until full insertion of the needle, after which retraction of the needle is facilitated by deformation of a clip member ( 140 ). For example, referring to the close-up views of  FIGS. 18D and 18E , in  FIG. 18D , a close-up view of the configuration of  FIG. 18A , the clip member ( 140 ), with two through-apertures ( 142 ,  144 ) that are slightly out of alignment, prevents movement of the needle ( 58 ) relative to the syringe body ( 34 ).  FIG. 18E  shows the plunger tip almost fully, but not fully, inserted relative to the syringe body, as in  FIG. 18B . Upon full insertion of the plunger tip ( 36 ), as in  FIGS. 18C and 18F , a needle sleeve member, or a step formed in the outer geometry of the needle, compresses the clip member ( 140 ), causing the apertures ( 142 ,  144 ) to become more aligned, if not completely aligned, after which they may be held in such configuration by a feature ( 148 ) formed into the needle housing ( 120 ) configured to retain such configuration so that the needle may be withdrawn, such as by a manually applied load or vacuum load, as described above. In other words, the clip member ( 140 ) may be squeezed by virtue of a physical coupling through the needle assembly to the plunger tip ( 36 ), causing deformation (which may be configured to be plastic deformation or elastic deformation, depending upon the materials and dimensions selected for the clip; in an elastic deformation configuration, the holding feature  148  assists more prominently in retaining the deformed shape of the clip) of the clip ( 140 ) to a shape such as that shown in  FIG. 18F , wherein the needle ( 58 ) is allowed to retract without substantial resistance from the clip, due to alignment of the apertures of the clip.  FIG. 18H  shows an incomplete withdrawal of the needle into the syringe body;  FIG. 18I  shows a complete withdrawal of the needle into the syringe body, with canting of the withdrawn needle to the side to prevent further insertion of the needle relative to the syringe body, as described above. The embodiment of  FIG. 19  is similar to that of  FIG. 15 , with the exception that the embodiment of  FIG. 19  features deformation of a needle retraction resistance clip, thereby allowing the needle to be withdrawn ( 224 ). 
     Referring to  FIGS. 20A-20I , an embodiment similar to that of  FIGS. 12A-12G  is illustrated, with the exception that the embodiment of  FIGS. 20A-20I  features a quite different mechanism for resisting needle retraction until full insertion of the needle, after which retraction of the needle is facilitated by movement of a cantilevered latch member ( 152 ) of a latch assembly ( 150 ) coupled to the distal needle housing ( 120 ). For example, referring to the close-up views of  FIGS. 20D and 20E , in  FIG. 20D , a close-up view of the configuration of  FIG. 20A , the latch member ( 152 ) prevents withdrawal of the of the needle ( 58 ) relative to the syringe body ( 34 ) by interfacing with a recess ( 154 ) formed into the needle or a sleeve member coupled thereto.  FIG. 20E  shows the plunger tip almost fully, but not fully, inserted relative to the syringe body, as in  FIG. 20B . Upon full insertion of the plunger tip ( 36 ), as in  FIGS. 20C and 20F , the needle and/or needle sleeve ( 156 ) member is advanced slightly forward, dislodging the latch member ( 152 ) from the recess ( 154 ), after which the needle may be withdrawn (such as is shown in  FIG. 20G ), such as by a manually applied load or vacuum load, as described above.  FIG. 20H  shows an incomplete withdrawal of the needle into the syringe body;  FIG. 20I  shows a complete withdrawal of the needle into the syringe body, with canting of the withdrawn needle to the side to prevent further insertion of the needle relative to the syringe body, as described above. The embodiment of  FIG. 21  is similar to that of  FIG. 19 , with the exception that the embodiment of  FIG. 21  features mechanical reconfiguration of a needle retraction resistance latch, thereby allowing the needle to be withdrawn ( 226 ). 
     Referring to  FIGS. 22A-22K , an embodiment is depicted wherein a needle assembly features a proximally disposed intercoupling member ( 160 ) configured to be coupled (via relative rotation) to a distal Luer fitting ( 14 ) of a conventional syringe assembly, and also configured to be coupled (also via relative rotation—preferably the same rotational direction as the first rotation) to an inner surface of the needle housing ( 166 ) in a manner wherein the proximal aspect ( 60 ,  64 ) of the needle remain shielded from the hands of an operator, or from other objects. Referring to  FIG. 22A , the needle assembly comprises a needle coupled through a needle housing ( 166 ) and intercoupled intercoupling member ( 160 ) so that the proximal end of the needle ( 60 ,  64 ) does not extend beyond the proximal end of the intercoupling member ( 160 ). A removable needle shield ( 158 ) isolates the distal portion ( 58 ) of the needle and is removable at injection time; further, the removable needle shield ( 158 ) features rotational manipulation features, such as small wing features, to facilitate easy rotation of the needle assembly relative to the syringe body ( 34 ) to which it is to be coupled. Such features may be particularly useful for the home healthcare market wherein patients suffering from maladies such as arthritis may desire to use syringes for injection and have difficulty without physical feature aids. Referring to  FIG. 22B , the syringe assembly and needle assembly are placed into contact with the Luer interface of the intercoupling member ( 160 ) positioned against the Luer interface of the syringe assembly. With twisting engagement, the intercoupling begins via the intercoupling member ( 160 ), as shown in the cross sectional view of  FIG. 22C . With further twisting, the proximal coupling interface ( 164 ) of the intercoupling member ( 160 ) causes closer engagement of the intercoupling member ( 160 ) using the inner helical thread interface ( 168 ) of the needle housing—until the coupling is complete, as shown in  FIGS. 22D and 22E . Subsequently the removable needle shield ( 158 ) may be removed and an injection of fluid started, as shown in  FIGS. 22F and 22G . Upon full insertion of the plunger tip ( 36 ) relative to the syringe body ( 34 ), the proximal needle harpooning interface ( 64 ) may be coupled to the plunger tip ( 36 ), and an un-latching configuration similar to that shown in reference to  FIGS. 20A-201  may allow for proximal withdrawal of the needle, as shown in  FIGS. 22I-22K . 
     Referring to  FIG. 23 , a configuration similar to that depicted in  FIG. 12A  is illustrated, with exception that the configuration of  FIG. 23  features an integrated spring member ( 51 ) intercoupled between the needle member ( 58 ) and the distal end of the syringe body ( 34 ) to provide a needle retraction load sufficient to retract the needle, as described above—but in the context of a vacuum retraction load. 
     Referring to  FIG. 24 , a configuration similar to that depicted in  FIG. 12A  is illustrated, with exception that the configuration of  FIG. 23  features an integrated spring member ( 101 ) intercoupled between the proximal end ( 38 ) of the syringe body ( 34 ) and the proximal end of the plunger insertion member ( 74 ) to provide a needle retraction load sufficient to retract the needle, as described above—but in the context of a vacuum retraction load. 
       FIGS. 23 and 24  illustrate that loads other than vacuum loads may be utilized to assist in retracting a needle member with various safety configurations described herein. Indeed, in simplified configurations, which may be desirable from cost and other perspectives, needle re-insertion prevention may be accomplished using needle assemblies such as those described herein, with only manual retraction of the needle member (i.e., while various self-retracting-after-full-insertion configurations are described herein, manual retraction configurations also may benefit from the safety provided by the needle assemblies described herein wherein re-insertion of a needle after a first full insertion is physically prevented). 
     Referring back to  FIGS. 11, 13, 15, 19, and 21 , the syringe body (preloaded with medicine), needle assembly, and plunger control assembly are illustrated ( 202 ) as being part of an in-situ process (i.e., adjacent the point of use—such as in a hospital or home healthcare scenario, and after preoperative diagnostics and patient preparation  200 ). In other embodiments, a plunger control assembly such as that illustrated in  FIGS. 6 and 7B  ( 44 ) may arrive at the intervention site pre-assembled with a syringe body (i.e., such an assembly would be pre-assembled before delivery to the intervention site); further, in other embodiments, a needle assembly such as that illustrated in  FIGS. 6 and 7A  ( 32 ) may arrive at the intervention site pre-assembled with a syringe body (i.e., such an assembly would be pre-assembled before delivery to the intervention site); indeed, in other embodiments, both a needle assembly ( 32 ) and plunger control assembly ( 44 ) may be pre-assembled with a syringe body at the preparation factory or other location before delivery to the intervention site. 
     Suitable polymeric materials for the various components of these embodiments include but are not limited to acetal, polycarbonate, poly vinyl chloride, polypropylene, polystyrene, ABS, nylon, glass-filled nylon, glass-filled acetal, peek, glass-filled peek, carbon-fiber-filled peek, COC (cyclic olefin copolymer), COP (cyclic olefin polymer), PEI (Ultem), glass-filled PEI, and pekk, as well as copolymers thereof. 
     Suitable structural metals for structures such as the plunger insertion member include but are not limited to stainless steel, steel with chrome coating, brass, nickel, and titanium, as well as alloys thereof. 
     Suitable needle member sizes range from about 34 gauge/6 millimeters long-to about 20 gauge/2.5 inches long. 
     Various exemplary embodiments of the invention are described herein. Reference is made to these examples in a non-limiting sense. They are provided to illustrate more broadly applicable aspects of the invention. Various changes may be made to the invention described and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s) to the objective(s), spirit or scope of the present invention. Further, as will be appreciated by those with skill in the art that each of the individual variations described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present inventions. All such modifications are intended to be within the scope of claims associated with this disclosure. 
     Any of the devices described for carrying out the subject diagnostic or interventional procedures may be provided in packaged combination for use in executing such interventions. These supply “kits” may further include instructions for use and be packaged in sterile trays or containers as commonly employed for such purposes. 
     The invention includes methods that may be performed using the subject devices. The methods may comprise the act of providing such a suitable device. Such provision may be performed by the end user. In other words, the “providing” act merely requires the end user obtain, access, approach, position, set-up, activate, power-up or otherwise act to provide the requisite device in the subject method. Methods recited herein may be carried out in any order of the recited events which is logically possible, as well as in the recited order of events. 
     Exemplary aspects of the invention, together with details regarding material selection and manufacture have been set forth above. As for other details of the present invention, these may be appreciated in connection with the above-referenced patents and publications as well as generally known or appreciated by those with skill in the art. For example, one with skill in the art will appreciate that one or more lubricious coatings (e.g., hydrophilic polymers such as polyvinylpyrrolidone-based compositions, fluoropolymers such as tetrafluoroethylene, hydrophilic gel or silicones) may be used in connection with various portions of the devices, such as relatively large interfacial surfaces of movably coupled parts, if desired, for example, to facilitate low friction manipulation or advancement of such objects relative to other portions of the instrumentation or nearby tissue structures. The same may hold true with respect to method-based aspects of the invention in terms of additional acts as commonly or logically employed. 
     In addition, though the invention has been described in reference to several examples optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention. In addition, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. 
     Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in claims associated hereto, the singular forms “a,” “an,” “said,” and “the” include plural referents unless the specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as claims associated with this disclosure. It is further noted that such claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. 
     Without the use of such exclusive terminology, the term “comprising” in claims associated with this disclosure shall allow for the inclusion of any additional element—irrespective of whether a given number of elements are enumerated in such claims, or the addition of a feature could be regarded as transforming the nature of an element set forth in such claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity. 
     The breadth of the present invention is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of claim language associated with this disclosure.