Patent Publication Number: US-2020297942-A1

Title: System and method for adjustable length needle

Description:
The present application claims priority to (1) U.S. Provisional Patent Application Ser. No. 62/820,599, filed on Mar. 19, 2019, under attorney docket number CM.30024.00, and entitled “SYSTEM AND METHOD FOR ADJUSTABLE LENGTH NEEDLE.” This application includes subject matter similar to the subject matter described in the following co-owned U.S. patent applications: (2) U.S. Utility patent application Ser. No. 14/696,342, filed Apr. 24, 2015 under attorney docket number CM.20003.00 and entitled “SYSTEM AND METHOD FOR SAFETY SYRINGE”; (3) U.S. Utility patent application Ser. No. 14/543,787, filed Nov. 17, 2014 under attorney docket number CM.20002.00 and entitled “SYSTEM AND METHOD FOR DRUG DELIVERY WITH A SAFETY SYRINGE”; and (4) U.S. Utility patent application Ser. No. 14/321,706, filed Jul. 1, 2014 under attorney docket number CM.20001.00 and entitled “SAFETY SYRINGE.” The contents of the above-mentioned applications are fully incorporated herein by reference as though set forth in full. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to injection systems, devices, and processes for facilitating various levels of control over injection target access, and more particularly to injection systems and methods related to injection in healthcare environments. Even more particularly, the present invention relates to injection systems, devices, and processes for adjusting a length of a needle in an injection system. 
     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 manifold assembly of  FIG. 2B  may be used to administer liquid drugs to the patient intravenously with or without the use of an intravenous infusion bag. 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 ( 14 ) which are configured to engage a flange on the female fitting ( 18 ) 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 ,  26 ) 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. Other “safety syringes” are described in U.S. patent application Ser. Nos. 14/696,342, 14/543,787, 14/321,706, 62/416,102, 62/431,382, and 62/480,276, the contents of which have been incorporated herein by reference. 
     Further complicating the syringe marketplace is an increasing demand for pre-filled syringe assemblies such as those depicted in  FIGS. 5A and 5B , 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 ( FIG. 5A  shows the cap  35  in place;  FIG. 5B  has the cap removed to illustrate the Luer interface ( 14 ). Liquid medicine may reside in the volume, or medicine reservoir, ( 40 ) between the distal seal ( 35 ) and the distal end ( 37 ) of the plunger tip ( 36 ). The plunger tip ( 36 ) may comprise a standard butyl rubber material and may be coated, such as with a biocompatible lubricious coating (e.g., polytetrafluoroethylene (“PTFE”)), to facilitate preferred sealing and relative motion characteristics against the associated syringe body ( 34 ) structure and material. The proximal end of the syringe body ( 34 ) in  FIG. 5B  comprises a conventional integral syringe flange ( 38 ), which is formed integral to the material of the syringe body ( 34 ). The flange ( 38 ) is configured to extend radially from the syringe body ( 34 ) and may be configured to be a full circumference, or a partial circumference around the syringe body ( 34 ). A partial flange is known as a “clipped flange” while the other is known as a “full flange.” The flange is used to grasp the syringe with the fingers to provide support for pushing on the plunger to give the injection. The syringe body ( 34 ) preferably comprises a translucent material such as a glass or polymer. To form a contained volume within the medicine chamber or 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. 
     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 the system ( 41 ) featured in  FIG. 5C , which attempts to meet all of the standards, or at least a portion thereof, with one solution by including most or all parts needed to perform an injection (body, stopper, needle, plunger, etc.) 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. 
     Regardless of the type of injection system, the ability to adjust/select the length of a needle in a preassembled injection system can provide many advantages. Various medications are ideally injected into different patient tissue targets and tissue depths. For instance, the influenza vaccine is typically administered intramuscularly, i.e., deeper (e.g., about 1 inch) into the muscular tissue (e.g., deltoid muscle) of a patient. On the other hand, insulin is typically administered subcutaneously, i.e., less deep (e.g., about 0.5 inch) between the dermis/epidermis and muscular tissue (e.g., the abdomen) of a patient. While the influenza vaccine and insulin are typically administered in these targets and target depths, these medicines may be administered in different targets and target depths on the patient&#39;s body depending on the clinical situation, patient, and/or user. Existing injection systems require selection and attachment of different needles to injection system bodies in order to vary the length of the needle in an injection system to conform to the medication to be delivered. Selection and attachment of needles to injection system bodies introduces opportunities for user error and increases the time for injections, the risk of unintentional needle sticks, and corresponding patient anxiety. Alternatively, preassembled injection systems can be divided into species with different needle lengths. Having different species of preassembled injection systems also introduces opportunities for user error and complexity to medical equipment supply chains. The ability to adjust/select the length of the needle and a preassembled injection system reduces user error and patient anxiety, and streamlines medical equipment supply chains. 
     There is a need for injection systems that address the shortcomings of currently-available configurations. In particular, there is a need for preassembled injection systems with adjustable length needles. Further, there is a need for preassembled injection systems in which a needle length can be adjusted/selected either during or after removal of rigid needle shield while minimizing opportunities for user error. 
     SUMMARY 
     Embodiments are directed to injection systems. In particular, the embodiments are directed to preassembled injection systems with adjustable/selectable needle lengths. 
     In one embodiment, an injection system includes a body member having a body connection member at a distal end thereof. The system also includes a needle hub assembly coupled to the distal end of the injection system body. The needle hub assembly includes a needle hub coupled to the body connection member, a needle coupled to the needle hub, and a spacer removably coupled to the needle hub. The spacer reduces an exposed length of the needle. 
     In one or more embodiments, removing the spacer from the needle hub increases the exposed length of the needle. The body connection member may include an annular recess, and the needle hub may include a ring configured to retain the needle hub on the body connection member. The body connection member may include an annular ledge adjacent the annular recess, and the ring may be configured to move past the annular ledge in a proximal direction. The needle hub may include a space configured to house the ring to prevent movement of the ring along a longitudinal axis relative to the needle hub. 
     In one or more embodiments, the needle hub includes a detent, and the spacer includes a slot configured to interact with the detent to temporarily prevent movement of the spacer along a longitudinal axis relative to the needle hub, thereby removably coupling the spacer to the needle hub. The detent and the slot may be configured such rotating the spacer relative to the needle hub uncouples the space from the needle hub. 
     In one or more embodiments, the system also includes a rigid needle shield removably coupled to the spacer. The needle hub, the spacer, and the rigid needle shield may be configured such that pulling the rigid needle shield relative to the body member releases the rigid needle shield from the spacer and rotating the spacer relative to the body member releases the spacer from the needle hub. The spacer may include an annular recess, and the rigid needle shield may include an annular protrusion configured to interfere with the annular recess to temporarily prevent removal of the rigid needle shield along a longitudinal axis relative from the spacer. 
     In one or more embodiments, an inner surface of the spacer forms a seal against an outer surface of the needle hub. The system may also include a gasket disposed between the distal end of the body member and an inner surface of the needle hub. The gasket may be configured to prevent contamination of an interior of the body member. 
     In another embodiment, an injection system includes a body member having a body connection member at a distal end thereof. The system also includes a needle hub assembly coupled to the distal end of the injection system body. The needle hub assembly includes a needle hub coupled to the body connection member, a needle coupled to the needle hub, and a spacer movably coupled to the needle hub. Moving the spacer along a longitudinal axis modifies an exposed length of the needle. 
     In one or more embodiments, the system also includes an actuator configured to move the spacer along the longitudinal axis. The actuator may include a plurality of ratchet teeth on the needle hub defining a plurality of spaces, and a pawl coupled to the spacer. The pawl may be configured to movably lodge in each of the plurality of spaces. Moving the pawl along the longitudinal axis may move the spacer along the longitudinal axis. 
     In one or more embodiments, the system also includes a gasket disposed between the distal end of the body member and an inner surface of the needle hub. The gasket may be configured to prevent contamination of an interior of the body member. The system may also include an O-ring disposed between a distal end of the needle hub and an inner surface of the spacer. The O-ring may be configured to prevent contamination of an interior of the spacer. 
     In still another embodiment, an injection system includes a body member having a body connection member at a distal end thereof. The system also includes a needle hub assembly coupled to the distal end of the injection system body. The needle hub assembly includes a needle hub coupled to the body connection member, a needle coupled to the needle hub, and a spacer movably coupled to the needle hub. Rotating the spacer about a longitudinal axis modifies an exposed length of the needle. 
     In one or more embodiments, the needle hub includes a grooved portion, and the spacer includes a radially inwardly extending member configured to interfere with the grooved portion of the needle hub to control movement of the space along the longitudinal axis. The grooved portion may define a helical groove. The grooved portion may include a first flattened end, and the radially inwardly extending member may be aligned with the helical groove and not aligned with the first flattened end. 
     In one or more embodiments, the first flattened end includes a radially outwardly extending detent configured to retain the radially inwardly extending member in the first flattened end. The radially inwardly extending member may include a radially inwardly extending bump configured to interfere with the radially outwardly extending detent to retain the radially inwardly extending member in the first flattened end. The grooved portion may include a second flattened end opposite of the first flattened end. The radially inwardly extending member may not be aligned with the second flattened end. The second flattened end may include a radially outwardly extending detent configured to retain the radially inwardly extending member in the second flattened end. 
     In one or more embodiments, the grooved portion defines two helical grooves, and the spacer includes two radially inwardly extending members, including the radially inwardly extending member. The system may include an O-ring disposed between an inner surface of the spacer and an outer surface of the needle hub to form a seal therebetween. The system may include a gasket disposed between an outer surface of the needle and an inner surface of the needle hub to form a seal therebetween. 
     The aforementioned and other embodiments of the invention are described in the Detailed Description which follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described below are for illustration purposes only. The drawings are not intended to limit the scope of the present disclosure. 
       The foregoing and other aspects of embodiments are described in further detail with reference to the accompanying drawings, in which the same elements in different figures are referred to by common reference numerals, wherein: 
         FIGS. 1A to 5C  illustrate various aspects of conventional injection syringe configurations. 
         FIGS. 6 to 8B and 10  illustrate various aspects of an adjustable/selectable injection system according to some embodiments. 
         FIG. 9  depicts a retaining ring for use with adjustable/selectable injection systems according to some embodiments. 
         FIGS. 11 to 15  illustrate various aspects of an adjustable/selectable injection system according to some embodiments. 
         FIGS. 16 to 23  illustrate various aspects of an adjustable/selectable injection system according to some embodiments. 
         FIGS. 24 and 25  illustrate various aspects of a method of manufacturing an injection system according to some embodiments. 
     
    
    
     In order to better appreciate how to obtain the above-recited and other advantages and objects of various embodiments, a more detailed description of embodiments is provided with reference to the accompanying drawings. It should be noted that the drawings are not drawn to scale and that elements of similar structures or functions are represented by like reference numerals throughout. It will be understood that these drawings depict only certain illustrated embodiments and are not therefore to be considered limiting of scope of embodiments. 
     DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS 
     Removable Needle Length Spacer 
       FIG. 6  depicts the distal end of a preassembled injection system  600  including a single needle  610  with multiple exposed length configurations according to some embodiments. The injection system  600  includes an injection system body  612 , which may be, for example, a syringe body or a cartridge. The injection system  600  may be a traditional injection system or a safe injection system that retracts the needle at least partially inside the needle hub  614  and/or injection system body  612  after injection to reduce the risk of unintentional needle sticks. Examples of safe injection systems are described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. 
     The proximal end of the preassembled injection system  600 , which may include components such as stopper members and a plunger rod, is not depicted or described in this specification because the components of the adjustable/selectable exposed needle length injection systems described herein are located at the distal end of the injection systems. The components of the adjustable/selectable exposed needle length injection systems described herein are usable/compatible with off the shelf injection system components such as injection system bodies, stopper members, and plunger rods. The components of the adjustable/selectable exposed needle length injection systems described herein are also usable/compatible with components configured to be compatible with off the shelf injection system components, such as those described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. 
     Still referring to  FIG. 6 , the injection system  600  also includes a needle length spacer  616  which is passed over the distal end of the needle  610  and removably coupled to the needle hub  614 . The needle  610  is coupled (removably in some embodiments) to the needle hub  614  through which the needle  610  extends. The injection system  600  also includes a rigid needle shield  618  removably coupled to the needle length spacer  616 . Further details regarding the coupling of various components to each other are described below. 
       FIG. 7  depicts the preassembled injection system  600  with the rigid needle shield  618  removed. This places the injection system  600  in a short needle/subcutaneous configuration. The exposed length  620  of the needle  610  in the short configuration, which extends distally beyond the distal end of the needle length spacer  616 , may be configured to be suitable for subcutaneous injection (e.g., approximately 0.5 inches). Removing the rigid needle shield  618  also exposes the sharp distal end of the needle  610 . 
       FIGS. 8A to 8C  depict removal of the needle length spacer  616  from the injection system  600  after removal of the rigid needle shield  618  to convert the injection system  600  from a short needle/subcutaneous configuration to a long needle/intramuscular configuration.  FIG. 8A  depicts the injection system  600  in a short needle/subcutaneous configuration similar to the one depicted in  FIG. 7 .  FIG. 8A  depicts the needle length spacer  616  in shadow to depict the detent  622  on the needle hub  614  configured to temporarily prevent movement of the needle length spacer  616  along the longitudinal axis of the injection system  600  when the injection system  600  is in the short needle/subcutaneous configuration. 
       FIG. 8B  depicts the needle length spacer  616  being removed from the needle hub  614 . The needle length spacer  616  includes a longitudinal slot  624  hidden behind the rectangular protrusion on the removable spacer  616  that allows the needle length spacer  616  to be slid free from the detent  622  on the needle hub  614  when the slot  624  is rotationally aligned with the detent  622 . 
     Accordingly, to convert the injection system  600  from a short needle/subcutaneous configuration ( FIG. 8A ) have to a long needle/intramuscular configuration ( FIG. 8C ), the needle length spacer  616  is rotated to align the slot  624  with the detent  622  and then pulled distally along the longitudinal axis of the injection system  600  to remove the needle length spacer  616  from the needle hub  614  and the injection system  600 . 
       FIG. 8C  depicts the injection system  600  in a long needle/intramuscular configuration. The injection system  600  is placed in the long needle configuration after complete removal of the needle length spacer  616  from the needle hub  614  and the needle  610 . The exposed length  620 ′ of the needle  610  in the long configuration, which extends distally beyond the distal end of the needle hub  614 , may be configured to be suitable for intramuscular injection (e.g., approximately 1 inch). 
       FIG. 9  depicts a metal retaining ring  626  for the use with a needle hub  614  of the preassembled injection system  600  depicted and described herein according to some embodiments. Because the metal retaining ring  626  includes teeth  627  that are biased in such a way to bend more readily in one direction compared to the opposite direction, the retaining ring  626  can slip proximally over an annular ledge  628  more easily at the distal end of the system body  612 , while providing relatively more substantial resistance to removing the retaining ring  626  distally over the annular ledge  628 , as shown in  FIG. 10 . There is a self-braking action that occurs between the teeth  627  and the system body  612  that helps resist the removal of the retaining ring  626  over the annular ledge  628 . The teeth  627  tend to bind harder to the annular ledge  628  as more removal force is applied. This is due to the non-shallow angle that is formed between the teeth  627  and the annular ledge  628  after assembly, which increases friction between the teeth  627  and the annular ledge  628  with increasing removal force, thereby preventing the teeth  627  from skipping over the annular ledge  628 . The domed curvature of the teeth  627  and the surrounding metal of the retaining ring  626  lends structural strength to the teeth  627 , which thereby squeeze the annular ledge  628  with substantial radial force, and helps to reinforce the self-braking action and help the teeth  627  to resist skipping over the annular ledge  628 . Because the needle hub  614  defines a space  630  in which the retaining ring  626  is disposed and because the system body  612  defines an annular recess configured to receive the retaining ring  626 , interference between the annular ledge  628  and the retaining ring  626  allows the needle hub  614  to be mounted onto the system body  612  in the proximal direction while preventing removal of the needle hub  614  from the system body  612 . The metal retaining ring  626  has greater hardness and elasticity compared to the system body  612  due to its metallic composition. 
       FIG. 10  depicts a preassembled injection system  600  according to some embodiments. The injection system  600  includes a needle  610 , a system body  612 , a needle hub  614 , a needle length spacer  616 , and a rigid needle shield  618 . The needle hub  614  is coupled to the system body  612  via a radial interference fit between the retaining ring  626  in the needle hub  614  and an annular ledge  628  on the system body  612 . The needle length spacer  616  is removably coupled to the needle hub  614  via an interference fit between the detent  622  on the needle hub  614  and the portion of the needle length spacer  616  defining the slot  624  (see  FIG. 8B ). The needle  610  is removably coupled to the needle hub  614  via a pair of needle latches  631  as described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. 
     The needle  610 , the needle hub  614 , and the needle length spacer  616  formed a needle hub assembly. The rigid needle shield  618  is removably coupled to the needle length spacer  616  via an interference fit between an annular recess  632  on the needle length spacer  616  and an annular protrusion  634  on an inner surface of the rigid needle shield  618 . The rigid needle shield  618  can be removed from the needle length spacer  616  by pulling the rigid needle shield  618  and the needle length spacer  616  apart from each other along the longitudinal axis of the injection system  610  with sufficient force to overcome the interference fit between the annular recess  632  and the annular protrusion  634 . As described above, the detent  622  on the needle hub  614  prevents the needle length spacer  616  from pulling apart from the needle hub  614  until the needle length spacer  660  is rotated relative to the needle hub  614  two aligned the detent  622  with the slot  624  on the needle length spacer  616 . Accordingly, the rigid needle shield  618  can be removed from the rest of the injection system  600  by pulling the rigid needle shield  618  in a distal direction. Further, the needle length spacer  616  can be removed from the rest of the injection system  600  (with or without the rigid needle shield  618 ) by rotating the needle length spacer  616  to align the detent  622  with the slot  624  and pulling the needle length spacer  616  in a distal direction. While  FIGS. 8A to 8C  show removal of the needle length spacer  616  from the rest of the injection system  600  after the rigid needle shield  618  has been removed, the needle length spacer  616  can be removed from the rest of the injection system  600  along with the rigid needle shield  618 , which would remain attached to the needle length spacer  616 . This allows a user to selectively remove various components of the injection system  600  to place the system  600  in either the short needle (remove only the rigid needle shield  618  by pulling) or the long needle (remove the needle length spacer  616  along with the rigid needle shield  618  by twisting and pulling) while minimizing the occurrence of an unintentional needle sticks. On the other hand, if a user places the injection system  600  in either the short needle or the long needle configuration by mistake, the user can place the injection system  600  in the other configuration by either removing and/or replacing the needle length spacer  616 . 
     The injection system  600  also includes a gasket  636  disposed between the distal end of the system body  612  and an inner surface of the needle hub  614 . The gasket is configured to prevent contamination of the interior of the system body  612  and the injectable contained therein. 
     By allowing a user to select between short and long needle configurations, the preassembled injection system  600  described above facilitates use of a single preassembled injection system for both subcutaneous (short needle configuration) and intramuscular (long needle configuration) injections. The preassembled injection system  600  allows removal of either the rigid needle shield  618  (short needle configuration) or the needle length adapter  616  along with the rigid needle shield  618  (long needle configuration) from the shipping configuration with the rigid needle shield  618  attached. Selection of a short or long needle configuration from the shipping configuration minimizes the risk of inadvertent needle sticks compared to systems that involve manipulation of components near the tip of the needle  610 . Further, the preassembled injection system  600  allows a user to transition between short and long needle configurations after removal of the rigid needle shield  618  in case the wrong configuration is selected when removing the rigid needle shield  618 . 
     While the preassembled injection system  600  described above may be selectable between a 0.5 inches short configuration and a 1 inch long configuration, other embodiments include components of different sizes that can result in two configurations with different lengths. While the preassembled injection system  600  described above includes a luer taper connector, other types of connectors may be used to couple the needle hub to the injection system body. While the preassembled injection system  600  described above includes the needle latches  631  of a safe injection system, other embodiments may include a standard needle hub assemblies without needle retraction features. 
     Movable Needle Length Spacer 
       FIG. 11  depicts a preassembled injection system  1100  including a single needle  1110  with multiple exposed length configurations according to some embodiments. The injection system  1100  includes an injection system body  1112 , which may be, for example, a syringe body or a cartridge. The injection system  1100  may be a traditional injection system or a safe injection system that retracts the needle at least partially inside the needle hub  1114  and/or injection system body  1112  after injection to reduce the risk of unintentional needle sticks. Examples of safe injection systems are described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. 
     Other components of the injection system  1100 , such as stopper members and a plunger rod, are not depicted or described in this specification because the components of the adjustable/selectable exposed needle length injection systems described herein are located at the distal end of the injection systems. The components of the adjustable/selectable exposed needle length injection systems described herein are usable/compatible with off the shelf injection system components such as injection system bodies, stopper members, and plunger rods. The components of the adjustable/selectable exposed needle length injection systems described herein are also usable/compatible with components configured to be compatible with off the shelf injection system components, such as those described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. 
     Still referring to  FIG. 11 , the injection system  1100  also includes a movable needle length spacer  1116  which is movably coupled to the needle hub  1114 . The needle  1110  is coupled (removably in some embodiments) to the needle hub  1114  through which the needle  1110  extends. The injection system  1100  also includes a rigid needle shield  1118  removably coupled to the needle length spacer  1116 . Moreover, the injection system  1100  includes an actuator  1122  configured to move the needle length spacer  1116  along the longitudinal axis of the injection system  1100  thereby modifying/adjusting an exposed length  1120  of the needle  1110  (see  FIGS. 12 to 14B ). Further details regarding the coupling of various components to each other are described below. 
       FIG. 12  depicts the injection system  1100  with the rigid needle shield  1118  removed (see  FIG. 11 ). Removing the rigid needle shield  1118  exposes the sharp distal end of the needle  1110 . The injection system depicted in  FIG. 12  is in a short needle/subcutaneous configuration. The exposed length  1120  of the needle  1110  in the short configuration, which extends distally beyond the distal end of the needle length spacer  1116 , may be configured to be suitable for subcutaneous injection (e.g., approximately 0.5 inches). 
       FIGS. 13A and 13B  depict the injection system  1100  in a short needle/subcutaneous configuration.  FIG. 13A  depicts the actuator  1122  in detail. The actuator  1122  includes a plurality of ratchet teeth  1121  on the needle hub  1114  that define a plurality of spaces  1123 . The actuator  1122  also includes a pawl  1124  coupled to the needle length spacer  1116 . The pawl  1124  includes two extensions  1125  on its proximal end that are spaced to fit inside adjacent spaces  1123  on the needle hub  1114 . In  FIGS. 13A and 13B , the pawl  1124  is disposed in its distal most position relative to the needle hub  1114 , thereby placing the actuator  1122  and the needle length spacer  1116  in their respective distal most positions. This in turn places the injection system  1100  in its short needle/subcutaneous configuration in which the exposed length  1120  of the needle  1110  is reduced by the overlapping needle length spacer  1116 . Interference between the extensions  1125  and the ratchet teeth  1121  prevent relative movement of the needle length spacer  1116  and the needle hub  1114  along the longitudinal axis of the injection system  1100 . 
       FIGS. 13A and 13B  also depict a retaining ring  626 , similar to the one described above for use in the preassembled injection system  600 , for the use with the needle hub  1114  of the preassembled injection system  1100 . Because the retaining ring  626  includes teeth  267  that bend more readily in one direction compared to the opposite direction, the retaining ring  626  can slip proximally over an annular ledge  628  at the distal end of the system body  1112 , while providing substantial resistance to removing the retaining ring  626  distally over the annular ledge  628 . Because the needle hub  1114  defines a space  1130  in which the retaining ring  626  is disposed and because the system body  1112  defines an annular recess configured to receive the retaining ring  626 , interference between the annular ledge  628  and the retaining ring  626  allows the needle hub  1114  to be mounted onto the system body  1112  in the proximal direction while preventing removal of the needle hub  1114  from the system body  1112 . 
     The injection system  1100  also includes a gasket  636  disposed between the distal end of the system body  1112  and an inner surface of the needle hub  1114 . The gasket is configured to prevent contamination of the interior of the system body  1112  and the injectable contained therein. The injection system  1100  further includes an O-ring  1138  disposed between a distal end of the needle hub  1114  and an inner surface of the needle length spacer  1116 . The O-ring  1138 , in conjunction with the rigid needle shield  1118 , are configured to prevent contamination of respective interiors of the needle length spacer  1116  and the needle hub  1114 . 
       FIGS. 14A and 14B  depict the injection system  1100  in a long needle/intramuscular configuration. In the long needle configuration, the two extensions  1125  on the proximal end of pawl  1124  have been moved to their proximal most position relative to the needle hub  1114 , thereby placing the actuator  1120  and the needle length spacer  1116  in their respective proximal most positions. This in turn places the injection system  1100  in its long needle/intramuscular configuration in which the exposed length  1120 ′ of the needle  1110  is increased because the needle length spacer  1116  overlaps with less of the needle  1110 . The pawl  1124  can be depressed by pushing down on the extensions  1125  to remove the interference and allow the pawl  1124  to move proximally (or distally) relative to the needle hub  1114  along the longitudinal axis of the injection system  1100 . This allows the needle length spacer  1116  to move relative to the needle hub  1114  along the longitudinal axis of the injection system  1100  as shown in arrow  1140 . 
       FIG. 15  depicts a preassembled injection system  1100  according to some embodiments. The injection system  1100  includes a needle  1110 , a system body  1112 , a needle hub  1114 , a needle length spacer  1116 , and a rigid needle shield  1118 . The needle hub  1114  is coupled to the system body  1112  via an interference fit between the retaining ring  626  in the needle hub  1114  and an annular ledge  628  on the system body  1112 . The injection system  1100  also includes a movable needle length spacer  1116  which is movably coupled to the needle hub  1114  via an interference fit between extensions  1125  on a pawl  1124  coupled to the needle length spacer  1116  and ratchet teeth  1121  on the needle hub  1114 . The needle  1110  is removably coupled to the needle hub  1114  via a pair of needle latches  631  as described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. The injection system  1100  also includes a rigid needle shield  1118  removably coupled to the needle length spacer  1116 . Moreover, the injection system  1100  includes an actuator  1122  configured to move the needle length spacer  1116  along the longitudinal axis of the injection system  1100  thereby modifying/adjusting an exposed length  1120  of the needle  1110 . 
     The injection system  1100  also includes a gasket  636  disposed between the distal end of the system body  1112  and an inner surface of the needle hub  1114 . The gasket is configured to prevent contamination of the interior of the system body  1112  and the injectable contained therein. The injection system  1100  further includes an O-ring  1138  disposed between a distal end of the needle hub  1114  and an inner surface of the needle length spacer  1116 . The O-ring  1138 , in conjunction with the rigid needle shield  1118  (which seals the distal end of the movable needle length spacer  1116  and the needle  1110  tip), are configured to prevent contamination of respective interiors of the needle length spacer  1116  and the needle hub  1114 . 
     By allowing a user to select between short and long needle configurations either before or after removal of the rigid needle shield  1118 , the preassembled injection system  1100  described above facilitates use of a single preassembled injection system for both subcutaneous (short needle configuration) and intramuscular (long needle configuration) injections. The preassembled injection system  1100  allows modification of the amount of overlap between the needle length spacer  1116  and the needle  1110  by manual manipulation of an actuator  1122 . Selection of a short or long needle configuration from the shipping configuration minimizes the risk of inadvertent needle sticks. Further, the preassembled injection system  1100  allows a user to transition between short and long needle configurations after removal of the rigid needle shield  1118  without exposing fingers to the sharp distal end of the needle  1110  in case the wrong configuration is selected when removing the rigid needle shield  1118 . Moreover, the preassembled injection system  1100  minimizes the risk of inadvertent bending the needle  1110  during needle length adjustment, as with the systems that involve manipulation of components near the tip of the needle  1110 . 
     While the preassembled injection system  1100  described above may be selectable between a 0.5 inches short configuration and a 1 inch long configuration, other embodiments include components of different sizes that can result in two configurations with different lengths. While the preassembled injection system  1100  described above includes a luer taper connector, other types of connectors may be used to couple the needle hub to the injection system body. While the preassembled injection system  1100  described above includes the needle latches  631  of a safe injection system, other embodiments may include a standard needle hub assemblies without needle retraction features. While the injection system  1100  is shown in two configurations in  FIGS. 13A to 14B , injection systems according to other embodiments may have more than two configurations allowing more than two exposed needle lengths to be manually controlled by the user. 
     Rotatable Needle Length Spacer 
       FIGS. 16 to 18  depict a preassembled injection system  1600  including a single needle  1610  with multiple exposed length configurations according to some embodiments. The injection system  1600  includes an injection system body  1612 , which may be, for example, a syringe body or a cartridge. The injection system  1600  may be a traditional injection system or a safe injection system that retracts the needle at least partially inside the needle hub  1614  and/or injection system body  1612  after injection to reduce the risk of unintentional needle sticks. Examples of safe injection systems are described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. 
     Other components of the injection system  1600 , such as stopper members and a plunger rod, are not depicted or described in this specification because the components of the adjustable/selectable exposed needle length injection systems described herein are located at the distal end of the injection systems. The components of the adjustable/selectable exposed needle length injection systems described herein are usable/compatible with off the shelf injection system components such as injection system bodies, stopper members, and plunger rods. The components of the adjustable/selectable exposed needle length injection systems described herein are also usable/compatible with components configured to be compatible with off the shelf injection system components, such as those described in U.S. Utility patent application Ser. No. 14/696,342, which has been previously incorporated by reference herein. 
     Still referring to  FIGS. 16 to 18 , the injection system  1600  also includes a movable needle length spacer  1616  which is movably coupled to the needle hub  1614 . The needle  1610  is coupled (removably in some embodiments) to the needle hub  1614  through which the needle  1610  extends. The injection system  1600  also includes a rigid needle shield  1618  removably coupled to the needle length spacer  1616  ( FIG. 16 ). The needle hub  1614 , the needle length spacer  1616 , and features thereof are configured to move the needle length spacer  1616  along the longitudinal axis of the injection system  1600  with rotation of the needle length spacer  1616  relative to the needle hub  1614 , thereby modifying/adjusting an exposed length  1620  of the needle  1610  (compare  FIGS. 17 and 18 ). Further details regarding various components of the needle hub  1614  and the needle length spacer  1616  are described below. 
       FIG. 16  depicts the injection system  1600  with the rigid needle shield  1618  coupled to the needle length spacer  1616 .  FIG. 17  depicts the injection system  1600  with the rigid needle shield  1618  removed. Removing the rigid needle shield  1618  exposes the sharp distal end of the needle  1610 . The injection system  1600  depicted in  FIG. 17  is in a short needle/subcutaneous configuration, in which the needle length spacer  1616  is at a distal most position on the needle hub  1614 , thereby covering a larger proximal portion of the needle  1610 . The exposed length  1620  of the needle  1610  in the short configuration, which extends distally beyond the distal end of the needle length spacer  1616 , may be configured to be suitable for subcutaneous injection (e.g., approximately 0.625 inches).  FIG. 18  depicts an injection system  1600  in a long needle/intramuscular configuration, in which the needle length spacer  1616  is at a proximal most position on the needle hub  1614 , thereby covering a smaller proximal portion of the needle  1610 . The exposed length  1620 ′ of the needle  1610  in the long configuration, which extends distally beyond the distal end of the needle length spacer  1616 , may be configured to be suitable for intramuscular injection (e.g., approximately 1 inch). 
       FIG. 19  depicts an injection system  1600  in the short needle/subcutaneous configuration with the rigid needle shield  1618  removed, similar to the injection system  1600  shown in  FIG. 17 . The needle hub  1614  includes a grooved portion  1622  on which the needle length spacer  1616  is coaxially disposed. The grooved portion  1622  of the needle hub  1614  defines a helical groove  1624 . 
       FIG. 20  is a detailed view depicting the distal end of the injection system  1600  in  FIG. 19  with a portion of the proximal end of the needle length spacer  1616  cut away to visualize a radially inwardly extending member/wing  1626 . The radially inwardly extending member/wing  1626  is part of and extends radially inward from an interior surface of the needle length spacer  1616 . The portion of the interior surface of the needle length spacer  1616  from which the radially inwardly extending member/wing  1626  extends has been cut away in  FIG. 20  to visualize the radially inwardly extending member/wing  1626 . 
     As shown in  FIG. 20 , the radially inwardly extending member/wing  1626  extending from the needle length spacer  1616  is disposed in the helical groove  1624  defined by the needle hub  1614 . The radially inwardly extending member/wing  1626  is aligned with the middle portion of the helical groove  1624  such that the radially inwardly extending member/wing  1626  can travel in the helical groove  1624  with rotation of the needle length spacer  1616  relative to the needle hub  1614  without significant resistance. 
     The helical groove  1624  includes flattened proximal and distal ends  1628 ,  1630 , which are circumferential instead of helical due to a change in the slopes of the flattened proximal and distal ends  1628 ,  1630  relative to the remaining middle portion of the helical groove  1624 . As such, the flattened proximal and distal ends  1628 ,  1630  are skewed relative to/out of alignment with the radially inwardly extending member/wing  1626 . The misalignment between the flattened proximal and distal ends  1628 ,  1630  and the radially inwardly extending member/wing  1626  increases frictional forces therebetween to wedge/retain the radially inwardly extending member/wing  1626  in the flattened proximal and distal ends  1628 ,  1630 . For instance,  FIG. 20  shows the radially inwardly extending member/wing  1626  retained in the flattened distal end  1630  of the helical groove  1624 , which places the injection system  1600  depicted in the short needle/subcutaneous configuration. 
     The flattened proximal and distal ends  1628 ,  1630  of the helical groove  1624  also each include a radially outwardly extending detent  1632 . The radially outwardly extending detent  1632  is configured to interfere with a radially inwardly extending bump  1634  ( FIG. 21 ) extending radially inward from the radially inwardly extending member/wing  1626  to further retain the radially inwardly extending member/wing  1626  in the flattened proximal and distal ends  1628 ,  1630 .  FIG. 21  is a detailed axial cross sectional view of the distal end of the injection system  1600  in  FIG. 20 . The interference between the radially outwardly extending detent  1632  and the radially inwardly extending bump  1634  increases the force required to remove the radially inwardly extending member/wing  1626  from the flattened proximal and distal ends  1628 ,  1630  to retain the radially inwardly extending member/wing  1626  in the flattened proximal and distal ends  1628 ,  1630 . While only the proximal end  1628  of the helical groove  1624  is shown with a radially outwardly extending detent  1632 , the distal end  1630  of the helical groove  1624  also includes a radially outwardly extending detent  1632 . 
       FIG. 22  shows the radially inwardly extending member/wing  1626  retained in the flattened proximal end  1628  of the helical groove  1624 , which places the injection system  1600  depicted in the long needle/intramuscular configuration. This configuration is similar to one shown in  FIG. 18  and described above. 
       FIG. 23  is a longitudinal cross sectional view of a distal end of an injection system  1600  according to some embodiments. The injection system  1600  is similar to the injection system  1600  depicted in  FIG. 16  where the injection system  1600  is in short needle/subcutaneous configuration with the rigid needle shield  1618  coupled thereto. The configuration depicted in  FIG. 23  is the transport configuration in which the preassembled injection system  1600  is shipped. In this configuration, the rigid needle shield  1618  seals the distal tip of the needle  1610  and the exposed length  1620  thereof against contamination from the environment. The injection system  1600  also includes an O-ring  1636  disposed between the needle hub  1614  and the needle length spacer  1616  to seal against (e.g., particulate) contamination from the environment. The injection system  1600  further includes a gasket  1638  disposed between the injection system body  1612  and the needle hub  1614  and around a proximal potion of the needle  1610  to seal against (e.g., particulate) contamination from the environment. 
     From the transport configuration depicted in  FIGS. 16 and 23 , a user can remove the rigid needle shield  1618  from the injection system  1600  to prepare the injection system  1600  for use as shown in  FIGS. 17 and 19 . In  FIGS. 17 and 19 , the injection system  1600  is in the short needle/subcutaneous configuration. In order to convert the injection system  1600  to the long needle/intramuscular configuration depicted in  FIGS. 18 and 22 , the user can rotate the needle length spacer  1616  relative to the needle hub  1614  in the direction indicated on the needle length spacer  1616  to move the needle length spacer  1616  from a distal position to a proximal position. The direction of rotation is dictated by the direction of the helical groove, which may be modified to modify the direction of rotation. In some embodiments, 1.5 rotations of the needle length spacer  1616  relative to the needle hub  1614  moves the needle length spacer  1616  from a distal position to a proximal position. 
     By allowing a user to select between short and long needle configurations, the preassembled injection system  1600  described above facilitates use of a single preassembled injection system for both subcutaneous (short needle configuration) and intramuscular (long needle configuration) injections. The preassembled injection system  1600  allows a user to transition between short and long needle configurations after removal of the rigid needle shield  1618  without exposing fingers to the sharp distal end of the needle  1610  in case the wrong configuration is selected when removing the rigid needle shield  1618 . Moreover, the preassembled injection system  1600  minimizes the risk of inadvertent bending the needle  1610  during needle length adjustment, as with the systems that involve manipulation of components near the tip of the needle  1610 . Coaxial placement of the needle length spacer  1616  around the needle  1610  also minimizes the risk of inadvertent bending the needle  1610 . 
       FIGS. 24 and 25  depict the manufacturing of injection systems  1600  like those depicted in  FIGS. 16 to 23  according to some embodiments. FIG.  24  depicts a threaded collar  1640 , which can be bonded to a distal portion  1642  to form the needle length spacer  1616 . The radially inwardly extending member/wing  1626  can be formed in the threaded collar  1640  before the threaded collar  1640  is bonded to the distal portion  1642 . These two components can be bonded ultrasonically or by laser welding. 
       FIG. 25  depicts positioning of the needle length spacer  1616  and the needle hub  1614  to allow the needle length spacer  1616  to be snapped over a distal end of the needle hub  1614 . The needle hub  1614  includes a longitudinal groove  1644  to facilitate the snapping the needle length spacer  1616  over the needle hub  1614  to position the radially inwardly extending member/wing  1626  into the helical groove  1624 . 
     While the injection systems  1600  depicted in  FIGS. 16 to 23  only illustrate one helical groove  1624 , injection systems according to some embodiments include a plurality of helical grooves with a corresponding plurality of radially inwardly extending members/wings. Injection systems including respective pluralities of helical grooves and radially inwardly extending members/wings may distribute loads/forces during use more evenly. While the injection systems  1600  depicted in  FIGS. 16 to 23  include only flattened proximal and distal ends  1628 ,  1630  and corresponding radially outwardly extending detents  1632 , injection systems according to some embodiments include one or more flattened sections and corresponding radially outwardly extending detents in the middle section of the helical groove to provide additional stopping points during longitudinal movement of the needle length spacer. These additional stopping points in turn provide corresponding additional needle length options for the injection systems. 
     While the preassembled injection system  1600  described above may be selectable between a 0.625 inches short configuration and a 1 inch long configuration, other embodiments include components of different sizes that can result in two configurations with different lengths. While the preassembled injection system  1600  described above includes a luer taper connector, other types of connectors may be used to couple the needle hub to the injection system body. While the preassembled injection system  1600  described above includes a standard needle hub assembly without needle retraction features, other embodiments may include needle latches of safe injection systems. 
     While the various systems and methods described herein depict injection systems having manually actuated plunger members, the needle length adjustment systems and methods described herein work equally well with automated or semi-automated injection systems such as injection pens. 
     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 injection information collection procedures may be provided in packaged combination for use in executing such interventions. These supply “kits” may further include instructions for use and/or may 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.