Abstract:
A dermal filler injector is provided which includes a handpiece and a coupling mechanism for operationally coupling the handpiece with a dermal filler cartridge. The handpiece includes a motor for controllably driving a plunger in the cartridge to provide effective and controlled injection of a dermal filler into skin.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/899,768, filed Nov. 4, 2013, the entire disclosure of which is incorporated herein by this reference. 
     
    
       [0002]    The present invention is generally directed to medical syringes and more specifically directed to syringe systems for controlled injection of dermal fillers. 
         [0003]    A number of medical and cosmetic applications involve injection of substances into the body. 
         [0004]    A conventional medical syringe is a simple piston pump consisting of a plunger that fits tightly in a cylindrical barrel. The plunger is manually pressed to inside cause liquid medicament or fluid to be expelled through a hypodermic needle fitted to a distal end of the barrel. Surprisingly, other than the materials used to make a syringe, conventional disposable syringes are much the same as the very earliest syringe designs. 
         [0005]    Aesthetic gels, for example, hydrogel-based dermal fillers are injectable, viscous gels which are used to plump up skin by adding volume to depressions or wrinkled regions of the skin, thereby decreasing the appearance of such wrinkles, depressions, or lack of volume and restoring a more youthful appearance. These compositions are introduced beneath the skin by injection using a syringe and a rather fine gauge needle. Classic syringe designs are far from optimal for the administration of these compositions, especially those that are highly viscous or cohesive. Such gels require relatively high extrusion forces to be expelled through a needle. Moreover, sometimes these gels are used in only trace amounts and must be introduced into skin with very high precision, for example, when used to fill in very minor depressions or fine wrinkles near sensitive structures of the face. This requires expert control over the injection procedure. 
         [0006]    Using a traditional syringe, physicians are required to supply possibly significant force, which may reduce the practitioner&#39;s ability to control the injection to the degree and with the precision needed for optimal results. Further, traditional syringes typically require the user&#39;s hand to be placed a significant distance from the site of the injection in order to operate the plunger, which may also lead to inaccuracy. Some more recently introduced dermal fillers are especially viscous and cohesive therefor amplifying the need a better device. 
         [0007]    The present invention provides a dermal filler injection system which overcomes at least some of the problems mentioned above. 
       SUMMARY 
       [0008]    Accordingly, a dermal filler injector device is provided for facilitating injection of a dermal filler into the skin. The device can be used with a standard syringe. For example, the device can be operationally coupled with a conventional, pre-filled dermal filler syringe to facilitate dermal filler treatment procedures. 
         [0009]    Generally, the device comprises a handpiece having a drive mechanism and a coupling mechanism. The handpiece comprises a housing shaped to be comfortably gripped and easily manipulated by a physician. For example, the handpiece may include opposing flanges for supporting a user&#39;s fingers during operation of the device such that the handpiece can be gripped in a manner similar to a manner in which a conventional syringe is typically gripped by a physician. 
         [0010]    The coupling mechanism is structured to removably engage the handpiece with a syringe, for example, a conventional, pre-filled dermal filler syringe. Such a dermal filler syringe generally includes a cartridge containing a dermal filler gel and a plunger slidable in the cartridge for ejecting the dermal filler through a needle disposed at a distal end of the cartridge. For example, the cartridge may contain about 0.5 mL to about 1.5 mL, for example, about 0.6 mL, about 0.8 mL, about 1.0 mL, about 1.2 mL, or about 1.4 mL of dermal filler product. 
         [0011]    In one embodiment, the drive mechanism is structured to be capable of moving the plunger in the cartridge to cause extrusion of dermal filler product in a controlled manner. In another embodiment, the drive mechanism is structured to be capable of moving the cartridge forward and backward relative to the handpiece, while the plunger remains fixed relative to the handpiece, to cause extrusion of the dermal filler product in a controlled manner. 
         [0012]    The handpiece may house a motor for driving the drive mechanism, and a battery for powering the motor. The drive mechanism may comprise any suitable mechanism for driving the movement of the syringe in the handpiece. For example, in one embodiment, the drive mechanism comprises a lead screw and a nut slidable along the lead screw. The nut may be engageable with a component of the syringe, and slidable along a fixed lead screw. In one embodiment, the nut is operationally engageable with the plunger of the syringe. In another embodiment, the nut is operationally engageable with the cartridge of the syringe, such that the cartridge is slidable along the lead screw. In another embodiment, the drive mechanism is structured such that when the coupling mechanism is operationally engaged with the syringe, the nut pulls the cartridge forward and backward while the plunger is held in a fixed position relative to the lead screw. 
         [0013]    Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent. 
         [0014]    Other aspects and features of the invention may be more clearly understood and appreciated with reference to the following Detailed Description and appended Drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIGS. 1A ,  1 B and  1 C show, respectively, a side view, a top view and a cross-sectional view of one embodiment of the invention. 
           [0016]      FIGS. 2A and 2B  show, respectively, a side view and a cross-sectional view of another embodiment of the invention. 
           [0017]      FIG. 3A-3C  each show a different housing that may be useful as a part of various handpieces of the invention. 
           [0018]      FIGS. 4A and 4B  show perspective views of a syringe coupling mechanism portion of an embodiment of the invention, which provides a means for rigidly connecting a ball screw of the handpiece with the plunger tip. 
           [0019]      FIGS. 5A-5C  show cross-sectional views of the coupling mechanism shown in  FIGS. 4A and 4B  during coupling of the components. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Turning now to  FIGS. 1A-1C , various views of a device in accordance with one embodiment of the invention are shown, generally at  10 . 
         [0021]    The device  10  generally comprises a handpiece  12  having a drive mechanism  14  and a coupling mechanism  18 . The handpiece  12  comprises a housing  20 . At least a portion of the housing  20  which may be shaped and sized to be comfortably gripped and easily manipulated by a physician. The handpiece  12  may include opposing flanges  22  for supporting a user&#39;s fingers during operation of the device  10  such that the handpiece  12  can be gripped in a manner similar to a manner in which a conventional syringe is typically gripped by a physician. 
         [0022]    The device  10  may be structured to be couplable to a standard pre-filled dermal filler syringe, or may include a dermal filler syringe  26  as a part of the device  10 . The syringe  26  generally includes a hub  28  which is connectable to a needle or cannula (not shown) at a distal end, a barrel/cartridge  32  for containing a dermal filler. Syringe  26  may further include a piston or plunger  34 , including a plunger tip  36 , movable within the cartridge  32 . The cartridge  32  may contain, for example, about 0.5 mL to about 1.5 mL, for example, about 0.6 mL, about 0.8 mL, about 1.0 mL, about 1.2 mL, or about 1.4 mL of dermal filler product, such as a crosslinked, hyaluronic acid based dermal filler product, such as, for example, Juvederm® XC, Juvederm® Voluma, Juvederm® Ultra, or Juvederm® Ultra Plus injectable dermal filler gels, manufactured by and available from Allergan, Inc., Irvine, Calif. 
         [0023]    In the embodiment shown in  FIGS. 1A-1C , the drive mechanism  14  is configured to move the cartridge  32  of the syringe while holding the plunger  34  or plunger tip  36  in a fixed position with respect to the handpiece  12 . 
         [0024]    For example, drive mechanism  14  includes a motor  38  for converting electrical power to mechanical power and a gear reduction for speed reduction and force multiplication. The drive mechanism  14  may further comprise a screw and nut assembly, for example, a ball screw assembly  40  comprising a ball screw  42  and ball nut  44  for converting rotational to linear motion, as well as force multiplication. Other components of the drive mechanism may include electrical components, for example, a battery  46 , switch(es), and/or wires, etc., for generating power and supplying power to the motor  38 . In some embodiments, drive mechanism  14  is structured to be capable of providing significant force, for example, 50 pounds, 100 pounds or more, of force to extrude a dermal filler from the cartridge through a needle having a gauge of 25 G, 27 G, 30 G, 31 G, 32 G or finer. 
         [0025]    In one embodiment, the motor  38  comprises a brushed DC motor. However, other motor technologies, including but not limited to, brushless DC motors, stepper motors, piezo-electric motors, etc. may alternatively or additionally be employed within the scope of the invention. These motors may be configured with a single or multistage planetary gearhead that reduced the output speed and increases the available torque. 
         [0026]    In one embodiment, the drive mechanism may be a “sliding drive” in which a lead screw is driven (rotated by motor) and a nut is held in a state of anti-rotation. The “sliding drive” functions by causing the nut to travel forward and back along the length of the screw as the screw rotates. The nut may be connected to a plunger which then drives a plunger tip forward in the syringe barrel, causing the dermal filler to be extruded. 
         [0027]    In the embodiment show in  FIGS. 1A-1D , the drive mechanism  14  is a sliding drive which is configured such that the ball nut  44  moves along the ball screw  42  and pulls the syringe cartridge  32  back and forth, while plunger tip  36  is help in a fixed position relative to the drive mechanism  14  and handpiece  12 . Advantageously, in this embodiment, device  10  allows for the overall length of the device  10  to decrease as dermal filler is extruded. This configuration advantageously provides a tactical sensation to the user that, as product is being extruded, the distance between the distal syringe tip and the proximal rear portion of the drive train becomes shorter. This shortening is analogous to the motion or feel a physician traditionally experiences when utilizing a normal, conventional barrel/piston manual syringe. 
         [0028]    The device  10  may comprise any further components necessary or desirable for enabling or facilitating operation by a user in accordance with the objectives described elsewhere herein. 
         [0029]    For example, in the shown embodiment, the device  10  further includes a counter rotation housing  54 , bearing  56 , gear  58  attached to ball screw  42 , switch  60  to enable user activation of the drive mechanism  14  for delivery of dermal filler and aspiration, motor output gear  62 , and thrust bearing  66 . 
         [0030]    Turning now to  FIGS. 2A and 2B , device  110  is provided in accordance with another embodiment of the invention. Device  110  includes handpiece  68  which is operationally couplable to a syringe, for example, a conventional dermal filler syringe. Device  110  is similar to device  10 , with some differences. For example, rather than the “sliding drive” described and shown with respect to device  10 , device  110  comprises a “side-by-side” drive mechanism  70 , and a coupling mechanism  71 . 
         [0031]    The coupling mechanism is structured to removably engage the handpiece with a syringe, for example, a conventional, pre-filled dermal filler syringe. Such a dermal filler syringe generally includes a cartridge containing a dermal filler gel and a plunger slidable in the cartridge for ejecting the dermal filler through a needle disposed at a distal end of the cartridge. The cartridge may contain about 0.5 mL to about 1.5 mL, for example, about 0.6 mL, about 0.8 mL, about 1.0 mL, about 1.2 mL, or about 1.4 mL of dermal filler product. 
         [0032]    In the shown embodiment, the drive mechanism  70  is generally configured such that a nut  72  is driven (e.g. rotated by motor  74  and powered by battery  75 ) and a lead screw  76  is prevented from rotating. 
         [0033]    This may be arranged in any suitable manner. For example, the “side by side” drive mechanism  70  functions by causing screw  76  to move forward relative to the rest of the drivetrain as ball nut  72  rotates about screw  76 , but remains fixed with respect to the handpiece. This motion moves a plunger tip  78  located in syringe  26  forward, causing product, e.g. dermal filler, loaded in the syringe cartridge  32  to be extruded. Suitable gears may be provided in order to affect the overall reduction of the system and to transfers power to an offset parallel axis. 
         [0034]    Like device  10 , device  110  may comprise any further components necessary or desirable for enabling or facilitating operation by a user in accordance with the objectives described elsewhere herein. For example, in the shown embodiment, the device  110  further includes a syringe holder/screw counter rotation housing  80 , ball nut  82 , gear  84  attached to ball nut  72 , bearing  86 , motor output gear  88 , bearing  90 , thrust bearing  92 , and switch  70  to enable user activation of the drive mechanism  70 . 
         [0035]    The handpiece  68  comprises a housing  94  shaped to be comfortably gripped and easily manipulated by a physician. Device  110  further includes ring  98  and flange  99 , which may be molded as part of the housing  94 , for facilitating handling of the device  110 , preventing drops of the device  110 , and/or facilitating quick hand-off of device  110  to an assistant, for example. 
         [0036]    An encoder or other method of monitoring the number of motor revolutions may optionally be included. An output gear may either drive the lead screw or the nut. In a particular embodiment, a ball screw is provided for this application, providing a high efficiency for use with less robust transmission components, that is, for example, a smaller motor, a smaller battery and electronics. It can be appreciated that a less efficient screw may be used if the motor has sufficient power to overcome the losses. 
         [0037]    Alternative handpiece housings  116   a,    116   b  and  116   c  are shown in  FIGS. 3A-3C , including various rings  106  and grips  108  for either the thumb location and/or finger location(s). Each of housings  116   a,    116   b  and  116   c  includes a distal end  120   a ,  120   b,    120   c,  respectively, structured to be coupled to a syringe (not shown) as described and shown elsewhere herein, and a proximal end  122   a,    122   b,    122   c , respectively, which may include switch  70  as described and shown elsewhere herein. These housings  116   a,    116   b,    116   c,  and permutations thereof, may be used as a part of any of the embodiments of the invention described herein, for example, device  10  and  110 , with appropriate modification as needed. 
         [0038]      FIGS. 4A and 4B  show perspective views of an optional coupler  210  of the invention.  FIGS. 5A-5C  show cross-sectional views of the coupler  210  shown in  FIGS. 4A and 4B . 
         [0039]    Optional coupler  210  may comprise clip  212  which provides a means of rigidly connecting a ball screw of the drive mechanism described elsewhere, with a plunger tip in the cartridge. The clip  130  allows the ball screw and plunger to be fixed together in order to facilitate reversing of the plunger in cartridge to achieve aspiration. A front end  218  of clip  212  connects to the plunger tip  232  and both are disposed in syringe cartridge  226 . Clip  212  may be connected to plunger tip, for example, screwed into plunger tip  232  using threads  219 , or otherwise fixed thereto, or may be integral with plunger tip  232 . 
         [0040]    A rear portion  222  of the clip  212  features multiple features, for example, flared elements  224 , which in their unstressed state flare out slightly ( FIG. 4A ). The flared elements  224  provide a mating geometry to enable plunger rod  230  to slide into the clip  212 . The structure of the clip  212  is such that when the cartridge  226  is full with dermal filler gel, the flared elements  224  are located just outside the cartridge  226  of syringe  228  ( FIG. 5A ), and therefore allow mating between clip  212  and plunger rod  230  ( FIG. 5B ). As the device begins to inject, the plunger rod  230  mates with the clip ( FIG. 5C ) pushing the clip  212  and the plunger tip forward in the cartridge  226 . As the clip  212  moves forward the flares  224  get compressed by the inner diameter of the cartridge  226 , capturing the geometry of the plunger rod  230 . When the flares  226  are compressed, the plunger rod  230  and plunger tip  232  move as a single unit, either forward or backward. There may or may not be a rotational degree of freedom between these two parts. To remove the plunger rod  230  from the clip  212 , the plunger rod  230  can be pulled backward out of the syringe (pulling the clip  212  as it moves) until the clip  212  is far enough back such that the flares  224  will revert back to their “open” state. 
         [0041]      FIG. 5A  shows plunger rod disengaged from clip  212 ;  FIG. 5B  shows plunger rod moved forward to drive clip  212  forward down barrel/cartridge of syringe;  FIG. 5C  shows plunger rod engaged with clip  212 , allowing for forward or reverse motion. 
         [0042]    While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the invention.