Abstract:
An improved medical device for injecting a local anesthetic into an organism. The device comprises a needle, an injection tube attached to the posterior end of the needle, a plunger attached to the posterior end of the needle, a housing dimensioned so that the plunger slides through the housing with friction, and a conduit dimensioned to allow the needle to pass through. The device allows an anesthesia provider to perform a nerve block more safely and efficiently. In one embodiment of the device, the nerve block can be performed without an assistant.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit, under 35 U.S.C. §119(e)(1), of U.S. provisional patent application No. 60/968,166 filed on Aug. 27, 2007, titled “A Regional Anesthesia Needle Assembly for an Easy and Safe Performance of a Nerve Block.” 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to medical devices for injecting fluid solutions into an organism and more particularly to medical devices for injecting a local anesthetic. 
       BACKGROUND 
       [0003]    A nerve block is a procedure in which an anesthesia provider will place a special insulated needle in very close proximity to a nerve within the human body and perhaps animals. A local anesthetic solution is injected through the needle and around the nerve in order to provide anesthesia and pain relief in an area of the body which is innervated by the targeted nerve. 
         [0004]    In order to accomplish this procedure correctly, a majority of anesthesia providers use traditional nerve block needles which consist of an insulated steel shaft needle. At the rear end the needle is attached to an injection tube and a conductive wire. 
         [0005]    A small battery-operated nerve stimulator device is attached to the rear end of the conductive wire. The anesthesia provider will advance the needle through the skin toward the targeted nerve. An assistant operates the nerve stimulator by sending decreasing amounts of electric current through the needle, causing a specific muscle contraction. This contraction indicates the proximity of the needle to that specific nerve. Then the assistant injects the local anesthetic solution into the injection port. The solution goes through the tubing and the needle to be deposited near the desired nerve. 
         [0006]    During the whole procedure the anesthesia provider needs both hands to keep the needle in a constant direction and depth, and also to advance the needle very gently and smoothly. This process is necessary in order to prevent nerve injury or accidental injection of the medicine inside a blood vessel or a nerve. Either one of which can have grave consequences. 
         [0007]    It is known in the art that performance of a nerve block: (1) is a very delicate procedure, (2) can be time consuming, (3) takes a great amount of practice to master, (4) almost always requires the presence of an assistant, (5) can have a significant failure rate, (6) can result in the fatigue of the anesthesia provider&#39;s hands, arms, and back, (7) can result in accidental nerve injury or intravascular injection which can lead to grave consequences such as seizure, coma, and even death, (8) the needle can become dislodged as a result of the slightest hand movements, and (9) has the potential to cause needle injury to the anesthesia provider and medical assistants. 
         [0008]    Today, more and more people are using ultrasound imaging devices to help them visualize the nerve during the performance of a nerve block. This requires use of bulky and expensive devices which will not eliminate the need for an assistant. 
         [0009]    There is a need in the field for a medical device for injecting a local anesthetic that reduces the risk of the negative outcomes mentioned above, is easier to use than similar devices in the field today, and has the potential of allowing an anesthesia provider to effectively locate a nerve and inject the local anesthetic without the use of an assistant. 
       SUMMARY 
       [0010]    The present invention is directed to a device that satisfies these needs of reduction in the risk of negative outcomes associated with nerve block procedures, making the nerve block procedure easier to perform, and creating the potential for allowing an anesthesia provider to effectively inject the local anesthetic without the use of an assistant. The device generally comprises a conventional regional anesthesia needle, a plunger, an injection tube, an injection port, a housing and a conduit. The injection port and the needle being attached to opposite ends of the injection tube. The housing is shaped with dimensions that allow the plunger to slide inside the housing with a certain amount of friction created between the plunger and the housing. The conduit is positioned at the front opening of the housing. The conduit guides the needle as the needle moves from a position where the needle&#39;s length is inside the housing to a position where needle is projecting out from the front of the housing. 
         [0011]    In an alternative embodiment, present invention further comprises an injection pad. The base of injection pad is coated with a sticky material that allows the injection pad to be temporarily attached to the patient&#39;s skin. The injection port at the end of the injection tube is attached to the top surface of the injection pad to provide stable injection port so that the anesthetic solution can be single-handedly directed into the injection tube. 
         [0012]    In order to place a nerve block, the anesthesia provider holds the conduit between the thumb and index finger. The conduit front end is rested against the patient&#39;s skin over the targeted nerve. The conductive wire is attached to the nerve stimulator. The anesthesia provider uses one hand to constantly hold the conduit against the patient&#39;s skin. The other hand is used alternatively to advance the plunger and also to operate the nerve stimulator. By advancing the plunger, the needle inside the housing moves toward the targeted nerve. After the targeted nerve is located, the anesthesia provider has the option of using an assistant to inject the local anesthetic solution into the injection port, or as it was described in the above alternate embodiment, the provider can use the specifically designed injection pad to single handedly inject the local anesthetic into injection port. 
         [0013]    At the end of the procedure, the anesthesia provider will retract the plunger and hence the needle inside the housing, and disposes of the needle safely. This will reduce the risk of needle injury to the anesthesia provider and other medical personnel. 
         [0014]    These and any other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. 
     
    
     
       DRAWINGS 
         [0015]      FIG. 1  shows a prior art nerve block needle. 
           [0016]      FIG. 2  shows a sectional side view of a version of the plunger for the invention. 
           [0017]      FIG. 3  shows a sectional side view of a version of the housing for the invention. 
           [0018]      FIG. 4  shows a sectional side view of a version of the invention. 
           [0019]      FIG. 5  shows a sectional side view of a version of the invention. 
           [0020]      FIG. 5   a  shows a sectional side view of a version of the conduit for the invention. 
           [0021]      FIG. 6  shows a sectional side view of a version of the plunger for the invention. 
           [0022]      FIG. 7  shows an exploded sectional side view of a version of the plunger for the invention. 
           [0023]      FIG. 8  shows a plan horizontal view of a version of the injection pad for the invention. 
           [0024]      FIG. 9  shows a sectional side view of a version of the injection pad for the invention. 
       
    
    
     DESCRIPTION 
       [0025]    Referring to  FIG. 1 , a conventional nerve block device is comprised of a hollow needle  30  that is connected to an injection tube  34  and a conductive wire  36 . The injection tube  34  has an injection port  37  at its posterior end. The injection port  37  is used to introduce the local anesthetic into the injection tube  34 . The posterior end of the conductive wire  36  may be connected to a battery operated nerve stimulator device. The conductive wire  36  enables pulses of electricity to be sent through the needle  30  in order to determine the distance between the needle  30  and the nerve that the anesthesia provider desires to block. 
         [0026]    In the preferred embodiment of the plunger  40  shown in  FIG. 2 , the plunger  40  comprises a shaft  32 , a posterior knob  38 , and an anterior ring  33 . The needle  30  is mounted to the front side of the anterior ring  33 . Conductive wire  36  and the injection tube  34  are threaded through the shaft  32  and exit the posterior end of the shaft  32 . The plunger  40  can be constructed out of any solid material, but is preferably made of plastic. 
         [0027]    In the embodiment of the housing  10  shown in  FIG. 3 , the housing  10  comprises a cylindrical body  12 , a anterior end  14 , and posterior end  16 . The housing  10  has a finger flange  18  at its posterior end  16 . The conduit  15  is attached to the anterior end  14  of the housing  10 . A rear stop flange  20  and a front stop flange  22  are positioned inside the housing  10 . The rear and front stop flange  20 ,  22  maintain the plunger  40  inside the housing  10 . The housing  10  can be any shape, but is preferably cylindrical. In addition, the housing  10  can be made of any solid material, but is preferably made of clear plastic to allow the user to see the needle  30  inside the housing  10 . 
         [0028]    Referring to the embodiment of the invention shown in  FIG. 4 , the plunger  40  is inserted into the chamber  10  in such a way as to allow the needle  30  to pass through the conduit  15 . The internal diameter of the conduit  15  is made slightly larger than the outer diameter of the needle  30 . This allows the needle  30  to pass through the conduit  15  in a guided fashion. The anterior ring  33  of the plunger  40  is placed between the front and rear stop flange  20  and  22 . The injection tube  34  and the conductive wire  36  are threaded through the shaft  32  of the plunger  40 . The posterior knob  38  of the plunger  40  is used by the anesthesia provider to force the needle  30  through the conduit  15  and into the organism that will receive the local anesthetic. 
         [0029]    Referring to the embodiment of the invention shown in  FIG. 5 , a locking mechanism  80  may be attached to the housing to lock the needle in a position. The embodiment of the locking mechanism shown in  FIG. 5  comprises a shaft  82 , a knob  86 , and a break pad  84 . The shaft  82  and knob  86  can be made of any solid material like plastic or metal. The shaft  82  is threaded on the surface and functions like a standard bolt. The break pad  84  can be made of any elastic material such as rubber. As shown in  FIG. 5 , the embodiment of the locking mechanism  80  comprises a threaded nut  88 . The threaded nut  88  functions like a standard hardware nut thereby allowing the shaft  82  to be screwed in and out of the threaded nut  88 , thereby moving the break pad  84  up to and away from the plunger inside the housing. 
         [0030]    Referring to the embodiment of the invention shown in  FIG. 5   a,  the locking mechanism can comprise a conduit at the front of the housing that is made of a soft, elastic material such as plastic or rubber. When a user applies pressure to the conduit, the conduit narrows and creates friction against the needle. Applying pressure in this way allows the user to hold the needle in a desired position. By releasing the pressure, the user can then move the needle again. 
         [0031]    In an alternative embodiment of the invention shown in  FIGS. 6 and 7 , the invention comprises a fine tuning mechanism. As illustrated in  FIGS. 6 and 7 , the embodiment of the plunger  40  comprises two hollow cylinders  52 ,  54 . The inner cylinder  52  is threaded on its outer surface, and the outer cylinder  54  is threaded on its inner surface. They function like a standard bolt and nut. The two cylinders  52 ,  54  move telescopically against each other by twisting both cylinders  52 ,  54  in opposite directions. In practice, the outer cylinder  54  is locked into place against the housing using locking mechanism  80 . A user then rotates the inner cylinder  52  using the knob  38  that is attached to the inner cylinder  52 . The rotation of the inner cylinder  52  causes the inner cylinder  52  to advance forward, away from the outer cylinder  54 . Since the needle  30  is attached to the inner cylinder  52 , the needle  30  advances in a forward direction. The fine tuning mechanism allows a user to achieve very fine movements of the needle  30  when the needle  30  is inserted into the organism. 
         [0032]    An alternative embodiment of the invention comprises an injection pad. Embodiments of the injection pad are illustrated in  FIGS. 8 and 9 . Referring to  FIG. 8 , the injection pad  60  can be made of any flexible material such as plastic or rubber. The injection pad  60  has a top surface  64  and a bottom surface  62 . An injection port  37  is attached to the top surface  64  of the injection pad  60 . The bottom surface  62  is covered with a layer of adhesive substance, which is preferably covered with a removable backing. When a user removes the backing, the injection pad  60  can be attached to a patient&#39;s body or any available surface near the patient. The injection pad  60  provides a stable, immobile injection port  37 , which allows the anesthesia provider to single-handedly attach, inject, and detach syringes of local anesthetics into the injection port  37 . The injection pad  60  can be made in any size and shape, but is preferably made in the shape of a disc or square.