Patent Application
20140336548
Attached please refer to the Information Disclosure Statement for the cross reference to related applications.
The present invention is not a federally sponsored research or development.
The present invention relates generally to the field of hypodermic injection of an agent for medical purpose. More specifically, the present invention provides an apparatus and methods to reduce pain and discomfort associated with an entry of both a needle and an injectable agent into tissue.
Injection of an agent into cutaneous and muscle tissues through a needle prick disrupts mechanical and chemical stability of the tissue and initiates a series of electrophysiological and biochemical cascade in the local tissue environment and in free nerve endings of nociceptive primary afferent nerve fibers embedded in the tissue. Cationic channels of the free nerve endings are activated, dependent on biophysical properties of both the needle prick and injected agent. Once voltage gated Na+ channels are activated, membrane depolarization of the nociceptor is propagated, resulting in release of intracellular Ca++. The increase in Ca++ concentration mediates cellular and microenvironmental changes to sensitize nociceptors of the free nerve endings. Furthermore, cells that are disrupted by needle prick could release membrane fatty acids which convert to prostaglandins. Increase in prostaglandins could intensify nociceptive response of the free nerve endings, which translates into intensified painful sensation by a subject.
The majority of the nociceptive signals generated by the free nerve endings are transmitted via both A-delta and C nerve fibers to superficial dorsal horn of the spinal cord. A-delta nerve fibers are responsible for initial sensation of sharp localized pain and C fibers are responsible for so-called second pain of burning and bruised feeling over a wider area than perceived by the A-delta fibers. A-delta fibers are known to be sensitized by intense heat, and high intensity and prolonged activation of C fibers are known to perpetuate the sensitization cycle of C fibers by producing ligands acting on release of pro-inflammatory molecules. At the spinal cord, both A-delta and C-fibers produce glutamate that is a key molecule for transmission of sensation of pain. Postsynaptic nociceptive input then travels upward from the spinal cord to various parts of brain.
There are inhibitory neuronal signals arising from various parts of the brain that descend in the spinal cord to modulate nociception. Descending inhibitory signals may be activated by external factors including stimulation on peripheral or central nervous system. In addition, there are ascending inhibitory signals, albeit minor, arising from parts of the brain. Descending inhibitory signals come to various neuronal structures of the dorsal horn of the spinal cord where downward postsynaptic changes inhibit nociceptive responses. It is believed that in human subjects the descending inhibitory signals can be physically activated by acupuncture, transcutaneous electric nerve simulation (TENS), vibration, dorsal column stimulation and deep brain stimulation.
Vibration is one of peripheral stimulation methods to reduce nociception, which include TENS, acupuncture, acupuncture-like TENS, electroacupuncture and acupressure. Exact mechanisms of analgesia induced by vibration have not been clarified yet but it is believed to be related to activation of A-beta primary afferent nerve fibers that inhibit segmental neurons of the dorsal horn of the spinal cord. It is also proposed that vibration stimulates both high-threshold A-beta fibers and A-delta fibers, which activates the descending inhibitory signals to suppress the dorsal horn neurons. Clinically, both TENS and vibration have been shown to reduce acute and chronic pain conditions, including low back pain, acute orofacial pain, causalgia, pain associated with vaginal delivery of baby and arthritic pain. In particular, vibration of cutaneous tissue of patients has been shown to reduce pain associated with needle prick and injection of agents into the tissue, thereby reducing requirement of anesthetic agents for minor procedures on skin and its appendages.
Various frequencies have been studied for vibration induced analgesia, ranging from 20 Hz to 300 Hz with a varying degree of effectiveness on analgesia. Additional issues of vibration such as duration, amplitude and effective area and depth under vibration have not been studied for its comparative effectiveness except that it appears that analgesia is achieved best in an area directly under vibration. Shortcomings of vibration are short duration of effects and potential development of tolerance over repetitive uses.
Needle-free injection systems using high-pressure jet-stream have been developed over a few years to reduce discomfort of needle prick necessary for injecting agents into tissue. However, needle-free injection disrupts mechanical and chemical stability of the tissue, which initiates similar electrophysiological and biochemical responses in nociceptive primary afferent nerve fibers to needle-based injection systems. Diffuse but limited dispersion from a site of entry of pressured jet-stream of the needle-free system inside the tissue along a longitudinal injection path may be the only advantage of the needle-free system to the needle-based system that produces a radially globular expansion of an injected agent from a tip of a needle inserted in the tissue. It is conceivable that globular expansion of the injected agent, compared to the longitudinally diffuse dispersion of the agent, may exert a more outward pressure per an area of the tissue, thereby disrupting a larger amount of mechanical connection of the tissue. However, one major drawback of the needle-free injection system is a risk of contamination of injection nozzle by recipient's tissue fluid that may emanate from an entry site of injection of the recipient. Unless each device is used only once for each recipient, it poses a significant hazard of transmission of potentially infectious agents such as hepatitis virus or human immunodeficiency virus (HIV) to other recipients receiving injection using the same device. Disposable needle-free injection systems would be available yet their cost-effectiveness cannot be compared favorably to simple disposable syringes and steel needles.
Intensity of nociception, i.e., pain sensation, associated with conventional hypodermic injection of an agent may be ameliorated by limiting extent of mechanical and chemical disruption of a target tissue and by activating descending inhibitory signals. Thinner and shorter hypodermic needles with a more acute angle of bevel may reduce the extent of mechanical disruption of the tissue. Stimulation of an injection site by vibration is one of available methods to activate the descending inhibitory signals. Successful implementation of vibration for achieving analgesia during the needle-based injection would require generation of a vibration field surrounding both a needle penetration site and a tissue infiltration site of an injected agent for an adequate length of time, adequate and redundant activation of primary afferent nerve fibers and fast diffusion of the injected agent from the tip of a needle to adjacent tissues without forming an outwardly pressured globule of the agent in an isolated area of the tissue. Yet the foremost importance should be given to a reproducible method of fail-safe delivery of an agent to a recipient without a risk of contamination by biologic fluids.
To achieve on-site placement of vibration surrounding a needle penetration site and a tissue infiltration site of an injected agent, adequate activation of adjoining primary afferent nerve fibers of the descending inhibitory signals by vibration, vibration-facilitated diffusion of an injected agent in the tissue and elimination of a risk of contamination of the apparatus by biologic fluids, the current apparatus comprises a vibration assembly, a mechanical assembly for syringe movement and a removable and disposable barrier that isolates the apparatus from recipient. The mechanical assembly further comprises a syringe holder assembly, a syringe propulsion assembly and a trigger assembly which is attached to a handle assembly. The handle assembly houses a electronic controller and a power source. A hypodermic needle of a syringe penetrates a tissue through a linear tubular conduit of the vibration assembly that contacts a skin of a recipient and delivers an injectable agent to the tissue while a field of vibration encircling the needle penetration site is applied to said tissue by the vibration assembly.
In one embodiment, the current apparatus is provided as a plurality of operating devices having one or a plurality of mechanical configurations. One of the configurations has a rectangular tubular body that is connected on a lower side of said tubular body to an elliptically tubular handle assembly at an angle to a longitudinal axis of said rectangular tubular body. A proximal end of the rectangular tubular body is connected to a vibration assembly and an upper side of said body houses a syringe holder assembly. A syringe propulsion assembly is housed longitudinally inside said body and is mechanically connected to the syringe holder assembly to slidably move the syringe holder on the upper side of said body along the longitudinal axis. A trigger assembly is attached to a front of the handle assembly, which initiates forward movement of the syringe propulsion assembly and retracts a needle from a recipient following completion of an injection.
In one embodiment, the vibration assembly, provided as one or a plurality of operating devices having one or a plurality of mechanical configurations, comprises a vibration generator and a vibration chamber which is connected to the vibration generator. The vibration chamber, provided in one or a plurality of mechanical configurations including a closed box configuration, contacts a recipient's skin and transmits vibration produced by the vibration generator to said skin and an underlying tissue. An upper part of the vibration chamber has an axially linear tubular conduit that runs from a distal end to a proximal end of said chamber. An aperture of the linear tubular conduit opens to a center of a recipient contact portion at the proximal end of the vibration chamber and the opposite side of said tubular conduit opens to the distal end of said chamber. The linear tubular conduit provides a hypodermic needle with a tubular passageway inside the vibration chamber to penetrate a tissue of a recipient.
In one embodiment, vibration is generated by an electromagnetic voice coil actuator with a moving coil, provided in one or a plurality of configurations, releasably and axially inserted in one or a plurality of cylindrical permanent magnets of said voice coil actuator. In a second embodiment, vibration is generated by an electromagnetic solenoid coil, provided in one or a plurality of configurations, releasably and axially inserted in one or a plurality of cylindrical permanent magnets. In another embodiment, vibration is produced by a vibratory electromagnetic motor provided as one or a plurality of mechanical configurations including an eccentric mass rotary motor or by an electromagnetic disc vibrator. A proximal end of the moving coil of the voice coil actuator, the vibratory rotary motor, or the disc vibrator is irreversibly attached to a vibration panel provided in one or a plurality of mechanical configurations including a diaphragmatic cone configuration. The vibration panel is attached to a part of the distal end of the vibration chamber and transmits vibration to the vibration chamber.
In one embodiment, a vibration chamber provides a resonant space in one or a plurality of mechanical configurations, which amplifies vibration in a certain range of frequencies generated by a vibration generator. A proximal end of the resonant space is configured to contact skin and to deliver resonated vibration. A distal end of the resonant space is configured to be attached to the vibration panel that transmits vibration to said resonant space. One of the mechanical configurations of the resonant space provides a natural frequency of said resonant space matched to a frequency range from 20 Hz to 300 Hz. The vibration chamber may or may not have a closed resonant space inside said chamber. A vibration chamber without a resonant space is configured as flat panel to which the vibration panel is directly attached.
In one embodiment, a moving coil of a voice coil actuator produces electromagnetic vibration in one or a plurality of frequencies ranging from 20 Hz to 20 kHz and of one or a plurality of amplitudes. In another embodiment, the voice coil actuator simultaneously generates vibration of multiple frequencies. Concurrent generation of multiple frequencies of vibration is meant to cover a wide range of nociceptive primary afferent nerve fibers which may have individually distinctive activation thresholds to different frequencies for activating inhibitory signals. Vibration amplitude is provided as adjustable to penetration depth of needle into tissue and to volume of injectable agent. A deeper penetration of a needle into a tissue and a larger volume of an injectable agent require a wider and deeper vibration field to sufficiently encompass the area of the injection, compared to a shallow penetration and to a smaller injection volume. Force of vibration is proportional to amplitude of vibration, which suggests that a higher amplitude is required to generate a larger force of vibration to cover a larger three-dimensional volume of a tissue that needs to be vibrated. Electromagnetic disc vibrator is also provided in one or a plurality of frequencies and with one or a plurality of amplitudes. The disc vibrator also is configured to simultaneously generate vibration of multiple frequencies. Vibratory eccentric mass rotary motor is provided in frequency that is variable.
In one embodiment, a control unit and a power source for the vibration assembly are housed in a handle assembly and connected electrically to the vibration generator. The control unit, provided as one or a plurality of electronic configurations, supplies the vibration generator an alternating or direct current and modulates both frequency and amplitude of vibration. The power source includes alternating current that is carried to the current apparatus from an external electric source or direct current from one or a plurality of batteries.
In one embodiment, a removable and disposable barrier, provided in one or a plurality of configurations, is insertably placed in the linear tubular conduit located in the vibration chamber along the longitudinal axis. One of the configurations includes a thin sheet of round or rectangular shape covering a recipient contact portion of the vibration chamber, which merges with a barrier tube inside the linear tubular conduit of the vibration chamber and gets connected to a round ring of said barrier located outside a distal end of said linear tubular conduit. The ring portion of the barrier protrudes distally from the distal end of the vibration chamber. The sheet is configured as thin membrane preferably made of a polymer and is indented on a recipient contact side. Indentations, provided as one or a plurality of configurations including linear indentation in a radial direction from a center of said sheet, are to facilitate folding of the sheet into a tubular configuration when the barrier is withdrawn through the linear tubular conduit from the proximal end to the distal end of the vibration chamber.
In one embodiment, a needle of a syringe coaxially enters a barrier tube releasably inserted in the linear tubular conduit of the vibration chamber through the ring portion of the barrier located at the distal end of said vibration chamber and protrudes from an open center of the sheet of the barrier located at the proximal end of said vibration chamber to penetrate a tissue of a recipient. Upon a full advancement of the needle for tissue penetration, the ring portion of the barrier circumferentially and adherently grabs a hub of the needle. Following completion of an injection, the needle coaxially retracts back out together with the adherent ring portion of the barrier from the linear tubular conduit of the vibration chamber. On retraction inside the linear tubular conduit of the vibration chamber, the sheet of the barrier is folded to form a longitudinally corrugated tubular sheet encircling the needle. Both the needle of the syringe and barrier are then discarded as a single unit. The barrier shields the vibration chamber with the linear tubular conduit from the needle during an entire cycle of penetration into and withdrawal of the needle from the recipient, thereby preventing contamination of the apparatus by biologic fluids of the recipient.
In one embodiment, a syringe attached to a needle is placed in a syringe holder assembly that is connected to a syringe propulsion assembly in one or a plurality of mechanical configurations. The syringe holder assembly, provided as one or a plurality of operating devices with one or a plurality of mechanical configurations, releasably encloses and slidably moves both the syringe and needle along the longitudinal axis of the apparatus on a top of the syringe propulsion assembly. In one mechanical configuration, the syringe holder assembly comprises a syringe holder and a syringe holder rail assembly. A syringe propulsion assembly comprises a syringe holder positioning assembly, a syringe holder thrust assembly and a plunger thrust assembly. The syringe holder rail assembly which is attached to a bottom of the syringe holder slides on the top of the syringe propulsion assembly to move back and forth a syringe and a needle. The syringe holder positioning assembly which is located at a distal end of the syringe holder reversibly advances said syringe holder longitudinally to secure the needle of the syringe inside the linear tubular conduit of the vibration chamber. Both the syringe holder thrust and plunger thrust assemblies, provided as one or a plurality of operating devices having one or a plurality of mechanical configurations, push the syringe holder and the plunger forward, respectively, by releasing compressed compression springs located at a distal end of each thrust.
In one embodiment, longitudinal sliding movement of the syringe holder is accomplished by a two-stage propulsion by the syringe propulsion assembly. The first stage is to position the needle of the syringe inside the linear tubular conduit of the vibration chamber by forwardly advancing the syringe holder positioning device. The second stage is to thrust both the syringe holder assembly and a plunger of the syringe toward the vibration chamber. Both the syringe holder assembly and the plunger of the syringe may be thrust either simultaneously or sequentially. Short syringes with small volume injectable may be thrust by a single propulsion mechanism using one or a plurality of compression springs axially placed behind a plunger of a syringe housed in the syringe holder. It may be advantageous for long syringes with large volume injectable to have separate propulsion mechanisms, with one mechanism for needle penetration to a tissue and the other for pushing a plunger to inject an agent into the tissue.
In one embodiment, propulsion of the syringe holder assembly is initiated by a mechanical trigger assembly with a trigger lever and a trigger bar, which is provided as one or a plurality of mechanical configurations. The trigger lever is attached to the handle assembly via a hinge joint and can be squeezed manually toward the handle assembly in pivoting movement about the joint. On an inner wall of the trigger lever, there is provided the trigger bar in one or a plurality of configurations, which is irreversibly attached to the inner wall of the trigger lever at an angle. Once the trigger lever is squeezed close to the handle assembly, the trigger bar comes in contact with a pawl lever of the syringe holder thrust and releases a ratchet of the syringe holder thrust from the pawl. The syringe holder thrust then is pushed forward by expansion of the compression spring located axially behind the syringe holder thrust. The plunger is pushed forward by similar expansion of the compression spring of the plunger thrust that is anchored by a separate pawl. A lever of the plunger thrust pawl is movably located behind the pawl lever of the syringe holder thrust and can be reversibly lifted by an incoming trigger bar to release a plunger thrust ratchet.
In one embodiment, the trigger assembly is configured to retract the syringe holder assembly for a distance following completion of an injection to pull out the needle from the recipient. On both sides of the trigger bar, there is provided a pair of connecting rods which connect the trigger lever to the syringe holder thrust. Each rod is rotatably connected to a hinge joint of the trigger lever and to another hinge joint of the syringe holder thrust. Both rods are horizontally connected to each other by a pair of horizontal bars. A horizontal bar of the rods at the trigger is located below the hinge joint of the trigger. The other horizontal bar of the rods at the syringe holder thrust is located above the hinge joint of the syringe holder thrust. Asymmetric placement of the horizontal bars above and below the hinge joints along the longitudinal axis of the connecting rods allows unobstructed movement of the trigger lever to the handle assembly. Upon a release of the trigger lever, the trigger connecting rods push back the syringe holder thrust for a distance by downward pressure on the hinge joint of the syringe holder thrust generated by the horizontal bar at said hinge joint.
Overview shows a schematic example of the apparatus of the present invention.
As described below, the present invention provides a vibration analgesia injection apparatus and methods of use. It is to be understood that the descriptions are solely for the purposes of illustrating the present invention, and should not be understood in any way as restrictive or limited. Embodiments of the present invention are preferably depicted with reference to
The overview shows a schematic three-dimensional illustration of an example of the apparatus.
Once the apparatus is turned on by the electronic controller switch 10, vibration are generated by the vibration generator inside the housing 4. The vibration is transmitted to the vibration chamber 1 and 3 where vibration of one or a plurality of frequencies is resonated. The vibration then is delivered to a tissue of a recipient through a proximal end of the upper vibration chamber 1. A syringe with a needle is housed inside the syringe holder 8, with its needle protruding through the front opening 6 of the syringe holder 8. Once the trigger assembly 13 is fully squeezed toward the handle assembly 12, the syringe holder 8 slidably is thrust to the upper vibration chamber 1 of the apparatus by a syringe propulsion assembly housed in the syringe propulsion assembly compartment 9. The needle of the syringe penetrates the tissue through the open aperture 2 of the linear tubular conduit in the upper vibration chamber 1. Following completion of an injection, the syringe with its needle is linearly withdrawn by a returning trigger assembly 13 back to an original position of said trigger assembly.
The handle assembly, provided as one or a plurality of operating devices having one or a plurality of mechanical configurations, comprises a pair of hinge joints 51 located at a proximal end of a bottom of the handle assembly on both sides, an inner handle divider 52, a battery pack 53, an outer wall of the handle 54 and a control electronics 55. The hinge joints 51 are rotatably connected with a trigger lever 50 of the trigger assembly. A trigger torsion spring 49 is inserted in a pivoting pin of each hinge joint 51 and exerts a circumferentially outward pressure on an inner wall of the trigger lever 50 and the inner handle divider 52. The battery pack 53 and the control electronics 55 are electrically connected to each other and to the voice coil actuator 19, and provide the voice coil actuator with electricity and electronic control on vibration for mode of vibration, frequencies and amplitudes. The batter pack 53 may be charged by wireless induction. A proximal end of the outer wall 54 of the handle is perforated to accommodate a trigger bar 46, a pair of trigger connecting rods 48 and a pair of the trigger torsion springs 49.
Shown in
The syringe propulsion assembly, provided as one or a plurality of operating devices having one or a plurality of mechanical configurations, comprises the plunger thrust assembly 28-31 and 36, the syringe holder positioner assembly 32-35 and the syringe holder thrust assembly in this particular schematic example. The syringe holder thrust assembly, provided as one or a plurality of operating devices having one or a plurality of mechanical configurations, comprises a syringe holder thrust 40, a syringe holder thrust guide shaft assembly 41 with a syringe holder thrust guide shaft 44, a syringe holder thrust ratchet 43 and a syringe holder thrust pawl 42. The syringe holder thrust ratchet 43, provided in one or a plurality of configurations including a toothed projection, protrudes from a bottom at a proximal end of the syringe holder thrust 40. The syringe holder thrust pawl 42, provided in one or a plurality of configurations, is attached to the syringe holder thrust guide shaft assembly 41. A compression spring is placed inside the syringe holder thrust 40 circumferentially wound around the syringe holder guide shaft 44 in front of the syringe holder guide shaft assembly 41 and provides forward movement of the syringe holder toward a proximal panel 45 of the syringe propulsion assembly compartment.
Forward movements of both the syringe holder thrust 40 and plunger thrust 28 are initiated by releasing both the ratchets 43 and 36 from the pawls 42 and 35, respectively. Release of both the ratchets 43 and 36 is accomplished by the trigger assembly. The trigger assembly, provided as one or a plurality of operating devices having one or a plurality of mechanical configurations, comprises the trigger lever 50, the trigger bar 46 with its trigger bar tip 47, a pair of the trigger connecting rods 48, a pair of horizontal bars (shown in
In one embodiment, a forward positioning of the syringe holder 8 by a forward movement of the syringe holder positioner 32 vertically aligns a distal knob of the plunger thrust pawl 35 with a distal knob of the plunger thrust pawl release lever 38. The trigger lever 50 then is manually squeezed by an operator toward the outer wall 54 of the handle assembly. The trigger bar 46 advances distally toward a distal end of the apparatus and the trigger bar tip 47 pushes back the distal end of the syringe holder thrust pawl 42, thereby releasing the ratchet 43. At the same time, the distal end of the syringe holder thrust pawl 42 pushes down the proximal knob 39 of the plunger pawl release lever. Circumferentially downward movement of the plunger pawl release lever rotates the distal knob 38 of said plunger pawl release lever in a counterclockwise direction about the pivoting center of said plunger pawl release lever. The counterclockwise rotation of said distal knob 38 pushes up the distal knob of the plunger thrust pawl 35. Circumferentially upward movement of the distal knob of the plunger thrust pawl 35 about its pivoting center releases the ratchet 36. Release of both the ratchets 43 and 36 allows forward movement of both the syringe holder thrust and plunger thrust.
Depending on a distance between the distal end of the syringe holder thrust pawl 42 and the proximal knob 39 of the plunger pawl release lever, forward movement of both the syringe holder thrust and plunger thrust can be timed simultaneously or sequentially. The forward movement of the syringe holder thrust 40 makes the needle 26 penetrate a tissue of a recipient. The forward movement of the plunger thrust 28 pushes the plunger 27 toward the tip of the syringe, thereby delivering an injectable agent to the tissue. In one embodiment, the present apparatus may have the plunger thrust assembly and the syringe holder positioner assembly without the syringe holder thrust assembly. In another embodiment, the apparatus comprises the syringe holder thrust assembly, the plunger thrust assembly and the syringe holder positioner assembly, provided with both the distal end of the syringe holder thrust pawl 42 and the proximal knob 39 of the plunger pawl release lever separated by one or a plurality of distances from each other. Short syringes with a small volume injectable may be thrust by a single propulsion mechanism with the plunger thrust assembly. It may be advantageous for long syringes with a large volume injectable to have both the syringe holder thrust assembly and plunger thrust assembly, with one mechanism for needle penetration to a tissue and the other for pushing a plunger to inject an agent into the tissue.
The apparatus controls depth of needle in a tissue, provided by one or a plurality of operating devices having one or a plurality of mechanical configurations. In one embodiment, on a distal surface of the proximal panel 45 of the syringe propulsion assembly compartment, a needle depth control thread 56 is axially installed with a spiral needle depth control knob 57. The spiral needle depth control knob 57 is accessible from outside the syringe propulsion assembly compartment and is spirally joined in parallel with the spiral needle depth control thread 56. Rotation of the spiral needle depth control knob 57 rotationally moves the needle depth control thread 56 away from or toward the proximal panel 45, dependent on handedness of the spirals. Distance between the distal surface of the proximal panel 45 and a proximal end of the syringe thrust 40 is adjustable by moving the needle depth control thread 56 away from or toward the proximal panel 45.
The syringe holder 8 can be lifted open by a longitudinal syringe holder knob 58 located on a bottom on one side of said syringe holder 8.
It is to be understood that the aforementioned description of the apparatus and methods is simple illustrative embodiments of the principles of the present invention. Various modifications and variations of the description of the present invention are expected to occur to those skilled in the art without departing from the spirit and scope of the present invention. Therefore the present invention is to be defined not by the aforementioned description but instead by the spirit and scope of the following claims.
