United States Patent c19J
`Spinello
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,747,824
`May 31, 1988
`
`[76]
`
`[54] HYPODERMIC ANESTHETIC INJECTION
`METHOD
`Inventor: Ronald P. Spinello, S23 Post Ave.,
`Westbury, N.Y. 11590
`[21] Appl. No.; 868,745
`[22] Filed:
`May 30, 1986
`Int. CJ.4 ............................................. A61M 31/00
`[51]
`[52] U.S. Cl . ...................................... 604/51; 604/207;
`604/1S4; 433/89
`(S8] Field of Search ................. 604/S1, 1S2, 154, 207,
`604/228, 20;433/84-8S, 89-90, 119
`References Cited
`U.S. PATENT DOCUMENTS
`3,395,704 8/1967 Frey et al ............................ 604/154
`3,924,335 12/1975 Balamuth et al .................... 433/119
`3,971,375 7/1976 Hill ...................................... 604/207
`4,141,359 2/1979 Jacobsen et al ....................... 604/20
`
`(56]
`
`4,323,066 4/1982 Bourdon ............................. 604/228
`4.597, 754 7 /1986 Thill et al. ............................ 604/51
`Primary Examiner-C. Fred Rosenbaum
`Assistant Examiner-Gene B. Kartchner
`Attorney, Agent, or Firm-Hoffmann & Baron
`ABSTRACT
`[S7]
`A method and apparatus for effecting painless hypoder(cid:173)
`mic needle administration of liquid anesthetics particu(cid:173)
`larly in dentistry in which the needle is carried on a
`light wand and the anesthetic is delivered to the needle
`by motive means independently of the operator's fingers
`during penetration of the needle, with both the rates of
`penetration and expression of liquid being controlled to
`achieve intermediate numbing followed by a high rate
`of liquid expression, if desired, to achieve full anesthesia
`of the site.
`
`4 Claims, 3 Drawing Sheets
`
`Sanofi Exhibit 2170.001
`Mylan v. Sanofi
`IPR2018-01676
`
`

`

`U.S. Patent May 31, 1988
`
`Sheet 1 of 3
`
`4,747,824
`
`FIG. IB
`
`FIG. IA
`
`R
`
`8
`FIG. 2A
`
`Sanofi Exhibit 2170.002
`Mylan v. Sanofi
`IPR2018-01676
`
`

`

`U.S. Patent May 31, 1988
`
`Sheet 2 of 3
`
`4,747,824
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`4.0
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`3.0
`+
`2.0
`
`1.0
`.5
`
`FIG. 3
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`8-20 SEC.
`
`/
`
`/
`2-5SEC.
`
`,,--
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`/
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`/
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`/
`
`2-20 SEC.
`
`TIME
`
`·
`
`IZ~
`
`15
`
`FIG. 4
`
`15../
`
`Sanofi Exhibit 2170.003
`Mylan v. Sanofi
`IPR2018-01676
`
`

`

`U.S. Patent May 31, 1988
`
`Sheet 3 of 3
`
`4,747,824
`
`- - - - - - 1
`
`z,;
`►
`
`22b
`
`22
`
`MICRO
`CONTROLLER
`CIRCUIT
`
`STEPPER
`MOTO.~
`DRIVER
`CIRCUIT
`
`ROM
`CIRCUIT
`
`Z7
`
`ENUNCIATOR
`
`3/
`
`- - - - '
`
`FIG. 5
`
`==--=-=- =-----:=------------=-----==-= j
`==~-= =---------- -=---= -::.. -:. --=----=- =- -
`
`45
`
`FIG. 6
`
`Sanofi Exhibit 2170.004
`Mylan v. Sanofi
`IPR2018-01676
`
`

`

`1
`
`4,747,824
`
`HYPODERMIC ANFSI'HETIC INJECTION
`METHOD
`
`2
`aligned end on end and interconnected at each end by a
`synapse. When a stimulus is applied to a nerve ending,
`an electrical impulse or signal is transmitted from nerve
`cell to nerve cell and regenerated across each synapse,
`This invention relates to hypodermic anesthestic in(cid:173)
`5 until it reaches the brain, where it is interpreted as pain,
`cold, hot, etc. When a local anesthetic solution is ap•
`jection apparatus and methods, particularly as applied
`to dentistry.
`plied to a nerve, it blocks the signal transmission. The
`brain therefore receives no sensory information from
`BACKGROUND OF THE INVENTION
`the part affected by the anesthetic. At the cellular level
`Almost 100 years ago the excruciating pain of dental 10 this effect is immediate. It is believed that it occurs
`extraction, drilling and reconstruction was eliminated
`when the anesthetic comes in contact with a nerve part,
`by the invention of local anesthetics. Ever since, how-
`rendering it instantly inoperative.
`ever, one smaller but often agonizing pain has remained;
`It is the object of dental injections to render the nerve
`ironically, it is the pain of the hypodermic injection
`bundles which supply the teeth and supporting struc-
`itself. All practical attempts to eliminate it have failed. 15 tures free of pain sensation. These nerve bundles pass
`While narrow gauge, sharp hypodermic needles can be
`from the brain through the jaw bone to the teeth and
`gums. In instances in which the bone is spongy such as
`inserted into the soft fleshy tissues of say an upper arm
`essentially without pain save possible psychological
`in the upper jaw (maxilla) the anesthetic can be placed
`pain, the pain of a hollow needle inserted into the hard,
`at the outside bone surface adjacent to the tooth. The
`relatively inelastic gum and mouth tissues to engage the 20 solution is absorbed by the porous bone and infiltrates
`bone which carries the nerves to the teeth, is more often
`to the tooth nerve. In other instances where the jaw
`than not real. It is also complex. Pain can be felt when
`bone is dense as it is in the lower jaw (mandible), the
`the needle first punctures the firm tissue and thereafter
`dentist must either block the nerve before it enters the
`as the needle tip cuts through the tissue. Pain can be felt
`jaw or he may attempt to force the anesthetic into the
`if the needle scrapes the bone membrane and even 25 ligament space between the tooth root and the bone.
`greater pain can be felt if the injected liquid mass dis-
`In all cases there is a delay before the anesthetic solu-
`tends and tears the tissue, particularly the interior tissue,
`tion penetrates through the various tissues, and until it
`away from the bone in one of the most sensitive por-
`disables all of the fibers in the nerve bundle. During the
`tions of the body, before absorption and numbing occur.
`injection procedure the needle point severs through
`And pain can be felt if either the dentist or the patient or 30 tissues which contain live nerve endings causing pain,
`both are not steady, causing traumatic lateral displace-
`the injected anesthetic solution stretches these same
`tissues causing pain, and if the needle is moved laterally
`ment of the embedded needle.
`The present state of the art in hypodermic anesthetic
`in these same tissues, it causes pain, all before the nerves
`injections, particularly dental injections, is at best a hit
`in the main trunk are blocked.
`or miss art reflecting the skill and luck of the operator 35
`The present invention provides a means whereby the
`rather than being a scientifically repeatable procedure.
`nerves are disabled in the area of the injection and in the
`The tools are clumsy and ill-suited to their task, making
`path of the needle before pain sensation is perceived.
`the administration of local anesthetics in dentistry one
`The needle is held in a stabilized trajectory and ad-
`of the less pleasant procedures for both the dentist and
`vanced slowly at a rate preferably, for example, not to
`the patient alike.
`40 exceed 6 mm/sec. through the tissues, and a flow of
`The present invention has for its object to eliminate
`anesthetic solution is established concomitantly at a
`constant slow rate of 0.25 to 1.0 cc. per minute, sur-
`pain in all phases of and for all types of hypodermic
`anesthetic injection including four in dentistry consid-
`rounding the moving needle with a sheathing of anes-
`ered most difficult and painful: the palatal, the mandibu-
`thetic solution. Since nerve disability is instantaneous,
`lar, the interligamentary, and the maxillary anterior.
`45 needle penetration cannot be perceived as pain. When
`Another object of the invention is to provide a facto-
`the needle reaches bone, if the constant and painless rate
`ry-sterilized, assembled and sealed hypodermic syringe
`of flow of anesthetic is continued, tissue numbness oc-
`sub-assembly of needle, handle and anesthetic vial, fully
`curs prior to tissue stretching. Once the surrounding
`charged with anesthetic to provide an unbroken chain
`tissues have been rendered numb, the rate of flow can be
`of sterility from manufacture to patient.
`50 increased to expedite the procedure.
`Another object of the invention is to provide a uni-
`The instrument in accordance with one preferred
`versal hypodermic syringe which can be used for all
`embodiment of the invention, includes a low-inertia
`known dental injection procedures, which is pleasant
`needle and elongated handle assembly either connected
`and easy to use and which affords the dentist extraordi-
`by a flexible conduit to an anesthetic vial, or itself con-
`narily acute tactile response characteristics essential to 55 taining an anesthetic vial, all of which can be pre-steril-
`good dentistry.
`ized and disposable; stabilizing means for referencing
`Another object of the invention is to provide a local
`needle movement and position to the site; and an activa-
`anesthetic injection apparatus and method which re-
`tor or pump to expel extremely small volumes of anes-
`duces the amount of anesthetic required to perform
`thetic at a controlled rate, from the vial to the needle tip
`dental procedures.
`60 and, selectively, relatively larger volumes at high flow
`rates.
`The needle assembly can comprise a narrow pencil-
`grip handle to allow the thumb and forefinger of the
`operator to implant the needle delicately to sense the
`essential proximity to bone while the other fingers stabi(cid:173)
`lize the needle assembly against a fixed reference such
`as the teeth. In the case of the mandibular injection
`which is deep in the sides of the mouth at the ascending
`
`BRIEF DESCRIPTION OF THE INVENTION
`Nerves exit from the brain as large bundles or trunks.
`Much like a tree, the major nerves branch into smaller
`bundles. This branching continues until finally the 65
`nerves become individual fibers and spread in and
`around the cells of most all tissues in the body. On a
`microscopic level each nerve fiber is composed of cells
`
`Sanofi Exhibit 2170.005
`Mylan v. Sanofi
`IPR2018-01676
`
`

`

`3
`ramus of the lower jaw bone and which seeks a small
`window in the bone to the large bundle of interior
`nerves serving all lower teeth, the handle can be stabi(cid:173)
`lized to the lower jaw, either by the fingers of the den(cid:173)
`tist or by a bite block, thus relieving the dentist of the 5
`fatigue attendant a large volume (about 2 cc.) injection
`over a period of up to one minute. The needle can be
`moved axially for a controllable distance and direction
`without the loss of sensitivity by the fingers holding the
`unit. If desired, a movable pressure pad and needle 10
`guiding and shielding tip can be used to pre-engage the
`injection site as the needle is moved through it into the
`tissue, or it can be manually moved to expose only as
`much of the needle as is required for the injection.
`The expression of extremely small amounts of the 15
`liquid anesthetic from the needle tip is critical at the
`outset of the injections. It is difficult if not impossible to
`achieve consistently low flow rates using a conven(cid:173)
`tional thumb-actuated syringe, particularly while the
`needle tip, invisible to the dentist, is cutting through the 20
`tissue. In accordance with the invention, an initial flow
`rate on the order of 0.25 to 1.0 cc. per minute or approx(cid:173)
`imately 0.5 to 1.5 drops per second (from a 30 gauge
`needle) is generated beginning not later than the outset
`of the initial needle penetration. This can be best 25
`achieved by separating the liquid pumping function
`from the hand which performs the needle implant. A
`foot-controlled motor is one preferred embodiment in
`which the motor is of variable speed and in which the
`anesthetic pumping action is bi-directional to achieve 30
`the essential test to determine that the needle is not
`implanted in a vein or artery when the high injection
`rate begins. The pumping action can be arranged so that
`the pressure of the anesthetic is reduced below the pa(cid:173)
`tient's blood pressure for a controlled interval, briefly 35
`and automatically for one or more times during each
`injection and in any event at the instant ·before high
`volume pumping begins in a fixed spot. This allows
`visible blood to flow into a viewing capillary in the
`syringe in the event the tip is implanted by error in a 40
`vein or artery.
`
`···
`
`··
`
`4,747,824
`
`4
`but at the expense of increased size and weight, and it
`lacks any way of achieving back-flow to test for inser(cid:173)
`tion of the needle into a vessel. Also, the stored energy
`in the resilient (or elastomeric) container is such that
`maximum pressure and flow occur at the outset and
`decrease with time, which is the opposite of that which
`is required in accordance with the present invention.
`U.S. Pat. No. 966,128 discloses a power syringe adapted
`to be connected by a flexible rotating shaft to a dental
`lathe so that the dentist is freed from delivering the
`pumping forces. It does not disclose the method or
`apparatus whereby low, precision-controlled flow rates
`are established concomitantly with needle penetration,
`nor are selective high and low expression rates sug(cid:173)
`gested. Overall, the prior art does not teach the combi(cid:173)
`nation of structures or the method which renders hypo(cid:173)
`dermic anesthetic procedures repeatably painless and
`efficient for all types of injections.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIGS. lA and 1B are diagrammatic representations
`in enlarged scale and in cross section illustrating the
`method of the invention as applied to one form of dental
`anesthesia;
`FIGS. 2A and 2B are diagrammatic representations
`in enlarged scale and in cross section illustrating the
`method of the invention as applied to an interligamen(cid:173)
`tary dental anesthetic injection;
`FIG. 3 is an anesthetic flow rate vs. time graph show(cid:173)
`ing representative values for carrying out the invention;
`FIG. 4 is a drawing partly in cross section illustrating
`an expendable sterile pre-charged anesthetic and sy(cid:173)
`ringe kit in accordance with the invention;
`FIG. 5 is a schematic diagram partly in cross section
`illustrating one form of apparatus in accordance with
`the invention; and
`FIG. 6 is a schematic diagram illustrating another
`embodiment of the invention.
`
`DESCRIPTION OF PREFERRED
`EMBODIMENTS
`The method of the present invention is described
`BRIEF DESCRIPTION OF THE PRIOR ART
`having reference to FIGS. 1 through 3. In FIGS. 1A
`and IB the hollow pointed needle of a hypodermic
`The sources of pain in hypodermic injections have
`long been recognized. Dental schools for example, 45 syringe 10 is shown penetrating the soft gingival tissue
`teach care and steadiness in implanting the needle at
`T covering the bone B in which the root of a tooth (not
`precise locations, the need to achieve reverse flow to
`shown) is imbedded. Prior to insertion of the needle into
`prevent injection of anesthetic directly into a vein, and
`the tissue the syringe is filled with liquid anesthetic to
`an undefined slow injection rate, at least at first until
`the point at which a small drop appears at the opening
`numbness is achieved. The classic syringe instrument 50 in the tip of the needle. A flow rate for the anesthetic is
`for doing all of this, a direct derivation from the medical
`then established through the needle in the range of 0.25
`intramuscular, subcutaneous and intravenous syringes,
`to 1.0 cc. per minute by means of apparatus described
`puts a heavy essentially unachievable burden on the
`below. As the needle pierces the tissue preferably at a
`dentist if the procedure is to be painless. The instrument
`rate of penetration not exceeding 6 millimeters per sec-
`is too heavy and it is held incorrectly to reflect optimum 55 ond, anesthetic is expressed continuously and uniformly
`tactile sensations between the needle and the fingers of
`from the needle resulting in a sheath 11 of anesthetic
`the dentist. It is all but impossible to achieve the uni-
`from in front of the tip rearward which anesthetizes the
`formly low flow rates called for by the present inven-
`path of travel of the needle rendering the insertion pain-
`tion. U.S. Pat. No. 1,046,166 suggests separating the
`less. When the needle reaches its desired position adja-
`anesthetic pumping and needle implanting functions by 60 cent the bone, the relatively low continuous rate of
`using the foot to pump the liquid. It achieves pressures
`anesthetic expression is continued creating a plume Ila
`beyond those achievable by the thumb to force the
`constituting an expanded zone of tissue which is anes-
`liquid into the tooth dentin, but is not concerned with
`thetized due to infiltration of anesthetic into the soft
`low inertia, low precision-controlled flow rates and the
`tissue and the bone. This portion of the injection is
`combination of needle insertion and preliminary expres- 65 termed "intermediate".
`sion of anesthetic. U.S. Pat. No. 3,496,937 recognizes
`Referring to FIG. 3, this initial period of relatively
`the advantage of a pencil grip and of at least partially
`low level anesthetic expression rate constituting the
`freeing the thumb from the axial-thrust pumping action
`intermediate injection is shown on the time-rate graph
`
`Sanofi Exhibit 2170.006
`Mylan v. Sanofi
`IPR2018-01676
`
`

`

`4,747,824
`
`s
`6
`housed in a transparent plastic container 17 sealed by a
`as taldng between 8 and 20 seconds, depending on the
`removable cap 18. The container includes a resilient rib
`injection site and the particular requirements of the
`19 by means of which it can be mounted in the pumping
`patient.
`apparatus of FIGS. 5 or 6 as described below.
`After the initial period of 8 to 20 seconds of low-rate
`The initial charge of anesthetic can if desired fill the
`injection of anesthetic the surrounding area becomes 5
`tubing 15, the handpiece through-bore 12a and the hol-
`sufficiently anesthetized to enable the operator to in-
`low needle 14. With the sheath 14 and cap 18 in place
`crease the rate of flow to 2 to 4 cc. per minute until the
`the entire assembly can be factory-sterilized and sealed
`desired degree of numbing is achieved. Such high rates
`in a pouch for opening in the presence of the patient and
`of anesthetic expression normally cause pain due to
`stretching ~d tearing of _the. tissues, ~ut havin~ b~n 10 discarded after one use. The sheath 14 includes a pierce-
`able membrane 14a at its outer end so that it can be slid
`pre-anesthettzed no sensation IS felt. Pnor to begmrung
`th~ high rate of injection a nega~ive pressur~ relative to
`down the handpiece to expose three differing lengths of
`vemal b~ood pressure of th~ patient 19 es~bhshed a~ the
`the needle in which position 1 constitutes an optimum
`length for an interligamentary injection, position 2 a
`needle ~p to reve!8C the flmd flow back mto the synnge
`where 1t c;3-11 ~ "'.1ewed b~ the operator for the presence 15 maxillary injection and position 3 a mandibular injec-
`tion. If desired indicia 12b can be formed on the hand-
`of ?lood m~1cating a vem or artery has ~~n entered
`piece 12 to indicate the three different positions in
`which ~eqwres that ~e . needle be repo~itioned. As
`shown m FIG. 3, the timmg for the negative pressure
`which the needle is stabilized to different degrees by the
`phase can be on the_or~er of2 t~ 5 seconds. The actual
`pierceable membrane.
`reverse flow or aspiration of flwd represen!s ~e small 20
`Referring to FIG. 5 there is illustrated pumping appa-
`total volume ne7ded to fill the nee~le and VIewmg_ are_a
`ratus for receiving the vial portion 16 of the assembly of
`beyond. The high speed_ expressmn of anesthetic, if
`FIG. 4 at a point remote from the patient but reachable
`needed, can be for a duration of2 to 20 seconds depend-
`b
`th fl
`'bl
`t b'
`15 Th
`I t·
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`h
`f h .. · A
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`d'b 1
`Y e
`eXI e u mg
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`e p as 1c pro ec ive con-
`'al l6 ·
`mg on t e nature o t e 1DJect10n. man i u ar IDJec-
`t •
`th
`l
`t d ·
`· ld bl
`17 ti
`ID a Y_1e a e
`tion at the ascending ram.us of the lower jaw, for exam- 25 amer_
`or e g ass VI_
`is_moun e
`ple, usually requires a full 2 cc. injection in a site deep
`c?uphn~ 18 so _that the nb 19 s~ures the contamer and
`within the lower jaw and takes the maximum time. The
`vial agamst axial move~e~t with respect to a support
`20. The support _20, which is part of a motor and_ motor
`elapsed time of course varies with the rate of flow the
`upper limit of which is determined by the ability of the
`controller ~ousmg (not shown)! has an openmg 21
`site to absorb the anesthetic liquid without creating 30 through "'.'hich passes a tubular p1~ton rod ~2, t?e outer
`end of V.:hich engages the rubber ~1ston 16a ID vial 16. A
`such a large volume of unabsorbed liquid at the needle
`tip that tissue is tom from the bone.
`barbed tip 22a on the end of the piston enters the rubber
`Referring to FIGS. 2A and 2B, in which like parts are
`piston to . en~ble . the piston to be ~ithdrawn _sli~htly
`identified by like reference characters, there is illus-
`when aspiration 1s c~led for: The pISton rod 1s mter-
`trated an injection known as interligamentary, a nor- 35 nally t~eaded to receive a dnve s~rew 23 coupled_to a
`mally difficult and painful injection in which anesthetic
`r~versible stepper ~otor 24. The piston rod 22 1s _axially
`is forced under high pressure through the ligament
`shdably mounted m the support wall 20 and 1s con-
`space llb between the bone and the roots of the tooth to
`str~ed a~ainst rotation by a key 20a on th~ ~upp?rt a~d
`the nerve N which enters the tooth at the root tip. The
`received ID a slot '?r k~y-way 22b so that 1t 1s dnven m
`injection site is prepared by an intermediate injection 40 and out up~n act1vat10~ of the stepp7r ~otor 24 to
`using the low continuous flow rate of between 0.25 and
`pump or asprrate dependmg upon the direction of rota-
`I cc. per minute as the needle is inserted and thereafter
`tion of the drive screw. .
`.
`The stepper ~otor 241s oper~ted_by a dnver 25 con-
`against the bone for a total of8 to 20 seconds (FIG. 2A)
`trolled ?Y ~ micro controller c1rcmt ~6 coupled to an
`to achieve preliniinary numbing. The needle is then
`placed as shown in FIG. 2B and a brief high speed 45 ROM circwt 27 progr~ed ~o ~omtor the pulses to
`the stepper motor to establish 1Im1t stops for piston rod
`injection rate of 2 to 4 cc. per minute is established to
`drive the anesthetic to the nerve N via the periodontal
`positions in and out. The circuit is also programmed to
`ligament space llb. This enables the dentist to anesthe-
`initiate an aspiration cycle, i.e., a small reverse motion
`tize an individual tooth for treatment with a minimum
`for the piston 16a before every "fast" flow rate cycle.
`amount of anesthetic. The apparatus described below so The fast, slow and reverse motions of the piston are
`provides the flow rate and pressure necessary to
`controlled by the operator for slow, fast and reverse by
`achieve this injection method.
`means of switches 28 preferably foot-controlled or a
`Referring to FIG. 4, there is illustrated an assembly of
`combination of foot and manual control. The fast flow
`expendable parts comprising a sterile kit for one injec-
`rate is geared to express liquid anesthetic from the nee-
`tion of anesthetic and used in conjunction with appara- 55 die tip at a rate of between 2 and 4 cc. per minute and
`tus disclosed in FIGS. 5 and 6. The kit includes a handle
`the slow· flow at 0.25 to 1.0 cc. per minute. The aspira-
`or handpiece 12 carrying at one end a hollow hypoder-
`tion cycle is set to achieve in the form of reverse motion
`mic needle 13, preferably in range of 22 to 30 gauge,
`of the piston on the order of 1 to 2 mm. (or at least
`within a retractable transparent sheath 14 and con-
`sufficient to draw back into the needle and the viewing
`nected at the other end to a length of flexible tubing 15. 60 portion of the handpiece viewable liquid drawn back
`The handpiece 12 can be made of transparent plastic
`from the tip of the needle to assure the operator that the
`with a central bore 12a and is preferably in the range 8
`needle has not been threaded into an artery or vein. This
`to 18 centimeters in length and 20 to 50 millimeters in
`test must be done before the high rate of expression of
`circumference.
`anesthetic is commenced, whether it be immediately
`The distal end of the tubing is connected to an anes- 65 after the placement of needle in its flDal position or·
`thetic vial 16 which can be of conventional design
`immediately before the high rate of expression is
`started. It must be gentle to avoid drawing the vein or
`formed of glass and containing a movable rubber piston
`16a to seal in its 2 cc. anesthetic charge. The vial is
`artery wall against the opening in the needle.
`
`Sanofi Exhibit 2170.007
`Mylan v. Sanofi
`IPR2018-01676
`
`

`

`4,747,824
`
`7
`The micro controller circuit includes manual push
`switches 29 and 30 for respectively, manually effecting
`rapid reverse of the piston rod for reloading and rapid
`forward for purging the system of air. An enunciator
`circuit for emitting a small audible tone upon the ejec(cid:173)
`tion of each, say, 0.5 cc. of anesthetic (measured by
`clocking the corresponding number of rotations of the
`shaft 23) provides a means of monitoring the injection
`without requiring the operator to look away from the
`site.
`It will be understood that the apparatus of FIG. Sis
`diagrammatic and can take various forms and arrange(cid:173)
`ments. Reduction gearing can be provided between the
`motor 24 and shaft 23 if required to maintain constant
`discharge pressures which are particularly essential for
`the interligamentary injection requiring high pressure as
`well as a substantial flow rate to drive the anesthetic
`through the tooth ligament to the nerve at the root tip.
`Also, the threaded shaft 23 can be mounted to drive a
`threaded block follower carrying the piston rod in a 20
`laterally offset position relative to the threaded shaft
`and carried in its independent slide bearings.
`In the arrangement of FIG. 6 the anesthetic vial and
`reservoir 40 is incorporated in the handpiece 41 to(cid:173)
`gether with a piston 42 and a coupling rib 43 adapted to 25
`be coupled to a drive rod head 44. A sheathed flexible
`drive rod 45 enters the head 44 and couples through a
`barbed tip 45a to the piston 42. The other end of the
`sheathed drive rod is connected to a motor housing 46,
`with the sheath being secured to the housing and the 30
`flexible push-pull drive rod being secured to a recipro(cid:173)
`catable drive shaft 47 corresponding to the drive shaft
`34 of FIG. 5. The switch controls and motor can also
`correspond to those of the system of FIG. 5.
`While the invention has been described having refer- 35
`ence to preferred embodiments it will be understood
`that it can take other forms and arrangements. For ex(cid:173)
`ample, the controls for the motive means can take the
`
`8
`form of low voltage electrical switches in the hand(cid:173)
`piece. In general, it is preferred that the handpiece be
`made light to afford the operator maximum tactile sen(cid:173)
`sation for needle placement and to free the fingers for
`5 stabilization of the needle. Also, other means for driving
`the piston in the handpiece in the embodiment of FIG.
`5 can be used such for example as a remote hydraulic
`pump connected by a hydraulic line to the back side of
`the piston. In such a system a double piston spaced by a
`10 spreader can be used to prevent leakage contamination.
`The invention should not therefore be regarded as lim(cid:173)
`ited except as defined in the following claims.
`I claim:
`1. A method for anesthetizing body tissue by means of
`15 local anesthetic using a hollow hypodermic needle, the
`steps of
`establishing a uniform flow of anesthetic at a flow
`rate less than 1.0 cc. per minute through the needle
`no later than the instant of entry into the tissue
`maintaining said uniform flow while moving•the nee(cid:173)
`dle into the tissue, whereby said flow rate is suffi(cid:173)
`cient to establish and maintain a sheath of liquid
`anesthetic around the forward portion of the mov(cid:173)
`ing needle thereby to anesthetize the path of travel
`of the needle.
`2. The method of claim 1 including the steps of
`maintaining the flow rate beneath that which would
`displace and tear tissue
`and continuing the liquid discharge after the needle is
`fully implanted to form an anesthetic absorption
`plume around the needle tip tu numb a localized
`space for further treatment.
`3. The method of claim 2 including the step of there(cid:173)
`after increasing the rate of expression of liquid to drive
`the liquid to nerve sites within the localized numb area.
`4. The method of claim 3 in which the increased flow
`rate is between 2 and 4 cc. per minute.
`• * • * *
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`Sanofi Exhibit 2170.008
`Mylan v. Sanofi
`IPR2018-01676
`
`