Devices for injection and dosing

Injection devices are provided which include a handpiece capable of housing a cartridge containing an injectable composition, and a head coupled to the handpiece and housing a plurality of retractable needles and a dosing mechanism. Methods of treating skin surfaces are also provided.

The present invention generally relates to mechanisms for injection and dosing, and more specifically relates to devices for providing minute doses of dermal filler composition superficially into skin.

BACKGROUND

Aesthetic dermal filler procedures have become increasing popular in recent years, as they have proven to be quite effective in improving the appearance of the face, for example, in reducing the signs of aging by smoothing wrinkles and folds, such as the nasolabial folds, and plumping the midface. Some of the more popular dermal fillers are soft, colorless gel compositions made of hyaluronic acid. Hyaluronic acid (HA) is a long chain polymer, more specifically, a polysaccharide, which occurs naturally in body tissues. When chemically crosslinked, hyaluronic acid makes an excellent, long lasting, dermal filler material. Dermal filler procedures are quite minimally invasive, and the results are nearly immediate. Further, hyaluronic acid naturally degrades in the body tissues, and thus the fillers are temporary, for example, lasting several months to a year or more. Further, results of hyaluronic acid based dermal filler procedures can be reversed using hyaluronidase.

Conventional dermal filler procedures are generally performed by injection of the composition into or below the skin using a standard syringe and a fine gauge needle. A typical dermal filler patient may undergo from about 5 to about 10 injections in a single procedure, with injection points across various regions of the face. While the goal may be to improve the appearance of the entire face, a skilled aesthetic physician generally aims to correct one or more specific regions of the face, for example, regions that lack volume such as the lips or the cheeks, or regions that present specific wrinkles, such as deep nasolabial folds, with specific input from the patient regarding areas he or she finds detracting to his or her appearance.

It has been discovered that improvement of facial appearance can also be accomplished by introducing minute amounts of compositions into skin at a very superficial depth, and across wide regions of the skin, rather than focusing on specific wrinkles or specific areas of the face that lack volume.

SUMMARY

The present invention is generally directed to a device that can be used to deliver a composition into skin, for example, in a way that is effective to treat or improve the skin surface. The device is structured for treating or improving skin by delivering a composition, for example a gel, for example, a dermal filler gel, into skin, at a relatively shallow depth, to improve the appearance of the skin, and perhaps improve overall skin health and quality. The device advantageously facilitates treatment of a large surface area of skin, such as the entire face, neck and/or décolletage, or significant regions thereof. The device allows for controlled depth of injection, especially for superficial intradermal delivery of compositions, for example, dermal filler gels or other compositions effective to enhance the health or appearance of skin. The injection may be between about 0.5 mm about 3 mm for intradermal injection, or deeper for subdermal injection.

For example, the device is more efficient at delivering doses of a hyaluronic acid based dermal filler to a large surface area of skin than is currently possible with a standard needle and syringe.

In some embodiments, a dermal filler injection device is provided which generally comprises a handpiece including a housing having an interior space for containing a cartridge and a trigger coupled to the housing. The device further includes a head in communication with the interior space. In some embodiments, the head is removable with respect to the handpiece. In some embodiments, the device includes at least one retractable needle and at least one dosing chamber coupled thereto. Operation of the trigger causes the needle to be moved from a retracted position to an extended position and a dose of a composition to be delivered from the needle tip.

In some embodiments, the at least one needle comprises a plurality of needles, with each one of the needles coupled to a corresponding one of the dosing chambers. In this embodiment, the device may be structured such that operation of the trigger initially causes the plurality of needles to be moved from a retracted position to an extended position and subsequently causes a dose of fluid contained in the corresponding dosing chambers to be ejected from the needles, for example, substantially simultaneously, when the needles are in the extended position. The device may be further structured to cause retraction of the needles after the dosing. In some embodiments the device includes a mechanism capable of filling each dosing chamber between subsequent injections.

The plurality of needles may comprise linearly arranged needles, for example, at least three, for example, about four, or more linearly arranged needles. In some embodiments, the needles are arranged in an array. For example, the needles may be arranged in a two by two array, a two by three array, a four by four array, a six by six array, a two by four array, or any other suitable configuration.

In one embodiment, the head of the device may include a plurality of conical or tapered projections, each needle having a tip protruding from an individual conical or tapered projection. For example, each conical or tapered projection is spaced apart from each other conical or tapered projections so as to effect a preloading of skin when the head is applied to skin, to facilitate penetration of the needle tips into the skin.

In one aspect, a method for treating skin is provided, wherein the method generally comprises placing a distal end of a handheld device into direct contact with skin to be treated; causing the device to inject a dose of a composition into the skin through a plurality of needles, substantially simultaneously; moving the distal end of the device onto another portion of the skin while maintaining the direct contact with the skin; and, after the step of moving, causing the device to inject another dose of the composition into another portion of the skin. In another aspect of the invention, the needles are in a retracted position during the moving step. The needles are in an extended position during the dosing or delivery of the composition into the skin.

DETAILED DESCRIPTION

A device10in accordance with an exemplary embodiment of the invention is shown inFIG. 1. Device10is configured and shaped to be held and operated by a single hand of a user, for example an aesthetic physician. Device may be used to deliver micro-depot injections of composition into skin, with the aim of improving the appearance of skin, for example, reducing the appearance of fine lines or superficial skin depressions, thereby improving skin texture. Depending on the composition being delivered, device10may also be effective for use in improving or increasing skin elasticity and hydration.

Device10generally comprises a handpiece12, and a head14coupled thereto. The handpiece12includes a main housing18, and a trigger16coupled to the main housing18.

As shown inFIGS. 2-4, device10is shown in the several operational stages that occur during operation of the device10when used to deliver multiple, shallow, doses of a composition19into skin.

Turning now toFIG. 2, the device10is shown, in cross-sectional view, in a neutral position, for example, a position of which the device10is not yet actuated, and is ready to be used to introduce the composition19, for example, a dermal filler, for example, a crosslinked and/or uncrosslinked hyaluronic acid-based dermal filler, or other beneficial composition.

When the device10is in the neutral position, needles22of the device10are positioned in a retracted position within the head14. At this stage, handpiece12is comfortably grasped by the user, and is placed into contact with a region of a patient's skin (not shown) to be treated, with the head14of the device10touching the skin.

FIG. 3shows the device10during an initial stage of the trigger16being manually pressed, for example by a thumb or index finger of the user, in which the needles22are caused to be moved to an extended position. As the needles22extend, they are caused to puncture the surface of the skin in contact with the head14.

Turning toFIG. 4, as the user continues to press trigger16, multiple small, shallow doses2, aliquots, or micro depots of the composition, are delivered from the extended needles22and into the skin.

Needles may be spaced apart from one another any suitable distance. In the embodiment shown, adjacent needles are spaced apart about 10 mm. In other embodiments, the spacing between adjacent needles may be, for example, less than 10 mm, for example, about 3 mm, about 5 mm, about 7 mm. In yet other embodiments, the needles are spaced apart more than 10 mm, for example, about 12 mm, about 14 mm, about 16 mm, or about 20 mm, or more. In yet other embodiments, spacing between adjacent needles is about 1 mm to about 20 mm, for example, about 3 mm to about 14 mm, for example, about 5 mm to about 12 mm, for example, about 7 mm to about 10 mm.

As illustrated inFIG. 5, as the user initially releases pressure on the trigger16, the needles22remain for a moment in the extended position, while the dosing of composition from the device10is stopped.FIG. 6shows that upon completion of the release of the trigger16, the needles22have moved back into the retracted position, and the device10once again in the neutral position, is ready to be actuated for the next dose.

The operational mechanism of device10may be more clearly understood with reference to the magnified views ofFIGS. 7-11.

Turning now toFIG. 7, head14comprises a needle array housing assembly32, and a needle hub34disposed within the needle array housing assembly32. A plurality of needles22, for example, four needles22, are secured in the needle hub34. A needle assembly spring38is seated between the needle array housing assembly32and the needle hub34.

Needles22may be arranged linearly, as shown, for example, arranged in a single row of three or more, for example, four to about 20 or more, needles. The exemplary embodiment shown comprises a 1×4 needle array. Alternative devices of the invention including different needle array arrangements include other devices having other arrays, such as, for example but certainly not limited to, a 1×3 array, a 3×3 array, a 2×3 array, or a 4×4 needle array212, such as device210shown inFIG. 17. Any other suitable needle array (e.g. a×b, wherein a is at least one and up to 20, or more, and b is at least one and up to 20, or more), may be provided within the scope of the invention.

Needle array housing assembly32comprises a needle portion42having distal projecting regions44, for example, four projecting regions44, each distal projecting region44having an aperture46for receiving one of the needles22, and a recess47. Needle array housing assembly32further comprises a contact portion48having a distal surface52generally circumscribing the distal projecting regions44. Needle array housing assembly32further comprises a base portion54, which may abut against main housing18of handpiece12.

In some embodiments, the device10is structured to facilitate injection. For example, the projecting regions44are in the form of conical or tapered projections, as shown, with each needle22protruding from an individual conical or tapered projection44. In some embodiments, each conical or tapered projection44is spaced apart from each other conical or tapered projections so as to effect a preloading of skin when the head14is applied to skin during treatment. By preloading of the skin, the conical or tapered portions44facilitate penetration of the needle tips into the skin.

Needle hub34comprises a first portion56and a second portion58rigidly secured together and holding the needles22. First portion56includes hub projecting regions59, for example, four hub projecting regions59. Each hub projecting region59is aligned with a recess47of a corresponding distal projecting region44of the needle array housing assembly32, as shown.

Briefly turning back toFIG. 2, the handpiece12includes an internal assembly70, which, upon manual activation of trigger16, is urged forward, i.e. distally, within the handpiece main housing18, to cause dispensing of an accurate, shallow dose of the composition19into skin by way of the needles22, as will be described in greater detail hereinafter.

Referring back toFIG. 7, internal assembly70generally comprises a distribution manifold72, a dosing manifold74, a dosing block76, a dosing spring77, and a one-way mechanism78(see brieflyFIG. 5orFIG. 16). Distribution manifold72and dosing manifold74are rigidly connected together and sealed. Referring briefly toFIG. 12, dosing manifold74includes individual plungers79which correlate with individual dosing chambers80in the dosing block76. Although they are not all visible in the Drawings, in this exemplary embodiment, there are four dosing chambers80and four corresponding dosing plungers79, since the shown embodiment includes four needles22.

Although the exemplary device10is a four needle embodiment, it should readily be appreciated that other embodiments of the device not shown may include any number of needles, for example, less than four, for example, two or three, or more than four, for example, five, ten, twenty or more, wherein the device is structured such that each needle has a corresponding dosing chamber and individual plunger, with the required modifications to the components of the invention, and all these embodiments are considered to fall within the scope of the invention.

As shown most clearly perhaps inFIG. 2, the handpiece12includes an interior space, for example, defined by the handpiece main housing18, for receiving a cartridge assembly82. The device10is structured such that the cartridge assembly82is removable from the handpiece main housing18and replaceable. Cartridge assembly82comprises a cartridge84containing the composition19to be injected, and a cartridge plunger86slidable within the cartridge84and including plunger head88in contact with composition19. Cartridge82includes cartridge distal portion92.

As shown inFIG. 5, the one-way mechanism78may be in the form of any mechanical structure that allows cartridge plunger86to move only in the distal direction during operation of the device10. For example, one-way mechanism78may be in the form of elements78a, such as leaves, for example, rigid or flexible leaves, that taper inwardly against and/or otherwise engage the cartridge plunger86and prevent the linear motion of that cartridge plunger86in one of two directions, for example, prevent the movement of the plunger86in a reverse or proximal direction, while enabling the plunger86to move in a forward, or distal direction. Alternative mechanisms are also contemplated and considered to be within the scope of the invention. For example, the one-way mechanism may be in the form of gears78band teeth78con plunger, such as shown in simplified view inFIG. 5A, such that the cartridge plunger86can move forwardly, but not backward.

Referring back toFIG. 7, distribution manifold72includes flange structure94which is mateable with cartridge distal portion92. Forward (distal) motion of the cartridge plunger86pushes composition contained in the cartridge84forward and toward distribution manifold where it is distributed among the dosing chambers80, and eventually ejected from the needles22.

The dosing chambers80may each be sized to contain a drop or an aliquot of composition to be injected. By way of example only, the dosing chamber80may be sized or structured to contain at least 2 μl and up to about 100 μl or 200 μl or greater of a composition. For example, in some embodiments, the dosing chamber80is sized and/or structured to contain between about 2 μl and about 100 μl of a composition, for example, between about 5 μl and about 50 μl, for example, between about 10 μl and about 40 μl of composition per dosing chamber80. In some embodiments, each dosing chamber80is sized and/or structured to contain, for example, about 20 μl, about 40 μl, about 60 μl, about 80 μl, about 100 μl, or more of a composition.

Briefly referring toFIG. 16, cartridge assembly82may be removable from the handpiece12, and replaceable. As shown, main housing18includes pivotable portion98. Pivotable portion98may encompass the trigger16. To replace the cartridge assembly82, cartridge distal portion92snaps into flange structure94of distribution manifold72, as well as retaining clips95of the distribution manifold72, and cartridge plunger86is coupled to one-way mechanism78. Once the cartridge assembly82is loaded into the handpiece12, pivotable portion98is pivoted closed and the device10is in the neutral position (FIGS. 2 and 7) and is ready to use. In alternative embodiments, the cartridge assembly is refillable, but not readily removable by a user of the device.

Turning toFIG. 8, the user begins to press the trigger16in the direction indicated by arrow99.

As the trigger16moves, a cam surface96on an internal portion of the trigger16presses on rollers106(seeFIG. 12) which are attached to the distribution manifold72. This action moves the distribution manifold72, dosing manifold74, dosing block76, and one-way mechanism (not shown inFIG. 8), cartridge84, cartridge plunger (not shown inFIG. 8), and needle hub34forward, compressing needle assembly spring38. This causes the needles22to be extended relative to portion42of needle array housing assembly32, and past the distal surface52. In the shown embodiment, the needles extend approximately 0.5 mm to about 2.0 mm, or more specifically, about 1.5 mm. It can be appreciated that the needles may extend a distance less than 0.5 mm or greater than 2.0 mm, in accordance with different embodiments of the invention.

Once the needle hub34has fully compressed the needle assembly spring38, and has reached the limit of its travel, the needle hub34and dosing block76and one way mechanism stop moving, and the dosing spring77begins to compress. As shown inFIG. 9, as the dosing spring77compresses, the distribution manifold72, dosing manifold74, cartridge84and cartridge plunger (not visible inFIG. 9) continue to move forward (distally).

Turning briefly back toFIG. 12, the individual plungers79of the dosing manifold74deliver small doses2of the composition19through the needles22by compressing the dosing chambers80defined in the dosing block76, which is not moving with respect to the housing18. (Prior to this stage, the dosing block76was slidable with respect to the housing18). Check valves108, closed during dosing, may be provided to prevent composition19from flowing back into the cartridge84. When the trigger16is fully compressed (FIGS. 4, 9 and 12), the dose is fully delivered.

The present invention may further include a mechanism capable of filling each dosing chamber between subsequent injections. For example, turning toFIGS. 5 and 10, when the trigger16is released, the dosing spring77is the first to expand, which pushes the distribution manifold72/dosing manifold74and cartridge84back (proximally), but the cartridge plunger86gets trapped in one-way mechanism78and cannot move back with the cartridge84. The cartridge84moving back over the stationary cartridge plunger86causes liquid to flow from the cartridge84through the distribution manifold72/dosing manifold74going through the check valves108(not visible inFIG. 10). In some embodiments, the needle diameter is small relative to other flow paths and acts as a shut off valve during the filling of the dosing chambers. so the injectable composition does not leak out the needles. Once full, the dosing spring77can no longer expand the assembly and now the whole internal assembly starts to move back under the force of the needle assembly spring38. This retracts the needles22back into the device10(seeFIG. 11) and it is now ready for another cycle.

Advantageously, in some embodiments, head14, or at least the needle portion thereof, is detachable and replaceable from the handpiece12. This feature is shown inFIGS. 13-14. In use, head14may be replaced at the same time cartridge (not shown inFIGS. 14-16) is replaced, for example, after a certain number of injections, thus providing new, sharp needles for each subsequent use. For example, head14is detachable from handpiece12, and can be replaced with another head, for example, an identical head, by rotating head14with respect to handpiece12. This may be accomplished in a number of ways, for example, the device10may be structured such that replacing head14comprises the steps of manually placing head14onto handpiece12at 90° out of alignment therewith, and subsequently twisting or rotating head14clockwise 90° into alignment to lock it in place on handpiece12. Removing head14may be accomplished, for example, by performing the steps in reverse.

In the shown embodiment, head14is separable from a distal hub112portion of handpiece12which houses dosing block, dosing spring, and dosing manifold. Thus, in this particular example, head14, including the needle array housing assembly32, needles22, needle hub and needle assembly spring, as described and shown elsewhere herein, is replaceable with respect to the handpiece12. In alternative embodiments, replaceable components may include one or more components or portions of the dosing manifold or distribution manifold. Needles22may be in a retracted position when the head14is separated from handpiece12. Distal hub112may include coupling threads114or other suitable structure, for engaging mating threads or other structure (not shown) within head14.

Methods of using device10for treatment or improvement of skin are also provided. For example, a method comprises providing a device such as described and shown herein.

A user, for example, a physician or an aesthetician, selects a region of skin to be treated on a patient. Potential skin regions that may benefit by treatment with device include the entire face, or portions thereof, including the forehead, the cheek, the nose, and the chin, the neck, the décolletage, the shoulders, the back, and any other region of skin that would benefit from improved hydration, elasticity, improved texture, and reduced fine lines and depressions.

The head of the device is placed into contact with a boundary of the selected area of skin to be treated. The user activates the device, for example, by pressing trigger. While the device remains in contact with the skin, one aliquot of composition is delivered into the area, simultaneously from each of the needles, at spaced apart injection points. Thus, when using the exemplary device shown and described, four aliquots or doses of composition are delivered simultaneously into the skin at about 10 mm apart, at a depth of about 0.5 mm to about 3.0 mm, for example, about 1 mm. While the device is still positioned against the skin, the user releases the trigger and the needles are retracted from the skin. Once the needles have retracted, the user moves the device laterally to an adjacent region of the skin, and the user again activates the device, delivering another set of doses.

Interestingly, the structure of the present device allows the user to maintain the device in contact with the skin during the treatment and between trigger presses. Because the needles retract into the head and behind the distal-most region of the head (such as shown inFIGS. 2 and 6) instead of lifting the device between subsequently delivered doses, the user may safely slide the device head on the skin to the next portion of skin in the treatment region before pressing the trigger to deliver the next set of doses.

The device may be structured to reduce or mitigate pain or anxiety in the patient. As mentioned above, the structure of the present invention, for example, when used as described, provides squeeze/slide action over the face or other treatment region. This feature may improve the comfort of the patient's experience, for example, in that the patient is not subjected to repeated lifting and contact of the device head on her skin, which may be relatively unpleasant to the patient and cumbersome to the physician. For example, when being treated with the present device, the patient may experience the treatment as a continuous, rather smooth, uninterrupted process, even between trigger presses, as the device maintains contact with the skin rather than the device needing to be repeatedly lifted and reapplied. Furthermore, the structure of the device provides an additional advantage in that it enables doses to be delivered without need to press the needles, or even the device head, into the skin. The doses are delivered by rapid trigger action as described herein, while the device is in gentle contact with the skin. Advantageously, the conical portions44described elsewhere herein may also provide some pain relief to the patient, by preloading or stretching the skin immediately prior to the injection, thereby possibly reducing or mitigating pain caused by the needle prick. In a similar respect, it is also contemplated to be within the scope of the invention to provide a vibrating motor on the device, effective to cause the head to vibrate when applied to the skin, thereby also mitigating pain of injection.

In some embodiments, the dose delivered from the sum of the needles, that is, from the plurality of needles in sum, e.g. during a single trigger pull, is for example about 1 ml, or about 2 ml, or about 3 ml, or about 4 ml or about 5 ml. In some embodiments, the dose delivered from the sum of the needles, is between about 10 μl to about 2 ml. In some embodiments, the dose delivered from the sum of the needles is between about 20 μl and about 1 ml. In some embodiments, the dose delivered from the sum of the needles is about 10 μl, about 20 μl, about 30 μl, about 40 μl, about 50 μl, about 60 μl, about 70 μl, about 80 μl, about 90 μl, about 100 μl, about 120 μL about 140 μL, about 160 μL, about 180 μL, about 200 μL, about 300 μL about 400 μL, or about 500 μL, or greater.

Again, by way of example only, in some embodiments, the dose delivered per needle of the plurality of needles, e.g. during a single trigger pull, is between about 2 μl and about 100 μl, between about 2 μL to about 200 μl, or between about 2 and about 300 μL. In some embodiments, the dose delivered per needle per trigger pull is, for example, between about 5 μL to about 100 μL, from about 10 μL to about 80 μL, or from about 40 μL to about 60 μL. In some embodiments, the dose delivered per needle per trigger pull is between about 5 μl and about 50 μl, for example, between about 10 μl and about 40 μl per needle. In some embodiments, the device is capable of providing doses from each needle tip in an amount of about 6 μl, about 8 μl, about 10 μl, about 12 μl, about 14 μl, about 16 μl, about 18 μl, about 20 μl, about 22 μl, or about 24 μl, or greater. For example, in some embodiments, the device is capable of providing doses from each needle tip of about 30 μL, about 40 μL, about 50 μL, about 60 μL, about 70 μL, about 80 μL, about 90 μL, about 100 μL, or greater. In some embodiments, the dose delivered per needle per trigger pull is less than about 200 μL, less than about 100 μL, less than about 50 μL, less than about 25 μL, less than about 10 μL, or less than about 5 μL.

In one embodiment (e.g. a four needle embodiment), the device is structured to be capable of delivering 40 μL of composition, per trigger pull, by way of 4 spaced-apart, simultaneously injections of 10 μL. In another embodiment, (e.g. a ten needle embodiment), the device is capable of delivering 100 μL of composition, per trigger pull, by way of 10 spaced-apart, simultaneously injections of 10 μL. In another embodiment, (e.g. an eight needle embodiment), the device is capable of delivering 40 μL of composition, per trigger pull, by way of eight spaced-apart, simultaneously injections of 5 μL. In yet another embodiment (e.g. another ten needle embodiment), the device is capable of delivering 200 μL of composition, per trigger pull, by way of 10 spaced-apart, simultaneously injections of 20 μL. In yet a still further another embodiment (e.g. another ten needle embodiment), the device is capable of delivering 20 μL of composition, per trigger pull, by way of 10 spaced-apart, simultaneously injections of 2 μL. In still another embodiment (e.g. a 20 needle embodiment), the device is capable of delivering 400 μL of composition, per trigger pull, by way of 20 spaced-apart, simultaneously injections of 20 μL. In another embodiment (e.g. a two needle embodiment), the device is capable of delivering 200 μL of composition, per trigger pull, by way of 2 spaced-apart, simultaneously injections of 100 μL. These are some examples of various embodiments of the invention, and are not intended to limit the scope of the invention.

In yet other embodiments, the device enables treatment of a skin surface in a reduced amount of time, relative to conventional devices and techniques, for example, relative to treatment of a region of the same size using a standard needle and syringe. For example, in some embodiments, the device is capable of delivering about 1 ml to about 2 ml of a fluid into skin in depots of 5 μL to about 100 μL, for example, in a time of about 45 minutes, about 30 minutes, about 20 minutes, about 15 minutes, or about 10 minutes.

The device may be structured such that a desired depth of injection is achieved, for example, to achieve a target depth in the epidermis, dermis or the hypodermis. It will be appreciated that the desired depth of injection may be at least somewhat dependent on the area of skin being treated, and/or the desired aesthetic or therapeutic effect to be achieved.

Embodiments of the invention include needle lengths, for example, lengths of between about 2 mm to about 20 mm, for example, a needle having a length of about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, or about 20 mm, or other length suitable for delivering composition at a desired depth. In some embodiments, the needle gauge is 18 G, 22 G, 25 G, 27 G, or 30 G or thinner. In some embodiments, the needle gauge is at least 27 G up to about 34 G, for example, 30 G, 32 G, 33 G, or 34 G.

By way of example, the device may be structured to achieve treatment of skin by injection of composition at a very shallow level, for example, at a depth of about 0.1 mm or about 0.5 mm to about 2 mm or about 3 mm, into the epidermis. In other embodiments, deeper injection into the skin may be achieved. For example, in some embodiments, the depth of injection is between about 2 mm to about 4 mm. Even deeper injections may be between about 4 mm to about 10 mm, or even about 12 mm to about 15 mm in depth. In some embodiments, the depth of injection is about 0.5 mm to about 2 mm. In other embodiments, the depth of injection is about 4 mm to about 10 mm. In other embodiments, the depth of injection, is about 5 mm to about 12 mm.

Methods for using the device may include the step of moving the device along the skin between doses so as to effect subsequent, spaced apart doses so as to treat a desired surface area of skin with spaced apart injections. In some embodiments, the method includes delivering subsequent doses (each dose including delivery of composition from the plurality of needles) at spaced apart regions of the skin. For example, in some embodiments, the doses are spaced apart by about 5 mm and about 20 mm, for example, wherein the doses are spaced apart by about 10 mm, or about 15 mm. By thus moving the device along the skin between trigger pulls, a large surface area of skin can be treated by closely spaced apart injections.

EXAMPLE

For the sake of simplicity, the following example, refers to a four-needle device, for example, device10, but it should be appreciated that a similar sequence of steps can be used, mutatis mutandis, with other embodiments of the invention, which include, for example, different numbers and/or arrangements of needles.

A 43-year old woman complains to her dermatologist that she is dissatisfied with the appearance of her face, and more specifically, her skin. The dermatologist observes that the woman's facial skin, while having relatively few wrinkles and lines that are common to women her age, appears dry and blotchy, and the texture irregular, with highly visible pores and old acne scars in the form of shallow depressions.

The physician explains to the woman that a traditional dermal filler treatment would be helpful to fill in the few, and mostly insignificant, wrinkles, but that such traditional dermal filler treatment would not necessarily provide what she is looking for, that is, an improvement in the overall appearance of her skin, e.g. restoration of a youthful glow, decreased dryness, and improvement in texture and smoothness. The dermatologist recommends a microinjection treatment using a device (e.g. device10) as described herein, to introduce, through multiple shallow injections, a hyaluronic-based composition, which may contain vitamins, antioxidants and/or other beneficial ingredients. The patient agrees to undergo the treatment.

Beginning near the jawline of the patient, the dermatologist gently places the distal end of the device on the skin. Without pressing the device into the skin, e.g. any more than is necessary to simply maintain gentle contact therewith, the physician presses the trigger. Four doses of composition are simultaneously delivered from the needles shallowly into the skin. Each needle delivers a single drop of the composition, for example, about 10 μl. A single trigger squeeze delivers therefor about 40 μl of the composition (4×10 μl) into a region of skin about 40 mm in length. The depth of the injection is between about 0.5 mm and about 3 mm. The needles automatically retract. While retaining contact with the skin, the dermatologist slides the device laterally along the face, a distance of only about 5 to about 10 mm, and again presses the trigger. A second injection is administered, e.g. another 40 μl provided through the four needles. The dermatologist repeats the slide and trigger action until the region of skin has been treated with multiple, shallow injections of small drops of the composition. After 25 trigger pulls, or in other words, 25 deliveries of 40 μl doses (4×10 μl), about 1 ml of composition has been delivered to the skin (40 μl×25=1 ml).

The physician next ejects the spent cartridge from the device, and replaces it with a new full 1.0 ml cartridge (seeFIG. 16). The dermatologist also removes and replaces original, spent head with a new, unused head14(seeFIG. 13-15), the new head having brand new, sharp needles (the needles of original head having become dull from the 25 injections). The dermatologist repeats the treatment on the other portion of the patient's face using the new head and a new cartridge. This process is repeated until the full skin area is treated as desired. The procedure is relatively painless and fast, and takes only about 20 to about 45 minutes. The patient is told to wear sunscreen when she is outdoors and to drink plenty of water over the next few days to protect her newly treated skin.

Within several days of treatment, the patient notices a visible improvement of her complexion. Her skin is noticeably suppler and less dry, more hydrated. The minute acne scar depressions are nearly gone, and her pores appear less visible. She returns to the dermatologist for a follow up treatment every 6 weeks, and tells him she is pleased that her face has a more youthful glow.