Abstract:
A method for treating skin by administration of a neurotoxin such as a botulinum toxin by means of a dry needle. The method can be used to accomplish what has generally been described as skin rejuvenation and also to treat skin disorders such as skin lines, crepiness, excess skin, wrinkles, platysmal bands, uneven skin tone and color, and hyperhidrosis.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This application claims the benefit of provisional application 61/293,973 which was filed on Jan. 11, 2010. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a method for treating skin by administration of a neurotoxin such as a botulinum toxin by means of a dry needle. The method can be used to accomplish what has generally been described as skin rejuvenation and also to treat skin disorders such as skin lines, crepiness, excess skin, wrinkles, platysmal bands, uneven skin tone and color, and hyperhidrosis. 
     SUMMARY OF THE INVENTION 
     The method makes use neurotoxins such as the type produced by the bacterium  Clostridium botulinum . Among the serotypes of botulinum neurotoxins that can be used with the method are the serotypes A, B, Cl, D, E, F and G. These serotypes are produced by neutralization with type-specific antibodies and vary in their potency and the respective effects they exert among animal species. For example, botulinum neurotoxin type-A (BoNTA) can have an efficacy for up to 12 months. Other types of neurotoxins may be used with the method as well, including those made by other species of  Clostridium  such as  Clostridium tetani, Clostridium butyricum , and  Clostridium beratti . The Clostridial toxin used in the present method is preferably BoNTA. 
     The method consists of making small punctures into the epidermis and dermis encompassed by an area of treatment and then making a first application of a small amount of neurotoxin solution onto the outer surface of the skin. Additional punctures are then made followed by a second application of neurotoxin solution. The process of making the punctures reddens the skin (i.e., causes mild erythema) and may be generally perceived as irritating to the patient. In the preferred embodiment, the punctures are made using a hypodermic needle. However, other means of making punctures could be used such as using a solid needle, microknife, or microblade. In addition, the punctures can be made using devices on which multiple needles, blades, or acicular protuberances are mounted. The accumulation of punctures will manifest themselves in the form of skin appearance ranging from mild swelling and redness to pinpoint bleeding. Occasionally, a bruise may occur. The punctures allow the neurotoxin solution to permeate through the dermis and exert an effect on the underlying muscles to produce a beneficial treatment. 
     The amount of a neurotoxin selected for administration can be varied based upon criteria such as the severity and nature of the condition being treated, the characteristics of the neurotoxin toxin chosen, as well as the age, sex, body habitus, and health of the patient. For example, the effect of the treatment is generally proportional to the concentration of a neurotoxin in the solution administered. The method allows for precise control over the number, location, and spatial density of the punctures as well as control of the rate at which the punctures are made. The ability to control these factors is advantageous with respect to promoting efficacy of the procedure. Furthermore, the person administering the treatment can monitor the rate of absorption of the neurotoxin solution, evaluate the effect, maintain control of the procedure, and make adjustments accordingly. The two-application procedure has been found to be surprisingly advantageous with respect to the ability to monitor and control the application over single-application procedures. The method further allows the person administering the treatment to visually monitor for patient discomfort and to receive feedback from the patient. Methods for determining the appropriate dosage are generally determined on a case-by-case basis by the attending physician and are either routine to one of ordinary skill in the art or may be determined without an undue degree of experimentation. When the selected neurotoxin is BoNTA, the beneficial effects of the procedure generally last about three months. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1  is a schematic showing the syringe with hypodermic needle and container of neurotoxin. 
         FIG. 2  is a view of a treatment area on the neck of a patient showing the puncture-making process. 
         FIG. 3  is a side view showing the penetration of a hypodermic needle into the dermis. 
         FIG. 4  is a view of a treatment area on the neck of a patient showing the erythema associated with the punctures. 
         FIG. 5  is a side view showing several punctures into the dermis and the overlying film of neurotoxin solution. 
         FIG. 6  is a view of a treatment area on the neck of a patient showing a gloved finger massaging the treatment area to promote absorption of the fluid. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a syringe assembly  10  consisting of a syringe barrel  11 , piston  12 , and hypodermic needle  13 . Also depicted is an injection vial  14  of neurotoxin which has been rendered into a solution  15  by injecting a fluid such as normal saline into the vial. Afterwards, the needle  13  is inserted into the injection vial  14  and the piston  12  is withdrawn so as to fill the barrel  11  with the desired amount of neurotoxin solution  15 . It should be noted that the invention is not dependent on using a syringe  10  of the kind shown in the figures and that any method of applying a neurotoxin solution is acceptable such as swabs, pipettes, or pouring from glassware such as beakers. However, due to the typical packaging of neurotoxin in injection vials, the use of a hypodermic syringe and needle is preferred as this combination expedites the administration of the treatment. The type and volume of the syringe may encompass the kinds commonly used in the medical professions for hypodermic injections but it is preferred that the syringe be of a size that is easily held and controlled by the person administering the treatment and that the syringe have sufficient volume to hold all the neurotoxin solution required during the administration of the treatment. A needle ranging in gauge from 25 to 34 is preferred and ranging in gauge from 29 to 32 even more preferred. 
     Enough neurotoxin solution  15  should be prepared to carry the neurotoxin to the treatment area which it is covers. In addition, the solution should be made with sufficient neurotoxin to effect the treatment. The specific dilutions may vary depending on the particular neurotoxin formulation being administered. 
     Prior to the performance of the procedure, the patient is positioned in a chair in a semirecumbent position and the area of treatment exposed, for example, by removing clothing or jewelry in the vicinity of the area to be treated. Towels may be placed around the area of treatment to isolate the treatment area and prevent hair or fabric from contacting the treatment area during the procedure. The outer surface of the skin in the area of the treatment is cleaned and disinfected by wiping with an antiseptic or disinfectant such as alcohol and allowing the skin to dry. 
       FIG. 2  depicts the procedure being conducted on a treatment area  22  of the neck  21  of a patient  20 . The hypodermic needle  13  is “bounced” across the treatment area  22  in a random but somewhat organized manner to produce serial punctures. As shown in  FIG. 3 , the point  16  of the needle  13  incises through the epidermis  30  into the dermis  31  but not into the hypodermis  32 . Preferably, the punctures  23  are created by pushing downward with the face of the beveled portion of the point  16  oriented so that it is perpendicular to the surface of the skin. Generally, the syringe  11  will be held at a 45-degree angle to the skin and moved in a downward-and-upward motion perpendicular to the surface of the skin. The depth of the punctures  23  created by the needle  13  will vary depending on the thickness of the epidermis and dermis. The epidermis varies in thickness depending on the part of the body. Its thickness can be up to a millimeter or more in areas such as the palms and soles and may be only a tenth of a millimeter over the eyelids but is generally about a half-millimeter over most of the body. The dermis ranges one to four millimeters in thickness being about half a millimeter over the eyelids and several millimeters over portions of the back. In the more commonly areas receiving the treatment, such as the neck, the punctures  23  are made to a depth of less than 1 millimeter and generally less than 0.5 millimeters using a 31 gauge needle  13 . 
     The process of creating punctures is continued until mild erythema  24  is present over the treatment area  22  as shown in  FIG. 4 . In some cases, pinpoint bleeding may occur. At this point, the needle  13  is positioned close to but not touching the skin and the piston  12  of the hypodermic syringe  10  is very slowly depressed to apply small drops of the neurotoxin solution  15  over the area encompassed by the punctures  23  until the treatment area  22  is covered by a thin film of neurotoxin solution  15  as shown in  FIG. 5 . Additional punctures  23  are then made into the treatment area  22  with particular attention paid to the problem areas such as skin lines, crepiness, excess skin, platysmal bands, and uneven skin tone and color. Afterwards, more drops of neurotoxin solution  15  are applied in the manner just described. All the neurotoxin solution  15  is allowed to absorb into treatment and none is blotted. However, a gloved finger  60  may be used to rub the treatment area  22  to facilitate the absorption of the neurotoxin solution  15 . By the end of the procedure, the treatment area will be covered by about five to ten punctures per square centimeter. 
     In the preferred embodiment, about 1 cubic centimeter of BoNTA solution will be applied to a treatment area on the neck having an area of about 100 square centimeters. The solution will typically take about 5 minutes to absorb into the skin after cessation of creating the punctures. It should be noted that the number of punctures per square centimeter to allow absorption of the neurotoxin solution will vary depending on the characteristics of the skin such as thickness and permeability and in some instances a lesser or greater number of punctures may be required than the five to ten typically associated with the treatment of the skin surface over the neck. 
     Following the procedure, the treatment area is kept clean and not wiped or washed for at least two hours. The patient is also instructed not to engage in any activity that might induce appreciable sweating at or near the treatment area such as physical activity and to avoid exposure to heat or sunlight. 
     EXAMPLE 
     Use of a Botulinum Toxin to Treat Rhytids, Skin Laxity, Texture, Tone, and Color Irregularities of the Neck 
     A 50 year-old female patient with an “aging neck” exhibiting rhytids, skin laxity, texture, tone, and color irregularities was treated using the method. An area of about 100 square centimeters was treated by applying small punctures in accordance with the method previously described until the treatment area exhibited pinpoint bleeding, erythema, and edema, About 25 units of BOTOX (onabotulinumtoxin A marketed by Allergan, Inc.), diluted with normal saline was initially applied over the treatment area and gently rubbed until the solution was absorbed by the skin. A subsequent round of punctures were made to the treatment area followed by the application and absorption of the remainder of the BOTOX solution so that a total of 50 units was applied to and absorbed by the skin and hemostasis was achieved. The treatment was repeated two weeks later. Clinically-significant improvement was noted with respect to rhytids, skin laxity, texture, tone, and color irregularities. The patient reported very high satisfaction with the results and no difficulties in swallowing or decrease in neck strength was noted. Positive effects lasted for at least three months based on the observations by the treating physician and subjective reports by the patient. 
     As will be apparent to a person skilled in the art, a number of variations and modifications can be made to the structure described above without departing from the spirit and scope of the present invention.