Microbotox of the Lower Face and Neck: Evolution of a Personal Technique and Its Clinical Effects

Sir: I read with interest the article by Dr. Woffles Wu entitled "Microbotox of the Lower Face and Neck: Evolution of a Personal Technique and Its Clinical Effects."1 He describes his technique of intradermal botulinum toxin treatment. He informs the reader that he described this method as early as 2000, coined the term Microbotox in 2001, and cites several references. His first reference is an unpublished presentation, making it impossible to independently verify that he presented his mesobotox method as early as 2002.2 His other supporting references were published, but the earliest reference dates from 2007, not 2006 as cited in his article.3 In 2005, I independently conceptualized a method of using onabotulinum toxin to rejuvenate the eyebrows and forehead rhytides. I observed that eyebrow position is determined by the balance of muscular activity between the eyebrow elevators and depressors. The brow depressors include the superior orbital orbicularis oculi muscle inserting into the brow including the depressor supercilii, the corrugators, and the procerus. The frontalis muscle is the principal brow elevator. Based on the literature, I concluded that cosmetically objectionable forehead rhytides are produced by antagonist activity to the eyebrow depressors. I hypothesized that by selectively treating the brow depressors with cosmetic botulinum toxin, it should be possible to soften and possibly elevate the brows without paralyzing the forehead or causing blepharoptosis. Injectors had been cautioned to keep botulinum toxin injections 1 cm or more above the orbital rim to reduce the risk of ptosis. Empirically, I found I could achieve significant treatment of the superior orbital orbicularis oculi muscle by injecting microdroplets (10 to 30 μl) of botulinum toxin solution 1 to 2 mm below the skin surface along the brow and glabellar musculature with virtually no incidence of upper eyelid ptosis. A treatment pattern (Fig. 1) involves 60 to 100 microinjections with a total dose of 30 to 50 U of onabotulinum toxin. The toxin is effectively trapped in the subdermal connective tissues where the muscles of facial expression insert into the eyebrow. This clinically limits diffusion.Fig. 1.: A typical cosmetic microdroplet botulinum toxin forehead lift treatment pattern.I applied for a U.S. patent for this drug delivery method on May 4, 2006. The application was published on November 8, 2007, by the U.S. Patent and Trademark Office. U.S. patent 7846457 B2 was granted on December 7, 2010, for this method. This included a very vigorous prosecution of the patent application, including a very detailed and robust analysis of prior art. There was no evidence to substantiate Dr. Wu's claim that his Microbotox method was disseminated before May of 2006. I recently published a retrospective 5-year review of 563 consecutive cosmetic microdroplet botulinum toxin A forehead lifts in 227 patients.4 The method is commercially referred to as a Microdroplet Lift. Dr. Wu's Microbotox is an intradermal treatment of the lower face and neck with interesting and useful aesthetic effects. It differs fundamentally from the cosmetic microdroplet botulinum toxin A forehead lift that I have independently described and patented. DISCLOSURE Dr. Steinsapir is the inventor of the Microdroplet Lift described in this communication and holds U.S. patent 7846457 B2 for this method. Kenneth D. Steinsapir, M.D.Division of Ophthalmic Plastic and Reconstructive SurgeryJules Stein Eye InstituteDavid Geffen School of MedicineLos Angeles, Calif.