This month we will switch gears and discuss some trends in non-invasive oculoplastic surgery. This article will start out with information about botulinum toxin injections, then next month we will focus on dermal fillers.
For many years now, non-surgical aesthetic enhancements have way outnumbered surgical aesthetic enhancements. Patients seek ways to achieve rejuvenation without having to undergo the knife, which can be associated with a hefty downtime. Also, there are many great products, methods and devices that will provide patients with visible results without the downtime necessary for surgery. Out of the non-surgical procedures, by far the most popular year after year are botulinum toxins, followed by hyaluronic acids (ASAPS statistics). Procedures using devices are the next most popular and will be discussed in the next article.
Aesthetic injectables have not only become popular amongst consumers, but are a common addition to many practices, beyond the core specialties (oculoplastic surgery, facial plastic surgery, dermatology and plastic surgery). When appropriately trained and equipped in an office, aesthetic injectables can prove to be a lucrative and enjoyable arm for many health care providers, physicians and non-physicians.
Botulinum Toxins Types & Uses
There are three commercially available, FDA approved botulinum toxin type As — Botox®, Dysport® and Xeomin®. All have the cosmetic indication for injection of the glabella, however, Botox also has the indication for lateral canthal lines.
Most are familiar with the three main areas of upper face injections, including the frontalis to soften the horizontal forehead lines, the glabella to treat the 11 lines between the brows, and the orbicularis oculi to minimize crow’s feet. Take caution with injections to the crow’s feet in patients with dry eyes, as this can weaken the tone of the lids and alter lid closure and distribution of the tear film.
Injections that are also popular in the upper face are the bunny lines (nasalis) and the lateral brow, targeting the superolateral orbicularis oculi in order to create a 1 to 2 mm chemical brow lift. Combining a lateral brow lift with the glabellar injections can lift the entire brow area and open up the periocular region.
In the lower face, injection of the depressor anguli oris can help to reverse down-turned corners of the mouth. Toxin to the orbicularis oris can help to soften vertical lip lines (smoker’s lines or “the bar code”). If someone has a dimpled chin, injection into the mentalis can help. Platysmal bands can be treated and if this technique is combined with small injections along the jaw line where the platysma inserts, one can create a subtle neck lift otherwise known as the Nefertiti Lift, after the late Egyptian queen. Massateric hypertrophy is a popular injection in Asia. Repeat injections in this area can gradually lessen the bulk of this muscle and thin the lower face.
Functionally, botulinum toxins can be used around the eyelids. For thyroid lid retraction, the eyelid can be everted and the injection given subconjunctivally just above the tarsal plate to drop the eyelid. For aberrant regeneration after seventh nerve palsy, an injection can be given the pretarsal orbicularis, which can effectively decrease the ptosis that is induced during jaw movements.
Companies have been investigating topical botulinum toxins for years now. This topical application avoids the need for needle sticks, which many patients fear, but requires an occlusive administration of at least 30 minutes in the office. Potential best uses would be for large areas that require multiple injections, such as axillary hyperhidrosis. Additionally, painful injections would benefit from a topical product, such as the fingertips and palms for hyperhidrosis.
Further Research
Novel uses for botulinum toxins that are still being investigated include injections for wound healing, for the treatment of rosacea, and for use as a vehicle for anti-cancer drugs.
The use of botulinum toxin for improved wound healing has been written about by Jablonka et al. Dynamic tension on healing wounds is created by the musculature beneath the wound, which, when it contracts, creates microtrauma inducing prolonged inflammation and increased metabolic activity during wound healing. More collagen and glycosaminoglycan deposition occurs leading to hypertrophic and hyperpigmented scars. As well, wounds under tension have a compromised blood supply and increased fibroblastic response. Botulinum toxin can be used to chemoimmobilize the area around and beneath the wound to eliminate dynamic muscle tension.
Jablonka et al reviewed both animal and human studies that have been conducted using botulinum toxin in healing wounds. The results were favorable and the safety profile excellent. Their recommendations were advanced botulinum toxin injection in the case of elective incisions and encouraged availability of botulinum toxin in urgent and emergent care settings to allow for injection at the time of closure of lacerations.
Gugarell et al studied varying concentrations of botulinum toxin in vitro on re-epithelialization and angiogenesis. Three concentrations of toxin were exposed to human keratinocytes and endothelial cells. Proliferation and migration of the cells were observed and also the angiogenic potential of endothelial cells in vitro. What they found was that high concentrations of botulinum toxin interfered with wound closure as keratinocytes’ proliferation and migration were deteriorated. Also, toxin at concentrations of 20 IU/mL constrain in vitro vessel formation but do not influence proliferation or migration of endothelial cells.
Dayan et al published an article on the use of botulinum toxin for the treatment of rosacea in 2012. They found that microdroplets of the neurotoxin in the flushed cheek region in rosacea patients worked to decrease inflammation. The proposed mechanism of action is the inhibition of vasoactive intestinal peptide (VIP) and acetylcholine. These two neurogenic peptides are linked to inflammation and vasodilation in rosacea. There are other neuropeptides involved in sebaceous activity, vascular homeostasis and inflammation, which may also play a role in how botulinum toxins work against rosacea.
And Faherer et al discovered that genetically engineered bacterial protein toxins can be used for delivery of exogenous proteins into the cytosol of mammalian cells. The binary C2 toxin from C. botulinum was used as the delivery vehicle, which rests on its binding/translocation component C2IIa and the genetically modified adaptor domain C2IN that act in concert to trigger cell uptake.
Part V of this series will focus on dermal fillers — basics as wells as new trends.