Fine-tuning, tailoring botulinum toxin injection techniques

Since the advent of the use of botulinum neurotoxin-A (BoNT-A) in aesthetic medicine, physicians have been striving to maximize cosmetic outcomes by varying the doses as well as employing different injection techniques.

"Whether we are treating glabellar lines, crow's feet, perioral and cervical rhytides, or any of the other common target areas with botulinum toxin, to maximize positive as well as longer lasting cosmetic results, it is paramount to look at each patient individually and accurately assess the bone and muscle structure of the individual patient and his or her specific pattern of wrinkling," says Berthold Rzany Sc.M., M.D., of the department of dermatology and allergy at the Charite University of Medicine, Berlin.

Categorizing wrinkles

He divides his patients into kinetic, hyperkinetic and hypertonic wrinkle groups.

He says that combining botulinum toxin A with fillers like collagens or hyaluronic acid has a two-pronged effect. Facial rejuvenation can be achieved by relaxing the mimics with botulinum toxin and reinflating via the fillers. Also, their combined use seems to have an effect on the longevity of the injected filler and therefore the positive aesthetic result lasts longer.

"Evaluating the patients by muscle pattern allows for a more individualized treatment. The physician must be wary though when assessing the muscular patterns of patients, as they may be hyperkinetic in one area and hypokinetic in another," Dr. Rzany notes.

Dr. Rzany explains that there are micro- and macroinjection techniques that can be used separately or combined. The microinjection technique consists of an intradermal injection of very small amounts (e.g. < 0.02 ml) of BoNT-A.

"The rationale of the microinjection technique is to avoid adverse events in standard areas, as well as to approach new areas where an overdose might be strictly avoided," he says.

Dr. Rzany also likes to combine the micro- and macroinjection techniques when individualizing botulinum toxin treatments. He says that in the crow's feet area, he likes to give two lateral standard macroinjections, and then four to five microinjections, achieving very positive results.