By Jerome Edelstein, MD
What is Hyaluronidase?
Hyaluronidase is a soluble protein enzyme that is typically used to break down the hyaluronic acid found in dermal filler injection treatments like Juvéderm® and Restylane. The solution works by breaking up — and helping the body to reabsorb — the filler introduced to the body during the hyaluronic acid injection. It accomplishes this by increasing tissue permeability, splitting the molecular bonds holding the hyaluronic acid together and promoting the natural cellular processes responsible for its diffusion.
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Its ability to quickly disperse chemical agents makes hyaluronidase ideal for applying anaesthesia as well. For this reason it may be added to local anaesthetic solutions in order to increase their area of effect and onset speed.How Does Hyaluronidase Work?Hyaluronidase treatment is usually recommended to patients who have had hyaluronic acid injections and are unhappy with their results. When hyaluronidase is injected (as an enzyme solution) beneath the skin of a previously treated area it is able to speed up the body’s natural ability to break down the filler product. This process works to reduce the effect of the filler injection, reversing the undesirable results.
This trait gives cosmetic surgeons the ability to quickly correct misplaced injections, protect patient safety and ensure satisfactory aesthetic results. Before hyaluronidase became available, any error in hyaluronic acid injections required patients to wait for the filler to naturally dissipate over several months. A study that monitored the substance’s ability to eliminate unsatisfactory results found that “the use of hyaluronidase reduced patient discomfort within 24 to 48 hours, deterring any patient anxiety or patient dissatisfaction.” How Does Hyaluronidase Work?A two-part study published in Journal Watch Dermatology, conducted in 2005, recorded evidence of hyaluronidase’s ability to break down cosmetic injectables. The first part of the study saw a group of twelve healthy volunteers receive two separate injections (0.2mL of non-animal stabilized hyaluronic acid, or NASHA) to sites located on their forearms. Several days after the gel was introduced, a blinded evaluator assessed and recorded changes to the subjects’ forearm skin. One of the previously injected sites was then treated with hyaluronidase while the other received saline solution. Four to seven days following the introduction of hyaluronidase, 80% of the NASHA gel had disappeared. The site injected with saline still possessed almost all of it, specifically 90% of the gel.
The second part of the study studied a new group who received NASHA injections at three different sites located on their forearms. After three to five days, hyaluronidase was injected to each site at different levels of concentration (30, 20 and 10 units). Four to seven days following this step of the study the researchers recorded no palpable gel in the 30 unit site and a decrease in the 20 and 10 unit sites. After two weeks the gel in the 20 unit sites had disappeared. The gel remaining in the sites that had received 10 units of hyaluronidase took four weeks to dissolve.
Researchers concluded that “hyaluronidase injections were useful in reducing ” and that “larger doses completely eliminate from the implantation site.”