| AESTHETIC SOLUTIONS | ARTICLE
Figure 1 Intradermal injections of cross-linked hyaluronic acid
Figures 2 and 3 (below)
Intralesional injections of hyaluronidase
allergic reaction. Performing this test is quite simple: 1500 IU of hyaluronidase are diluted in 8–10 ml saline solution, with each ml containing up to 150 IU. Then, 0.1 ml of this dilution is injected subcutaneously to the forearm. The patient is kept in the clinic for an average of 60 minutes. Any reaction (e.g. itching, swelling, redness) at the injection point signifies that the patient should not receive treatment. A subcutaneous test is recommended for all patients prior to the injection of hyaluronidase.
Hyaluronidase for reducing the risk of necrosis after an excess of hyaluronic acid Hyaluronidase, by quickly breaking down the hyaluronic acid polymer, is able to reduce the risk of skin necrosis secondary to vascular compression if injected early, according to the medical literature2–4
. Unfortunately,
injection after 24 hours has been shown to be rather inefficient. Kim et al2
experimented using intra-arterial
injection of hyaluronic acid in a rabbit ear, followed by an injection of hyaluronidase both 4 and 24 hours later. A late injection did not reduce the size of necrosis, while an earlier injection significantly reduced the size of skin necrosis. Hyaluronidase should therefore be immediately injected in cases of symptoms suggesting vascular compression .
Hyaluronidase in cellulite treatment or post-lipoplasty fibrotic reaction Hyaluronidase has been widely used in the past to treat fibrotic cellulite: 1500 IU are diluted in 8–10 ml of saline solution and deeply injected (more than 1 cm deep) in fibrotic areas. A maximum of 3000 UI are used per session for a maximum of two sessions (one per week) in order to limit the risk of allergic reactions. Allergy tests should be performed before every injection. The authorsÕ experience has found that the early injection of hyaluronidase has been able to reduce fibrosis and remaining oedema following breast lipoplasty or double chin lipoplasty in male
patients. Breast and chin lipoplasties often induce a strong fibrotic reaction that disappears slowly, sometimes over a number of months. The injection of hyaluronidase also allows for a dramatic reduction or disappearance of postoperative fibrosis in a matter of days. One injection of 500 UI hyaluronidase (1500 UI diluted in 9 ml saline solution; inject 3 ml in a fan pattern) will be sufficient for post-lipoplasty double chin fibrosis reduction. Massage is carried out immediately after injection in
order to allow a better diffusion of the product. During the massage, the doctor can feel that the fibrosis is immediately decreased. Intradermal tests should be carried out before every injection session to verify the absence of a type I allergy to hyaluronidase.
Hyaluronidase, by quickly
breaking down the hyaluronic acid polymer, is able to reduce the risk of skin necrosis secondary to vascular compression if injected early, according to the medical literature.
Hyaluronic acid filler excesses The injection of hyaluronidase fortunately erases any cross-linked hyaluronic acid very quickly, but the speed will generally depend on the strength of the cross-linking. In these cases, the delay between the injection of hyaluronic acid and hyaluronidase is not relevant ® even when injected years later, hyaluronidase is able to cut the polymer. Reports show that hyaluronidase is able to dissolve hyaluronic acid injections in the periorbital area, even 5 years after the original injection. Again, intradermal testing should be carried out prior to injection. The task is to evaluate the volume and concentration of hyaluronidase to be injected in order
prime-journal.com | April/May 2012 ❚ 35
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