What is hyaluronic acid?
Hyaluronic acid is a natural glycosaminoglycan found in all living organisms. High concentrations are found in soft connective tissue and in the fluid surrounding the eye. It is also present in some cartilage and joint fluids, and in skin tissue.
In skin tissue, hyaluronic acid is a jelly-like substance that fills the space between collagen and elastin fibres. The role of hyaluronic acid in the skin is to:
- Produce a stable viscoelastic network to bind collagen and elastin fibres
- Provide a mechanism to transport essential nutrients from the bloodstream to living skin cells
- Hydrate the skin
- Act as a cushioning and lubricating agent against mechanical and chemical damage.
Over time, either through the natural process of skin ageing or through exposure to environmental factors such as pollutants and sunlight, the body's natural store of hyaluronic acid is degraded and destroyed and resulting in disorganised clumps of collagen and elastin.
Synthetic hyaluronic acid
Synthetic forms of hyaluronic acid are used to correct disorders in the fields of dermatology, rheumatology, ophthalmology, and wound repair. Brand names of manufactured hyaluronic gels used for facial augmentation include Hylaform® (includes Hylaform Fine Line and Hylaform Plus – Hylan B), Restylane® (non-animal stabilised hyaluronic acid), Perlane®, Juvederm®, Rofilan Hylan® and AcHyal®.
A hyaluronic acid implant is a non-surgical procedure to soften facial lines and furrows. Tiny quantities of hyaluronic acid are injected through very fine needles into the dermis. Depending on how many lines are treated, the treatment takes 20 minutes to an hour, with minimal discomfort (especially with products that contain local anaesthetic agents). The hyaluronic acid increases the volume of the dermis, softens and hydrates it.
The effects can be maintained by small ‘top-up’ treatments as required, generally about twice a year.
What defects are suitable for hyaluronic acid implants?
Hyaluronic acid injections improve the skin contour and reduce depressions in the skin due to scars, injury or lines, for example:
- Frown lines between the eyebrows (glabellar lines; a risky site)
- Smoker's lines — vertical lines around the mouth (perioral lines)
- Marionette lines at the corner of the mouth (oral commissures)
- Worry lines that run across the forehead (forehead lines)
- Crow's feet at the corner of the eyes (periorbital lines)
- Deep smile lines that run from the side of the nose to the corners of the mouth (nasolabial furrows)
- Cheek depressions
- To redefine the lip border
- Acne scars
- Some other facial scars.
Am I suitable for hyaluronic acid therapy?
Almost all people are suitable for hyaluronic acid therapy. Because hyaluronic acid is chemically identical within and between species, allergy to it is very rare. Thus, unlike bovine collagen implants, there is usually no need to perform a skin allergy test. You should discuss with your doctor about whether or not you require a skin allergy test with hyaluronic acid before commencing therapy.
Hyaluronic acid therapy is suitable for patients allergic to bovine collagen.
How is hyaluronic acid treatment given?
Treatments are carried out at a medical centre by a trained doctor or supervised nurse. A careful discussion should take place to determine which areas will be treated and to explain the benefits and risks of the procedure.
Procedure for hyaluronic acid treatments
- The patient should be sitting upright.
- The face should be thoroughly washed.
- The treatment area is wiped with an antiseptic.
- A local anaesthetic may be used to numb the treatment area.
- Injection methods include serial intradermal punctures (series of small injections with a very fine needle [27–30 gauge]), tunnel, linear threading technique (the needle is withdrawn as the hyaluronic acid is injected), or fanning with retrograde injection.
- Subcutaneous injections waste the material.
- Depending on the area treated, the skin may be lightly massaged to smooth irregularities and move the injected material to the most aesthetic position.
- Another one or two treatments (at least a week apart) may be necessary to achieve the desired correction.
How long does a hyaluronic acid implant last?
Hyaluronic acid implantation is not permanent. Like natural hyaluronic acid, manufactured hyaluronic acid once injected into the skin will gradually break down and be absorbed by the body. In most cases, the augmentation usually lasts anywhere between 3-9 months. To maintain the initial results, repeat treatments or top-up treatments will be necessary. Most people have 2 to 3 treatments per year.
Are there any side effects of hyaluronic acid therapy?
Hyaluronic acid therapy is generally very well tolerated. At the time of treatments, most patients report minor discomfort. This is minimised by the use of a local anaesthetic.
Immediately after treatment, the area may be red, bruised, swollen and tender; these symptoms usually improve within a few days. Do not manipulate the treated area at this stage. A cool pack can be applied.
Rarely, allergic reactions to hyaluronic acid have been reported. These present as red, swollen, indurated nodules in the injected sites and may persist for several weeks or months.
The facial danger zones include the glabella/brow, temporal region, perioral region, nasolabial fold, nose, and infraorbital region.
Hyaluronic acid fillers injected around the eye have rarely been reported to cause blindness or visual impairment due to accidental occlusion of the retinal artery. Visual loss can also be due to muscle weakness causing ptosis or ophthalmoplegia. Other rare complications have included stroke and necrosis of the skin and underlying facial structures.