History of Dermal Fillers
In 1893, the first fat auto-grafting was performed by Dr. Neuber, who successfully auto-grafted fat into the infraorbital margin in a man with tuberculous ostitis. In 1980’s Dr. Fournier injected fat from liposuction surgery. Average fat survival rate was around 25%. Bovine collagen was developed in the 1970’s and Zyderm implant was FDA approved in 1983. However, skin testing was necessary, because 2 – 3% of the patients had hypersensitivity reactions.
Hyaluronic Acid (HA) is the main polysaccharide in the extracellular matrix. It acts as a scaffold for collagen and elastin to bind. It also hydrates the skin, because it binds water. Skin loses elasticity and fullness due to loss of HA. Researchers were able to grow chains of the polysaccharide and cross link them. Crosslinking varied its degree of hardness, lift, duration of survival and resistance to heat and degrading enzymes. HA is now grown by a gram positive bacteria, and called NASHA (non-animal sourced hyaluronic acid) gel.
Hyaluronic acid was introduced to the US in 2003 with Restylane. Restylane® has an HA concentration of 20 mg/mL with a gel bead size of 250 μmol and 100 000 units per mL and an estimated 0.5–1.0% cross-linking. Perlane® contains 20 mg/mL of HA with a larger gel bead size of 1000 μmol and 10 000 units per mL, and less than 1% cross-linking.
Other fillers followed that contains polylactic acid, calcium hydroxylapatite, and etc. In addition to volume replacement, these fillers stimulate host response and endogenous collagen production.
Hyaluronic Acid has the following favorable qualities:
- Effective, long lasting and degradable
- Allergy testing is not required
- Similar to normal tissue texture
- No special storage requirement
- No need for mixing or preparation
- Typically it does not migrate nor calcify
Hyaluronic Acid is a component of the extracellular space. In your body, it maintains structure by binding water and increasing volume. It also is a source of protection and lubrication of your tissues. Hyaluronic Acid decreases with age. This is also why it is an ideal dermal filler agent with good bio-compatibility.
In the injectable form it is a polysaccharide compound. It stabilizes in the tissue by cross-linking which increases tissue residency. Unmodified Hyaluronic Acid has half life of 24 – 48 hours. Other medical uses of uncross-linked Hyaluronic Acid include injections in to joints or formulations on topical products. Hyaluronic Acid binds water after injection and increases the tissue volume. Cross-linked Hyaluronic Acid also induced fibroblasts to produce endogenous collagen.
Restylane and Perlane
Restylane-L is a gel of hyaluronic acid generated by Streptococcus species of bacteria, chemically crosslinked with BDDE (butanediol diglycidyl ether), stabilized and suspended in phosphate buffered saline at pH=7 and concentration of 20 mg/mL with 0.3% lidocaine. Restylane is a similar gel compound without the 0.3% lidocaine.
Restylane-L is indicated for mid-to-deep dermal implantation for the correction of moderate to severe facial wrinkles and folds, such as nasolabial folds. Restylane-L is indicated for submucosal implantation for lip augmentation in patients over the age of 21.
The concentration of Restylane is 20mg/mL. Restylane is implanted in the mid to deep dermis.
Restylane-L combines Restylane with lidocaine, which can help reduce discomfort during and after treatment. In clinical studies 72% of patients reported significantly less pain during treatment with Restylane-L vs. Restylane. Patients continued to experience less discomfort for up to one hour after treatment.
Perlane-L is a sterile gel of hyaluronic acid with 0.3% lidocaine. The median particle size is between 750 and 1000 microns. Perlane is a similar gel compound without the 0.3% lidocaine.
Perlane-L is indicated for implantation into the deep dermis to superficial subcutis for the correction of moderate to severe facial folds and wrinkles, such as nasolabial folds.
The concentration of Perlane is 20mg/mL. The difference between Restylane and Perlane is that Perlane has a larger gel particle size than Restylane. Perlane is implanted into the deep dermis. Therefore, Perlane is a better choice for more severe facial wrinkles that benefit from a deeper injection into the skin. By combining lidocaine with Perlane, Perlane-L helps reduce discomfort during and after treatment. In clinical studies 95% of patients reported significantly less pain during treatment with Perlane-L vs. Perlane. Patients continued to experience less discomfort for up to one hour after treatment.
In clinical trials, Restylane persists in the skin for about 6 months. Perlane persists in the skin for at least 6 months in a majority of patients. Clinical studies show no significant safety profile difference between Restylane and Perlane. Both products are biocompatible with the body’s natural hyaluronic acid and no allergy testing is required.
Learn more about Clinical Study of Restylane® / Perlane®.