Dr Kieren Bong details his technique for successful rejuvenation of the infraorbital region using hyaluronic acid (HA) fillers
The ageing process of the infraorbital area is typically characterised by bone resorption, muscle atrophy, fatty tissue volume loss and thinning of the skin. Traditionally, infraorbital rejuvenation involves surgical excision of excess skin, muscle and fat, with the philosophy that facial ageing is characterised by excess tissue. Rejuvenation of this region has evolved considerably over the past decade and we now better understand the anatomy and pathogenesis of ageing in this area. It is generally accepted that volume restoration of the infraorbital region should form part of a comprehensive rejuvenation strategy and, historically, this was achieved through the use of collagen (bovine or human), hyaluronic acid (HA, animal or non- animal based), autologous fat and poly-L- lactic acid.1 Though our understanding of these anatomical concepts has evolved, these various volume replacement methods have presented challenges, limitations and complications.2 Today, patients appear more interested in a less invasive approach. The advent of HA dermal fillers, especially those specifically formulated for this facial area, offer a viable option to rejuvenate mild to moderate deformities in the infraorbital region, providing patients with what I believe is a safe and effective treatment option, without the down time and costs normally associated with surgery.
Once injected, HA undergoes a slow process of isovolumetric degradation by enzymatic action of hyaluronidase, offering a longer duration of correction.3 HA dermal fillers now encompass the majority of the temporary dermal filler market.4 I believe this is due to the advantages of HA, finding it to have longer duration (6-18 months), no need for skin testing, relatively low risk of product-related side effects, and better pliability. Another major advantage is the option
of dissolving the HA filler in the event of over-correction, or too superficial a placement.
Sound understanding of the anatomy in this region is absolutely essential for safe and effective rejuvenation of the infraorbital region. The anatomy of this region over the bone (Figure 1) consists of:5
The bony orbit forms the foundation for the peri-orbital complex. Orbital fat is held in place and contained by the orbital septum, which runs from the orbital rim to the tarsal plate. The OOM is a broad sphincteric muscle, which covers the tarsus, septum and bony orbit. It is a pivotal supporting structure for the eyelid and inferior orbital fat. Deep to the inferior OOM lies the SOOF. Inferior to the OOM lies the malar fat pad.6
Ageing may cause pseudoherniation of inferior orbital fat, secondary to weakening of the orbital septum. This results in a protuberance of the lower eyelid.1 Loss of volume in the mid face, coupled with translocation of malar fat pad inferiorly, causes increased exposure of the inferior orbital rim and subsequently relative surface depression and an apparent increase in lower eyelid length.1 The loss of osseous support through bone resorption, muscle atrophy, loss of fatty tissue volume and thinning of the skin all contribute toward the formation of tear trough in infraorbital hollows.1
Also known as the nasojugal groove, the tear trough is a depression extending infero-laterally from the medial canthus. It is demarcated superiorly by the infraorbital fat protuberance. The inferior border is formed by the skin of the upper cheek, suborbicularis oculi fat, and portions of the malar fat pad.3
Infraorbital rejuvenation with HA dermal fillers is challenging. Apart from understanding the anatomy and pathogenesis of ageing in this region, clinicians should have considerable experience with injectable fillers and familiarity with the behaviour of the HA being used.
Identifying the correct indication is the key to success. Physical examination and history should ascertain signs of oedema and fluid retention. If the patient describes noticeable swelling in the morning, this is usually indicative of fluid retention or localised lymphatic drainage impairment. Careful pre- procedural photography is vital.
The chair’s backrest is reclined 30° from the upright position and the patient’s head should rest firmly against the headrest. A ‘snap test’ is performed to ensure there is no excessive palpebral laxity. I advocate marking out the treatment area, delineating the upper and lower borders of the tear trough. The infraorbital rim should be actively palpated and marked out.
The HA dermal filler may be administered with a hypodermic needle, although I prefer the use of a blunt micro-cannula in this region. I tend to use a 27G micro- cannula for a more homogeneous placement of filler. Despite having a blunt tip, a 27G micro-cannula is capable of lacerating blood vessels with excessive force.
Placement of the filler should be just above the periosteum, beneath the OOM and immediately inferior to the orbital rim. Small aliquots of filler are precisely injected along the infraorbital rim to help soften the transition between orbital fat and malar fat, and, accordingly, the appearance of infraorbital hollows. With a hypodermic needle, aspiration prior to each injection is advisable to minimise the risk of intravascular injection, and I recommend a serial puncture technique. Bruising may occur when the needle passes through the OOM. The infraorbital rim gives clinicians an idea of where the orbital septum lies, and care should be taken to avoid injection through this structure because this will exacerbate the pseudoherniation of orbital fat.1 Exerting mild pressure with the index finger of the contralateral hand at the orbital margin helps to avoid injection through the orbital septum.
Some patients may require concurrent volume replacement in the mid-face in order to achieve satisfactory results, which should be established and discussed prior to the procedure.
Post-injection, gentle massage may be necessary to minimise surface irregularity, although this should not be necessary if the clinician has decided on the correct HA dermal filler for the patient. Gently place ice packs on the area to promote vasoconstriction. I discourage patients from carrying out any deep tissue massage of the area for three weeks.
Avoid depositing large volumes of the filler in one location, if possible. In fact, I always under-correct procedures and schedule a review appointment for possible touch up four weeks post-treatment.
I have found that transient side effects such as injection site inflammation, including erythema and discomfort, are generally associated with the use of hypodermic needle. These typically resolve within one or two days and can be minimised with extra care during injection and with the use of a blunt micro-cannula. I believe that the use of non-particulated HA dermal fillers with a relatively low percentage of crosslink may help too.
Post-treatment, mild oedema is another known adverse event and can occur between 6% - 26% of injections.8 Although tissue trauma can cause mild swelling, post-procedural oedema in this area is usually caused by using incorrect HA filler. HA is intrinsically hydrophilic and, as such, I think the risk of this adverse event may be minimised with the use dermal fillers of relatively low HA concentration.
The ‘Tyndall effect’ may occur with too superficial a placement of HA and is more commonly observed when particulated dermal fillers are used in this region.2 This presents as a bluish hue just beneath the skin and can be corrected very easily with the injection of hyaluronidase.9 If indicated, the treatment may be repeated within one to two weeks by re-injecting the filler at a deeper plane, beneath the OOM.
Infection is possible although the risk can be minimised through judicious use of antiseptic prior to the treatment and observing a strict protocol for infection control.10
Injection necrosis is a rare but clinically significant complication. This may present as vascular interruption at the treatment site with subsequent localised tissue necrosis or intra-arterial injection of filler resulting in distal embolic events.3 Localised vascular interruption is more likely associated with more viscous fillers.1 I would advise minimising the risk with the use of a blunt micro-cannula.
Product migration can also occur, caused by the migration of product from the deep plane through the dissociation of the OOM or too superficial a placement of HA dermal fillers. Apart from injecting the filler supra-periosteally beneath the OOM, I always under-correct and advise against aggressive massaging after the treatment, especially in older patients. Choosing a product that has the correct balance between reticulated HA and free HA is beneficial.
I would describe free HA as like a lubricant – it makes the injection process easier and smoother, but equally too high a concentration of free HA means the product has the propensity to spread and migrate.
Although technically bacteria-derived HA dermal fillers are non-immunogenic, there is a theoretical risk of hypersensitivity against the impurities, which remain after the purification of HA.11 In essence, it is my opinion that an ‘ideal’ HA dermal filler for the purpose of infraorbital rejuvenation should possess the following features:
The approval of HA dermal fillers for the treatment of lines, wrinkles and volume replacement has considerably expanded the cosmetic armamentarium. Despite our evolving understanding of the anatomy in the infraorbital region, treatment of the tear trough and infraorbital hollows remains a challenge. The wide variety of dermal fillers available to treat different areas of the face have allowed clinicians to optimise their results and individualise treatment plans to suit the patient’s needs. The appropriate selection of filler, correct injection techniques and patient selection are keys to success.
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