Soft Tissue Volume Fillers in the Treatment of HIV-associated Facial Lipoatrophy
With the continuous need for re-injections, transient fillers are not a cost-effective alternative for the desired long-lasting result in patients suffering from facial lipoatrophy.
Slowly biodegradable fillers are often different combination gels that consist of a solid component (microspheres or fragments) in a transient gel carrier. The filling effect is achieved by a process whereby the gel carrier is rapidly degraded and the microparticles trigger a foreign body response and subsequent fibrosis through de novo collagen production. The solid component can be polyl-L-lactic acid (PLLA), as in Sculptra, also known as New-Fill® (Sanofi-Aventis, Bridgewater, NJ) or calcium hydroxylapatite (CaHA), as in Radiesse® (Bioform Medical Inc., San Mateo, CA) and is slowly degraded over two to three years.
The most common complication due to these fillers is tissue hardening due to over-collagenisation and the appearance of palpable, non-visible micronodules.6,10–12
Figure 1: Tissue Integration of Aquamid® Two Years After Injection
This can, in the worst cases
result in the formation of granulomas. In most cases, bacteria have not been identified and can be treated with steroids. The current theory behind the development of granulomas several years after the injection is localised de novo collagen production triggered by non-co-ordinated degradation of microparticles.
in contrast to PAAG, which is hydrophilic. Moreover, PAAG will interact with the surrounding tissue as a consequence of the high water content and structure and in the case of Aquamid® and Aquamid® Reconstruction (Contura International, Soeborg, Denmark) several studies have shown that the gel will integrate into the surrounding tissue through a fine network of vessel-bearing connective tissue six to 12 months after injection (see Figure 1).13 of hyaluronic acid gel,14
The non-biodegradable fillers can be smooth gels without microparticles, such as polyacrylamide gel (PAAG) and silicone, or combination gels where the solid component is permanent (polymethylmethacrylate, as in Artefil, Suneva Medical Inc., San Diego, CA). Non-biodegradable combination gels have the same mechanism of action and adverse events as biodegradable combination gels, with considerable foreign-body response and fibrosis. After injection with smooth gels, the foreign-body reaction is mild (PAAG) to modest (silicone). Silicone is hydrophobic and has been shown to have a tendency to migrate from the implantation site via circulating phagocytic cells,6,10
Apart from partial integration extensive tissue integration has not been
demonstrated in other gels, either permanent or transient (unpublished data, Lise Christensen).
Aquamid Reconstruction has been used successfully since 2001 to restore facial lipoatrophy. It is atoxic, highly biocompatible and stable. The filling effect is achieved by the injected gel volume and when injected as multiple small deposits, the gel is readily integrated into the surrounding tissue. The result is thus permanent, soft and natural to the touch, with no repeated treatments (see Figure 2). Another PAAG, polyalkylimide (Bio-Alcamid®, Polymecon, Italy) is, in contrast to Aquamid, injected in one session as a large deposit and forms an encapsulated inert implant. In contrast to combination gels, where late-stage-complications are mostly of inflammatory origin and treated with steroids, the late-onset complication of polymer hydrogels is a low-grade chronic infection due to bacteria growing within the gel. These infections can occur several years after the injection due to occasional contaminating bacteria that are allowed to grow unnoticed in the gel deposit, leading to the formation of
EUROPEAN INFECTIOUS DISEASE
The vessel-bearing network is visualised and stained pink with van Geison and the Aquamid® gel is stained blue with Alcian blue (image courtesy of Lise Christensen).
Figure 2: Treatment of Facial Lipoatrophy using Aquamid® Reconstruction
Left: before treatment; right: two years after treatment with Aquamid®Reconstruction. biofilm.15,16
The high water-binding capacity, tissue integration and constant exchange of water between gel and surrounding tissue as seen with Aquamid and Aquamid Reconstruction is hypothesised to prevent the formation of biofilm.12
While steroids may have a good
effect on granulomas and fibrosis after treatment with combination gels, low-grade infection after Aquamid injection should be treated with broad-spectrum antibiotics in high dosage.12,17
Steroids or non-steroidal anti-inflammatory drugs (NSAIDs) are contraindicated.
Two partially randomised clinical studies have compared different interventions for the correction of HIV-associated facial lipoatrophy, including PAAG (Aquamid), polylactic acid (New-Fill) and autologous fat transfer.18,19
Clinical efficacy, safety of the techniques and short-term patient satisfaction were reported to be comparable. With a longer follow-up period of 48 weeks, Aquamid was concluded to provide the longest-lasting result.18
This is in agreement with several other reports
on the long-term aesthetic results of Aquamid for the repair of facial lipoatrophy and facial soft tissue augmentation.20–23
Biocompatibility,
safety and patient satisfaction have been reported to be stable over the long term.20,22,24,25
Aesthetic procedures are well-tolerated and feasible techniques used to treat HIV-associated facial lipoatrophy. In this specific patient group, safety and a durable result is of importance. The use of Aquamid and
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