Full scope of effect of facial lipoatrophy: a framework of disease understanding

Management of Tear Trough with Hyaluronic Acid Fillers: A Clinical-Practice Dual Approach

Introduction

Tear trough deformity (TTD) is currently a major concern for many individuals that seek periorbital rejuvenation. Among the different options currently available for treating TTD, hyaluronic acid (HA) filler injections have become increasingly popular.

Purpose

To provide a dual approach, direct and indirect strategies for treating TTD with HA fillers according to patient facial structure.

Methods

The current paper combined the authors’ experience with the currently available scientific evidence.

Results

The current study presents the authors clinical experience regarding TTD treatment and serves as a guide on the best therapeutic approach with HA fillers. For achieving good aesthetic outcomes, especially in TTD, it is crucial to have a detailed understanding of both facial anatomy and the individual characteristics of the HA fillers. Proper management of full-face facial rejuvenation should have into consideration three main pillars: structure, contour, and refinement.

Conclusion

Treatment of TTD should be addressed from a comprehensive perspective, including potential lack of structural support, as well as interventions on the dynamic processes involved in the problem. Additionally, HA fillers can be used to modulate mechanically muscle movement by either facilitating their action or decreasing contractility by reducing their movement. Clinicians can benefit from ongoing guidance on the use of these products in order to tailor and optimize treatments to patient’s requirements. Although HA filler injections have low rates of side effects, TTD was listed as the most challenging area to treat with HA. Therefore, TTD treatment should be performed only by well-trained and experienced specialists.

Acquired facial lipoatrophy: A report of 3 cases with imaging features

Acquired facial lipoatrophy is a rare disease with an unclear etiology and pathological pathway. The distinct causative factors of this disease have been not elucidated, but it is suspected to be associated with immune system-related diseases, most notably AIDS. Although the management of facial lipoatrophy is very important for patients' social life and mental health, no treatment framework has been developed due to the unknown nature of the disease manifestation. The present case report was designed to provide sequential imaging to visualize the disease progression. The clinical backgrounds of the patients are also introduced, helping characterize this disease entity more clearly for maxillofacial specialists.

Idiopathic facial lipoatrophy in a healthy middle-aged woman: a case report

Background

Facial lipoatrophy is a rare condition described by the disappearance of facial subcutaneous fat. The etiology of lipoatrophy can be congenital, or acquired including traumatic, iatrogenic or idiopathic. Idiopathic facial lipoatrophy has only been previously identified in three case reports, among which, the patient demographics vary considerably. Two of these case reports have identified a role for autologous fat transfer as a means of treatment. This case differs from those in the literature in patient demographics and severity of the facial lipoatrophy. The aim of the current report is to present a rare case of idiopathic facial lipoatrophy, and to assess the use of autologous fat transfer as a treatment modality.

Case presentation

We present a case of a 40-year old woman from Nova Scotia, Canada who presented with asymptomatic idiopathic facial lipoatrophy. The patient was otherwise healthy, taking no medications with no trauma or surgery in the region affected. Investigations, including a full autoimmune workup, were unremarkable. The facial lipoatrophy was considerably disfiguring and was assessed as a Grade 4 on the facial lipoatrophy scale. The patient was treated over the course of 2 years with two autologous fat transfers.

Conclusions

Achieving resolution of idiopathic lipoatrophy is important to patients because it can manifest in a disfiguring form and have negative effects on quality of life. The current study reports a treatment of idiopathic lipoatrophy that achieved results acceptable to the patient.

Treatment of facial lipoatrophy, morphological asymmetry, or debilitating scars with the hyaluronic acid dermal filler Princess® FILLER

PURPOSE

The aim of this study was to evaluate the effectiveness and safety of hyaluronic acid (HA) dermal filler when used in the face for medical reconstructive purposes.

PATIENTS AND METHODS

Adult patients with moderately severe facial lipoatrophy (FLA), morphological asymmetry (MA) of the face, or debilitating scars (DS) on the face were included in a prospective, noncomparative, multicenter, postmarket clinical follow-up study. All patients were treated with an HA filler (Princess® FILLER), which was injected intradermally on study Day 1, with optional touch-up 2 weeks later. The effectiveness of the treatment was evaluated at Weeks 4 and 24, using a six-grade scale ranging from "excellent" to "worsening". The assessments were conducted by both the investigator and the patient and, at Week 4, by the independent photography reviewer as well. Adverse events were collected at each visit.

RESULTS

Fifty-three patients were included in the study (FLA 23, MA 17, and DS 13), and 46 patients completed a 6-month follow-up (FLA 20, MA 15, and DS 11). At Week 4 (primary endpoint), the overall treatment success rate was 100% (FLA), 100% (MA), and 94% (DS), based on assessments made by the investigator, patients, and the independent reviewer, respectively. In most patients (~95%), the effect was sustained over 6 months. Treatment-related adverse events were reported in five patients (9%) and included injection site hematoma, injection site pain, and headache.

CONCLUSION

Dermal filling with HA gel is a viable treatment option for the correction of various deformities of the face resulting from FLA, MA, or DS.

Effectiveness evaluation of two volumizing hyaluronic acid dermal fillers in a controlled, randomized, double-blind, split-face clinical study

Background

Enhancement of the midface can be achieved with volumizing hyaluronic acid (HA) fillers.

Objective

The objective of this study was to compare the safety and effectiveness of Cohesive Polydensified Matrix^® 26 mg/mL HA gel (CPM-26) and Vycross^® 20 mg/ml HA gel (VYC-20) in a controlled, randomized, evaluator-blind, split-face clinical study.

Patients and methods

Subjects with moderate-to-severe malar volume loss on the Merz Aesthetics Scale (MAS) received CPM-26 on one side and VYC-20 on the contralateral side of the face. Effectiveness assessments were performed by blinded evaluators including photographic and live MAS ratings and live Global Aesthetic Improvement Scale (GAIS) ratings. Calculations of anatomical volume variations at month 3 (M3), month 6 (M6), month 12 (M12) and month 18 (M18) were also performed.

Results

Non-inferiority of CPM-26 versus VYC-20 was demonstrated at M3 (primary end point) based on MAS. GAIS rating showed that significantly more subjects had better improvement with CPM-26 than with VYC-20 at month 1, M3, M12 and M18 (p=0.0032, p=0.0074, p=0.0384 and p=0.0110, respectively). Standardized evaluation of volume variations from baseline to M3, M12 and M18 showed that CPM-26 created more volume augmentation at all time points, and the difference was significant at M3.

Conclusion

CPM-26 was non-inferior to VYC-20 based on MAS ratings at M3 and demonstrated a favorable safety and effectiveness profile for midfacial volume enhancement with results lasting up to M18.

Efficacy and tolerance of an injectable medical device containing stable hybrid cooperative complexes of high- and low-molecular-weight hyaluronic acid: a monocentric 16 weeks open-label evaluation

BACKGROUND

An injectable medical device containing stable hybrid cooperative complexes of high- and low-molecular-weight hyaluronic acid (HA) has been developed with characteristics suited for a global improvement of facial esthetics.

OBJECTIVE

To evaluate the HA product performance in improving some key facial esthetic features. The study employed clinical scales, subjective evaluations, and facial skin objective measurements.

METHODS

A single Italian site treated 64 female subjects aged 38-60 years, with injections at five predetermined points, on each side of the face, with a 4-week time lapse between the first and the second product administration. Subjects were evaluated after 4, 8, 12, and 16 weeks, using validated clinical scales, subjective evaluation, and objective quantitative outcome measures. Assessment of esthetic results included photographic documentation.

RESULTS

Both the clinical and subjective assessments, and the majority of objective instrumental parameters indicated an improvement throughout the study and were already significant at week 4 or 8 and were still significant at week 16 (3 months after the second treatment). Minor and temporary local skin reactions were observed in 23% of subjects at the site of the injections, and the global judgment on tolerability was good or excellent, both in the investigators' opinion and volunteers' self-evaluation.

CONCLUSION

Both subjective and objective improvement of the facial parameters was consistent with the bio-remodeling purpose, and persistent and still statistically significant at the end of the study. The tolerability and safety profile of the product were judged good or excellent both by investigators and volunteers. This study supports the claim for bio-remodeling of these stable hybrid cooperative complexes of low- and high-molecular-weight HA.

Hyaluronic acid fillers with cohesive polydensified matrix for soft-tissue augmentation and rejuvenation: a literature review

Background

Cohesive monophasic polydensified fillers show unique viscoelastic properties and variable density of hyaluronic acid, allowing for a homogeneous tissue integration and distribution of the material.

Objective

The aim of this paper was to review the clinical data regarding the performance, tolerability, and safety of the Belotero^® fillers for soft-tissue augmentation and rejuvenation.

Methods

A literature search was performed up until May 31, 2015 to identify all relevant articles on Belotero^® fillers (Basic/Balance, Hydro, Soft, Intense, Volume) and equivalent products (Esthélis^®, Mesolis^®, Fortélis^®, Modélis^®).

Results

This comprehensive review included 26 papers. Findings from three randomized controlled trials showed a greater reduction in nasolabial fold severity with Belotero^® Basic/Balance than with collagen (at 8, 12, 16, and 24 weeks, n=118) and Restylane^® (at 4 weeks, n=40), and higher patient satisfaction with Belotero^® Intense than with Perlane^® (at 2 weeks, n=20). With Belotero^® Basic/Balance, an improvement of at least 1 point on the severity scale can be expected in ~80% of patients 1–6 months after injection, with an effect still visible at 8–12 months. Positive findings were also reported with Belotero^® Volume (no reduction in hyaluronic acid volume at 12 months, as demonstrated by magnetic resonance imaging), Soft (improvement in the esthetic outcomes when used in a sequential approach), and Hydro (improvement in skin appearance in all patients). The most common adverse effects were mild-to-moderate erythema, edema, and hematoma, most of which were temporary. There were no reports of Tyndall effect, nodules, granulomas, or tissue necrosis.

Conclusion

Clinical evidence indicates sustainable esthetic effects, good safety profile, and long-term tolerability of the Belotero^® fillers, particularly Belotero^® Basic/Balance and Intense.

Acquired facial lipoatrophy: pathogenesis and therapeutic options

Facial lipoatrophy refers to the loss of subcutaneous fat tissue presenting by flattening or indentation of convex contour of the face. Facial lipoatrophy is a feature of the normal ageing process. It may be also a manifestation of chronic diseases, most frequently it affects HIV-infected individuals treated with highly active antiretroviral therapy (HAART) and may constitute a complication of connective tissue diseases, like lupus erythematosus profundus or morphea. Early recognition and treatment of the active stage of connective tissue diseases is of essential significance in prevention of subsequent scarring and atrophy lesions. In HIV-positive patients undergoing HAART therapy, the attempt to modify thetreatment scheme so it has a less lipemic effect seems to be justified. Esthetic correction of facial lipoatrophy in chronic diseases is a great challenge. Improvement of appearance is very important for affected individuals, because it diminishes their stigmatization and psychosocial dysfunction. Facial volumetric correction includes surgical and dermatological procedures such as adipose transfer and injectable dermal fillers.

Antiaging, photoprotective, and brightening activity in biorevitalization: a new solution for aging skin

BACKGROUND

Age-related changes in the dermis can be considered the result of intrinsic factors and the consequence of environmental damage, mainly due to ultraviolet (UV) radiation from the sun (responsible for skin photoaging). The great versatility of the mesotherapy "biorevitalization" lies in the synergy between different biological effects of the active injected substances, which treats the skin in a more complete way. Several studies about biorevitalization efficacy showed good results. To date, however, objective results supported by instrumental evaluation are very sparse.

PURPOSE

This study evaluated the efficacy of an injectable solution (32 mg of hyaluronic acid plus an antiaging antioxidant complex consisting of vitamins, minerals, and amino acids) in the treatment of skin aging and photoaging.

METHODS

A total of 64 female volunteers (37-60 years) underwent four sessions of biorevitalization at 3-week intervals, involving multiple injections in the face (external corner of the eye and cheek), neck, décolletage, and back of the hands. The esthetic result was assessed at baseline and after 6, 9, and 12 weeks, and was established through the use of clinical and instrumental evaluations, supported by photographic documentation. Additionally, a phototest was performed to assess the effect of biorevitalization treatment on UVB-induced erythema.

RESULTS

Instrumental assessment showed, as early as after the second biorevitalizing treatment, the antiaging efficacy of the tested product; there was a clinical and statistically significant improvement of profilometric parameters, skin brightness, pigmentation, and deep skin hydration. The study product induced a statistically significant decrease of the visual score of the UVB-induced erythema compared with baseline, which was statistically different from placebo.

CONCLUSION

The study confirmed the well-known efficacy of biorevitalization in skin rejuvenation. The positive difference between deep and superficial skin hydration registered at the end of the trial suggested improved skin moisture retention of the stratum corneum. Furthermore, the obtained results suggest that the injected product could intervene at different moments of the skin pigmentation process by activating an intrinsic photoprotective mechanism and improving skin pigmentation quality. It may be that these processes employ common mechanisms in which antioxidants could play a pivotal role. This last hypothesis deserves further investigation.

Efficacy and safety of a hyaluronic acid filler in subjects treated for correction of midface volume deficiency: a 24 month study

Background

Hyaluronic acid (HA) fillers are an established intervention for correcting facial volume deficiency. Few studies have evaluated treatment outcomes for longer than 6 months. The purpose of this study was to determine the durability of an HA filler in the correction of midface volume deficiency over 24 months, as independently evaluated by physician investigators and subjects.

Methods

Subjects received treatment with Juvéderm^™ Voluma^™ to the malar area, based on the investigators’ determination of baseline severity and aesthetic goals. The treatment was administered in one or two sessions over an initial 4-week period. Supplementary treatment was permissible at week 78, based on protocol-defined criteria. A clinically meaningful response was predefined as at least a one-point improvement on the MidFace Volume Deficit Scale (MFVDS) and on the Global Aesthetic Improvement Scale (GAIS).

Results

Of the 103 subjects enrolled, 84% had moderate or significant volume deficiency at baseline. At the first post-treatment evaluation (week 8), 96% were documented to be MFVDS responders, with 98% and 100% graded as GAIS responders when assessed by the subjects and investigators, respectively. At week 78, 81.7% of subjects were still MFVDS responders, with 73.2% and 78.1% being GAIS responders, respectively. Seventy-two subjects completed the 24-month study, of whom 45 did not receive supplementary Voluma^™ at week 78. Forty-three of the 45 (95.6%) subjects were MFVDS responders, with 82.2% and 91.1% being GAIS responders, respectively. At end of the study, 66/72 subjects were either satisfied or very satisfied with Voluma^™, with 70/72 indicating that they would recommend the product to others. Adverse events were transient and infrequent, with injection site bruising and swelling being the most commonly reported.

Conclusion

Voluma^™ is safe and effective in the correction of mild to severe facial volume deficiency, achieving long-term clinically meaningful results. There was a high degree of satisfaction with the treatment outcome over the 24 months of the study.

A case of facial lipoatrophy secondary to lupus profundus managed with lipofilling technique

Facial lipoatrophy is one of the most difficult complication in the patients with lupus profundus. In this paper, we present a case of a 55-year-old woman affected by lupus profundus, with a grade V lipoatrophy, treated with lipofilling technique. No complications were observed and results at 12 months were stable, natural, and symmetric.

A comparison of the efficacy, safety, and longevity of two different hyaluronic acid dermal fillers in the treatment of severe nasolabial folds: a multicenter, prospective, randomized, controlled, single-blind, within-subject study

BACKGROUND

Commercially available hyaluronic acid (HA)-based fillers have distinct physicochemical properties related to their specific manufacturing technology, including HA concentration, cross-linking percentage, and particle size. These factors may determine treatment effectiveness, safety, and longevity; however, this requires confirmation in the clinic.

METHODS

To compare the efficacy, safety, and longevity of two distinct HA-based dermal fillers in the correction of severe nasolabial folds (NLFs), a 24 mg/mL smooth gel (Juvederm ULTRA PLUS™ [JUP]) and a 20 mg/mL particulate gel (Perlane(®) [PER]) were injected in a total of 80 normal, healthy subjects using a split face design and were followed for 12 months in this prospective, randomized, controlled, multicenter study.

RESULTS

Both fillers achieved a clinically relevant NLF correction (one point or more improvement, based on a validated NLF severity scale). However, JUP displayed greater longevity, with this correction maintained in a significantly larger percentage of NLFs after 6 months (physician's evaluation) or 9 months (subject's evaluation) and thereafter for the remainder of the study (70% vs 45%; P = 0.0002 and 62.5% vs 46.3%; P = 0.01 at month 12, based on physician and subject assessments, respectively). At month 12, 71.4% of the subjects nominated a preference for the NLF injected with JUP (P < 0.0001). Both treatments were well tolerated.

CONCLUSION

These results suggest that different physicochemical properties of HA-based fillers, associated with distinct manufacturing technologies, may influence treatment longevity in the correction of volume deficits. This may relate to a differential resistance to hyaluronidase and/or free radical degradation as previously documented in vitro.

Cost of surgical intervention for reconstructive therapy of HIV-associated facial lipoatrophy

This study aims to assess direct cost of reconstructive interventions with facial fillers for treatment of HIV (human immunodeficiency virus)-associated facial lipoatrophy (FLA). Evaluation was performed on data from patients enrolled in one arm of a comparative study of immediate versus delayed reconstructive treatment of facial lipoatrophy. Median costs were standardized for efficacy, estimated using data reported by physicians and patient reported outcomes. The variations of the results were evaluated with a sensitivity analysis. Evaluation was performed on 66 patients characterized by significant differences in terms of severity of FLA. Total cost resulted of €140,416.15, with a median cost per patient of €2126.04 (interquartile range [IQR]: 1599-2822). Taking into consideration severity of disease, median costs were €1641.67 (IQR: 1326.67-2126.04) and 2557.12 (IQR: 1939.34-2872.04) (P = 0.0) respectively for patients with low and high severity scores at baseline. Significant differences in term of cost-effectiveness ratios were also found between patients with different severity of FLA, and sensitivity analysis showed that these ratios increase with higher severity scores at baseline and vary widely depending on the costs of filler. Although these results cannot be considered representative because of important limitations, the present study suggests the severity of disease as an important determinant of costs.

Volumizing effects of a smooth, highly cohesive, viscous 20-mg/mL hyaluronic acid volumizing filler: prospective European study

BACKGROUND

Facial volume loss contributes significantly to facial aging. The 20-mg/mL hyaluronic acid (HA) formulation used in this study is a smooth, highly cohesive, viscous, fully reversible, volumizing filler indicated to restore facial volume. This first prospective study evaluated use in current aesthetic clinical practice.

METHODS

A pan-European evaluation conducted under guidelines of the World Association of Opinion and Marketing Research, the trial comprised a baseline visit (visit 1) and a follow-up (visit 2) at 14 +/- 7 days posttreatment. Physicians photographed patients at each visit. Each patient was treated with the 20-mg/mL HA volumizing filler as supplied in standard packaging. Procedural details, aesthetic outcomes, safety, and physician and patient ratings of their experience were recorded.

RESULTS

Fifteen physicians and 70 patients (91% female; mean age: 50 years) participated. Mean volume loss at baseline was 3.7 (moderate) on the Facial Volume Loss Scale. Local anesthesia was used in 64.3% of cases. Most injections (85%) were administered with needles rather than cannulas. Of the 208 injections, 59% were in the malar region, primarily above the periosteum. Subcutaneous injections were most common for other sites. The mean total injection volume per patient was 4.6 mL. The mean volume loss score declined significantly (P < .001) to 2.1 at visit 2. On the Global Aesthetic Improvement Scale, 88% and 76% of the treatments were rated very much improved or much improved by physicians and patients, respectively. Of the physicians, 95.6% rated this HA filler as very or fairly easy to use. Similarly, 92% of patients were very likely or quite likely to return for treatment; nearly all (98%) would recommend this treatment to friends. Transient (mean duration: 5.5 days) injection-site adverse events (AEs) occurred in 24 patients. Bruising was the most common AE.

CONCLUSION

The 20-mg/mL smooth, highly cohesive, viscous, volumizing HA filler was effective, well tolerated, and easy to use in current clinical practice. Participants were very likely to recommend this product to colleagues and friends, and patients would be very or quite likely to request this product for future treatments.

Assessment of ultrasound for use in detecting lipoatrophy in HIV-infected patients taking combination antiretroviral therapy

The aim of this study was evaluation of ultrasound (US) as a tool for the assessment of lipoatrophy in a population of HIV-infected patients. We enrolled a convenience sample of 151 HIV-infected Caucasian participants (males, 79%) who were treated for at least 1 year with combination antiretroviral therapy (CART) in Zagreb, Croatia. US measurements of subcutaneous fat thickness were done over the malar, brachial, and crural region. We determined sensitivity and specificity of US as a diagnostic tool for lipoatrophy using receiver-operating curves and concordant patient and clinician assessment as our reference for the presence of lipoatrophy. HIV was acquired through heterosexual contact in 50% of participants and by sex between men in 42%. The mean current CD4 cell count was 503.1 cells=mm3 (standard deviation [SD] = 250.8). Seventy-seven (51%) participants were treated with stavudine and 91 (64%) with a protease inhibitor for at least 6 months. Nineteen (13%)participants had lipoatrophy in at least one anatomic site. Sensitivity of US ranged from 67%-71%, specificity from 65%-71%, positive and negative predictive values ranged from 11%-20% and 96-97%, respectively. US diagnosed lipoatrophy was more frequently found in patients with a history of stavudine treatment and in females. Patients with lipoatrophy had a longer duration of CART than those without lipoatrophy. US is a useful tool in ruling out the presence of clinical lipoatrophy in patients on CART. Using this objective measure of subcutaneous fat may be useful in helping clinicians make decisions about changing therapy.

Lipodystrophy syndromes

Lipodystrophy syndromes comprise a group of rare, heterogeneous disorders characterized by progressive loss of fat tissue, mainly from subcutaneous compartment and occasionally affecting visceral fat. Lipoatrophy may be partial, localized, or generalized. The latter cases are usually accompanied by metabolic-related disorders, including insulin resistance, diabetes mellitus, hyperlipemia, progressive hepatic disease and anabolic state. Treatment for lipodystrophy has increased interest in recent years because a new lipoatrophic population-patients who have HIV-associated lipodystrophy--is much more numerous than the whole number of patients affected by classic lipodystrophy entities.

Approach to the human immunodeficiency virus-infected patient with lipodystrophy

Subcutaneous atrophy and central fat accumulation are common among HIV-infected patients receiving highly active antiretroviral therapy, and may be accompanied by dyslipidemia and insulin resistance. These fat changes, although commonly referred to together as lipodystrophy, are best considered as separate disorders, with distinct pathogeneses and treatment approaches. These morphological and metabolic abnormalities first appeared after introduction of protease inhibitors more than 10 yr ago, but research has demonstrated that their pathogenesis is multifactorial, with contributions from other antiretroviral medications, patient-related factors, and HIV itself. Switching to a less toxic highly active antiretroviral therapy regimen has shown partial effectiveness for the management of fat atrophy and lipid abnormalities. Lifestyle modification or surgical approaches are the treatment of choice for lipohypertrophy, although novel therapies targeting the GH axis show promise. HIV-related dyslipidemia may be difficult to treat, and can be complicated by drug-drug interactions between some lipid-lowering medications and antiretroviral medications. Treatment of diabetes in HIV-infected patients should generally follow established guidelines, but thiazolidinediones, rather than metformin, may be considered first-line treatment in a patient with lipoatrophy, given their potential to increase sc fat. The contribution of body fat changes and metabolic abnormalities to cardiovascular risk and the changing risk profiles of newer antiretroviral regimens are under intense investigation.

Principles of soft tissue augmentation for the aging face

In the quest for the "ideal" soft tissue filler, many diverse products have been developed. The expanding market of available fillers is a testament that no one product will ideally suit all patients or clinicians. In addition, the challenge of satisfying the criteria of an ideal filler has driven researchers to take a variety of development paths. This has resulted in multiple categories to characterize soft tissue fillers. These fillers are categorized according to: (1) filler material, eg, autologous, natural, synthetic; (2) mechanism of action, eg, void filler, neocollagenesis, fibroblast stimulation; (3) patient type and profile, eg, younger versus older patient, rhytids versus "sinking and sagging" skin; or (4) durability of treatment effects, eg, temporary, semi-permanent, or permanent. Although strategies for soft tissue augmentation may be quite diverse, strategies should share a universal goal to address fat redistribution (atrophy and hypertrophy), the primary underlying morphological cause of facial aging. To accomplish this, volumizers are now available that are injected more deeply, resulting in the restoration of supportive structure and foundation. These can be used in combination with other products that are used more superficially for smoothing skin surfaces. As numerous soft tissue fillers enter the market, mechanisms and injection techniques become more divergent, and therefore require that the dermatologist and cosmetic surgeon receive adequate training to use products safely and effectively. This manuscript provides an overview of soft tissue fillers and their proper use.