Complications from Nasolabial Fold Injection of Calcium Hydroxylapatite for Facial Soft-Tissue Augmentation: A Systematic Review and Meta-Analysis

A Structured Approach for Treating Calcium Hydroxylapatite Focal Accumulations

BACKGROUND

Radiesse, a widely utilized calcium hydroxylapatite (CaHA) dermal filler, has shown effectiveness in soft tissue augmentation and regeneration. As with all dermal fillers, the potential for nodules may arise. Understanding the pathogenesis of these nodules and exploring effective treatment methodologies are crucial for optimizing patient outcomes.

OBJECTIVES

A literature search was carried out to identify published literature documenting reversal of CaHA nodules. After identification, a consensus panel developed a structured approach, denoted by levels, for applying such reversal methods.

METHODS

This concise review presents an algorithmic approach to addressing CaHA focal accumulations (noninflammatory nodules) based on invasiveness, cost, and potential risks based on published literature.

RESULTS

Level 0 involves no intervention, relying on natural degradation for asymptomatic nodules. Level 1 interventions utilize mechanical dispersion techniques, including massage and in situ dispersion, which have demonstrated high success rates, cost effectiveness, and minimal invasiveness. Level 2 introduces alternative modalities such as pharmacological treatments with 5-fluorouracil and corticosteroids, lasers, and experimental approaches. Level 3 represents last-resort options, including calcium-chelating agents, manual removal, and surgical excision.

CONCLUSIONS

The article offers a structured approach to managing CaHA focal accumulations.

LEVEL OF EVIDENCE: 4

Efficacy and Safety of Fillers for the Treatment of Nasolabial Folds: A Network meta-Analysis of Randomized Controlled Trials

BACKGROUND

Nasolabial fold formation is increasingly becoming a cause of concern for many people. However, no network meta-analysis has compared the efficacy of different fillers in treating nasolabial folds. This network meta-analysis simultaneously compared the efficacy and safety of various fillers.

METHODS

We included randomized controlled trials (RCTs) that used fillers to treat nasolabial folds. We extracted data of Wrinkle Severity Rating Scale (WSRS), Global Esthetic Improvement Scale (GAIS, investigator) scores, GAIS scores (self-reported) and adverse events.

RESULTS

We included 13 RCTs. WSRS scores at 6 months were higher in patients receiving HA than those receiving poly (L-lactic acid) (mean difference [MD] 0.630, 95% confidence interval [CI] 0.275, 0.985) but significantly lower in patients receiving HA than in those receiving bovine collagen (MD - 0.580, 95% CI - 0.777, - 0.383) and porcine collagen (MD - 0.525, 95% CI - 0.790, - 0.260). Regarding adverse events, HA was significantly less likely to cause nodule formation compared with bovine collagen (RR 0.593, 95% CI 0.438, 0.803).

CONCLUSION

HA is a safe filler for correcting nasolabial folds, and poly (L-lactic acid) showed potential in treating nasolabial folds.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Injectable Hyaluronan-Based Thermoresponsive Hydrogels for Dermatological Applications

Most marketed HA-based dermal fillers use chemical cross-linking to improve mechanical properties and extend their lifetime in vivo; however, stiffer products with higher elasticity require an increased extrusion force for injection in clinical practice. To balance longevity and injectability, we propose a thermosensitive dermal filler, injectable as a low viscosity fluid that undergoes gelation in situ upon injection. To this end, HA was conjugated via a linker to poly(N-isopropylacrylamide) (pNIPAM), a thermosensitive polymer using "green chemistry", with water as the solvent. HA-L-pNIPAM hydrogels showed a comparatively low viscosity (G' was 105.1 and 233 for Candidate1 and Belotero Volume^®, respectively) at room temperature and spontaneously formed a stiffer gel with submicron structure at body temperature. Hydrogel formulations exhibited superior resistance against enzymatic and oxidative degradation and could be administered using a comparatively lower injection force (49 N and >100 N for Candidate 1 and Belotero Volume^®, respectively) with a 32G needle. Formulations were biocompatible (viability of L929 mouse fibroblasts was >100% and ~85% for HA-L-pNIPAM hydrogel aqueous extract and their degradation product, respectively), and offered an extended residence time (up to 72 h) at the injection site. This property could potentially be exploited to develop sustained release drug delivery systems for the management of dermatologic and systemic disorders.

Calcium Orthophosphate (CaPO4)-Based Bioceramics: Preparation, Properties, and Applications

Various types of materials have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A short time later, such synthetic biomaterials were called bioceramics. Bioceramics can be prepared from diverse inorganic substances, but this review is limited to calcium orthophosphate (CaPO4)-based formulations only, due to its chemical similarity to mammalian bones and teeth. During the past 50 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the CaPO4-based implants would remain biologically stable once incorporated into the skeletal structure or whether they would be resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed, and such formulations became an integrated part of the tissue engineering approach. Now, CaPO4-based scaffolds are designed to induce bone formation and vascularization. These scaffolds are usually porous and harbor various biomolecules and/or cells. Therefore, current biomedical applications of CaPO4-based bioceramics include artificial bone grafts, bone augmentations, maxillofacial reconstruction, spinal fusion, and periodontal disease repairs, as well as bone fillers after tumor surgery. Prospective future applications comprise drug delivery and tissue engineering purposes because CaPO4 appear to be promising carriers of growth factors, bioactive peptides, and various types of cells.

Comparative Evaluation of the Effectiveness of Novel Hyaluronic Acid-Polynucleotide Complex Dermal Filler

HA (Hyaluronic acid) filler, the most commonly used dermal filler, causes several side effects. HA-PN (Hyaluronic acid-Polynucleotide), a new composite filler, has excellent biocompatibility and induces tissue regeneration. In this study, we compare the efficacies and safety profiles of these fillers. The characteristics of HA and HA-PN fillers were compared using scanning electron microscopy and rheometry. No morphological difference was noted between the fillers. However, the latter had higher viscosity and elasticity values. The HA-PN filler induced higher cell migration than the HA filler in a wound healing assay. It was also found to stimulate better collagen synthesis in human and mouse fibroblasts. The HA and HA-PN fillers were injected into SKH1 hairless mice to determine changes in their volume for up to 24 weeks. Increased cell migration and collagen synthesis were observed in mice injected with the HA-PN complex filler. Although the safety and durability of the HA and HA-PN fillers were similar, the latter induced a lower transient receptor potential vanilloid 4 expression and caused less stimulation upon injection. In conclusion, HA-PN complex fillers can stimulate fibroblast growth and facilitate volume growth and skin regeneration.