Key importance of compression properties in the biophysical characteristics of hyaluronic acid soft-tissue fillers

Holistic Study Design Following Quality by Design Approach for Fabrication of Hybrid Polymeric Nanoparticulate Based Dry Powders as Carriers for Ciprofloxacin

Resistance to antibiotics such as Ciprofloxacin (CIP) is becoming a critical issue and needs to be addressed globally. CIP is widely used because of manifold uses; however, the long-term therapy poses serious health risks including FDA black box warnings such as tendinitis and peripheral neuropathy. Therefore, nanotechnology-based products can be an effective measure to improve therapeutic outcomes by maintaining the dose at the target site while reducing the dose-dependent toxicity. Biodegradable and biocompatible polymers, Chitosan (CS) and Hyaluronic acid (HA) were used in this work due to their diverse biological characteristics. A simple yet economical ionic gelation method was employed to synthesize nanoparticles with a plexus-like network; nanoplexes, followed by spray-drying to obtain the dry powders to improve stability. Quality by Design (QbD) approach was utilized during the study for robustness and standardization followed by Design of Experiment (DoE) for optimization in a holistic way. The mean particle size of the optimized powder sample was found to be 301.1 nm with a percentage encapsulation efficiency (% EE) of 78.8%. In-vitro dissolution studies corroborated the controlled release of CIP over 48 h. Also, mathematical kinetic modeling was applied to obtain thorough insight into the mechanism of drug release. Moreover, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were presented to be lower in the case of prepared dry powder as compared to CIP, stating that nanotechnology can improve antimicrobial activity.

Intracorporeal evaluation of hyaluronic acid fillers with varied rheological properties and correlations with aesthetic outcomes

BACKGROUND

Understanding the differences in soft tissue filler rheology and how these properties can impact clinical results is a fundamental concepts for any injector. This study aimed to assess the tissue integration characteristics of hyaluronic acid (HA) fillers manufactured with different technologies (Non-Animal Stabilized HA [HA-N] or Optimal Balance Technology [HA-O]) using ultra-high-frequency ultrasound.

METHODS

Twelve female participants with mild-to-moderate midface volume loss and temporal hollowing were enrolled and treated with HA-N and/or HA-O. Participants were seen at five visits (screening/baseline [treatment], and Weeks 1 [optional touch-up], 4, 6, and 8 [follow-up visits]). Ultrasound was used to evaluate the degree of product integration.

RESULTS

On ultrasound, HA-N presented with distinct borders, minimal tissue integration, and a capacity to displace tissues. Conversely, HA-O tended to spread horizontally within the same tissue plane and integrated within tissues. The volumizing capacity of the HA-O fillers was dependent on particle size.

CONCLUSION

HA-N is suited for deep injections in areas such as the upper lateral cheek and under the muscle of the temporal region when a lifting effect is desired; HA-O is best suited for subcutaneous injections, in areas of dynamic movement or for patients with thin skin; and can be injected subcutaneously or supraperiosteally when a volumizing effect is desired.

Exploring facial overfilled syndrome from the perspective of anatomy and the mismatched delivery of fillers

INTRODUCTION

Facial fillers and injectables have transformed the landscape of cosmetic procedures, offering rejuvenation possibilities. However, the emergence of "Facial Overfilled Syndrome (FOS)" presents a concerning trend attributed to excessive filler use and suboptimal injection techniques. Understanding the interplay between facial aging and augmentation techniques is crucial in addressing and preventing FOS.

MATERIAL AND METHODS

Facial overfilled syndrome is characterized by the excessive use of fillers, resulting in a distorted and heavy appearance. It manifests in various forms, including 'flowerhorn' foreheads, 'sunset' eyes, 'chipmunk' cheeks, 'witch' chins, and 'pillow' faces. The syndrome arises from attempts to combat anatomical aging with dramatic filler treatments, causing rapid volume changes and skin tightening. Skeletal structures and soft tissue distribution across different ethnicities play a significant role in FOS development.

RESULTS

Understanding the aging process across facial tissues is essential, as fillers cannot entirely reverse aging manifestations. Tailored assessment and treatment plans should precede filler injections, involving muscle assessment, observation of facial movements during injection, and ultrasound imaging of fat layers. Attention should be given to filler pressure and migration risks, particularly in areas with elevated pressure. Additionally, alternative approaches like energy-based devices and polymer reinforcement of facial ligaments should be considered to minimize filler use. Ethnic variations in facial anatomy require careful consideration to avoid overcorrection.

CONCLUSION

FOS predominantly affects individuals of East Asian descent due to specific facial characteristics. Prevention strategies involve minimizing filler use, addressing underlying bone changes, and considering ethnic and gender differences in facial anatomy. Recent MRI and ultrasound studies challenge the notion of filler breakdown, emphasizing the importance of filler selection and injection techniques. Education, individualized treatments, and a holistic understanding of facial anatomy are key to preventing and managing FOS and ensuring natural and harmonious facial aesthetics.

Simplifying the injector's armamentarium: An international consensus regarding the use of gel science to differentiate hyaluronic acid fillers and guide treatment recommendations

BACKGROUND

The Restylane portfolio of soft tissue fillers spans a wide range of indications, due in part to their complementary manufacturing technologies [non-animal stabilized hyaluronic acid (NASHA) and Optimal Balance Technology (OBT/XpresHAn)]. Using an array of products, injectors can achieve a holistic, natural looking effect for their patients. However, with a wide range of products it may be difficult to choose an optimal combination.

AIM

Simplify and align global use recommendations for NASHA versus OBT products.

METHODS

Two pre-meeting surveys were completed by 11 key opinion leaders with international representation, with the goal of collecting information regarding their current injection practices for various anatomical regions of the face (i.e., temporal region, forehead, tear trough, lateral zygoma, anteromedial cheek, nose, pyriform aperture, nasolabial fold, perioral area, lips, labiomental crease, marionette lines, chin, and jawline). The data collected from these surveys was subsequently discussed in a consensus group meeting involving 11 voting members and 3 nonvoting members.

RESULTS

Top product recommendations were identified for each anatomical area, along with secondary and tertiary recommendations that can also be used under defined circumstances. Recommendations were provided based on a consideration of elements such as patient features (e.g., skin thickness, bone structure), the desired aesthetic outcome, experience of the injector, and the preferred injection technique.

CONCLUSION

A majority consensus regarding the top NASHA versus OBT product choice for each anatomical region of the face was reached. These recommendations represent international agreement regarding the use of Restylane products.

Comprehensive Evaluation of Injectability Attributes in OxiFree™ Dermal Fillers: MaiLi® Product Variants and Clinical Case Reports

Dermal filler injectability is a critical factor for commercial product adoption by medical aesthetic professionals and for successful clinical administration. We have previously reported (in vitro and ex vivo) cross-linked hyaluronic acid (HA)-based dermal filler benchmarking in terms of manual and automated injectability requirements. To further enhance the function-oriented product characterization workflows and the clinical relevance of dermal filler injectability assessments, the aim of this study was to perform in vivo evaluations. Therefore, several variants of the MaiLi® product range (OxiFree™ technology) were characterized in vitro and in vivo in terms of injectability attributes, with a focus on hydrogel system homogeneity and ease of injection. Firstly, standardized in vitro assays were performed in SimSkin® cutaneous equivalents, with variations of the clinical injector, injection site, and injection technique. Then, automated injections in SimSkin® cutaneous equivalents were comparatively performed in a texture analysis setup to obtain fine-granulometry injection force profile results. Finally, five female participants were recruited for the in vivo arm of the study (case reports), with variations of the clinical injector, injection site, and injection technique. Generally, the obtained quantitative force values and injection force profiles were critically appraised from a translational viewpoint, based on discussions around the OxiFree™ manufacturing technology and on in-use specialized clinician feedback. Overall, the present study outlined a notable level of homogeneity across the MaiLi® product range in terms of injectability attributes, as well as consistently high ease of administration by medical aesthetic clinicians.

Comparison of 2 Fillers for Lip Injection-A Randomized-Controlled Clinical Trial Assessed by 3D Imaging

Background

Lip aging is a concern for many, and hyaluronic acid (HA) injections are a popular solution.

Objectives

This study compared 2 different HA gel technologies (OBT and NASHA) for lip augmentation in 20 volunteers.

Methods

Both groups received treatment from the same injector using the same method. Lip volume was measured with a 3D stereophotogrammetry device before, immediately after, and 30 days posttreatment. Patient satisfaction and adverse events were assessed through FACE-Q scales analysis.

Results

The NASHA group showed an immediate volume increase (P = .01), which decreased after 30 days. The OBT group did not show a significant immediate growth (P = .535) but did exhibit a significant increase after 30 days (P = .014). After 30 days, there were no significant volume differences between the groups (P = .802 and P = .999). FACE-Q analysis revealed no significant differences among groups after 30 days.

Conclusions

This study highlights that less cohesive gels may modify faster in dynamic lip areas, emphasizing the importance of selecting products based on their physicochemical and rheological properties. In the context of lip augmentation with HA, it is important not to consider immediate aesthetic changes as definitive results, as volume changes may persist and develop over time after the treatment.

Level of Evidence 2

Strengthening the Key Features of Volumizing Fillers: Projection Capacity and Long-Term Persistence

Volumizing fillers aim to create or restore facial volume in fat layers. To provide strong tissue lifting and long-term persistence, gels are generally designed with stiff properties, characterized by a high storage modulus (G'). However, clinical evidence shows a discrepancy between high G' and good lifting capacities, especially after skin tension has been exerted on the gel. To better explore the in vivo behavior of a gel, we first evaluated the elastic moduli of five commercial volumizers (RHA4, JUVVOL, RESVOL, RESLYFT, and BELVOL) in dynamic compression mode, E'. We further developed a Projection Index score based on the rheological assessment of creep in compression to mimic skin tension-induced stress relaxation (flattening). Finally, the ability of a gel to resist enzymatic degradation was analyzed with a multidose approach. Despite similar clinical indications, volumizers exhibited distinct behaviors. RHA4 and BELVOL showed the highest E' values (resistance to strain), RHA4, JUVVOL, and RESVOL exhibited the greatest projection capacities, while JUVVOL and RHA4 offered the largest persistence to enzymatic degradation. In this article, we introduce the use of the Projection Index to efficiently assess the ability of a gel to lift tissues, thus increasing preclinical models' efficiency and reducing the need for animal studies.

NIR-degradable and biocompatible hydrogels derived from hyaluronic acid and coumarin for drug delivery and bio-imaging

In this work, bioorthogonal and photodegradable hydrogels derived from norbornene (Nb) functionalized hyaluronic acid and a water soluble coumarin-based cross-linker possessing terminal tetrazine (Tz) groups, were developed for NIR-responsive release of doxorubicin (DOX). The inverse electron demand Diels-Alder cross-linking reaction between Nb and Tz functionalities formed the hydrogels at physiological conditions, whereas N₂ gas liberated during the reaction created pores in the hydrogels. The gelation time ranges (about 5-20 min) and the viscoelastic behavior (G' ~ 346-1380 Pa) demonstrated that the resulting hydrogels were injectable and possessed tunable mechanical properties. Moreover, hydrogels released the encapsulated DOX upon NIR irradiation, owing to the NIR-responsive cleavage of coumarin-ester, and consequently, induced anti-tumor activity in BT-20 cancer cells. Additionally, the hydrogels could be excited at various wavelengths of the visible spectrum and can emit green to red fluorescence, demonstrating their simultaneous photo-responsive drug release and bio-imaging applications.

Time- and Dose-Dependent Effects of Hyaluronidase on the Degradation of Different Hyaluronan-Based Fillers In Vitro

BACKGROUND

Hyaluronidase (HYAL) is regarded as the standard for the management of complications associated with hyaluronan (HA)-based fillers. Therefore, the understanding of interactions of HA fillers and HYAL is essential.

METHODS

Nine different commercially available HA fillers (Belotero, Juvéderm, and Restylane) with varying degrees of cross-linking were used for the analysis. Fluorescently dyed HA fillers were individually incubated with varying doses of HYAL [bovine HYAL (Hylase "Dessau"; Riemser Pharma, Germany); 5, 10, and 20 U/mL] or sodium chloride and monitored by time-lapse microscopy. HA filler degradation was assessed as a decrease in fluorescence intensity of HA filler plus HYAL compared to HA filler plus control, quantified by computerized image analysis.

RESULTS

HA fillers show significant differences in their reaction to HYAL. Levels of degradation of HA fillers are positively correlated with increasing concentrations of HYAL. At the highest concentration of HYAL (20 U/mL), all fillers except one (Belotero Volume) reached a significant level of degradation at 5 to 9 hours.

CONCLUSIONS

In this study, the authors show that most HA fillers can be dissolved by HYAL in a dose- and time-dependent manner. Of note, the fillers' technology and degree of cross-linking seem to exert stronger effects on the degradability by HYAL as compared to the concentration of HA.

CLINICAL RELEVANCE STATEMENT

The authors' in vitro analyses support clinical recommendations stating that in the case of a vascular filler incident, HYAL should be applied early and at significant doses ("Time is skin!").

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Contouring Plus: A Comprehensive Approach of the Lower Third of the Face with Calcium Hydroxylapatite and Hyaluronic Acid

A well-defined jawline is aesthetically pleasing, so that rejuvenation of the jawline is becoming part of routine aesthetic practice. Restoring balance to the lower face without surgical intervention requires a multiple treatment approach, among which the minimally invasive injectables play a central role. Nevertheless, amidst the plethora of different injectable products available, choosing the option that best suits the patient's need can be a challenge. A panel of experts sought to describe herein 4 clinical cases, illustrating the Contouring Plus technique, which provides a practical guidance for lower third assessment, choice of products, and treatment execution, especially among hyaluronic acid and calcium hydroxylapatite, aiming for immediate, as well as mid-to-long-term results.

New Directions in Aesthetic Medicine: A Novel and Hybrid Filler Based on Hyaluronic Acid and Lactose Modified Chitosan

Fillers based on crosslinked hyaluronic acid (HA) are becoming increasingly important in the field of aesthetic medicine, for example for treating wrinkles or for volumizing purposes. However, crosslinking agents are usually associated with toxicity and adverse reactions. The aim of this study is the development of an innovative technology to manufacture high performance HA-based fillers using minimal amounts of crosslinking agent. In this work, new fillers based on HA, functionalized with different amounts of 1,4-butanediol diglycidyl ether (BDDE) (degree of modification ranging between 3.5% and 8.8%) and formulated with a lactose modified chitosan (CTL), were investigated. The relative quantities of these polymeric building blocks in the formulations were 20-25 and 5 mg/mL for HA and CTL, respectively. Due to its cationic nature, CTL could interact with the anionic HA and enhance the elastic properties of the filler. Fillers manufactured with this novel technology (HACL-CTL) were characterized and compared with several fillers available in the market. In particular, resistance against hyaluronidase, swelling, cohesivity and rheological properties were investigated. Cohesivity, resistance to hydrolysis and swelling of HACL-CTL were comparable to commercial products. However, HACL-CTL fillers showed excellent elastic performance that reached 94% of elasticity in response to shear stresses. Surprisingly, these fillers also showed a resistance to compression higher than that of currently marketed products, making them very promising for their lifting effect.

Design of an elastic porous injectable biomaterial for tissue regeneration and volume retention

Soft tissue reconstruction currently relies on two main approaches, one involving the implantation of external biomaterials and the second one exploiting surgical autologous tissue displacement. While both methods have different advantages and disadvantages, successful long-term solutions for soft tissue repair are still limited. Specifically, volume retention over time and local tissue regeneration are the main challenges in the field. In this study the performance of a recently developed elastic porous injectable (EPI) biomaterial based on crosslinked carboxymethylcellulose is analyzed. Nearly quantitative volumetric stability, with over 90% volume retention at 6 months, is observed, and the pore space of the material is effectively colonized with autologous fibrovascular tissue. A comparative analysis with hyaluronic acid and collagen-based clinical reference materials is also performed. Mechanical stability, evidenced by a low-strain elastic storage modulus (G') approaching 1kPa and a yield strain of several tens of percent, is required for volume retention in-vivo. Macroporosity, along with in-vivo persistence of at least several months, is instead needed for successful host tissue colonization. This study demonstrates the importance of understanding material design criteria and defines the biomaterial requirements for volume retention and tissue colonization in soft tissue regeneration. STATEMENT OF SIGNIFICANCE: We present the design of an elastic, porous, injectable (EPI) scaffold suspension capable of inducing a precisely defined, stable volume of autologous connective tissue in situ. It combines volume stability and vascularized tissue induction capacity known from bulk scaffolds with the ease of injection in shear yielding materials. By comparative study with a series of clinically established biomaterials including a wound healing matrix and dermal fillers, we establish design rules regarding rheological and compressive mechanical properties as well as degradation characteristics that rationally underpin the volume stability and tissue induction in a high-performance biomaterial. These design rules should allow to streamline the development of new colonizable injectables.

Consensus on the Use of Hyaluronic Acid Fillers from the Cohesive Polydensified Matrix Range: Best Practice in Specific Facial Indications

Background

As the treatment indications for the Cohesive Polydensified Matrix^® hyaluronic acid (CPM-HA) portfolio continue to expand and diversify, injectors new to the range or those who are expanding the treatments they offer may be unsure of the optimal product and injection technique for specific facial areas. Each product in the CPM-HA portfolio has been intentionally designed to provide the best physical properties for a specific indication and target tissue. This document has been developed to provide a comprehensive, one-stop reference for clinicians using the portfolio.

Methods

An international panel of experts in the field of aesthetic medicine convened to develop guidelines on effective and safe injection technique when performing treatments with the CPM-HA range of soft-tissue fillers.

Results

Consensus members considered treatment indications in the upper, middle and lower face. Landmark deficiencies and anatomical considerations are described for each indication and consensus recommendations provided on the optimal product, injection depth and treatment technique. This is supplemented by the experts advice on avoidance of complications. Throughout, an evidence-based approach to selection of products and injection techniques is provided. The result is a fully tailored approach to a range of indications covering the full portfolio of CPM-HA products, including the newest addition for skin revitalization.

Conclusion

The recommendations in this consensus document are provided to assist clinicians in the selection of CPM-HA products, administration techniques and depths of injection with the aim of providing seamless and natural treatment results, enhanced safety and patient satisfaction.

Comparative Physicochemical Analysis among 1,4-Butanediol Diglycidyl Ether Cross-Linked Hyaluronic Acid Dermal Fillers

(1) Background: Injectable hyaluronic acid (HA) dermal fillers are used in several chirurgical practices and in aesthetic medicine. HA filler stability can be enhanced through different cross-linking technologies; one of the most frequently cross-linker used is 1,4-butanediol diglycidyl ether (BDDE), also present in the HA-BDDE dermal filler family of the company Matex Lab S.p.A. (Brindisi, Italy). Our overview is focused on their characterization, drawing a correlation between matrix structure, rheological and physicochemical properties related to their cross-linking technologies. (2) Methods: Four different injectable HA hydrogels were characterized through optical microscopic examination and rheological behavior investigation. (3) Results: The cross-linked HA dermal fillers showed a fibrous "spiderweb-like" matrix structure and an elastic and solid-like profile. (4) Conclusions: The comparative analysis represents a preliminary characterization of these injectable medical devices in order to identify their best field of application.

Advanced Concepts in Rheology for the Evaluation of Hyaluronic Acid-Based Soft Tissue Fillers

BACKGROUND

Crosslinked hyaluronic acid (HA)-based soft tissue fillers possess unique viscoelastic properties intended to match specific product indications. Manufacturing has an impact on HA chain integrity and on filler properties.

OBJECTIVE

This study introduces 2 new rheological parameters to evaluate the macroscopic characteristics of fillers.

METHODS AND MATERIALS

A library of reference commercialized HA fillers was selected to cover the full spectrum of product indications. Gels were assessed in terms of size of released HA fragments as a readout of gel integrity, degree of modification, cohesivity, and rheological properties.

RESULTS

The elastic modulus G' often used to characterize fillers was shown not to follow macroscopic mechanical properties. To improve the mechanical characterization of fillers, Strength and Stretch scores were developed and tested. The Strength score defined the ability of a filler to sustain constant viscoelasticity over a wide range of constraints and represented the filler mechanical resilience. The Stretch score measured the propensity of a filler to deform in view to improve implant adaptation to facial animation for natural-looking results.

CONCLUSION

Strength and Stretch scores sorted rheological parameters to macroscopic cohesivity assays more accurately than G' and may thus help predict the gel behavior once implanted and submitted to facial dynamics.

Spreading Pattern and Tissue Response to Hyaluronic Acid Gel Injections in the Subcutis: Ultrasound Videos, Ultrasound Measurements, and Histology

Background

Despite the popularity of hyaluronic acid (HA) filler treatments, few publications focus on their effects on adipose tissue.

Objectives

The authors assessed the deposition pattern in the subcutis of injected HA, the tissue response at short and intermediate term, and the effects of remodeling the filler by strong finger pressure immediately after the treatment.

Methods

Two brands, specifically developed by the industry for deep injection, were compared. The gels were injected subcutaneously in 5 candidates for abdominoplasty or breast reduction, in the area of excision, 6 to 98 days before surgery. Ultrasound measurements and films were compared with postoperative histological findings. Tissue response was scored semi-quantitatively.

Results

Real-time ultrasound showed a slightly different deposition pattern of the 2 brands. Histologically, both were present in large pools of the same magnitude and looked the same. Linear retrograde injection sometimes resulted in a globular deposit due to elastic recoil of septae. After remodeling and over time, HA deposits became difficult to detect by ultrasound. Firm remodeling of the tissue immediately after injection or time had no significant effect on filler spread or tissue response. Except for 1 zone of granuloma formation, tolerance for both fillers was good.

Conclusions

HA deposition in adipose tissue occurs in much larger pools than in the dermis. Ultrasound examination is useful during and immediately after the injection but less reliable after filler remodeling or over time. Filler deposition can be less precise, and reshaping by finger pressure can have less effect than expected.

Level of Evidence: 4

Improvements in Skin Quality Biological Markers in Skin Explants Using Hyaluronic Acid Filler VYC-12L

Hyaluronic acid (HA), both crosslinked and uncrosslinked, is used clinically to treat fine lines and provides additional improvements in skin quality attributes. The purpose of this study was to assess potential early differences in the expression of biological markers of skin quality in living human skin explants injected with uncrosslinked and crosslinked HA gels.

Methods

Living human skin explants injected with VYC-12L or noncrosslinked HA with mannitol (HYD) and noninjected controls were assessed via microscopy, histology, and immunohistochemistry on days 3 and/or 8 for biological markers of elasticity (collagen density, elastin, fibrillin-1) and hydration [aquaporin-3, acidic glycosaminoglycans (GAGs), HA]. Hydration was also assessed via a corneometer probe on days 0, 1, 2, and 8.

Results

On day 3 versus controls, VYC-12L moderately increased collagen density in the upper reticular dermis and clearly increased fibrillin-1 expression, with slight increases persisting on day 8. Increases with HYD were smaller and did not persist on day 8. Both VYC-12L and HYD increased aquaporin-3 expression and GAG content on days 3 and 8, but VYC-12L produced greater GAG increases in the reticular dermis. Day 8 instrument-assessed hydration increased by 49% and 22% for VYC-12L and HYD, respectively. Elastin expression in oxytalan and elaunin fibers was unchanged. Upper-dermal HA reductions suggested HA injection-induced hyaluronidase expression.

Conclusion

VYC-12L produced greater, more lasting improvements in biological markers of skin quality than HYD.

Dynamics of hyaluronic acid fillers formulated to maintain natural facial expression

BACKGROUND

Subjects seeking facial rejuvenation want the results to appear natural. Currently, however, there is no consensus definition of, or assessment scale for, "naturalness."

AIMS

This open-label pilot study explored evaluation techniques and criteria to assess naturalness of facial movement and expression following optimal bilateral correction of moderate-to-severe nasolabial folds and marionette lines with soft-tissue hyaluronic acid fillers formulated with XpresHAn Technology™.

METHODS

Primary efficacy was investigator assessed naturalness of dynamic expressions using baseline and Day 42 posttreatment 2D video. Other evaluations included investigator assessed naturalness using static images, wrinkle severity, investigator and subject Global Aesthetic Improvement Scale assessments, and subject satisfaction.

RESULTS

Thirty Caucasian females (41-65 years) received either Restylane^® Refyne, Restylane^® Defyne or both. Naturalness of dynamic expressions was at least maintained in all subjects. Naturalness of static expressions was not negatively affected in most subjects (96.7%). For dynamic expressions, 83.3% of subjects showed enhanced attractiveness, younger appearance and maintained naturalness.

CONCLUSIONS

Overall, nasolabial folds and marionette lines improved significantly based on severity and Global Aesthetic Improvement Scale scores, with high subject satisfaction and favorable safety profile. Based on subject satisfaction and investigator assessments, using highly flexible hyaluronic acid dermal fillers did not compromise naturalness of lower facial expressions while achieving the desired improvements in attractiveness and youthfulness. The preliminary results obtained in this pilot study suggest that dynamic and static assessments of facial animation may aid the evaluation of natural outcomes in facial rejuvenation procedures.

Rheologic and Physicochemical Properties Used to Differentiate Injectable Hyaluronic Acid Filler Products

BACKGROUND

Injectable hyaluronic acid fillers are routinely used for correction of soft-tissue volume loss and facial rejuvenation. Product differentiation has primarily been based on the rheologic parameter known as elastic modulus (G'), although other physicochemical properties are being explored to characterize potential product performance. As clinical data regarding product performance are lacking, the practical experience of injectors provides a valuable bridge in the knowledge gap between product rheologic data and product use.

METHODS

Rheologic and physicochemical measurements (swelling factor and cohesion) were collected for 18 products. To observe the impact of G' and hyaluronic acid concentration on swelling factor and cohesion, proportional relationships were evaluated. Contributing authors were queried regarding their G'-based selection of products when considering skin quality, degree of correction, injection depth, and anatomical location.

RESULTS

Relationships were observable between G' and swelling factor and G' and cohesion only when limited to products manufactured by the same crosslinking technology and the same concentration. No relationship between isolated hyaluronic acid concentration and swelling factor or cohesion was apparent. Although rheological parameters and the assumptions of ex vivo data translating to in vivo performance are oftentimes not completely aligned, in the clinical experience of the authors, in general, higher G' products are better suited for thicker skin and deeper injection planes, whereas lower G' products are better for more superficial planes, although exceptions to these trends are also made based on technical experience.

CONCLUSIONS

While rheologic and physicochemical characteristics can vary widely between products and the methods and measurements of these parameters are often difficult to correlate, G' represents a useful and consistent parameter for product differentiation. Understanding how to select products based on G' is valuable knowledge for customizing injection plans and contributes to an optimal aesthetic outcome.

Cohesive Polydensified Matrix® cross-linked hyaluronic acid volumizing gel: a magnetic resonance imaging and computed tomography study

Background

Concentrated hyaluronic acid (HA) gels with a high degree of cross-linking such as Cohesive Polydensified Matrix^® (CPM) HA have been designed for long-term facial volume restoration.

Objective

To determine the behavior and longevity of CPM HA gel, a case series of subjects underwent magnetic resonance imaging (MRI) or computed tomography (CT) scans several years after their initial treatment.

Methods

Six subjects, three from the initial CPM HA Conformité Européenne registration study and three from private practice who had received prior injection of CPM HA for facial volumizing indications agreed to undergo an MRI or CT scan at intervals ranging from 1 to 4 years after the initial treatment. The amount of HA gel originally injected was compared with the amount estimated from volumetric analysis of the MRI and CT scans. The scans were also examined for the signs of any abscess or granuloma formation and to determine the behavior of the HA gel over time.

Results

CT and MRI imaging of the six study subjects indicated CPM HA gel persisted for 2–4 years after only a single treatment. In some patients, product was evident in deeper facial fat compartments than originally injected suggesting some diffusion of product had occurred. There was no MRI or CT evidence of abscess or granuloma formation.

Conclusion

Our findings indicate that CPM HA volumizing gel has substantial longevity when injected subcutaneously or in deep soft tissues.

Cohesive Polydensified Matrix® hyaluronic acid volumizer injected for cheek augmentation has additional positive effect on nasolabial folds

Purpose

Cohesive Polydensified Matrix^® hyaluronic acid (CPM-HA) volumizer has been used successfully for several years to reverse biometric volume loss during facial aging. This observational study explored the additive effect on nasolabial folds when CPM-HA volumizer is injected into the neighboring cheek area.

Patients and methods

In this open-label, prospective, postmarketing noninterventional study, 18 adult patients seeking esthetic enhancement of the lateral cheek hollows and cheekbone area were injected with CPM-HA volumizer integrated with lidocaine (CPM-HA-VL) in the upper or lower cheek area. Safety and performance of CPM-HA-VL up to 12 months after injection with follow-up visits at week 4 and month 3, 6, and 12 were assessed. The primary endpoint was improvement of cheek fullness on the validated Merz Aesthetics Scales. Additionally, changes in nasolabial folds were quantified using a phaseshift rapid in vivo measurement of skin optical three-dimensional (3D) in vivo measurement device.

Results

Patients (94.4% female, median age 52 years, age range 39–69 years) were injected with a mean volume of 2.5±1.1 mL CPM-HA-VL per side. Immediately after injection, mean severity for upper and lower cheek fullness assessed on the validated MAS improved from 2.5±0.6 and 2.8±0.5, respectively, to 1.0±0.0, and remained unchanged through month 12. Improvement in relation to baseline was attested on the Global Aesthetics Improvement Scale for all assessments. Compared with baseline, the following assessments offered a statistical significance in the reduction of wrinkle depth of nasolabial folds (maximum depth reduction by 30.4% at 3 months) according to optical 3D in vivo measurements. Pain during injection was minimal and abated within 30 minutes. Treatment was well tolerated and led to great patient satisfaction.

Conclusion

CPM-HA-VL injected into the upper and lower cheeks led to long-lasting satisfactory cosmetic results in cheek augmentation as well as in reducing depth of nasolabial folds adjacent to the injection site.

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.

Minimal recovery time needed to return to social engagement following nasolabial fold correction with hyaluronic acid fillers produced with XpresHAn technology

INTRODUCTION

The appeal of hyaluronic acid fillers for facial soft tissue augmentation is attributable to both an immediate aesthetic effect and relatively short recovery time. Although recovery time is an important posttreatment variable, as it impacts comfort with appearance and perceived treatment benefit, it is not routinely evaluated. Natural-looking aesthetic outcomes are also a primary concern for many patients.

MATERIALS AND METHODS

A single-center, noncomparative study evaluated the time (in hours) until subjects return to social engagement (RtSE) following correction of moderate and severe nasolabial folds (NLFs) with R_R (Restylane^® Refyne)^® and R_D (Restylane Defyne), respectively. Twenty subjects (aged 35-57 years) who received bilateral NLF correction documented their RtSE and injection-related events posttreatment. Treatment efficacy was evaluated by improvements in Wrinkle Severity Rating Scale (WSRS) and subject satisfaction questionnaire at days 14 and 30, and by Global Aesthetic Improvement Scale (GAIS) at day 30. Safety was evaluated by injection-related events and treatment-emergent adverse events.

RESULTS

Fifty percent of subjects reported RtSE within 2 hours posttreatment. WSRS for the R_R group improved significantly from baseline at day 14 (-1.45±0.42) and day 30 (-1.68±0.46) (P<0.001), respectively. WSRS for the R_D group improved significantly from baseline at day 14 (-2.22±0.44) and day 30 (-2.50±0.50) (P<0.004), respectively. All GAIS improvements were clinically significant at day 30. The majority of injection-related events were mild or moderate. Two subjects experienced 3 related treatment-emergent adverse events; 1 R_R subject experienced severe bruising, and 1 R_D subject experienced severe erythema and mild telangiectasia. Subject satisfaction was high regarding aesthetic outcomes and natural-looking results.

CONCLUSION

Optimal correction of moderate NLFs with R_R and severe NLFs with R_D involved minimal time to RtSE for most subjects. Treatments that significantly improved WSRS and GAIS, were generally well-tolerated, and provided natural-looking aesthetic outcomes.

Ultrasound and Histologic Examination after Subcutaneous Injection of Two Volumizing Hyaluronic Acid Fillers: A Preliminary Study

Supplemental Digital Content is available in the text.

Background:

This study examined the influence of hyaluronic acid (HA) crosslinking technology on the ultrasound and histologic behavior of HA fillers designed for subcutaneous injection.

Methods:

One subject received subcutaneous injections of 0.25 ml Cohesive Polydensified Matrix (CPM) and Vycross volumizing HA in tissue scheduled for abdominoplasty by bolus and retrograde fanning techniques. Ultrasound analyses were performed on days 0 and 8 and histologic analyses on days 0 and 21 after injection. A series of simple rheologic tests was also performed.

Results:

Day 0 ultrasound images after bolus injection showed CPM and Vycross as hypoechogenic papules in the hypodermis. CPM appeared little changed after gentle massage, whereas Vycross appeared more hyperechogenic and diminished in size. Ultrasound images at day 8 were similar. On day 0, both gels appeared less hypoechogenic after retrograde fanning than after bolus injection. Vycross was interspersed with hyperechogenic areas (fibrous septa from the fat network structure) and unlike CPM became almost completely invisible after gentle massage. On day 8, CPM appeared as a hypoechogenic pool and Vycross as a long, thin rod. Day 0 histologic findings confirmed ultrasound results. Day 21 CPM histologic findings showed a discrete inflammatory reaction along the injection row after retrograde fanning. Vycross had a more pronounced inflammatory reaction, particularly after retrograde fanning, with macrophages and giant cells surrounding the implant. Rheologic tests showed CPM to have greater cohesivity and resistance to traction forces than Vycross.

Conclusions:

CPM HA volumizer appears to maintain greater tissue integrity than Vycross after subcutaneous injection with less inflammatory activity.

[Hyaluronic acid rheology: Basics and clinical applications in facial rejuvenation]

Hyaluronic acid (HA) is the most widely used dermal filler to treat facial volume deficits and winkles specially for facial rejuvenation. Depending on various areas of the face, filler is exposed to two different forces (shear deformation and compression/stretching forces) resulting from intrinsec and external mechanical stress. The purpose of this technical note is to explain how rheology, which is the study of the flow and deformation of matter under strains, can be used in our clinical practice of facial volumization with fillers. Indeed, comprehension of the rheological properties of HA has become essential in selection of dermal filler targeted to the area of the face. Viscosity, elasticity and cohesivity are the main three properties to be taken into consideration in this selection. Aesthetic physicians and surgeons have to familiarize with those basics in order to select the HA with the right rheological properties to achieve a natural-looking and long-lasting outcome.