Clinical results of skin remodeling using a novel pneumatic technology

Low Molecular Weight Hyaluronic Acid Added to Six Specific Amino Acids in the Treatment of Striae Alba (SA): An Observational Study

Striae distensae or stretch marks are a common complaint among women and can be distressing. The present study aimed to assess the efficacy of a mixture of low molecular weight hyaluronic acid and six amino acids when applied with a specific intradermal injection technique known as intra-mural fluid technique. A clinical study was carried out in 32 patients (with a dropout rate by 9.4%) with striae distensae alba (SA) in one or more of the following anatomical areas: breast, abdomen, inner thigh, trochanteric area, gluteal area, posterior supra-iliac area, and lumbar area. Product efficacy was assessed by the investigator using the Global Aesthetic Improvement Scale, while a Likert scale was used to evaluate to score the treatment tolerability and a QoL stretch marks questionnaire was used to investigate the patients' self-body image. The treatment was effective in improving the appearance of SA fifteen days after the second treatment and 6 months after the first treatment (and after a total of 4 treatments). The product efficacy and tolerability were also perceived by the patients during each treatment session. Our results suggest that the test treatment is a valid treatment option to decrease the appearance of SA. LEVEL OF EVIDENCE IV: 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 https://www.springer.com/00266.

Facial Skin Rejuvenation Using Poly-dl-Lactic Acid Injected With a Laser-Generated Needle-Free Microjet Injector

BACKGROUND

A laser-induced needle-free microjet injector was developed for rapid, high-speed drug delivery of microliters into the skin.

OBJECTIVE

This study evaluated the clinical rejuvenation effect of repeated dermal injections of the collagen simulator poly-dl-lactic acid (PDLA) using a laser-induced needle-free microjet injector.

METHODS

Five PDLA injection sessions using a laser-induced needle-free microjet injector were conducted in patients concerned about aging skin. Facial uplifting, darkness, redness, roughness, pore size, subjective satisfaction, and side effects were evaluated before each session and 4 weeks after treatment completion. Histological evaluation was also performed with immunohistochemical staining of collagen and elastic fibers.

RESULTS

The clinical results of 27 female patients were evaluated. The treatment resulted in a noticeable skin surface uplifting (0.711 ± 0.42 mm) and significant improvements in darkness (p = .013), redness (p = .009), and roughness (p = .036), with no significant difference in the pore size (p = .770). Patients were reported being satisfied with the overall therapeutic effects, despite mild and tolerable adverse effects. Histological findings revealed growth and thickening of collagen and elastic fibers, with marked increase in collagen I and III levels.

CONCLUSION

Repeated dermal injections of PDLA using a laser-induced microjet injector offer excellent drug delivery, achieving high efficacy in skin rejuvenation, patient satisfaction, and safety.

Home-Use Hyaluronic Acid Jet Injectors: Unreliable and Unsafe

BACKGROUND

Needle-free hyaluronic acid (HA) jet injectors are gaining popularity for rejuvenation treatment. The devices are widely available online and are used for self-injection or in beauty salons by nonphysicians. However, little is known about their performance and safety.

OBJECTIVE

To explore the injection efficiency and cutaneous biodistribution patterns administered with home-use compared with medical jet injectors and to assess safety aspects.

MATERIALS AND METHODS

The authors injected HA into ex vivo human skin with 4 home-use and 2 medical injectors. The intracutaneous dose of HA was calculated, and the cutaneous biodistribution of HA was assessed using a 3-dimensional Fluorescent Imaging Cryomicrotome System (3D-FICS). Safety aspects were evaluated based on the presence of a manual, CE (conformité européenne) mark, and sterility.

RESULTS

The intracutaneous dose delivered by the home-use injectors was markedly lower compared with the medical injectors. 3D imaging for home-use injectors showed superficial epidermal distribution with low distribution volumes. For medical injectors, volumes were substantially larger and mainly middermal. All evaluated safety aspects were lacking.

CONCLUSION

Results of this study suggest that the specific combinations of home-use injectors and HA used in this study are unreliable and unsafe, which casts doubts on the performance of these treatments in general.

Experimental investigation of the optimal driving pressure for a larger-volume controllable jet injection system

Jet injection technology has become the alternative drug delivery method of conventional needle-based injection due to its obvious advantages. In order to meet the demand for larger volume injection, the pneumatic jet injection systems have efficiently administrated vaccine up to 1 mL in human. Our recent study has also demonstrated that controlling the driving pressure enabled the pneumatic jet injection system to deliver larger volumes of drugs to target sites at desired rates and times. This work continues to explore the optimal two-phase driving pressure combination with better injection efficiency for typical larger-volume (1.0 mL) jet injection with controllable pneumatic jet injection system. Under the combination of a first phase driving pressure of 1.00 MPa and a second phase driving pressure ranging from 0.25 to 0.90 MPa, dynamic characteristics, dispersion characteristics and pharmacokinetic characteristics of this controllable jet injection system were quantitatively analyzed. In all experiments, it was confirmed that the optimal driving pressure combination of 1.0 mL ejection volume was close to (1.00-0.50) MPa. That is, the injection velocities of 151.85 m/s and 102.01 m/s for the first and second phase respectively facilitated better injection performance with a controlled release of 1.0 mL ejection volume. This strategy is practical for facilitating the clinical application of large-volume controllable jet injection systems.

Efficacy and safety of needle-free jet injector-assisted intralesional treatments in dermatology-a systematic review

Needle-free jet injectors are used for the intralesional treatment of various dermatological indications. However, a systematic review that evaluates the efficacy and safety of these treatments has not been published. The objectives of this study are to evaluate the efficacy and safety of needle-free jet injections for dermatological indications and to provide evidence-based treatment recommendations. An electronic literature search was conducted in April 2022. Two reviewers independently selected studies based on predefined criteria and performed a methodological quality assessment using the Cochrane Collaborations risk-of-bias 2.0 assessment tool and Newcastle-Ottawa Scale. Thirty-seven articles were included, involving 1911 participants. Dermatological indications included scars, alopecia areata, hyperhidrosis, nail diseases, non-melanoma skin cancer, common warts, local anesthesia, and aesthetic indications. Keloids and other types of scars (hypertrophic, atrophic, and burn scars) were investigated most frequently (n = 7). The included studies reported favorable efficacy and safety outcomes for intralesional jet injector-assisted treatment with triamcinolone acetonide/hexacetonide, 5-fluorouracil, bleomycin, or hyaluronic acid. Two high-quality studies showed good efficacy and tolerability of intralesional jet injections with a combination of 5-fluorouracil and triamcinolone acetonide in hypertrophic scars and with saline in boxcar and rolling acne scars. No serious adverse reactions and good tolerability were reported in the included studies. Overall, the methodological quality of the included studies was low. Limited evidence suggests that needle-free jet injector-assisted intralesional treatment is efficacious and safe for hypertrophic and atrophic acne scars. More well-powered RCTs investigating the efficacy and safety of jet injector treatment in dermatology are warranted to make further evidence-based recommendations.

The Air Toxin Technique: Introduction and Analysis of Effect using a Photo Imaging System

BACKGROUND

As an alternative to other approaches to facial rejuvenation, the air toxin technique (dermal injection of air with micro-doses of botulinum toxin) is a promising method. We aimed to describe this novel technique and assess the overall safety and efficacy of the air toxin technique in facial rejuvenation.

MATERIALS AND METHODS

A retrospective chart review was performed on cases treated with the air toxin technique. A total of 47 Korean patients underwent a single treatment session. Treatment efficacy was assessed objectively with serial VISIA® (Canfield Scientific, NJ, USA) skin analysis data and subjectively based on the patients' assessment scores at week 12.

RESULTS

A significant improvement in Wrinkle (p < 0.001), UV spot (p < 0.001), and Porphyrin (p = 0.005) were objectively seen at 12-weeks follow-up. Patients noted improvement in the categories Wrinkle (p < 0.01), Redness (p = 0.029), Texture (p < 0.001), Dilated pore (p < 0.001), and Lifting (p < 0.001) at week 12 compared to baseline. No major adverse event was reported.

CONCLUSIONS

Our data show that the Air toxin technique is efficacious in facial rejuvenation as shown by improved skin analysis parameters and patient assessment scores. Notably, there was some discrepancy between the objective and subjective parameters of improvement.

Dorsal Hand Rejuvenation: A Systematic Review of the Literature

BACKGROUND

Dorsal hand appearance undergoes changes with aging. Grading systems have been designed to provide numerical scores to dorsal hand appearance. Various modalities have been utilized to improve the aesthetic appearance and rejuvenate the dorsal hand.

METHODS

The MEDLINE database was searched for articles investigating dorsal hand rejuvenation. Studies were grouped by method including fat grafting, injectable filler, laser/light-based treatments and miscellaneous treatments. Treatment protocols and outcomes were compiled along with patient information and complications.

RESULTS

Forty-six articles were identified for inclusion. This included 9 studies of fat grafting procedures, 20 studies of injectable filler, 10 studies of laser/light-based treatments and 7 miscellaneous. Most studies showed overall good results with high patient satisfaction. Satisfaction rates were lower in laser/light-based treatments compared with the other modalities. The average patient age for included studies ranged from 41.5 to 69. Across all studies, 96.8% of patients were female and 3.2% male.

CONCLUSIONS

Procedures for dorsal hand rejuvenation in the literature include procedures to address volume atrophy and superficial wrinkling. These procedures are overall safe with most studies reporting no complications or only mild adverse events. With high satisfaction rates and anecdotal reports of increasing patient interest, these procedures represent a developing area in aesthetic surgery likely to continue increasing in popularity.

LEVEL OF EVIDENCE III

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 .

Mechanism and clinical applications of needle-free injectors in dermatology: Literature review

BACKGROUND

Needle-free jet injectors are devices that deliver drugs using a high-speed jet without a needle. Recent studies have significantly increased our understanding of the mechanisms of needle-free jet injectors, and technical advancements have broadened the scope of application of the device.

AIMS

We aimed to provide an up-to-date review of previous literature regarding the mechanism of action and clinical applications of needle-free jet injectors in dermatology field.

METHODS

We conducted a PUBMED search for studies on needle-free jet injectors using the following parameters: "Pneumatic injector" OR "needleless injector" OR "needle-free injector" OR "jet injector." Among 191 results, 72 articles focusing on their mechanisms of action, cutaneous delivery patterns, and clinical applications in dermatology were selected for review.

RESULTS

Significant clinical evidence has been published confirming the potential of needle-free jet injectors in treating various dermatologic conditions. In particular, these devices have the potential to be used in various skin remodeling treatment, especially in skin rejuvenation procedures by injecting various esthetic materials.

CONCLUSION

As proven by accumulated experience, the applications of NFJIs are not restricted to vaccine or insulin delivery in dermatology field. However, this literature review shows that until now, there are no clinical guidelines that standardize the optimal parameters when using NFJIs on various clinical settings. Therefore, further studies should be performed in order to investigate the full potential of these devices in dermatology, to ensure safe and effective outcomes in clinical practice.

High-velocity pneumatic injection of non-crosslinked hyaluronic acid for skin regeneration and scar remodeling: A retrospective analysis of 115 patients

BACKGROUND

Pneumatic-assisted high velocity jet injections are an alternative method for intradermal delivery of hyaluronic acid (HA) and demonstrated efficacy in dermal thickening and scar remodeling with minimal side effects.

AIMS

We aimed to investigate the clinical efficacy comparing non-crosslinked HA (NCL-HA) and crosslinked HA (CL-HA) for aesthetic skin concerns.

METHODS

We retrospectively analyzed charts of 115 patients treated with jet injected NCL-HA and CL-HA for skin rejuvenation, age-related laxity and rhytidosis, hypertrophic and acne scars and striae. Global Aesthetic Improvement Scale (GAIS) and the 5-grade patient satisfaction scale were used for assessment of the treatment efficacy at the 3-month follow-up. Efficacy was separately analyzed between patients receiving NCL-HA vs. CL-HA. Longevity of treatment effect was measured by the time to voluntary return for repeat treatment.

RESULTS

An average of 2.8 treatments was completed per patient with a low incidence of side effects including bruises (7%) and temporary local edema (1%). Patients were highly-satisfied with the treatment results in all categories with the average satisfaction scores of 3.68 (NCL-HA) and 3.76 (CL-HA). An average GAIS score of 1.7 ("much improved") was calculated for neck, décolleté and perioral areas. An overall GAIS score averaged as 1.78 (NCL-HA) and 1.6 (CL-HA). Longevity of the effect averaged 13.1 months for NCL-HA and 13.2 months for CL-HA groups.

CONCLUSION

Our retrospective data showed similar significant improvement of all aesthetic skin concerns in 115 subjects treated with either NCL-HA or CL-HA delivered intradermally by a high velocity jet-injector device with minimal downtime, pain or side-effects.

In vivo evaluation of novel particle-free polycaprolactone fillers for safety, degradation, and neocollagenesis in a rat model

Dermal fillers have become popular due to the increased demand for skin rejuvenation products. Polycaprolactone (PCL), a newly developed bioresorbable medical polymer, has emerged as a durable and safe dermal filler. However, available PCL fillers cause irritation; carrier gels can coagulate PCL particles, block the injection needle, and cause nonhomogeneity of particle suspensions that could be responsible for the observed side effects. To relieve pain, premixing PCL filler with lidocaine. However, this formulation changes the property of the CMC portion of the PCL filler, and possibly results in an uneven suspension of the PCL particles. Hence, a particle-free PCL homogeneously solubilized in water was developed to overcome these limitations. This study aimed to assess the in vivo safety, biodegradability, and neocollagenesis ability of a novel PCL filler, DLMR01 using a rat model. Fillers were characterized after injecting a vehicle control or DLMR01 using a digital camera, folliscope, and a three-dimensional profiling system. Biopsy was performed to evaluate biocompatibility and neocollagenesis. Skin elasticity was measured using a Cutometer. DLMR01 caused no needle occlusion by particle aggregation or laborious injectability. Filler nodules dispersed to surrounding tissues within 6 hours without further granuloma formation. Histological inspection revealed no tissue residual material or foreign body reaction during the 12-week test period. DLMR01 increased dermal thickness, collagen regeneration, and skin elasticity. In conclusion, this study demonstrates the potential of DLMR01 for dermal rejuvenation in a rat model.

Biochemical and physical actions of hyaluronic acid delivered by intradermal jet injection route

Administration of exogenous hyaluronic acid (HA) by liquid jet injection is considered as a beneficial therapy for dermatology conditions. This paper reviews variety of the factors which would optimize the clinical output of hyaluronic acid in this treatment modality. A pneumatically accelerated jet penetrates the epidermis and spherically spreads micro-droplets of HA in the dermis without significant damage to the tissue and blood vessels. Kinetic energy of the jet activates two parallel mechanisms of action-mechanical and biological-which act synergistically to initiate and augment the regenerative effect. Jet-induced micro-trauma stimulates collagen synthesis and tissue repair without inflammation. Aside from the biophysical stimulation of dermal fibroblast, the biomolecular properties of exogenous HA provide excellent clinical results for skin atrophy, remodeling of dermal scarring, and reverse formation of fibrotic tissue. The effect is mediated by HA-specific cell receptors and depends on molecular weight and the rheological properties of HA polymer. Skin mechanical properties play a key role in predicting HA dispersion patterns. Tolerability and safety of the treatment approach are determined by the jet's physical impact on the tissue and/or by the safety profile of the injected material. Although pneumatic jet delivery of a hyaluronic acid has a limited use in clinical practice, this treatment approach has a strong potential for extended implementation in esthetic dermatology. The synergistic mechanism has significant advantages of predictable and rapid clinical outcomes with a low discomfort. Additional well-designed investigations are required for establishing a scientific foundation and guidelines for this treatment modality.

Potentials for implementing pressure-controlled jet injection in management of keloids with intralesional 5FU and corticosteroids

BACKGROUND

Needle-free jet injection implements kinetic energy of liquid jet for transcutaneous delivery of drugs into soft tissues. Combination therapy of intralesional 5-fluorouracil and triamcinolone offers efficacious treatment for keloids with a reduced adverse effect of the drug monotherapy. This study evaluates safety and efficacy of the drug combination administered to keloid scars via intralesional jet injections.

METHODS

A retrospective analysis of the keloid treatments was performed. Efficacy was assessed by reviewing pre- and post-treatment scores of the Vancouver Scar Scale (VSS) and Patient and Observer Scar Assessment Scale (POSAS) and by comparing baseline and photographs taken 3 months after the treatments. Safety and tolerability were collected and analyzed.

RESULTS

Twenty-one subjects (M/F = 11/10) with 39 keloids received the treatments. Treatments were well-tolerated by all patients at mean injection pain of 2.0 ± 1.0 per Numeric Pain Rating Scale (NPRS). Self-resolved lesion ulceration was observed in 4 patients. Post-treatment evaluation demonstrated a 53% decrease in total VSS score (P < 0.05) and in all sub-categories. Mean patient score of POSAS decreased in the color, stiffness, thickness, and irregularity components. Pain and pruritus lessened by 69% and 79% (P < 0.05 in both), respectively, among the patients with complaints prior to the treatment. Independent reviewers reported an average 51%-75% reduction in keloids.

CONCLUSIONS

Improved appearance of keloids and symptomatic relief was achieved by intralesional administration of combined 5-fluorouracil and corticosteroid through the high-pressure jet injections. The synergy between the drug combination and the jet physical impact provided clinical effect.

Electronic Pneumatic Injection-Assisted Dermal Drug Delivery Visualized by Ex Vivo Confocal Microscopy

Background and Objectives

Electronic pneumatic injection (EPI) is a technique for dermal drug delivery, which is increasingly being used in clinical practice. However, only few studies have been reported on cutaneous drug distribution and related clinical endpoints. We aimed to visualize the immediate cutaneous drug distribution, changes in skin architecture, and related clinical endpoint of EPI.

Study Design/Materials and Methods

Acridine orange (AO) solution was administered to ex vivo porcine skin by EPI at pressure levels from 4 to 6 bar with a fixed injection volume of 50 µl and nozzle size of 200 µm. Immediate cutaneous distribution was visualized using ex vivo confocal microscopy (EVCM). Changes in skin architecture were visualized using both EVCM and hematoxylin and eosin‐stained cryosections.

Results

The defined immediate endpoint was a clinically visible papule formation on the skin. The pressure threshold to consistently induce a papule was 4 bar, achieving delivery of AO to the deep dermis (2319 µm axial and 5944 µm lateral distribution). Increasing the pressure level to 6 bar did not lead to significant differences in axial and lateral dispersion (P = 0.842, P = 0.905; respectively). A distinctively hemispherical distribution pattern was identified. Disruption of skin architecture occurred independently of pressure level, and consisted of subepidermal clefts, dermal vacuoles, and fragmented collagen.

Conclusions

This is the first study to relate a reproducible clinical endpoint to EPI‐assisted immediate drug delivery using EVCM. An EPI‐induced skin papule indicates dermal drug delivery throughout all layers of the dermis, independent of pressure level settings. Lasers Surg. Med. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC

Effect of geometrical parameters on the fluid dynamics of air-powered needle-free jet injectors

Needle-free jet injectors are non-invasive systems having intradermal drug delivery capabilities. At present, they revolutionize the next phase of drug delivery and therapeutic applications in the medical industry. An efficiently designed injection chamber can reduce the energy consumption required to achieve the maximum penetration depth in skin tissue. In this study, the authors explored the effect of various geometrical parameters using a computational fluid dynamics tool. Peak stagnation pressure during the initial phase of the injection procedure was considered as the quantifier for comparison because of its proportional relationship with the initial penetration depth during the injection process. Peak stagnation pressure indicates the maximum energy transformation that could happen between the microjet and skin tissues for an injection procedure. The results of this study indicated a tradeoff that exists between the attainable density and velocity of the microjet on the skin surface with variation in nozzle diameter; the optimum nozzle diameter was found to be within 200-250 μm under the present conditions. The authors also observed a discrepancy in the peak stagnation pressure value for lower filling ratios with variation in chamber diameter; hence, filling ratio of at least 50% was recommended for such systems. Furthermore, a 150% increase in the peak stagnation pressure was obtained with an angle of entry of 10°. In general, this study could provide valuable insights into the effect of geometrical parameters in the fluid dynamics characteristics of propelled microjets from the nozzle of a needle-free jet injector. Such information could be useful for the design of a mechanically driven needle-free jet injector having limited control over the energizing mechanism.

Needle-free pneumatic injection device; histologic assessment using a rat model and parameter comparison in predicting collagen synthesis degree

BACKGROUND

Needle-free pneumatic injections have been recently introduced to the field of dermatology to inject such substances as hyaluronic acid. However, data on the influence of various pneumatic injection parameters on collagen synthesis are lacking.

OBJECTIVE

Compare the effect of diameter, pressure, and volume of a pneumatic injection jet on collagen synthesis and fluid dispersion pattern using a rat model. Investigate if the total work force of the injection jet is useful in predicting the degree of collagen synthesis.

MATERIALS AND METHODS

We injected fluid with 1 mg/ml of hyaluronic concentration to adult rats. Different injection pressures and volumes were tested using devices with nozzles of different diameters. Collagen synthesis areas were then measured, and statistical analyses were performed.

RESULTS

The area of collagen fibers increased for up to two months. The injection pressure and volume did not correlate with the degree of collagen synthesis. The nozzle diameter showed a significant after two and four weeks of injection. The total work force correlated with collagen synthesis 2, 4, and 8 weeks post-injection. (P = 0.043, 0.027, and 0.000, respectively).

CONCLUSION

Collagen formation is more prominent 2 months post-hyaluronic acid injection than after 1 month when using a needle-free pneumatic injection device. The total work force, which is affected by both the nozzle diameter and injection pressure, can be helpful in predicting the degree of collagen synthesis. Lasers Surg. Med. 51:278-285, 2019. © 2019 Wiley Periodicals, Inc.

Effect of a Facial Muscle Exercise Device on Facial Rejuvenation

BACKGROUND

The efficacy of facial muscle exercises (FMEs) for facial rejuvenation is controversial. In the majority of previous studies, nonquantitative assessment tools were used to assess the benefits of FMEs.

OBJECTIVES

This study examined the effectiveness of FMEs using a Pao (MTG, Nagoya, Japan) device to quantify facial rejuvenation.

METHODS

Fifty females were asked to perform FMEs using a Pao device for 30 seconds twice a day for 8 weeks. Facial muscle thickness and cross-sectional area were measured sonographically. Facial surface distance, surface area, and volumes were determined using a laser scanning system before and after FME. Facial muscle thickness, cross-sectional area, midfacial surface distances, jawline surface distance, and lower facial surface area and volume were compared bilaterally before and after FME using a paired Student t test.

RESULTS

The cross-sectional areas of the zygomaticus major and digastric muscles increased significantly (right: P < 0.001, left: P = 0.015), while the midfacial surface distances in the middle (right: P = 0.005, left: P = 0.047) and lower (right: P = 0.028, left: P = 0.019) planes as well as the jawline surface distances (right: P = 0.004, left: P = 0.003) decreased significantly after FME using the Pao device. The lower facial surface areas (right: P = 0.005, left: P = 0.006) and volumes (right: P = 0.001, left: P = 0.002) were also significantly reduced after FME using the Pao device.

CONCLUSIONS

FME using the Pao device can increase facial muscle thickness and cross-sectional area, thus contributing to facial rejuvenation.

LEVEL OF EVIDENCE 4

Drug delivery systems and materials for wound healing applications

Chronic, non-healing wounds place a significant burden on patients and healthcare systems, resulting in impaired mobility, limb amputation, or even death. Chronic wounds result from a disruption in the highly orchestrated cascade of events involved in wound closure. Significant advances in our understanding of the pathophysiology of chronic wounds have resulted in the development of drugs designed to target different aspects of the impaired processes. However, the hostility of the wound environment rich in degradative enzymes and its elevated pH, combined with differences in the time scales of different physiological processes involved in tissue regeneration require the use of effective drug delivery systems. In this review, we will first discuss the pathophysiology of chronic wounds and then the materials used for engineering drug delivery systems. Different passive and active drug delivery systems used in wound care will be reviewed. In addition, the architecture of the delivery platform and its ability to modulate drug delivery are discussed. Emerging technologies and the opportunities for engineering more effective wound care devices are also highlighted.

Assessment Tools for Facial Rejuvenation Treatment: A Review

BACKGROUND

In the field of cosmetic medicine, patient satisfaction is an important and common indicator used to measure the efficacy of the treatment. However, it is insufficient to prove objectively that the benefit of the specific factors involved in the cosmetic outcomes. The practitioner should be aware of these assessment tools, in particular in case of demanding or litigious patients.

OBJECTIVE

The aim of this review was to establish a list and discuss the subjective and objective methods used to assess facial aesthetic rejuvenation treatments.

METHODS

A systematic literature search was performed using the Pubmed search engine. Studies published over the last 5 years, i.e. between January 2010 and January 2015 were considered for review. The following keywords were used: "aesthetic treatment", "facial rejuvenation", and "subjective evaluation" or "objective evaluation".

RESULTS

Of the 446 articles identified by the search strategy, 47 articles focused specifically on facial rejuvenation and on the efficacy of aesthetic medical treatments were retrieved for review. Thirty-seven articles used quantitative methods to assess aesthetic treatment outcomes and only 12 used subjective methods. The different assessment methods were listed according to the tools used and treatment indications.

CONCLUSION

This review will help in choosing adequate methods to assess facial rejuvenation medical treatment. It is important to combine these tools adequately to improve the assessment. There is no current consensus on assess facial rejuvenation treatments but we noted that objective assessment methods seem helpful.

NO LEVEL ASSIGNED

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 .

Needle-free jet injection of hyaluronic acid improves skin remodeling in a mouse model

PURPOSE

The purpose of this study was to improve methods of jet injection using a mouse model. We investigated the mechanism of action, efficacy, and safety of the pneumatic device using injection of hyaluronic acid (HA) solution into a mouse model.

METHODS

We evaluated the efficacy and safety of an INNOJECTOR™ pneumatic device that pneumatically accelerates a jet of HA solution under high pressure into the dermis of mouse skin. We examined the treatment effects using skin hybrid model jet dispersion experiments, photographic images, microscopy, and histological analyses.

RESULTS

Use of the INNOJECTOR™ successfully increased dermal thickness and collagen synthesis in our mouse model. Jet dispersion experiments were performed using agarose gels and a polyacrylamide gel model to understand the dependence of jet penetration on jet power. The mechanisms by which pneumatic injection using HA solution exerts its effects may involve increased dermal thickening, triggering of a wound healing process, and activation of vimentin and collagen synthesis.

CONCLUSIONS

Collagen synthesis and increased dermal thickening were successfully achieved in our mouse model using the INNOJECTOR™. Pneumatic injection of HA under high pressure provides a safe and effective method for improving the appearance of mouse skin. Our findings indicate that use of the INNOJECTOR™ may induce efficient collagen remodeling with subsequent marked dermal layer thickening by targeting vimentin.

Investigating skin penetration depth and shape following needle-free injection at different pressures: A cadaveric study

BACKGROUND AND OBJECTIVES

The effectiveness of needle-free injection devices in neocollagenesis for treating extended skin planes is an area of active research. It is anticipated that needle-free injection systems will not only be used to inject vaccines or insulin, but will also greatly aid skin rejuvenation when used to inject aesthetic materials such as hyaluronic acid, botulinum toxin, and placental extracts. There has not been any specific research to date examining how materials penetrate the skin when a needle-free injection device is used. In this study, we investigated how material infiltrates the skin when it is injected into a cadaver using a needle-free device.

STUDY DESIGN/MATERIALS AND METHODS

Using a needle-free injector (INNOJECTOR™; Amore Pacific, Seoul, Korea), 0.2 ml of 5% methylene blue (MB) or latex was injected into cheeks of human cadavers. The device has a nozzle diameter of 100 µm and produces a jet with velocity of 180 m/s. This jet penetrates the skin and delivers medicine intradermally via liquid propelled by compressed gasses. Materials were injected at pressures of 6 or 8.5 bars, and the injection areas were excised after the procedure. The excised areas were observed visually and with a phototrichogram to investigate the size, infiltration depth, and shape of the hole created on the skin. A small part of the area that was excised was magnified and stained with H&E (×40) for histological examination.

RESULTS

We characterized the shape, size, and depth of skin infiltration following injection of 5% MB or latex into cadaver cheeks using a needle-free injection device at various pressure settings. Under visual inspection, the injection at 6 bars created semi-circle-shaped hole that penetrated half the depth of the excised tissue, while injection at 8.5 bars created a cylinder-shaped hole that spanned the entire depth of the excised tissue. More specific measurements were collected using phototrichogram imaging. The shape of the injection entry point was consistently spherical regardless of the amount of pressure used. When injecting 5% MB at 6 bars, the depth of infiltration reached 2.323 mm, while that at 8.5 bars reached 8.906 mm. The area of the hole created by the 5% MB injection was 0.797 mm(2) at 6 bars and 0.242 mm(2) at 8.5 bars. Latex injections reached a depth of 3.480 mm at 6 bars and 7.558 mm at 8.5 bars, and the areas were measured at 1.043 mm(2) (6 bars) and 0.355 mm(2) (8.5 bars). Histological examination showed that the injection penetrated as deep as the superficial musculoaponeurotic system at 6 bars and the masseter muscle at 8.5 bars.

CONCLUSION

When injecting material into the skin using a pneumatic needle-free injector, higher-pressure injections result in a hole with smaller area than lower-pressure injections. The depth and shape of skin penetration vary according to the amount of pressure applied. For materials of low density and viscosity, there is a greater difference in penetration depth according to the degree of pressure. Lasers Surg. Med. 48:624-628, 2016. © 2016 Wiley Periodicals, Inc.

A prospective multicenter pilot study of the safety and efficacy of microfocused ultrasound with visualization for improving lines and wrinkles of the décolleté

BACKGROUND

A previous pilot study demonstrated microfocused ultrasound with visualization (MFU-V) to lift and tighten the décolleté produced significant and durable aesthetic improvements.

OBJECTIVE

To further evaluate the safety and effectiveness of MFU-V for improving lines and wrinkles of the décolleté in a larger patient population.

MATERIALS AND METHODS

Healthy women with moderate-to-severe décolleté skin lines and wrinkles were enrolled. After obtaining digital images, MFU-V was administered using 3 transducers emitting ultrasound at frequencies of 4 MHz and a focal depth of 4.5 mm, 7 MHz/3.0 mm, and 10 MHz/1.5 mm. During the procedure, 280 lines of discrete thermal coagulative points 25 mm long and 2 to 3 mm apart were applied to the treatment area. Additional imaging for masked assessments and live assessments were completed at 90 and 180 days.

RESULTS

Among the evaluable subjects, 77 (66.4%) demonstrated aesthetic improvement at 180 days based on blinded assessments. Approximately, 75% and 65% of treated subjects demonstrated some degree of improvement at 90 and 180 days, respectively, and most were satisfied with treatment outcomes. Adverse events were generally mild.

CONCLUSION

A single MFU-V treatment provided significant aesthetic improvement for moderate-to-severe décolleté lines and wrinkles for at least the 180-day duration of the study.

Long-term effectiveness and safety of small gel particle hyaluronic acid for hand rejuvenation

BACKGROUND

Fillers to reverse the effects of fat atrophy can help restore the hands' youthful appearance.

OBJECTIVE

To evaluate the effectiveness and safety of small gel particle hyaluronic acid (SGP-HA) for hand rejuvenation through 1 year.

MATERIALS AND METHODS

A prospective open-label study recruited adults with moderate to severe vascular, bony, and tendon prominence. After a topical anesthetic was applied, SGP-HA (maximum dose of 4.0 mL) was injected into the dorsum using a threading technique and distributed by massage.

RESULTS

There were 16 patients with a mean ± SD age of 60.1 ± 5.3. Two weeks after treatment, vascular, tendon, and bony prominence and skin turgor were improved by 60.9%, 65.2%, 73.7%, and 26.3%, respectively. Substantial or complete global aesthetic improvement was rated in 75% of patients by investigators and in 56% by self-report; 81% of patients were satisfied or very satisfied. Five needed a touch-up (maximum 1.0 mL/hand). Improvements were largely maintained at 6 months, with 85% patient satisfaction, and assessments approached pretreatment levels at 1 year, with 50% patient satisfaction. One patient reported itching on one hand, which was judged to be unrelated to treatment.

CONCLUSION

SGP-HA produced lasting improvements in aging hands and was safe and well tolerated.