The treatment of keloids with pneumatic technology: a pilot study

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.

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.

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

Effectiveness of Intralesional Triamcinolone in the Treatment of Keloids in Children

BACKGROUND

The current treatment of keloids includes surgery, intralesional steroids, and radiotherapy, among others. Radiotherapy is not recommended in children due to its effects on growing tissues. Our aim was to study intralesional triamcinilone therapy of keloids in children and analyze the impact of body location, age of the lesion, and etiology of the keloid on clinical response.

METHODS

We conducted a prospective clinical trial with patients 1 to 14 years of age evaluated for keloid treatment. A soft tissue ultrasound was performed to measure the keloid volume, prior to intralesional infiltration with triamcinolone acetonide. A posttreatment ultrasound quantified the volume differences attributed to therapy. For the analysis, Mann-Whitney/Wilcoxon test for paired samples and a multiple regression analysis were performed.

RESULTS

Twenty-one patients with a total of 25 keloids were enrolled, with a median age of 12 years (range 6-14 yrs). The initial lesional volume was 1.25 cc (range 0.2-6.3 cc) and the final volume was 0.2 cc (range 0.0-1.53 cc), corresponding to 82.7% of size reduction (p < 0.001). Regarding the relationships between response and body location, etiology and age of the lesion, the multiple regression analyses obtained p-values of 0.46, 0.16, and 0.87, respectively. One patient failed to improve. Average follow-up was 30 months.

CONCLUSIONS

Triamcinolone acetonide is highly effective for the treatment of pediatric keloids. There is no relationship between clinical response and the factors evaluated, such as lesion location, etiology and age of the keloid.