Treatment with synchronized radiofrequency and facial muscle stimulation: Histologic analysis of human skin for changes in collagen and elastin fibers.

BACKGROUND: Skin's exposure to intrinsic and extrinsic factors causes age-related changes, leading to a lower amount of dermal collagen and elastin. AIM: This study investigated the effects of a novel facial muscle stimulation technology combined with radiofrequency (RF) heating on dermal collagen and elastin content for the treatment of facial wrinkles and skin laxity. METHODS: The active group subjects (N = 6) received four 20-min facial treatments with simultaneous RF and facial muscle stimulation, once weekly. The control subject (N = 1) was untreated. Skin biopsies obtained at baseline, 1-month and 3-month follow-up were evaluated histologically to determine collagen and elastin fibers content. A group of independent aestheticians evaluated facial skin appearance and wrinkle severity. Patient safety was followed. RESULTS: In the active group, collagen-occupied area reached 11.91 ± 1.80 × 106 µm2 (+25.32%, p < 0.05) and 12.35 ± 1.44 × 105 µm2 (+30.00%, p < 0.05) at 1-month and 3-month follow-up visits. Elastin-occupied area at 1-month and 3-month follow-up was 1.64 ± 0.14 × 105 µm2 (+67.23%, p < 0.05), and 1.99 ± 0.21 × 105 µm2 (+102.80%, p < 0.05). In the control group, there was no significant difference (p > 0.05) in collagen and elastin fibers. Active group wrinkle scores decreased from 5 (moderate, class II) to 3 (mild, class I). All subjects, except the control, improved in appearance posttreatment. No adverse events or side effects occurred. CONCLUSION: Decreased dermal collagen and elastin levels contributes to a gradual decline in skin elasticity, leading to facial wrinkles and unfirm skin. Study results showed noticeable improvement in facial appearance and increased dermal collagen and elastin content subsequent to simultaneous, noninvasive RF, and facial muscle stimulation treatments.

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.

Is multiple wavelength diode laser for facial contouring safe?

The multiple wavelength diode laser (MWDL) is a sophisticated device designed to target deeper skin layers by emitting various wavelengths. Its unique feature is the ability to deliver heat to specific depths within the tissue using different wavelengths while simultaneously cooling the skin surface. Recent research by Choi et al. suggests that wavelengths of 755 and 810 nm can induce carbonization in hair follicles, while the 1064 nm wavelength penetrates deeper into tissues. MWDL has been proposed for fat redistribution in aging, but concerns have been raised regarding ocular safety and potential tissue damage, particularly when used near the eyes. Studies have shown ocular injuries during cosmetic laser procedures, emphasizing the need for robust ocular protection and safety protocols. Additionally, there are reports of internal ischemic necrosis and burns, highlighting the importance of precise energy settings and parameter management. While MWDL shows promise, further research and comprehensive guidelines are needed to ensure safe and effective usage in clinical practice.

Microneedling versus microcoring: A review of percutaneous collagen induction for the face and neck.

BACKGROUND: Microneedling (MN) and microcoring (MCT) are both methods used for percutaneous collagen induction. This minimally invasive technique involves creating controlled damage in cutaneous tissue to induce neocollagenesis and neoelastogenesis. MN utilizes solid microneedles and is commonly combined with radiofrequency (RF) to add thermal energy, while MCT involves hollow microneedles capable of removing excess tissue without inducing scar formation. AIMS: The purpose of this review was to summarize recent literature for MN and MCT, with the goal of assisting clinical decision making regarding the use of these technologies. METHODS: PubMed search was conducted for relevant articles published within the last 10 years. Scoping literature review was then performed with pertinent findings reported. RESULTS: Existing literature investigating MCT is sparse. Limited data on in vivo, human effects of this technology exist. Two out of 14 studies in this review pertained to MCT. CONCLUSION: Additional high-powered clinical studies are needed to guide future cosmetic treatments with MN and MCT.

Efficacy and safety of combined microneedling therapy for androgenic alopecia: A systematic review and meta-analysis of randomized clinical trials.

OBJECTIVE: To provide dermatologists with more clinical experience in treating androgenetic alopecia, we evaluated the effect and safety of combined microneedling therapy for androgenetic alopecia. METHODS: Studies on combined microneedling for hair loss were comprehensively searched by us in PubMed, Excerpta Medica Database, and the Cochrane Library Database. The literature search spanned the period from 2012 to 2022. Inclusion and exclusion criteria were developed, and the literature was screened according to this criteria. The Cochrane Risk of Bias Tool was used to assess the quality of the studies. The researcher applied Revman 5.3 and Stata 15.1 software to analyze the data after extracting information from the data. RESULTS: Finally, 13 RCTs involving 696 AGA patients were included to compare the clinical effectiveness and adverse events of combined MN therapy with single MN therapy or single drug therapy for AGA. The results of meta-analysis showed as follows: (1) Hair density and diameter changes: The combined MN group was significantly better than any single treatment group, and the differences were statistically significant (MD = 13.36, 95% CI = [8.55, 18.16], Z = 5.45, p < 0.00001; MD = 18.11, 95% CI = [13.70, 22.52], Z = 8.04, p < 0.00001; MD = 13.36, 95% CI = [8.55, 18.16], Z = 5.45, p < 0.00001; MD = 2.50, 95% CI = [0.99, 4.02], Z = 3.23, p = 0.001); (2) the evaluation of satisfaction for efficacy: The doctor satisfaction rating of the combined MN group was significantly higher than that of any single treatment group, with statistical difference (RR = 2.03, 95% CI = [1.62, 2.53], Z = 6.24, p < 0.00001). The difference between the two groups regarding patients satisfaction was not significant (RR = 3.44, 95% CI = [0.67, 17.59], Z = 1.49, p = 0.14). (3) Safety: There was no statistical difference in the incidence of adverse reactions between combination therapy and monotherapy (RR = 0.83, 95% CI = [0.62, 1.12], Z = 1.22, p = 0.22). CONCLUSION: The combined MN group showed statistically significant improvement in hair density and diameter, and good safety compared with monotherapy.

Procedimentos estéticos com ênfase na queda capilar / Aesthetic procedures with emphasis on hair loss / Procedimientos estéticos con énfasis en la caída del cabello

A beleza está diretamente ligada ao aspecto dos cabelos, em todos os tempos e todas as culturas. O cabelo ao longo da vida é sujeito a vários tipos de mudanças, sejam elas naturais ou artificiais, conduzidas por uma vontade de mudar, muitas vezes, seja por representar uma nova fase, como também é símbolo de autocuidado, vaidade, sucesso, possuem significativa importância na aparência e autoestima das pessoas e, por isso, a queda capilar pode atingir a qualidade de vida do indivíduo. Neste sentido, o objetivo deste estudo foi avaliar procedimentos estéticos minimamente invasivos e não cirúrgicos com ênfase na queda capilar. Para tanto, foi realizada uma revisão bibliográfica integrativa, de caráter descritivo nas principais bases de dados em saúde: SciELO, Google Acadêmico, PubMed e livros de medicina, nos idiomas português, inglês e espanhol, considerando o período de 2007 a 2022. De acordo com o último censo da Sociedade Brasileira de Dermatologia, a queixa de alopecia está entre as dez mais frequentes nos consultórios dermatológicos. As doenças capilares mais importantes estão divididas em dois grupos, as cicatriciais quando a perda de cabelo é acompanhada por cicatrizes resultando em calvície permanente, e as não cicatriciais onde a calvície não é permanente levando a diminuição e o afinamento gradual do cabelo. A alopecia não cicatricial é a mais frequente e as mais comuns entre elas são a alopecia androgenética e o eflúvio telógeno. Muitos pacientes procuram tratamento para melhorar a aparência e a autoestima, que podem estar relacionados a quadros de ansiedade e depressão. Esses tratamentos devem ser individualizados, onde se deve avaliar as características individuais de cada paciente. Os tratamentos capilares estéticos podem contribuir de forma significativa para a redução da baixa autoestima, contribuindo para recuperação da autoconfiança através do crescimento capilar proporcionado pela estética. Sendo assim, conclui-se que os resultados coletados na revisão de literatura foram satisfatórios, de forma onde mostra que os medicamentos, suplementos e tratamentos estéticos na queda capilar vem evoluindo cada vez mais. Contudo, mais estudos acerca do assunto são necessários.

Beauty is directly linked to the appearance of hair, in all times and all cultures. Hair throughout life is subject to various types of changes, whether natural or artificial, driven by a desire to change, often because it represents a new phase, as it is also a symbol of self-care, vanity, success, they have significant importance in people's appearance and self-esteem and, therefore, hair loss can affect the individual's quality of life. In this sense, the objective of this study was to evaluate minimally invasive and non- surgical aesthetic procedures with an emphasis on hair loss. To this end, an integrative bibliographic review was carried out, of a descriptive nature, in the main health databases: SciELO, Google Scholar, PubMed and medical books, in Portuguese, English and Spanish, considering the period from 2007 to 2022. According to the latest census by the Brazilian Society of Dermatology, the complaint of alopecia is among the ten most frequent complaints in dermatological offices. The most important hair diseases are divided into two groups, scarring when hair loss is accompanied by scars resulting in permanent baldness, and non-scarring where baldness is not permanent leading to gradual thinning and thinning of the hair. Non-scarring alopecia is the most frequent and the most common among them are androgenetic alopecia and telogen effluvium. Many patients seek treatment to improve their appearance and self-esteem, which may be related to anxiety and depression. These treatments must be individualized, where the individual characteristics of each patient must be evaluated. Aesthetic hair treatments can contribute significantly to reducing low self-esteem, contributing to the recovery of self-confidence through hair growth provided by aesthetics. Therefore, it is concluded that the results collected in the literature review were satisfactory, in a way that shows that medicines, supplements and aesthetic treatments in hair loss have been evolving more and more. However, more studies on the subject are needed.

La belleza está directamente ligada al aspecto del cabello, en todos los tiempos y en todas las culturas. El cabello a lo largo de la vida está sujeto a diversos tipos de cambios, ya sean naturales o artificiales, impulsados por un deseo de cambio, a menudo, ya sea para representar una nueva etapa, como también es un símbolo de auto- cuidado, la vanidad, el éxito, tienen una importancia significativa en la apariencia y la autoestima de las personas y, por lo tanto, la pérdida del cabello puede afectar la calidad de vida del individuo. En este sentido, el objetivo de este estudio fue evaluar los procedimientos estéticos mínimamente invasivos y no quirúrgicos con énfasis en la pérdida de cabello. Para ello, se realizó una revisión bibliográfica descriptiva integradora en las principales bases de datos de salud: SciELO, Google Scholar, PubMed y libros de medicina, en portugués, inglés y español, considerando el período de 2007 a 2022. Según el último censo de la Sociedad Brasileña de Dermatología, la queja de alopecia está entre las diez más frecuentes en las consultas de dermatología. Las enfermedades capilares más importantes se dividen en dos grupos, las cicatriciales, cuando la caída del cabello va acompañada de cicatrices que dan lugar a una calvicie permanente, y las no cicatriciales, cuando la calvicie no es permanente, dando lugar a un adelgazamiento y reducción gradual del cabello. Las alopecias no cicatriciales son las más frecuentes y entre ellas destacan la alopecia androgenética y el efluvio telógeno. Muchos pacientes buscan tratamiento para mejorar su aspecto y autoestima, que pueden estar relacionados con la ansiedad y la depresión. Estos tratamientos deben ser individualizados, donde se deben evaluar las características individuales de cada paciente. Los tratamientos capilares estéticos pueden contribuir significativamente a la reducción de la baja autoestima, contribuyendo a la recuperación de la confianza en uno mismo gracias al crecimiento del cabello que proporciona la estética. Por lo tanto, se concluye que los resultados recogidos en la revisión bibliográfica fueron satisfactorios, mostrando que los medicamentos, suplementos y tratamientos estéticos para la caída del cabello están evolucionando cada vez más. Sin embargo, son necesarios más estudios sobre el tema.

Home-based devices in dermatology: a systematic review of safety and efficacy.

There is increasing demand for home-based devices for the treatment of dermatologic conditions and cosmesis. Commercially available devices include intense pulsed light, laser diodes, radiofrequency, light-emitting diodes, and ultraviolet B phototherapy. The objective of this report is to evaluate the current evidence regarding the efficacy and safety of home-based devices for the treatment of skin conditions. A systematic search of PubMed, Embase, and Cinahl was conducted on November 9, 2020 using PRISMA guidelines. Original research articles that investigated the efficacy and safety of home-based devices for dermatologic use were included. Bibliographies were screened for additional relevant articles. Strength of evidence was graded using the Oxford Centre for Evidence-Based Medicine guidelines. Clinical recommendations were then made based on the quality of the existing literature. After review, 37 clinical trials were included-19 were randomized controlled trials, 16 were case series, and 2 were non-randomized controlled trials. Ultimately, from our analysis, we recommend the home-based use of intense pulsed light for hair removal, laser diodes for androgenic alopecia, low power radiofrequency for rhytides and wrinkles, and light-emitting diodes for acne vulgaris. Trials investigating ultraviolet B phototherapy for psoriasis revealed mixed evidence for home treatments compared to clinic treatments. All devices had favorable safety profiles with few significant adverse events. Limitations to our review include a limited number of randomized controlled trials as well as a lack of data on the long-term efficacy and safety of each device.

Automated Microneedling Versus Fractional CO2 Laser in Treatment of Traumatic Scars: A Clinical and Histochemical Study.

BACKGROUND/OBJECTIVES: Microneedling has shown satisfactory effects in scar rejuvenation. Comparisons of its results with fractional laser are limited. This study aims to compare the efficacy and safety of automated microneedling versus fractional carbon dioxide (CO2) laser in treatment of traumatic scars on clinical and histochemical bases. MATERIALS AND METHODS: Thirty patients with traumatic facial scars were randomized to treatment with 4 monthly sessions of either automated microneedling or fractional CO2 laser. Assessment of scars was performed at baseline and 3 months after the last treatment session, clinically by the modified Vancouver Scar Scale (mVSS) and histochemically by quantitative assessment of collagen and elastic fibers. RESULTS: Both groups showed improvement in mVSS, collagen, and elastin contents after treatment. Percentage improvement of collagen and elastin content was higher after treatment by a laser compared with microneedling, in case of the collagen content. Percentage increase in the collagen content after treatment was higher in atrophic scars of the laser group than those of the microneedling group. CONCLUSION: In this small study, microneedling was as safe as fractional CO2 laser for rejuvenation of traumatic scars with comparable clinical effects. Fractional CO2 laser is more powerful in stimulating neocollagenesis. Automated microneedling is effective for treatment of hypertrophic scars.

Safety Profile for Microneedling: A Systematic Review.

BACKGROUND: Microneedling is a minimally invasive procedure that stimulates collagen and elastin proliferation. It is used in the treatment of various skin pathologies, that is, scarring, photodamage, and hair loss; however, its safety profile has yet to be comprehensively reviewed. OBJECTIVE: This review will discuss the reported side effects of microneedling in the current literature and delineate factors that increase the risk of complications. MATERIALS AND METHODS: A literature search in August 2019 was conducted using the PubMed database to identify studies reporting adverse events (AEs) after microneedling therapy. RESULTS: Eighty-five articles were included in this systematic review. The most common reported AEs are transient procedural events that are expected postprocedure lasting up to 7 days, such as transient erythema/edema and pain, postinflammatory hyperpigmentation (PIH), dry skin/exfoliation, lymphadenopathy, and irritant contact dermatitis. Persistent serious adverse effects included PIH, tram-track scarring, and granulomatous reactions. Factors that increase the risk of events are active infections, darker skin, and metal allergies. CONCLUSION: Microneedling is a relatively safe therapy. Most reported AEs are minimal, resolving quickly and spontaneously. Caution should be taken in patients with active infection, darker skin types, metal allergies, and when used in conjunction with products not approved for intradermal use.

Treatment Update of Port-Wine Stain: A Narrative Review.

BACKGROUND: Port-wine stain (PWS) is a congenital vascular malformation affecting 0.3–0.5% of normal population. These characteristic lesions arise due to the interplay of vascular, neural, and genetic factors. Treatment options include lasers, cosmetic tattooing, electrotherapy, cryosurgery, derma-abrasion, and skin grafting; however, none of these treatment alternatives appears to be satisfactory and is unable to provide consistent, satisfactory responses or even complete cures. Currently, laser is the treatment of choice, as it is comparatively safe and more effective than other procedures. The most commonly used modality is pulsed dye laser (PDL). The literature research includes peer-reviewed articles (clinical trials or scientific reviews). Studies were identified by searching electronic databases (MEDLINE and PubMed) to January 2020 and reference lists of respective articles. Only articles published in English language were included. J Drugs Dermatol. 20(5): doi:10.36849/JDD.5005.

Prospective Clinical Trial of the Latest Generation of Noninvasive Monopolar Radiofrequency for the Treatment of Facial and Upper Neck Skin Laxity.

BACKGROUND: Aging of the face and upper neck is a complex process characterized by loss of collagen and elastic fibers, resulting in clinical skin laxity. Noninvasive interventions such as monopolar capacitively coupled radiofrequency (MRF) have gained popularity, offering a safer and more convenient alternative to traditional surgical face lift. The latest MRF device features larger tips, vibration, cooling, and impedance matching. OBJECTIVE: We performed the first open-label clinical trial, measuring the efficacy, safety, and patient satisfaction of this device for noninvasive lifting and tightening of the face and upper neck. MATERIALS AND METHODS: Forty subjects 30 to 60 years of age with mild/moderate skin laxity of the face and upper neck were enrolled. After pretreatment with ketorolac 60 mg intramuscular injection, subjects underwent treatment with MRF. Follow-up evaluations were performed on Days 30, 60, and 180. RESULTS: Our study demonstrated that the newest generation MRF produced statistically significant improvement in skin laxity 6 months post-treatment, especially in the jowls and melolabial folds. According to the Investigator Global Aesthetic Improvement Score, 73% of subjects had improvement at 6 months post-treatment. Subject satisfaction and improvement questionnaires supported these findings. CONCLUSION: Our data coupled with the excellent adverse effect profile validates MRF as an attractive treatment modality for facial and upper neck skin laxity.

Investigate the improvement of facial skin texture with the VISIA system after total thyroidectomy.

BACKGROUND: During clinical practice we have noticed that some patients with hyperthyroidism have finer skin with less wrinkles, pores, and spots after thyroidectomy, and the improvement can be observed within a few weeks after the operation. However, there is no evidence or study in the literature to proof this finding. AIM AND OBJECTIVE: This study was designed to evaluate and quantify the skin characters of patients with hyperthyroidism before and after thyroidectomy. MATERIAL AND METHODS: This is a prospective study to include patients with hyperthyroidism who received total thyroidectomy between March 1st, 2018 and February 28th, 2019. The patients received blood test for T4 and TSH analysis and VISIA measurements for skin texture quantification, at the preoperative stage, three, and six months postoperatively. A total of 8 patients were included. Repeated measurement was used to determine the lab data and VISIA measurement changes before and after the operation. Mauchly's sphericity test was performed to determine whether the violation of sphericity occurs, and the Greenhouse-Geisser correction was used when the violation of sphericity occurs. RESULTS: All the patients were female and generally healthy without systemic medical disease except the hyperthyroidism. The T4 and TSH levels were not significantly different before and after the thyroidectomy. In terms of the skin character measurements, the wrinkles, texture, pores, UV spots, and brown spots were not improved after thyroidectomy. A trend of improvement in spots, red area, and porphyrin was noted, although not statistically significant. CONCLUSIONS: Surgical removal of the thyroid gland in patients with hyperthyroidism does not improve the skin quality and texture in examinations via the VISIA system.

Intense Pulsed Light: A Methodical Approach to Understanding Clinical Endpoints.

BACKGROUND: Intense Pulsed Light (IPL) is a non-coherent polychromatic broadband filtered flashlamp that emits light in the spectrum of approximately 400–1200 nm. Its effects on photorejuvenation are well documented. The goal of this study is to help practitioners better conceptualize and fine tune IPL device settings in order to produce the most effective and safest clinical outcome. MATERIALS/METHODS: This was a prospective study testing several filters (515 nm; 560 nm; 590 nm and 530–650; 900–1200 nm vascular filter), fluences, pulse durations, and pulse numbers (ie, multiple sequence pulsing or MSP) with a new IPL system. RESULTS: Post-procedure erythema response was more pronounced with increasing fluence, decreasing wavelength, fewer pulses and shorter pulse duration. The exception was the 515 nm filter with regard to pulse duration, which was observed to have a more pronounced response with longer pulse durations. The overall clinical outcome at the 4-week follow-up visit demonstrated greatest improvement in erythema and pigmentation using the 515 nm filter on a Fitzpatrick Skin Type III individual. CONCLUSION: Greatest clinical endpoint response at 4-week follow-up was observed with more robust initial responses. This was most apparent at higher fluence levels and fewer pulse counts. However, when the IPL is pushed to aggressive parameters, there is risk of hypopigmentation and hair loss as seen in this case study. Skin type is an important consideration when using IPL and MSP adds to its safety profile. J Drugs Dermatol. 2021;20(2):203-207. doi:10.36849/JDD.5638.

Needle Manufacturing, Quality Control, and Optimization for Patient Comfort.

INTRODUCTION: There is an increasing rise of cosmetic injectables. We sought to understand the manufacturing, quality control process, and needle selection of hypodermic needles for fillers. OBJECTIVE: To understand the process of manufacturing and quality control of hypodermic needles and the relevance to an aesthetic clinician. METHODS: We conducted a search of the internet and contacted medical device companies to understand the manufacturing process. We then collaborated with the Executive director of global pharmaceutical technology from Abbvie as well as the packaging and device engineer at Galderma and summarized our findings. Finally, we reviewed the literature and summarized existing recommendations on techniques to minimize pain related to injection. RESULTS: Hypodermic needles undergo an extensive manufacturing and regulatory process. Many considerations are taken into account in needle manufacturing as well as the selection process with commercially available hyaluronic acid filler products. Needle manufacturers are held to universal standards though the International Organization for Standardization (ISO). Filler companies perform their own testing to evaluate suitability of needles for their product including leakage force, penetration force, extrusion force, etc. Finally, parameters such as needle length, needle diameter, and wall thickness are considered for selection of needle/hub with individual filler viscosity. CONCLUSION: There is extensive consideration that goes into needle manufacturing, quality control, and optimization for hyaluronic acid filler. Understanding the technical process helps inform the clinician and guide patient care for maximum comfort. J Drugs Dermatol. 2021;20(1):44-48. doi:10.36849/JDD.5591.

Rates of Vascular Occlusion Associated With Using Needles vs Cannulas for Filler Injection.

Importance: Soft-tissue augmentation with skin fillers can be delivered with needles or microcannulas, but unwanted vascular occlusions are possible. Objective: To determine whether filler-associated vascular occlusion events of the face occur more often with injections performed with needles than with microcannulas. Design, Setting, and Participants: This retrospective cohort study included a random sample of board-certified dermatologists deemed eligible based on membership in relevant professional societies and attendance at relevant national professional meetings. Participants completed detailed forms in which they could enter deidentified data and volume statistics pertaining to patients undergoing filler procedures in their practices. Data were collected from August 2018 to August 2019. Exposures: Injectable fillers approved by the US Food and Drug Administration delivered via needles or microcannulas. Main Outcomes and Measures: The primary outcome measure was intravascular occlusion. Occlusion events were graded by severity (no sequelae, scar, and ocular injury or blindness). Results: A total of 370 dermatologists (mean [SD] years in practice, 22.3 [11.1] years) participated and reported 1.7 million syringes injected. The risk of occlusion with any particular filler type using needle or cannula never exceeded 1 per 5000 syringes injected. Overall, 1 occlusion per 6410 per 1-mL syringe injections was observed with needles and 1 per 40 882 with cannulas (P < .001). Of the 370 participants, 106 (28.6%) reported at least 1 occlusion. Multivariate analysis found that injections with cannula had 77.1% lower odds of occlusion compared with needle injections. Participants injecting fillers for more than 5 years had 70.7% lower odds of occlusion than those who were less experienced. For each additional injection per week, the odds of occlusion decreased by 1%, and 85% of occlusions had no long-term sequelae. Nasolabial folds and lips were most likely to be occluded, with mean severity level of occlusions highest at the glabella. Conclusions and Relevance: In this cohort study, filler injections with either needles or cannulas were associated with a very low risk of intravascular occlusion events. Moreover, the vast majority of such events were minor and resolved without scar or other injury. Injections with microcannulas were less often associated with occlusion events than injections with needles. Occlusion risk per syringe appeared decreased after the first few years of clinical practice and was also lower among those who more frequently inject fillers. Whether a needle or cannula is most appropriate for injection may depend on patient factors, anatomic site, and the type of defect being treated.