Topography of the deep temporal arteries and implications for performing safe aesthetic injections

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.

The Suitability of a Large Particle Hyaluronic Acid Filler for the Treatment of Temporal Hollowing

BACKGROUND

Hyaluronic acid (HA) fillers may be manufactured to have distinctive physical properties that optimize their use for specific indications. Fillers manufactured with large gel calibration (particle size; HA-V) may be particularly suitable for volumizing large surface areas such as the temporal hollows.

OBJECTIVE

To investigate the safety and effectiveness of HA-V for the treatment of temporal hollows.

MATERIALS AND METHODS

A prospective, open-label, single-cohort, clinical trial was conducted. Twenty-six women who presented with bilateral temporal hollows at baseline were recruited. All subjects received treatment with HA-V and were observed at 4 to 5 in-person visits over 16 weeks. Subjective and objective measures of safety and efficacy parameters were collected through 2- and 3-dimensional imagery, questionnaires/scales (i.e., subject satisfaction, global aesthetic improvement, temporal hollowing severity), and adverse event diaries.

RESULTS

To achieve optimal correction, the investigator used an average of 1.70 syringes per subject, per side. All treatments were performed using a bolus injection technique to place the product on the periosteum (bone) of the temporal region. Following optimal correction, all subjects (100%) displayed improvement in their global aesthetic appearance, and 25 of 26 subjects (96.15%) displayed ≥1 grade improvement on the temporal volume scale. Subject satisfaction was high, with 91.3% of subjects being satisfied with the appearance of their temporal regions following optimal correction.

CONCLUSION

In this pivotal trial, HA-V was evidenced to have an excellent safety profile and proven efficacy up to 16 weeks, making it a suitable HA filler for volumization of the temporal region.

Arterial Embolism After Facial Fat Grafting: A Systematic Literature Review

BACKGROUND

While autologous fat grafting of the face is considered a generally safe procedure, severe complications such as arterial embolism (AE) have been reported.

OBJECTIVE

To summarize data on injection-related visual compromise, stroke, and death caused by arterial embolism after facial fat transplantation.

MATERIALS AND METHODS

Plastic surgery societies were contacted for reports on AE after autologous facial fat injection. In addition, a systematic literature review was performed. Data extracted included study design, injection site/technique, symptoms, management, outcome, and etiology.

RESULTS

61 patients with a mean age of 33.56 ± 11.45 years were reported. Injections targeted the glabella or multiple facial regions (both n = 16/61, 26.2%) most commonly, followed by injections in the temples (n = 10/61, 16.4%) and the forehead (n = 9/61, 14.8%). The mean volume injected was 21.5 ± 21.5 ml. Visual symptoms were described most frequently (n = 24/58, 41.4%) followed by neurological symptoms (n = 20/58, 34.5%), or both (n = 13/58, 22.4%). Ophthalmic artery (OA, n = 26/60, 43.3%), anterior or middle cerebral artery (CA, n = 11/60, 18.3%) or both (n = 14/60, 23.3%) were most frequently occluded. Outcome analysis revealed permanent vision loss in all patients with OA occlusion (n = 26/26, 100%), neurological impairment in most patients with CA occlusion (n = 8/10, 80%), and vision loss in most patients suffering from both OA and CA occlusion (n = 7/11, 63.6%). Six patients died following embolisms.

CONCLUSIONS

AE causes severe complications such as blindness, stroke, and death. Due to a lack of high-quality data, no evidence-based treatment algorithms exist. To increase patient safety, a database collecting cases and complications should be established.

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 .

Deep Temporal Artery Anatomy: Implications for Improving the Safety of Deep Temporal Injections

BACKGROUND

Knowledge of the anatomy of the deep temporal artery (DTA) is critical to ensure safe filling of the deep temporal region. However, current treatment guidelines still focus on how to avoid the superficial temporal artery and the middle temporal vein, and an understanding of the safety of avoiding DTA injury is lacking.

OBJECTIVE

The purpose of this study was to determine the positioning and course of the DTA to help clinicians safely perform the injection and filling in the temporal region.

METHODS

Computed tomography (CT) scans and dissections of the skulls of 34 fresh frozen cadavers perfused with lead oxide were performed. Reconstruction and trajectory analysis of all DTA branches were performed using Mimics and MATLAB software.

RESULTS

In this study, the DTA was identified in all samples, which originated from the maxillary artery of the external carotid artery system. According to image reconstruction and anatomical observations, the distribution of the anterior and posterior branches of the DTA had two different distribution patterns. The anatomical level of the DTA is located between the temporal muscle and the periosteal layer. Compared with observations in previous studies, the anterior branch of the DTA is slightly different, and we found that its course is closer to the frontal area in Asian specimens.

CONCLUSION

The anatomical information on the DTA described in this study may help improve awareness of the safety of temporal injection by aesthetic physicians.

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 Table of Contents or online Instructions to Authors www.springer.com/00266. .

[Injection anatomy-a new discipline in aesthetic medicine]

The basic anatomical understanding of aesthetic medicine has changed fundamentally since the turn of the millennium. With the advent of modern minimally invasive injection procedures using botulinum toxin and hyaluronic acid fillers, anatomical structures that had previously received little attention and were not considered relevant have steadily gained in importance and moved into the scientific focus. Understanding the three-dimensional arrangement of the face with its defined anatomical layers and compartments serves the procedural dermatologist in the sense of a navigation system to optimize treatment success and patient safety when performing aesthetic injections in the facial region. The principles of the biomechanical interaction of the structures are of elementary importance in the creation of individual treatment plans for the implementation of natural and balanced therapeutic results. Modern injection anatomy as an interdisciplinary subject of the three fields of anatomy, dermatology and plastic surgery makes a decisive contribution here.

Ultrasound Imaging of Facial Vascular Neural Structures and Relevance to Aesthetic Injections: A Pictorial Essay

The facial and submental regions are supplied by complicated neurovascular networks; therefore, facial aesthetic injections may be associated with serious adverse events such as skin necrosis and blindness. Pre-injection localization of neurovascular structures using high-resolution ultrasound can theoretically prevent unexpected complications. Therefore, a systematic protocol that focuses on these facial neurovascular structures is warranted. In this pictorial essay, we discuss the sonoanatomy of facial and submental neurovascular structures and its relevance to aesthetic injections. Moreover, we have highlighted the mechanisms underlying potential neurovascular injuries during aesthetic injections.