Pathophysiology Study of Filler-Induced Blindness

Arterial Vascularization of the Forehead in Aesthetic Dermatology Procedures: A Review

Background: The growing popularity of aesthetic procedures on the face raises the question of their safety. The forehead region is crucial aesthetically, but due to its abundant vascularization, it is also one of the most dangerous areas for dermatologic procedures, especially in the glabella area. The purpose of this article is to review the literature on the arterial vascularization of the forehead to identify potential high-risk zones for aesthetic dermatology procedures. Methods: A database search (PubMed, Web of Science, Scopus, and Embase) was conducted, and the titles and abstracts of all identified studies were screened, followed by full-text evaluation. Results: We identified 714 articles during the database search, and 25 articles were included in the review. The included studies used cadaveric dissection and computed tomography applied to cadavers as well as Doppler ultrasonography on volunteers to evaluate the forehead arteries (supratrochlear (STrA), supraorbital (SOA), central (CA), paracentral artery (PCA), and frontal branch of superficial temporal artery(FBSTA)). A total of 1714 cases involving the forehead arteries were analyzed. The included arteries were observed over a relatively large area, and their locations varied. The CA and PCA in cadaver studies were observed in an area of 0.2 to 10.8 mm and 0.8 to 16.2 mm, respectively, on the entire path from the glabellar point to the frontal prominence point. The distances from the midline in cadaveric studies at various measurement points ranged from 0.6 to 28.0 mm for the superficial branch of the STrA and 13.6 to 40.7 mm for the deep branch of STrA. In case of SOA, the distance from the midline ranged from 23 to 32 mm. Measurements from the midline in Doppler studies ranged from 0 to 23 mm for STrA and from 10 to 50 mm for the SOA. In studies using computed tomography, STrA was observed at a distance of 11 to 21 mm and the SOA at a distance of 21 to 32 mm, both lateral to the midline. Conclusions: Medical professionals should be aware of zones where frontal arteries are more likely to be encountered. The glabella region appears to be one of the most dangerous areas for dermatologic procedures. It is believed that the supratrochlear, supraorbital, and the paracentral arteries may cause ophthalmic complications due to occlusion of the ophthalmic artery, while this risk for the frontal branch of the superficial temporal artery seems to be low but cannot be completely excluded.

The Aesthetic Surgery Education and Research Foundation (ASERF): A 30-Year Retrospective Analysis

Federal government research grants provide limited funding to plastic surgeon-scientists, with reconstructive research taking precedence over aesthetic research. The Aesthetic Surgery Education and Research Foundation (ASERF) is a nonprofit, 501(c)(3) organization that seeks to support innovative, diverse research endeavors within aesthetic surgery. A total of 130 ASERF-funded studies and 32 non-funded applications from 1992 to 2022 were reviewed. Kruskal Wallis, Fisher's exact, and chi-squared tests were utilized to assess the potential relationship between self-identified gender, practice setting, geographical location, and study type with individual grant amounts and grant funding decision. Although significant differences were observed between male and female grant recipient h-indices (P < .05), there were no differences in the amount of funding they received (P > .05). Grant amounts were also consistent between study types as well as principal investigator practice settings and geographical locations (P > .05). The subanalysis revealed that the practice setting of the primary investigator (PI) was the only variable to exhibit a significant association with the decision to award funding (P < .05). Further, of the 61 applicants between 2017 and 2022, only 2 PIs self-identified as female. ASERF serves as an excellent funding source for global aesthetic surgery. To promote further research diversification, increased emphasis should be placed on recruiting applicants from outside academia and those who identify as female or gender nonbinary.

Nonsurgical Gluteal Volume Correction with Hyaluronic Acid: A Retrospective Study to Assess Long-term Safety and Efficacy

Background

Augmentation and reshaping of body volume, particularly in the gluteal area, presents a significant challenge in aesthetic surgery. Hyaluronic acid (HA) fillers have emerged as an effective and safe tool for such indications, but literature examining nonsurgical gluteal reshaping with HA remains limited. This study aims to evaluate the long-term safety of using recommended volumes of HA body fillers for nonsurgical gluteal augmentation.

Methods

A retrospective, observational study was carried out across multiple centers in Italy and the United Arab Emirates. The study involved participants between 22 and 53 years of age who underwent gluteal augmentation using HA body filler (HYAcorp MLF1/2) between 2017 and 2021, with up to 4 years and 7 months of follow-up. Participants and investigators independently evaluated the procedure's effectiveness by comparing pre- and posttreatment photographs. The Global Aesthetic Improvement Scale was used to assess posttreatment satisfaction by both participants and investigators. All adverse effects (AEs) were recorded.

Results

The study included a diverse group of 91 participants. No serious adverse events were reported, with the majority of AE occurring shortly after treatment and resolving in 1 week. AEs were more frequently observed in participants with previous treatments using different substances in the treatment area.

Conclusions

The real-world application of HA body filler (HYAcorp MLF1/2) for gluteal augmentation in the participants of this study showed the treatment's effectiveness, with no severe adverse events reported among the participants. High levels of satisfaction were reported among both participants and investigators.

Needle Microcores: Can They Pose an Occlusive Threat with Nonparticulate Injections?

SUMMARY

The incidence of vascular occlusion injuries has risen substantially along with the increasing popularity of cosmetic injectables. Among these occurrences, instances of soft-tissue ischemic events following the injection of nonparticulate solutions, such as botulinum, represent an enigmatic etiology that has yet to be fully understood. One hypothesized mechanism of injury underlying these events relates to the accidental capture and intravascular ejection of needle microcores, defined as submillimeter tissue fragments trapped by the beveled lumen of a needle during conventional injections. To test this hypothesis, the authors conducted a cytologic evaluation of dermal remnants incidentally captured by 31-G tuberculin needles following repeated injections into postrhytidectomy skin fragments. Their findings revealed the presence of dermal tissue microcores ranging from 100 to 275 μm in diameter with an overall microcoring incidence of 0.7%. These findings confirm the ability of ultrafine needles, commonly used in botulinum injections, to produce tissue microcores that may serve as causative agents of vascular occlusion with nonparticulate solutions. Awareness of this mechanism of injury may be of benefit in the early recognition and management of these rare occurrences.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Does injecting small amounts of fillers prevent the development of secondary blindness?

INTRODUCTION

Inadvertent entry of filler products into the supratrochlear, supraorbital, or dorsal nasal arteries, among other branches of the ophthalmic artery, might result in an immediate and devastating loss of vision. We wanted to examine how much filler could block the ophthalmic artery.

MATERIALS AND METHODS

Twenty-nine fresh cadavers were examined. We exposed the arterial supply to the opthalmic artery by dissecting the orbital area. Thereafter, 17 filler injections were introduced into the supratrochlear, supraorbital, and dorsal nasal arteries each. The amount of filler injection that completely blocked the ophthalmic artery was measured. Additionally, one of the head specimens was processed using phosphotungstic acid-based contrast enhancement micro-computed tomography to analyze each arteries to obstruct its whole ophthalmic artery.

RESULTS

The supratrochlear, supraorbital, and dorsal nasal arteries had mean volumes in milliliter (mean ± standard deviation) of 0.0397 ± 0.010 mL, 0.0409 ± 0.00932 mL, and 0.0368 ± 0.00732 mL, respectively. However, the arteries did not differ significantly.

CONCLUSION

Even a modest amount of filler injection can completely block the ophthalmic artery, resulting in visual loss.

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 .

External carotid artery to ophthalmic artery flow associated with internal carotid artery stenosis

PURPOSE

One of the most devastating complications of facial filler injection is sudden ischemic blindness. However, its mechanisms and predisposing factors are poorly understood. The purpose of this study was to investigate the prevalence of external carotid artery (ECA) to ophthalmic artery (OA) anterograde flow in patients with internal carotid artery (ICA) stenosis and in a control population without carotid disease.

METHODS

In this cross-sectional cohort study, two groups of patients who underwent catheter cerebral angiography over a 5-year period were identified: patients with symptomatic ICA stenosis and a control group of patients with refractory epistaxis undergoing embolization. Angiograms were reviewed by an interventional neuroradiologist. The primary outcome measure was the presence of ECA to OA flow, defined as choroidal blush before filling of the circle of Willis. Secondary outcome measures included the percentage and location of ICA stenosis and ECA anastomotic branches involved.

RESULTS

The study included 149 patients with ICA stenosis and 69 control patients. ECA to OA flow was more prevalent in patients with ICA stenosis (34.9%) compared to controls (2.9%) (p < .001). Logistic regression demonstrated that for each 10% increase in ICA stenosis over 70%, there was 2.8 times increased risk of ECA to OA flow (p < .001).

CONCLUSIONS

ECA to ICA anterograde flow can be demonstrated in approximately 3% of control patients and in over 1/3 of patients with symptomatic carotid stenosis. This provides a plausible pathway for small filler particles to pass with blood flow from the facial to the ophthalmic circulation.

An Experimental Model Exhibiting Anterograde and Retrograde Vascular Occlusion of Facial Fillers to Avoid Vision Loss

Background

Facial filler injection techniques that help decrease the risk of vascular occlusion are an important growing area of study. This study demonstrates a model of injecting fillers into a simulated bifurcated arterial system, using different sized needle gauges at a constant injection pressure.

Methods

Three facial fillers were injected into a bifurcated intravenous tubing with continuous irrigation at a constant pressure to simulate a vascular system. Videography was used to observe for retrograde flow through the simulated supratrochlear artery to the bifurcation point, where the filler was redirected by anterograde flow into the branch representing the ophthalmic artery.

Results

Filler injection with retrograde flow to the bifurcation occurred with all the 27G needle trials. In comparison, the 30G needle trials were only able to reach the bifurcation point in three of the nine trials. The average time to the bifurcation point with subsequent ophthalmic artery anterograde flow with the 27G and 30G needles were 8.44 (95% confidence interval ±2.06) and 33.33 (95% confidence interval ±16.56) seconds, respectively.

Conclusions

Larger 27G needles consistently reached retrograde flow and the bifurcation point faster than 30G needles. This study suggests thinner needles may be less likely to cause retrograde occlusion.

Multiple Retinal Emboli and Medial Canthal Swelling Following Injection of Acellular Porcine Urinary Bladder Matrix for Hair Restoration

Acellular porcine urinary bladder matrix promotes wound healing and is also used to stimulate hair growth. A 64-year-old female presented with acute-onset OD pain and decreased visual acuity after subcutaneous injection of acellular porcine urinary bladder matrix at the hairline. Fundus examination revealed multiple emboli at retinal arcade branch points, and fluorescein angiography demonstrated corresponding areas of peripheral nonperfusion. Two weeks later, external examination revealed new swelling of the right medial canthus without erythema or fluctuance, which was felt to possibly represent recruitment of vessels after occlusion in the facial vasculature. At 1-month follow up, visual acuity of the OD improved with resolution of right medial canthal swelling. Fundus examination was normal with no visible emboli. Herein, the authors present a case of retinal occlusion and medial canthal swelling following injection of acellular porcine urinary bladder matrix for hair restoration, which to the authors knowledge has not been previously reported.

Long-term Prognosis of Vision Loss Caused by Facial Hyaluronic Acid Injections and the Potential Approaches to Address This Catastrophic Event

BACKGROUND

Vision loss is a serious complication of hyaluronic acid (HA) filler injections, and long-term observations regarding the prognosis, particularly with angiography, are rare.

OBJECTIVES

This study aimed to investigate the long-term prognosis and living status of patients with visual defects due to HA filler injections.

METHODS

Nine patients with vision loss caused by HA filler injections and receiving different treatments were included and followed up for 2 to 6 years after their accident. Follow-ups, including outpatient ophthalmologic examinations, were performed.

RESULTS

In the follow-up observation, all patients had reintegrated into society and work. The prognosis was similar for all hyaluronidase treatments, including retrobulbar injections and superselective ophthalmic artery thrombolysis. The facial appearance was not remarkably affected, and only 3 patients reported slight scarring. Ptosis disappeared in all the patients, and slight strabismus was found in 5 patients. However, vision improvement was very limited, even in the patients whose occluded retinal central artery received reperfusion.

CONCLUSIONS

This long-term follow-up showed that the patients with vision loss caused by HA filler injections could reintegrate into society after treatment. Although the embolization of the retinal central artery led to reperfusion, vision was not restored, which further demonstrated the difficulty of recovering vision with the current treatment and the importance of prophylaxis. Autohydrolysis of HA by incorporating hyaluronidase-containing stimuli-responsive nanoparticles and a dual-pipe syringe are potential future approaches to address this catastrophic event.

Comparison of Hand-Held Doppler and Indocyanine Green Angiography in Preoperative Design of Expanded Forehead Flaps for Nasal Reconstruction

BACKGROUND

Despite the different approaches for detection of perforators, methods of vascular mapping of the expanded forehead flap for nasal reconstruction are rarely described. This article aimed to present our experience in the preoperative design of the expanded forehead flap for nasal reconstruction and to compare the clinical practice of hand-held Doppler and indocyanine green angiography (ICGA) in vascular mapping for nasal reconstruction with the expanded forehead flap.

METHODS

From October 2019 to April 2022, 26 patients underwent nasal reconstruction using expanded forehead flap. The authors performed preoperative vascular mapping on 16 patients by hand-held Doppler alone, and on 10 patients by hand-held Doppler and ICGA primary outcomes considered were the visualization of the main vascular course of the flap obtained by hand-held Doppler or ICGA, intraoperative observation of the flap, and its postoperative complications.

RESULTS

Indocyanine green angiography provides a better detection in distal flap and the branches of the supratrochlear artery. Vein detection by ICGA generally corresponds to the results obtained by the combination of hand-held Doppler and transillumination test. In the group that only used hand-held Doppler, 2 patients presented hemodynamic complications in the margin of the flap and 1 patient presented partial necrosis postoperatively. No complication was found in the group that used ICGA.

CONCLUSIONS

It is recommended to use the ICGA for preoperative planning, as it yields highly accurate vascular courses. As an alternative to other methods, hand-held Doppler is also an effective tool.

LEVEL OF EVIDENCE

IV.

Ultrasound-Guided Targeted vs Regional Flooding: A Comparative Study for Improving the Clinical Outcome in Soft Tissue Filler Vascular Adverse Event Management

BACKGROUND

Adverse vascular event management following hyaluronic acid-based aesthetic injections relies on the administration of hyaluronidase which is capable of enzymatically degrading the injected product and improving clinical symptoms. Two protocols are currently available to manage such complications: "ultrasound-guided targeted" and "flooding".

OBJECTIVES

The aim of this study was to compare the 2 protocols in terms of the volume of hyaluronidase utilized, and the onset and degree of clinical improvement.

METHODS

A comparative case series of 39 patients was retrospectively evaluated. The patients were initially treated with the "flooding" protocol and then treated with the "ultrasound-guided targeted" protocol due to no or little improvement.

RESULTS

The "ultrasound-guided targeted" protocol utilized a mean [standard deviation] total of 122.5 [34] IU of hyaluronidase, whereas the "flooding" protocol utilized 1519.4 [1137] IU, which represents a statistically significant reduced amount of injected hyaluronidase (P = 0.028). There was no clinical improvement in 92.3% and only little improvement in 7.7% of the treated patients following the first applied "flooding" protocol, but there was a 100% immediate improvement when subsequently treated with the "ultrasound-guided targeted" protocol. Ultrasound imaging revealed that the application of hyaluronidase restored normal blood flow both in the perivascular space and in the superficially located subdermal soft tissues.

CONCLUSIONS

Despite its limitations in study design, this retrospectively evaluated case series revealed that the "ultrasound-guided targeted" protocol utilized less hyaluronidase and restored clinically visible symptoms faster. The effect of this protocol is best explained by the perforasome concept which will need to be investigated further in future studies.

LEVEL OF EVIDENCE: 4

Evaluation of supratrochlear artery depth and course variations by Doppler ultrasonography along the glabellar frown lines for safer filler injections

PURPOSE

Hyaluronic acid (HA) injection is a popular nonsurgical, rejuvenating procedure to treat glabellar frown lines, which has devastating complications such as blindness and skin necrosis due to the arterial occlusion of supratrochlear artery (STA). Therefore, when injecting into the frown lines, knowledge of the STA's depth and plane is necessary to prevent possible adverse events. The aim of this study was to identify the depths of STA in the area of the frown lines in order to maximize safety during filler injections.

METHODS

Supratrochlear artery depth measurements were performed at the level of eyebrow and at the level of 1.5 cm above the eyebrow. Superficial duplex Doppler ultrasonography was performed of 71 cases.

RESULTS

In the eyebrow level, the epidermis-artery distance (EAD) is between 1,8 and 5.9 mm, and the artery-periost distance (APD) is between 0.7 and 3.7 mm. In the 1.5 cm superior level of the eyebrow, the EAD is between 1.8 and 5.1 mm and the APD is between 0.6 and 3.8 mm. There was no significant difference between the depth measurements of the right and left STA. At the eyebrow level, APD is greater in men than in women. As the body mass index increases, the EAD and APD depth increases. EAD depth increases with increasing age.

CONCLUSIONS

Based on the findings of this study, safe filler injections to correct the glabellar frown lines can be possible with intradermal injections just below the ryhtide. In the glabellar region, subcutaneous and supraperiosteal injections seems to be risky.

Upper Facial Anastomoses Between the External and Internal Carotid Vascular Territories - A 3D Computed Tomographic Investigation

BACKGROUND

Facial regions with a high risk for causing injection-related visual comprise are dual-supply vascular areas such as the nose, glabella, and forehead. These regions have in common that they receive arterial blood supply both by branches of the internal (ICA) and the external carotid artery (ECA).

OBJECTIVE

The authors sought to investigate the anastomotic pathways between ICA and ECA branches in the upper face.

METHODS

Postmortem computed tomographic angiographic scans of n = 38 Chinese non-embalmed hemifaces (25 males, 13 females; mean age, 37.79 [11.8] years; mean BMI, 21.90 [2.3] kg/m2) were conducted. Data analysis relied on the calculation of depth, distances, and pathways of forehead and temporal arteries to investigate the number of anastomotic connections, the connecting branches, and the layer of connection between ICA and ECA territories.

RESULTS

Between ICA and ECA territories, only 1 connection in 57.9%, 2 connections in 31.6%, 3 connections in 5.3%, and 4 and 5 connections in 2.6% each were identified. A superficial connection was observed in 15.8% whereas in 84.2% the anastomotic connection was identified to be both superficial and deep.

CONCLUSIONS

Adverse events following facial minimally invasive soft-tissue filler injections for aesthetic purposes are not frequent but devastating if they occur. Anatomic knowledge as presented in this study can help to increase awareness of 3-dimensional vascular anastomotic pathways and identify safer injection zones and safer fascial planes. Evidence-based injection techniques should be followed, and safety aspects should be placed over the aesthetic outcome.

Effectiveness of retrobulbar hyaluronidase in the treatment of visual loss caused by periocular hyaluronic acid injection. A systematic review

INTRODUCTION

Blindness after periocular cosmetic filler injection is a rare but devastating complication. Complication management protocols recommend injecting retrobulbar hyaluronidase if visual loss related to accidental intravascular injection of hyaluronic acid occurs. Given the dramatic increase in cosmetic filler injections and the variety of professionals that can deliver them, it is reasonable to assume that the incidence of complications will rise significantly.

OBJECTIVE

To evaluate if there is evidence-based efficacy of retrobulbar hyaluronidase injection in visual loss secondary to periocular cosmetic filler injection.

MATERIAL AND METHODS

The authors performed a search of English and Spanish language articles following the PRISMA statement published on the use of retrobulbar hyaluronidase to reverse vision loss precipitated by hyaluronic acid gel fillers. Articles reviewed included case reports/series and experimental investigations. We identified a total of 13 patients in this review following defined inclusion and exclusion criteria. Finally, we included 15 articles in the study, 12 of them were cases / case series. The 2 remaining articles are experimental studies in animals with a control group, in which after causing selective occlusion of the ophthalmic artery, serial injections of retroocular hyaluronidase are administered with control of visual function.

RESULTS

Of the 15 articles included in the study, we studied 17 patients treated with retrobulbar hyaluronidase for hyaluronic acid-induced blindness. Improvement was demonstrated in 3 cases. Animal studies demonstrate variable data are provided regarding the recovery of visual acuity.

CONCLUSIONS

There is no confirmed evidence of retrobulbar hyaluronidase injection effectiveness in treating visual loss due to accidental intravascular injection of hyaluronic acid. More studies are needed to show the efficacy of hyaluronidase as a treatment for blindness caused by hyaluronic acid.

Bridging a Century-Old Problem: The Pathophysiology and Molecular Mechanisms of HA Filler-Induced Vascular Occlusion (FIVO)—Implications for Therapeutic Interventions

Biocompatible hyaluronic acid (HA, hyaluronan) gel implants have altered the therapeutic landscape of surgery and medicine, fostering an array of innovative products that include viscosurgical aids, synovial supplements, and drug-eluting nanomaterials. However, it is perhaps the explosive growth in the cosmetic applications of injectable dermal fillers that has captured the brightest spotlight, emerging as the dominant modality in plastic surgery and aesthetic medicine. The popularity surge with which injectable HA fillers have risen to in vogue status has also brought a concomitant increase in the incidence of once-rare iatrogenic vaso-occlusive injuries ranging from disfiguring facial skin necrosis to disabling neuro-ophthalmological sequelae. As our understanding of the pathophysiology of these injuries has evolved, supplemented by more than a century of astute observations, the formulation of novel therapeutic and preventative strategies has permitted the amelioration of this burdensome complication. In this special issue article, we review the relevant mechanisms underlying HA filler-induced vascular occlusion (FIVO), with particular emphasis on the rheo-mechanical aspects of vascular blockade; the thromboembolic potential of HA mixtures; and the tissue-specific ischemic susceptibility of microvascular networks, which leads to underperfusion, hypoxia, and ultimate injury. In addition, recent therapeutic advances and novel considerations on the prevention and management of muco-cutaneous and neuro-ophthalmological complications are examined.

Sudden vision loss and neurological deficits after facial hyaluronic acid filler injection

BACKGROUND

The ongoing expansion of the cosmetic armamentarium of facial rejuvenation fails to uncover the inherent risks of cosmetic interventions. Informed consent to all risks of cosmetic filler injections and potential sequelae, including ocular and neurological complications, should be carefully ensured. We present two cases of complications following facial hyaluronic acid filler injections.

CASE PRESENTATIONS

Case 1: A 43-year-old woman presented with monocular vision loss of the left eye, associated ptosis, ophthalmoplegia, periocular pain and nausea, cutaneous changes of the glabella region and forehead, and sensory impairment in the left maxillary branch dermatome (V2) after receiving a hyaluronic acid (HA) filler injection into the left glabellar area. On ophthalmological examination, an ophthalmic artery occlusion (OAO) was diagnosed upon identification of a "cherry-red spot". Magnetic resonance imaging (MRI) revealed a left ischemic optic neuropathy. Supportive therapy and hyaluronidase injections were initiated. A follow-up MRI of the head performed two months after presentation corresponded to stable MRI findings. The patient had irreversible and complete vision loss of the left eye, however, the ptosis resolved. Case 2: A 29-year-old woman was admitted to hospital a few hours after a rhinoplasty and cheek augmentation with hyaluronic acid, presenting with acute monocular vision loss in the right eye, retrobulbar pain, fatigue and vomiting. In addition, the patient presented a harbinger of impending skin necrosis and a complete oculomotor nerve palsy on the right side, choroidal ischemia and vision impairment. Supportive treatment and hyaluronidase injections into the ischemic tissue were initiated. A small scar at the tip of the nose, vision impairment and an irregular pupillary margin on the right side persisted at follow-up.

CONCLUSION

These two case reports and the literature review emphasize the pathophysiological mechanisms leading to potentially devastating complications. In order to reduce the risk of vision loss secondary to cosmetic filler injections, practitioners should possess a thorough knowledge of anatomy and preventive strategies.

Facial Injections and Blindness: A Review on Anatomy

ABSTRACT

With the sudden emergence of new medical aesthetic fillers, the number of fillers injected worldwide has exploded, but there are also worrying risks in the pursuit of beauty. At present, many cases of blindness caused by injection of aesthetic fillers have been reported. Most of the cases are caused by irreversible vascular embolism. This is a rare yet greatly feared complication of using facial cosmetic fillers. This article reviewed and analyzed the literature and summarized the changes in the anatomical structure of facial blood vessels related to blindness during facial injection.

Reevaluation of the Layered Anatomy of the Forehead: Introducing the Subfrontalis Fascia and the Retrofrontalis Fat Compartments

BACKGROUND

Novel imaging methods have provided new insights into the layered anatomy of the forehead. This study seeks to critically reevaluate the layered anatomy of the forehead by using ultrasound imaging and cadaveric dissection to provide an accurate anatomical description that can be used to guide safer surgical and minimally invasive frontal procedures.

METHODS

This study used ultrasound imaging in a sample of 20 volunteers (12 female and eight male volunteers; aged 35.25 ± 4.2 years; body mass index, 24.28 ± 3.5 kg/m2) and cadaveric dissections of 16 body donors (12 female and four male body donors; aged 72.76 ± 9.5 years) to reevaluate the layered anatomy of the forehead. Layer-by-layer dissections and ultrasound-based measurements of the frontal structures guided conclusions.

RESULTS

The following layered arrangement was identified: layer 1, skin; layer 2, superficial fatty layer; layer 3, suprafrontalis fascia; layer 4, orbicularis oculi and frontalis muscle (same plane); layer 5, a homogenous layer of fat [preseptal fat (in the upper eyelid), retro-orbicularis fat (deep to the orbicularis oculi muscle), and retro-frontalis fat (deep to the frontalis muscle); layer 6, subfrontalis fascia; layer 7, preperiosteal fat within the prefrontal space in the lower forehead and deep compartments in the upper forehead; and layer 8, periosteum.

CONCLUSIONS

The results of this study add to the current understanding of the layered arrangement of the forehead. The combination of ultrasound imaging and cadaveric dissections provided evidence for a continuous fatty layer deep to the frontalis muscle.

Thrombogenicity of Hyaluronic Acid Fillers: A Quantitative Thrombodynamics Study

PURPOSE

At present, there is a paucity of data regarding the thrombogenicity of hyaluronic acid fillers (HAFs). This article quantitatively analyses the thrombogenicity of 2 commonly used HAFs: Restylane Lyft and Juvéderm Ultra.

METHODS

Thrombogenicity was assessed using the Thrombodynamics Analyzer System and plasma obtained from healthy controls. Following the addition of HAFs or control, spontaneous clot formation time, initial rate of clot growth, average rate of clot growth over 30 minutes, and clot size at 30 minutes was measured for each sample. The median of differences between each group were analyzed.

RESULTS

Nine individuals with a mean (SD) age of 37 (17) years, participated in the study. Initial rate of clot growth was significantly lower in plasma mixed with Juvéderm compared to control (p = 0.008) or Restylane (p = 0.038). The average rate of clot growth more than 30 minutes was significantly lower in both HAF groups (Restylane vs. control p = 0.038; Juvéderm vs. control p = 0.008), there was no significant difference between HAF groups (p = 0.635). Final clot size was significantly smaller with Juvéderm (p = 0.038 vs. control and p = 0.013 vs. Restylane). Spontaneous clot formation time did not significantly change with the addition of either HAF.

CONCLUSIONS

Juvéderm significantly reduces the initial rate of clot growth, the average rate of clot growth more than 30 minutes, and clot size, whereas the addition of Restylane decreases the average rate of clot growth without affecting overall clot size in healthy individuals.

The Change of Plane of the Supratrochlear and Supraorbital Arteries in the Forehead-An Ultrasound-Based Investigation

BACKGROUND

Injecting soft tissue fillers into the deep plane of the forehead carries the risk of injection-related visual compromise due to the specific course of the arterial vasculature.

OBJECTIVES

The aim of this study was to investigate the 2- and 3-dimensional location of the change of plane of the deep branch of the supratrochlear and supraorbital artery, respectively.

METHODS

A total of 50 patients (11 males and 39 females; mean age, 49.76 [13.8] years, mean body mass index, 22.53 [2.6] kg/m2) were investigated with ultrasound imaging. The total thickness and the distance of the arteries from the skin and bone surface were measured with an 18-MHz broadband compact linear array transducer.

RESULTS

The deep branch of the supraorbital artery changed plane from deep to superficial to the frontalis muscle at a mean distance of 13 mm (range, 7.0-19.0 mm) in males and at 14 mm (range, 4.0-24.0 mm) in females and for the deep branch of the supratrochlear artery at a mean distance of 14 mm in males and females (range, 10.0-19.0 in males, 4.0-27.0 in females) when measured from the superior orbital rim.

CONCLUSIONS

Based on the ultrasound findings in this study, it seems that the supraperiosteal plane of the upper and lower forehead could be targeted during soft tissue filler injections because the deep branches of both the supraorbital and supratrochlear arteries do not travel within this plane. The superficial plane of the lower forehead, however, should be avoided due to the unpredictability and inconsistent presence of the central and paracentral arteries.

LEVEL OF EVIDENCE: 4

The Usefulness of Magnetic Resonance Angiography to Analyze the Variable Arterial Facial Anatomy in an Effort to Reduce Filler-Associated Blindness: Anatomical Study and Visualization Through an Augmented Reality Application

BACKGROUND

The use of soft tissue fillers for facial rejuvenation is increasing rapidly and the complications, unfortunately, follow the same path. Blindness caused by intravascular filler injections is a rare but devastating complication. Knowledge of the individual arterial anatomy may aid the injector in avoiding injecting into an artery and thus to prevent blindness.

OBJECTIVES

To evaluate if the use of magnetic resonance angiography (MRA) may visualize the arterial facial anatomy in a contrast- and radiation-free way and study the individual arterial variations using an augmented reality (AR) image.

METHODS

The individual arterial anatomy of the 3 terminal branches of the ophthalmic artery (supraorbital [SO]; supratrochlear [STr]; and dorsal nasal [DN] arteries) of 20 volunteers was studied by a 3-Tesla MRI, combining infrared (IR) facial warming and 3-dimensional time-of-flight multiple overlapping thin slab acquisition MRA. The resulting visualization of the facial arteries was shown on the patient's face through AR technology.

RESULTS

The MRA was able to visualize the SO in 90.0%, STr in 92.5%, and DN arteries in 75% of the examined patients, as well as numerous variations in both vessel localization and path. Furthermore, a proof-of-concept of the AR visualization of the individual arterial anatomy was successfully implemented.

CONCLUSIONS

Dermal filler injectors should be aware of the risk of filler-induced blindness and familiarize themselves with the visualization of the variable facial vascular anatomy. The implementation of a one-time MRA and subsequent AR visualization may be useful in the accurate planning of minimally invasive facial rejuvenation procedures.

Revisit, Reform, and Redesign: A Novel Dissection Approach for Demonstrating Anatomy of the Orbit for Continuing Professional Development Education

Advanced postgraduate medical education for health-care professionals is constantly evolving. Understanding facial anatomy and especially its vascular system is crucial when performing soft tissue filler injections to avoid adverse events including tissue loss or irreversible blindness. Standard anatomical resources often fall short of elucidating clinically relevant concepts in more highly specialized areas of interest. A novel dissection approach for demonstrating the anatomy of the lateral orbit was presented at scientific meetings to participants from dermatology, plastic surgery, and general practice. Results from the post-course online survey (n = 52) were analyzed. The results of the survey reveal a high educational impact and a high clinical relevance of the novel dissection approach. In addition, the majority of respondents (97.7%; n = 51) felt that the exposed anatomical structure of the orbit and face improved their ability to safely perform cosmetic procedures on the face. More experienced respondents who had previously attended at least five cadaveric dissections were more likely to strongly agree that reviewing anatomy through this novel dissection approach increased their confidence in avoiding periorbital vascular danger zones. As minimally invasive outpatient procedures continue to evolve, practicing physicians and mid-level providers often face the challenge of having to reconcile preexisting anatomical knowledge with new clinical practice. Skills required to navigate high impact anatomy include visualization of structures that form the navigational landscape and avoidance of key danger zones. The novel dissection approach to the lateral orbit reflects the increasing focus on revisiting, reforming, and redesigning anatomy for continuing professional development activities.

The Course of the Angular Artery in the Midface: Implications for Surgical and Minimally Invasive Procedures

BACKGROUND

Previous anatomic studies have provided valuable information on the 2-dimensional course of the angular segment of the facial artery in the midface and its arterial connections. The third dimension (ie, the depth of the artery) is less well characterized.

OBJECTIVES

The objective of the present study was to describe the 3-dimensional pathway of the angular segment of the facial artery and its relationship to the muscles of facial expression.

METHODS

The bilateral location and the depth of the midfacial segment of the facial artery was measured utilizing multi-planar computed tomographic image analyses obtained from contrast agent-enhanced cranial computed tomographic scans of 156 Caucasians aged a of 45.19 ± 18.7 years and with a mean body mass index of 25.05 ± 4.9 kg/m2.

RESULTS

At the nasal ala, the mean depth of the main arterial trunk was 13.7 ± 3.7 mm (range, 2.7-25.0 mm), whereas at the medial canthus it was 1.02 ± 0.62 mm (range, 1.0-3.0 mm). This was reflected by the arteries' relationship to the midfacial muscles: at the nasal ala superficial to levator anguli oris in 62.0% but deep to the levator labii superioris alaeque nasi in 53.6%; at the medial canthus superficial to the levator labii superioris alaeque nasi in 83.1% and superficial to the orbicularis oculi in 82.7%.

CONCLUSIONS

The results presented herein confirm the high variability in the course of the angular segment of the facial artery. Various arterial pathways have been identified providing evidence that, in the midface, there is no guaranteed safe location for minimally invasive procedures.

A Safe Doppler Ultrasound-Guided Method for Nasolabial Fold Correction With Hyaluronic Acid Filler

BACKGROUND

Injection of hyaluronic acid filler, a common procedure for nasolabial fold correction, poses a risk of vascular compromise, which can result in skin necrosis and blindness.

OBJECTIVES

The aim of this study was to examine the facial arterial pathway in real time by Doppler ultrasound to avoid arterial complications during filler injections.

METHODS

The facial artery pathway of 40 patients (80 nasolabial folds; 2 men and 38 women; mean age, 46.5 years; range, 28-72 years) was examined by Doppler ultrasound before hyaluronic acid filler injection. On the basis of this ultrasound evaluation, the filler injection targeted the subdermal, subcutaneous, and deep to submuscular layers by bypassing the facial artery. The efficacy of the filler injection was evaluated for each patient.

RESULTS

The facial artery was detected lateral to the nasolabial fold in 31% of patients; it was detected beneath the nasolabial fold in the other patients as follows: subdermal layer, 13%; subcutaneous layer, 29%; muscular layer, 24%; and submuscular layer, 4%. The mean [standard deviation] Wrinkle Severity Rating Scale score was 3.68 [0.76] before injection and 2.28 [0.78] at 3 months after injection. Two patients experienced unilateral bruising of the nasolabial fold, which resolved after 2 weeks without treatment.

CONCLUSIONS

Doppler ultrasound can be considered as pretreatment tool for the prevention of vascular complications during filler injections to correct nasolabial folds.

LEVEL OF EVIDENCE: 4

Asymptomatic Stroke After Hyaluronic Acid Filler Injection: Case Report and Literature Review

Vascular compromise and blindness are reported but rare complications of facial soft tissue filler injections. Stroke is an even rarer complication resulting from intraarterial injection of fillers. We present a case of a patient suffering all 3 complications following hyaluronic acid filler injection: forehead skin vascular compromise, unilateral blindness, and ipsilateral subclinical strokes. Were it not for a stroke workup protocol, the incidental strokes may have otherwise gone undetected, suggesting the incidence of stroke from intraarterial injection may be higher than reported. Further, we review the literature and recommendations for prevention and management of threatened tissue ischemia and vision loss from facial filler injection.

LEVEL OF EVIDENCE: 5

Generation of Filler Emboli as a Mechanism for Filler-Related Blindness

BACKGROUND

Intra-arterial injection of fillers can lead to occlusion of the ophthalmic artery or its branches supplying the retina or the optic nerve. The mechanism through which this occurs is incompletely understood. We investigated the possibility of generating microparticles after injecting commercially available fillers into a flowing system in vitro.

METHODS

Three hyaluronic acid fillers and one calcium hydroxylapatite filler were injected into an artificial saline flow system mimicking arterial systolic blood pressure and corresponding to the diameter of the facial artery. All the saline at the end of the tube was collected, centrifuged, and inspected for filler particles.

RESULTS

After injection into the system, all fillers immediately disintegrated into small particles that were carried downstream with the flow of the saline. The saline at the end of the tube contained collections of filler.

CONCLUSION

Hyaluronic acid and hydroxylapatite fillers break up into small particles immediately after injection into a flowing system, generating emboli rather than a column of filler. The results of this study lead us to hypothesize another potential mechanism leading to filler-related blindness.

Blindness After Filler Injection: Mechanism and Treatment

Dermal fillers remain popular for facial rejuvenation but with its increasing use, the potential for more complications including blindness is present. This article focuses on the mechanism of filler-associated blindness, possible treatments, and future directions. Unfortunately, to date there is no proven treatment to reverse filler-induced blindness or visual compromise. It is essential for all injectors to discuss the potential ocular risks including blindness with their patients and obtain informed consent before filler injection.

Prevention and Management of Filler Induced Iatrogenic Stroke of the Eye

In the past few decades, minimally-invasive esthetic treatments and the use of injectable Hyaluronic Acid Gels and other filling agents to treat facial esthetics have increased dramatically. Although extremely rare, a filler can cause ocular and orbital ischemia by retrograde flow from the ophthalmic artery when injected in any of the anastomosis of the face. Once filler reaches the central retinal artery, blindness is inevitable, and no treatment is effective. While the risk of blindness happening with any filler injection is rare, the life-altering irreversible consequence of a procedure that was anticipated to be simple and beautifying is a reality that each injector must be prepared for with every injection. The parameters associated with an iatrogenic stroke of the eye are the site of injection, the injection technique, patient characteristics, and the material injected. Understanding the interplay of each of these variables might help us reduce the possibility of blindness during the injection of a soft-tissue cosmetic filler. Here, we explore the causes of Hyaluronic Acid Gels Filler embolic phenomena, review the natural course of the process, and discuss appropriate immediate interventions. We also (1) propose an education plan for injectors and describe how to carry out a focused ophthalmologic examination and procedural activities for a referral to an ophthalmologist, (2) outline steps to prevent emboli during filler injection, and (3) how to manage and support a patient with a sudden loss of vision during or immediately after a Hyaluronic Acid Gels filler treatment.

Aspiration: I don't do it and neither should you

Aspiration is a safety maneuver prior to filler injection in widespread use throughout the world, despite an absence of scientific evidence to its efficacy. This editorial questions the practice from a logical as well as a scientific point of view.

Endovascular Hyaluronidase Application Through Superselective Angiography to Rescue Blindness Caused by Hyaluronic Acid Injection

BACKGROUND

Blindness is a rare but catastrophic complication of facial hyaluronic acid (HA) injection. Although various means to rescue visual impairment have been employed, no consensus regarding effective treatment has yet been reached. We organized a multidisciplinary team to address this emergency situation by means of endovascular hyaluronidase application.

OBJECTIVES

The aim of this study was to investigate the direct delivery of hyaluronidase to ophthalmic artery occlusion through endovascular cannulation to resolve HA-induced blindness.

METHODS

Four patients with visual impairments caused by HA filler embolization were subjected to sequential treatments. Through superselective angiography, a microcatheter was introduced along a guidewire from the femoral artery to the ophthalmic artery to directly deliver hyaluronidase to the HA embolism. The safety and efficiency of this treatment were systematically analyzed.

RESULTS

Selective cerebral angiography demonstrated that the endovascular application of hyaluronidase significantly alleviated occlusion in 3 patients. One patient showed slight visual improvement, whereas the other patients showed no improvement in their visual function during a follow-up period of more than 3 months. One patient suffered from cerebral infarction in the left middle cerebral artery during the intervention surgery. Moreover, 2 patients showed multiple lacunar cerebral infarctions after the operation, whereas none exhibited symptoms of hemiplegia during follow-up.

CONCLUSIONS

Although the endovascular application of hyaluronidase could partially recanalize the occluded branches of the ophthalmic artery, it had limited effects on restoring vision. Considering the risks of vascular intervention surgery, this approach should be considered with caution.

LEVEL OF EVIDENCE: 5

The Force Required to Inject a Column of Filler Through Facial Arteries

BACKGROUND

Injectable fillers have become an integral part of facial rejuvenation, but vascular occlusion is a dreaded complication of such injections.

OBJECTIVE

To determine the force required by the fingertip onto the plunger of the syringe to cause retrograde migration.

METHODS

In this cadaver study, twelve 2-cm arterial segments and 4 fillers were tested. Injection pressure required to force a column of filler for 1 cm was measured. Five oculoplastics specialists were subsequently recruited and asked to inject the filler at a typical injection pressure.

RESULTS

The nonhyaluronic acid filler required significantly more pressure to cause propagation of the material compared with all other fillers (p < .01). None of the other fillers differed significantly from each other. Typical injection pressures generated by experienced injectors were significantly lower than that required to cause propagation of filler at the desired velocity and significantly lower than mean arterial pressure. Measured pressure required to cause filler propagation was well within the normal range of the finger strength that can be generated by humans.

CONCLUSION

Typical injection pressures from fingertip to plunger are lower than required to cause propagation of filler intravascularly.

Relationship Between Vertical Glabellar Lines and the Supratrochlear and Supraorbital Arteries

BACKGROUND

Glabellar soft tissue filler injections have been shown to be associated with a high risk of causing injection-related visual compromise.

OBJECTIVES

The aim of this study was to identify the course of the superficial branch of the supratrochlear and of the deep branch of the supraorbital artery in relation to the ipsilateral vertical glabellar line and to test whether an artery is located deep to this line.

METHODS

Forty-one healthy volunteers with a mean age of 26.17 [9.6] years and a mean BMI of 23.09 [2.3] kg/m2 were analyzed. Ultrasound imaging was applied to measure the diameters, distance from skin surface, distance between the midline, distance between vertical glabella lines, and the cutaneous projection of the supratrochlear/supraorbital arteries at rest and upon frowning.

RESULTS

The mean distance between the superficial branch of the supratrochlear artery and the ipsilateral vertical glabellar line was 10.59 [4.0] mm in males and 8.21 [4.0] mm in females, whereas it was 22.38 [5.5] mm for the supraorbital artery in males and 20.73 [5.6] mm in females. Upon frowning, a medial shift in supratrochlear arterial position of 1.63 mm in males and 1.84 mm in females and of 3.9 mm in supraorbital arterial position for both genders was observed. The mean depth of the supratrochlear artery was 3.34 [0.6] mm at rest, whereas the depth of the supraorbital artery was 3.54 [0.8] mm.

CONCLUSIONS

The hypothesis that injecting soft tissue fillers next to the vertical glabellar line is safe because the supratrochlear artery courses deep to the crease should be rejected. Additionally, the glabella and the supraorbital region should be considered as an area of mobile, rather than static, soft tissues.

A Consensus on Minimizing the Risk of Hyaluronic Acid Embolic Visual Loss and Suggestions for Immediate Bedside Management

Background

Hyaluronic acid fillers have a satisfactory safety profile. However, adverse reactions do occur, and rarely intravascular injection may lead to blindness. Currently there is no internationally recognized consensus on the prevention or management of blindness from hyaluronic acid filler.

Objectives

The authors sought to give guidance on how to minimize the risk and optimize the management of this rare but catastrophic adverse reaction.

Methods

A multinational group of experts in cosmetic injectables from multiple disciplines convened to review current best practice and develop updated consensus recommendations for prevention and bedside intervention if visual loss occurs after cosmetic injection of hyaluronic acid filler.

Results

The consensus group provided specific recommendations focusing on the consenting process, prevention, and early management of visual impairment related to intravascular hyaluronic acid filler injection.

Conclusions

Although visual loss due to filler injections is rare, it is important that both patient and physician be aware of this risk. In this paper the authors describe methods and techniques available to reduce the risk and also document suggested initial management should a clinician find themselves in this situation.

Level of Evidence: 5

Localization and Topography of the Arteries on the Middle Forehead Region for Eluding Complications Following Forehead Augmentation: Conventional Cadaveric Dissection and Ultrasonography Investigation

Forehead augmentation with filler injection is one of the most dangerous procedures associated with iatrogenic intravascular injection resulting in the severe complications. Nonetheless, few studies have determined the explicit arterial localization and topography related to the facial soft tissues and landmarks. Therefore, this study aimed to determine an arterial distribution and topography on the middle forehead region correlated with facial landmarks to grant an appropriate guideline for enhancing the safety of injection. Nineteen Thai embalmed cadavers were discovered with conventional dissection and 14 Thai healthy volunteers were investigated with ultrasonographic examination on the middle forehead. This study found that at the level of mid-frontal depression point, the transverse distance from the medial canthal vertical line to the superficial and deep branches of supraorbital artery were 9.1 mm and 15.1 mm, respectively. Whereas the depths from the skin of these arteries were 4.1 mm and 4.3 mm, respectively. Furthermore, the frontal branch of superficial temporal artery was detectable in 42.1% as an artery entering the forehead area. At the level of lateral canthal vertical line, the vertical distance of frontal branch was 31.6 mm, and the depth from skin of the artery was 2.7 mm. In conclusion, a proper injection technique could be performed based on an intensive arterial distribution and topography, and ultrasonographic examination before the injection is also suggested in order to restrict the opportunity of severe complications.

Death Caused by Vaginal Injection of Hyaluronic Acid and Collagen: A Case Report

With the expanding utilization of hyaluronic acid (HA) and collagen as cosmetic fillers in plastic and reconstructive surgery, complications due to their excessive use and/or irregular procedures warrant great caution. Recently, a fatal case occurred caused by a poorly regulated procedure of vaginal injection of HA and collagen. A 33-year-old female was admitted to the emergency department 3 hours after the operation with a chief complaint of dyspnea, which initiated 5 to 10 minutes after the operation. Her blood pressure remained low while dopamine pressor and fluid replacement were used. Computed tomography of the chest showed local exudation in the lower lobe of the left lung, enlargement of right atrium and ventricle, and uneven development of the bilateral inferior lobar artery with filling defects. Pulmonary computed tomography angiography and three-dimensional reconstruction showed continuous interruption of pulmonary artery branches of the posterior basal segment of the right lower lobe. Unfortunately, the clinical symptoms caused by vaginal injection aggravated rapidly and could not be effectively controlled. The patient died 9 hours after injection. Pulmonary complications after injection of cosmetic fillers are scarcely reported. Thus far, only 2 cases of HA-related pulmonary complications after vaginal injection have been described. The present case emphasizes that surgeons and other healthcare providers must be aware of the risk of serious pulmonary complications and even death associated with these 2 widely utilized injectable fillers. Level of Evidence: 5.

The Supratrochlear Artery Revisited: An Anatomic Review in Favor of Modern Cosmetic Applications in the Area

The supratrochlear artery represents a terminal branch of the ophthalmic artery. Cosmetic interventions may traumatize it, resulting in a circulation in the lesion in glabellar region and in the medial aspect of the forehead.

This review article aims to synopsise the existing knowledge of the anatomy of the supratrochlear artery in close correlation with minimally invasive cosmetic procedures in the facial area such as soft-tissue filler injections. Their possible adverse effects and their safe application based on the topographic anatomy were included.

A literature review was performed in PubMed/Medline online medical database.

The superficial course of the supratrochlear artery, as well as the rich, variable anastomotic network that it forms with the supraorbital, angular and dorsal nasal artery raise clinical questions in the case of soft-tissue filler injections in the nasoglabellar and central forehead area. Accidental cannulation of the supratrochlear artery and ultimately, the risk of embolization of the central retinal artery in a retrograde fashion might lead to injury with questionable cosmetic results.

Although the risk of complications from the use of soft tissue fillers is considered rare, once happen, the results could be devastating for the quality of life. Thus, the comprehension of the anatomy of the supratrochlear artery is paramount for the health practitioners.

Retrobulbar Injection for Hyaluronic Acid Gel Filler-Induced Blindness: A Review of Efficacy and Technique

While blindness after hyaluronic acid gel filler injection occurs only very rarely, it represents a devastating complication for the patient and the surgeon. Retrobulbar injection with hyaluronidase is the only known potential means of reversing this adverse event. However, positive outcomes remain anecdotal. We have attempted to review the current literature regarding possible efficacy and detail the indications and technique to be utilized, if hyaluronidase retrobulbar injection is to be attempted. LEVEL OF EVIDENCE V: 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 .

Risk Comparison of Filler Embolism Between Polymethyl Methacrylate (PMMA) and Hyaluronic Acid (HA)

Background

The incidence of vascular complications varies among different fillers. The main purpose of this study was to compare the risk of embolism between PMMA (Artecoll) and hyaluronic acid (HA, Restylane) after artery injection.

Methods

Rabbit ears were injected via the central artery with 0.1 ml PMMA (group A), 0.1 ml HA (group B), 0.2 ml PMMA (group C), or 0.2 mL HA (group D), respectively. The formation of transparent emboli was monitored right after injection. Tissue necrosis and histopathological changes were analyzed on day 7.

Results

With 0.1 ml injected volume, PMMA was dispersed within a few minutes and only 5% of the injected ears had mild necrosis on day 7, while HA tended to form obvious transparent emboli, an indication of blood vessel clotting, and 60% of injected ears showed necrosis on day 7. With 0.2 ml injected volume, PMMA had a risk of complete blood vessel clotting in between 0.1 ml PMMA group and 0.1 ml HA group, and 30% of injected ears had necrosis; in contrast, 100% of 0.2 ml HA-injected ears showed transparent emboli and necrosis. The necrosis areas were significantly increased in the HA groups compared with PMMA groups at the same injection volumes. HA injection also caused dilation of small blood vessels.

Conclusion

At the same injection volume, PMMA had less risk of embolism compared with HA. With increased injection volume, there were increased risks of embolism and necrosis for both PMMA and HA.

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.

Electronic supplementary material

The online version of this article (10.1007/s00266-019-01320-w) contains supplementary material, which is available to authorized users.

Update on Avoiding and Treating Blindness From Fillers: A Recent Review of the World Literature

BACKGROUND

Sudden loss of vision secondary to filler treatments is a rare but catastrophic complication.

OBJECTIVES

The aim of this study was to update the published cases of blindness after filler injection that have occurred since we published our review of 98 cases in 2015, and to discuss prevention and management strategies.

METHODS

A literature review was performed to identify all cases of visual complications caused by filler injection identified between January 2015 and September 2018.

RESULTS

Forty-eight new published cases of partial or complete vision loss after filler injection were identified. The sites that were highest risk were the nasal region (56.3%), glabella (27.1%), forehead (18.8%), and nasolabial fold (14.6%). Hyaluronic acid filler was the cause of this complication in 81.3% of cases. Vision loss, pain, ophthalmoplegia, and ptosis were the most common reported symptoms. Skin changes were seen in 43.8% of cases and central nervous system complications were seen in 18.8% of cases. Ten cases (20.8%) experienced complete recovery of vision, whereas 8 cases (16.7%) reported only partial recovery. Management strategies varied greatly and there were no treatments that were shown to be consistently successful.

CONCLUSIONS

Although the risk of blindness from fillers is rare, practitioners who inject filler should have a thorough knowledge of this complication including prevention and management strategies.

LEVEL OF EVIDENCE: 5