The Role of Anastomotic Vessels in Controlling Tissue Viability and Defining Tissue Necrosis with Special Reference to Complications following Injection of Hyaluronic Acid Fillers

"Filler-Associated Acute Stroke Syndrome": Classification, Predictive Modelling of Hyaluronidase Efficacy, and Updated Case Review on Neurological and Visual Complications

INTRODUCTION

The rising use of soft tissue fillers for aesthetic procedures has seen an increase in complications, including vascular occlusions and neurological symptoms that resemble stroke. This study synthesizes information on central nervous system (CNS) complications post-filler injections and evaluates the effectiveness of hyaluronidase (HYAL) treatment.

METHODS

A thorough search of multiple databases, including PubMed, EMBASE, Scopus, Web of Science, Google Scholar, and Cochrane, focused on publications from January 2014 to January 2024. Criteria for inclusion covered reviews and case reports that documented CNS complications related to soft tissue fillers. Advanced statistical and computational techniques, including logistic regression, machine learning, and Bayesian analysis, were utilized to dissect the factors influencing therapeutic outcomes.

RESULTS

The analysis integrated findings from 20 reviews and systematic analyses, with 379 cases reported since 2018. Hyaluronic acid (HA) was the most commonly used filler, particularly in nasal region injections. The average age of patients was 38, with a notable increase in case reports in 2020. Initial presentation data revealed that 60.9% of patients experienced no light perception, while ptosis and ophthalmoplegia were present in 54.3 and 42.7% of cases, respectively. The statistical and machine learning analyses did not establish a significant linkage between the HYAL dosage and patient recovery; however, the injection site emerged as a critical determinant.

CONCLUSION

The study concludes that HYAL treatment, while vital for managing complications, varies in effectiveness based on the injection site and the timing of administration. The non-Newtonian characteristics of HA fillers may also affect the incidence of complications. The findings advocate for tailored treatment strategies incorporating individual patient variables, emphasizing prompt and precise intervention to mitigate the adverse effects of soft tissue fillers.

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 .

Intralesional hyaluronidase injection to relieve non-hyaluronic acid filler-induced vascular adverse events

BACKGROUND

Vascular adverse events (VAEs) occurring during injections of soft-tissue fillers are still considered a challenging issue for both patients and practitioners. Hyaluronidase can dissolve hyaluronic acid (HA)-based soft-tissue fillers during a VAE. For VAEs induced by non-HA fillers, the absence of an "antidote" is regarded as exceptionally challenging.

METHODS

This multicenter study describes a case series of three VAEs induced by non-HA fillers, for which ultrasound-guided hyaluronidase injections were incorporated into the treatment approach.

RESULTS

Two cases of calcium hydroxylapatite and one case of poly-L-lactic acid-induced VAEs are described, all of which were resolved without necrosis or scarring using a treatment approach with ultrasound-guided hyaluronidase injections.

CONCLUSIONS

Unlike the mechanical hypothesis, which assumes filler particles travel antegrade to block arterioles in a large skin area, we hypothesize vasoconstriction as the pivot in VAEs. Filler injection-induced spasms could lead to long-lasting vasoconstriction of the perforator arteries stemming from the central facial arteries. Our results underscore that perforasome vasoconstriction might be the leading cause of the ischemia and subsequent necrosis in VAEs and that relaxation of these perforasomes, rather than dissolving the filler material, resolves the clinical symptoms associated with VAEs.

Reticulated livedoid skin patterns after soft-tissue filler-related vascular adverse events

BACKGROUND

For the treatment of vascular adverse events caused by filler injections, duplex ultrasound imaging may be used. The findings of duplex ultrasound examination and the clinical features of reticulated livedoid skin patterns were compared with the hemifaces anatomy.

OBJECTIVE

The objective of this study was to link the reticulated livedoid skin patterns to the corresponding duplex ultrasound findings and the facial perforasomes.

METHODS

Duplex ultrasound imaging was used for the diagnosis and treatment of vascular adverse events. The clinical features and duplex ultrasound findings of 125 patients were investigated. Six cadaver hemifaces were examined to compare the typical livedo skin patterns with the vasculature of the face.

RESULTS

Clinically, the affected skin showed a similar reticulated pattern in each facial area corresponding with arterial anatomy and their perforators in the cadaver hemifaces. With duplex ultrasound, a disturbed microvascularization in the superficial fatty layer was visualized. After hyaluronidase injection, clinical improvement of the skin pattern was seen. Normalization of blood flow was noted accompanied by restoration of flow in the corresponding perforator artery. The skin patterns could be linked to the perforators of the superficial fat compartments.

CONCLUSION

The livedo skin patterns seen in vascular adverse events may reflect the involvement of the perforators.

Updated Filler Emergency Kit: Next-Generation Emergency Solution

INTRODUCTION

The rising popularity of facial filler injections has corresponded with an increase in reported complications. While a filler emergency kit was previously introduced, advancements in the field have highlighted certain limitations, prompting the development of the updated filler emergency kit (UFEK).

METHODS

The authors conducted literature research up to February 2023, focusing on PubMed and open web searches for articles referred to filler emergent complications: vascular occlusion, blindness and anaphylaxis. Approximately 1200 articles were obtained from PubMed and other sources, and 45 articles were reviewed.

RESULTS

The developed UFEK protocol delineates specific interventions meticulously tailored to address diverse emergent scenarios linked to soft tissue fillers complications. This protocol emphasizes the urgent requirement for timely and personalized interventions.

CONCLUSION

The UFEK offers a standardized, comprehensive and effective approach. This work contributes to the responsible and informed progression of the field of aesthetic medicine, providing more value and safety, both for clinicians and patients. Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Cosmetic Filler-Induced Vascular Occlusion: A Rising Threat Presenting to Emergency Departments

Vascular emergencies from cosmetic filler-induced vascular occlusion represent an iatrogenic etiology that poses a threat to patients, with sequelae that range from disfiguring skin necrosis to blindness and stroke. As cosmetic fillers continue to grow in popularity, the importance of early identification, triaging, and management of these rare but potentially disabling injuries has motivated efforts to educate the public and professional audiences. In this practice review article, we outline components of acute care pertaining to these injuries based on evolving practice guidelines and best evidence recommendations.

Nitrous Oxide Improves Tissue Perfusion in Vascular Occlusion Management

Filler-related vascular occlusion (VO) treatment remains challenging despite established protocols, including high-dose pulsed hyaluronidase injections and ultrasound-guided targeted injections. Managing patients' pain and anxiety during treatment presents additional difficulties. Nitrous oxide (N₂O) has been found to be effective for analgesia and anxiolysis in minor procedures, with a 55% reduction in photodynamic therapy pain, and a visual analog scale reduction from 6.6 to 2.9 for aesthetic laser treatment pain. Use of N₂O for analgesia, anxiolysis, or improvement of perfusion in VO has not been previously reported. We present two cases of filler-related VO management with high-dose hourly hyaluronidase injections and adjunctive use of self-administered 50% N₂O. Pain and anxiety of the treatment were self-reported by the patients. Capillary refill and livedo reticularis were monitored for establishing VO diagnosis and treatment outcome. In both cases, self-administration of N₂O led to contemporaneous improvement in skin perfusion. Patients reported decreased anxiety and pain during treatment. Hyaluronidase treatment led to permanent resolution of occlusion symptoms. N₂O presents a promising adjunctive treatment option for relief of pain and anxiety, and potentially additional perfusion improvement. Further investigation is necessary to better define N₂O's role in treating VO.

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

Use of the high-dose pulsed hyaluronidase protocol in the management of impending skin necrosis associated with hyaluronic acid fillers: a systematic review

Impending skin necrosis resulting from inadvertent intravascular injection of hyaluronic acid (HA) fillers can lead to tissue loss and significant scarring. In recent years, management trends have shifted from multimodal approaches to the sole use of high doses of hyaluronidase. The aim of this systematic review was to evaluate the effectiveness of the high-dose pulsed hyaluronidase management protocol in preventing skin necrosis and possible subsequent scarring. An online search of the bibliographic databases PubMed and Embase yielded 3039 articles. A total of 72 studies reporting 186 cases were found to be eligible for inclusion. The selection and evaluation process was done according to the PRISMA criteria. Included studies were assessed using the JBI and STROBE critical appraisal tools. The analysis of treatment outcomes was done according to the timing of treatment initiation and the type of intervention used. This review found that an immediate intervention using the high-dose pulsed hyaluronidase management protocol provided predictable and satisfactory outcomes. Initiating the protocol within 24 h of filler injection halted the progression of necrosis and prevented permanent sequelae. The conclusions are limited by the lack of a high level of evidence, since the only available sources of data are case reports and case series.

Early ultrasound for diagnosis and treatment of vascular adverse events with hyaluronic acid fillers

BACKGROUND

Hyaluronic acid fillers are known for a reliable safety profile, but complications do occur, even serious vascular adverse events.

OBJECTIVE

To improve the treatment outcome after a vascular adverse event with use of hyaluronic acid filler treatments.

METHODS

Duplex ultrasonography is used to detect the hyaluronic acid filler causing the intra-arterial obstruction.

RESULTS

If treated in time, 1 single treatment of ultrasonographically guided injections of hyaluronidase into the filler deposit will prevent skin necrosis.

CONCLUSION

Because the use of duplex ultrasonography adds extra essential information, its use may become an integral part of the prevention and treatment of injection adverse events.

Standards for aseptic techniques in medical aesthetic practices in the Benelux: Consensus recommendations

INTRODUCTION

While the demand for aesthetic procedures is rising, complications are rising alongside. Infection is a frequent complication, there is therefore an increased need for strict aseptic technique, particularly in procedures breaching the skin. The level of training of practitioners carrying out these procedures varies and there are no comprehensive guidelines on aseptic aesthetic practice in the Benelux region.

OBJECTIVE

Developing a step-by-step procedure for achieving and maintaining a high standard of aseptic conditions in a standard aesthetic practice in the Benelux region.

METHODS

A consensus group of 10 aesthetic medical practitioners (dermatologists, plastic surgeons, and cosmetic physicians) representing the Benelux region convened to discuss best practice for aseptic techniques in medical aesthetics. Step-by-step procedures were recommended to achieve optimal aseptic practice in private facilities and define important considerations for reducing infection risk. Recommendations were based on current evidence and extensive clinical experience.

RESULTS

Recommendations were made to achieve and maintain a high standard of asepsis and infection control. Guidance included maintaining high standard aseptic conditions of the injecting room, the injecting area on the patient, the injection procedure, the materials, and procedures commonly used to achieve aseptic conditions.

CONCLUSIONS

This expert consensus summary publication recommends aseptic procedures, setting a standard with the goal of minimizing rates of complications in aesthetic clinical practice in the Benelux region.

An illustrated anatomical approach to reducing vascular risk during facial soft tissue filler administration – a review

Vascular complications from soft tissue fillers can have catastrophic consequences for patients. Adverse events are rare, but they are increasing, and their appearance may be the result of intravascular injection. A comprehensive understanding of the 2-dimensional anatomy (distribution) and 3-dimensional anatomy (depth) of the facial vasculature is fundamental for the safe delivery of nonsurgical cosmetic procedures. The purpose of this review is to provide an illustrated approach to examine surgical anatomy specific to the facial vascular system and the anatomical considerations clinicians need to give in specific danger during injectable cosmetic procedures. A grounding in safety and anatomy will help the new injector to mitigate the risk of vascular complications.

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.

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.

Super-selective intra-arterial dissolution therapy for lingual artery occlusion resulting due to the use of hyaluronic acid for chin augmentation: The first reported case

As a consequence of the current trend of performing minimally invasive surgery, the use of injectable fillers has progressively increased in aesthetic surgery. Vascular complications resulting due to filling of hyaluronic acid (HA) in the chin have been previously reported. However, clinical evidence regarding the results of treatment of lingual artery occlusion with super-selective intra-arterial dissolution is lacking. Herein, we reported a case of lingual artery occlusion resulting due to HA filling for which tongue arteriography and catheter-directed dissolution were implemented via femoral artery intubation for the first time in the literature. The aim of this paper is to discuss the rare complications arising due to chin augmentation and their treatment to provide a deeper understanding of the use and side effects of HA in this procedure.

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.

The 10-Point Plan 2021: Updated Concepts for Improved Procedural Safety During Facial Filler Treatments

Dermal filler treatments require constant reassessment for improving and safeguarding the rapidly evolving aesthetic field. Suboptimal injection technique, patient selection and product knowledge have touted a concerning increase in filler complications, with new challenges such as the COVID-19 pandemic leading to new paradigms in the understanding, prevention, diagnosis and treatment of complications. The updated 10-point plan has been developed to curtail complications through consideration of causative factors, categorized as patient, product, and procedure-related. Patient-related factors include a preprocedural consultation with careful elucidation of skin conditions (acne, rosacea, dermatitis), systemic disease (allergies, autoimmune disease, underlying bacterial and viral disease (herpes simplex virus, COVID-19 infection), medications (antineoplastic drugs, recreational drugs) and previous cosmetic procedures (including fillers and energy-based devices). Patient assessment should include standardized photography and also evaluate the role of social media, ethnicity, gender, generational, and LGBTQ+ needs. Specified informed consent for both adverse events and their treatment is essential due to the increase in vascular complications, including the risk of blindness. Product-related factors include the powerful advantage of reversibility when using hyaluronic acid (HA) products. Product characteristics such as molecular weight and filler degradation should be understood. Product layering over late or minimally degradable fillers is still inadvisable due to the initial filler being teased into reactivity. Procedural factors such as consistent photographic documentation, procedural planning, aseptic non-touch technique (ANTT), knowledge of topographical anatomy and angiosomes, and technical dexterity including pinch anatomy and needle skills are of pivotal importance. The final section is dedicated to algorithms and checklists for managing and treating complications such as allergic hypersensitivity reactions, vascular events, infection, edema and late-onset adverse events (LOAEs). The updated 10-point plan is a methodical strategy aimed at further minimising the risk of dermal filler complications.

Importance of Choke Vessels in Injectable Fillers

Knowledge of facial anatomy is indispensable for dermatologists and plastic surgeons practicing aesthetic medicine, especially for those using fillers, as injection of fillers may be associated with serious complications such as vascular occlusion and blindness. Angiosome and choke vessels play an important role in vascular incidents occurring after filler injections. The objective of this article was to outline the anatomy and pathophysiology of choke vessels, a concept which is not well known to dermatologists.

Increasing Perfusion Pressure Does Not Distend Perforators or Anastomoses but Reveals Arteriovenous Shuntings

Background

It has been proposed that hyperperfusion of perforators and distension of anastomotic vessels may be a mechanism by which large perforator flaps are perfused. This study investigates whether increasing perfusion pressure of radiographic contrast in cadaveric studies altered the radiographic appearance of vessels, particularly by distending their anastomotic connections.

Methods

From 10 fresh cadavers, bilateral upper limbs above the elbow were removed. Three cadavers were excluded. Seven pairs of limbs were injected with lead oxide solutions via the brachial artery while distally monitoring intravascular pressure in the radial artery using a pressure transducer. One limb was injected slowly (0.5 mL/s) and the other rapidly (1.5 mL/s) to produce low and high perfusion pressures, respectively. Skin and subcutaneous tissue were then removed and radiographed.

Results

The filling of perforators and their larger caliber branches appeared unchanged between low- and high-pressure injections, with no significant increase in true anastomoses (P = 0.32) and no association between maximum perfusion pressure and number (P = 0.94) or caliber (P = 0.10). However, high-pressure injections revealed arteriovenous shunting with filling of the tributaries of the major veins.

Conclusions

This study demonstrated that increased perfusion pressure of the cutaneous arteries (1) did not change the caliber of vessels; (2) did not convert choke to true anastomoses; and (3) revealed arteriovenous shunting between major vessels with retrograde filling of venous tributaries as pressure increased. This suggests that it is not possible to distend anastomotic connections between vascular territories by increasing perfusion alone.

The "ART" of facial filler injections: Avoid, recognize, and treat hyaluronic acid-induced complications

BACKGROUND

Hyaluronic acid (HA) fillers are frequently used for cosmetic purposes as volumizers or as wrinkle fillers. One of the major advantages of hyaluronic acid use is the possibility to neutralize it by using hyaluronidase should complications occur.

PATIENT

A case of a 21-year-old female patient is presented, in whom a hyaluronic acid injection-induced vascular occlusion was seen four days after the initial injection, with increasing pain and severe signs of ischemia.

METHOD

Treatment consisted of an immediate hyaluronidase injection, supplemented with administration of acetylsalicylic acid, piracetam, low molecular weight heparin (LMWH), corticosteroids, analgesics, prophylactic antibiotics, application of topical nitroglycerin and warmth, smoking cessation, and hyperbaric oxygen therapy.

RESULTS

The initial progress and evolution of the deformity with possible therapeutic options are being discussed.

CONCLUSION

The "ART" (avoid, recognize, and treat) in handling filler complications is presented, as a new universal guideline for clinical aesthetic practitioners and injectors.

Near Complete Recovery of Visual Acuity After Calcium Hydroxylapatite Injection-Related Vision Loss: A Case Report and Literature Review

Injection of fillers has gained popularity over the past decades in aesthetic treatments. Calcium hydroxylapatite (CaHA; Radiesse) was introduced in the year 2003 and received approval from the Food and Drug Administration in 2006 for the treatment of moderate-to-severe wrinkles. The properties of CaHA include biostimulation, neocollagenesis, and stability over a long period. However, similar to other fillers, CaHA is associated with the risk of complications such as ecchymosis, inflammation, local infection, skin necrosis, and vascular occlusion. Iatrogenic vision loss remains the most devastating complication related to vascular occlusion. Development of vision impairment is associated with a relatively high risk of permanent damage to vision acuity and poor prognosis. The current report presents a case of a patient who suffered from skin necrosis, vision impairment, and ophthalmoplegia after the injection of CaHA into the nasal dorsum. Significant improvement in visual acuity was observed during hospitalization after the treatment. The patient recovered to near-normal visual acuity and completely recovered from ophthalmoplegia. We aimed to discuss the current treatment employed and review the literature on CaHA-related vision loss.