The Role of Hyaluronidase for the Skin Necrosis Caused by Hyaluronic Acid Injection-Induced Embolism: A Rabbit Auricular Model Study

Administration Method and Potential Efficacy of Hyaluronidase for Hyaluronic Acid Filler-Related Vision Loss: A Systematic Review

BACKGROUND

With the global increase in the use of injectable fillers, more cases with serious adverse events such vision loss are being reported. This article aims to review the cases of hyaluronic acid (HA) filler-related vision loss and to discuss the potential efficacy of hyaluronidase (HYASE) treatment via different given methods.

METHODS

A total of 29 articles presenting 144 cases of HA filler-related vision loss were included in this study.

RESULTS

Most cases of HA filler-related vision impairment were reported from China, followed by Korea. The majority of cases were seen in women. The nose, forehead and glabella were the most commonly injection sites. All cases had vision impairment and nearly all cases were unilateral with immediate onset of visual signs and symptoms. Ophthalmic artery occlusion (OAO) and central retinal artery occlusion (CRAO) were the two most commonly involved arterial obstruction patterns featured with a very poor prognosis followed by branch retinal artery occlusion (BRAO), the most favorable involved arterial pattern for a better prognosis. HYASE given subcutaneously and intra-arterially helped with visual recovery to different degrees, while retrobulbar HYASE seemed to be less helpful.

CONCLUSION

Complications after HA-based filler injection are extremely rare but can cause disastrous visual impairment. HYASE given subcutaneously and intra-arterially helped with visual recovery to different extents, and the efficacy might be reinforced when performed together, while retrobulbar HYASE seemed to be less helpful. However, to accurately access the efficacy of HYASE via different administration methods, further randomized controlled trials are needed.

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 .

Is constant needle motion during soft tissue filler injections a safer procedure? A theoretical mathematical model for evaluating patient safety

BACKGROUND

The safety rationale behind the constant needle motion injection technique is based on the assumption that due to the constant needle motion and simultaneous soft tissue filler material administration a smaller amount of product per area may be injected into an artery if an artery within the range of the moving needle is inadvertently entered.

OBJECTIVE

To perform mathematical calculations for determining the probability for causing intra-arterial product administration when constantly moving the needle during facial aesthetic soft tissue filler injections.

METHODS

This study was designed as a theoretical investigation into the probabilities for causing adverse events due to intravascular injection of soft tissue filler material when constantly moving a 27-G needle during facial soft tissue filler administration.

RESULTS

It was revealed that with a higher number of conducted injection passes a greater soft tissue area can be covered by the needle. The odds of encountering an artery within the covered soft tissue volume and the odds of injecting any volume greater than zero into the arterial blood stream increases with the number of performed injection passes. This increase is greatest between 1 and 10 performed injection passes.

CONCLUSION

This model demonstrates that the constant needle motion technique increases the probability of encountering an artery within the treatment area and thus increases the odds for intra-arterial product administration. The constant needle motion technique does not increase safety but rather may increase the odds of causing intra-arterial product administration with the respective adverse consequences for the patient.

Vascular complications with necrotic lesions following filler injections: Literature systematic review

INTRODUCTION

Although the related risk of vascular necrosis due to filler injection is low, the outcomes can be severe when they occur. This systematic review aims to report the occurrence and treatment of vascular necrosis due to filler injection.

MATERIALS AND METHODS

The systematic review was performed according to PRISMA guidelines.

RESULTS

The results showed the most used treatment is a combination of pharmacologic therapy and hyaluronidase application, which is efficacy when applied in the first 4 h. In addition, even though management recommendations are available in literature, proper guidelines are unavailable due to the low number of complications occurrence.

CONCLUSION

Clinical and high-quality studies on treatment and management of filler injection combination are necessary to provide scientific evidence on what to do in case of vascular complication occurrence.

Modification of hyaluronic acid to enable click chemistry photo-crosslinking of hydrogels with tailorable degradation profiles

Hyaluronic acid (HA) is a naturally occurring mucopolysaccharide that, due to its inherent bioactivity and extracellular matrix-like structure, has the potential to be utilised extensively in tissue engineering. However, this glycosaminoglycan lacks the properties required for cellular adhesion and photo-crosslinking by UV light, which significantly hinders this polymers applicability. This research presents a method for modifying hyaluronic acid via thiolation and methacrylation to generate a novel photo-crosslinkable polymer with improved physicochemical properties, biocompatibility and the potential to customize biodegradability according to the ratio of monomers used. A decrease in stiffness proportional to increasing thiol concentration was observed when testing the compressive strength of hydrogels. Conversely, it was noted that the storage moduli of hydrogels increased proportionally to thiol concentration indicating a greater degree of cross-linking with the addition of thiol. The addition of thiol to HA increased the biocompatibility of the material in both neuronal and glial cell lines and improved the degradability of methacrylated HA. Due to the enhanced physicochemical properties and biocompatibility imparted by the introduction of thiolated HA, this novel hydrogel system could have numerous bioengineering applications.

Organogel of Acai Oil in Cosmetics: Microstructure, Stability, Rheology and Mechanical Properties

Organogel (OG) is a semi-solid material composed of gelling molecules organized in the presence of an appropriate organic solvent, through physical or chemical interactions, in a continuous net. This investigation aimed at preparing and characterizing an organogel from acai oil with hyaluronic acid (HA) structured by 12-hydroxystearic acid (12-HSA), aiming at topical anti-aging application. Organogels containing or not containing HA were analyzed by Fourier-transform Infrared Spectroscopy, polarized light optical microscopy, thermal analysis, texture analysis, rheology, HA quantification and oxidative stability. The organogel containing hyaluronic acid (OG + HA) has a spherulitic texture morphology with a net-like structure and absorption bands that evidenced the presence of HA in the three-dimensional net of organogel. The thermal analysis confirmed the gelation and the insertion of HA, as well as a good thermal stability, which is also confirmed by the study of oxidative stability carried out under different temperature conditions for 90 days. The texture and rheology studies indicated a viscoelastic behavior. HA quantification shows the efficiency of the HA cross-linking process in the three-dimensional net of organogel with 11.22 µg/mL for cross-linked HA. Thus, it is concluded that OG + HA shows potentially promising physicochemical characteristics for the development of a cosmetic system.

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.

Cloning, expression, and characterization of a glycosaminoglycan lyase from Vibrio sp. H240

Glycosaminoglycan lyase is an effective tool for the functional studies of glycosaminoglycans and for the preparation of oligosaccharides. In this study, a new glycosaminoglycan lyase HCLaseV with a molecular weight of 90 kDa was cloned, expressed, and characterized from Vibrio sp. H240. The lyase belonged to the polysaccharide lyase (PL)- 8 family. HCLaseV showed enzyme activities toward chondroitin sulfate A, chondroitin sulfate B, chondroitin sulfate C, and hyaluronic acid. HCLaseV exhibited the highest activity against HA at pH 7.0 and 40 °C. HCLaseV was an endo-type enzyme whose degradation end-product was unsaturated disaccharides. Ca²⁺ inhibited the activity of HCLaseV to a certain extent, which was different from most of the enzymes in the PL-8 family. Mutagenesis studies showed that the Ca²⁺ inhibition might be related to the Asn²⁴⁴ residue. The sequence homology was evaluated by mutagenesis studies, and the catalytic residues in HCLaseV were presumed to be His²⁷⁸, Trp⁴⁸⁵, and Tyr²⁸⁷. These characteristics are helpful for further basic research and application.

A case of cutaneous necrosis due to intra-articular hyaluronic acid and treated with hyaluronidase

A 66-year-old woman presented to the hospital with cutaneous necrosis of her right ankle and foot. Her symptoms began immediately after an intra-articular injection of hyaluronic acid for ankle osteoarthritis, which was performed 6 days before. Histopathology showed an intra-vascular hyaluronic acid embolus. The initial treatment approach was conservative, but the patient’s clinical state degraded. She was thus treated with sub-cutaneous hyaluronidase, the enzyme that degrades hyaluronic acid, which yielded a moderate improvement even though it was administered 22 days after the initial hyaluronic acid injection. Although hyaluronic acid embolism and subsequent cutaneous necrosis are well-known complications of dermal fillers, there are few reported cases of embolism following intra-articular injection. To our knowledge, this is the first time hyaluronidase has been used in this setting.

Management of vascular complications following facial hyaluronic acid injection: High-dose hyaluronidase protocol: A technical note

Aesthetic medicine has experienced major developments in recent years, which is illustrated by the increasing number of hyaluronic acid injected in the area of facial rejuvenation. Although considered low risk, it can rarely result in arterial embolization with potentially major aesthetic and functional consequences. These vascular complications range from livedo to skin necrosis to permanent blindness. In such cases the management is urgent. Early care leads to a successful recovery but most of the time the diagnosis is delayed. Several treatments have been suggested and the use of hyaluronidase is decisive. There is no official guideline on the use of hyaluronidase. The aim of this article is to propose a protocol to clarify the management of vascular complications of HA with high doses of hyaluronidase based on the literature and our clinical experience of 35 patients treated.

Histological and Quantitative Appraisal of the Intradermal and Subcutaneous Distribution of the Hyaluronic Acid Injected into the Nasolabial Fold

BACKGROUND

Histological analysis of hyaluronic acid (HA) applied in the nasolabial fold (NLF) studied gel distribution into the dermis and subcutaneous fat, correlating density of NLF tissues, with cohesivity, concentration and degradation of HA.

METHOD

Ten patients received two injection points on each NLF. They were intradermal near the nasal ala and subcutaneous near the oral commissure. Injection points received 0.1 ml of 24 mg/ml HA cross-linked by BDDE 2.0 ppm through a bolus technique injection without retrograde backflow. Biopsies were taken 72 h and 9 months after application to histological analysis.

RESULTS

Dermis density fragmented the gel into small nodules, spreading it into the reticular dermis. Seventy-two hours after application, average diameter of the small nodules was 0.30 mm and at month nine 0.05 mm. Softness of the subcutaneous fat and high concentration of HA created a single and compact nodule. Seventy-two hours after application, average of nodule diameters was 1.05 mm and at month nine 0.49 mm. HA biodegradation occurred on the external surface of the gel. The single nodule offered small contact surface to enzymes, slowing gel degradation. The sum average of the diameters of the small nodules offered a large contact surface to enzymes, accelerating gel degradation.

CONCLUSION

Permanence of the HA into the tissues depended on the relationship between the gel distribution and its degradation. Due to the small contact surface of the single nodule to enzymes, permanence of the HA into the subcutaneous fat was more extended than into the dermis.

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 .

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.

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.