Hyaluronidase: what is your fear?

A treatment algorithm for hyaluronic acid filler related complications of the face

BACKGROUND

Throughout the last decade, a notable increase in HA-filler-related complications have been observed, owing to the increase in demand for filler injections and availability of multiple products.

OBJECTIVES

The aim is to provide practical advice on the best way to prevent and treat HA-filler-related complications.

METHODS

Thirty patients who experienced visible and/or symptomatic complications localized within the facial area were treated according to our algorithm. Patients with inflammatory lesions underwent antibiotic and anti-inflammatory therapy, followed by hyaluronidase injections. Patients with abscesses were treated with antibiotics, incision, and drainage. Each patient completed the dermatology-specific quality of life questionnaire (DLQI) at the first and last examinations.

RESULTS

Among the 29 patients who received antibiotic therapy, 3 healed without further treatment. However, 18 received hyaluronidase injections, 9 underwent incision and drainage, and 5 presented with fistulas and developed retracted scars. Moreover, 80% of the patients were completely healed, 13% significantly improved, and 3% did not show any improvement. The DLQI scores analysis showed a notable impact of patients' diseases on their quality of life, mainly in the terms of personal relationships and symptoms, with minor impacts on intimate relationships, ability to work, and study. We demonstrated that our algorithm resulted in a significant improvement in the overall quality of life at the last follow-up (p < 0.001).

CONCLUSIONS

The use of filler injections requires caution and specific training because they can lead to serious complications. If these complications are recognized promptly, healing can be optimized. Our treatment algorithm demonstrated high rate of healing and significant improvement in the patients' quality of life.

A Scoping Review of Hyaluronidase Use in Managing the Complications of Aesthetic Interventions

BACKGROUND

Hyaluronidase is used as an adjunct or main treatment to manage complications associated with cosmetic hyaluronic acid (HA) filler injections such as necrosis, blindness, hypersensitivity, delayed nodules, and poor aesthetic outcomes.

OBJECTIVE

To systematically map the available evidence and identify the gaps in knowledge on the effectiveness of hyaluronidase use in managing the aesthetic complications associated with HA injections (vascular occlusion, blindness, nodules, delayed hypersensivity, granuloma, poor aesthetic outcome).

METHODS

PubMed, Medline, Embase and Cochrane databases were used up to May 2022, to look for randomized clinical trials (RCTs), clinical trials, and retrospective case-control studies reporting on the use of hyaluronidase for managing the HA filler injection complications.

RESULTS

The database search yielded 395 studies; of those 5 RCTs (all carried out in the USA) were selected (53 subjects), indicating the effectiveness of hyaluronidase for removal of un-complicated injected HA nodules (forearm, upper arm, or back skin). The follow-ups ranged from 14 days to 4 years. The amount of HA filler injected into each site varied from 0.2 to 0.4 mL. A dose dependent response was observed for most HA fillers. No major adverse reactions were reported. Overall, for removal of every 0.1 mL of HA filler they injected 1.25-37.5 units of hyaluronidase (single injections). When 3 consecutive weekly hyaluronidase injection was used much lower doses of 0.375-2.25 unit was utilised. There was no evidence in a form of RCTs, clinical trials, and retrospective case-control studies on the removal/reversal of HA injections in the facial skin, or management of over-corrections, inflammatory nodules, or tissue ischemia/necrosis associated with HA filler injection.

CONCLUSION

Based on studies on the forearm, upper arm and back skin, hyaluronidase can be used for the reversal of uncomplicated HA filler injection nodule. However, further adequately powered studies are warranted to establish the ideal treatment protocol/dose of hyaluronidase for reversal of HA filler injections in the facial region or management of complications associated with aesthetic HA injection.

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 .

Exploring the role of intratendinous pressure in the pathogenesis of tendon pathology: a narrative review and conceptual framework

Despite the high prevalence of tendon pathology in athletes, the underlying pathogenesis is still poorly understood. Various aetiological theories have been presented and rejected in the past, but the tendon cell response model still holds true. This model describes how the tendon cell is the key regulator of the extracellular matrix and how pathology is induced by a failed adaptation to a disturbance of tissue homeostasis. Such failure has been attributed to various kinds of stressors (eg, mechanical, thermal and ischaemic), but crucial elements seem to be missing to fully understand the pathogenesis. Importantly, a disturbance of tissue pressure homeostasis has not yet been considered a possible factor, despite it being associated with numerous pathologies. Therefore, we conducted an extensive narrative literature review on the possible role of intratendinous pressure in the pathogenesis of tendon pathology. This review explores the current understanding of pressure dynamics and the role of tissue pressure in the pathogenesis of other disorders with structural similarities to tendons. By bridging these insights with known structural changes that occur in tendon pathology, a conceptual model was constituted. This model provides an overview of the possible mechanism of how an increase in intratendinous pressure might be involved in the development and progression of tendon pathology and contribute to tendon pain. In addition, some therapies that could reduce intratendinous pressure and accelerate tendon healing are proposed. Further experimental research is encouraged to investigate our hypotheses and to initiate debate on the relevance of intratendinous pressure in tendon pathology.

Case Report: Reversal of Hyaluronic Acid Rectal Wall Infiltration with Hyaluronidase

Peri-rectal spacers provide protection to the rectum for patients receiving radiation therapy treating prostate cancers. Commonly used hydrogel spacers hold the disadvantage that they cannot be readily reversed should inadvertent injection outside of the target area occurs, potentially leading to ischemia of the rectal mucosa leading to severe pain and ulceration, which can then lead to superinfection and pelvic abscess formation, and subsequently recto-prostatic fistulas. This could require major surgical intervention. New hyaluronic acid spacers are readily reversible with hyaluronidase and provide a valuable means to correct any misinjected spacer. We present a patient with prostate cancer who was planned for radiation therapy and required a rectal spacer. The hyaluronic acid rectal spacer was injected in part into the rectal wall. The patient was asymptomatic, and a sigmoidoscopy confirms healthy bowel mucosa only. The misinjected hyaluronic acid was successfully treated with targeted injection of hyaluronidase into only the rectal wall portion. Serial follow-up imaging demonstrated rapid dissolution of the misinjected hyaluronic acid with the well-positioned hyaluronic acid remaining. The patient did not experience any side effects of the hyaluronidase.

Does hyaluronidase injected in periocular area change skin ultrastructure: standardized in vitro analysis

BACKGROUND

Treatment with hyaluronic acid (HA) fillers as a strategy for rejuvenation has experienced a significant growth in recent years, accompanied by a parallel increase in its complications, the treatment of which, such as hyaluronidase, we must be aware of.

PATIENTS/METHODS

14 patients (28 eyes) had indication for upper blepharoplasty surgery in the Hospital Universitario y Politécnico La Fe. After surgery, periocular skin of one eye of each patient was infiltrated with 300 U of hyaluronidase (14 cases) while the skin of the fellow eye was preserved untreated (14 controls). All samples were studied by the Pathology department and finally 6 variables (skin structure alteration, degeneration of elastic fibers, deposits, collagen fibers destructuring, inflammation, other findings) were analyzed.

RESULTS

No differences in skin structure, elastic fibers and collagen dermal fibers were found between hyaluronidase treated skin and controls. A significant association between ex vivo application of hyaluronidase in periocular skin and the presence of amorphous extracellular deposits within the dermis was found.

CONCLUSIONS

Hyaluronidase applied ex vivo to periocular skin led to presence of deposits within the extracellular matrix compared to control eyelid skin but elastin and collagen dermis structure remained unaltered.

Hyaluronidases and hyaluronate lyases: From humans to bacteriophages

Hyaluronan is a non-sulfated negatively-charged linear polymer distributed in most parts of the human body, where it is located around cells in the extracellular matrix of connective tissues and plays an essential role in the organization of tissue architecture. Moreover, hyaluronan is involved in many biological processes and used in many clinical, cosmetic, pharmaceutic, and biotechnological applications worldwide. As interest in hyaluronan applications increases, so does interest in hyaluronidases and hyaluronate lyases, as these enzymes play a major part in hyaluronan degradation. Many hyaluronidases and hyaluronate lyases produced by eukaryotic cells, bacteria, and bacteriophages have so far been described and annotated, and their ability to cleave hyaluronan has been experimentally proven. These enzymes belong to several carbohydrate-active enzyme families, share very low sequence identity, and differ in their cleaving mechanisms and in their structural and functional properties. This review presents a summary of annotated and characterized hyaluronidases and hyaluronate lyases isolated from different sources belonging to distinct protein families, with a main focus on the binding and catalytic residues of the discussed enzymes in the context of their biochemical properties. In addition, the application potential of individual groups of hyaluronidases and hyaluronate lyases is evaluated.