Article

Polyalkylimide: A Nonstable Filler Over Time

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Abstract

Background: Polyalkylimide hydrogel is supposed to be a permanent, biocompatible implant. However, years after subcutaneous implantation clinical complications are seen. Objective: To increase the understanding of the changes that occur over time in this subdermal implanted filler. Materials and methods: The extruded filler material of 34 patients was evaluated by histologic examination. Results: In most patients who had cosmetic disturbances but no complaints, histology showed no immune cells in or around the filler material. In patients with an acute inflammatory response, giant cell invasion was seen in and around the filler material. Patients with chronic complaints showed a neutrophilic cell influx in the extruded filler. In all patients, degeneration and calcification of the material was noted. The polyalkylimide hydrogel changed over time, both macroscopically and microscopically. As in most of the patients no immune response was seen around the filler material, this may indicate that the material is biocompatible. Conclusion: The authors conclude that a dermal filler should not be judged solely on its biocompatible characteristics but also on the degradation process over time in the human body.

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... Around 2010, its use for cosmetic purposes was banned by several countries around the world due to the nature and frequency of complications, which could occur many years after the first injection [4][5]. ...
... The patient was very satisfied with her postoperative result, Figs. (1)(2)(3)(4)(5)(6) show the pr-operative and late post-operative results. ...
... 10 Most cases of filler migration present themselves as nodules which may be inflammatory or not. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Often the patient presents few years after the injection without volunteering the incidence of injection to the physician, masquerading as a multitude of alternative pathologies leading to diagnostic and therapeutic dilemma. 13,15,16 Among 85 patients presented with complications attributed to permanent filler injection, kadouch et al. reported filler migration and noninflammatory nodules accounting for 40% of total complications to be the main late complication. ...
... 8 The same authors in 2017 estimated the rate to be ''much higher'' based on the influx of more patients. 19 The most common sites of migration are forehead, glabella, nose and eyelid. 20 The mechanism of filler migration has been postulated to be related to several factors such as poor technique, higher volume of filler material injected, filler being injected under tissue with high pressure, gravity and muscle activity around the material. ...
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Purpose: To report the long-term follow-up results after surgical excision of migrated Bio-Alcamid fillers to the Periorbita area. Methods: A retrospective case series of all patients who underwent surgical removal of migrated Bio-Alcamid fillers to the Periorbita area with minimal follow-up of 1 year from January 2009 to January 2018 was done. Results: 16 female patients (24-52 y) presented with an upper or lower eyelid swelling 3-7 years following a filler injection in the nasal bridge, temporal or malar area. All patients had surgical excision of a granulomatous mass ranging in size from 1-3.5 cm. The histopathology report revealed a giant cell reaction in all patients. Follow-up periods ranged from 1 to 8 years. One patient developed lid retraction and another had recurrence 3 years later; the remaining had an unremarkable course. Conclusions: Filler migration is one of the potential complications associated with Bio-Alcamid soft tissue injection. It is important for all physicians to assess nodules/masses/swelling in the facial area to be aware that soft tissue fillers may migrate to a location away from their intended site of injection years after the injection. Patients undergoing surgical excision tend to have favorable overall long-term outcomes in terms of aesthetics and incidence of recurrence.
... The authors reported that the PAH changed macroscopically and microscopically suggesting a certain degree of degradation in the human body. 40 Inducible degradation is unknown with PAH fillers. 41 After injection of 0.1 mL in the forearm of one proband PMMA particles (Dermalive) had disappeared clinically at 6 months, while PMMA microspheres (Artecoll)-the predecessor of ArteFill-remained. ...
Article
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Dermal fillers are among the most versatile tools in esthetic medicine. A broad range of temporary, semipermanent, and permanent filler products is on the market. We performed a narrative review on spontaneous and induced degradation of dermal fillers in vitro and in vivo. Hyaluronic acid-based fillers are the most frequently used temporary fillers. The products differ in their hyaluronic acid content, cross-linking, and rheological parameters. Endogenous hyaluronidase and reactive oxygen species are responsible for the spontaneous degradation of these fillers. Hyaluronidase digests the filler material by cleavage of the β-1,4 glycosidic linkage between N-acetyl-glucosamine and d-glucuronic acid. The enzyme can be used for treatment of medical and cosmetic adverse events due to hyaluronic acid-based filler. Higher hyaluronidase content and higher degree of cross-linking are major factors contributing to filler persistence over time. Semipermanent fillers are poly-(d),l-lactic acid and calcium hydroxylapatite. These filler types are decomposed by hydrolysis and osteoclastic enzymes. They usually persist up to 2 years, in single patients even more than 5 years. Sodium thiosulfate can stimulate degradation of calcium hydroxylapatite, but it is slow acting and not effective in case of emergency. Permanent fillers may show some kind of modification in situ, but spontaneous or induced degradation has not been documented. Once implanted the permanent fillers remain lifelong. Intralesional laser treatment supports the removal of permanent filler material as an alternative to surgery. Besides biocompatibility and toxicity, filler materials should also be assessed for degradation to improve patient safety.
... However, for all types of permanent fillers, semi-permanent and resorbable fillers, delayed reactions with Bio-Alcamid® have also been described, such as inflammation, nodule formation, foreign body reaction with granuloma formation, hardening of the capsule, and nodule migration. An interesting study reported the nonstability of the product over time, leading to its degeneration, dehydration, and calcification formation [2,9]. Paresthesia is a severe delayed onset. ...
... However, most patients showed no immune response after many years of implantation. 19 Radiologic examinations can be useful in case of polyalkylimide complications. Polyalkylimide appears hyperintense on T2 W and hypointense on T1 W sequences and reveal no-post-contrast enhancement by magnetic resonance imaging (MRI). ...
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Background: Polyalkylimide is a permanent dermal filler that has been used for skin augmentation to ameliorate skin ageing. The massive volume injection has a higher risk of complication. This study aims to find collagen capsule formation by small volume polyalkylimide implantation.  Methods: We used an experimental post-test only control group design. The control group received subcutaneous NaCl injection, and the treatment group received subcutaneous polyalkylimide injection 0.018 mL (equal 1 mL in the humans). After five weeks, all rats (Rattus norvegicus) strain Wistar were sacrificed. The skin samples were collected and proceed for histologic staining. Capsule thickness was performed as mean ± SD.     Results: The treatment group showed polyalkylimide mass in subcutaneous tissue, collagen fibres surrounding the polyalkylimide, and no inflammatory cells. The collagen capsule thickness was 7.45 ± 0.78 µm.Conclusion: The small volume polyalkylimide subcutaneous injection-induced collagen capsule formation. The small volume implantation shows promising effects for skin augmentation.
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Although permanent fillers have been introduced in order to get long lasting results, many studies have shown numerous severe and disfiguring complications. Non-surgical procedures may mitigate those adverse events but the only way to remove the filler previously injected is represented by surgical excision. We present a pathway of facial surgical accesses to be performed achieving two goals: permanent filler removal and restore facial aesthetic balance. The proposed surgical accesses are already standardized in aesthetic surgical practice in order to avoid direct excision and unpleasant facial scar. 231 patients underwent surgery for permanent filler removal and aesthetic restoration of the involved facial area, represented by forehead, glabella, nose, cheeks, eyelids, chin, jawline and lips. Magnetic resonance evaluation was performed with the exception of lip patients evaluated with ultrasound. Postoperative follow-up was 12months to 6years. Subjective and objective methods were used to outcome evaluation according to FACE-Q questionnaire. Functional and aesthetic correction was scored using the patient-graded Global Aesthetic Improvement Scale(GAIS), overall patient satisfaction was assessed by a five-point scale questionnaire. Functional and aesthetic restoration was globally recognized as improved according to the Global Aesthetic Improvement Scale. Patients reported high levels of satisfaction assessed by a five-point scale questionnaire. A very good satisfaction level was registered in both subjective and objective judgment scores. To the best of our knowledge, we present the largest case series regarding surgical removal of permeant facial fillers. A proper pre-operative evaluation, filler removal followed by restorative facial aesthetic surgery technique is paramount to approach challenging cases.
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Soft tissue fillers used for facial rejuvenation can cause complications. We present two cases of late migration of injected fillers mimicking other pathology in the periocular area. Case 1 is a 52-year-old woman referred with chronic bilateral upper lid swelling, mimicking blepharochalasis syndrome, 5 ¹ / 2 years after undergoing injection of hyaluronic acid filler in both brows. Extensive blood investigations were normal. Bilateral, sequential upper lid biopsy revealed migrated hyaluronic acid filler, which was successfully treated with hyaluronidase. Case 2 is a 62-year-old woman who presented with a right lower lid mass 8 years after undergoing injection of polyalkylimide gel into both cheeks. CT scanning confirmed an intermediate density soft tissue mass overlying the inferior orbital rim. Histology from surgical excision reported chronic granulomatous inflammation due to migrated polyalkylimide gel. An awareness of late migration of fillers causing eyelid swelling and masses in the periocular area will prevent unnecessary investigations and facilitate prompt management.
Article
Objective This report presents the case of a patient who developed a nonthrombotic embolus attributed to a polyalkylimide dermal filler, and it also charts pharmacotherapeutic strategies for polyalkylimide complications reported in the literature. Case Summary A 31-year-old female presented to a community teaching hospital with dyspnea, hemoptysis, and fever. A thorough history revealed that the patient received intragluteal injections of a polyalkylimide dermal filler (Bio-Alcamid®) four days prior to hospitalization, although it was initially and incorrectly diagnosed as silicone embolism syndrome. High-dose intravenous steroids and antibiotics were ineffective, and the patient was transferred to a higher level of care for surgical management. Therein, the patient developed additional complications, including multiple thromboembolic events and need for long-term enteral nutrition. Following a 63-day stay in the intensive care unit and 13-day stay in an inpatient post-acute facility, the patient’s post-discharge care transitions included three subsequent emergency department visits related to enteral feeding tube malfunction. Practice Implications Polyalkylimide is a hydrogel polymer derived from acrylic acid that is used as a dermal filler. Post-injection complications include dermal filler migration and abscess formation. Surgical resection of the filler and prophylactic antibiotics have, anecdotally, been used with success. Comparatively, silicone dermal filler complications may be treated with high-dose intravenous corticosteroids. Although silicone and polyalkylimide are both classified as permanent dermal fillers, the management of their complications differs, especially with regard to medications. This case underscores the necessity for clinicians to accurately identify the type of dermal filler used in order to recommend effective medication management to treat complications. Unlike silicone dermal filler treatment, corticosteroids may actually exacerbate polyalkylimide dermal filler complications. β-lactam antibiotics for at least 14 days may be reasonable to treat the cutaneous infectious complications arising from polyalkylimide dermal filler use.
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BACKGROUND Facial aging is the result of intrinsic and extrinsic factors that lead to gradual reduction of dermal extracellular components and skin elasticity and wrinkle formation. A novel stent-shaped biodegradable and biocompatible scaffold device braided with absorbable polydioxanone (PDO) multifilaments was recently marketed for tissue suturing and augmentation.OBJECTIVE To explore tissue regeneration profiles following implantation of the stent-shaped hollow scaffold in rats and mini-pigs.MATERIALS AND METHODS The scaffold device was implanted under the panniculus carnosus of rat dorsal skin and in the subcutaneous layer of mini-pig dorsal skin. Tissue samples were harvested and histologically evaluated after 3 days and 1, 2, 4, and 12 weeks for rats and after 1, 2, 4, 8, and 12 weeks for mini-pigs.RESULTSType III collagen was slowly replaced by Type I collagen in the scaffold. Cells from the surrounding tissue infiltrated the hollow space of the scaffold, which induced de novo tissue regeneration in this space.CONCLUSION The novel stent-shaped scaffold used here may be useful for stimulated tissue remodeling of aged skin, collagen synthesis, and partial restoration of dermal matrix components. The cosmetic purpose of this novel soft tissue augmentation device should be clinically investigated in long-term studies.
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Synthetic polymer hydrogels constitute a group of biomaterials, used in numerous biomedical disciplines, and are still developing for new promising applications. The aim of this study is to review information about well known and the newest hydrogels, show the importance of water uptake and cross-linking type and classify them in accordance with their chemical structure.
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Hydrogels are a class of polymers that in the last decade have had a great development and application for soft tissue augmentation, due to their similarity to this tissue for their high water content. The in vitro effects of polyalkylmide hydrogel (pAI) and polyvinyl alcohol hydrogel (pVOH) on human lymphocytes and U937 cells viability, apoptosis and cell shape were investigated. Cell viability was always higher than 70%, thus showing the hydrogels were not cytotoxic for both cell lines. Some differences were, however, found. At short time, lymphocytes were very sensitive to the hydrogels incubation, while at long time, U937 cells were the most sensitive cells. Other differences on cell viability were related to the time of incubation, to the type of hydrogel and to the polymers concentration. Cell viability decreased only at the longest time of incubation and with the highest hydrogel concentration. Accordingly, cell death by apoptosis increased; necrosis was never observed in the cultures. Concentration- and hydrogel-dependent modifications of cell shape (bigger cell volume, elongations of cells) were observed in a few percentage of viable cells. In conclusion, the very high in vitro degree of biocompatibility shown by both hydrogels encourages their use as dermal fillers.
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All fillers are associated with the risk of both early and late complications. Early side effects such as swelling, redness, and bruising occur after intradermal or subdermal injections. The patient has to be aware of and accept these risks. Adverse events that last longer than 2 weeks can be attributable to technical shortcomings (e.g., too superficial an implantation of a long-lasting filler substance). Such adverse events can be treated with intradermal 5-fluorouracil, steroid injections, vascular lasers, or intense pulsed light, and later with dermabrasion or shaving. Late adverse events also include immunologic phenomena such as late-onset allergy and nonallergic foreign body granuloma. Both react well to intralesional steroid injections, which often have to be repeated to establish the right dose. Surgical excisions shall remain the last option and are indicated for hard lumps in the lips and visible hard nodules or hard granuloma in the subcutaneous fat.
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Raman spectra of poly-N,N,-dimethylacrylamide hydrogel were measured in order to investigate the mechanism of the structural changes in water and the polymer network during dehydration. The results show that the vibrational energies of the C=O and the O-H stretching modes increase with the extent of dehydration, whereas that of the CH(3) rocking mode decreases. The energy shifts observed in the C=O stretching and CH(3) rocking modes indicate that the polymer network shrinks with the dehydration and undergoes a glass transition at some point. The energy shifts of the O-H stretching modes are attributed to changes in the water structure with the structural change of the polymer network. By applying a structural model of bulk water to the spectra of the O-H stretching region, the local water structures in the gel and the dried glassy polymer were analyzed. The result shows that a tetragonal water structure consisting of four hydrogen bonds increases in the residual water of the dried glassy polymer, suggesting that the residual water forms a two-dimensional hydrogen-bonded network. The local water structure in a polymer might have important implications for the interpretation of properties of localized water, for instance, water in a mineral crack.
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Injectable fillers are commonly used in Plastic and Reconstructive Surgery to correct serious and slight aesthetic defects due to their low invasiveness and an easy implant technique procedure. Synthetic hydrogels are proposed as filler materials for their similarity with soft tissue and to avoid many disadvantages of naturally derived materials such as short persistence, allergenicity, and immunogenicity. Our studies are focused on the biocompatibility evaluation of a polyacrylic hydrogel containing alkylimide-amide groups and pyrogen free water (96%) (Bio-Alcamid by means of the in vitro cytotoxicity and mutagenicity assays and the in vivo skin irritation, sensitization test, and subcutaneous implant. All tests conducted on Bio-Alcamid showed no toxicity. It is a substance easy to inject and remove; it does not migrate, and its safety allows it to be a suitable filler for the correction of slight and also very serious aesthetic defects.
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The incorporation of negatively charged groups into the structure of synthetic polymers is frequently advocated as a method for enhancing their calcification capacity required in orthopedic and dental applications. However, the results reported by various research groups are rather contentious, since inhibitory effects have also been observed in some studies. In the present study, phosphate groups were introduced in poly(2-hydroxyethyl methacrylate) (PHEMA) by copolymerization with 10% mol of either mono(2-acryloyloxyethyl) phosphate (MAEP) or mono(2-methacryloyloxyethyl) phosphate (MMEP). Incubation of these hydrogels for determined durations (1-9 weeks) in a simulated body fluid (SBF) solution induced deposition of calcium phosphate (CaP) deposits of whitlockite type. After 9 weeks, the amount of calcium deposited on the phosphate-containing polymers was four times lower than that found on PHEMA, as determined by X-ray photoelectron spectroscopy (XPS). Samples of copolymer HEMA-MAEP were implanted subcutaneously in rats and evaluated after 9 weeks. No CaP deposits could be detected on the copolymer by XPS or energy dispersive X-ray spectroscopy, while PHEMA samples were massively calcified. It was concluded that the presence of phosphate groups decreased the calcification capacity of the hydrogels, and that in the conditions of this study, the phosphate groups had an inhibitory effect on the deposition of CaP phases on HEMA-based hydrogels.
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The foreign body reaction composed of macrophages and foreign body giant cells is the end-stage response of the inflammatory and wound healing responses following implantation of a medical device, prosthesis, or biomaterial. A brief, focused overview of events leading to the foreign body reaction is presented. The major focus of this review is on factors that modulate the interaction of macrophages and foreign body giant cells on synthetic surfaces where the chemical, physical, and morphological characteristics of the synthetic surface are considered to play a role in modulating cellular events. These events in the foreign body reaction include protein adsorption, monocyte/macrophage adhesion, macrophage fusion to form foreign body giant cells, consequences of the foreign body response on biomaterials, and cross-talk between macrophages/foreign body giant cells and inflammatory/wound healing cells. Biomaterial surface properties play an important role in modulating the foreign body reaction in the first two to four weeks following implantation of a medical device, even though the foreign body reaction at the tissue/material interface is present for the in vivo lifetime of the medical device. An understanding of the foreign body reaction is important as the foreign body reaction may impact the biocompatibility (safety) of the medical device, prosthesis, or implanted biomaterial and may significantly impact short- and long-term tissue responses with tissue-engineered constructs containing proteins, cells, and other biological components for use in tissue engineering and regenerative medicine. Our perspective has been on the inflammatory and wound healing response to implanted materials, devices, and tissue-engineered constructs. The incorporation of biological components of allogeneic or xenogeneic origin as well as stem cells into tissue-engineered or regenerative approaches opens up a myriad of other challenges. An in depth understanding of how the immune system interacts with these cells and how biomaterials or tissue-engineered constructs influence these interactions may prove pivotal to the safety, biocompatibility, and function of the device or system under consideration.
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