In situ generated hemostatic adhesives: From mechanisms of action to recent advances and applications.

Conventional surgical closure techniques, such as sutures, clips, or skin closure strips, may not always provide optimal wound closure and may require invasive procedures, which can result in potential post-surgical complications. As result, there is a growing demand for innovative solutions to achieve superior wound closure and improve patient outcomes. To overcome the abovementioned issues, in situ generated hemostatic adhesives/sealants have emerged as a promising alternative, offering a targeted, controllable, and minimally invasive procedure for a wide variety of medical applications. The aim of this review is to provide a comprehensive overview of the mechanisms of action and recent advances of in situ generated hemostatic adhesives, particularly protein-based, thermoresponsive, bioinspired, and photocrosslinkable formulations, as well as the design challenges that must be addressed. Overall, this review aims to enhance a comprehensive understanding of the latest advancements of in situ generated hemostatic adhesives and their mechanisms of action, with the objective of promoting further research in this field.

A Bioinspired Injectable, Adhesive, and Self-Healing Hydrogel with Dual Hybrid Network for Neural Regeneration after Spinal Cord Injury.

Hydrogel-based regenerated scaffolds show promise as a platform for neural regeneration following spinal cord injury (SCI). Nevertheless, the persistent problem of poor mechanical strength and limited integration with the host tissue still exists. In this study, a bioinspired hydrogel with highly sophisticated features for neural regeneration after SCI is developed. The hydrogel is composed of dihydroxyphenylalanine (DOPA)-grafted chitosan and a designer peptide, offering a unique set of qualities such as being injectable, having self-healing abilities, and adhering to tissues. Compared to conventional hydrogels, this hydrogel ensures a significant promotion of immune response modulation and axon regrowth while featuring synapse formation of various neurotransmitters and myelin regeneration. Subsequently, functional recoveries are enhanced, including motor function, sensory function, and particularly bladder defect repair. These positive findings demonstrate that the hydrogel has great potential as a strategy for repairing SCI. Moreover, the versatility of this strategy goes beyond neural regeneration and holds promise for tissue regeneration in other contexts. Overall, this proposed hydrogel represents an innovative and multifaceted tool for engineering structures in the biomedical field.

Adhesive and self-healing materials for central nervous system repair.

The central nervous system (CNS) has a limited ability to regenerate after a traumatic injury or a disease due to the low capacity of the neurons to re-grow and the inhibitory environment formed in situ. Current therapies include the use of drugs and rehabilitation, which do not fully restore the CNS functions and only delay the pathology progression. Tissue engineering offers a simple and versatile solution for this problem through the use of bioconstructs that promote nerve tissue repair by bridging cavity spaces. In this approach, the choice of biomaterial is crucial. Herein, we present recent advances in the design and development of adhesive and self-healing materials that support CNS healing. The adhesive materials have the advantage of promoting recovery without the use of needles or sewing, while the self-healing materials have the capacity to restore the tissue integrity without the need for external intervention. These materials can be used alone or in combination with cells and/or bioactive agents to control the inflammation, formation of free radicals, and proteases activity. We discuss the advantages and drawbacks of different systems. The remaining challenges that can bring these materials to clinical reality are also briefly presented.

A cyanoacrylate/triethyl citrate/nanosilica-based closure glue with wet-adhesion capability for treatment of superficial varicose veins.

Varicose veins in legs are common in clinics. Currently, medical adhesive-based, minimally invasive endovenous occlusion is used to treat them. However, the most common cyanoacrylate medical adhesives do not perform well when used under blood/wet conditions. In particular, poor adhesion, short curing time, and high heat release greatly limit their clinical use. In this paper, we demonstrate the use of a composite system composed of butyl-cyanoacrylate, triethyl citrate, and nanosilica that exhibits a blood/wet-adhesion capability to serve as a new sealing glue. Hydrophobic triethyl citrate groups displace boundary waters while also protecting cyanoacrylate monomers from undergoing rapid polymerization. Nanosilica increases viscosity, which contributes to in situ extrusion molding and retention. An optimal formulation, FAL-006, exhibited good physical and chemical properties in vitro. The performed additional safety assays indicated that FAL-006 has good biocompatibility. The closure efficiency of FAL-006 in vivo was evaluated in both a rat abdominal aortic closure model and in a sheep lower limb venous closure model. Taken together, these results indicate that FAL-006 exhibits promising potential for use in clinical applications. Furthermore, this study provides a new strategy for designing underwater adhesive agents for additional clinical applications, and a strategy for constructing other biomaterials needed for use under wet conditions.

In situ photo-crosslinked adhesive hydrogel loaded with mesenchymal stem cell-derived extracellular vesicles promotes diabetic wound healing.

The delayed healing of diabetic wounds is directly affected by the disturbance of wound microenvironment, resulting from persistent inflammation, insufficient angiogenesis, and impaired cell functions. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) showed considerable therapeutic potential in diabetic wound healing. However, the low retention rate of MSC-EVs at wound sites hampers their efficacy. For skin wounds exposed to the outer environment, using a hydrogel with tissue adhesiveness under a moist wound condition is a promising strategy for wound healing. In this study, we modified methacryloyl-modified gelatin (GelMA) hydrogel with catechol motifs of dopamine to fabricate a GelMA-dopamine hydrogel. EVs isolated from MSCs were applied in the synthesized GelMA-dopamine hydrogel to prepare a GelMA-dopamine-EV hydrogel. The results demonstrated that the newly formed GelMA-dopamine hydrogel possessed improved properties of softness, adhesiveness, and absorptive capacity, as well as high biocompatibility in the working concentration (15% w/v). In addition, MSC-EVs were verified to promote cell migration and angiogenesis in vitro. In the skin wound model of diabetic rats, the GelMA-dopamine-EV hydrogel exerted prominent wound healing efficacy estimated by collagen deposition, skin appendage regeneration, and the expression of IL-6, CD31, and TGF-ß. In conclusion, this combination of MSC-EVs and the modified hydrogel not only accelerates wound closure but also promotes skin structure normalization by rescuing the homeostasis of the healing microenvironment of diabetic wounds, which provides a potential approach for the treatment of diabetic wounds.

Adhesive hydrogels in osteoarthritis: from design to application.

Osteoarthritis (OA) is the most common type of degenerative joint disease which affects 7% of the global population and more than 500 million people worldwide. One research frontier is the development of hydrogels for OA treatment, which operate either as functional scaffolds of tissue engineering or as delivery vehicles of functional additives. Both approaches address the big challenge: establishing stable integration of such delivery systems or implants. Adhesive hydrogels provide possible solutions to this challenge. However, few studies have described the current advances in using adhesive hydrogel for OA treatment. This review summarizes the commonly used hydrogels with their adhesion mechanisms and components. Additionally, recognizing that OA is a complex disease involving different biological mechanisms, the bioactive therapeutic strategies are also presented. By presenting the adhesive hydrogels in an interdisciplinary way, including both the fields of chemistry and biology, this review will attempt to provide a comprehensive insight for designing novel bioadhesive systems for OA therapy.

Influence of different presentations of denture adhesives on masticatory function of complete denture wearers: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Denture adhesives improve the mastication of complete denture wearers. However, the impact of denture adhesives with different presentations on mastication remains unclear. PURPOSE: The purpose of this systematic review was to answer the focused question, "Do different presentations of denture adhesives affect the masticatory function of complete denture wearers?". MATERIAL AND METHODS: This review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six databases and the non-peer-reviewed literature were searched up to July 2021. Only clinical studies (randomized clinical trials and nonrandomized clinical trials) comparing the use of different denture adhesive presentations (cream, powder, or strips) were included, without language or follow-up restrictions. The risk of bias was assessed by using the Cochrane tools (RoB 2.0 and ROBINS-I). Masticatory performance, by using single and multiple sieves, masticatory performance with color-changing chewing gum (mixing ability), swallowing threshold (particle size and number of cycles), jaw kinematics, and occlusal force were considered. Meta-analyses were conducted to evaluate masticatory performance (single sieve) and occlusal force outcomes (α=.05), and the certainty of the evidence was determined with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) evaluations. RESULTS: Nine studies (6 randomized and 3 nonrandomized clinical trials) were included. The risk of bias was considered moderate. Meta-analyses showed no differences between cream and powder denture adhesives for masticatory performance (standard mean difference=0.02; 95% CI=-0.46 to 0.50, P=.93) or between cream and strip denture adhesives for occlusal force (mean difference=14.35; 95% CI=-11.14 to 39.84, P=.27). Similarly, in qualitative analysis, cream and powder denture adhesives' performances were similar regarding masticatory performance with color-changing chewing gum (mixing ability), occlusal force, swallowing threshold (particle size and number of cycles), and jaw kinematics (P>.05). However, for resorbed ridges, cream denture adhesive resulted in a higher masticatory performance than strip (P<.05). When comparing powder to strip denture adhesives, the occlusal force was higher in the powder group (P<.05). The certainty of evidence was very low for all evaluated outcomes. CONCLUSIONS: Different presentations of denture adhesives seem to improve the masticatory function of complete denture wearers in a similar way. However, the qualitative analysis showed that, in patients with a resorbed ridge, a cream denture adhesive may be better than strips to improve mastication, although the certainty of evidence was very low.

Efficacy and safety of miconazole muco-adhesive tablet versus itraconazole in oropharyngeal candidiasis: A randomized, multi-centered, double-blind, phase 3 trial.

Oropharyngeal candidiasis (OPC) is an opportunistic infection treated with anti-fungal agents. Herein, we evaluate the efficacy and safety of miconazole buccal tablets (MBT) and itraconazole capsules in the localized treatment of patients with OPC. In this multi-centered, double-blinded, phase III trial (CTR20130414), both males and non-pregnant females (≥18 years) with OPC were randomized (1:1) to MBT plus placebo (experimental group) or itraconazole capsules plus placebo (control group). The primary endpoint was clinical cure at the end-of-treatment period [visit 4 (V4)] while secondary endpoints were clinical remission rates, partial remission rates, mycological cure, clinical relapse, and adverse events (AEs). All endpoints were statistically analyzed in both the full analysis set (FAS) and per-protocol (PP) set. A total of 431 (experimental: 216; control: 215) subjects were included. At V4, in the FAS set, the clinical cure was achieved in 68% and 59% patients in experimental and control groups, respectively with a treatment difference of 9% [95% confidence interval (CI): -1,19; P < .001] demonstrating non-inferiority of MBT over itraconazole. At V4, mycological cure rates were 68.2% and 42.0% in the experimental group and control groups (P < .001), respectively in FAS. The relapse rates were 5.4% and 6.6%, respectively, in the experimental and control groups. A total of 210 patients experienced AEs during treatment with 47.7% in the experimental group and 49.8% in the control group with no deaths. This study demonstrated that once-daily treatment with MBT was non-inferior to itraconazole with higher mycological cure rates and was tolerable with mild AE in patients with OPC.

Miconazole is an antifungal drug against certain types of fungus or yeast infections. In this study, we showed that treatment with once-daily miconazole buccal tablets was as effective as systemic itraconazole capsules in Chinese patients infected by oropharyngeal candidiasis with minimum side effects.

Abalone-Inspired Adhesive and Photo-Responsive Microparticle Delivery Systems for Periodontal Drug Therapy.

Antibiotics provide promising strategies for treating periodontitis, while their delivery and controllable release with desired oral retention remain challenging. Here, inspired by the unique suction-cup structures of abalones, a novel adhesive and photo-responsive microparticle (MP) delivery system is developed to treat periodontitis through microfluidic electrospray technology. Such MPs are generated by quickly ionic cross-linking of sodium alginate together with photo-curing of poly(ethylene glycol) diacrylate of the distorted microfluidic droplets during their high-speed dropping into calcium chloride solution. Attributing to their unique concave structures, the abalone-inspired MPs exhibit desired underwater adhesion ability and stability under running water. In addition, due to the loading of antibiotics minocycline hydrochloride and near-infrared (NIR)-responsive black phosphorus during their fabrication, the resultant MPs can not only eradicate bacteria directly, but also realize a controllable and effective drug release upon NIR irradiation. Based on these features, it is demonstrated from in vivo periodontitis that the abalone-inspired MPs are firmly adhesive and can controlled-release drugs on the tooth, and thus have outstanding antibacterial efficacy against Porphyromonas gingivalis. These results indicate the particular values of the abalone-inspired MPs for oral-related disease treatment.

The Effect of Hyperosmolar Water-Soluble Contrast for the Management of Adhesive Small Bowel Obstruction: A Systematic Review and Meta-Analysis.

OBJECTIVE: To better understand the efficacy of water-soluble contrast (WSC) in the treatment of adhesive small bowel obstruction (SBO). BACKGROUND: Guidelines recommend using WSC to treat adhesive SBO nonoperatively by acting as a cathartic agent. The evidence supporting this practice is mixed. METHODS: A systematic review and meta-analysis of published articles describing the effect of WSC compared with control treatments was performed for the period of January 1, 1990 to November 1, 2021. Study quality was assessed using the Cochrane risk-of-bias and the Newcastle-Ottawa tools. The therapeutic effect of WSC was assessed by operative rates and hospital length of stay (HLOS) in nonsurgical patients. RESULTS: The initial search yielded 4879 articles, of which, 28 were selected for full text review. We identified 11 eligible randomized controlled trials (RCTs) which included 817 patients and 9 observational studies of 3944 patients. HLOS in nonsurgical patients decreased by 1.95 days (95% confidence interval: 0.56-3.3) in the RCTs and could not be assessed in the observational studies. WSC did not significantly affect operative rates in the RCTs (19.8% vs. 21.4%) but did reduce rates in the observational studies (11% vs. 16%, risk ratio: 0.56, 95% confidence interval: 0.39-0.82). CONCLUSION: WSC studies may reduce HLOS for patients who have SBO and do not require surgery. However, the current literature is heterogenous with considerable design limitations. High-quality RCTs are needed using standardized protocols to determine the full benefit of WSC for the management of SBO.

5-ALA loaded self-adhesive patch-PDT is effective and safe in the treatment of actinic keratoses on hands and arms.

Photodynamic therapy (PDT) with 5-aminolevulinic acid hydrochloride (ALA) is an established method for the management of AK. PD P 506 A (brand name Alacare®) is an approved medicinal product for the treatment of AK located on scalp and face. It is a self-adhesive, light-proof patch loaded with 5-ALA HCl and was developed for easy handling. AK located on arms, hands or trunk do not respond as well to ALA-PDT as AK lesions on the head do. It has been reported that occlusion during ALA incubation can improve clinical outcome after ALA-PDT for AK on hands and arms. We present the results of a first explorative pilot study involving 20 participants with a total of 145 treated (122 evaluable) AK lesions. The trial investigated the conduct of two ALA-PDTs within 1-2 weeks and involved all severity grades of AK. The model-based percentage of complete clearance on lesion-basis was estimated being 78.0% (95%-CI: [64.6%, 87.3%]), and the by-participant calculation (patient-based clearance) led to similar results (78.7% with a 95%-CI of [67.0%, 90.3%]). The treatment was well tolerated. Local reactions during ALA patch incubation were rare whereas nearly all patients showed the expected reactions during or after the illumination, primarily erythema and pain. The study results indicate that two PD P 506 A-PDT sessions 1-2 weeks apart are an efficacious treatment for AK on hands and arms. Especially mild but also moderate lesions responded very well to PDT treatment involving ALA incubation under occlusion.

Endoscopic submucosal dissection-based suture combined with medical adhesive for complicated tuberculous bronchoesophageal fistula: a case report.

Tuberculous bronchoesophageal fistula is a rare complication of tuberculosis. Herein, we report the case of a woman in her late 60s with a choking cough for more than 1 month. Iohexol esophagography revealed a fistulous communication between the esophagus and the right principal bronchus, and gastroscopy documented a fistulous orifice in the esophagus. Endoscopic closure with metal clips failed, and other treatment options, such as extended conservative treatment, covered self-expandable metal stents, and over-the-scope clips were rejected by the patient. Therefore, a combined therapy, endoscopic submucosal dissection-based suture combined with medical adhesive, was performed. Follow-up iohexol esophagography and gastroscopy confirmed fistula closure. During 1 year of follow-up after discharge, the bronchoesophageal fistula did not recur. Endoscopic submucosal dissection-based suture combined with medical adhesive appears to be a practical and feasible solution to complicated tuberculous bronchoesophageal fistula.

Treatment of Non-Infectious Corneal Injury: Review of Diagnostic Agents, Therapeutic Medications, and Future Targets.

Corneal injuries can occur secondary to traumatic, chemical, inflammatory, metabolic, autoimmune, and iatrogenic causes. Ocular infection may frequently occur concurrent to corneal injury; however, antimicrobial agents are excluded from this present review. While practitioners may primarily rely on clinical examination techniques to assess these injuries, several pharmacological agents, such as fluorescein, lissamine green, and rose bengal, can be used to formulate a diagnosis and develop effective treatment strategies. Practitioners may choose from several analgesic medications to help with patient comfort without risking further injury or delaying ocular healing. Atropine, cyclopentolate, scopolamine, and homatropine are among the most frequently used medications for this purpose. Additional topical analgesic agents may be used judiciously to augment patient comfort to facilitate diagnosis. Steroidal anti-inflammatory agents are frequently used as part of the therapeutic regimen. A variety of commonly used agents, including prednisolone acetate, loteprednol, difluprednate, dexamethasone, fluorometholone, and methylprednisolone are discussed. While these medications are effective for controlling ocular inflammation, side effects, such as elevated intraocular pressure and cataract formation, must be monitored by clinicians. Non-steroidal medications, such as ketorolac, bromfenac, nepafenac, and diclofenac, are additionally used for their efficacy in controlling ocular inflammation without incurring side effects seen with steroids. However, these agents have their own respective side effects, warranting close monitoring by clinicians. Additionally, ophthalmologists routinely employ several agents in an off-label manner for supplementary control of inflammation and treatment of corneal injuries. Patients with corneal injuries not infrequently have significant ocular surface disease, either as a concurrent pathology or as an exacerbation of previously existing disease. Several agents used in the management of ocular surface disease have also been found to be useful as part of the therapeutic armamentarium for treatment of corneal injuries. For example, several antibiotics, such as doxycycline and macrolides, have been used for their anti-inflammatory effects on specific cytokines that are upregulated during acute injuries. There has been a recent wave of interest in amniotic membrane therapies (AMTs), including topical, cryopreserved and dehydrated variants. AMT is particularly effective in ocular injuries with violation of corneal surface integrity due to its ability to promote re-epithelialization of the corneal epithelium. Blood-based therapies, including autologous serum tears, plasma-enriched growth factor eyedrops and autologous blood drops, have additionally been explored in small case series for effectiveness in challenging and recalcitrant cases. Protection of the ocular surface is also a vital component in the treatment of corneal injuries. Temporary protective methods, such as bandage contact lenses and mechanical closure of the eyelids (tarsorrhaphy) can be particularly helpful in selective cases. Glue therapies, including biologic and non-biologic variants, can also be used in cases of severe injury and risk of corneal perforation. Finally, there are a variety of recently introduced and in-development agents that may be used as adjuvant therapies in challenging patient populations. Neurotrophic corneal disease may occur as a result of severe or chronic injury. In such cases, recombinant human nerve growth factor (cenegermin), topical insulin, and several other novel agents may be an alternate and effective option for clinicians to consider.

A Universal and Reversible Wet Adhesive via Straightforward Aqueous Self-Assembly of Polyethylenimine and Polyoxometalate.

The excellent adhesion of mussels under wet conditions has inspired the development of numerous catechol-based wet adhesives. Nevertheless, the performance of catechol-based wet adhesive suffers from the sensitivity toward temperature, pH, or oxidation stimuli. Therefore, it is of great significance to develop non-catechol-based wet adhesives to fully recapitulate nature's dynamic function. Herein, a novel type of non-catechol-based wet adhesive is reported, which is readily formed by self-assembly of commercially available branched polyethylenimine and phosphotungstic acid in aqueous solution through the combination of electrostatic interaction and hydrogen bonding. This wet adhesive shows reversible, tunable, and strong adhesion on diverse substrates and further exhibits high efficacy in promoting biological wound healing. During the healing of the wound, the as-prepared wet adhesive also possesses inherent antimicrobial properties, thus avoiding inflammations and infections due to microorganism accumulation.

Using a novel breathable silicone adhesive (Sil2 technology) in stoma appliances to improve peristomal skin health: answering the key questions.

Fiona Le Ber answers some of the questions that stoma care nurses may have regarding this novel silicone adhesive based technology, which helps to avoid medical adhesive related skin injury (MARSI) and moisture-associated skin damage (MASD). Whereas hydrocolloid stoma appliances absorb moisture, this has a non-absorptive method of moisture management that prevents peristomal skin becoming damp and excoriated.

Middle Meningeal Artery Embolization Using Combined Particle Embolization and n-BCA with the Dextrose 5% in Water Push Technique for Chronic Subdural Hematomas: A Prospective Safety and Feasibility Study.

BACKGROUND AND PURPOSE: Embolization of the middle meningeal artery for treatment of refractory or recurrent chronic subdural hematomas has gained momentum during the past few years. Little has been reported on the use of the n-BCA liquid embolic system for middle meningeal artery embolization. We present the technical feasibility of using diluted n-BCA for middle meningeal artery embolization. MATERIALS AND METHODS: We sought to examine the safety and technical feasibility of the diluted n-BCA liquid embolic system for middle meningeal artery embolization. Patients with chronic refractory or recurrent subdural hematomas were prospectively enrolled from September 2019 to June 2020. The primary outcome was the safety and technical feasibility of the use of diluted n-BCA for embolization of the middle meningeal artery. The secondary end point was the efficacy in reducing hematoma volume. RESULTS: A total of 16 patients were prospectively enrolled. Concomitant burr-hole craniotomies were performed in 12 of the 16 patients. Two patients required an operation following middle meningeal artery embolization for persistent symptoms. The primary end point was met in 100% of cases in which there were no intra- or postprocedural complications. Distal penetration of the middle meningeal artery branches was achieved in all the enrolled cases. A 7-day post-middle meningeal artery embolization follow-up head CT demonstrated improvement (>50% reduction in subdural hematoma volume) in 9/15 (60%) patients, with 6/15 (40%) showing an unchanged or stable subdural hematoma. At day 21, available CT scans demonstrated substantial further improvement (>75% reduction in subdural hematoma volume). CONCLUSIONS: Embolization of the middle meningeal artery using diluted n-BCA and ethiodized oil (1:6) is safe and feasible from a technical standpoint. The use of a dextrose 5% bolus improves distal penetration of the glue.

Glue versus mechanical mesh fixation in laparoscopic inguinal hernia repair: meta-analysis and trial sequential analysis of randomized clinical trials.

BACKGROUND: The optimal choice for mesh fixation in laparoscopic inguinal hernia repair (LIHR) has not been well established. This review compared the effects of glue versus mechanical mesh fixation in LIHR on incidence of chronic postoperative inguinal pain (CPIP) and other secondary outcomes, including acute pain, seroma, haematoma, hernia recurrence and other postoperative complications. METHODS: A systematic review of English/non-English studies using MEDLINE, the Cochrane Library, OpenGrey, OpenThesis and Web of Science, and searching bibliographies of included studies was completed. Search terms included laparoscopic, hernia, fibrin glue, Tisseel, Tissucol, cyanoacrylate, Glubran and Liquiband. Only RCTs comparing mechanical with glue-based fixation in adult patients (aged over 18 years) that examined CPIP were included. Two authors independently completed risk-of-bias assessment and data extraction against predefined data fields. All pooled analyses were computed using a random-effects model. RESULTS: Fifteen RCTs met the inclusion criteria; 2777 hernias among 2109 patients were assessed. The incidence of CPIP was reduced with use of glue-based fixation (risk ratio (RR) 0.36, 95 per cent c.i. 0.19 to 0.69; P = 0.002), with moderate heterogeneity that disappeared with sensitivity analysis (8 d.f.) for patient-blinded studies (RR 0.43, 0.27 to 0.86). Trial sequential analysis provided evidence for a relative risk reduction of at least 25 per cent. The incidence of haeamtoma was reduced by using glue-based fixation (RR 0.29, 0.10 to 0.82; P = 0.02) with no significant effects on seroma formation or hernia recurrence (RR 1.07, 0.46 to 2.47; P = 0.88). CONCLUSION: Glue-based mesh fixation appears to reduce the incidence of CPIP and haematoma after LIHR compared with mechanical fixation, with comparable recurrence rates.

Contribution of Interventional Radiologist in the Management of Pseudoaneurysm and Neck Hemorrhages in COVID-19 patients.

Patients with severe coronavirus disease 2019 (COVID-19) may have endothelial inflammation, pseudoaneurysm, and an increasing risk of bleeding, especially during surgical procedures. In this article, we reported 2 cases of COVID-19 patients with neck vascular lesions. The first patient had pseudoaneurysm of the cricothyroid artery, which was treated by percutaneous glue injection through ultrasonography guidance. The second patient presented lateral neck hematoma in front of the left superior thyroid artery, which was managed by coil endovascular embolization. In the context of pandemic, the management of vascular lesions may be performed through interventional radiological procedures that may reduce the risk of virus aerosolization and health care provider contamination.

Gelatin-Poly (γ-Glutamic Acid) Hydrogel as a Potential Adhesive for Repair of Intervertebral Disc Annulus Fibrosus: Evaluation of Cytocompatibility and Degradability.

STUDY DESIGN: An in vitro experimental study testing a Gelatin-poly (γ-glutamic acid) hydrogel for disc repair. OBJECTIVE: To evaluate the cytocompatibility and degradability of the above mentioned hydrogel for intervertebral disc annular fibrosis (AF) repair. SUMMARY OF BACKGROUND DATA: No repair strategies for correcting annular defects in lumbar discectomy have been clinically well recognized. Exogenous supplementation of regenerative materials to fill defects is a minimally invasive way to restore compromised mechanical properties. The injected materials, most commonly gelatin-based materials with cross-linking agents, serve as sealants and as a scaffold for incorporating biomaterials for augmentation. However, cytotoxicity of hydrogel crosslinking agents is of concern in developing viable materials. METHODS: This in vitro experimental study evaluated a newly developed gelatin-based hydrogel for intervertebral disc AF repair. Mechanical strength was augmented by γ-PGA, and 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) was used for material crosslinking. Isolated bovine tail intervertebral discs (IVDs) were used to test the hydrogel, and hydrogel surface monolayer AF cell culture was used to investigate efficacy in hydrogel constructs of different EDC concentrations. Cell metabolic activity was evaluated with Alamar blue assay, cell viability assay with live/dead stain, and sulfated glycosaminoglycan (GAG) and double strain DNA were quantified to evaluate proliferation of implanted cells and synthesis of extracellular matrix (ECM) proteins. RESULTS: EDC concentrations from 10 to 40 mM resulted in significant decreases in AF cell proliferation without obvious influence on cell viability. Higher EDC concentrations resulted in decreased percentage of Alamar blue reduction and GAG and DNA concentration, but did not affect GAG/DNA and live-dead ratios. Degradation tests revealed that higher EDC concentrations decreased the hydrogel degradation rate. CONCLUSION: The developed gelatin-poly (γ-PGA) hydrogel with 20 mM EDC concentration provides an effective gap-filling biomaterial with good cytocompatibility, suggesting substantial promise for use as a sealant for small AF defects.Level of Evidence: N/A.