Clinical experience with N-butyl cyanoacrylate (Nexacryl) tissue adhesive

In situ UNIversal Orthogonal Network (UNION) bioink deposition for direct delivery of corneal stromal stem cells to corneal wounds

The scarcity of human donor corneal graft tissue worldwide available for corneal transplantation necessitates the development of alternative therapeutic strategies for treating patients with corneal blindness. Corneal stromal stem cells (CSSCs) have the potential to address this global shortage by allowing a single donor cornea to treat multiple patients. To directly deliver CSSCs to corneal defects within an engineered biomatrix, we developed a UNIversal Orthogonal Network (UNION) collagen bioink that crosslinks in situ with a bioorthogonal, covalent chemistry. This cell-gel therapy is optically transparent, stable against contraction forces exerted by CSSCs, and permissive to the efficient growth of corneal epithelial cells. Furthermore, CSSCs remain viable within the UNION collagen gel precursor solution under standard storage and transportation conditions. This approach promoted corneal transparency and re-epithelialization in a rabbit anterior lamellar keratoplasty model, indicating that the UNION collagen bioink serves effectively as an in situ-forming, suture-free therapy for delivering CSSCs to corneal wounds.

Comparative Outcomes of Single Versus Multiple Cyanoacrylate Tissue Adhesive Applications in the Management of Corneal Thinning and Perforation

PURPOSE

To compare outcomes between patients treated with a single cyanoacrylate tissue adhesive (CTA) patch for corneal thinning or perforation and those requiring multiple CTA applications.

METHODS

We conducted a single-center, comparative cohort study of patients with corneal thinning or perforation treated with either a single or multiple CTA applications in Toronto, Canada, between 2006 and 2024. Primary outcomes were the need for penetrating keratoplasty (PKP) and the best-corrected visual acuity (BCVA) at final follow-up. Associations between the number of CTA applications with baseline characteristics, perforation characteristics, and final outcomes were analyzed using univariable and multivariable logistic regression models.

RESULTS

Overall, 189 patients (median age 69.0 years; 42% female) were included, with 116 (61%) in the single CTA group and 73 (39%) in the multiple-application group (mean 2.3 ± 0.6), over a median follow-up of 4.4 months. Baseline characteristics were similar between groups. Central and paracentral corneal defects were more likely to require multiple glue applications than peripheral defects (OR = 2.92, 95% CI, 1.31-6.51, P = 0.009). No difference was observed in final BCVA between groups (median: 2.0 logarithm of the minimum angle of resolution [single] vs. 2.0 logarithm of the minimum angle of resolution [multiple]; P = 0.838). Patients receiving multiple CTA applications (48%, n = 35/73) were more likely to require PKP (OR = 2.70, 95% CI, 1.42-5.15, P = 0.003) than those treated with a single glue patch (26%, n = 30/116).

CONCLUSIONS

Multiple CTA applications were more frequently needed for central/paracentral defects and were associated with a greater likelihood of PKP. Given no significant difference in final BCVA, a conservative, stepwise management approach can be pursued without compromising long-term visual outcomes, allowing flexibility in surgical planning.

Factors Influencing Cyanoacrylate Tissue Adhesive Outcomes for Corneal Thinning and Perforation

Background and Objectives: To report the outcomes of cyanoacrylate tissue adhesive (CTA) in patients with corneal perforations and thinning. Materials and Methods: A retrospective interventional study of 83 eyes treated with CTA for corneal thinning or perforation at a single institution between 2010 and 2020. Primary endpoints leading to CTA failure, visual acuity, and surgical outcomes were evaluated. Results: At presentation, 55 (66%) had frank perforations and 28 (34%) had thinning or desmetocele. Univariate analysis showed that only multiple CTA applications were associated with CTA failure (p = 0.047). Multivariate analysis did not show any statistically significant variables associated with CTA failure. No variables were associated with the need for future surgery at 30 days or any further point. Older patients (p = 0.005), use of topical steroids before gluing (p = 0.03), corneal thinning (vs. perforation) (p = 0.02), location of pathology (p = 0.048), and multiple CTA applications (p = 0.046) were associated with worse visual outcomes in univariate analysis. Multivariate logistic regression analysis showed that older age (OR 1.05) and use of topical steroids before gluing (OR 3.84) showed higher odds, and systemic immunosuppression (OR 0.08) and single (versus multiple) CTA application (OR 0.11) showed lower odds of worse visual acuity (BCVA ≥ 20/200). The presence of an anterior chamber prior to gluing was associated with spontaneous dislocation of CTA (p = 0.015). Spontaneous dislocation versus manual removal of glue was not associated with final visual acuity (p = 0.7), nor was duration of glue on the cornea (p = 0.2). Conclusions: CTA remains a mainstay of management in patients with corneal thinning or perforation. Only multiple CTA applications were associated with CTA failure, and duration of glue on the cornea was not associated with final visual acuity.

Adhesion Mechanism, Applications, and Challenges of Ocular Tissue Adhesives

Corneal injury is prevalent in ophthalmology, with mild cases impacting vision and severe cases potentially resulting in permanent blindness. In clinical practice, standard treatments for corneal injury involve transplantation surgery combined with pharmacological therapy. However, surgical sutures exhibit several limitations, which can be overcome using tissue adhesives. With recent advances in biomedical materials, the use of ophthalmic tissue adhesives has expanded beyond wound closure, including tissue filling and drug delivery. Furthermore, the use of tissue adhesives has demonstrated promising outcomes in drug delivery, ophthalmic disease diagnosis, and biological scaffolds. This study briefly introduces common adhesion mechanisms and their applications in ophthalmology, aiming to increase interest in tissue adhesives and clinical ophthalmic treatment.

Evaluation of Cyanoacrylate Tissue Adhesive Glue Application Outcomes in Corneal Thinning and Perforation

OBJECTIVES

Corneal thinning and perforation are ocular emergencies necessitating urgent intervention to prevent visual impairment or enucleation. Cyanoacrylate tissue adhesive is frequently used to maintain globe integrity in these cases. However, gaps remain in understanding the outcomes of corneal gluing and the factors influencing its efficacy. This case series evaluates the clinical characteristics and outcomes of glue application in corneal thinning and perforation.

METHODS

A retrospective chart review was conducted on patients treated for corneal thinning and perforation at the University of Florida between January 2012 and May 2023. Demographic data, clinical history, glue application details, and posttreatment outcomes were collected and analyzed.

RESULTS

The study included 128 eyes from 125 subjects. Corneal perforation was found in 71 eyes (55.5%), mostly centrally (49.2%). The leading cause of perforation/thinning was microbial infection (45.3%). The average number of glue applications per eye was 1.66. Within 1 month, 23 patients (18.0%) required only glue reapplication, 37 (28.9%) required surgical intervention (regardless of glue reapplication), and 68 (53.1%) required no further treatment. Factors significantly linked to gluing failure (requiring surgery within 1 month) in univariate analysis included large perforation size, microbial infection, ocular surface disorder, single glue application, and indirect application via sterile drape. Multivariate analysis showed that only large perforation size was significantly associated with gluing failure.

CONCLUSION

Corneal glue application is an effective temporizing measure for corneal thinning and perforation, with multiple applications potentially providing added stability to the globe. However, the need for surgical intervention is high.

In Situ UNIversal Orthogonal Network (UNION) Bioink Deposition for Direct Delivery of Corneal Stromal Stem Cells to Corneal Wounds

The scarcity of human donor corneal graft tissue worldwide available for corneal transplantation necessitates the development of alternative therapeutic strategies for treating patients with corneal blindness. Corneal stromal stem cells (CSSCs) have the potential to address this global shortage by allowing a single donor cornea to treat multiple patients. To directly deliver CSSCs to corneal defects within an engineered biomatrix, we developed a UNIversal Orthogonal Network (UNION) collagen bioink that crosslinks in situ with a bioorthogonal, covalent chemistry. This cell-gel therapy is optically transparent, stable against contraction forces exerted by CSSCs, and permissive to the efficient growth of corneal epithelial cells. Furthermore, CSSCs remain viable within the UNION collagen gel precursor solution under standard storage and transportation conditions. This approach promoted corneal transparency and re-epithelialization in a rabbit anterior lamellar keratoplasty model, indicating that the UNION collagen bioink serves effectively as an in situ -forming, suture-free therapy for delivering CSSCs to corneal wounds. TEASER. Corneal stem cells are delivered within chemically crosslinked collagen as a transparent, regenerative biomaterial therapy.

Outcomes of N-butyl-2-Cyanoacrylate Tissue Adhesive Application in Corneal Perforation Disorders: Consecutive Case Series

INTRODUCTION

The purpose of this study was to report the success and long-term outcomes of cyanoacrylate tissue adhesive (CTA) application in the management of corneal perforation disorders.

METHODS

This retrospective case series describes the profile and outcomes of eyes that underwent CTA for corneal perforation over an 11-year period from January 2009 until January 2020 at a tertiary eye centre in the United Kingdom.

RESULTS

In total, 25 eyes underwent CTA application during the study period. Non-traumatic sterile corneal melt was responsible in more than half of the cases (56.0%; n = 14) followed by infection (32.0%; n = 8) and trauma (12.0%; n = 3). Median size of perforation was 2.0 mm (interquartile range, IQR 1.0-3.0). The most common anatomical location of corneal perforation was central (56.0%; n = 14). Ocular surface disease was seen in almost all eyes except two (92.0%; n = 23) with dry eye disease being the most common (48.0%; n = 12). Amongst 23 eyes that completed follow-up (median 27 months; IQR 9.5-46.5), single CTA application was successful in achieving intact globe in 13 (56.5%) eyes and repeat gluing sealed total of 20 (86.9%) eyes. Survival analysis showed cumulative success of 71.0% and 51.2% at 90 and 250 days, respectively. The CTA was retained in the eyes for median of 94.0 days (IQR 30.0-140.5). A total of five patients developed adverse events, including endophthalmitis (n = 2), following CTA application.

CONCLUSIONS

CTA was highly effective in sealing corneal perforations in acute setting and showed moderate long-term success. However, multiple applications are often required.

Applications of hydrogel materials in different types of corneal wounds

Severe corneal injury can lead to a decrease in light transmission and even blindness. Currently, corneal transplantation has been applied as the primary treatment for corneal blindness; however, the worldwide shortage of suitable corneal donor tissue means that a large proportion of patients have no access to corneal transplants. This situation has contributed to the rapid development of various corneal substitutes. The development and optimization of novel hydrogels that aim to replace partial or full-thickness pathological corneas have advanced in the last decade. Meanwhile, with the help of 3D bioprinting technology, hydrogel materials can be molded to a refined and controllable shape, attracting many scientists to the field of corneal reconstruction research. Although hydrogels are not yet available as a substitute for traditional clinical methods of corneal diseases, their rapid development makes us confident that they will be in the near future. We summarize the application of hydrogel materials for various types of corneal injuries frequently encountered in clinical practice, especially focusing on animal experiments and preclinical studies. Finally, we discuss the development and achievements of 3D bioprinting in the treatment of corneal injury.

Dual-crosslinked regenerative hydrogel for sutureless long-term repair of corneal defect

Corneal transplantation is the most effective clinical treatment for corneal defects, but it requires precise size of donor corneas, surgical sutures, and overcoming other technical challenges. Postoperative patients may suffer graft rejection and complications caused by sutures. Ophthalmic glues that can long-term integrate with the corneal tissue and effectively repair the focal corneal damage are highly desirable. Herein, a hybrid hydrogel consisting of porcine decellularized corneal stroma matrix (pDCSM) and methacrylated hyaluronic acid (HAMA) was developed through a non-competitive dual-crosslinking process. It can be directly filled into corneal defects with various shapes. More importantly, through formation of interpenetrating network and stable amide bonds between the hydrogel and adjacent tissue, the hydrogel manifested excellent adhesion properties to achieve suture-free repair. Meanwhile, the hybrid hydrogel not only preserved bioactive components from pDCSM, but also exhibited cornea-matching transparency, low swelling ratio, slow degradation, and enhanced mechanical properties, which was capable of withstanding superhigh intraocular pressure. The combinatorial hydrogel greatly improved the poor cell adhesion performance of HAMA, supported the viability, proliferation of corneal cells, and preservation of keratocyte phenotype. In a rabbit corneal stromal defect model, the experimental eyes treated with the hybrid hydrogel remained transparent and adhered intimately to the stroma bed with long-term retention, accelerated corneal re-epithelialization and wound healing. Giving the advantages of high bioactivity, low-cost, and good practicality, the dual-crosslinked hybrid hydrogel served effectively for long-term suture-free treatment and tissue regeneration after corneal defect.

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Double-network hydrogel contains regenerative decellularized corneal stroma matrix.

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Suture-free easy operation, high transparency, strong attachment to stroma bed.

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Long-term retention on corneal defect with excellent force and pressure resistance.

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Rapid re-epithelialization, minimal scar formation, sustained cornea regeneration.

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A functional biomaterial-based strategy for in situ corneal wound healing.

Tissue Adhesives for the Management of Corneal Perforations and Challenging Corneal Conditions

Corneal perforations are ophthalmological emergencies which can have serious and detrimental consequences, if not managed timely and appropriately. These are a significant cause of ocular morbidity and can result in decreased vision, blindness, and even loss of the eye. Corneal perforations can be managed using a range of treatment approaches, including temporary solutions such as the application of corneal glue and bandage contact lens, as well as definitive treatment such as corneal transplantation. Tissue glues/adhesives were developed as substitutes for sutures in ophthalmic surgery. Unlike sutures, these glues are associated with shorter overall surgical times and reduced inflammation, thus improving postoperative comfort without compromising wound strength. The available tissue adhesives can be broadly classified into two types: synthetic (eg, cyanoacrylate derivatives) and biological (eg, fibrin glue). Cyanoacrylate glue is chiefly used as a corneal patch to manage acute corneal perforations and improve visual outcomes. Fibrin glue can be used instead of cyanoacrylate glue in many conditions with the benefits of reduced conjunctival and corneal inflammation and reaction. Apart from this, each type of adhesive is distinct in terms of its benefits as well as limitations and is accordingly used for different indications. The present review focuses on the two main types of tissue adhesives, their applications in the management of corneal perforations, the associated complications, safety and efficacy data related to their use available in the literature and the need for newer adhesives in this field.

Surgical Management of Peripheral Ulcerative Keratitis: Update on Surgical Techniques and Their Outcome

Peripheral ulcerative keratitis (PUK) is an inflammatory, necrotic condition in the peripheral cornea which may end in corneal perforation and visual morbidity if not treated adequately. PUK can occur due to infectious or non-infectious causes. Early cases need medical therapy, both locally and systemically (for some cases). However, advanced PUK may necessitate surgical removal of inciting cause of the pathology and maintaining tectonic stability. Such surgical treatment, including corneal transplantations, may be used in an emergency setting or for visual rehabilitation following preliminary stabilization of the affected cornea. The outcome of these surgeries need to be analyzed to understand the long-term visual prognosis of such eyes. This is an attempt to analyze surgical modalities in the management of PUK and their outcomes.

Alternaria fungus growing on top of cyanoacrylate glue in a patient with perforated corneal ulcer

Purpose

To demonstrate a case where Alternaria fungus grew on top of cyanoacrylate glue used to seal a perforated corneal ulcer.

Observations

We document the clinical course of a rare case of Alternaria keratitis over the course of 6 months. Despite the purported antifungal properties of cyanoacrylate glue demonstrated in vitro, this case provides in vivo evidence that this substance can serve as a scaffold on which pathogenic fungi may grow.

Conclusion

This report demonstrates the importance of close follow up of patients with corneal glue patches in place. Ophthalmologists should continue to inspect the cornea and glue for possible development of secondary infection, particularly with concomitant contact lens and/or steroid use.

Optical coherence tomography findings of cyanoacrylate glue patch in corneal perforations

Purpose

To report a cases series of corneal perforations treated with cyanoacrylate glue patch (CGP) assessed with optical coherence tomography for monitoring corneal status in long-term follow-up examinations.

Observations

CPG was successfully used as primary treatment in three cases of corneal perforations. Spontaneous loosening or dislodging of the CPG did not occur in the follow-up. Anterior segment optical coherence tomography (AS-OCT) was performed to monitor wound healing at the site of perforation before considering the CGP removal. The presence of normal epithelium layer beneath the glue patch and stromal regeneration tissue were confirmed by AS-OCT, and glue patch was safely removed.

Conclusions and importance

The area of healing tissue beneath the CGP may not be easy to evaluate using the slit-lamp microscopy alone. AS-OCT is a useful tool in the assessment of corneal healing tissue in the presence of cyanoacrylate glue patch.

Thermosensitive gallic acid-conjugated hexanoyl glycol chitosan as a novel wound healing biomaterial

In the present study, a novel synthetic tissue adhesive material capable of sealing wounds without the use of any crosslinking agent was developed by conjugating thermosensitive hexanoyl glycol chitosan (HGC) with gallic acid (GA). The degree of N-gallylation was manipulated to prepare GA-HGCs with different GA contents. GA-HGCs demonstrated thermosensitive sol-gel transition behavior and formed irreversible hydrogels upon natural oxidation of the pyrogallol moieties in GA, possibly leading to GA-HGC crosslinks through intra/intermolecular hydrogen bonding and chemical bonds. The GA-HGC hydrogels exhibited self-healing properties, high compressive strength, strong tissue adhesive strength and biodegradability that were adjustable according to the GA content. GA-HGCs also presented excellent biocompatibility and wound healing effects. The results of in vivo wound healing efficacy studies on GA-HGC hydrogels indicated that they significantly promote wound closure and tissue regeneration by upregulating growth factors and recruiting fibroblasts compared to the untreated control group.

Mini-Descemet Stripping-Automated Endothelial Keratoplasty for Macro Corneal Perforations

PURPOSE

We present a technique that preserves good vision in paracentral macroperforations and avoids challenges of tectonic lamellar or penetrating keratoplasty in eyes with poor visual potential.

METHOD

A wet laboratory was implemented for mini-Descemet stripping endothelial keratoplasty to seal macroperforations ab interno. This included a suture support technique designed to prevent graft herniation. We also present 3 cases who were treated successfully with this technique.

RESULTS

The laboratory test confirmed that mini-Descemet stripping endothelial keratoplasty can successfully seal macroperforations without the need of large incisions. The minidisc is introduced through the perforation, and a double mattress suture prevents graft herniation. The technique allowed us to preserve 20/15 unaided vision in a case with paracentral macroperforation. It also restored eye globe integrity and achieved long-term stability in 2 cases with limbal stem-cell deficiency.

CONCLUSIONS

Mini-Descemet stripping-automated endothelial keratoplasty technique can be an alternative approach to avoid poor visual outcomes of tectonic keratoplasty in paracentral perforations. It also offers host tissue preservation in eyes with high risk of rejection for tectonic grafts.

Management of corneal perforations: An update

Corneal perforation is a potentially devastating complication that can result from numerous conditions that precipitate corneal melting. It is associated with significant morbidity and prompt intervention is necessary to prevent further complications. Causes include microbial keratitis, ocular surface disease, and autoimmune disorders and trauma. Various management options have been described in the literature to facilitate visual rehabilitation. This rview discusses the treatment options that range from temporising measures such as corneal gluing through to corneal transplantation, with decision making guided by the location, size, and underlying aetiology of the perforation.

Polyethylene Glycol-Based Synthetic Hydrogel Sealant for Filtration Bleb Leaks: An In Vivo and Histologic Study

Purpose

To evaluate the efficacy of polyethylene glycol (PEG)-based synthetic sealant for closing bleb leaks after glaucoma filtration surgery.

Methods

Tube shunt surgery that included implantation of a 22-gauge indwelling catheter and intraoperative mitomycin C was performed in the left eyes of 11 New Zealand white rabbits. Seven days postoperatively, all filtration blebs were perforated with an 18-gauge needle to create a bleb hole. In six rabbits, the holes were covered with the sealant and irradiated with blue-green light for 60 seconds; in the five control rabbits, the holes were untreated. For 3 weeks after the tube shunt surgery, the eyes were checked for bleb leaks, and the intraocular pressure (IOP) was measured in both eyes. Finally, the operated eyes were enucleated for histologic examination.

Results

The bleb leaks stopped in the eyes in which sealant was used and persisted in the other eyes. The sealant preserved the bleb function; the IOPs in these eyes were significantly (P < 0.05) lower than the right eyes that did not undergo surgery. Hematoxylin and eosin staining showed that the holes were closed and covered with conjunctival epithelial cells in the eyes in which sealant was applied; the holes were open in the control eyes. Immunohistochemical staining showed that the bleb holes in which the sealant was applied had fewer inflammatory cells.

Conclusions

The PEG sealant has the potential to seal bleb leaks effectively.

Translational Relevance

Application of the PEG sealant can be used as adjunct therapy for bleb leaks in glaucoma surgery.

Efficacy of cyanoacrylate tissue adhesive in the management of corneal thinning and perforation due to microbial keratitis

PURPOSE

Report the efficacy of cyanoacrylate tissue adhesive (CTA) application in the management of corneal thinning and perforations associated with microbial keratitis.

METHODS

A retrospective review of consecutive patients who underwent CTA application for corneal thinning and perforation secondary to microbiologically proven infectious keratitis between 2001 and 2018 at a single center. We defined successful CTA application as an intact globe without tectonic surgical intervention.

RESULTS

The cohort included 67 patients, and 37 presented with corneal perforation while 30 had corneal thinning. The perforation/thinning was central/paracentral in 43 eyes and peripheral in 23 eyes. The underlying infectious etiologies were monomicrobial in 42 cases (35 bacterial, 3 fungal, 2 viral, and 2 acanthamoeba cases) and polymicrobial in 25 cases (22 polybacterial cases and 3 cases with a combination of Gram positive bacteria and fungus). The median duration of glue retention was 29 days. The CTA success rate was 73%, 64%, and 44% at 10, 30, and 180 days, respectively. CTA application appears more successful in monomicrobial (vs. polymicrobial) and Gram positive bacterial (vs. Gram negative) keratitis but the differences are statistically non-significant. The location of perforation/thinning and the use of topical corticosteroid were not associated with CTA failure.

CONCLUSION

CTA was moderately effective in restoring globe integrity in severe corneal thinning and perforation secondary to microbial keratitis in the short term. However the majority of patients require tectonic surgical intervention within 6 months. CTA application success is not significantly associated with the location of thinning/perforation or the use of topical corticosteroid.

Bioactive Pore-Forming Bone Adhesives Facilitating Cell Ingrowth for Fracture Healing

The effectiveness of commercial bone adhesives is known to be hampered by the weak efficacy of cell ingrowth. The strategy of macropore-forming, especially bioactive macropores, holds considerable promise to circumvent this problem, thereby promoting fracture healing. Herein, a class of bioactive glass-involved macropore-embedded bone adhesives is developed, which is capable of facilitating the migration of bone-derived mesenchymal stromal cells into the adhesive layer and differentiation into osteocytes. The integration of bioactive glass-particle-encapsulated porogens in the bone adhesives is key to this approach. A robust instant bonding on the bone adhesive and a high efficiency of bone regeneration on a mouse skull are observed, both of which are vital for clinical applications and personalized surgical procedures. This work represents a general strategy to design biomaterials with high cell-ingrowth efficacy.

Outcomes of Cyanoacrylate Tissue Adhesive Application in Corneal Thinning and Perforation

PURPOSE

To report the outcomes of cyanoacrylate tissue adhesive (CTA) application in corneal thinning and perforation.

METHODS

A retrospective interventional case series of 137 patients receiving CTA for corneal thinning and perforation in 140 eyes between 2001 and 2018 at a single center was reviewed. Success rate and factors associated with glue failure were analyzed.

RESULTS

Median age of the cohort was 63 years and 69 (50%) were women. One hundred fifteen patients (84%) had at least 1 systemic condition, 46 (34%) had autoimmune diseases. Eighty-nine eyes (64%) presented with perforation and 51 (36%) with thinning. The perforation/thinning was central/paracentral in 82 eyes (59%) and peripheral in 57 eyes (41%). Median size of perforation was 3.1 mm. Causes of perforation and thinning were microbial infection in 75 (55%), sterile melt in 49 (35%), laceration in 10, and keratoprosthesis melt in 8 eyes. Median glue retention was 58 days. Success rate of glue application (defined as intact globe without surgical intervention) was 72%, 61%, and 46% at 10, 30, and 90 days after glue application, respectively. Larger size of perforation/thinning, perforation (vs. thinning), and single glue application (vs. multiple) were correlated with higher failure rate. Systemic conditions, use of topical corticosteroid, etiologies, and location of perforation/thinning were not significantly correlated with glue failure.

CONCLUSIONS

CTA application was moderately effective in stabilizing corneal perforation and thinning in the very short-term. Multiple applications are often required. Maintenance of globe integrity after glue application decreases with time and the need for surgical intervention remains high.

Ocular adhesives: Design, chemistry, crosslinking mechanisms, and applications

Closure of ocular wounds after an accident or surgery is typically performed by suturing, which is associated with numerous potential complications, including suture breakage, inflammation, secondary neovascularization, erosion to the surface and secondary infection, and astigmatism; for example, more than half of post-corneal transplant infections are due to suture related complications. Tissue adhesives provide promising substitutes for sutures in ophthalmic surgery. Ocular adhesives are not only intended to address the shortcomings of sutures, but also designed to be easy to use, and can potentially minimize post-operative complications. Herein, recent progress in the design, synthesis, and application of ocular adhesives, along with their advantages, limitations, and potential are discussed. This review covers two main classes of ocular adhesives: (1) synthetic adhesives based on cyanoacrylates, polyethylene glycol (PEG), and other synthetic polymers, and (2) adhesives based on naturally derived polymers, such as proteins and polysaccharides. In addition, different technologies to cover and protect ocular wounds such as contact bandage lenses, contact lenses coupled with novel technologies, and decellularized corneas are discussed. Continued advances in this area can help improve both patient satisfaction and clinical outcomes.

Surgical management of peripheral corneal thinning disorders

The peripheral corneal thinning disorders are associated with degenerative, autoimmune, or infective causes. Corneal thinning can subsequently affect the visual acuity either by inducing severe astigmatism or by progressive involvement of the central cornea. In addition to this, the integrity of the eye is at risk. Medical management is necessary to address the underlying inflammatory or infectious causes; however, most of the cases require surgical intervention for tectonic support or for visual rehabilitation in patients with severe astigmatism. Preoperative investigations help in mapping the corneal curvature and thickness, thereby facilitating planning of treatment. Routine corneal transplantation techniques do not yield good results in peripheral corneal thinning disorders. Various surgical modifications have been described to manage these challenging cases. We review the available literature on causes and management of peripheral corneal thinning disorders.

Biocompatible alkyl cyanoacrylates and their derivatives as bio-adhesives

Cyanoacrylate adhesives and their homologues have elicited interest over the past few decades owing to their applications in the biomedical sector, extending from tissue adhesives to scaffolds to implants to dental material and adhesives, because of their inherent biocompatibility and ability to polymerize solely with moisture, thanks to which they adhere to any substrate containing moisture such as the skin.

A Novel Tectonic Keratoplasty with Femtosecond Laser Intrastromal Lenticule for Corneal Ulcer and Perforation

BACKGROUND

Small incision refractive lenticule extraction (SMILE) is an effective laser procedure that treats myopia. This research was to describe a novel approach to treat corneal ulcer or perforation using the corneal lenticules obtained from SMILE and to evaluate the safety and effectiveness of tectonic keratoplasty with femtosecond laser intrastromal lenticule (TEKIL).

METHODS

A total of twenty patients (22 eyes) were monitored for at least 6 months and were assessed using slit lamp microscopy, optical coherence tomography, and best-corrected visual acuity (BCVA). Postoperative complications throughout the study period were recorded.

RESULTS

Corneal ulcer in 14 patients (16 eyes) and corneal perforation in six patients (6 eyes) were treated with TEKIL. The patients were ten females and ten males, with a mean age of 58.5 ± 16.3 years (range: 16-81 years). In this study, the most causes of corneal ulcer or perforation were immunologic causes (54.5%). After TEKIL procedure, global integrity was achieved in all cases. No immune rejection or perforation was detected. The mean BCVA improved from 0.17 ± 0.20 preoperatively to 0.27 ± 0.25 postoperatively at the final follow-up (t = 2.095, P = 0.052). The postoperative BCVA improved in 12 eyes (54.5%) and maintained in nine eyes (40.9%). Vision function successfully maintained in all eyes (100%). In three cases, corneal ulcers were treated by reoperation of TEKIL at 3 months after the initial surgery for the reason that the residual corneal thickness was <250 μm.

CONCLUSIONS

TEKIL seems to be an effective treatment for corneal ulcer and perforation in the condition of emergency and donor shortage.

Cyanoacrylate Tissue Adhesives

Cyanoacrylate adhesives have been available for many years. Until recently, they have been limited by their physical properties, and their popularity has been sporadic due to their incorrect and inappropriate use. A new medical-grade cyanoacrylate adhesive has been developed that has greater strength and flexibility than previous adhesives. This new formulated octylcyanoacrylate will broaden the indications for the use of cyanoacrylate adhesives and has the potential to revolutionize wound care.

Management of inflammatory corneal melt leading to central perforation in children: a retrospective study and review of literature

PURPOSE

To assess the outcome of early therapeutic penetrating keratoplasty (PKP) for corneal melt leading to perforation in children.

METHODS

Case notes of all the consecutive patients presenting with acute corneal perforation that underwent urgent therapeutic PKP between 2000 and 2010 to the practice of one of the authors, both NHS at Great Ormond Street Hospital for Children and private, were retrospectively reviewed. Onset of perforation, underlying cause, medical and surgical treatment, pre- and post-operative visual acuity, graft clarity, length of follow-up, and post-operative complications were recorded.

RESULTS

Four eyes of four consecutive patients (mean age of 9.5 years and median 8.5 years, range 4-17 years) were treated for acquired acute onset corneal perforations. There were three females and one male. Etiologies included herpes simplex keratitis secondary to immune recovery disease post bone marrow transplantation, acanthamoeba keratitis, recessive dystrophic epidermolysis bullosa, and blepharokeratoconjunctivitis with acne rosacea. Pre-operative visual acuity ranged from hand movements to 6/150. All the patients had severe anterior chamber inflammation. All eyes improved in visual acuity ranging from 6/9 to 6/18 with clear grafts at last follow-up. There was no recurrence of melt or perforation. Mean follow-up was 67 months (median 44 months).

CONCLUSION

PKP during the acute phase together with aggressive medical therapy and close follow-up may achieve good visual outcomes in children with corneal melt with perforation and should be considered. Waiting may sometimes allow the marked inflammatory response seen in children to cause irreversible structural and/or functional damage.

Comparative evaluation of cyanoacrylate and fibrin glue for muscle recession in strabismus surgery

PURPOSE

To compare the safety and efficacy of fibrin glue and cyanoacrylate glue for refixating the recessed muscle to the sclera in patients undergoing strabismus surgery.

METHODS

In this prospective, randomized, and interventional case series, there were 15 patients in each group. Two different types of glue were used for refixating the muscle to the sclera after its recession: fibrin glue (fibrin group) and cyanoacrylate glue (cyanoacrylate group). Resection was performed as usual with a 6-0 polyglactin suture. The conjunctiva was closed with the same glue that was used for muscle recession.

RESULTS

Average time required per muscle attachment was 1.48±0.694 minutes in the fibrin group and 2.42±0.584 minutes in the cyanoacrylate group. There was no significant difference in pain at all postoperative visits in both groups. Significantly more chemosis was observed in the cyanoacrylate group at postoperative 3 weeks. At all other postoperative visits, there was no significant difference in chemosis in both groups. There was significantly more conjunctival reaction in the cyanoacrylate group at 1 and 3 weeks and 3 months; the difference was highly significant at 3 months (P=.00). Total inflammatory score was significantly high in the cyanoacrylate group at 1 week, 3 weeks, and 3 months.

CONCLUSIONS

Both fibrin and cyanoacrylate glue are equally efficacious for muscle reattachment; however, fibrin glue is more biotolerant compared to cyanoacrylate glue and results in less postoperative inflammation, and is thus recommended for recession in strabismus surgery.

Simplified technique for sealing corneal perforations using a fibrin glue-assisted amniotic membrane transplant-plug

Purpose. To describe a surgical technique using amniotic membrane transplant (AMT) with fibrin glue (FG) for treating smaller corneal perforations more practically and appropriately filling the defect. Method. A patient with noninfectious central corneal perforation, in 1 mm in diameter, was treated with FG-assisted AMT-plug. An AMT was folded in on itself twice by using FG then a small piece of this FG-AMT mixture was cut to maintain an appropriate plug for the site of the corneal perforation. The FG-assisted AMT-plug was placed in the perforation area by using FG. An amniotic membrane patch was placed over the plug, which was then secured by a bandage contact lens. Result. Surgery to restore corneal stromal thickness without recurrence of perforation. Conclusion. The FG-assisted AMT-plug allowed a successful repair of 1 mm in diameter corneal perforation. This technique was easily performed, thus seeming to be a good alternative to treat corneal perforations with restoring corneal thickness.

Cyanoacrylate tissue adhesive on a polyglactin scaffold in strabismus surgery: a laboratory study

BACKGROUND

The use of cyanoacrylate tissue adhesives in strabismus surgery has been variously successful, depending primarily on achieving adequate bond strength and minimizing extraocular muscle slippage. We investigate a novel approach to this problem, involving cyanoacrylate tissue adhesive on a polyglactin 910 scaffold as a means to secure extraocular muscle to the sclera for strabismus surgery.

METHODS

In this experimental laboratory study, butyl-cyanoacrylate was used to fix a polyglactin 910 scaffold to the sclera of cadaver eyes. After allowing for polymerization, a force was applied to the mesh until the polyglactin-sclera bond failed. The maximum load (g) required for bond failure was recorded. The effects of surface area of the polyglactin 910 mesh as well as time required for cyanoacrylate tissue adhesive polymerization on bond strength were investigated.

RESULTS

All combination of variables tested, except for experiments involving polyglactin 910 mesh that is 30 mm(2) with a polymerization time of 15 seconds or 30 seconds and polyglactin 910 mesh that is 40 mm(2) with a polymerization time of 15 seconds, achieved a bond strength that was significantly greater than those forces seen in a physiologic setting (P > 0.05). Increasing area or time resulted in increasing bond strength. Area and time were found to be independent variables.

CONCLUSIONS

The cyanoacrylate tissue adhesive-derived polyglactin-sclera bond achieved a maximum load greater than those seen in a physiologic setting. Our novel approach demonstrates a clinically feasible alternative to traditional means for bonding muscle to sclera in strabismus surgery.

A simple and rapid detection of tissue adhesive-induced biochemical changes in cells and DNA using Raman spectroscopy

We demonstrate a cytotoxicity evaluation of tissue adhesive using Raman spectroscopy. This method allows for quantitative, label-free, non-invasive and rapid monitoring of the biochemical changes of cells following tissue adhesive treatment. Here, we show the biochemical property changes in mouse fibroblast L929 cells and cellular DNA following tissue adhesive (Dermabond) treatment using Raman spectroscopy. The Raman band intensities were significantly decreased when the cells were treated with Dermabond as compared to control cells. These results suggest denaturation and conformational changes in proteins and degradation of DNA related to cell death. To support these conclusions, conventional cytotoxicity assays such as WST, LIVE/DEAD, and TUNEL were carried out, and the results were in agreement with the Raman results. Thus, Raman spectroscopy analysis not only distinguishes between viable and damaged cells, but can also be used for identification and quantification of a cytotoxicity of tissue adhesive, which based on the cellular biochemical and structural changes at a molecular level. Therefore, we suggest that this method could be used for cytotoxic evaluation of tissue adhesives by rapid and sensitive detection of cellular changes.

Cyanoacrylate: a handy tissue glue in maxillofacial surgery: our experience in alexandria, egypt

Cyanoacrylate tissue glue has been widely used in different surgical applications. It is easy to apply and can save considerable time and effort. Reports including series of oral and maxillofacial cases are yet to be well documented. We report our experience using cyanoacrylate tissue glue in the head and neck region in 165 patients. We have used it for indications including orbital floor graft fixation, cleft lip and palate repair, oral dressing, skin graft fixation, nasal splinting, immobilisation of traumatised teeth, management of chyle leak during neck dissection and wound closure. We have not had any complications from using cyanoacrylate. It is found to be safe and effective in different indications it is used for without undue hazards. The role of cyanoacrylate in oral and maxillofacial surgery needs further research.

Superimposed fungal ulcer after fibrin glue sealant in infectious corneal ulcer

A healthy 27-year-old woman with a corneal ulcer underwent fibrin gluing with a bandage contact lens twice, due to an impending perforation. The ulcer lesion slowly progressed, unresponsive to topical antibiotics and amphotericin B. We removed the gluing patch and performed a corneal or scraping or biopsy with multiple amniotic membrane grafts to seal the thinned or perforated cornea. Three days after the surgery, the corneal cultures grew Fusarium, as well as Enterococcus faecalis. Three weeks after surgery, the outermost layer of amniotic membranes, serving as a temporary patch, was removed. The anterior chamber was clear without cells. The signs of infection clinically and symptomatically cleared up four weeks later. Two months after surgery, the lesion became enhanced by amniotic membranes. The use of fibrin glue in infectious keratitis should be avoided, because it not only masks the underlying lesion, but it also interferes with drug penetration into the underlying lesion.

A comparison of 2-octyl cyanoacrylate adhesives versus conventional suture materials for eyelid wound closure in rabbits

Purpose

To evaluate the clinical efficacy and histopathological tolerance of 2-octyl cyanoacrylate versus conventional suture materials for eyelid wound closure in rabbits.

Methods

We performed an experimental study on 16 eyes of eight New Zealand albino rabbits. Eyelid incisions of 15 mm were done 4mm from the upper eyelid margin in both eyes. The eyes of the rabbits were divided into two groups: eyelid incisions of the right eye were closed by a 2-octyl cyanoacrylate adhesive (group A) and eyelid incisions of the left eye were closed by 7-0 nylon sutures (group B). At 1, 2, 4, and 8 weeks after surgery, the rabbits were macroscopically examined and then sacrificed. The specimens of their eyelid tissues were stained by a hematoxylin and eosin stain and Masson-trichrome stain, and were observed under microscope.

Results

Both eyelid surgical closure methods were found to be equally efficacious in fixing the eyelids of groups A and B, and their clinical efficacy was similar. Histopathological findings of the hematoxylin and eosin stain of group A showed less inflammatory infiltration than group B at 2 weeks. There were no significant histopathological differences between the two groups at 1, 4, and 8 weeks. The degree of fibrosis of the Masson-trichrome stain was similar between the two groups at 8 weeks.

Conclusions

The 2-octyl cyanoacrylate adhesive proved to be an effective eyelid closure method and was very well tolerated by the skin surface. 2-Octyl cyanoacrylate could be used as an alternative tissue adhesive for eyelid wound closure along with conventional suture materials.