Advances in the use of adhesives in ophthalmology

Application of Convergent Science and Technology toward Ocular Disease Treatment

Eyes are one of the main critical organs of the body that provide our brain with the most information about the surrounding environment. Disturbance in the activity of this informational organ, resulting from different ocular diseases, could affect the quality of life, so finding appropriate methods for treating ocular disease has attracted lots of attention. This is especially due to the ineffectiveness of the conventional therapeutic method to deliver drugs into the interior parts of the eye, and the also presence of barriers such as tear film, blood-ocular, and blood-retina barriers. Recently, some novel techniques, such as different types of contact lenses, micro and nanoneedles and in situ gels, have been introduced which can overcome the previously mentioned barriers. These novel techniques could enhance the bioavailability of therapeutic components inside the eyes, deliver them to the posterior side of the eyes, release them in a controlled manner, and reduce the side effects of previous methods (such as eye drops). Accordingly, this review paper aims to summarize some of the evidence on the effectiveness of these new techniques for treating ocular disease, their preclinical and clinical progression, current limitations, and future perspectives.

Cyanoacrylate Tissue Adhesive for the Treatment of Corneal Thinning and Perforations: A Multicenter Study

PURPOSE

To examine the outcomes of cyanoacrylate tissue adhesive (CTA) application for impending or frank corneal perforations and assess for predictors of treatment response.

METHODS

A multicenter cohort study was conducted to assess the clinical outcomes of adult patients who underwent CTA gluing for impending or frank corneal perforations between 2013 and 2018. The primary outcome was the proportion of successful CTA applications, defined as tectonic stability of the globe without subsequent keratoplasty (KP). Secondary outcomes included visual acuity and success of subsequent surgical interventions, if performed.

RESULTS

Fifty-three eyes of 52 patients were included in this study [56% women; mean age at presentation 70 ± 13 years; median length of follow-up of 387 days (interquartile range: 191-704)]. Medical comorbidities were present in 62% of patients. The most common etiologies for perforations included infections (43%) and Sjogren disease (9%). Of the CTA-treated eyes, 22% had a complete resolution of the corneal lesion. Fifty-four percent of patients underwent KP. Longer duration of CTA treatment was associated with CTA success (P = 0.04). For patients requiring KP, 71% were successful and 29% failed. There is no significant difference in the median time delay between patients with successful and failed KPs (P = 0.4).

CONCLUSIONS

CTA may be considered a stand-alone treatment for corneal perforations. It yielded a success rate of 22%. Failed CTA treatment occurred quickly, largely because of the severity of presentation. In cases requiring KP, the delay between glue application and surgery did not influence the PK success.

Adhesive Tissue Engineered Scaffolds: Mechanisms and Applications

A variety of suture and bioglue techniques are conventionally used to secure engineered scaffold systems onto the target tissues. These techniques, however, confront several obstacles including secondary damages, cytotoxicity, insufficient adhesion strength, improper degradation rate, and possible allergic reactions. Adhesive tissue engineering scaffolds (ATESs) can circumvent these limitations by introducing their intrinsic tissue adhesion ability. This article highlights the significance of ATESs, reviews their key characteristics and requirements, and explores various mechanisms of action to secure the scaffold onto the tissue. We discuss the current applications of advanced ATES products in various fields of tissue engineering, together with some of the key challenges for each specific field. Strategies for qualitative and quantitative assessment of adhesive properties of scaffolds are presented. Furthermore, we highlight the future prospective in the development of advanced ATES systems for regenerative medicine therapies.

Intracorneal scleral patch supported cyanoacrylate application for corneal perforations secondary to rheumatoid arthritis

Purpose:

To describe a new technique of intracorneal scleral patch (ICSP) supported cyanoacrylate tissue adhesive (CTA) application in corneal perforations, greater than 3.0 mm secondary to rheumatoid arthritis (RA).

Methods:

This Prospective, non-randomized, non-comparative, interventional series included 14 eyes (14 patients). All patients had corneal perforations sized 3.5 to 4.5 mm due to RA, which were treated with ICSP supported CTA application. A partial thickness scleral patch 1.0 mm larger than diameter of corneal perforation was prepared. A lamellar corneal pocket 0.5 mm all around the corneal perforation was created. The partial thickness scleral patch was placed in the corneal perforation site and the edge was fitted into the lamellar intracorneal pocket. A minimum quantity of CTA was applied on the scleral patch to seal the perforation.

Results:

The corneal perforations healed in 14 eyes (100%) in a mean 7.71 ± 1.14 (range, 6–9) weeks. One eye (7.14%) had inadvertent extrusion of ICSP due to premature removal of CTA but, Seidel's test was negative, and the corneal epithelial defect healed with BCL alone. One eye each (7.14%) developed steroid induced cataract and glaucoma. None of eyes developed infective keratitis, re-opening of corneal perforation (necessitating repeat procedure) or enlargement of corneal perforation requiring penetrating keratoplasty (PKP).

Conclusion:

ICSP supported CTA application is a successful alternative option to emergency PKP in treating corneal perforations sized 3.5 to 4.5 mm with associated RA.

SUTURELESS CLOSURE OF 23- AND 25-GAUGE LEAKING SCLEROTOMIES WITH THE SCLERAL NEEDLING TECHNIQUE

PURPOSE

To describe and evaluate the efficacy of a novel technique, scleral needling (SN), for securing 23- and 25-gauge leaking sclerotomies in microincision vitrectomy surgery.

METHODS

A retrospective comparative review of consecutive cases of 23- and 25-gauge pars plana vitrectomy performed by a single vitreoretinal surgeon before the introduction of the SN technique (pre-SN; November 2016 to January 2017) and after the introduction of the SN technique (post-SN; November 2017 to January 2018) was conducted. The SN technique was implemented as an alternative to suturing, using a 30-gauge needle inserted perpendicularly through the full thickness of the sclera adjacent to the scleral opening, with the needle then immediately removed and sclerotomy closure confirmed.

RESULTS

A total of 203 eyes, 105 from pre-SN and 98 from post-SN, were included in the study. The number of eyes requiring suture closure was significantly reduced from 39% in the pre-SN group to 2% in the post-SN group (P < 0.001). The mean postoperative intraocular pressure and incidence of hypotony on Days 1 to 2, Days 3 to 20, and Days 21 to 50 was not significantly different between the pre-SN and post-SN groups. No major complications associated with the SN technique were noted during the study period.

CONCLUSION

The SN technique is a safe and simple method for effectively securing leaking sclerotomies in microincision vitrectomy surgery.

Surgical Treatment of Massive Teratoma of the Orbit

Orbital location of teratoma is extremely rare. The differential diagnosis can be difficult and they may be mistaken for other tumors as they may have both cystic and solid areas. The authors report a case of a 7-day-old neonate with a massive congenital orbital teratoma in which it was decided to apply a surgical technique that involves the aspiration of the cystic fluid, the subsequent infusion of fibrin glue, and the radical excision. The definitive histological examination reported a diagnosis of trifillic cystic teratoma. At fourth year of follow up the patient is free from disease.

Comparison and application of commercially available fibrin sealants in ophthalmology

Fibrin glues carry many advantages over traditional suture as a tissue adhesive and have been increasingly used in a variety of ophthalmic procedures over the past 15 years. Several fibrin sealants are commercially available worldwide, each of which differs slightly in its composition and mechanism of delivery. The focus of our review is to briefly discuss the reported uses of fibrin in ophthalmic surgery and provide a broad overview of the properties associated with each commercially available fibrin sealant.

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.

Hydration of small leaking corneal perforations with cefuroxime

PURPOSE

To describe a new technique for sealing small corneal perforations after penetrating trauma.

METHODS

Corneal perforations in six eyes were sealed using a stromal cefuroxime hydration technique. This technique is identical to the current method used to seal leaking incisions upon completion of cataract surgery except for the use of cefuroxime instead of balanced salt solution. Additionally, cefuroxime was intentionally injected into the anterior chamber. A therapeutic contact lens was used after the hydration. Comparison was made in eight eyes with small traumatic corneal perforation that was sealed using therapeutic contact lenses without hydration.

RESULTS

This novel technique was applied in six cases, with leakage stopping immediately following hydration in each of these eyes. In cases presenting with a shallow or flat anterior chamber, this maneuver produced immediate reformation of the chamber. Of note, the corneal scars after hydration were minimal with little effect on visual acuity. When compared to eyes with small corneal perforations which were sealed with therapeutic contact lenses without hydration, all cases that were hydrated with cefuroxime were sealed immediately, as opposed to cases treated without hydration. Furthermore, the eyes that underwent hydration with cefuroxime had a worse average visual acuity on admission, a better average visual acuity 1 month post-trauma, and a shorter average length of hospitalization.

CONCLUSIONS

This new technique offers five major advantages: (1) Immediate sealing of the corneal perforation is achieved. (2) Definitive treatment can be achieved at the slit lamp. (3) Since neither stitches nor glue is applied, healing is achieved with minimal scarring and discomfort. (4) Little equipment is required. (5) Injection of cefuroxime into the anterior chamber provides prophylaxis against infection.

Clinical outcome observation of the embolization of orbital vascular malformation with medical glue under direct intra-operative view

Background

Orbital vascular malformation often encircles normal tissue with ill-defined borders. It is easy to bleed during resection operation, making surgical treatment difficult and lesions hard to be removed completely. In this study we aimed to summarize the treatment outcomes by embolizing orbital vascular malformation with intraoperative intracavitary injection of medical glue .

Methods

A retrospective observational and cross-sectional case series study enrolled 31 patients (male = 9, female = 22) with orbital vascular malformations, who were treated from March 2008 to September 2017 at our institution. The clinical features, operation records, pathological reports and follow-up data were analyzed.

Results

The location of vascular malformations involved intraorbital (14 cases), superficial area of eyelid and/or face (7 cases), both intraorbital and superficial area (10 cases). Imaging examination showed a solitary mass with regular shape in 8 cases and a space occupying lesion with irregular shape and ill-defined margins in 23 cases. There were 9 cases had optic nerve involved. Surgical debulkling were performed via skin incision on the mass surface (5 cases), lateral orbitotomy (2 cases), and anterior orbitotomy (24 cases). During the operation, lesions were partly exposed and injected with medical glue. The amount of injected glue was 0.25 ml to 2.5 ml in divided doses. The lesions and remnant glue were removed after the glue had turned hard. The whole procedure caused less bleeding and was easier performing than usual. Topical skin aseptic inflammation took place on the same side of the superficial eyelid lesions in 3 cases. One patient suffered from sudden central retinal artery embolism on the third day post operation. With timely rescue and appropriate procedure, visual acuity recovered to 20/32. There were no recurrences in 29 cases.

Conclusions

Embolization of orbital vascular malformation with medical glue intraoperatively made it easy to control hemorrhage. Surgeons should be careful with glue application methods in order to avoid complications.

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.

Polyethylene Glycol-Based Synthetic Hydrogel Sealant for Closing Vitrectomy Wounds: An In Vivo and Histological Study

Purpose

We conducted an in vivo study using Dutch pigmented rabbit eyes to test the usefulness of polyethylene glycol (PEG) sealant for the closure of sutureless sclerotomies in microincisional vitrectomy surgery (MIVS).

Methods

Three-port, 23-gauge vitrectomy was performed on rabbit eyes. After air leakage was confirmed by the application of 0.625% povidone–iodine at the sclerotomy site, PEG sealant was subconjunctivally injected using a 27-gauge needle through conjunctival incisions to cover the sclerotomy wounds, following which it was polymerized by the application of xenon light for 60 seconds. Ophthalmological examinations and intraocular pressure measurements were conducted the day before and 1, 3, 5, and 7 days after surgery. The eyes were enucleated for histological evaluation 7 days after surgery.

Results

PEG sealant was rapidly polymerized by the application of xenon light after subconjunctival injection, and it firmly sealed the sclerotomies without air leakage, as confirmed by povidone–iodine dropping, in all cases. Conjunctival and scleral wounds closed with PEG sealant were successfully attached and remained intact till the end of the follow-up period. There was no sign of postoperative hypotony or infection in any eye, and no adverse effects of PEG sealant were found. In histological examination, linear scar formation and eosinophilic staining of collagen fibers were observed at the sclerotomy sites, while the sclerotomy tunnels appeared tightly closed.

Conclusions

PEG sealant can be useful for the closure of sutureless 23-gauge vitrectomy incisions in rabbits.

Translational Relevance

The PEG sealant may become an effective option for closing vitrectomy incisions including pediatric cases.

Minimally Invasive Pterygium Surgery: Sutureless Excision with Amniotic Membrane and Hydrogel Sealant

Purpose

To describe a novel technique for sutureless pterygium surgery using ReSure^® tissue sealant.

Methods

In this retrospective observational case series, we describe a modified procedure for pterygium excision followed by amniotic membrane transplant (AMT) adhered to the corneal and conjunctival defects using ReSure tissue sealant.

Results

Nine eyes of seven patients (age range: 28–80 years, 4 females and 3 males) underwent pterygium removal with AMT followed by adherence of tissue to the conjunctival edges with ReSure. No issues with transplant dislocation or failure and no intra- or postoperative complications were noted. No recurrences were noted during the follow-up period.

Conclusion

ReSure may be considered as a potential sealant to adhere AMT to defective corneal and conjunctival tissues in sutureless pterygium surgery.

Evaluation of mechanical closure resistance of sutureless vitrectomy sclerotomies after conjunctival cauterization with bipolar diathermy forceps

BACKGROUND

Suturing is the most widely used technique to close leaking sclerotomies after transconjunctival sutureless vitrectomy (TSV). However, with the aim of avoiding the disadvantages caused by conjunctival stitches, there have been described other closure techniques, such as the cauterization of the conjunctiva placed over the incisions. To continue advancing knowledge of the incisional occlusion effect achieved by conjunctival diathermy, it would be also interesting to study the wound closure resistance obtained under intraocular pressure (IOP) changes, given that in the early postoperative period eyes are subjected to pressure stress. In our study, we compare the mechanical resistance observed in sclerotomies treated with bipolar diathermy after TSV compared to that found in incisions in which cauterization was not performed.

METHODS

This was an experimental, randomized, and observer-masked study in which 23-gauge TSV was performed in 80 cadaveric pig eyes. Once each vitrectomy was finished, cauterization was performed with bipolar diathermy forceps on the conjunctiva placed over one of the superior sclerotomy sites; no maneuver was performed over the other superior incision. IOP was gradually increased by means of the vitrectomy system (Accurus; Alcon Laboratories, TX) until one of the superior sclerotomies opened, allowing internal ocular solution to escape.

RESULTS

In 35 % of cases (28 of 80 eyes), sclerotomies subjected to diathermy allowed intraocular fluid escape first (p = 0.01). When comparing opening pressure values, cauterized incisions leaked at significantly higher pressure levels than those in which diathermy was not applied (p < 0.001).

CONCLUSIONS

Bipolar diathermy on sutureless sclerotomies has demonstrated to be, in our experimental model, an effective method for increasing the sclerotomy closure resistance. Although its use in vitrectomized eyes has previously been described, our study is the first to analyze the response of cauterized sclerotomies to IOP increases.

[Peripheral corneal melting syndrome in psoriatic arthritis treated with adalimumab]

Peripheral corneal melting syndrome is a rare immune condition characterized by marginal corneal thinning and sometimes perforation. It is associated with rheumatic and non-rheumatic diseases. Few cases of peripheral corneal melting have been reported in patients with psoriasis. The pathogenesis is not fully understood but metalloproteinases may play a pathogenic role. Anti-TNF therapy has shown to decrease skin and serum metalloproteinases levels in psoriasis. We report a 61-year-old man with peripheral corneal melting syndrome associated with psoriatic arthritis who received Adalimumab to control skin and ocular inflammation. To our knowledge, this is the first case report of peripheral corneal melting syndrome in psoriatic arthritis treated with Adalimumab showing resolution of skin lesions and complete healing of corneal perforation in three months.

Cyanoacrylate tissue glue for wound repair in early posttrabeculectomy conjunctival bleb leak: a case series

We demonstrated a noninvasive management of early bleb leak following trabeculectomy using cyanoacrylate tissue glue (CATG). Three patients who underwent augmented trabeculectomy with mitomycin C with early bleb leak between January 2009 and June 2010 were reviewed. Case 1 and Case 2 exhibited bleb leak on postoperative Day 1 and Case 3 showed leak on follow-up at postoperative Day 7. Case 1 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and bandage contact lens. Case 2 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and conjunctiva flap resuturing. In Case 3, the leaking conjunctival flap was managed with combined techniques of resuturing and applying CATG at postoperative Day 9, after failed pressure padding. During leakage, the intraocular pressure was low (6–8 mmHg) in all three cases, with shallow anterior chamber depth and absence of other complications such as choroidal detachment, hypotony maculopathy, or endophthalmitis. Foreign body sensation was the main complaint following the procedure. No clinical allergy reaction was documented. CATG may serve as a potential adjunctive and effective method in the management of posttrabeculectomy early bleb leak.

Hypersensitivity to sub-Tenon's topotecan in fibrin adhesive in patients with retinoblastoma

Sub-Tenon's space delivery of topotecan in a fibrin sealant was used as an adjunct to laser therapy for small retinoblastoma tumors in 25 children (77 injections). We report serious hypersensitivity reactions in 2 children on their third sub-Tenon's injection of topotecan in fibrin sealant. One child subsequently had topotecan in an autologous blood clot with no allergic reaction. Although allergic reaction to topotecan has been reported in the literature, fibrin glue reactions are more common and are likely due to aprotinin hypersensitivity.

Assessment of Closure Competency of Sutureless Vitrectomy Sclerotomies After Scleral Hydration

PURPOSE

To assess the influence that hydration applied on the sclerotomy edges may have on incisional closure resistance after transconjunctival sutureless vitrectomy (TSV).

METHODS

Experimental, randomized and observer-masked study in which 23-gauge TSV was performed in 80 cadaveric pig eyes. Once each vitrectomy was finished, hydration with balanced salt solution (BSS) was applied on the sclerotomy edges of one of the superior incision sites; no maneuver was performed on the other superior sclerotomy. Intraocular pressure (IOP) was gradually increased by means of the vitrectomy system (Accurus; Alcon Laboratories, TX) until one of the superior sclerotomies opened, allowing internal ocular solution to escape.

RESULTS

In 45% of cases (36 of 80 eyes), sclerotomies subjected to hydration allowed intraocular fluid escape (p = 0.43). There were no differences when comparing opening pressure values of hydrated and non-hydrated sclerotomies (p = 0.19).

CONCLUSIONS

Scleral hydration did not demonstrate increase in the sclerotomy closure resistance in our experimental model. Given the widespread use of sutureless TSV around the world, the results obtained in our research, in spite of being negative, may contribute to the knowledge of the behavior of sutureless sclerotomies.

Fixation of Extraocular Muscles to Porous Orbital Implants Using 2-Ocetyl-Cyanoacrylate Glue

PURPOSE

To assess the efficacy of recti muscle fixation with 2-ocetyl-cyanoacrylate tissue glue to porous orbital implants in human subjects undergoing enucleation.

METHODS

This was a prospective interventional study with a historical control group. Over a 1-year period, patients who received orbital implant fixation using 2-ocetyl-cyanoacrylate tissue glue were enrolled in the study. Functional assessment was carried out by measurement of implant motility at the 6-month postoperative period, which was compared with a historical control group of patients with sutured implants. Structural assessment was carried out with a random sample of orbital MRIs.

RESULTS

Twelve patients received the glue-fixation technique. There were no intraoperative or immediate postoperative complications. There was no statistically significant difference between the glued and sutured groups' horizontal implant movement (7.0 mm ± 1.5 mm vs. 6.8 mm ± 1.8 mm, respectively; p = 0.85) or vertical implant movement (5.6 mm ± 1.7 mm vs. 5.0 mm ± 1.4 mm, respectively; p = 0.39). Sample orbital MRI demonstrated good muscle approximation to the implants as well as contrast enhancement suggestive of successful fibrovascular proliferation.

CONCLUSIONS

Recti muscle fixation using 2-ocetyl-cyanoacrylate tissue glue to porous orbital implants appeared safe and produced good functional and structural results in this proof-of-concept study. This novel technique of implant fixation may offer benefits in terms of reduced operating room time and cost savings.

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.

Future perspectives for regenerative medicine in ophthalmology

Repair and reconstruction of the cornea has historically relied on synthetic materials or tissue transplantation. However, the future holds promise for treatments using smart biomaterials and stem cells that direct tissue repair and regeneration to ultimately create new ocular structures that are indistinguishable from the original native tissue. The cornea is a remarkable engineering structure. By understanding the physical structure of the tissue and the resulting impact of the structure on biological function, we can design novel materials for a number of ophthalmic clinical applications. Furthermore, by extending this structure-function approach to characterizing corneal disease processes, new therapies can be engineered.

Preparation, indications and results of human amniotic membrane transplantation for ocular surface disorders

In comparison with other biologic tissues used as reconstructive grafts, the amniotic membrane has the advantage that it is thinner and better tolerated by the patient. Amniotic membrane, when appropriately preserved, can be used as a substrate replacement, such that host cells can migrate into the membrane to form new and healthy tissue. The amniotic membrane is the deeper layer of the fetal membrane; it is avascular, multilayered tissue with antiangiogenic, antiscarring and anti-inflammatory properties. Since it does not express antigens of histocompatibility, the membrane is never rejected by the receiving tissues. In addition, the beneficial effects of reducing inflammation and neovascularization persist for a long time, if properly cryopreserved.

Our experience of fibrin sealant-assisted implantation of Ahmed glaucoma valve

Aim:

To report our experience with the fibrin sealant as a suture substitute for securing the human scleral patch graft during implantation of Ahmed glaucoma valve (AGV).

Materials and Methods:

A retrospective, non-comparative study of 12 eyes of 12 patients who underwent an AGV implantation with fibrin sealant for part of the procedure during June 2009 to September 2010.

Results:

The mean patient age was 21.5 ± 20.6 years. Male: Female ratio was 2 : 1. Seven (58.3%) patients were monocular. The indications for AGV were varied. The mean number of intra-ocular surgeries prior to an implantation of AGV was 1.8. The mean follow-up duration was 24.5 ± 17.9 weeks. There was a statistically significant reduction in the mean IOP and in the mean number of anti-glaucoma medications at the final visit compared to the pre-operative values (P < 0.01, paired t test). Conjunctival retraction was seen in 1 (8.3%) case. The scleral patch graft was retracted posteriorly in another (8.3%) case. There was no case of AGV tube exposure, tube-cornea touch, or conjunctival erosion. Vision threatening complication viz. late post-operative rhegmatogenous retinal detachment, unlikely to be related to the use of the fibrin sealant, occurred in 2 (16.6%) eyes.

Conclusion:

The fibrin sealant offers the advantages of safety and convenience to the placement of a scleral patch graft during an AGV implantation.

Diathermy of leaking sclerotomies after 23-gauge transconjunctival pars plana vitrectomy: a prospective study

PURPOSE

To evaluate the efficacy of bipolar diathermy in ensuring closure of leaking sclerotomies after complete 23-gauge transconjunctival sutureless vitrectomy.

METHODS

In this prospective, interventional case series, in 136 eyes of 136 patients with at least one leaking sclerotomy at the end of a complete 23-gauge transconjunctival sutureless vitrectomy, external bipolar wet-field diathermy was applied to leaking sclerotomies, including the conjunctiva and sclera. Intraoperative wound closure, and postoperatively, at 6 hours, 1 day and 3 days, sclerotomies leakage, intraocular pressure, hypotony, and hypotony-related complications were evaluated.

RESULTS

Intraoperative closure was achieved in 231 of 238 leaking sclerotomies (97%) that received diathermy. One of these with postoperative leakage needed suture. Compared with baseline (14.4 ± 2.8 mmHg), mean intraocular pressure was lower at 6 hours (13.2 ± 3.8 mmHg, Tukey-Kramer P < 0.001) and not different at 24 hours or 72 hours. Hypotony (intraocular pressure <5 mmHg) was observed in 6 eyes (4.5%) at 6 hours, in 2 (1.5%) at 24 hours, and in none at 3 days. Logistic regression analysis showed that, 6 hours postoperatively, hypotony was related to younger age (≤50 years) at surgery (P = 0.031). No hypotony-related complications were recorded.

CONCLUSION

Bipolar wet-field diathermy of sutureless sclerotomies is an effective method for ensuring a leaking sclerotomies closure.

A comparison between fibrin sealant and sutures for attaching conjunctival autograft after pterygium excision

BACKGROUND

Use of conjunctival autograft following excision of primary pterygium has reduced the recurrence rate. This study evaluates the efficiency of fibrin glue as compared to sutures in attaching the conjunctival autograft with reference to surgical time, post operative comfort and recurrence during follow up.

METHODS

60 patients with primary pterygium were included and divided into two groups. In the first group autograft was secured in place with help of 10-0 polyamide monofilament suture while in second group fibrin glue was used. Both the groups were compared in terms of operative time, post op comfort and recurrence.

RESULTS

The average surgical time taken was 50.93 ± 4.96 min with suture group and 34.43 ± 4.94 min with fibrin glue group. Pain and foreign body sensation was markedly less with fibrin glue group. At the end of final follow up at 6 months, 3 cases (10%) from suture group and 1 case (3.33%) from fibrin group had recurrence.

CONCLUSION

Fibrin glue is effective and safe for attaching conjunctival autograft during pterygium surgery. Although more number of recurrences were observed in suture group as compared to fibrin glue group the difference was not statistically significant (p 0.612).

Management of pediatric corneal limbal dermoids

This paper reviews the data in the published literature (PubMed from 1937 to 2011) concerning the medical and surgical management of pediatric limbal dermoids. Current standard medical treatment for grade I pediatric limbal dermoids (ie, with superficial corneal involvment) is initially conservative. In stages II (ie, affecting the full thickness of the cornea with/without endothelial involvement) and III (ie, involvement of entire cornea and anterior chamber), a combination of excision, lamellar keratoplasty, and amniotic membrane and limbal stem cell tranplantation are advocated. Combinations of these approaches seem to yield better and more stable long-term ocular surface cosmesis and fewer complications in comparison with traditional methods of excision and lamellar keratoplasty. Management of amblyopia (i.e. occlusion treatment, chemical penalization with/without spectacle wear, etc) must continue after surgical excision to yield optimal results when or if the surgery is done at a younger age.

Experimental application of tissue adhesives in corneal traumas

OBJECTIVE

To evaluate intraoperative difficulties of the use of glues for corneal trauma.


METHODS

Partial or full-thickness perpendicular corneal incisions (3-4 mm straight cuts) near the limbus (perpendicular or parallel to it) were made in 8 albino rabbits and were then sealed with fibrin or cyanoacrylate glue. Follow-up examinations were performed under the surgical microscope. Tissue specimens were also taken for light microscopic evaluation. 


RESULTS

The cyanoacrylate glue polymerized almost immediately after application on the tissue, limiting the ability of the surgeon to oppose the corneal incisions appropriately. The fibrin glue polymerized more gradually, giving enough time for manipulations to reconstruct the wound properly and for removal of excessive glue, especially when the 2 components were applied separately. Excessive glue and crust formation on the eye surface induced irritation.


CONCLUSIONS

Fibrin glue for the reconstruction of corneal wounds was easier to use than cyanoacrylate glue and caused less glue crust formation on the corneal surface. The speed of polymerization is an important factor. Excessive glue on the cornea was irritating.

A comparative study of the effect of fibrin glue versus sutures on clinical outcome in patients undergoing pterygium excision and conjunctival autografts

Purpose

To compare the effect of using fibrin glue or 10-0 nylon sutures on the clinical outcome of patients undergoing pterygium excision and conjunctival autografting.

Methods

We retrospectively reviewed the medical records of 52 eyes from 46 patients who underwent pterygium excision and conjunctival autografting and were followed up for more than 3 months. The operation duration, postoperative inflammation, complications, and recurrence rates were compared between groups of 20 patients (22 eyes) for whom fibrin glue was used (fibrin glue group) and 26 patients (30 eyes) for whom suturing was performed with 10-0 nylon (suture group) in pterygium excision and conjunctival autografting.

Results

The operation duration was 27.71 (5.22) minutes in the fibrin glue group and 43.30 (8.18) minutes in the suture group (p = 0.000). Seven days after the operation, the fibrin glue group showed milder conjunctival inflammation than the suture group (p = 0.000). Postoperative complications and corneal recurrence rates were not statistically different between the two groups.

Conclusions

The use of fibrin glue in pterygium excision with conjunctival autografting is likely to be a more effective, safer procedure than suturing.

Influence of sealant fibrin on the wound healing of the pigs vocal folds

Fibrin sealants or fibrin glue are products made from human plasma proteins, which mimic the final pathway of the coagulation cascade. Its application to stimulate the healing process has been a topic of debate in the literature. The use of fibrin sealants in phonosurgery has been empirical; there have been no studies that investigate the action of fibrin sealant in Reinke's space.

Aim

To evaluate the effect of fibrin glue in healing of the vocal folds of pigs after surgical manipulation.

Materials and Methods

This was a prospective and experimental study. Six animals had both vocal folds incised. Sealant was applied in one of them; the other served as a control. After three months, the animals were sacrificed and a collagen count was carried out.

Results

The side on which glue was applied had an average of 27.8% against 20.4% of the side without glue.

Conclusion

The collagen concentration in the samples where the fibrin sealant was applied was significantly higher compared to samples without glue. Thus, the presence of a fibrin sealant stimulates fibrogenesis in this tissue.

Paste-pinch-cut conjunctivoplasty: subconjunctival fibrin sealant injection in the repair of conjunctivochalasis

PURPOSE

To describe a new surgical technique for the repair of conjunctivochalasis (CCh) using subconjunctival injection of fibrin sealant followed by conjunctival resection and to present a case series demonstrating our experience with the paste-pinch-cut technique.

METHODS

A total of 139 eyes of 70 patients (43 women, 27 men) with CCh unresponsive to medical therapy received the described surgical treatment. The procedure consists of 3 primary steps-paste: fibrin sealant is injected subconjunctivally in a line inferior to the limbus; pinch: the conjunctiva is grasped with curved ptosis forceps, gathering the excess conjunctiva into a ridge, which is held, allowing the sealant to polymerize; and cut: the ridge of excess conjunctiva and sealant is resected. Subjective symptoms were assessed after surgery.

RESULTS

Conjunctival redundancy was absent postoperatively in all eyes, resulting in a smooth conjunctival surface and restored tear meniscus. At the 3-month follow-up visit, 91.4% of patients reported improvement in symptoms. There were no recurrences or significant complications.

CONCLUSIONS

The present retrospective, noncomparative, consecutive, interventional case series study introduces paste-pinch-cut conjunctivoplasty as a simple and an effective surgical treatment for the repair of CCh in symptomatic patients.

Preoperative factors influencing success in pterygium surgery

Background

To identify preoperative, perioperative and postoperative risk factors that influence the success of pterygium surgery.

Methods

This is a prospective study of thirty-six patients with primary or recurrent pterygia. A detailed anamnesis and an ophthalmological examination were performed looking for the following factors: age, race, latitude and altitude of the main place of residence, hours of exposure to the sun, use of protective measures against UV-radiation, classification of pterygium, width of the pterygium at limbus, surgical technique (conjunctival autograft plus suturing versus tissue glue), graft alterations (misapposition, granuloma, haemorrhage, oedema, retraction or necrosis), and postoperative symptoms (foreign-body sensation, pain). The examinations were performed 2 and 7 days and 2, 6 and 12 months after surgery. In addition, recurrence was defined as any growth of conjunctiva into the cornea.

Results

A logistic regression and a survival analysis have been used to perform data analysis. A total number of 36 patients completed a one year follow-up. A total of 13 patients were born and lived in Spain, and 26 came from other countries, mostly Latin America. A total number of 8 males (no women) presented a recurrence, mainly between 2 and 6 months. The hours of sun exposure through their life was independently related to surgical success. Pterygia of less than 5 mm of base width showed a weak positive correlation with recurrence. None of the other factors considered were significantly related to recurrence.

Conclusions

Male gender and high sun exposure are strongly and independently related to surgical success after the removal of pterygia.

Optimization of Fibrin Glue Spray Systems for Ophthalmic Surgery

PURPOSE

To optimize fibrin glue (FG) spray for ophthalmic surgery using two spray applicators, EasySpray and DuploSpray systems, by varying the distance from point of application and the pressure/flow rate, and to compare the adhesive strength of sutured and sutureless (FG sprayed) conjunctival graft surgery in a rabbit model.

METHODS

FG was sprayed on a 0.2 mm-thick sheet of paper using EasySpray by variously combining application distances of 2.5, 5, 7.5, and 10 cm with pressures of 10, 15, and 20 psi. DuploSpray was used at the same distances but with varying flow rates of 1 and 2 L/min. Subsequently, FG was sprayed on porcine corneas and FG thickness was analyzed by histology. In addition, adhesive strength of the conjunctival graft (0.5 × 0.5 cm) attached to the rabbit cornea by sutured and sutureless surgery (FG spray) was compared using a tension meter.

RESULTS

Histology measurements revealed that the FG thickness decreased with increases in distance and pressure of spray using the EasySpray applicator on paper and porcine corneal sections. The adhesive strength of the sutured conjunctival graft (41 ± 4.85 [kilopascal] KPa) was found to be higher than the graft attached by spraying (10 ± 2.3 KPa) and the sequential addition of FG (6 ± 0.714 KPa).

CONCLUSIONS

The EasySpray applicator formed a uniform spread of FG at a distance-pressure combination of 5 cm and 20 psi. The conjunctival graft attached with sutures had higher adhesive strength compared with grafts glued with a spray applicator. Although the adhesive strength of FG applied through the applicator was similar to the drop-wise sequential technique, the former was more cost effective because more samples could be sprayed compared with the sequential manual technique.

TRANSLATIONAL RELEVANCE

The standardization of the spray system for the application of FG in ophthalmology will provide an economical method for delivering consistent healing results after surgery.

Comparison of bursting pressure after scleral tunnel incision sealed with sutures or an adherent ocular bandage in human globes

OBJECTIVE

To evaluate the efficiency of a hydrogel adherent ocular bandage for sealing of scleral tunnel incisions in human eye globes.

METHODS

A 4-mm scleral tunnel incision was made in each of 10 globes and bursting pressure was measured using the Seidel test to check for wound leakage. Globes were sealed using either two interrupted 10-0 nylon sutures (n = 5) or an adherent ocular bandage in the form of polyethylene glycol hydrogel (n = 5). Bursting pressure was then measured for a second time.

RESULTS

Bursting pressure was significantly higher after wound sealing in both groups. There were no statistically significant differences in bursting pressure between the two groups before or after sealing.

CONCLUSIONS

The adherent ocular bandage successfully protected the incision in ex vivo human globes immediately after surgery, with a sealing efficiency comparable to two nylon sutures, suggesting that it is a safe and effective alternative to conventional suturing.

Evaluation of tensile strength of tissue adhesives and sutures for clear corneal incisions using porcine and bovine eyes, with a novel standardized testing platform

BACKGROUND

Tissue adhesives for ophthalmologic applications were proposed almost 50 years ago, yet to date no adequate tissue glues have been identified that combine strong sealing properties with adequate safety and absence of postsurgical side effects. In recent years, cataract surgeries and Descemet's stripping with endothelial keratoplasty procedures have significantly increased the number of clear corneal incisions performed. One of the obstacles to discovery and development of novel tissue adhesives has been the result of nonstandardized testing of potential tissue glues.

METHODS

We developed an instrument capable of controlling intraocular pressure in explanted porcine and bovine eyes in order to evaluate sealants, adhesives, and surgical closure methods used in ophthalmic surgery in a controlled, repeatable, and validated fashion. We herein developed and validated our instrument by testing the adhesive properties of cyanoacrylate glue in both porcine and bovine explant eyes.

RESULTS

The instrument applied and maintained intraocular pressure through a broad range of physiological intraocular pressures. Cyanoacrylate-based glues showed significantly enhanced sealing properties of clear corneal incisions compared with sutured wounds.

CONCLUSION

This study shows the feasibility of our instrument for reliable and standardized testing of tissue adhesive for ophthalmological surgery.

Sutureless sealing of penetrating corneal wounds using a laser-activated thin film adhesive

BACKGROUND AND OBJECTIVES

To demonstrate the feasibility of a novel, thin film, laser-activated adhesive in sealing penetrative corneal wounds with a view to replacing sutures in ophthalmic operations.

METHODS

A previously described thin film adhesive composed of chitosan and indocyanine green activated by infrared laser (808 nm) was used to seal penetrating corneal wounds ranging from 1 to 6 mm in size in enucleated bovine eyes. The excised corneas were subjected to pressure tests to evaluate the strength of the corneal repairs and compared to sutures and commercial fibrin glue, Tisseel®. Temperatures at the adhesive-tissue interface were measured and histological examinations of the repairs performed to investigate potential tissue damage. Biodegradability of the films was monitored in lysozyme solutions at concentrations reported in tears.

RESULTS

The adhesive effectively sealed corneal wounds, withstanding pressures of 140-320 mmHg, far in excess of the normal intraocular pressure. In contrast, pressures of 40-80 mm Hg were determined using a combination of sutures with Tisseel® as a sealant. The laser-activation process was 1.5-5 times faster than other procedures studied and required no curing time. A transient, mean temperature of 56 ± 2°C was measured at the adhesive-tissue interface while histology showed no tissue damage as a consequence of the irradiation process. Irradiation had no significant influence on adhesive biodegradation in vitro, which lost approximately 30% of their initial weight in a lysozyme solution (6 mg ml(-1)).

CONCLUSIONS

The thin film adhesive was found to be an effective in sealing corneal wounds with considerable advantages over sutures, including speed of application and sealing strength and biodegradability.

Surgical management of pediatric limbal dermoids with sutureless amniotic membrane transplantation and augmentation

PURPOSE

To further evaluate the efficacy of a new surgical technique for removal of pediatric corneal-limbal dermoids and ocular surface reconstruction using multilayered amniotic membrane.

METHODS

Three pediatric patients with corneal-limbal dermoid (grade I) in one practice were identified in a retrospective fashion. All patients underwent deep lamellar excision followed by sutureless multilayered amniotic membrane transplantation by a single surgeon (AP). Preoperative and postoperative visual acuity, anterior segment examination, anterior segment B-scan, and cycloplegic refraction were performed.

RESULTS

Three patients with ages ranging from 6 months to 18 years had a postoperative follow-up of 9 to 12 months from the time of surgery. This surgical technique achieved rapid postoperative corneal re-epithelialization, reduced postoperative pain, and diminished postoperative scarring in all three patients. Existing preoperative astigmatism remained unchanged throughout the follow-up period. No intraoperative or postoperative complications were noted.

CONCLUSION

This surgical approach offers an alternative surgical technique to a simple excision with or without deep lamellar keratoplasty for removal of pediatric corneal-limbal dermoids (grade I). In the management of pediatric limbal dermoids (grade I), surgical excision combined with sutureless multilayered amniotic membrane transplantation eliminates painful postoperative recovery and corneal neovascularization, and can achieve an improved long-term ocular surface cosmesis.

Sealing effects of cross-linked gelatin

Surgical sealants form gel when applied to tissues. Currently, fibrin sealant has been successfully used in many surgical fields, but it has several disadvantages, including possible virus transmission, low adhesive strength, and high cost. In this study, gelatin and glutaraldehyde (GA) solutions were chosen to demonstrate the effectiveness of cross-linked gelatin gel as sealant and barrier, both of which have long been used in medical applications. It was found that the gelatin gel prepared from 26 wt% gelatin and 1 wt% GA solutions exhibited bonding strength almost three times higher than that of fibrin glue. The bonding strength increased with the increasing gelatin and GA concentrations. When a needle hole on PTFE vascular grafts was sealed with the gelatin gel, the water-resistant pressure significantly increased upon rubbing and was twice higher than that of fibrin glue. The cytotoxicity of gelatin gel was found to be much lower than that of albumin glue prepared at the same composition as commercially available BioGlue®. The gelatin gel was found to be also effective as barrier to prevent adhesion in a rat cecum abrasion model.

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.

Comparison of fibrin glue and sutures for conjunctival wound closure in strabismus surgery

Purpose

To evaluate and compare the efficacy and tolerance of fibrin glue and sutures for closing conjunctival wounds in strabismus surgery.

Methods

In a prospective trial, we performed strabismus surgery using limbal incisions. Conjunctival wounds were closed with fibrin glue in 20 eyes of 20 patients (fibrin group) and 8-0 polyglactin suture in 20 eyes of 20 patients (suture group). Postoperative pain, tearing, and inflammation were compared at 1 day, 1 week, 3 weeks, and 6 weeks after surgery. Conjunctival incision healing was also investigated.

Results

One day and one week post-operatively, pain and tearing scores were lower in the fibrin group (p = 0.000, respectively). Mean surgery time was significantly shorter in the fibrin (48 ± 5 minutes) than the suture group (63 ± 7 minutes) (p = 0.000). Inflammation was significantly more severe in the suture group until 3 weeks postoperative (p = 0.000, respectively), but conjunctival healing did not differ between the groups. Hyperemia appeared more prominent in the fibrin group 3 and 6 weeks after surgery (p = 0.087 and 0.000, respectively). Two eyes in the fibrin group showed conjunctival gaps of more than 2 mm, which closed spontaneously by three weeks after surgery. No allergic reactions or infections developed.

Conclusions

Fibrin glue proved to be as effective as sutures in closing conjunctival wounds. It provides more comfortable early postoperative courses and might be considered as an alternative to sutures in strabismus surgery.

Effects of coagulase-negative staphylococci and fibrin on breast capsule formation in a rabbit model

BACKGROUND

The etiology and ideal clinical treatment of capsular contracture (CC) remain unresolved. Bacteria, especially coagulase-negative staphylococci, have been previously shown to accelerate the onset of CC. The role of fibrin in capsule formation has also been controversial.

OBJECTIVE

The authors investigate whether fibrin and coagulase-negative staphylococci (CoNS) modulate the histological, microbiological, and clinical outcomes of breast implant capsule formation in a rabbit model and evaluate contamination during the surgical procedure.

METHODS

Thirty-one New Zealand white female rabbits were each implanted with one tissue expander and two breast implants. The rabbits received (1) untreated implants and expanders (control; n = 10), (2) two implants sprayed with 2 mL of fibrin and one expander sprayed with 0.5 mL of fibrin (fibrin; n = 11), or (3) two implants inoculated with 100 µL of a CoNS suspension (10(8)CFU/mL-0.5 density on the McFarland scale) and one expander inoculated with a CoNS suspension of 2.5 × 10(7) CFU/mL (CoNS; n = 10). Pressure/volume curves and histological and microbiological evaluations were performed. Operating room air samples and contact skin samples were collected for microbiological evaluation. The rabbits were euthanized at four weeks.

RESULTS

In the fibrin group, significantly decreased intracapsular pressures, thinner capsules, loose/dense (<25%) connective tissue, and negative/mild angiogenesis were observed. In the CoNS group, increased capsular thicknesses and polymorph-type inflammatory cells were the most common findings. Similar bacteria in capsules, implants, and skin were cultured from all the study groups. One Baker grade IV contracture was observed in an implant infected with Micrococcus spp.

CONCLUSIONS

Fibrin was associated with reduced capsule formation in this preclinical animal model, which makes fibrin an attractive potential therapeutic agent in women undergoing breast augmentation procedures. Clinical strategies for preventing bacterial contamination during surgery are crucial, as low pathogenic agents may promote CC.

Recurrence rate using fibrin glue-assisted ipsilateral conjunctival autograft in pterygium surgery: 2-year follow-up

AIMS

To determine the recurrence rate after pterygium excision with ipsilateral conjunctival autograft using fibrin glue.

METHODS

One hundred eleven eyes of 92 patients operated for primary pterygium were retrospectively evaluated for recurrence rate and intraoperative and postoperative complications. Pterygia were preoperatively divided in atrophic/grade 1 (n = 2; 1.80%), intermediate/grade 2 (n = 85; 76.58%), or fleshy/grade 3 (n = 24; 21.62%) types. All patients were operated using an ipsilateral conjunctival autograft fixed with fibrin glue. Only patients with 2-year follow-up were included in this study.

RESULTS

Two years after surgery, the mean recurrence rate was 4.50% (n = 5). No intraoperative complications were noted. Postsurgical complications were graft pseudoedema (n = 45; 40.54%), graft retraction (n = 3; 2.70%), and donor site granuloma (n = 1; 0.90%).

CONCLUSION

Fibrin glue-assisted ipsilateral conjunctival autograft seems to be safe and efficacious and associated with a low rate of recurrence.