Evicel versus Tisseel versus Sutures for Attaching Conjunctival Autograft in Pterygium Surgery

The Efficacy of Fibrin Sealant in Sutureless Deep Sclerectomy-Preliminary Outcomes

PRCIS

Deep sclerectomy (DS) with fibrin adhesive can constitute a safe alternative to the classic procedure using sutures, providing nonallergenic, nontoxic, and secure adhesion with no sign of aqueous humor outflow obstruction postoperatively.

OBJECTIVE

To evaluate short and medium-term postoperative results of DS with a fibrin sealant.

PATIENTS AND METHODS

This prospective, noncomparative, interventional case series involves 12 eyes of 12 patients with uncontrolled open angle glaucoma who underwent DS with Esnoper (Clip or V2000) implant between February 2021 and March 2022. A novel method of wound closure (sclera, Tenon fascia, and conjunctiva) employing fibrin glue was used instead of classic sutures. Surgical outcomes assessed include: intraocular pressure and glaucoma therapy reduction, best-corrected visual acuity changes, and number of complications registered peri and postoperatively. All measurements were performed preoperatively, as well as at 1 day, at 1 and 2 weeks, and at 1, 2, 3, 6, 9, and 12 months after surgery.

RESULTS

The mean intraocular pressure decreased from 24.0 ± 9.1 mm Hg to 13.8 ± 6.3 mm Hg at 1 year postoperatively ( P < 0.001). Kaplan-Meier survival analysis revealed complete and qualified success rates of 83.3% and 91.7%. The mean glaucoma therapy decreased from 3.2 ± 1.1 to 0.8 ± 1.3 drugs 12 months after surgery ( P < 0.001). Nd:YAG goniopunture was performed in 2 eyes at 1 and 12 months postoperatively. No significant best-corrected visual acuity changes were registered. Perioperatively, we noted a trabeculo-descemet microperforation in 1 eye, transient hypotony in 5 eyes, and mild hyphema in 2 eyes.

CONCLUSIONS

Fibrin adhesive provided an effective closure in sutureless DS in the patients included in our study. This modification of classical DS may simplify the surgical technique, ensure secure wound adaptation, optimize healing, and lower the risk of inflammation and fibrosis postoperatively.

Key Genes of Immunity Associated with Pterygium and Primary Sjögren's Syndrome

Pterygium and primary Sjögren's Syndrome (pSS) share many similarities in clinical symptoms and ocular pathophysiological changes, but their etiology is unclear. To identify the potential genes and pathways related to immunity, two published datasets, GSE2513 containing pterygium information and GSE176510 containing pSS information, were selected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) of pterygium or pSS patients compared with healthy control conjunctiva, and the common DEGs between them were analyzed. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted for common DEGs. The protein-protein interaction (PPI) network was constructed using the STRING database to find the hub genes, which were verified in clinical samples. There were 14 co-upregulated DEGs. The GO and KEGG analyses showed that these common DEGs were enriched in pathways correlated with virus infection, antigen processing and presentation, nuclear factor-kappa B (NF-κB) and Th17 cell differentiation. The hub genes (IL1R1, ICAM1, IRAK1, S100A9, and S100A8) were selected by PPI construction. In the era of the COVID-19 epidemic, the relationship between virus infection, vaccination, and the incidence of pSS and pterygium growth deserves more attention.

Autologous fibrin glue versus sutures for conjunctival autograft in primary pterygium: a randomized clinical trial

PURPOSE

To describe and compare the autologous fibrin glue and traditional sutures for conjunctival graft attachment in patients undergoing primary pterygium excision surgery.

METHOD

A randomized clinical trial included patients who underwent pterygium surgery with conjunctival autologous graft (CAG). Using randomization, a single-trained surgeon performed graft fixation with autologous glue or sutures. The glue was prepared immediately before the surgery, using the patient's blood components. After centrifugation, the plasma was collected and enhanced with calcium gluconate. Postoperative assessments were performed on Days 1, 7, 21, 30 and 180. The study evaluated postoperative edema and pain and complications. The mean surgical time was compared. Recurrence of the pterygium was assessed 6 months postoperatively.

RESULTS

The study evaluated 61 eyes. Thirty-three eyes underwent pterygium surgery using the glue technique, and 28 underwent the traditional suture technique. Fifty-one patients (83.60%) had successful graft adhered to at the end of follow-up. Ten patients (10/33) lost their graft in the glue group, and only 69.70% maintained graft presence in the fourth week versus 100% of the patients in the suture group (p = 0.001). Pain scores were lower in the glue group, and clinical edema was significantly higher. There was no significant difference in graft retraction or the presence of granuloma, necrosis or postoperative infection.

CONCLUSION

Autologous fibrin glue is an affordable option for CAG fixation in particular contexts where commercial fibrin glue is unavailable, and it could offer advantages compared to sutures. A higher graft loss rate was observed and might be related to topical anesthesia, and improvements to the technique are needed.

CLINICALTRIALS

gov Identifier: NCT04151017. https://clinicaltrials.gov/ct2/show/NCT04151017?term=20170467&draw=1&rank=1 .

Composition, host responses and clinical applications of bioadhesives

Bioadhesives are medical devices used to join or seal tissues that have been injured or incised. They have been classified into tissue adhesives, sealants, and hemostatic agents. Bioadhesives such as FloSeal®, CoSeal®, BioGlue®, Evicel®, Tisseel®, Progel™ PALS, and TissuGlu® have been commercialized and used in clinical setting. They can be formulated with natural or synthetic components or a combination of both including albumin, glutaraldehyde, chitosan, cyanoacrylate, fibrin and thrombin, gelatin, polyethylene glycol (PEG), along with urethanes. Each formulation has intrinsic properties and has been developed and validated for a specific application. This review article briefs the mechanisms by which bioadhesives forms adhesion to tissues and highlights the correlation between bioadhesives composition and their potential host responses. Furthermore, clinical applications of bioadhesives and their application-driven requirements are outlined.

Repeated use of fibrin sealants kept at room temperature in conjunctival autografting: An animal study

Purpose:

In this study, our aim was to investigate if fibrin adhesives used in conjunctival wound surgery with autologous conjunctival grafts could be used repeatedly at different times after surgical opening.

Methods:

40 New Zealand rabbits were used in the study. These animals were divided into four groups, each consisting of 10 rabbits, and hence 20 eyes. In the first group (control group), Tisseel fibrin sealant was used on the day the eye was first opened surgically; in the second group, it was used on the seventh day; on the third group, it was used on the 14^th day; and in the fourth group, it was used 28 days after surgical opening. The graft from the inferior bulbar conjunctiva was attached using Tisseel fibrin glue to the superior scleral bed at the location where the superior bulbar conjunctiva was excised in the same eye.

Results:

No microbial growth was detected in the cultures of the samples tested. There were two partial graft loss in group 2 and there was one partial graft loss in each group of the other groups, and further total graft loss was present in one rabbit in group 3. None of the rabbits had any complications like granuloma, Corneal dellen or infection.

Conclusion:

Based on these results, fibrin sealants can be used repeatedly by storing them at room temperature. Repeated use of fibrin adhesives will reduce the cost of ophthalmologic surgeries and non-ophthalmologic surgeries.

Surgical Techniques and Adjuvants for the Management of Pterygium

OBJECTIVE

To provide an updated review of surgical techniques and adjuvants for the management of pterygium.

METHODS

A literature search was conducted in PubMed for studies published since January 2011. "Pterygium surgery" and the MeSH term "Pterygium/surgery" was used. The results were filtered for randomized controlled trials in English, yielding 60 citations.

RESULTS

One study compared topical anesthetic agents. One study compared methods of corneal polishing of the corneoscleral bed after pterygium excision. Numerous studies evaluated the use of conjunctival autograft versus amniotic membrane, superior versus inferior conjunctival autograft, and conjunctival versus limbal-conjunctival autograft. Many studies evaluated graft fixation methods. Several studies evaluated the adjuvant use of mitomycin C, 5-fluorouracil, and bevacizumab. A few studies evaluated the adjuvant use of steroids. Eleven studies evaluated various methods of postoperative management.

CONCLUSIONS

Current evidence supports pterygium excision with conjunctival autograft fixation using fibrin glue, followed by patching until the first postoperative visit. Surgical adjuvants and postoperative use of artificial tears and topical cyclosporine 0.05% may further reduce recurrence. Postoperative use of topical steroids is highly variable because there is no consensus regarding the optimal dose, frequency, and duration of treatment.

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.

Surgical applications of intracorporal tissue adhesive agents: current evidence and future development

Introduction: Traditional mechanical closure techniques pose many challenges including the risk of infection, tissue reaction, and injury to both patients and clinicians. There is an urgent need to develop tissue adhesive agents to reform closure technique. This review examined a variety of tissue adhesive agents available in the market in an attempt to gain a better understanding of intracorporal tissue adhesive agents as medical devices.Areas covered: Fundamental principles and clinical determinants of the tissue adhesives were summarized. The available tissue adhesives for intracorporal use and their relevant clinical evidence were then presented. Lastly, the perspective of future development for intracorporal tissue adhesive were discussed. Clinical evidence shows current agents are efficacious as adjunctive measures to mechanical closure and these agents have been trialed outside of clinical indications with varied results.Expert opinion: Despite some advancements in the development of tissue adhesives, there is still a demand to develop novel technologies in order to address unmet clinical needs, including low tensile strength in wet conditions, non-controllable polimerization and sub-optimal biocompatibility. Research trends focus on producing novel adhesive agents to remit these challenges. Examples include the development of biomimetic adhesives, externally activated adhesives, and multiple crosslinking strategies. Economic feasibility and biosafety are limiting factors for clinical implementation.

Femtosecond Laser-assisted Preparation of Conjunctival Autograft for Pterygium Surgery

Femtosecond laser-assisted conjunctival autografts (CAG) preparation was recently proposed. This study reports the outcomes of the first clinical trial on the use of laser to prepare CAG in pterygium surgery, and to compare the outcomes with those of manual technique. Forty eyes undergoing primary pterygium excision with laser-assisted CAG transplantation were prospectively included (L group). Two historical matched cohorts whose CAGs were prepared manually were compared (n = 78 eyes by the same experienced surgeon, M group; n = 78 eyes by trainees; TM group). We found the laser-created CAGs had only 11 μm deviation from the targeted thickness. The best-corrected visual acuity improved, and the astigmatism significantly decreased after surgery, with comparable efficacy across 3 groups. The 1-year recurrence rate was 2.5%, 3.8% and 7.7% in the L, M and TM groups, respectively (P = 0.12). There was no significant difference between the L and M groups in the complication rate (5.0% and 1.3%, respectively), surgical time (19.4 ± 5.1 and 19.1 ± 6.2 minutes, respectively), and postoperative discomfort scores (0.1 ± 0.3 and 0.2 ± 0.3, respectively), but these outcomes were significantly less favorable in the TM group. The results of this first comparative clinical trial suggest that femtosecond laser-assisted CAG preparation can be considered as an alternative technique for CAGs preparation.

Identification and Correction of Restrictive Strabismus After Pterygium Excision Surgery

PURPOSE

To report the characteristics of patients with restrictive diplopia following pterygium excision and a successful treatment approach for the strabismus.

DESIGN

Retrospective interventional case series.

METHODS

This study was set in a single academic institution and included 15 patients with restrictive diplopia after pterygium excision. Patients with any other reason for strabismus were excluded. Patients were evaluated for deficits with special attention to diplopic measures. The intervention was a combined procedure by a strabismologist and oculoplastic surgeon to correct the diplopia. The primary outcome measurements were subjective and objective improvement of diplopia.

RESULTS

Fifteen patients (mean age = 49 years) who developed diplopia after pterygium excision were included. Mean time to diplopia was 6 months. All patients had limited abduction in the previously operated eye causing esotropia in the abductive field (mean deviation = 18 prism diopters). After intervention, all patients were no longer diplopic in primary gaze. In the abductive field, 11 (73%) patients had residual small angle esotropia (mean = 7 prism diopters) in ipsilateral extreme end-gaze only. Only 2 patients required additional surgical intervention for scar tissue removal. No patients underwent medial rectus recession.

CONCLUSIONS

Restrictive diplopia is a potential complication after pterygium excision, particularly for patients with a history of recurrent pterygia requiring multiple excisions and previous amniotic membrane graft placement with fibrin glue. However, diplopia after pterygium excision in primary position is surgically correctable with scar tissue removal and ocular surface reconstruction, without needing medial rectus recession. Given the high volume of pterygium excision, awareness of postoperative restrictive strabismus and the potential for correction is critical.

Cauterisation versus fibrin glue for conjunctival autografting in primary pterygium surgery (CAGE CUP): study protocol of a randomised controlled trial

INTRODUCTION

Pterygium is a non-cancerous growth of the conjunctival tissue over the cornea that may lead to visual impairment in advanced stages, restriction of ocular motility, chronic inflammation and cosmetic concerns. Surgical removal is the treatment of choice, but recurrence of pterygium is a frequent problem. It has been previously shown that fibrin glue may result in less recurrence and may take less time than sutures for fixing the conjunctival graft in place during pterygium surgery. However, fibrin glue is a biological material and it carries the risk of transmitting infectious agents from pooled and single-donor blood donors and anaphylaxis in susceptible individuals. Cauterisation is another surgical option, and it would be advantageous to know whether cauterisation may be superior surgical option compared with fibrin glue. This protocol describes the rationale and design of the randomised controlled trial (RCT) in which we will compare cauterisation versus fibrin glue for conjunctival autografting in primary pterygium surgery.

METHODS AND ANALYSES

This will be a parallel group RCT comparing cauterisation versus fibrin glue for conjunctival autografting in primary pterygium surgery. Computer-generated randomisation will be used, and allocation concealment will be conducted using sequentially numbered opaque sealed envelopes. Surgeons will not be blinded to the procedures, but participants, other investigators and outcome assessors will be blinded. Adult participants with primary pterygium operated in a tertiary hospital in Split, Croatia, will be included. Primary outcome will be recurrence of pterygium, defined as any regrowth of tissue from the area of excision across the limbus onto the cornea after 180 days.

ETHICS AND DISSEMINATION

The trial was approved by the ethics review board of the University Hospital Split (500-03/17-01/68). Results will be disseminated at conferences and through peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT03321201; Pre-results.

Fibrin hydrogels as a xenofree and rapidly degradable support for transplantation of retinal pigment epithelium monolayers

Recent phase 1 trials of embryonic stem cell and induced pluripotent stem cell (iPSCs) derived RPE transplants for the treatment of macular degeneration have demonstrated the relative safety of this process. However, there is concern over clumping, thickening, folding, and wrinkling of the transplanted RPE. To deliver a flat RPE monolayer, current phase 1 trials are testing synthetic substrates for RPE transplantation. These substrates, however, cause localized inflammation and fibrosis in animal models due to long degradation times. Here we describe the use of thin fibrin hydrogels as a support material for the transplantation of RPE. Fibrin was formed into a mechanically rigid support that allow for easy manipulation with standard surgical instruments. Using fibrinolytic enzymes, fibrin hydrogels were degraded on the scale of hours. The rate of degradation could be controlled by varying the fibrinolytic enzyme concentration used. RPE cells degraded fibrin spontaneously. To preserve the fibrin support during differentiation of iPSCs to RPE, media was supplemented with the protease inhibitor aprotinin. iPSC-RPE on fibrin gels remained viable, generated monolayers with characteristic cobblestone appearance and dark pigmentation, and expressed mRNA and protein markers characteristic of RPE in the eye. Following differentiation of the cells, addition of fibrinolytic enzymes fully and rapidly degraded the fibrin support leaving behind an intact, viable iPSC-RPE monolayer. In conclusion, human fibrin hydrogels provide a xeno-free support on which iPSCs can be differentiated to RPE cells for transplant which can be rapidly degraded under controlled conditions using fibrinolytic enzymes without adverse effects to the cells.

STATEMENT OF SIGNIFICANCE

Stem cell-derived retinal pigment epithelial (RPE) cell transplantation is currently in phase 1 clinical trials for macular degeneration (MD). A major obstacle in these studies is delivering the RPE as a living, flat sheets without leaving behind foreign materials in the retina. Here we investigate the suitability of using hydrogels made from human blood-derived proteins for RPE transplant. Our data shows that these fibrin hydrogels are rigid enough for use in surgery, support growth of stem cell-derived RPE, and are easily degraded within hours without damage to the RPE sheet. These fibrin hydrogels offer a promising solution to transplant RPE for patients with MD.

Outcomes of pterygium surgery-glue versus autologous blood versus sutures for graft fixation-an analysis

AIM:

The aim of this study is to compare the surgical outcomes of pterygium excision with conjunctival autograft using sutures, fibrin glue (tisseel), and autologous blood for the management of primary pterygium.

PATIENTS AND METHODS:

A retrospective study done in 681 eyes with primary nasal pterygium. Excision of the pterygium was performed followed by closure of the bare sclera with conjunctival autograft using interrupted 10-0 monofilament nylon sutures in 173 eyes (Group 1), fibrin glue (tisseel-baxter healthcare corporation, westlake village, ca-91362 USA) in 351 eyes (Group 2), and autologous blood in 157 eyes (Group 3). Patients were followed up for a period of 5–52 months. During follow-up, graft-related complications such as recurrence, graft loss, graft retraction, granuloma if any were noted and compared among the three groups.

RESULTS:

A total of 681 eyes who had primary nasal pterygium were included in this study. Pterygium excision with conjunctival autograft was performed using 10-0 monofilament nylon interrupted sutures in 173 eyes (25.4%), tisseel fibrin glue in 351 eyes (51.54%), and autologous blood in 157 (23.05%) eyes. The mean duration of follow-up was 5–52 months. The overall recurrence rate was 2.9% (20 eyes). In Group 1, recurrence was seen in 5 eyes (2.89%), in Group 2, it was seen in 7 eyes (1.99%) and in Group 3, 8 eyes (5.10%). However, the recurrence rate was not significant (P = 0.160). The rate of graft retraction in the 3 study groups were 12 eyes (6.94%), 10 eyes (2.85%), and 56 eyes (35.67%) with a significant P < 0.001. Granuloma was seen in 2 eyes (1.16%), in Group 1, and in 1 eye (0.64%) in Group 3. Graft loss was seen in 3 eyes (1.73%), 4 eyes (1.14%), 6 eyes (3.82%) in Group 1, 2, and 3, respectively.

CONCLUSION:

The outcomes of the three most commonly performed surgical technique of conjunctival autograft fixation has shown us that all three techniques are equally comparable and can be offered to our patients with equally good results.