The influence of pterygium morphology on fibrin glue conjunctival autografting pterygium surgery

HIF1α and HIF2α immunoreactivity in epithelial tissue of primary and recurrent pterygium by immunohistochemical analysis

PURPOSE

Hypoxia-inducible factors (HIFs) are considered to play a significant role in the pathogenesis of pterygium. The aim of this study was to investigate the relative expression or immunoreactivity of HIF1α and HIF2α in the epithelium of primary pterygium, recurrences and healthy conjunctiva.

METHODS

Immunohistochemical staining was performed with antibodies against HIF1α and HIF2α, respectively, on 55/84 primary pterygium specimens, 6/28 recurrences and 20/20 control tissues (healthy conjunctiva).

RESULTS

Immunohistochemical staining revealed lower epithelial immunoreactivity of HIF1α and HIF2α in both primary pterygium (11% and 38%) and recurrences (18% and 21%) when compared to healthy conjunctival tissue (46% and 66%). Differences between immunoreactivity of HIF1α and of HIF2α in primary pterygium and controls were each highly significant (p < .001). Within the group of primary pterygium, epithelial immunoreactivity of HIF2α (38%) was significantly higher than that of HIF1α (11%). In recurrent pterygium and healthy conjunctiva, immunoreactivity levels of HIF2α were higher than those of HIF1α as well; however, differences between both isoforms were not significant.

CONCLUSION

Our study shows evidence that the higher expressed epithelial HIF2α, rather than HIF1α, and the balance between both HIF isoforms might be relevant factors associated with pathogenesis of primary pterygium. Modulation of HIF2α levels and activity may thus offer a new therapeutic approach to the treatment of advancing pterygium where the initial stage with its HIF1-peak has already passed.

Postsurgery Classification of Best-Corrected Visual Acuity Changes Based on Pterygium Characteristics Using the Machine Learning Technique

Introduction

Early detection of visual symptoms in pterygium patients is crucial as the progression of the disease can cause visual disruption and contribute to visual impairment. Best-corrected visual acuity (BCVA) and corneal astigmatism influence the degree of visual impairment due to direct invasion of fibrovascular tissue into the cornea. However, there were different characteristics of pterygium used to evaluate the severity of visual impairment, including fleshiness, size, length, and redness. The innovation of machine learning technology in visual science may contribute to developing a highly accurate predictive analytics model of BCVA outcomes in postsurgery pterygium patients.

Aim

To produce an accurate model of BCVA changes of postpterygium surgery according to its morphological characteristics by using the machine learning technique. Methodology. A retrospective of the secondary dataset of 93 samples of pterygium patients with different pterygium attributes was used and imported into four different machine learning algorithms in RapidMiner software to predict the improvement of BCVA after pterygium surgery.

Results

The performance of four machine learning techniques were evaluated, and it showed the support vector machine (SVM) model had the highest average accuracy (94.44% ± 5.86%), specificity (100%), and sensitivity (92.14% ± 8.33%).

Conclusion

Machine learning algorithms can produce a highly accurate postsurgery classification model of BCVA changes using pterygium characteristics.

Healing of autologous conjunctival grafts in pterygium surgery

PURPOSE

To temporally study the healing of conjunctival autografts in consecutive patients following pterygium surgery.

METHODS

A case-cohort observational study. Thirty-two eyes of 28 patients who underwent pterygium surgery were included. All eyes had pterygium excision with conjunctival autografts. Twenty-seven eyes of 24 patients underwent excision of primary pterygium while five eyes of four patients had surgery for recurrent pterygium. All grafts were attached using fibrin glue. Mitomycin-C 0.04% was used intraoperatively in 25 eyes. All eyes were followed up at 1, 2, 4, 8, 12 weeks and 6 months postoperatively. Photographs were taken at each visit to monitor graft vessels, re-perfusion and healing. Main outcome measures were graft loss; re-perfusion of grafts and appearance and resolution of oedema, transudation and haemorrhage; approximation of graft edges to host bed and changes at donor site.

RESULTS

No graft tissue was lost. In all eyes, healing of autografts started with graft swelling due to oedema and transudation followed by re-perfusion injury, which manifested as swelling, variable vessels calibre, patchy or diffuse haemorrhage occurring within first week and resolving by fourth postoperative week. Graft vessels anastomose with vessels in surrounding conjunctiva and underlying episclera to re-establish blood circulation. Retraction of graft edges from surrounding conjunctiva was uncommon with rapid epithelialization of exposed (epi)sclera.

CONCLUSION

Conjunctival autografts in pterygium surgery follow a consistent healing pattern dominated by re-perfusion injury in early postoperative days. This produces dramatic changes in the autograft for which patients should be counselled before surgery. Conjunctival autografts are not at risk of falling off, losing epithelial cover or undergoing necrosis.

How to minimize pterygium recurrence rates: clinical perspectives

The main treatment for pterygium is surgical removal. However, pterygium surgery is concerned with high rates of postoperative recurrence. Predicting factors of recurrence are not fully understood, yet, but they probably depend on a multitude of patient-related, clinical, and/or surgical factors. Several adjuvant treatments have been proposed to reduce postoperative pterygium recurrence, including different antimetabolites, antiangiogenetic factors, and radiation therapy. The purpose of this review is to collect the current evidence regarding application and limits of different therapeutic approaches for preventing postoperative recurrence of pterygium, giving insights and perspectives for better management of this disease. In the light of the current evidence, pterygium surgery cannot disregard wound coverage with conjunctival autografting or rotational flap combined with adjuvant treatments. The rotational flap technique is associated with shorter surgical time rates and prevents graft displacement and necrosis, given its vascular pedicle. Amniotic membrane may still be reserved in case of great conjunctival defects or insufficient conjunctiva. Repeated subconjunctival antivascular endothelial growth factor injections can be considered as an effective and safe adjuvant treatment. Moreover, management of postoperative pain is crucial. Innovative treatment strategies will probably target different molecular pathways, considering recent findings regarding pterygium pathogenesis, to improve better understanding and develop universally shared guidelines. Great importance shall be dedicated to the identification of novel molecular biomarkers and favoring factors of recurrence, in order to achieve a customized surgical treatment for each patient and obtain maximal reduction of postoperative recurrence.

Clinical results for combination of fibrin glue and nasal margin suture fixation for attaching conjunctival autografts after pterygium excision in Chinese pterygium patients

This study was designed to compare postoperative complications and postoperative discomfort when using glue combined with nasal margin suture fixation versus fibrin glue or sutures alone to attach conjunctival autografts among Chinese patients during pterygium excisions.We analyzed the medical records of 150 eyes of 150 patients with primary pterygium, in which the autografts were secured by 3 different methods after pterygium excision: 50 eyes were secured with fibrin glue, 50 eyes were secured with glue + nasal sutures, and 50 eyes were secured with sutures. The more than 6 months of follow-up observation data included postoperative complications (graft loss/displacement, dehiscence, proliferative granuloma, inflammation, and hemorrhage), recurrence, and postoperative discomfort. A logistic regression procedure was conducted to evaluate the relationship between graft complications and the pterygium grade.Graft loss/displacement occurred in 3 patients (6%) in the glue group. Graft dehiscence occurred in 8 patients (16%) in the glue group (P < .001), with 2 developing into proliferative granuloma, compared with none in the glue + nasal sutures group and the sutures group at the 3-month postoperative follow-up. Pterygium recurrence occurred in 1 patient (2.2%) in the glue group and 2 patients (4.4%) in the sutures group, compared with none in the glue + nasal sutures group at the 6 to 9 month postoperative follow-up (P = .315). There were fewer postoperative symptoms (pain, foreign body sensation, and tearing) at days 1 and 7 in the fibrin glue and glue + nasal sutures groups than in the sutures group (P < .01). The pterygium grade was a significant risk factor for graft complications (Odd ratio, OR: 5.98, Confidence interval, CI: 1.193-29.992, P = .03) in the glue group.The modified conjunctival autograft fixation with glue + sutures on the nasal margin resulted in more stable grafts and less graft-associated complications. There was a low level of postoperative patient discomfort in the glue + sutures group. A higher grade of pterygium led to an increased rate of complications in the glue group.

Effect of single subconjunctival injection of bevacizumab on primary pterygium: clinical, histopathological and immunohistochemical study

AIM

To evaluate the effect (clinically, histopathologically and immunohistochemically) and safety of a single intra-pterygium injection of bevacizumab.

METHODS

Prospective interventional study comprised 40 eyes of 40 patients with primary fleshy pterygia who attended the Outpatient Clinic of Department of Ophthalmology, Assiut University Hospitals, Egypt from May 2015 to May 2016. Patients were randomly classified into 2 groups: the first group received a single intralesional injection of bevacizumab (Avastin; Genentech, San Francisco, CA, USA); the second group comprised patients who did not receive subconjunctival bevacizumab. Excision of pterygium and conjunctival auto graft was done in both groups. The excised pterygium tissues were subjected to histopathological and immunohistochemical evaluation.

RESULTS

The study comprised 40 eyes of 40 patients (33 men, 7 women) of age range from 31-58y. The study group included 22 eyes. The control group included 18 eyes. A decrease in the vascularity of the pterygium was noted in all injected cases. The mean vessel count was higher in non-injected pterygia than that in injected pterygia and the difference was statistically significant (P=0.001). Also, the mean vessel count in both groups was significantly higher than normal conjunctive (P=0.005 and 0.001). A statistically significant difference in vascular endothelial growth factor (VEGF) expression between injected and non-injected cases was detected in the epithelial, stromal and endothelial cells (P=0.0001, 0.016, 0.014). No serious intraoperative complications occurred in both groups.

CONCLUSION

The use of single intra lesional injection of Avastin in pterygium decreased vascularity and decreased VEGF expression in injected pterygium after one month. Our study proved the effect of single intra lesional injection of Avastin on pterygium. Further studies may enable limiting the need for surgery and improve quality of life for patients with pterygia.

Fibrin glue conjunctival autograft for primary pterygium: Overall outcomes and outcomes in expert versus trainee ophthalmologists

INTRODUCTION

To determine outcomes of conjunctival autograft attached with fibrin glue (FG) for primary pterygium, and compare these outcomes in expert versus closely supervised trainee ophthalmologists.

METHODS

This was a retrospective, comparative, non-randomized, interventional study. Patients were recruited among those with primary nasal pterygium undergoing FG conjunctival autograft. Surgery was performed by expert (136 eyes) or closely supervised trainee (128 eyes) ophthalmologists. Mean follow-up was 7.82±8.23months. Main outcome measures were recurrence rate, reoperation rate and complications.

RESULTS

The study sample comprised 264 eyes of 225 patients. Participants were of mean age 47.09±12.89years; 46.7% were male, 28.4% Caucasian and 70.5% Hispanic. Recurrence was recorded in 6.4%: 5.9% in the expert group and 7% in the trainee group (P=0.704) and reoperation in 1.9%: 0.7% and 3.1% (P=0.202), respectively. Both groups showed similar rates of complications such as transient graft edema, graft dehiscence, hematoma or ocular hypertension. Reoperation was slightly more frequent in patients younger than 40years (P=0.064).

CONCLUSIONS

Good outcomes were observed for FG conjunctival autografting in primary pterygium surgery, with no differences recorded between supervised trainee and expert surgeons. Our findings suggest the need to supervise pterygium surgeries during training.

Anti-fibrotic, anti-VEGF or radiotherapy treatments as adjuvants for pterygium excision: a systematic review and network meta-analysis

Background

Anti-fibrotic, anti-VEGF (vascular endothelial growth factor) medications, or radiotherapy, as adjuvant for pterygium surgical procedure, has been suggested for reducing recurrence, but difficulties may be experienced in deciding which treatment to use. The purpose of this study was to compare the efficacies of these different adjuvants for preventing recurrence following pterygium surgery.

Methods

We conducted a systematic review to identify randomized controlled trials of patients with primary or recurrent pterygium who received anti-fibrotic, anti-VEGF medication, or radiotherapy as adjuvants in combination with surgical procedure. The surgical procedure contained bare sclera technique or petrygium excision combination with tissue grafting. The primary outcome of this study was recurrence. Direct-comparison and Bayesian network meta-analyses were performed to assess direct and indirect evidence of efficacy.

Results

We obtained data from 34 randomized controlled trials, representing a total of 2483 patients. Adjuvants included bevacizumab, 5-FU (5-fluorouracil), MMC (mitomycin C), and β-RT (beta-radiotherapy). Compared with placebo, we found distinguishable improvement in recurrence with bevacizumab (odds ratio [OR] 0.38, 95% confidence interval [CI] 0.18–0.80), MMC (0.12, 95% CI 0.06–0.21), and β-RT (0.17, 95% CI 0.04–0.69), but not with 5-FU (0.41, 95% CI 0.12–1.39). MMC significantly reduced recurrence when compared to bevacizumab (0.31, 95% CI 0.13–0.77) and 5-FU (0.28, 95% CI 0.08–0.99). The probability of having the most recurrences after excision was lowest for MMC, followed by bevacizumab and β-RT. Similar results were found in subgroup analyses, including for primary pterygium, and the patients receiving bare sclera technique or conjunctival autograft.

Conclusions

Adjuvants such as MMC, bevacizumab, and β-RT could effectively prevent recurrence following pterygium excision. However, their efficacy and acceptability require further clarification in future randomized controlled trials.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0601-5) contains supplementary material, which is available to authorized users.

Egg Albumen as a Fast and Strong Medical Adhesive Glue

Sutures penetrate tissues to close wounds. This process leads to inflammatory responses, prolongs healing time, and increases operation complexity. It becomes even worse when sutures are applied to stress-sensitive and fragile tissues. By bonding tissues via forming covalent bonds, some medical adhesives are not convenient to be used by surgeons and have side effects to the tissues. Here egg albumen adhesive (EAA) is reported with ultrahigh adhesive strength to bond various types of materials and can be easily used without any chemical and physical modifications. Compared with several commercial medical glues, EAA exhibits stronger adhesive property on porcine skin, glass, polydimethylsiloxane. The EAA also shows exceptional underwater adhesive strength. Finally, wound closure using EAA on poly(caprolactone) nanofibrous sheet and general sutures is investigated and compared in a rat wound model. EAA also does not show strong long-term inflammatory response, suggesting that EAA has potential as a medical glue, considering its abundant source, simple fabrication process, inherent nontoxicity, and low cost.

Clinical analysis of risk factors contributing to recurrence of pterygium after excision and graft surgery

AIM

To find the risk factors related to the reproliferation of the pterygial tissue after excision and graft surgery.

METHODS

Charts of 130 eyes of 130 patients who had pterygial excision from March 2006 to April 2011 were reviewed. Preoperative pterygium morphology, surgical methods, and adjunctive treatments were statistically analyzed for their relationship with recurrence.

RESULTS

During the follow-up period, recurrence was observed in 20 eyes (15.4%). None of the preoperative morphologic features were affected the rate of the recurrence. However, an age < 40y [P =0.085, odds ratio (OR) 3.609, 95% confidence interval (CI) 0.838-15.540] and amniotic membrane graft instead of conjunctival autograft (P =0.002, OR 9.093, 95% CI 2.316-35.698) were statistically significant risk factors for recurrence. Multivariate analysis revealed that intraoperative mitomycin C (MMC) (P=0.072, OR 0.298, 95% CI 0.080-1.115) decreased the rate of recurrence.

CONCLUSION

Younger age is a risk factor for reproliferation of pterygial tissue after excision and amniotic membrane transplantation (AMT) are less effective in preventing recurrence of pterygium after excision based on the comparison between conjunctival autograft and AMT. Intraoperative MMC application and conjunctival autograft reduce recurrence.