Prospective Study on the Safety and Efficacy of Combined Conjunctival Rotational Autograft With Intraoperative 0.02% Mitomycin C in Primary Pterygium Excision

Automated histopathological evaluation of pterygium using artificial intelligence

PURPOSE

This study aimed to evaluate the efficacy of a new automated method for the evaluation of histopathological images of pterygium using artificial intelligence.

METHODS

An in-house software for automated grading of histopathological images was developed. Histopathological images of pterygium (400 images from 40 patients) were analysed using our newly developed software. Manual grading (I-IV), labelled based on an established scoring system, served as the ground truth for training the four-grade classification models. Region of interest segmentation was performed before the classification of grades, which was achieved by the combination of expectation-maximisation and k -nearest neighbours. Fifty-five radiomic features extracted from each image were analysed with feature selection methods to examine the significant features. Five classifiers were evaluated for their ability to predict quantitative grading.

RESULTS

Among the classifier models applied for automated grading in this study, the bagging tree showed the best performance, with a 75.9% true positive rate (TPR) and 75.8% positive predictive value (PPV) in internal validation. In external validation, the method also demonstrated reproducibility, with an 81.3% TPR and 82.0% PPV for the average of four classification grades.

CONCLUSIONS

Our newly developed automated method for quantitative grading of histopathological images of pterygium may be a reliable method for quantitative analysis of histopathological evaluation of pterygium.

[Pterygium: pathogenesis, diagnosis and treatment]

The pterygium is a frequent ultraviolet (UV) light-induced focal fibrovascular proliferation of the conjunctival tissue onto the cornea. Surgical excision should be performed in the case of reduced visual acuity, progressive astigmatism, impending invasion of the optical axis and ocular surface complaints. The main factors in preventing recurrence include optimal surgical treatment by an excision combined with a free conjunctival autograft, consistent postoperative treatment with preservative-free artificial tears and topical steroids as well as long-term UV protection.

Role of oxidative stress and vascular endothelial growth factor expression in pterygium pathogenesis and prevention of pterygium recurrence after surgical excision

PURPOSE

To assess the roles of oxidative stress and vascular endothelial growth factor (VEGF) in pterygium pathogenesis and prevention of pterygium recurrence after surgical excision.

METHODS

Surgically removed pterygium tissue from 35 pterygium patients and normal conjunctival samples from 15 patients matched for age and sex (used as controls) constituted the study samples. The conjunctival samples were preserved at - 80 °C until analysis. Catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH) and total antioxidant (TAO) enzymatic activity and the levels of nitric oxide (NO), malondialdehyde (MDA) and VEGF were studied in both groups. To evaluate the recurrence rate after surgical excision, the pterygium patients were further subdivided into three groups according to the adjuvant therapy used to prevent recurrence. Group 1 consisted of 10 patients who were treated with 0.2 mg mitomycin-c (MMC) for 2 min. Group 2 consisted of 12 patients treated with subconjunctival bevacizumab injection after surgical removal of the pterygium. Group 3 consisted of 13 patients who underwent combined treatment with 0.2 mg of MMC for 2 min and subconjunctival bevacizumab injection. The follow-up of patients in the three groups ranged from 7 to 15 months.

RESULTS

The activities of CAT, SOD, GSH and TAO were significantly lower in pterygium samples than in normal conjunctival samples (p < 0.0001 each). The levels of MDA (p = 0.046), NO (p < 0.0001) and VEGF (p < 0.0001) were significantly higher in pterygium patients than in controls. The lowest recurrence rate after surgical excision was that of the third group.

CONCLUSIONS

Oxidative stress and VEGF could play a role in the pathogenesis of pterygium as indicated by decreased antioxidant enzymatic activity and increased levels of VEGF in the pterygium tissue and the role of MMC and anti-VEGF therapy in decreasing the recurrence rate after surgical excision.

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.

Surgical outcome of conjunctival rotational autograft-mitomycin C (MMC) versus free conjunctival autograft-MMC for pterygium removal: A randomized clinical trial

Background

Pterygium is a common degenerative eye disease. Despite various surgical methods to treat pterygium, recurrence is the main complication. The main issue is finding a surgical method with the lowest recurrence.

Objective

to compare the complications, recurrence rate and the cosmetic effects of two surgical techniques, namely conjunctival rotation autograft (CRA) and conjunctival autograft (CA), in treating pterygium.

Methods

This randomized clinical trial was conducted at Khalili Hospital in Shiraz, Iran, from January to August 2015. Forty-five eyes from 45 patients were studied. The patients were randomly divided into two groups using the blocking method. The patients of one group were operated on by the CRA technique, while the other group was operated on by the CA method. The patients were checked for the recurrence of pterygium, and other complications at the end of the first, third, and sixth month. Finally, the data were analyzed using SPSS version 21.

Results

The mean age of the patients was 42.5 years. The recurrence of pterygium was not observed in any of the patients 6 months after the surgery. Following 6 months after the operation, graft retraction occurred during the first week for one patient (4.5%) in the CA group, and five patients (21.7%) in the CRA group. The prevalence rate of graft injection among the patients of the CA and CRA groups 6 months after the operation was 9.1% and 65.2%, respectively. There was a significant correlation between injection intensity and the dissatisfaction of the patients with the operation’s outcome (p=0.017).

Conclusion

CRA with mitomycin is considered as an effective method to reduce the recurrence of pterygium after operation. This technique can be used as an acceptable method for pterygium operation, especially for patients with insufficient conjunctiva.

Clinical trial registration

The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the Irct ID: IRCT2016092119581N2.

Funding

The study was financially supported by Shiraz University of Medical Sciences (SUMS) (grants No. 8901).

Pterygium surgery using the principle of contact inhibition: results of 13 years' experience

Purpose

To report a technique to prevent pterygium recurrence using the principle of contact inhibition.

Methods

Two hundred and fifteen patients (232 eyes; average age, 64.1 years) with primary pterygia who underwent pterygium surgery at the Hara Eye Hospital between 1999 and 2012. We retrospectively evaluated the patients who underwent the following procedure to prevent pterygium recurrence. The surface conjunctiva on the pterygium body was not removed. After removing the pterygium body, by placing a narrow pedicle autoconjunctival flap along the corneal limbus and tying it tightly to the front area of the residual conjunctiva, there is no room for the active residual tissue to proliferate, thus preventing a recurrence by contact inhibition. The key factor is conjunctival suturing, which establishes face-to-face contact of both areas of cut conjunctival tissue. Mitomycin C is applied locally for 3 min intraoperatively and 5 days postoperatively. The main outcome measure was the prevention of pterygium recurrence using this technique.

Results

By the end of the average follow-up of 5 years 4 months, three eyes (1.3%) had a recurrence. Among the 232 eyes, 23 eyes had large pterygia extending to the pupillary area. Using the surgical technique, there were no recurrences. No specific characteristic of the recurrence was found in association with the eye, sex, and preoperative grade.

Conclusions

This surgery has three relevant features: (1) reconfirmation of the effect of contact inhibition, (2) the anatomic structure of the conjunctival sac scarcely changes postoperatively, because the surface conjunctiva of the pterygium body is not removed, and (3) a low recurrence rate.

Electronic supplementary material

The online version of this article (doi:10.1007/s00417-016-3558-9) contains supplementary material, which is available to authorized users.

Mitomycin C in pterygium treatment

Pterygium is a benign lesion usually growing from the nasal side of the conjunctiva onto the cornea. Most cases of pterygium does not cause problem or requires specific treatment. The exact cause of pterygium is not clear yet, but some factors are pointed as causes, being the most important the long-term ultraviolet ray exposure. Pterygium surgery is usually considered when there are symptoms that do not respond to conservative treatment. Recurrence is the main complication of the surgery, and much has been done to avoid it. Mitomycin C (MMC) has been used as a fibroblast proliferation inhibitor during the surgery to reduce the chance of recurrence of the pterygium. This review describes the use of MMC as an adjunctive, the optimal dosage, the duration of administration of MMC and possible complications, when used during, after and before the surgery. Most studies suggest that increased exposure (dose or duration) of MMC is associated with a lower recurrence, but with higher risks of complications.

Conjunctival Rotation Autograft for Pterygium: An Alternative to Conventional Conjunctival Autografting

PURPOSE

To determine the safety and efficacy of conjunctival rotation autograft (CRA) as an alternative to conventional conjunctival autograft after pterygium excision and its complications and rate of recurrence.

DESIGN

A prospective non-comparative interventional case study.

METHODS

Conjunctival rotation autograft was performed under peribulbar block in 50 eyes with primary pterygium as well as recurrent pterygium of grade 1, 2 and 3 according to a morphological grading system. Patients were followed up for 12 months for complications like graft retraction, injection, recurrence, etc.

RESULTS

A total of 55 CRAs were done in 50 eyes of 47 subjects in the study wherein grafts were attached by using the 10-0 nylon sutures in primary and recurrent pterygia. Mean follow up period was 11.67 months (Range 9-12 months). The most commonly found complications were graft injection in 16 (29.09%) cases and graft pigmentation in 5 (9.0%) cases. Injection was not associated with pterygium grade and was found to be statistically insignificant (P = 0.27). Recurrence was found only in 1 (1.8%) case in grade T3 recurrent pterygium.

CONCLUSIONS

Conjunctival rotation autograft appears to be a successful and safe alternative to conjunctival autograft, with a relatively low rate of pterygium recurrence in this uncontrolled series. We advocate the use of CRA for cases of pterygium in which a conventional autograft is contraindicated or difficult. In addition, the procedure can be used as a primary surgical option in primary and recurrent pterygia.

Recurrence and complications after 1,000 surgeries using pterygium extended removal followed by extended conjunctival transplant

OBJECTIVE

To document the recurrence rate and complication rate of pterygium extended removal followed by extended conjunctival transplant.

DESIGN

An open, prospective study of consecutive pterygium patients undergoing pterygium extended removal followed by extended conjunctival transplant.

PARTICIPANTS AND CONTROLS

The study included 1000 consecutive patients undergoing pterygium surgery between August 2001 and September 2009.

INTERVENTIONS

All patients underwent pterygium extended removal followed by extended conjunctival transplant by the author with attempted follow-up for 1 year.

MAIN OUTCOME MEASURES

Recurrence and complication rates.

RESULTS

Follow-up of >1 year was obtained in 99% of patients. There was 1 recurrence in the 1000 surgeries (0.1%) with 95% confidence intervals of 0.003%-0.56% (Fischer exact test). Seven patients required further surgery: 3 had graft replacements, and 1 each for recurrence, strabismus, inclusion cyst, and granuloma. One patient lost 4 lines of vision from a corneal ulcer.

CONCLUSIONS

Pterygium extended removal followed by extended conjunctival transplant results in one of the lowest recurrence rates reported in the world's literature and an acceptable complication rate.

Preoperative subpterygeal injection vs intraoperative mitomycin C for pterygium removal: comparison of results and complications

PURPOSE

To evaluate and compare the recurrence rates and complications between 2 therapeutic methods for primary pterygium: subconjunctival injection of mitomycin C (MMC) 1 month before bare scleral excision and conjunctival rotational flap with intraoperative MMC use.

DESIGN

Prospective, interventional, randomized clinical trial.

METHODS

setting: Institutional clinical trial in a tertiary, specialty eye hospital. study population and intervention: We included 82 eyes diagnosed with primary pterygium and randomly allocated them into 2 groups. Group A consisted of 36 eyes treated with subconjunctival injection of 0.02% MMC 1 month before bare scleral excision, and group B comprised 46 eyes that underwent conjunctival rotational flap with intraoperative 0.02% MMC for 2 minutes. Follow-up periods were at least 12 months (range, 12 to 18 months). main outcome measure: Recurrence and complication rate in each arm of study.

RESULTS

During the 1-year follow-up, 2 cases of clinical recurrence in third and sixth month of follow-up occurred in group B (recurrence rate, 4.3%). In group A, there was no clinically significant recurrence, but 2 cases of hypovascularity and whitening of sclera at the site of pterygium excision was observed. There was no other serious complication. There was no statistically significant difference between groups for recurrence rate, mean age, sex, or pterygium area.

CONCLUSIONS

Subconjunctival injection of MMC 0.02% (0.1 ml of 0.02% solution) 1 month before bare scleral excision is a quick, easy, and safe surgical procedure and is at least as effective as conjunctival rotational flap with intraoperative MMC for 2 minutes.