The recurrence of pterygium after different modalities of surgical treatment

Recurrent pterygium: A review

Purpose:

To summarize the recent evidence regarding different aspects of pterygium recurrence.

Methods:

Human-based studies from PubMed, Scopus, and Google Scholar were identified using the following keywords: conjunctival disease, pterygium, recurrent pterygium, pterygium recurrence, pterygium management/surgery, conjunctival autograft (CAU), amniotic membrane graft/transplant, and adjuvant therapy (January 2009 to February 2021). We reviewed risk factors associated with the recurrence of pterygium, timing of recurrence, medical treatments to prevent from recurrence, and nonsurgical and surgical alternatives for management of recurrence.

Results:

Dry eye disease, black race, and young age are considered definite risk factors for recurrence. However, fleshy appearance of the pterygium and preoperative size remain controversial. Surgical techniques such as excessive suturing, insufficient conjunctival graft size, thick conjunctival graft with remained Tenon tissue, and postoperative graft retraction are considered possible risk factors for recurrence. Using fibrin glue instead of sutures can further reduce recurrence rates. Although recurrence could occur even after many years, most recurrences happen in the first 3–6 months after surgery. Multiple kinds of adjuvant medications are used before, during, or after the operation including mitomycin C (MMC), 5-fluorouracil (5-FU), corticosteroids, and anti-vascular endothelial growth factors (anti-VEGFs). Multiple weekly subconjunctival 5-FU injections are shown to be safe and effective in halting the progression of recurrent pterygium. Although topical bevacizumab is found to inhibit the growth of impending recurrent pterygium, the effect is mostly temporary. CAU is superior to amniotic membrane transplantation in the treatment for recurrent pterygia.

Conclusions:

There is yet to be a panacea in treating recurrent pterygium. Currently, there is not a globally accepted recommendation for treating recurrent pterygium with anti-VEGFs or 5-FU as a nonsurgical treatment. We strongly recommend using MMC as an adjunct to surgery in recurrent cases, with consideration of its specific complications. CAU is the most effective surgical treatment for recurrent pterygium, and other new surgical therapies need further investigation.

The in vitro anti-fibrotic effect of Pirfenidone on human pterygium fibroblasts is associated with down-regulation of autocrine TGF-β and MMP-1

We aimed to investigate the in vitro effect of pirfenidone (PFD) on proliferation, migration and collagen contraction of human pterygium fibroblasts (HPFs). HPFs were obtained from tissue explants during pterygium surgery. After treatment with pirfenidone, the HPFs proliferation was measured by MTT, cell cycle progression measured by flow cytometry, cell migration measured by the scratch assay, and cell contractility evaluated in fibroblast-populated collagen gels. The expression of TGF-β1, TGF-β2, MMP-1 and TIMP-1 were also determined with quantitative PCR, western blot and immunofluorescence staining. Results showed pirfenidone markedly inhibited HPFs proliferation with an IC₅₀ of approximately 0.2 mg/ml. After treatment with 0.2 mg/ml pirfenidone for 24 hours, HPFs were at G0/G1 cell cycle arrest, with significantly reduced cell migration capability and collagen contraction, decreased mRNA and protein expressions of TGF-β1, TGF-β2 and MMP-1, and no alterations of TIMP-1 expression. Thus, we have concluded that pirfenidone at 0.2 mg/ml inhibits proliferation, migration, and collagen contraction of HPFs, which is associated with decreased expression of TGF-β and MMP-1, and pirfenidone might represent a potentially therapeutic agent to prevent the recurrence of pterygium after surgery.

Interferon Alpha-2b Eye Drops Prevent Recurrence of Pterygium After the Bare Sclera Technique: A Single-Center, Sequential, and Controlled Study

To investigate the efficacy and safety of interferon (IFN) alpha-2b eye drops in preventing pterygium recurrence after the bare sclera technique.

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.

Comparison among adjuvant treatments for primary pterygium: a network meta-analysis

PURPOSE

Pterygium is a frequent ocular disease, where the major challenge is the high level of recurrence after its surgical removal. We performed a network meta-analysis to identify, among several adjuvant treatments for primary pterygium, which is the best to prevent recurrence.

METHODS

A search was conducted using PubMed, Scientific Electronic Library Online, Latin American and Caribbean Centre on Health Sciences and Cochrane Eyes and Vision Group Trials Register between 1993 and 2015 for randomisedclinical trials (RCTs) comparing adjuvant treatments following primary pterygium surgery.

RESULTS

24 RCTs that studied 1815 eyes of 1668 patients were included and allowed direct and indirect comparison among 14 interventions through network meta-analysis. The rank from the best to worse treatment to prevent recurrence is: conjunctival autograft + ciclosporin 0.05% eye drops, bare sclera + intraoperativemitomycin C (MMC) <0.02%, bare sclera + beta therapy (2500 cGy single dose), conjunctival autograft + beta therapy (1000 cGy single dose), bare sclera + MMC 0.02% eye drops, conjunctival autograft, bare sclera + intraoperative MMC >0.02%, bare sclera + ciclosporin 0.05% eye drops, bare sclera + intraoperative 5-fluorouracil 5%, amniotic membrane transplantation, bare sclera + intraoperative MMC 0.02%, conjunctival autograft + bevacizumab 0.05% eye drops, bare sclera + bevacizumab 0.05% eye drops and bare sclera alone.

CONCLUSION

The best adjuvant treatment to prevent recurrence after primary pterygium surgery is the association of conjunctival autograft and ciclosporin 0.05% eye drops. Bare sclera technique alone should be discontinued since it is associated with high recurrence rates.

Conjunctival Autograft Versus Amniotic Membrane Transplantation for Treatment of Pterygium: Findings From a Cochrane Systematic Review

PURPOSE

To summarize key findings from a systematic review of the effectiveness and risks of conjunctival autograft (CAG) compared with amniotic membrane transplant (AMT) for pterygium.

DESIGN

Cochrane systematic review.

METHODS

We included only randomized controlled trials (RCTs) in which CAG and AMT had been compared for primary or recurrent pterygia. The primary outcome was recurrence of pterygium ≥1 mm onto the cornea by 3 and 6 months post surgery. We adhered to Cochrane methods for trial selection, data extraction, risk of bias evaluation, and data synthesis.

RESULTS

Twenty RCTs with 1866 participants (1947 eyes) were included. Pterygium recurrence 6 months after surgery ranged from 3.3% to 16.7% in the CAG group and 6.4% to 42.3% in the AMT group based on data from 1021 eyes in 10 RCTs. Estimated risk ratios from meta-analysis indicated that CAG-treated eyes had a 47% lower risk of recurrence 6 months after surgery compared with the AMT group (RR, 0.53, 95% confidence interval [CI], 0.33-0.85). For 96 eyes with recurrent pterygium, the risk of recurrence 6 months after CAG was reduced by 55% compared with AMT (risk ratio [RR], 0.45, 95% CI, 0.21-0.99). Three-month recurrence rates were similar for CAG and AMT based on data from 538 eyes (6 RCTs).

CONCLUSIONS

CAG was more effective than AMT to prevent pterygium recurrence by 6 months post surgery, especially in recurrent pterygia. CAG-treated eyes had half the recurrence rates of AMT-treated eyes. Future RCTs should assess changes in patient-reported outcomes (symptoms, cosmesis) and visual acuity, and evaluate effects of surgical variations.

Limbal conjunctival versus amniotic membrane in the intraoperative application of mitomycin C for recurrent pterygium: a randomized controlled trial

PURPOSE

This study compared the outcomes of a limbal conjunctival autograft (LCAG) with those of an amniotic membrane graft (AMG) followed by intraoperative 0.02 % mitomycin C (MMC) to treat recurrent pterygium.

METHODS

In this randomized controlled trial, ninety-six eyes with recurrent pterygium were enrolled and randomly allocated into two groups using a computer-generated random number table. Pterygium removal was followed by intraoperative 0.02 % MMC for 3 min and then either LCAG or AMG transplantation. The major outcomes were recurrence rate, conjunctival inflammation grade, healing time of the corneal epithelial defect, eye-movement amplitude (EMA), uncorrected distance visual acuity (UDVA), and complications.

RESULTS

A follow-up of 12 months was conducted for 93 eyes of 82 patients. Grade D (recurrence) presented in one eye of the LCAG group and five eyes of the AMG group, with no between-group difference (p = 0.196). However, Grades A, B, and C presented in 46, zero and zero eyes of the LCAG group respectively, and in 37, two and two eyes of the AMG group respectively, with the surgical bed generally showing a better appearance in the LCAG group than in the AMG group (p = 0.008). Compared with baseline values, the postoperative EMA improved significantly in both groups (p < 0.001 for the LCAG group; p = 0.001 for the AMG group), as did UDVA (p = 0.005 for the LCAG group; p = 0.012 for the AMG group). No between-group differences were found in terms of the healing time for epithelial defect, conjunctival inflammation grade, or the frequency of complications such as punctate epithelial keratitis, episcleral melting, corneal pannus, and delayed corneal epithelium healing.

CONCLUSIONS

LCAG transplantation with intraoperative 0.02 % MMC is as efficacious in treating recurrent pterygium as AMG transplantation with MMC. The former procedure results in an attractive cosmetic appearance but might result in limbal damage in some eyes. The surgeon's familiarity with these procedures should determine the method of treatment.

Safety and efficacy of human amniotic membrane in primary pterygium surgery

Grafts made from human amniotic membrane are used to prevent recurrence of pterygium after excision. The success of the procedure can be affected by the quality of preparation and preservation of the grafts. We prospectively evaluated the safety and efficacy of cryopreserved amniotic membrane prepared at the research tissue bank of the Biotechnology Research Center in Tripoli, Libya, and used as adjunct therapy in primary pterygium excision. Twenty-six patients (15 males and 11 females) aged 21-78 years and indicated for primary pterygium excision were transplanted at the Tripoli Eye Hospital with the amniotic membrane grafts. Sixteen patients (62 %) were available for all three follow-up visits scheduled at 1, 3 and 6 months post-surgery. By the third visit, two patients (12.5 %) developed granuloma and three (18.8 %) had pterygium recurrence. The grafts were used after cryopreservation for ≤180 days or >180 days, but statistical analysis showed that the complications were not associated with the length of storage. Moreover, the high rate of complications in this study was not caused by use of cryopreserved AM. In conclusion, locally produced cryopreserved AM is safe as an adjunct therapy for treatment of primary pterygium excision.

Conjunctival autograft for pterygium

BACKGROUND

A pterygium is a fleshy, wing-shaped growth from the conjunctiva, crossing over the limbus onto the cornea. Prevalence ranges widely around the world. Evidence suggests that ultraviolet light is a major contributor in the formation of pterygia. Pterygia impair vision, limit eye movements, and can cause eye irritation, foreign body sensation, and dryness. In some susceptible patients, the pterygium can grow over the entire corneal surface, blocking the visual axis.Surgery is the only effective treatment for pterygium, though recurrences are common. With simple excision techniques (that is, excising the pterygium and leaving bare sclera), the risk of recurrence has been reported to be upwards of 80%. Pterygium excision combined with a tissue graft has a lower risk of recurrence. In conjunctival autograft surgery, conjunctival tissue from another part of the person's eye along with limbal tissue is resected in one piece and used to cover the area from which the pterygium was excised. Another type of tissue graft surgery for pterygium is amniotic membrane graft, whereby a piece of donor amniotic membrane is fixed to the remaining limbus and bare sclera area after the pterygium has been excised.

OBJECTIVES

The objective of this review was to assess the safety and effectiveness of conjunctival autograft (with or without adjunctive therapy) compared with amniotic membrane graft (with or without adjunctive therapy) for pterygium. We also planned to determine whether use of MMC yielded better surgical results and to assess the direct and indirect comparative costs of these procedures.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (Issue 10, 2015), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2015), EMBASE (January 1980 to November 2015), PubMed (1948 to November 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to November 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (last searched 21 November 2014), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 23 November 2015.

SELECTION CRITERIA

We included in this review randomized controlled trials that had compared conjunctival autograft surgery (with or without adjunctive therapy) with amniotic membrane graft surgery (with or without adjunctive therapy) in people with primary or recurrent pterygium.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results and assessed full-text reports from among the potentially eligible trials. Two review authors independently extracted data from the included trials and assessed the trial characteristics and risk of bias. The primary outcome was the risk of recurrence of pterygium at 3 months and 6 months after surgery. We combined results from individual studies in meta-analyses using random-effects models. Risk of recurrence of pterygium was reported using risk ratios to compare conjunctival autograft with amniotic membrane transplant.

MAIN RESULTS

We identified 20 studies that had analyzed a total of 1947 eyes of 1866 participants (individual studies ranged from 8 to 346 participants who were randomized). The studies were conducted in eight different countries: one in Brazil, three in China, three in Cuba, one in Egypt, two in Iran, two in Thailand, seven in Turkey, and one in Venezuela. Overall risk of bias was unclear, as many studies did not provide information on randomization methods or masking to prevent performance and detection bias.The risk ratio for recurrence of pterygium using conjunctival autograft versus amniotic membrane transplant was 0.87 (95% confidence interval (CI) 0.43 to 1.77) and 0.53 (95% CI 0.33 to 0.85) at 3 months and 6 months, respectively. These estimates include participants with primary and recurrent pterygia. We performed a subgroup analysis to compare participants with primary pterygia with participants with recurrent pterygia. For participants with primary pterygia, the risk ratio was 0.92 (95% CI 0.37 to 2.30) and 0.58 (95% CI 0.27 to 1.27) at 3 months and 6 months, respectively. We were only able to estimate the recurrence of pterygia at 6 months for participants with recurrent pterygia, and the risk ratio comparing conjunctival autograft with amniotic membrane transplant was 0.45 (95% CI 0.21 to 0.99). One included study was a doctoral thesis and did not use allocation concealment. When this study was excluded in a sensitivity analysis, the risk ratio for pterygium recurrence at 6 months' follow-up was 0.43 (95% CI 0.30 to 0.62) for participants with primary and recurrent pterygium. One of the secondary outcomes, the proportion of participants with clinical improvement, was analyzed in only one study. This study reported clinical outcome as the risk of non-recurrence, which was seen in 93.8% of participants in the conjunctival limbal autograft group and 93.3% in the amniotic membrane transplant group at 3 months after surgery.We did not analyze data on the need for repeat surgery, vision-related quality of life, and direct and indirect costs of surgery due to an insufficient number of studies reporting these outcomes.Thirteen studies reported adverse events associated with conjunctival autograft surgery and amniotic membrane transplant surgery. Adverse events that occurred in more than one study were granuloma and pyogenic granuloma and increased intraocular pressure. None of the included studies reported that participants had developed induced astigmatism.

AUTHORS' CONCLUSIONS

In association with pterygium excision, conjunctival autograft is associated with a lower risk of recurrence at six months' after surgery than amniotic membrane transplant. Participants with recurrent pterygia in particular have a lower risk of recurrence when they receive conjunctival autograft surgery compared with amniotic membrane transplant. There are few studies comparing the two techniques with respect to visual acuity outcomes, and we identified no studies that reported on vision-related quality of life or direct or indirect costs. Comparison of these two procedures in such outcome measures bears further investigation. There were an insufficient number of studies that used adjunctive mitomycin C to estimate the effects on pterygium recurrence following conjunctival autograft or amniotic membrane transplant.

Assessment of Consistency in Assignment of Severe (Grade 3) Squamous Metaplasia to Human Bulbar Conjunctiva Impression Cytology Cell Samples

Nucleus-to-cytoplasm (N:C) characteristics of published images of human bulbar conjunctival cells designated as showing severe (grade 3) squamous metaplasia were retrospectively assessed. From publications over a 40-year period, measurements were made from images of cell and nucleus size (based on areas and dimensions) and four different calculations were made for nucleo-cytoplasmic (N:C) ratios. From 54 published images, the mean nucleus-to-cytoplasm area ratio (NU/CYT AREA ratio) was 0.145 +/- 0.077 (range 0.052 to 0.346), compared to two different reference set values of 0.069 +/- 0.017 and 0.080 +/- 0.021. Similarly, a nucleus-to-cytoplasm length ratio (as LNLONG) was 0.308 +/- 0.080 (range 0.191 to 0.475) compared to reference values of 0.226 +/- 0.032 and 0.236 +/- 0.034. Similar differences in reference values were obtained using two other N:C ratio calculations. A wide range of values was found for morphometric N:C indices from published images, especially those without a scale bar, indicating a high incidence of inconsistent grading assignments. Overall, only about 30% of the published images showed morphological features consistent with severe squamous metaplasia (i.e., with the rest neither enlarged nor showing substantially changed N:C ratios) with no substantial pictorial evidence indicating that cells from the human bulbar conjunctiva have pyknotic nuclei. Current evidence indicates that grade 3 squamous metaplasia cells should be substantially enlarged.

Collagen matrix implantation following pterygium excision: outcomes of a preliminary tested hypothesis

This study was conducted to evaluate the effect of collagen matrix implant on pterygium recurrence compared with a control group following pterygium removal surgery. Following informed consent, twenty eyes of 20 patients (females = 13, males = 7, aged 23-67 years) were randomly allocated into two equal groups. Pterygia of all patients were excised using the bare sclera technique; however, for patients in the intervention group a 1×2 mm collagen matrix graft (iGen™) was implanted subconjunctivally. Patients were followed up for recurrence and complications within six months. Results revealed that only two eyes in the control group and one eye in the intervention group developed recurrence (p=0.50); no dellen formation was observed. In conclusion, the use of biodegradable collagen matrix implants (iGen™) following pterygium excision seems to be associated with a lower risk of recurrence; however, the statistical difference between groups was not significant. Further studies with adequate sample size are recommended.