Effects of mitomycin C on corneal endothelial cell counts in pterygium surgery: role of application location

Evaluating the Efficacy and Safety of Different Pterygium Surgeries: A Review of the Literature

The search for the "gold standard" in the surgical treatment of pterygium has been ongoing for over two decades. Despite the development of various surgical techniques, recurrence rates range from 6.7% to 88% depending on the method used. This review discusses the latest and most commonly used methods for the surgical removal of pterygium, primarily focusing on efficacy and safety. Moreover, this review includes articles that either evaluated or compared surgical methods and clinical trials for primary and recurrent pterygium. Limited data are available on combined methods as well as on the efficacy of adjuvant treatment. The use of adjuvant intraoperative mitomycin C (MMC) and conjunctival autografting (CAU) are the two most highly recommended options, as they have the lowest rates of postoperative recurrence.

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.

Efficacy and Safety of a Large Conjunctival Autograft for Recurrent Pterygium

PURPOSE

To evaluate the efficacy and safety of pterygium excision using a large conjunctival autograft for the treatment of recurrent pterygium.

METHODS

The medical records of 120 patients (126 eyes) with recurrent pterygium were reviewed. For each affected eye, pterygium excision with a large conjunctival autograft was performed. The graft was harvested from the superior bulbar area and measured more than 8 × 10 mm in size. Only patients who completed at least six months of follow-up were included. Postoperative clinical outcomes, recurrence rate, and complications were analyzed. Patients with any evidence of recurrence after surgery received a subconjunctival bevacizumab injection.

RESULTS

The average patient age was 56.5 ± 10.2 years, and 45 out of 120 patients were male. The mean study follow-up period was 17.7 ± 17.6 months. Most patients were satisfied with the cosmetic outcome. Postoperative visual acuity improved from 0.69 to 0.75 (p < 0.05). Postoperative refractive astigmatism and corneal astigmatism decreased by 0.55 and 2.73 diopters, respectively (p < 0.05). The postoperative recurrence rate was 4.0%, and the average recurrence period was 7.4 ± 0.6 weeks. A subconjunctival injection of 5 mg bevacizumab was performed in cases of recurrence; no progression of the pterygium was observed following the injection. Postoperative complications included 2 cases of conjunctival graft edema in 2 eyes, 5 donor site scars in 5 eyes, 13 pyogenic granulomas in 13 eyes, and a conjunctival epithelial inclusion cyst in 7 eyes.

CONCLUSIONS

Pterygium excision with a large conjunctival autograft for the treatment of recurrent pterygium produced an excellent cosmetic outcome, a low recurrence rate, and minimal complications. A subconjunctival bevacizumab injection given in cases of recurrence following surgery might be effective in preventing progression of the pterygium.

Comparison of intra-operative 0.02% mitomycin C and sutureless limbal conjunctival autograft fixation in pterygium surgery: five-year follow-up

PURPOSE

To compare efficacy and safety between fibrin sealant assisted limbal conjunctival autograft fixation and intra-operative MMC in pterygium surgery.

METHODS

Prospective, comparative, interventional case series. Forty eyes of 40 patients with nasal primary pterygium, 18 male and 22 female, were enrolled. The patients were assigned to two groups, and each contained nine male and 11 female based on the pterygium area encroaching onto the cornea. In one group, the conjunctival autograft was attached to the sclera with fibrin sealant, and in the other group, 0.02% MMC was applied after the pterygium was removed. All the patients were followed up postoperatively on days 1, 3, 7 and 14 then at months 1, 2, 6, 12 and 60. The main outcome measures included operating time, postoperative discomfort, cornea endothelial damage, recurrence rate and complications.

RESULTS

The average operating time was significantly shorter (p = 0.044) in the fibrin sealant group, and fewer postoperative symptom complaints were received as well. On postoperative month 1, no significant differences in the mean endothelial cell count, mean CV and mean 6A% were observed between these two groups. By the end of 5-year follow-up, the recurrence rate was 0% in the fibrin sealant group and 20% in the MMC group (p = 0.106), and there were no severe visual acuity threatening complications in either group.

CONCLUSION

There were no severe complications after long-term follow-up if intra-operative MMC was strictly and carefully used. Overall, this sutureless method is more effective than traditional MMC.

Conjunctival Short-term Evolution after Pterygium Excision

PURPOSE

To analyze conjunctival cytological features 1 month after pterygium excision using limbo-conjunctival autograft (LCA) with and without intraoperative mitomycin C and to assess tissue short-term evolution in both situations.

METHODS

Fifty-nine primary nasal pterygia from 59 patients were excised with LCA. Twenty-nine were treated with intraoperative mitomycin C 0.02% (MMC+) and 30 were treated without it (MMC-). Impression cytology was performed in nasal and temporal conjunctiva before and 1 month after the excision. Goblet cell density (GCD) and nucleus-to-cytoplasm nongoblet epithelial cell ratio were quantified.

RESULTS

Surgical strategy comparisons (intergroup comparisons): All the preoperative data were, in mean, within the reference range, except for a slight goblet cell hyperplasia in the area of the lesion in MMC+ but no significant differences were found between the groups (p = 0.079 for GCD and p = 0.245 for nucleus-to-cytoplasm ratio; analysis of variance). Clinically relevant differences after surgery were only shown in nasal GCD that was significantly lower in MMC+ than in MMC- (p = 0.000; analysis of variance), with the mean value in MMC+ slightly below normal values whereas that in MMC- remained normal. Tissue evolution (intragroup comparisons): No clinically relevant changes were found in MMC-. Data from MMC+ displayed no changes 1 month after surgery, except for nasal GCD that showed a significant reduction (p = 0.000; paired t test). Nevertheless, this GCD decrease was more modest than that previously described using mitomycin C without autograft, because in the present study, nasal GCD was not lower but similar to postoperative temporal data of the same eye (p = 0.164; paired t test).

CONCLUSIONS

Limbo-conjunctival autograft is a good technique for conjunctiva early recovery. When mitomycin C was added, the GCD reduction was lower than described using other surgical techniques. Mitomycin C, in optimal concentration and exposure, associated with LCA could be a good clinical option to minimize pterygium recurrence.

Threshold to predict astigmatism reduction after pterygium excision

PURPOSE

To compare corneal astigmatism after pterygium excision, using limbal-conjunctival autograft (LCA) with and without mitomycin C (MMC) and to establish a threshold for postoperative astigmatism reduction.

METHODS

Sixty-eight eyes with primary pterygium were consecutively sampled and assigned to LCA with MMC (MMC+) or LCA without MMC (MMC-). Corneal lesion length, corneal lesion area, preoperative corneal astigmatism (PRCA), and postoperative corneal astigmatism (POCA) at 1, 3, and 6 months were assessed.

RESULTS

Thirty-six men and 24 women (60 eyes), aged between 24 and 65 years (mean ± SD, 41 ± 8.2 years), completed the study. Thirty-one eyes were included in the MMC+ group and 29 were in the MMC- group. Both groups showed astigmatism reduction (p < 0.05; paired, two-tailed t test) 1 month after the surgery and remained stable. No differences were found between groups in corneal lesion length, corneal lesion area, or astigmatism results at the four time points (p > 0.05, independent t test). Preoperative corneal astigmatism showed a significant correlation with POCA at 6 months (r = 0.529; p < 0.01). According to receiver operating characteristic curve analysis, the better threshold for astigmatism reduction with the surgery was 1.05 diopters of PRCA, with 82.5% sensitivity and 80.5% specificity.

CONCLUSIONS

Both surgical procedures could have similar astigmatism results. Pterygium patients with more than 1.05 diopters of PRCA could reduce it after the surgery. Direct relationship between PRCA and POCA revealed that postoperative astigmatism reduction was partial. Therefore, for minimizing final astigmatism, preoperative values should be slightly above the threshold.

Topical chemotherapy for ocular surface squamous neoplasia

PURPOSE OF REVIEW

Ocular surface squamous neoplasia (OSSN) is an umbrella term for a spectrum of epithelial dysplasias of the cornea, conjunctiva, and limbus. Treatment for OSSN has historically been surgery, but nonsurgical interventions have been increasingly adopted. Advantages of medical treatments include the ability to treat the entire ocular surface and prevention of surgical complications.

RECENT FINDINGS

The primary medical treatments for OSSN include mitomycin C, 5-fluorouracil, and interferon α2b. Mitomycin C has been shown in studies to be highly effective but has short-term and long-term side-effects that may be intolerable. 5-Fluorouracil and interferon α2b have been found to be similar in efficacy to mitomycin, with interferon being extremely well tolerated in the majority of patients. Most recently, other chemotherapeutic agents have been tried for OSSN including antivascular endothelial growth factor agents and vitamin A. The data regarding these latter treatment strategies are still limited.

SUMMARY

An understanding of the recent literature, with respect to the efficacy, advantages, and disadvantages of the various therapies for OSSN will allow us to tailor treatment to each patient.

Ten-year results of a randomized controlled trial comparing 0.02% mitomycin C and limbal conjunctival autograft in pterygium surgery

OBJECTIVE

To compare the long-term outcome of pterygium surgery and the long-term effect on endothelial counts after mitomycin C (MMC) or limbal conjunctival autograft (LCAU) in pterygium surgery.

DESIGN

We performed a 10-year follow-up study of a randomized controlled trial.

PARTICIPANTS

A total of 115 eyes of 114 patients with primary pterygium were treated with intraoperative MMC (n = 63) or LCAU transplants (n = 52). A total of 76 patients completed the current 10-year long-term follow-up (47 in the MMC group, 29 in the LCAU group).

METHODS

This is a follow-up study of a randomized controlled trial of a cohort of 114 patients in 2 groups that was performed at the Prince of Wales Hospital 10 years ago: group 1, intraoperative 0.02% MMC for 5 minutes; group 2, LCAU. Consecutive patients enrolled in the original study (recruitment began in February 2001) were invited back for a detailed clinical examination to document the long-term outcome of both surgical groups.

MAIN OUTCOME MEASURES

The main outcome measures included the recurrence rate, residual conjunctival bed status, complications, and corneal endothelial cell density (ECD) differences.

RESULTS

A total of 115 eyes of 114 patients were enrolled and randomized in our previous study. For the current study, 76 of the 114 patients (47 in the MMC group, 29 in the LCAU group) were contacted, whereas 18 patients were lost to follow-up and 20 patients had died. The mean follow-up period was 138 ± 2 months in the MMC group and 137 ± 2 months in the LCAU group. Twelve of 47 patients (25.5%) in the original MMC group and 2 of 29 patients (6.9%) in the LCAU group had recurrent pterygium (P = 0.021). The mean ECD was 2,39 2 ± 342 cells/mm(2) in the MMC group and 2,390 ± 388 cells/mm(2) in the LCAU group (P = 0.978). There was no significant difference in the ECD between the operated eyes and the fellow eyes in both groups (P = 0.926 MMC, P = 0.468 LCAU). No other significant ocular complications were observed in either group at the 10-year postoperative follow-up.

CONCLUSIONS

Limbal conjunctival autograft was more effective than intraoperative MMC in minimizing pterygium recurrence at the 10-year follow-up. Treatment with intraoperative MMC was not associated with long-term corneal endothelial cell loss.

Diamond burr superficial keratectomy with mitomycin C for corneal scarring and high corneal astigmatism after pterygium excision

Background

The purpose of this paper is to report the successful treatment of corneal scarring and high corneal astigmatism secondary to previous pterygium surgery with diamond burr superficial keratectomy using mitomycin C.

Methods

Four patients with corneal scarring and high corneal astigmatism related to previous pterygium surgery underwent diamond burr superficial keratectomy with application of mitomycin C. Anterior segment photography and corneal topographic analysis were obtained preoperatively and postoperatively in all patients.

Results

Six months after surgery, corneal astigmatism and corneal aberrations were reduced in all patients. A clear cornea was achieved in all cases. No complications were noted during the follow-up period.

Conclusion

Diamond burr superficial keratectomy with application of mitomycin C is a potentially effective and simple procedure for treating patients with corneal scarring and high corneal astigmatism secondary to previous pterygium surgery.