|Year : 2015 | Volume
| Issue : 2 | Page : 45-49
One-year results of the triple procedure for primary pterygia
Hisham A Saad1, Ahmed M Ghoneim2, Waleed A Allam MD 2
1 Ophthalmology Department, Faculty of Medicine, Tanta University; Ophthalmology Department, Magrabi Eye Hospital, Tanta, Egypt
2 Ophthalmology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
|Date of Submission||10-Jun-2015|
|Date of Acceptance||29-Jul-2015|
|Date of Web Publication||28-Oct-2015|
Waleed A Allam
Ophthalmology Department, Tanta University Eye Hospital, Tanta 31111
Source of Support: None, Conflict of Interest: None
The aim of this work was to study the effectiveness and potential complications of adjunctive intraoperative mitomycin-C (MMC) application combined with limbal-conjunctival autografting after primary pterygium excision.
Patients and methods
Fifty-seven eyes of 43 patients with primary pterygia were randomized to receive pterygium excision, followed by either a free conjunctival autograft (control group, n = 27) or an adjunctive intraoperative MMC 0.02% application for 2 min and limbal-conjunctival autograft (triple procedure group, n = 30). All patients were followed for 12 months.
After 1 year, the recurrence rate was 14.81 and 0% in the control and the triple procedure groups, respectively (P < 0.05). Most complications were transient and mild. The duration of surgery was significantly shorter in the control group (P < 0.01). The surgery did not significantly alter the corrected distance visual acuity or the average absolute astigmatism in either group.
Simple excision of pterygium combined with adjunctive intraoperative MMC 0.02% application for 2 min and limbal-conjunctival autografting is a safe and effective way of treating primary pterygia.
Keywords: limbal-conjunctival autograft, mitomycin-C, primary pterygia
|How to cite this article:|
Saad HA, Ghoneim AM, Allam WA. One-year results of the triple procedure for primary pterygia. Delta J Ophthalmol 2015;16:45-9
|How to cite this URL:|
Saad HA, Ghoneim AM, Allam WA. One-year results of the triple procedure for primary pterygia. Delta J Ophthalmol [serial online] 2015 [cited 2018 Apr 23];16:45-9. Available from: http://www.djo.eg.net/text.asp?2015/16/2/45/168526
| Introduction|| |
Recently, better understanding of the pathogenesis of pterygium and whether this lesion is a degenerative, neoplastic, or representative of focal limbal failure helped to introduce a variety of surgical procedures that were described to reduce the risk of recurrence after surgical excision of pterygia ,,,,,,, .
Corneal epithelium is normally regenerated from stem cells situated at the limbus that act as a transition zone or barrier between the corneal and the conjunctival epithelium. Disruption of this barrier secondary to noxious stimuli results in conjuctivalization of the corneal surface, with extensive cellular proliferation, inflammation, connective tissue remodeling, and angiogenesis  .
Mitomycin-C (MMC) is an antimetabolite that alkylates and cross-links DNA, resulting in inhibition of cellular proliferation. It had been proven to be safe and beneficial in glaucoma surgery. Intraoperative MMC has been reported to decrease the recurrence rate after pterygium excision to 3.3-43.7% ,,,,,,,, .
Different ocular surface reconstruction modalities were described to reduce the recurrence rate of pterygium compared with the bare scleral technique (up to 80% recurrence)  . Examples for these surgical modalities include amniotic membrane transplant (3.8-37.5% recurrence), sliding conjunctival flap (1-5% recurrence), conjunctival autograft (2.6-39% recurrence), and limbal-conjunctival autograft (0-14.6% recurrence) ,,, .
With the varying published results of pterygium recurrence after excision and using different surgical techniques and adjunctive treatments, the authors decided to combine pterygium excision, intraoperative use of MMC, and conjunctival-limbal autografting in one procedure and describe the outcome of this prospective case series with a follow-up period of 1 year in comparison with conjunctival autografting alone.
| Patients and methods|| |
This prospective, interventional, comparative case series was carried out at Tanta University Eye Hospital in Tanta, Egypt during the period from July 2013 to February 2014, after IRB approval, with a postoperative follow up period of 12 months.
After informed consent was obtained, 43 consecutive patients with primary pterygia, 57 eyes, were enrolled in this study. Demographic data, and previous medical and surgical treatments were recorded. All patients underwent a complete ophthalmologic examination.
Visual acuity was averaged using the logarithm of minimum angle of resolution (logMAR). Astigmatism was recorded as the spectacle correction needed for corrected distance visual acuity and only the amount of the astigmatism was averaged. The size of the pterygium was measured, and its location and type were recorded. Patients with severe dry eyes, ocular surface disease, and systemic collagen vascular disorders were excluded from the study.
The enrolled eyes were randomized to receive either a free conjunctival autograft (control group, n = 27) or an intraoperative adjunctive MMC 0.02% and limbal-conjunctival autograft (triple procedure group, n = 30). All eyes were operated on by the same surgeon.
The surgery was performed in the operating room under local anesthesia. After prepping and draping of the eye, topical benoxinate hydrochloride 0.4% (Benox, EIPICO, Cairo, Egypt) was applied. A speculum was placed between the eyelids. A sharp crescent knife was used to make an epithelial scratch mark 0.5-1.0 mm in front of the cap of the pterygium in the clear cornea. A gentian violet marking pen was then used to outline the body of the pterygium and the area to be excised, and then 0.5-1.0 ml mepivacaine HCl 36 mg/ml with levonordefrin HCl 0.108 mg/1.8 ml (Mepecaine-L, Alexandria, Egypt) mixture was injected into the subconjunctival space beneath the body of the pterygium. A merocel was used to distribute the local anesthetic into the subconjunctival space. Two full-thickness conjunctival incisions were performed perpendicular to the limbus above and below the body of the pterygium [Figure 1]a and then connected with a circumferential incision 5 mm from the limbus along the preplaced gentian violet marks [Figure 1]b. The entire mass of the pterygium body and the conjunctiva were bluntly dissected toward the limbus. Cauterization of bleeding vessels was performed as necessary. The head and neck of the pterygium were peeled off the corneal bed using a crescent knife till the epithelial scratch mark [Figure 1]d. A diamond-dusted surgical burr (Alger Brush II, Alger, Lago Vista, TX, USA) was then used to smoothen the corneal bed as necessary [Figure 1]e. No extended excision of the Tenon's tissue under the remaining conjunctiva was performed.
In the control group, an autologous conjunctival graft was obtained from the upper bulbar conjunctiva with as less Tenon's tissue on the graft as possible and was sized 30% larger than the pterygium bed. The graft was fixed in place first by four cardinal 10/0 nylon sutures, and then additional sutures were used to secure the rest of the graft as necessary, followed by application of a bandage contact lens.
In the triple-procedure group, a merocel soaked with MMC 0.02% was applied on the scleral bed of the excised pterygium for 2 min [Figure 1]f, then it was removed and the bed was rinsed with normal saline solution. A limbal conjunctival autograft was harvested from the upper temporal bulbar conjunctiva of the same eye. First, gentian violet marking pen was used to outline the edge of the graft and was sized 0.5 mm larger in width than the bed, and then Wescott scissors were used to dissect the graft toward the limbus with as minimal Tenon's tissue as possible [Figure 2]a. Once the dissection reached the limbus, a shallow circumferential incision was performed and superficial lamellar dissection was carried on for 1 mm into the clear cornea using a crescent knife [Figure 2]b. Then, the graft was harvested with the scissors [Figure 2]c and transferred to the recipient bed, maintaining the limbal orientation [Figure 2]d. The graft was secured in place with 10/0 nylon sutures [Figure 2]e, followed by application of a bandage contact lens [Figure 2]f.
Postoperatively, all eyes were patched for 2 days. All patients were administered combined tobramycin and dexamethasone eye drops (Tobradex; Alcon), and were instructed to use them four times daily together with artificial tears (Refresh liquigel; Allergan). Only artificial tears were used in refills for at least 3 months postoperatively. Bandage contact lenses were removed 1 week after surgery.
The patients were examined 1, 3, 6, and 12 months after surgery. A recurrence was defined as a lesion with more than 1 mm of fibrovascular regrowth over the cornea at the site of surgery.
| Results|| |
The average age of the patients was 47.05 ± 9.65 years (range 31-60 years) in the control group and 49.5 ± 10.48 years (range 33-65 years) in the triple-procedure group. There were 40% women and 60% men in the control group and 39.5% women and 60.5% men in the triple-procedure group. No significant differences were recorded between the treatment groups in age and sex of the participants.
The pterygium area measured 6.5 ± 4.0 mm 2 (range 4-26.0 mm 2 ) in the control group and 6.9 ± 4.5 mm 2 (range 4-28.0 mm 2 ) in the triple-procedure group, with no statistically significant differences between the two groups.
The surgery did not significantly alter the corrected distance visual acuity or the average absolute astigmatism in either group [Table 1].
The duration of surgery was significantly shorter in the control group, 40 ± 7 min (range 26-58 min), compared with the triple-procedure group: 50 ± 5 min (range 30-60 min) (P < 0.01).
Most complications were transient and mild [Table 2]. Suture granuloma was recorded in two cases in the control group and in one case in the triple-procedure group. These granulomas were treated by removal of the stitch and administration of combined antibiotic and corticosteroid eye drops. Graft retraction and wound gapping as a result of breaking of the nasal sutures occurred in five cases: three in the control group and two in the triple procedure group. These cases were treated with frequent application of artificial tears eye drops and gels till secondary healing of the scleral bed. Delayed epithelialization of the cornea (more than 2 weeks) was observed in 7.41% (n = 2) of the patients in the control group, but in none of the patients in the triple-procedure group. Elevated intraocular pressure caused by the topical steroid treatment was managed by eye drops, which could be discontinued in all cases at the 1-month visit. None of the patients developed persistent elevation in the intraocular pressure. After 1 year, the recurrence rate was 14.81 and 0% in the control and in the triple-procedure groups, respectively (P < 0.05) [Figure 3].
| Discussion|| |
Prevention of pterygium recurrence after surgical excision has been a challenge in the past. The modern techniques described in the literature for the treatment of pterygium focus on two major goals:
However, a direct comparison of the efficacy of these techniques is difficult because of various factors such as the follow-up period and the definition of recurrence, which varies among the studies  .
- Anatomical reconstruction to cover the bare scleral area after excision of the pterygium, such as conjunctival autograft, limbal-conjunctival autograft, sliding conjunctival flap, or amniotic membrane transplantation and
- Suppression of regrowth of pterygial tissue by either radiotherapy in the form of local β-irradiation or local chemotherapy by MMC application.
The aim of this study was to establish a pterygium surgery that is safe and easy to perform in an attempt to reduce the pterygium recurrence rate. We chose to perform a triple procedure that combined pterygium excision and adjunctive intraoperative MMC 0.02% with limbal conjunctival autografting and compare the results with those of the free conjunctival autografting technique.
MMC gained popularity as a postoperative adjunctive therapy to pterygium excision , . However, reports on serious side effects such as delayed epithelial healing, scleral and/or corneal melting, infective keratitis, endophthalmitis, and cataract formation were concerns , .
Unlike the postoperative MMC therapy, intraoperative application of MMC allows the surgeon to accurately control the exact localization, concentration, and duration of exposure of application , . Wong and Law  in 1999 found that the recurrence rate was significantly lower in the MMC/amniotic membrane group (7%) than in the group treated with amniotic membrane alone (26%).
However, if we take into consideration that the main objectives of pterygium surgery are to reconstruct the anatomical bed and restore the limbal barrier, then the use of MMC alone or in combination with amniotic membrane transplant, after excision of the pterygium, is not enough to completely prevent recurrence.
In addition, it is not clear whether or not the action of MMC is restricted to fibroblasts, which means that it could affect the viability of other cells such as limbal stem cells, which are responsible for restoration of a functional limbal barrier in a disease already expressing a gradual loss of such cells  .
Conjunctival autografting was described as a treatment for pterygium by Kenyon and colleagues in 1985. They proposed that the placement of healthy conjunctiva between the pterygium tissue and cornea functions as a barrier that prevents the regrowth of pterygium tissue onto the cornea. However, they reported a 5.3% recurrence rate after 57 procedures (41 recurrent pterygia and 16 primary pterygia) after a mean follow-up period of 24 months  .
Lewallen  , in 1989, reported a 40% recurrence rate with the bare sclera technique versus 7% with conjunctival autografting. Another retrospective review of 93 pterygia treated by conjunctival autografting by Allan et al.  in 1993 in Australia found a 6.5% recurrence rate with a minimum of 6 months of follow-up. Another retrospective survey of 71 patients with primary pterygium by Figueiredo et al.  in 1997 showed a 1-year recurrence rate of 16% in patients treated with conjunctival autografting compared with 40% in those treated with simple excision.
Causes of variations in the reported recurrence rates could be attributed to differences in study methodology, patients' characteristics, nature of pterygium, definition of recurrence, and duration of follow-up  .
All recurrences after pterygium surgery appeared within a year in the control group. Hirst et al.  showed that there is a 50% chance for a recurrence after pterygium surgery to occur within 4 months and a 97% chance within 1 year. In another article on recurrence time by Avisar et al.  , it was shown that a 1-year follow-up period is optimal, which is also in agreement with the present study.
With the currently described technique of the triple procedure, the authors could achieve excellent results, that is, a highly acceptable cosmetic appearance with no recurrence. However, our described technique of surgery is extensive and needs time to master. The difficulties are in harvesting the limbal-conjunctival autograft and its proper placement on the recipient bed.
| Conclusion|| |
The combined procedures of pterygium excision, intraoperative MMC 0.02%, and autologous limbal conjunctival autografting appeared to be significantly more successful in terms of the recurrence rate than conjunctival autografting alone. Suppression of cellular proliferation at the bed of the pterygium with MMC, together with restoration of the barrier function at the limbus through limbal-conjunctival autografting, proved to be an ideal combination that successfully prevented recurrence during the 12-month follow-up period. We strongly recommend this technique of surgery in the management of primary pterygia.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]