|Year : 2013 | Volume
| Issue : 2 | Page : 91-93
Is amniotic membrane transplantation, an adjuvant of choice following excision of primary Pterygium?
Assistant Professor/Specialist, ESIC MC and PGIMSR, Rajajinagar, Bangalore, Karnataka, India
|Date of Submission||29-Sep-2013|
|Date of Acceptance||13-Feb-2013|
|Date of Web Publication||20-May-2013|
No.13, Manuvana, Vijayanagar, Bangalore-560 040
Source of Support: None, Conflict of Interest: None
Though, Conjunctivo-limbal auto-graft is the most accepted adjuvant to prevent recurrence of pterygium, has its own limitations like difficulty to cover large defect and to preserve for future glaucoma surgeries, necessiating to find an alternative especially, in young patients. The outcomes between amniotic membrane transplantation (AMT) and conjunctivo-limbal auto graft transplantation (CLAT) as an adjuvant following excision of primary pterygia from Jan. 2010 to Dec.2010 were compared. Twenty four patients had AMT and 28 patients had CLAT after pterygium excision and followed for minimum of 12 months; evaluated in terms of recurrence or complications. We had 44% young (<40yrs) with 58% female. Epithelial healing occurred within a week. AMT cases showed 8% recurrence, nil in CLAT but, with 2 cases of pyogenic granuloma. We conclude that, AMT as an adjuvant would be a viable option reserving CLAT for those with recurrence or as a last resort especially, in younger patients.
|How to cite this article:|
Shashikala P. Is amniotic membrane transplantation, an adjuvant of choice following excision of primary Pterygium?. J Clin Ophthalmol Res 2013;1:91-3
|How to cite this URL:|
Shashikala P. Is amniotic membrane transplantation, an adjuvant of choice following excision of primary Pterygium?. J Clin Ophthalmol Res [serial online] 2013 [cited 2020 Dec 2];1:91-3. Available from: https://www.jcor.in/text.asp?2013/1/2/91/112177
The best-known ultra violet (UV) sunlight induced ocular surface disease pterygium, is a primary degenerative and hyper-plastic pathology of the conjunctiva that, affect visual acuity in different ways. With a thin ozone layer failing to block UV sunlight resulting in relatively high incidence of this entity, makes it an important public-health problem.  While the definitive management of a pterygium is surgical, the high recurrence rate is the most common complication and which is more difficult to tackle. Recent studies ,[ 2] have shown the role of limbal stem cell deficiency (LSCD) as a pathology which has led to the use of limbal auto graft as the most successful adjuvant. However, the difficulty in closing larger defects and the need to preserve conjunctiva for future glaucoma surgeries if needed are important limitations. Hence, there is a need to consider an adjuvant which can replace the auto graft with a minimal compromise, especially in young patients.
Aim of the study was to evaluate and compare the outcomes of primary pterygium excision with adjuvant between conjunctival-limbal auto transplantation (CLAT) and amniotic membrane transplantation (AMT). The primary outcome measure was the recurrence (1.5 mm re-growth within limbus) and the secondary outcome measures were rate of complications, epithelial healing and cosmetic appearance.
| Materials and Methods|| |
It was a prospective interventional comparative study on patients with primary pterygium between January 2010 and October 2011. Institutional ethics committee approval was obtained and consent was taken from the participants.
Patients were taken up for CLAT or AMT on alternate weeks. We noted a detailed history and ocular evaluation to include primary nasal or temporal pterygia and exclude cases having had double headed or recurrent pterygium, previous ocular surgery, glaucoma, ocular surface/lid abnormalities, adnexal infections and one eyed, eyes with any anterior or posterior segment pathology and also those with systemic conditions like diabetes mellitus or collagen vascular disease, pregnancy and inability to come for follow-up. Pterygia were graded as per Tan et al's system  as type 1 (atrophic), type 2 (minimal inflammation), and type 3 (moderate/severe inflammation or showing active fleshy growth).
All surgeries were performed by a single surgeon under subconjunctival anesthesia. The head of the pterygium was first separated at the limbus and dissected towards the central cornea with a pair of spring scissors. After excising the head and the body, tenon and subconjunctival fibrovascular tissue were separated from the overlying conjunctiva, undermined and excised. Bleeding vessels cauterized gently. The conjunctiva above and below the pterygium was trimmed to create a rectangular area of bare sclera. Residual fibrovascular tissue over the cornea was detached by gentle scraping with a no.15 surgical blade. The area of bare sclera was covered with either conjunctival limbal auto graft (CLAG) with appropriate limbal orientation or amniotic membrane graft (AMG) with basement membrane up, by suturing the graft through the episcleral tissue to the edge of the conjunctiva along the bare scleral border with 4 to 8 interrupted 10-0 nylon sutures and the eye was patched for a day.
Postoperatively, an antibiotic -steroid combination administered six times a day and lubricants eye drops ten times a day. Patients were examined on first few consecutive days until epithelial healing, first week to remove sutures, thereafter, tapering topical agents over three weeks. Patients followed on first, third, sixth and twelfth month. During follow-up, complications like epithelial defects, pyogenic granuloma, inclusion cysts, dellen formation and excessive photophobia were recorded along with recurrence rate and cosmetic appearance. To look at the cosmetic appearance at the available final follow-up, we followed Prabahasawat et al. system  and reported as 1- 4 grades.
| Results|| |
Fifty-two patients with primary pterygia consented and underwent surgical excision out of which 28 patients had CLAT and 24 patients had AMT. Age of the patients ranged from 24-65 years. Thirty of 52 (58%) patients were in 40-50 years in both category; however, 14 of 28 (50%) were below 40 years in CLAT category and in AMT category, 9 of 24 patients were below 40 years i.e., totally, 44% were below 40 years as shown in [Table 1]. Female preponderance (58%) seen in both categories. Majority was of type 2 and 3 and comparable in both categories as shown in [Table 2]; so as the average rate of epithelial healing [Figure 1]. Two cases each of pyogenic granuloma and graft edema were seen in CLAT category while none in AMT category as in [Table 3]. Recurrence was nil in CLAT while seen in 2 of 24 (8%) in AMT category. Cosmetic appearance were of grades 1 and 2 in CLAT category with no unacceptable recurrence, while in AMT category though majority had grades 1 and 2, 4% had grade 3 and 4% had grade 4 outcome, making to 8% un-acceptable recurrence as depicted in [Figure 2].
|Table 1: Age and prevalence of pterygium (CLATconjunctival limbal auto transplantation, AMT- amniotic|
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| Discussion|| |
Pterygium is characterized by excessive fibro vascular proliferation on the exposed ocular surface, and is thought to be caused by increased UV light exposure from climatic factors and aggravated by micro trauma and chronic inflammation from environmental factors. Despite the multi factorial pathogenesis, surgery is the mainstay of treatment. Pterygium excision is not a trivial procedure, as the recurrence rate may be as high as 69% especially in hot, dry and sunny atmosphere without an adjunctive therapy.  The common age at presentation is 40-50 years. Present study reported 58% in 40-50 years category however, 44% were below 40 years. So, a younger age tendency was evident among our patients. Male preponderance is seen in most studies; however female preponderance (58%) was seen in our study. The primary outcome measure was the recurrence seen in 2 of 24 (8%) in AMT cases and none in CLAT. This was comparable to that found in other studies like recurrence rate of 2.6% in CLAT and 10.9% in AMT found in Prabhasawat P et al. study,  3.8% and 5.4% respectively in CLAT and AMT category in David Hui-Kang Ma et al. study,  2.6% in CLAT and 3% in AMT category in Soloman A et al study.  Secondary outcome measures were rate of epithelial healing which was comparable in both CLAT and AMT cases. The cosmetic appearance was excellent in CLAT; AMT cases were comparable.
At present, CLAG have been a proved best adjunct as, in addition to the contact inhibition effect on residual abnormal tissue, it may also contain limbal stem cells which restores the limbal barrier, and hence, prevents recurrence.  However, It is believed that, it is the surgical trauma and post-operative inflammation which activate sub conjunctival fibroblast, vascular proliferation, and deposition of extracellular matrix proteins contributing to the recurrence of the lesion. 
Hence, AMG was thought of as a possible alternative to promote the proliferation and differentiation of residual normal limbal epithelial cells whereby it inhibits the fibro vascular in growth , through its anti-neo vascularization, anti-fibroblastic and anti-inflammatory effect. The added advantages are no pain, inflammation or risk in the donor site, reduction in surgical time by 5-10 min, easier to handle and suture (AMT is thicker and more elastic), larger sizes of graft available for larger primary or two headed pterygium, quicker patient recovery without going through the chemotic phase, save the donor site for glaucoma or other uses, especially in young patients.
| Conclusion|| |
Recurrence being the significant complication, most of which recur within a year and with a trend of younger generation presenting with pterygia, "AMT as an adjuvant" would be a viable option for primary pterygia reserving CLAT for those with recurrence or as a last resort. The limitations of the study are small sample size and limited period of follow-up.
| References|| |
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]