Reducing Postoperative Pterygium Recurrence: Comparison of Free Conjunctival Auto-Graft and Conjunctival Rotation Flap Techniques

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1 ORIGINAL ARTICLE Reducing Postoperative Pterygium Recurrence: Comparison of Free Conjunctival Auto-Graft and Conjunctival Rotation Flap Techniques Waseem Akhter, Ali Tayyab, Ayisha Kausar and Amena Masrur ABSTRACT Objective: To compare the recurrence of pterygium between free conjunctival auto-graft and conjunctival rotation flap following simple surgical excision of pterygium. Study Design: Quasi-experimental study. Place and Duration of Study: Shifa Foundation Community Health Clinic, Shifa College of Medicine, Islamabad, from January to November Methodology: Fifty seven cases aged above 18 years, with a pterygium corneal encroachment of 2 mm which was responsible for visual disability or was cosmetically undesirable were recruited for the study and randomly assigned to conjunctival auto-graft group and conjunctival rotation flap group. Cases with a history of glaucoma or glaucoma suspect, prior pterygium surgery, pterygium with concurrent ocular surface and lid disease, conjunctival inflammation and scarring, pseudo-pterygium or collagen vascular disease were excluded. After simple pterygium excision conjunctival auto-graft group (n=26) cases received a free conjunctival flap was transplanted, while conjunctival rotation flap group (n=31) cases received a conjunctival rotation flap. All cases were followed-up for 6 months after surgery for recurrence and complications. Frequency distribution and significance of association of recurrence using Fisher s exact test and Mann- Whitney U-test was carried out using Statistical Package for Social Sciences (SPSS) version 20. Results: The median (and inter-quartile range) age and surgery duration in conjunctival auto-graft group and conjunctival rotation flap group were 60 ( ) and 57 ( ) years, ( ) and ( ) minutes respectively. Recurrence was seen in 2 (7.96%) and 3 (9.76%) cases in auto-graft and rotation flap groups respectively. No significant difference was seen in postoperative complications between the two groups (p=0.60). Conclusion: The surgical time for conjunctival rotation flap procedure is less as compared to free auto-graft, while their recurrence and complications are comparable. Key Words: Pterygium. Simple excision. Recurrence. Conjunctival transplant. INTRODUCTION A pterygium is a triangular wing-shaped, fibro-vascular neoformation of abnormal conjunctiva onto the cornea, 1 with consequential cosmetic and visual annoyance for the patients. The pathogenesis of this neoformation remains largely unknown, however, recent investigations show similarities between genesis of pterygium and tumor formation. 2 Tropical residence and ultraviolet radiation exposure have been implicated as risk factors for formation of pterygium. 3,4 The prevalence of pterygium is reported to be as high as 33.00%, 5 while in South Asia it is 9.50%. 6 Simple surgical excision, the 'bare sclera technique', is an easy and common procedure used to manage pterygium. However, this procedure is associated with a Department of Ophthalmology, Shifa College of Medicine, Islamabad. Correspondence: Dr. Ali Tayyab, House No. 59-A, Street 16, F-11/2, Islamabad. ali.tayyab@gmail.com Received: March 24, 2014; Accepted: June 06, recurrence rate as high as 80%. 7 Application of Mitomycin C (MMC), beta-radiation, amniotic membrane and conjunctival transplant have been used in conjunction with simple surgical excision to reduce recurrence, with application of MMC alone or in combination with conjunctival transplant producing the best results. 8,9 However, application of MCC is associated with an array of side effects ranging from hyperemia, allergic reactions to corneal and scleral thinning, corneal perforation, cataracts and glaucoma. 10,11 Conjunctival tissue, either as rotation flap or free autograft has been used in conjunction with simple surgical excision to reduce surgical recurrence and avoid the side effects associated with the use of MMC. 12 Of the two transplant procedures, free conjunctival auto-graft procedure has lower reported recurrence and complication rates but requires training by qualified surgeons and has a longer surgical time. 13 Conjunctival rotation flap surgery is comparatively simple procedure to master and surgical time is also relatively short. 14 These procedures have not been widely compared locally for reducing recurrence, surgical times or postoperative complications. 740 Journal of the College of Physicians and Surgeons Pakistan 2014, Vol. 24 (10):

2 Reducing postoperative pterygium recurrence The objective of this study was to compare recurrence, surgical times and complications between conjunctival rotation flap and conjunctival free auto-graft procedures following simple pterygium excision. METHODOLOGY Approval for this quasi-experimental study was taken from the institutional review board. The study was conducted at Shifa College of Medicine, Islamabad between January and November A total of 57 eyes of 57 cases aged > 18 years and a pterygium that had a corneal encroachment of 2 mm, which was responsible for visual disability and/ or cosmetically undesirable for the patients were included in the study. Visual disability was defined as presence of pterygium and visual acuity of < 6/6 in absence of comorbid condition. If the pterygium was a source of annoyance or physical discomfort it was classified as cosmetically undesirable. Cases of glaucoma, glaucoma suspect, ocular hypertension, those who have had prior pterygium surgery, pterygium with concurrent ocular surface and lid disease (belpharitis, dry eyes, ectropion, entropion, chronic conjunctivitis), conjunctival inflammation and scarring, pseudo-pterygium or collagen vascular disease were excluded. A full disclosure of the study was made and informed consent taken. Explanation regarding the procedure, outcomes and potential complications were provided and all queries were answered to satisfaction. Visual acuity, automated keratometery, Slit-lamp biomicroscopic examination of the ocular adnexa, anterior and posterior segments of the eye was performed and intraocular pressure measured by applanation tonometer. The corneal encroachment of the pterygium was measured using a slit-lamp biomicroscope by a single observer to eliminate interobserver measurement bias. A small pterygium was defined as one with a corneal encroachment of 3 mm while a large pterygium was defined as one with a corneal encroachment of 4 mm. The cases were divided in two groups using computer generated random number sequences. The free conjunctival auto-graft group (CAG, n = 26), underwent simple pterygium excision followed by a free conjunctival auto-graft. The Conjunctival Rotation Flap Group (CRFG, n = 31), underwent pterygium excision followed by a conjunctival rotation flap. All procedures were performed by a single surgeon, blind to the study, with experience in pterygium surgery and conjunctival transplant procedures. Surgical time was measured from the start of the identification of pterygium to the application of antiseptic dressing. The preparation of the eye and procedure for pterygium excision was similar for both groups and is described as follows: Application of 10% povidone-iodine and opposite eye dressing ensured a sterile surgical field. The pterygium was identified, undermined in its entirety, clamped with curved artery forceps and excised in a single piece. The bed of the pterygium was cleared and the bare scleral area measured with calipers. For free conjunctival auto-grafting procedure, the graft tissue was harvested from the superotemporal bulbar conjunctiva, approximately 1 mm larger than the area of the bared sclera. The flap was dissected, completely freed from the underlying Tenon's capsule and transposed over the surgical site, aligning the limbal end of graft with the limbal end of the scleral bed. The graft was secured with the surrounding conjunctiva tissue and Tenon's capsule using 10/0 monofilament nylon suture. For conjunctival rotational flap procedure, the flap was created from the superior bulbar conjunctiva, rotated to the site of the scleral bed aligning the limbal end of the flap with the limbal end of the bared scleral bed and secured with 10/0 monofilament nylon suture to the surrounding conjunctiva and Tenon s capsule. The eye was closed with an anti-septic dressing after application of a 0.1% Dexamethasone with 0.3% Tobramycin eye ointment. A steroid and antibiotic combination (0.1% Dexamethasone and 0.3% Tobramycin) eye drop was prescribed to all patients in a 4 times/day dose for 4 weeks on discharge. Patients were examined on the first postoperative day then at one, three and six months after surgery for recurrence and complications. Recurrence of pterygium was defined as encroachment of the cornea by one millimeter or more by the growing conjunctival tissue from the surgical site within 6 months after surgery. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 20. Mann- Whitney U-analysis, with median and interquartile range, was performed to determine statistically significant differences in age and surgical times between the two groups. Fisher s exact test was performed to determine statistically significant differences in the gender of the population, recurrence of pterygium and surgical complications between the two groups. A p-value of < 0.05 was taken to be significant in all analysis. RESULTS Pterygium characteristics and demographics of the cases in the two groups are shown in Table I while Table II shows incidence of recurrence after surgery, surgical times and complications observed. A total of 57 eyes of 57 cases (33 males, 24 females) were recruited in the study. The CAG, (n=26) included 15 (57.69%) males and 11 (42.31%) females, while CRG (n=31) comprised of 18 (58.06%) male and 13 (41.94%) Journal of the College of Physicians and Surgeons Pakistan 2014, Vol. 24 (10):

3 Waseem Akhter, Ali Tayyab, Ayisha Kausar and Amena Masrur Table I: Pterygium characteristics and demographics. Characteristic Conjunctival auto-graft group (n=26) Conjunctival rotation flap group (n=31) Gender Males 15 (57.69%) 18 (58.06%) Females 11 (42.31%) 13 (41.94%) Age in years 60 ( ) 57 (45-60) Eye Right eye 9 (34.60%) 11 (35.5%) Left eye 17 (65.40%) 20 (64.50%) Criteria for Surgery Visual 17 (65.40%) 15 (48.40%) Cosmetic 9 (34.60%) 16 (51.60%) Corneal encroachment in mm 3.00 ( ) 3.00 ( ) Table II: Surgical times, recurrence and postoperative complications seen after pterygium surgery. Conjunctival auto-graft group Conjunctival rotation flap group p-value Surgical time in minutes ( ) ( ) < Recurrence 2 (7.96%) 3 (9.67%) 0.58 Males 2 (100%) 2 (66.67%) Females 0 (0%) 1 (33.33%) Pre-operative size of pterygium size 0.60 in cases of recurrence Large 2 (100%) 2 (66.67%) Small 0 1 (33.33%) Postoperative complications 3 (11.53%) 4 (14.81%) 0.60 Complications observed Edema 2 (66.67%) 3 (75%) Granuloma 1 (33.33%) 1 (25%) female cases. Fisher s exact analysis showed this difference in the gender composition of the two groups to be statistically insignificant (p=0.59). The median and inter-quartile range (IQR) of age in CAG and CRG were 60 ( ) and 57 ( ) years respectively (Table I). Mann-Whitney U-analysis shows this difference in age composition of the two groups to be statistically insignificant (p =0.14). The median (IQR) corneal encroachment in CAG was 3.00 ( ) mm while in CRG it was 3.00 ( ) mm (Table I). Mann-Whitney U-analysis shows this difference to be statistically insignificant (p=0.33). The pterygium was responsible for visual disability in 17 (65.40%) and 15 (48.40%) cases in CAG and CRG groups respectively whereas it was cosmetically undesirable in 9 (34.60%) and 16 (51.60%) cases in CAG and CRG groups respectively (Table I). The median (and IQR) surgery time in CAG was ( ) minutes; while in CRG the time was ( ) minutes (Table II). This difference was statistically significant (p < 0.001). Recurrence was seen in 2 (7.96%) cases in CAG and in 3 (9.67%) cases in CRG (Table II). This difference was not statistically significant (p = 0.58). Postoperative complications was seen in 3 (11.53%) cases in CAG and 4 (14.81%) in CRG, a difference that is statistically insignificant (p=0.60). DISCUSSION Recurrence of pterygium after surgery is a source of annoyance for the patient as well as for the surgeon necessitating another surgery. Though research into reducing the recurrence has shown promise, 8,9,12 finding an ideal procedure, that has no recurrence, has remained elusive. Conjunctival transplant, either as a free auto-graft or a rotational flap, is an effective procedure that reduces the recurrence of pterygium while avoiding the complications associated with the use of anti-fibrotic agents like Mitomycin C (MMC). Recurrence of pterygia usually occurs during the first 6 months after surgery. 15 Observation for longer postoperative duration shows no statistically significant difference in rate of recurrence when comparing the free conjunctival auto-graft and conjunctival rotation flap procedures. 14,16 The investigations into the two conjunctival transplant techniques show that both are equally effective in 742 Journal of the College of Physicians and Surgeons Pakistan 2014, Vol. 24 (10):

4 Reducing postoperative pterygium recurrence reducing recurrence (p=0.58), however, the rotational flap technique had a lower surgical time which was statistically significant (p < 0.001, Table II). There was no significant difference in the observed complications between the two groups (p=0.60) and we did not observe any serious complications (graft, conjunctival, corneal or scleral necrosis or perforation) in either of the two groups (Table II). Comparisons between free conjunctival auto-graft and conjunctival rotation flap procedures show similar results 14,16 in published literature with occasional exceptions. 8 Aslan, on a sample of 45 subjects, observed that the rate of recurrence of pterygium following rotation flap surgery and free auto-graft procedure (p=0.46) was comparable. 14 Kim observed statistically similar recurrence rates, 8.0% for auto-graft group versus 8.6% for rotational flap group, for a sample size that is comparable to our study. 16 Comparisons between free auto-graft, rotational flap, and application of per-operative Mitomycin C (MMC) have shown that free auto-grafts have the lowest rate of recurrence. This is comparable to the per-operative application of MMC but has the advantage of avoiding all the potential complications associated with its use. 8 However, these results are based on surgeries performed on eyes that presented with either primary or recurrent pterygia. For eyes with primary pterygia, the recurrence rate is comparable between conjunctival flap transplant and free conjunctival auto-graft procedures and that of per-operative application of MMC. The site from where the transplant tissue is harvested may have implications on future surgery or surgeries that the eye might require. Surgeons prefer inferior bulbar conjunctiva as harvesting tissue from the superior zone may have negative outcome implications if a future filtration surgery is required. 17 The preferred site, for all patients who underwent free conjunctival auto-graft procedure, for harvesting graft tissue was the superior conjunctiva. Surgeons' familiarity was the main factor for site selection. In order to ensure that the vital tissue was not compromised, we excluded all cases from the study that might require filtration surgery. Appropriate size of the graft tissue can lead to lower recurrence. Graft tissue that is relatively larger than the host implant site has been shown to reduce recurrence. 18 In all the auto-graft transplant cases we used a graft tissue that was atleast 1 mm larger in all dimension as compared to the host site. Large pterygium size was associated with a greater incidence of recurrence in our study which is consistent with published literature. 19 All the cases with recurrence in CAG had pterygia categorized as large, while in CRG two of the three patients presenting with recurrence had a large pterygium, however, this difference is not statistically significant (p=0.60). The complications observed in both groups were benign in nature (Table II). We observed no significant differences in postoperative complications between the two groups (p=0.60). In CAG group 2 patients presented with graft edema, while one presented with granuloma formation. In CRG 3, cases had post-operative edema, while one case had granuloma formation. In both groups, the granuloma responded to standard postoperative treatment regimen. Rotational flap surgery has been shown to have lower incidence of tissue edema as opposed to free graft surgeries. 16 We followed the guidelines of Taylor for recurrent pterygia surgery and applied to our CAG cases. An additional suture was placed at the center of the grafted tissuue. 20 This is most likely responsible for a lower incidence of graft edema in our groups. Male gender has been shown to be associated with development 21 and recurrence of pterygium after surgery. 22 These findings are consistent with those of the published literature (Tables I and II). Age of cases was considered in evaluation as it has not been conclusively shown that age influences recurrence of pterygium after surgery. 19,22,23 CONCLUSION Based on comparable recurrence and complication rates with the benefit of lower surgical time, the authors recommend conjunctival rotational flap procedure for cases elected for pterygium surgery to reduce postoperative recurrence. REFERENCES 1. Di Girolamo N, Chui J, Coroneo MT, Wakefield D. Pathogenesis of pterygia: role of cytokines, growth factors, and matrix metalloproteinases. Prog Retin Eye Res 2004; 23: Coroneo MT, Di Girolamo N, Wakefield D. The pathogenesis of pterygia. Curr Opin Ophthalmol 1999; 10: Di Girolamo N, Coroneo MT, Wakefield D. UV B-elicited induction of MMP-1 expression in human ocular surface epithelial cells is mediated through the ERK1/MAPKdependent pathway. Invest Ophthalmol Vis Sci 2003; 44: Golu A, Gheorghisor I, Balasoiu AT, Balta F, Osiac E, Mogoanta L, et al. 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