Pterygium is a common external ocular surface disease characterized by wing-shaped fibrovascular overgrowth of conjunctiva onto the cornea causing significant ocular irritation, inflammation, and corneal astigmatism. The risk factors of pterygium are ultraviolet exposure, geographical latitude, outdoor activity, dry eye, genetic predisposition, increasing age, male sex, races, and low educational level.1,2 Thailand is situated in the pterygium belt, between 37° north and south latitude, which exposes to high ultraviolet intensity and the national occupation is mainly agricultural. Therefore, pterygium is commonly found in Thailand which causes significant ocular disturbance that eventually leads to surgical excision. However, there is a variation in surgical techniques and the recurrence rate. Moreover, there are new surgical techniques that facilitate the ease of surgery and the surgical outcome,3 for example the use of AMT4–6 fibrin glue7–9 and Pterygium Extended Removal Followed by Extended Conjunctival Transplant (P.E.R.F.E.C.T.)10
This survey is to evaluate the most preferred surgical techniques, how significant the number of new surgical techniques currently used is, the ideal surgical technique, and to find out the obstacles to the ideal surgical technique for both primary and recurrent pterygium among Thai ophthalmologists.
This descriptive cross-sectional study was conducted between September 21 and December 21, 2016, using SurveyMonkey, an online questionnaire and data collection platform. The participants were Thai ophthalmologists who were members of the RCOPT.
The sample size of the survey was calculated using the formula n = p (100–p)Z2/E2 with p = 23%, 95% level of confidence, 5% margin of error resulted in the number of 272 samples.
The emailed questionnaires were sent out via RCOPT Express (email@example.com) to 1150 RCOPT members. The study was approved by King Chulalongkorn Memorial Hospital (KCMH) research committee (IRB Approval number 241/59) and was conducted in strict adherence to the tenets of the Declaration of Helsinki, the Belmont Report, and CIOMS Guideline. The online survey tool was conducted confidentially and anonymously, therefore the researcher could not identify the specific participant.
512 of 1150 questionnaires were collected (44.5%). 44 questionnaires were incomplete, 30 questionnaires were invalid and excluded. Therefore, 438 completed questionnaires (38.1%) were used for analysis.
From 438 participants, 262 were females (59.8%), and 176 were males (40.2%). The majority of respondents were in 31- to 35-year age group, accounting for 34.5% of all respondents. General ophthalmologists were the major respondent in this study (61.4%). The corneal specialist accounted for 13.9%. Most of the respondents (46.8%) lived in a central region of Thailand (Table 1).
For primary pterygium, 164 respondents (37.4%) reported that BST was the most preferred technique, followed by CAGT from 149 respondents (34%) and pterygium excision with AMT (26.3%). Most of the respondents (87.4%) did not use the adjuvant therapies in primary pterygium (Table 2).
For recurrence pterygium, 197 respondents (44.9%) preferred CAGT and 184 respondents (42%) preferred pterygium excision with AMT. Adjuvant therapies were used by 40.9% of respondents (Table 2).
For BST, a total of 164 respondents choose BST for primary pterygium, 121 of 164 respondents were general ophthalmologists (74%), 39 were noncornea specialists (23%), and 5 were cornea specialists (3%), about the same percentage was also found in 45 respondents choosing BST for recurrent pterygium.
53% of respondents preferred nonabsorbable suture for graft attachment. Only 3.2% of respondents used fibrin glue.
Postoperative Topical Steroid
50% of respondents prescribed topical steroid eye drops for 4 to 8 weeks postoperatively.
No complication was reported in 38.6% of the respondents but 28.8% experienced excessive bleeding (Table 3).
Recurrence was the most common early and late postoperative complication (22% and 76.5% respectively). Steroid-induced ocular hypertension (9.6%) was the second most common late postoperative complication. Other complications were listed in Table 3.
Ideal Surgical Techniques and Obstacles
The ideal surgical techniques for primary pterygium were pterygium excision with graft, either CAGT (42.4%) or AMT (39%).
For recurrent pterygium, most of the respondents preferred AMT with adjunctive therapy (27.4%), followed by CAGT with adjunctive therapy (26.5%) as the ideal surgical technique.
Most of the respondents (65.3%) wished to use mitomycin C as the adjunctive therapy; however, 121 respondents (27.6%) preferred not to use adjunctive therapy.
The ideal techniques which are currently used in clinical practice for primary pterygium and recurrence pterygium were reported by 53.9% and 45.7% of respondents, respectively (Table 4).
The inaccessible and unaffordable amniotic membranes or fibrin glues were most reported as the obstacles to the ideal techniques in both primary and recurrent pterygium surgery (52.4% and 62.3% respectively, average 58%). Concerning about complications (average 26%), lack of experience in surgical procedures (average 25%), large number of patients in the surgery waiting list, prolonged surgical time, and need for conjunctiva preservation in glaucoma patients were also reported (Table 4).
There are many surgical techniques for pterygium which include BST, simple conjunctival closure, conjunctival flap, conjunctival or amniotic membrane grafting, and adjuvant therapy. Hirst et al11,12 performed a survey in 1991 and 2001 which was 10 years after the first survey. Simple excision with conjunctival flap followed by bare sclera was most used for primary pterygium; simple excision with beta irradiation was most selected for recurrent pterygium. The second survey in 2001 showed that simple excision with conjunctival flap was still the most selected procedure; more alternative techniques such as mitomycin C application and conjunctival autograft were also reported. Recent studies showed that techniques like bare sclera and primary conjunctival closure are considered as inferior and they yielded high rates of recurrence between 50% and 80%,13 whereas pterygium excision with conjunctival or amniotic membrane graft has presented the acceptable recurrence rate between 5% to 20% and 36% respectively. New surgical techniques were also developed to minimize recurrence and complication. However, the survey of pterygium surgery is very scarce. Another survey was conducted almost 10 years later by Chaidaroon et al.14 Changing trends in surgical technique are expected, for example the beta irradiation becoming less popular and shifting toward grafting.
In 2010, Chaidaroon et al14 performed a questionnaire-based survey and received responses from 414 Thai ophthalmologists; 74.5% of the respondents were general ophthalmologists. The study found that 36% of the respondents used CAGT without adjunctive therapy in primary pterygium, whereas 93 respondents (23.3%) performed BST.
Kampitak and Bhornmata15 reviewed 307 medical records of the patients who had pterygium excision at Thammasat University Hospital, Pathum Thani, province adjacent to northern Bangkok, from October 2010 to September 2013. They found that AMT technique (96.7%) was the most performed procedure. This review showed high percentage of AMT technique because Thammasat University Hospital was a medical school and residency training center which could provide amniotic membrane for both service and training.
Current studies showed different results from the latest survey by Chaidaroon et al,14 which showed that BST was the most selected procedure for primary pterygium (37%). The demographic data of the respondents between these 2 studies were comparable (Table 5). However, our survey showed that CAGT was still the second most preferred technique and received slightly different percentage from BST. We can conclude that the trend of surgical techniques for primary pterygium in Thailand has not changed much in previous 6 years. Techniques such as P.E.R.F.E.C.T. and AMT are less applied.
The ideal technique for primary pterygium was pterygium excision with graft (either conjunctiva or amniotic membrane graft) and 53.9% of respondents reported that they are currently using the ideal technique. Grafting requires longer surgical time and more surgical skills; hence, grafting may not be considered in the setting of busy clinics with large number of patients in the surgery waiting list. On the contrary, fibrin glue can help shorten the surgical time in such environment, but it is expensive, unavailable in most hospitals, and also requires surgical experience. Furthermore, some physicians wish to preserve conjunctiva for future filtering surgery. We believe that these reasons explain why BST was most selected from our survey. Even in the recurrent pterygium, BST was still used in 10.3% of respondents, albeit only 0.7% of the respondents believing BST as the ideal technique for recurrent pterygium. P.E.R.F.E.C.T. was selected as the ideal technique from 8% and 10% of the respondents for primary and recurrent pterygium, respectively. This technique is a marked modification of the existing method of conjunctival autograft transplant described above,16 which gave the lowest recurrent rate.3 The low percentage of this technique may be due to the fact that this technique is new and still not recognized by ophthalmologists and residents.
For recurrent pterygium, most respondents (42%–44%) preferred pterygium excision with graft (either conjunctival or amniotic membrane graft) which is known to provide lower recurrence rate compared with BST. The majority (58.4%) of respondents do not use any adjuvant therapy; 30.6% use mitomycin C for recurrent pterygium. However, grafting with adjuvant therapy was mostly chosen as the ideal surgical technique. Up to 65.3% of respondents reported that they wished to use mitomycin C for recurrent pterygium surgery, but inexperience and concerns about complications were the main obstacles to the use of adjuvant therapy.
The complication in our study was comparable to the previous survey by Chaidaroon et al.14 The most common intraoperative and postoperative complications were excessive bleeding and recurrence, respectively. Recurrence may be related to a preference of the BST.
To the best of our knowledge, this was the first survey of pterygium surgery that included primary and recurrent pterygium in Thailand along with the ideal surgical techniques. The number of participants was the greatest among previous reports.11,12,14,15 This gave us the insights into the opinions and obstacles that Thai ophthalmologists encountered in pterygium surgery. We hope that this study can provide useful information on improving the quality of pterygium surgery in Thailand, decreasing pterygium recurrence, and also helping shape the training program and instruction course for Thai ophthalmologists. Techniques such as P.E.R.F.E.C.T., grafting, fibrin glue application along with the better distribution of amniotic membrane/glue should be promoted to facilitate the best surgical outcome.
The limitation of this study included the questionnaire-based nature of the survey; a sample size of 438 respondents not being able to reflect all 1150 Thai ophthalmologists. The type of pterygium and the age of patients were not mentioned; atrophic pterygium in a very elderly patient may be suitable for BST in some setting. Multiple and detailed questions took longer time to complete, resulting in a significant number of invalid or incomplete responses.
BST and CAGT were the most preferred surgical techniques for primary and recurrent pterygium, respectively. Techniques such as P.E.R.F.E.C.T. and AMT were still less applied. The ideal technique for primary pterygium was CAGT and that for recurrent pterygium was pterygium excision with graft (either conjunctiva or amniotic membrane graft) with adjuvant therapy. Around half of the surveyed ophthalmologists faced obstacles to the performance of an ideal surgical procedure for patients. The most frequently reported obstacle was the inaccessible amniotic membranes/fibrin glues. The recurrence of pterygium was still the major postoperative complication. To emphasize, both quality and quantity measures in pterygium surgery techniques and supplies are yet to be improved.
We would like to acknowledge all Thai ophthalmologists who participated in this survey, RCOPT staffs who helped the distribution of online questionnaires, and the Department of Ophthalmology, King Chulalongkorn Memorial Hospital, Chulalongkorn University.
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