|Year : 2021 | Volume
| Issue : 4 | Page : 359-363
Donor site management in primary pterygium excision with conjunctival autograft – Less is more!
Radhika Natarajan, Ankit Anil Harwani
Department of Cornea and Refractive Surgery, Medical Research Foundation, Chennai, Tamil Nadu, India
|Date of Submission||30-Jul-2021|
|Date of Acceptance||17-Sep-2021|
|Date of Web Publication||21-Dec-2021|
Dr. Ankit Anil Harwani
Department of Cornea and Refractive Surgery, Medical Research Foundation, Chennai - 600 006, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Purpose: The aim of this study is to assess spontaneous healing of the conjunctival donor site after primary pterygium surgery and its implications. Materials and Methods: This was a prospective study of one hundred primary pterygium surgeries with superior conjunctival autografting. Ninety nasal pterygia, eight double-headed pterygia, and two temporal pterygia were included. The conjunctival epithelialization in the donor harvest site, corresponding superior limbal pigmentation, presence of any visible scarring, and mobility of the conjunctiva were documented after the surgery. The patients were reviewed on day 1, day 4, at 1 week, and 1 month after surgery, and then followed up every 4 months for a minimum of 2 years. Mean with standard deviation, percentages, and paired sample t-test were the statistical methods employed in the study. Results: Progressive pterygium with corneal involvement (87%) was the most common indication for surgery. Conjunctival epithelization was complete at the donor site within a week of surgery in all cases. At 1 month, there was no scarring or vascularization at the donor site in any of the cases. The limbus appeared intact with its pigmentation. The healed conjunctiva showed good mobility in all the cases. These were confirmed on anterior segment optical coherence tomography. There were no donor site-related complications. These findings remained stable over 2 years. Conclusion: Not closing the donor harvest area seems to allow spontaneous donor site healing in uncomplicated primary pterygium excision surgery with a superior conjunctival autograft. This avoids in-folding of unequal tissues and resultant scarring. An undisturbed Tenon's layer at the donor site acts as a scaffold for smooth conjunctival healing. The healed conjunctiva remains mobile with an intact limbus.
Keywords: Conjunctival autograft, donor site, pterygium
|How to cite this article:|
Natarajan R, Harwani AA. Donor site management in primary pterygium excision with conjunctival autograft – Less is more!. TNOA J Ophthalmic Sci Res 2021;59:359-63
|How to cite this URL:|
Natarajan R, Harwani AA. Donor site management in primary pterygium excision with conjunctival autograft – Less is more!. TNOA J Ophthalmic Sci Res [serial online] 2021 [cited 2022 Dec 10];59:359-63. Available from: https://www.tnoajosr.com/text.asp?2021/59/4/359/333154
| Introduction|| |
The most common and successful surgery performed for progressive primary pterygium is excision of the pterygium with conjunctival autograft. The superior bulbar conjunctiva is the site from which the conjunctival autograft is usually taken as it is relatively protected by the upper eyelid and is easily accessible to the surgeon, although bulbar conjunctiva from other sites can also be used.
Various techniques of conjunctival autografting have been discussed in literature, but how to manage the donor site after harvesting the graft is hardly mentioned. Postoperative conjunctival healing, patient comfort, prevention of scarring, prevention of infection or granuloma formation, and preservation of the superior conjunctiva for potential future glaucoma filtration surgery are some of the concerns regarding donor site management.,
While there exist methods to close the donor site, we found that not doing a closure leads to better conjunctival healing under controlled circumstances. The aim of this study is to assess spontaneous healing of the conjunctival donor site after primary pterygium surgery and its implications.
| Materials and Methods|| |
This study was approved by the institutional review board and ethics committee. This was a prospective study of one hundred primary pterygium surgeries with superior conjunctival autograft. Ninety patients who had nasal pterygia, eight who had double-headed pterygia, and two with temporal pterygia were included. The indications for surgery included progressive pterygium, corneal involvement of more than 1 mm into the limbus, astigmatism of more than ± 0.75 diopter due to the pterygium, patient symptoms, and cosmetic indication. None had ocular movement restriction. Recurrent pterygia, pseudo pterygia, and patients with ocular surface chemical or thermal burns or cicatrizing conjunctival disease were not included.
Standard surgical steps for pterygium excision with superior conjunctival autograft were followed. The conjunctiva was opened over the pterygium. The pterygium was separated from the surrounding Tenon's capsule and fibrovascular tissue until anterior to the extraocular muscle insertion. Once the pterygium was freed, the neck was cut, and the body of the pterygium was excised. Abnormal fibrovascular tissue was removed from the bed. Mild cautery was done for hemostasis. The head of the pterygium was then dissected off the cornea.
The size of the conjunctival defect was measured in two dimensions. A superior conjunctival autograft was marked out 1 mm more than the defect in length and width, with one edge at the superior limbus. Mild wet-field cautery marks (Infiniti Vision System, Alcon Laboratories, Inc., Fort Worth, TX, USA) were used to delineate the graft [Figure 1]. Using the plane of separation opened up by the cautery marks, the conjunctival graft was carefully dissected from the Tenon's capsule. Dissection was done from the posterior edge toward the limbus. Limbal tissue was not specifically included as conjunctival autograft and conjunctival limbal autograft have been reported to have comparable surgical outcomes. The conjunctiva was flipped over to remove any attached wisps to make the graft free of Tenon's capsule and kept it as thin as possible. Care was taken to leave the underlying Tenon's layer intact without any buttonhole [Figure 2]. The graft was then excised at the limbal edge, and hemostasis achieved in the graft bed with mild cautery.
|Figure 1: Blue arrow marks showing adjacent cautery marks outlining the graft|
Click here to view
The conjunctival autograft was then slid across the cornea, maintaining orientation, and stuck with reconstituted fibrin glue (Tisseel, Baxter Healthcare, CA, USA) over the episclera in the area of the pterygium excision, taking care to approximate the conjunctival edges. The graft was split and used for the double-headed pterygia of which two cases needed additional amniotic membrane graft to cover the defect. These are not described in detail as the focus of this article is the healing of the donor site of the conjunctival autograft. The donor site, which now had an area of intact Tenon's capsule, was not closed. The eye was patched with 5% Povidone Iodine eye drops.
Postoperatively, topical antibiotic was given for a week, and lubricating eye drops for a month. Topical betamethasone drops were started four times a day after the healing of the corneal epithelial defect and tapered weekly. The patients were reviewed on day 1 and day 4, at 1 week, and 1 month after surgery, to look for complications and to monitor healing of the corneal epithelial defect and the conjunctival donor site. Patients were then followed up every 4 months for a minimum of 2 years.
At the 1 month follow-up, a comprehensive ophthalmic examination was done with an emphasis on the appearance of the superior conjunctival donor site. The conjunctival epithelialization in the area of donor harvest, the superior limbal pigmentation in the corresponding clock hours, presence of visible scarring, if any, and the mobility of conjunctiva in this area checked using a sterile cotton tip applicator with topical anesthetic were documented.
Anterior segment optical coherence tomography (AS-OCT) (Casia SS-1000°CT; Tomey, Nagoya, Japan) was performed at 1 month follow-up, to confirm normal anatomical structure of conjunctiva in the donor site and absence of scarring. The normal conjunctival appearance of hypo reflective epithelial layers and hyperreflective stromal tissue and Tenon's capsule was noted postoperatively on AS-OCT. Homogenic reflectivity indicated a lack of scarring.
| Results|| |
A hundred patients with progressive pterygia were enrolled prospectively in the study, out of which 61 were males and 39 females. The mean age was 56 ± 13 years. Ninety patients had nasal pterygia, eight had double-headed pterygia, and two had temporal pterygia [Diagram 1]. All patients hailed from the Indian subcontinent. There was no other significant associated history. They all underwent pterygium excision with a superior conjunctival autograft.
Progressive pterygium with corneal involvement (87%) was the most common indication, followed by symptomatic (32%), astigmatism (18%), and cosmetic indications (7%) [Table 1]. Thirty-four percent of the cases had more than one indication for undergoing the procedure. The average follow-up was of 18 months (range 8 days to 9 years).
The extent of pterygium over the cornea was found to be 2.6 mm ± 0.95 mm (range 1 mm–6.2 mm). The length of the conjunctival autograft ranged from 5 to 7 mm and the width from 4 to 5 mm, respectively. The graft was oversized by 1 mm in dimensions as compared to the conjunctival defect caused by the pterygium excision. The average area of donor site used was 25.29 mm2 ± 7.45 mm2 (range 14 mm2–40 mm2). There was no buttonhole formation in any of the cases while dissecting the Tenon's free conjunctival graft. There were no other intraoperative complications.
In the first postoperative week, mild temporal graft retraction occurred in two cases exposing the episclera which was managed by taking sutures. Two patients had developed an early recurrence of the nasal pterygium at the 1 year follow-up. As these were nonprogressive and not crossing the limbus, it was decided to observe them with symptomatic treatment.
Conjunctival epithelization at the donor site was complete within a week of surgery in all 100 patients as evidenced by slit-lamp examination. This was confirmed by the absence of sterile fluorescein staining. At 1 month follow-up, there was no scarring at the donor site in any of the cases [Figure 3]. No vascularization was noted, and the limbus appeared intact with its pigmentation in all the cases. The mobility of the healed superior conjunctiva was tested with a sterile cotton-tip applicator with topical anesthetic by the same observer [Figure 4]. This test showed good mobility in all 100 cases.
AS OCT of the conjunctiva in the donor site showed hyporeflective epithelial layer, hyperreflective stroma, and hyporeflective Tenon's capsule conforming to normal appearance [Figure 5]. No separation of layers, abnormal thickening or scarring was noted, indicating normal healing of conjunctiva after donor harvest for autograft during pterygium excision. Preoperative average K reading and postoperative average K reading did not show any statistically significant difference on paired sample t-test (P = 0.156).
|Figure 5: Anterior segment optical coherence tomography of the conjunctiva in the donor site showing hypo reflective epithelial layer (yellow arrow head), hyper reflective stroma (orange arrow head) and hypo reflective Tenon's capsule (green arrow head) conforming to normal appearance|
Click here to view
Follow-up was for at least 2 years and these findings remained unaltered at all follow-ups. There were no donor site-related complications in any of the cases.
| Discussion|| |
Pterygium excision with conjunctival autografting is considered to be the gold standard in the management of progressive primary pterygium. This procedure reestablishes the ocular surface and has a low chance of pterygium recurrence. Conjunctival autografting with and without the inclusion of limbal tissue has been shown to provide similar surgical results and low recurrences, and the former technique was used in our cases.
The conjunctival autograft is usually taken from the superior bulbar conjunctiva of the same eye. This location enjoys protection from the harmful radiation of the sun as it is covered by the upper eyelid and also provides easy surgical access. The harvesting of this conjunctiva leaves the underlying Tenon's layer bare, which ideally should heal without excessive inflammation, irritation, granuloma formation, or scarring. Hence, the donor harvest site should also be dealt with appropriately during the surgery so that it can heal quickly without complications and also retain its mobility for possible future glaucoma filtration surgery.
The usual technique used to close the donor conjunctival defect at the harvest site is to drag down the cut edge of the conjunctiva and approximate it at the limbus. This is then secured with either reconstituted fibrin glue in the bed or by suturing the edges. However, as a patch of the conjunctiva has been excised and the underlying Tenon's layer is intact, there is a mismatch between the length of the two layers. Hence, while dragging down the cut conjunctival edge, due to the difference in the lengths of both these layers, an in-folding of the Tenon's layer occurs. This can lead to scarring, the very thing that we are trying to prevent by doing the donor site closure. This may be avoided by making relaxing incisions while bringing the conjunctiva down or by undermining and mobilizing the surrounding conjunctiva before covering the defect. However, this would make a simple primary pterygium surgery more invasive.
Another way of dealing with the autograft harvest site, especially in primary pterygium cases, is to leave it alone to heal spontaneously which was done in our cases. It was found that, under the cover of the upper lid, the conjunctival epithelium from forniceal niche grows as a sheet over the intact Tenon's layer which acts like a basement membrane or a scaffold. Patients were not very symptomatic postoperatively, as the lid covered the exposed Tenon's capsule, and they were also on anti-inflammatory eye drops, though a validated questionnaire was not employed.
The superior conjunctiva thus healed retains excellent mobility without significant scarring and is amenable for future filtration surgery. The limbus appears undisturbed in this region, and it may be possible to re-harvest from the same site should the pterygium recur., When this method was tried and tested in our cases, there were no intraoperative or postoperative donor site-related complications. AS OCT done at 1 month follow-up confirmed normal appearance of the healed conjunctiva at the donor site.
However, the donor site does need to be closed in some situations. For example, if an unusually large autograft is required or if the Tenon's layer is already fibrosed due to the previous scarring, then the conjunctival re-epithelization can be delayed leading to ocular surface inflammation and subsequent complications. Hence, it is better to mobilize the conjunctiva with relaxing incisions and close the donor site defect with glue or sutures in such cases. This is usually needed in recurrent pterygia, pseudo pterygia, or ocular surface thermal or chemical burns. However, in the context of simple primary pterygium excision with conjunctival autograft surgery, closure seems to be needed only in the event of inadvertent buttonhole in the Tenon's layer at the donor harvest site as this can lead to infection, necrosis of sclera or scarring. On the other hand, if the Tenon's layer is intact, the conjunctiva epithelium grows over the defect to close it.
The donor conjunctival graft should be dissected as thin as possible and relatively Tenon's free to avoid postoperative graft retraction and ensure reduced chances of recurrence. It has also been observed that the fibrin glue used to secure the conjunctival graft in place can cause reactionary graft edema in some cases due to antigenic substances present in fibrin glue, and this can lead to Dellen formation in the adjacent cornea. Having a thin graft to begin with helps reduce this problem as well.
One way to obtain a thin, relatively Tenon's free graft without buttonholing, is to inject fluid between the conjunctival epithelium and Tenon's layer. However, sometimes, the fluid can get accidentally injected beneath the Tenon's layer which can cause the conjunctival epithelium and the Tenon's layer to get jammed up, making the dissection more difficult. In our series, the method used was to mark the borders of the graft area with fine cautery. The bare area after the pterygium excision was measured with calipers in two dimensions. Low energy continuous cautery marks were applied, outlining the superior conjunctival graft on three sides with the fourth side at the limbus. The graft was oversized by 1 mm to account for shrinkage of tissue due to cautery. Differential shrinkage of the conjunctiva and the Tenon's layer occurred due to the cautery with the conjunctiva shrinking more and the Tenon's layer shrinking a bit less. This enabled the dissecting scissors to be inserted easily between the two layers, and a plane of cleavage was readily obtained after that.
The graft was flipped over the cornea to remove any wisps of the remaining Tenon's tissue and then reoriented again. These steps of obtaining a correct dissection plane, avoiding button-hole formation, and dissecting a thin and Tenon's free graft were imperative to the success of the surgery as well as problem-free donor site healing. The conjunctival epithelial defect then healed completely within a week time in all cases. This conjunctiva showed retained mobility and the corresponding limbus was undisturbed.
| Conclusion|| |
To conclude, not closing the harvest area seems to allow spontaneous donor site healing in uncomplicated primary pterygium excision surgery with a superior conjunctival autograft. This avoids in-folding of unequal tissues and resultant scarring. An undisturbed Tenon's layer at the donor site acts as a scaffold and facilitates smooth conjunctival epithelial healing.
Thus, superior conjunctival autograft donor site closure is not necessary in primary pterygium surgery, and this approach leaves the superior limbal conjunctiva mobile and scar free. The healed conjunctiva retains an intact limbus.
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Conflicts of interest
There are no conflicts of interest.
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