Pterygium excision and conjunctival autograft: A comparative study of techniques

Abstract

BACKGROUND:

Use of conjunctival autograft following excision has reduced the recurrence rate of primary pterygium. This study compares the use of fibrin glue, autologous blood, and sutures in placing the conjunctival autograft in reference to surgical time taken, postoperative discomfort, and recurrence during follow-up.

MATERIALS AND METHODS:

Sixty patients with primary pterygium were included in the study and divided into three groups. In Group I, autograft was attached in place with help of 10-0 polyamide monofilament suture; in Group II, with autologous blood; and in Group III, with fibrin glue. All three groups were compared in terms of surgical time, postoperative discomfort, and recurrence.

RESULTS:

The average surgical time taken was least with fibrin glue group (Group III), i.e., 36.2 min, followed by 44.8 min with autologous blood group (Group II) and maximum of 53.3 min with suture group (Group I). Postoperative discomfort was seen maximum in th suture group (Group I) and was minimal in the fibrin glue group (Group III). At the end of final follow-up at 6 months, one case of recurrence was seen in both Group I and Group II. No recurrence was seen in Group III.

CONCLUSION:

The study concluded that fibrin glue remains the most effective method for attaching conjunctival autograft in pterygium surgery with least surgical time and postoperative discomfort. Autologous blood is an effective alternative which is easily available, economical, vis a vis fibrin glue with less surgical time and postoperative discomfort. Use of sutures is an older technique with maximum surgical time and postoperative discomfort. Recurrence is least with fibrin glue.

Introduction

Pterygium, a word derived from “pterygion” (ancient Greek for wing), is a wing-shaped, fibrovascular overgrowth arising from subconjunctival tissue extending across the limbus onto the cornea. It is a degenerative condition of the subconjunctival tissue which proliferates as vascularized granulation tissue to invade cornea, destroying superficial layers of stroma and Bowman's membrane, the whole being covered by conjunctival epithelium.[1,2]

The prevalence rate of primary pterygium varies from 0.7% to 31% in various populations around the world.[3] Working outdoors increase the risk 1.5-fold. Although exact etiology is not known, risk factors include genetic predisposition, chronic environmental irritations such as dust, dryness, heat, and ultraviolet rays.[4,5]

A pterygium is generally managed conservatively unless it is progressing toward pupillary area causing excessive astigmatism, resulting in decreased vision. The reported rates of recurrence are 25%–45% after simple excision of primary pterygium.[6] The high rates of the recurrence have been explained by the theory of corneal limbal stem cell deficiency. Spaeth et al.[11] in a study explained the modification of the surgical technique using conjunctival autograft for covering bare sclera after pterygium excision, which resulted in decreased recurrence rates.[7]

After pterygium surgery, the conjunctival autograft is secured in the place with either absorbable or nonabsorbable sutures. The presence of sutures is associated with various complications, i.e. discomfort, increased lacrimation, and at times suture-related granuloma or abscess. With the invention of newer alternatives such as fibrin glue and autologous blood, suture-related complications have come to a halt. The use of fibrin glue during pterygium surgery was first described by Cohen and McDonald in 1993.[8] Since then, various studies have been published regarding the safety and efficacy of fibrin glue in ophthalmic surgery.

As the fibrin glue is a blood-derived product, its use is associated with the risk of transmission of blood-related diseases. In these cases, autologous blood is a good alternative as it is easily available, only exception being patients who regularly take aspirin or other blood thinners or who suffer from a coagulation factor deficiency.[9]

This study has been undertaken to compare the efficacy of fibrin glue and autologous blood as compared to traditional use of sutures in attaching the conjunctival autograft. To the best of our knowledge, very few studies have reported a comparison of all three modalities, i.e., fibrin glue, autologous blood, and sutures.

Materials and Methods

Sixty patients reporting with primary pterygium were recruited in the study after obtaining informed consent. A comprehensive evaluation was done, which included patient's biophysical profile, relevant medical and ocular history, and thorough ophthalmic examination. Patients with recurrent pterygium or history suggestive of any hypersensitivity to human blood products were excluded from the study. Patients were divided into three groups of 20 each. In all three groups of patients, pterygium excision with conjunctival autografting was done. However, the technique of securing autograft was different in all three groups. In the first group (Group I) of 20 patients, autograft was secured in place with the help of 10-0 polyamide monofilament suture; in the second (Group II) with autologous blood; and in the third group of 20 patients (Group III), fibrin glue was used to secure the autograft in place.

Surgical procedure

All surgeries were performed under local anesthesia using a combination of 2% lignocaine and 0.5% bupivacaine. Peribulbar block was followed by cleaning and sterile draping. Superior rectus bridle suture was applied using 3-0 silk. Pterygium was excised using a sharp blade and at times crescent blade was also used. Bleeding was controlled with pressure from cotton buds. No cauterization was done. The area of conjunctival defect was measured with a caliper and a conjunctival limbal autograft measuring the same size as the defect was obtained from the supertemporal quadrant of the bulbar conjunctiva. The graft was flipped over the cornea and brought near the area of bare sclera formed by excision of the pterygium. Proper orientation was maintained while placing the graft. Depending on the group in which patients were allocated to, conjunctiva-limbal autograft was secured in place.

In Group I, multiple interrupted 10-0 polyamide monofilament sutures were used to secure autograft in place [Figure 1]. Typically, autograft was anchored to sclera at limbus first with single superior and inferior suture. Rest of autograft margin was attached with two or three interrupted sutures.

Figure 1.

Conjunctival autograft with sutures

In Group II, a thin film of blood clot was formed over the bare area, and any active bleeding was stopped by direct tamponade. The conjunctiva-limbal graft was taken from supertemporal quadrant and placed over the blood film in the bare area [Figure 2]. The edges were held with forceps, usually for 3–5 min so that graft gets fixed adequately.

Figure 2.

Conjunctival autograft with autologous blood

In Group III, fibrin glue was used to attach the autograft in place. The glue was prepared from TISSEL Kit which is manufactured by Baxter AG, Austria. The mixing of the component was done properly as per the directions. Initially, the aprotinin solution (small blue bottle) was mixed with sealer protein concentrate (large blue bottle), followed by warming. The thrombin solution is prepared by mixing thrombin 4 (black bottle) with calcium chloride solution (small black bottle) for slow clot setting. The slow clotting gives adequate time to a surgeon to align the graft while attaching. When solutions are prepared, they are drawn into two different syringes. These syringes are then placed into the duploject injector which is specially designed so that depressing the common plunger exerts equal pressure on both the syringes [Figure 3]. Two to three drops of this solution was placed on the scleral bed, and the conjunctival autograft was immediately flipped over the area of conjunctival defect [Figure 4]. The graft was quickly smoothened out with a nontoothed forceps and edges were aligned properly while the fibrin glue clots.

Figure 3.

Fibrin glue Kit with Duplojet injector

Figure 4.

Conjunctival autograft with fibrin glue

Surgical time was noted from placement of lid speculum to its removal [Figure 5]. At the end of the surgery, superior rectus suture was removed and sterile eye pad was applied. Postoperatively, subjects in all the groups were treated with eye drop ofloxacin with prednisolone four times a day for 1 week which was then tapered over a period of next 2 weeks. They were also prescribed artificial tear eye drops for 4 weeks. All patients were seen on day 1, day 3, day 7, day 14, 1 month, 3 months, and 6 months postoperatively [Table 1]. Patients were evaluated regarding the presence of pain, foreign body sensation, tearing, and discomfort. During each postoperative visit, the status of the autograft and development of possible complications was noted. At the final postoperative visit at 6 months, the presence of recurrence, if any, was noted.

Figure 5.

Graphical representation of mean surgical time

Table 1.

Postoperative evaluation

Results

In Group I, there were 13 males (65%) and 7 females (35%). The age of patients in the group ranged from 27 years to 78 years, with average being 50.7 years.

In Group II, there were 16 males (80%) and 4 females (20%). The age of patients in the group ranged from 22 years to 66 years, with average being 43.5 years.

In Group III, there were 10 males (50%) and 10 females (10%). The age of patients in the group ranged from 26 years to 67 years, with average being 48.4 years.

The average surgical time taken for Group I was 53.3 min, for Group II was 44.8 min, and for Group III was 36.2 min. The mean surgical time was least for Group III (fibrin glue) followed by Group II (autologous blood) and maximum for Group I (suture).

Pain and foreign body sensation were present in all 20 cases of Group I on 1^st postoperative day which continued for 1 week though intensity decreased progressively and finally patients were pain-free on around 3 months. In the Group II, pain and foreign body sensation were seen in few cases which vanished earlier as compared to Group I. In the Group III, these symptoms were seen only in six patients and these too were asymptomatic after 1 week.

Subconjunctival hemorrhage was seen in two patients of Group I and one patient of Group II which stabilized over a period of 1–2 weeks. Subconjunctival hemorrhage was characteristically absent in Group III. Graft retraction was seen in one case of Group I and Group II each. In Group III, there was no case of graft retraction seen.

All patients were evaluated for signs of recurrence of pterygium. Recurrence was noted in one case of Group I (suture) and Group II (autologous blood) each at 3 months postoperatively. At the end of final follow-up at 6 months, no fresh recurrence was seen. No recurrence was seen in Group III (fibrin glue).

Discussion

Pterygium is a common ophthalmic condition seen mostly in dry, dusty areas. Various surgical options are available to manage this condition with prevention of recurrence as the primary aim. It is still an ongoing debate regarding the “ideal” pterygium surgery.[10] Use of a conjunctival graft to cover the bare sclera after excision of pterygium has been reported to be the most effective method of lowering recurrence rate (2%–9%) and complications.[11,12,13,14] The transplantation of conjunctiva-limbal autograft helps cover the limbal stem cell deficiency.[15] Care should be taken to include the limbal part while harvesting the graft so that stem cells are included.[14]

Although autologous limbal conjunctival grafting is an effective method for prevention of recurrence after pterygium surgery, suturing of the autograft is difficult and necessitates surgical experience and technical skill.[16] Furthermore, sutures may cause patient discomfort, symblepharon, or graft rupture.[17,18] Biological tissue glue, such as fibrin glue, has come as a novel alternative for securing the graft as it causes less complications and postoperative discomfort. Fibrin glue has been used in ophthalmology for conjunctival wound closure, oculoplastic or orbital surgery, filtering bleb dehiscence, lamellar keratoplasty, and amniotic membrane transplantation.[19] Ti et al.[20] showed that postoperative inflammation increases the risk of pterygium recurrence. Suzuki et al.[21] reported that silk or nylon sutures may cause conjunctival inflammation and Langerhans cell migration into the cornea.

Koranyi et al.[17] compared 7/0 vicryl suture to fibrin glue in their study. They assessed postoperative patient complaints and operation time. They found that patient discomfort was less and operation time was shorter in fibrin glue group. In addition, they reported that the cost of one fibrin glue was equal to cost of five sutures and one fibrin glue can be used for 6–7 patients, making overall cost of surgery same for both the Group. We also had similar results and interpretation of cost–benefit analysis. The use of fibrin glue was associated with markedly reduced surgical time. Uy et al. also showed similar statistically significant reduction in mean operative time.[22] Postoperative pain was less in fibrin glue than those with suture group. Furthermore, in our study, pain lasted for less duration than those with suture group. Foreign body sensation present in most of the patients on 1^st postoperative day may be due to superficial keratectomy done during surgery. However, on subsequent days, patient in fibrin glue group was more comfortable than those in suture group. These observations are comparable to other studies evaluating these parameters.[23]

Attaching conjunctival autograft using autologous blood is a new approach, also known as “suture and glue free autologous graft.” This procedure has excellent results without any complications associated with sutures and glue. In Mitra et al.'s study [9] – a prospective, noncomparative, interventional case series conducted in India – 19 patients underwent graft fixation with autologous blood. The mean surgical time was 11 min, no grafts were lost, and none of the pterygium recurred in the study's 6 months of follow-up. In Sharma et al.'s study,[24] – out of 150 cases, who underwent graft fixation with autologous blood – recurrence during the follow-up period was seen in 4 patients –2.6%. In this study, there was one case of recurrence in 20 patients, i.e., 10%. This high percentage could be because of small size of group selected for surgery.

Conclusion

Fibrin glue and autologous blood both are good alternative to sutures in attaching conjunctival autograft in pterygium surgery. Sutures have inherent disadvantage of causing postoperative discomfort and other complications, whereas fibrin glue and autologous blood are safe. The use of fibrin glue as well as autologous blood can ease the surgical procedure, shorten operating time, and produce less postoperative discomfort. Attaching conjunctival autograft with autologous blood is technically difficult but can be learned with practice and is an excellent procedure bypassing the need for sutures and glue. The disadvantage with fibrin glue is its high cost; however, one vial is used for multiple patients reducing the overall cost of surgery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.