Eyeworld

MAY 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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May 2012 Tools & techniques Pterygium excision by John A. Hovanesian, M.D., and Andrew Behesnilian, B.S. Using conjunctival esides cataract surgery, ptery- gium excision is perhaps one of the most common surgical pro- cedures for the general ophthalmolo- gist. When performed as an excision alone, recurrence rates can be as high as 40% with aggressive and restrictive tissue replacing the primary pterygium. Past attempts at reducing recurrences with radiation or chemotherapy have re- sulted in long-term scleral melting and serious morbidity. The current standard for treating pterygium involves the use of conjunctival autografting, but amni- otic membrane is also being utilized in place of conjunctival grafts with suc- cess. The most cost-effective means of treating pterygium would be to use the patient's own conjunctival autograft secured in place with nylon sutures, however, there is increasing utilization of fibrin glue in these procedures that appears to reduce the inflammation caused by sutures while improving surgical efficiency. In this month's column, John A. B Hovanesian, M.D., describes an alter- native technique for pterygium excision that utilizes both amniotic membrane and a conjunctival autograft, both se- cured with fibrin glue. As with most of the articles in this column, it is not the only means or the simplest means of removing pterygium, but it does offer an alternative method that I believe you will find interesting. His step-by-step approach for working with fibrin glue will be valuable for any surgeon wishing to convert to this method of grafting. Richard Hoffman, M.D., Tools & techniques editor autograft and prophylactic subconjunctival placement of amniotic membrane Introduction Pterygium surgery using a conjuncti- val autograft is associated with re- currence in 5% of cases.1 These recurrences arise from the subcon- junctival Tenon's fascia surrounding the autograft. Amniotic membrane transplantation (AMT) has been used as an ocular surface graft in place of the conjunctival, but recur- rence rates are similar to eyes receiv- ing autografts.2 This is possibly because the amnion wears away from the ocular surface within 2-3 weeks of surgery and does not pro- vide its well-known antifibrotic ef- fects in the subconjunctival space from which recurrence is known to arise. We devised a method where AMT is used prophylactically as a biologic implant beneath the con- junctiva surrounding the autograft (and not beneath the autograft it- self). In this location, protected from the ocular surface, the AMT may provide more prolonged antifibrotic effects. A series of 40 pterygia under- going the procedure described below were followed a mean of 10 months (range 4-17) with no recurrences.3 Anesthesia Anesthesia is achieved with a peribulbar block of bupivicaine and lidocaine 1% with epinephrine. Sub- conjunctiva infiltration is also effec- tive for the procedure but in our experience allows more post-op dis- comfort. Watch this video on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.) Or view Dr. Hovanesian's comprehensive pterygium video at http://youtu.be/XGOot-us5MI Step-by-step surgery Fibrin tissue adhesive (Tisseel, Baxter Healthcare, Deerfield, Ill.) is recon- stituted according to the manufac- turer's instructions, but the solutions are not transferred to the supplied Duploject syringe. Instead, they are left in their original vials. The pterygium is excised along with a conservative (about 1 mm) margin of healthy conjunctiva, leav- ing a conjunctival defect and ex- posed bare sclera (Figure 1). Next, blunt Westcott scissors are used to create a potential space about 5 mm Figure 1. After pterygium excision, bare sclera is exposed. Note conjunctiva is shown in pink, with a yellow line on its epithelial side EW NEWS & OPINION 19 Figure 2. The pterygium has been excised and the autograft prepared and reflected onto the cornea at the superior limbus Figure 3. Freeze-dried human amniotic membrane is cut into a C-shaped graft Figure 4. The amniotic membrane is placed in the subconjunctival space surrounding the site of pterygium excision. The figure shows the loca- tion of graft in red around the eventual location of the conjunctival autograft Source (all): John A. Hovanesian, M.D. beneath the healthy conjunctiva on the three sides surrounding the exci- sion site. This potential space should be superficial to most of Tenon's fas- cia and to the medial rectus muscle and tendon. Cautery is used conser- vatively (see Pearls). From the supe- rior limbus, a thin conjunctival autograft is prepared, bringing along minimal Tenon's fascia. The graft should be sized similar to the con- junctival defect. At this point, the graft is left attached (Figure 2) at the limbus superiorly so it is not mis- ELP continued from page 17 come in the other eye prior to at- tempting this repair made the pa- tient functional and happy quickly. This gave me some latitude to try something in the right eye that might not have been a completely satisfactory resolution to her prob- lem if it were done first. As Dr. Whitman said, "It doesn't have to be a home run" because I had already hit the homer in the other eye; here I just needed to put the "runner on base" to score two runs. Since the results complemented the surgical outcome from her dominant left eye to give her good functionality, the sequence of events appears to have been an important component to achieving success here. EW Editors' note: The doctors mentioned have no financial interests related to this article. Contact information Safran: safran12@comcast.net placed during the following steps. Amniotic membrane preparation Freeze-dried human amniotic mem- brane tissue in its dry form is re- moved from its outer packaging but left in its inner packaging (foil on one side, clear plastic on the other). Using utility scissors, the AMT is cut through the packaging into a C- shaped graft (Figure 3) large enough to surround the conjunctival defect (Figure 4). This is placed to the side. continued on page 20

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