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Challenges of pterygium surgery overcome using bare sclera technique with MMC
MMC placement within the subconjunctival tissue minimizes recurrence, avoids scleral melt and achieves good cosmetic results.
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The use of the bare sclera technique with 0.1 cc of mitomycin C 0.02% placed within the subconjunctival tissue can be an effective pterygium excision procedure, William B. Trattler, MD, said at OSN New York 2014.
With the more popular use of conjunctival autografts and amniotic grafts, the use of the bare sclera technique has fallen out of favor over time due to the increased risk of recurrence, Trattler said. In addition, cases of scleral melt have been reported when sponges soaked with MMC 0.02% have been placed over the bare sclera. However, by placing MMC within the subconjunctival tissue rather than against the scleral bed, recurrence is minimized, scleral melt is avoided, and a good cosmetic result is achieved, he said.
William B. Trattler
“The key to the bare sclera technique is the use of mitomycin C,” Trattler said. “If you do bare sclera without mitomycin C, the risk of recurrence goes way up, but with mitomycin C, the risk of recurrence is very low. … And the risk for scleral melt can be avoided if you place that mitomycin within the subconjunctival tissue rather than against bare sclera.”
Anduze technique
Trattler uses a modification of the Anduze MMC application technique, with 0.1 cc of 0.02% MMC injected into the subconjunctival tissue that remains after removing the pterygium (Figures 1 and 2).
First, the pterygium is injected with a small amount of 2% lidocaine with epinephrine to help elevate the subconjunctival tissue. An incision is then made at the limbus. The pterygium head on the cornea is elevated with a 30-gauge needle or a blunt instrument, which is then used to rip or slide off the material. A diamond burr can be used afterward to polish the cornea.
Figure 1. Fibrovascular tissue removed before injection of MMC.
Figure 2. Injection of 0.1 cc of 0.02% MMC.
Images:Trattler WB
A small area of conjunctival defect remains, and subconjunctival tissue can be grasped, pulled forward and lifted before safely excising the subconjunctival material to reduce the risk of recurrence. The next step is the injection of 0.1 cc of MMC 0.02% into the remaining subconjunctival tissue. The tissue is then rinsed with balanced salt solution.
“It’s a 7- to 10-minute surgery. It’s very simple and safe, and it works very well,” Trattler said.
Follow-up
Postoperatively, Trattler optimizes the ocular surface by placing a silicone punctal plug to raise the tear film and avoid dry eye, and then applies topical steroids and occasionally topical cyclosporine.
“I recommend a strong steroid,” Trattler said. “The risk for recurrence has been shown to be related to inflammation.”
In the past, MMC was placed on the bare sclera during pterygium surgery, leading to avascularity and increased risk of corneal melt.
By avoiding the placement of MMC onto the scleral bed and avoiding or minimizing cautery, which also contributes to avascularity, the risk of developing scleral melt is significantly reduced, Trattler said.
Trattler said that he adopted this technique approximately 5 years ago and will be reporting results from a retrospective review at the American Society of Cataract and Refractive Surgery meeting. – by Kristie L. Kahl
For more information:
William B. Trattler, MD, can be reached at 8940 N. Kendall Drive, #400, Miami, FL 33176; email: wtrattler@gmail.com.Disclosure: Trattler reports he is a consultant for AMO, Allergan, Bausch + Lomb, CXLO and Oculus; a speaker for Oculus, AMO, Bausch + Lomb and Allergan; and has a financial interest in CXLO and CurveRight.