Estimated surgery time: 20 minutes.
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Primary Pterygium Before -
Primary Pterygium After
Insert a 15 mm solid blades Speculum (K1-5014 Katena), apply Epinephrine (1:1000) for hemostasis and 2% lidocaine gel (Astra Zeneca) for Topical Anesthesia P.S. Avoid peribulbar anesthesia which may distort the tissue plane
Place 7-0 Vicryl Traction Suture at the superior and inferior limbal sclera for adequate exposure and fixation of the globe
Excise pterygium head and body:
Use 0.12 forceps to pick up the conjunctiva in front of the semilunar fold (Fig. 1), and use scissors to make a conjunctival peritomy vertically. Then pick up the fibrovascular pterygium tissue toward the surgeon while using scissors to truncate it from the fornix. Without damaging the muscle, excise the Tenon from the sclera that is superior and inferior to the muscle. Remove the head and body of the pterygium from the cornea surface (Fig. 2).
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Figure 1 -
Figure 2
Apply MMC (0.02% to 0.04%):
Cut thin strips from a Weckcel's slant edges, soak them in the MMC solution, and apply approximately 2-3 sponges to subconjunctival fibrovascular tissue close to the fornix and above the tenon (Fig. 3). Before application, use a Q-tip to dry the bare sclera (Fig. 4). Then apply MMC strips for 2 min for mild, for 3 min for moderate, and 4 min for severe pterygium. Irrigate the contact surface with half a bottle of BSS after the incubation.
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Figure 3 -
Figure 4
Identify & Seal the gap between the Conjunctiva and Tenon:
Use two 0.12 forceps: one to grab the conjunctival edge and the other for the underlying Tenon, to evaluate the extent of the gap, especially at the caruncle (Fig. 5A). This gap allows reinvasion (hemiation) of the residual fibrovascular tissue, giving rise to recurrence if left open.
Use 8-0 Vicryl running sutures for primary pterygium and 9-0 Nylon for recurrent pterygium when "sealing the gap" from the superior to the inferior fornix. The natural traction of the Tenon posteriorly facilitates the conjinctiva bending away from the sclera, which will reform the shape of the caruncle (Fig 5B).
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Figure 5a -
Figure 5b
Transplant Cryopreserved Amnion Graft with Fibrin Glue:
nitrocellulose paper. Lay it on the bare sclera with the sticky/stromal surface facing down. Flip one half of the graft up to cover the other half revealing the bare sclera.
Apply the fibrinogen oily/cloudy solution to the bare sclera and/or the stromal side of the graft. Next, apply the thrombin/watery/clear solution to the same area.
Using two 0.12 forceps to flip back the graft to re-cover the bare sclera. Stretch and flatten the graft with two forceps at different areas for a total of 45 sec before final smoothening by a muscle hook. Repeat the above steps to the other half of the membrane. Trim any excess membrane and fibrin glue from around the defect and then tuck the graft underneath the conjunctival edge and seal the conjunctiva over the graft with fibrin glue placed in between (Fig. 6).
Always check the adhesion strength at the edge of the graft by 0.12 forceps. If the graft detaches, do "touch up" by applying fibrin glue to the unsecured areas.
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Figure 6
Additional Points:
- Minimize cauterization to blood vessels to avoid inflammation or ischemia.
- Engorged vessels are intrinsically normal and invariably regress.
- Avoid isolation of recti muscles by hook.
- It is not necessary to cover superficial corneal epithelial defect with the graft or a contact lens.
- Inject Kenalog in the surrounding host conjunctiva if it is too inflamed at the end of surgery.