Fornix Reconstruction Frequently Asked Questions
When is the best time to perform symblepharon lysis and fornix reconstruction?
In general, the surgery is best performed when the eye is quiet. Taking chemical burns as an example, symblepharon lysis and fornix reconstruction are already at the chronic stage when there is no ongoing active inflammation. For the same reason, it is better to wait for 6 months if the eye has failed from the first attempt of fornix reconstruction.
Why is it necessary to use intraoperative MMC?
If the preoperative evaluation does not reveal any inflammatory activity in the area of symblepharon and the patient’s underlying disease is not active, it is not necessary to use MMC at all. Unlike conjunctival autograft, cryopreserved amnion graft does not contain any live cells. Therefore, the healing depends on the migration of host cells into the membrane. The chronic inflammation in the host tissue surrounding the symblepharon, if not treated with MMC, may still retain its “malignant and abnormal” phenotype, and upon invasion into the membrane may continue to develop a cicatrix. That is why it is necessary to use MMC to suppress this abnormal phenotype and active inflammation in order to enhance the aesthetic outcome. It should be noted that MMC is applied subconjunctivally, but not onto the bare sclera, to avoid any side effects.
Why is it necessary to use conjunctival autograft or oral mucosal graft in severe cases?
In severe cases, there is a significant shortage of epithelial tissue between the lid margin and the limbus. The remaining conjunctival tissue is not sufficient to cover the tarsal conjunctiva, let alone to regenerate the entire fornix. For this reason, a small epithelium-containing tissue such as conjunctival autograft or oral mucosal graft is needed to provide the epithelial source. This free graft can help recover the entire region with the help of an amnion graft. The oral mucosal graft is more ideal to resurface the tarsal conjunctiva while the amnion graft is more ideal to resurface the bulbar conjunctiva.
Why is it necessary to place any anchoring sutures during fornix reconstruction?
After symblepharon lysis and the removal of any cicatrix, the recessed conjunctival tissue will readily collapse to contact the bare bulbar sclera, leading to recurrent formation of symblepharon. Therefore, it is important to anchor it to the palpebral tissue plane so that the subconjunctival fibrovascular tissue will point toward the orbital space instead. With the close apposition by the amnion graft to the epithelial edge, epithelial tissue, but not fibrovascular tissue, will grow onto the membrane.
How do you handle Limbal Stem Cell Deficiency (LSCD) in conjunction with symblepharon?
Before tackling the LSCD issue, it is important to control and correct any scarring and inflammation related to the symblepharon. Therefore, in general, it is better to perform symblepharon lysis and fornix reconstruction before treatment for LSCD because there will be a more favorable environment to treat LSCD when the eye is quiet. For some cases, symblepharon is contiguous with the pannus extending onto the corneal surface in the region where there is LSCD. If LSCD is partial, i.e., the other limbal region still contains healthy limbal stem cells, transplantation of cryopreserved amnion graft can be extended to cover the corneal surface after superficial keratectomy to remove the pannus. Frequently, this approach will also result in restoration of the limbus in this region. However, if LSCD is diffuse and total, it is best not to remove the pannus from the corneal surface during the symblepharon lysis and fornix reconstruction. The LSCD is best left to the second stage when transplantation of limbal stem cells by either conjunctival limbal autograft (from the fellow eye) or keratolimbal allograft (from the cadaver) is contemplated.
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