External Eye Resurfacing/Reconstruction

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Article initiated by:

Seyed-Farzad Mohammadi, MD MPH FICO

All contributors:

Vatinee Y. Bunya, MD, MSCE, Maria A. Woodward, MD, Seyed-Farzad Mohammadi, MD MPH FICO, Masako Chen, MD

Assigned editor:

Masako Chen, MD

Review:

Assigned status Update Pending

 by Masako Chen, MD on March 1, 2023.

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Contributing Editors:	add

Conjunctival limbal corneal allograft for External Eye Resurfacing

This is a complex surgical approach in the management of advanced ocular surface cicatrization through a single procedure conjunctival-limbal-corneal allograft. This procedure involves a lamellar corneolimbal keratoplasty, 360° limbal stem cell transfer (on a “bipedicle” conjunctival-corneal carrier), and conjunctival tissue transplantation. A single continuous sheet with two edges are sutured: donor corneal-limbal edge to the recipient’s scleral-limbal edge (avoiding overlying stem cell element of the donor tissue) and donor’s and recipient’s conjunctival edges. Fornices would be reconstructed if needed.

Context

Bilateral severe chemical or thermal injury is one of the most challenging to manage in ophthalmology. These injuries lead to bilateral ocular surface cicatrization from limbal stem cell deficiency, conjunctival loss, symblepharon formation and fornix obliteration, and corneal opacity and neovascularization.

Technique

It involves a single-procedure conjunctival-limbal-corneal allograft as follows (Figures 1, 2 and 3)

Bed preparation

Fibrovascular tissue and scarred conjunctiva are dissected centripetally from the cornea to the fornices. Bipolar cautery is applied to the bed for hemostasis and coagulation of remaining neovascularizations. Partial thickness corneolimbal trephination is carried out and followed by a deep and extensive anterior lamellar dissection to obtain a clear bed – ideally a bare Descemet’s membrane.

Donor preparation

Fresh globe is harvested along with bulbar conjunctiva (within 6 hours of death; to be transplanted within 24 hours post-mortem). Dissection is carried out anteriorly in the conjunctival-Tenon’s capsule plane undermining beyond limbal stem cell zone to anterior limbus. The conjunctiva is then kept rolled over the corneal surface and a limbal epithelial side trephination sparing the rolled conjunctiva is performed. The donor endothelium-Descemet’s membrane is scraped off next.

Suturing

The donor conjunctiva is maintained on the corneal top while suturing the donor’s corneal-limbal edge to the bed’s scleral-limbal edge. Conjunctiva is then rolled back and sutured to the recipient’s conjunctival free edge to reconstruct the fornices.

Note on post-op management

This should include long term systemic immunosupression.

Comments

Coster et al reported transplantation of the entire ocular surface in 1995 through different donor and recipient’s bed preparation and suturing technique. Currently recommended procedure for a bilateral condition is combined living-related conjunctival-limbal allograft plus kerato-limbal allograft followed by penetrating or lamellar keratoplasty or keratoprosthesis. Large-diameter lamellar keratoplasty (incorporating donor limbal tissue) has been advocated to restore corneal clarity as well as limbal stem cells in a single procedure. Deep anterior lamellar keratoplasty combined with conjunctival limbal autograft is suitable for unilateral cases.

The approach described here carries several theoretical advantages namely, a single-procedure for reconstitution of limbal and conjunctival stem cells and restoration of corneal clarity; it potentially transfers a whole eye limbal stem cell population on a solid conjunctival-corneal carrier (analogous to a bipedicle graft) which should maximize stem cell preservation intraoperatively and viability postoperatively. Lamellar approach circumvents the risk for endothelial rejection and at the same time necessitates an intact deep corneal stroma and endothelium. The technique is novel in two respects (Figures 1, 2 and 3)

1. Undermining the stem cell zone of the donor subconjunctivally to anterior limbus and rolling over the conjunctiva and limbal tissue prior to corneolimbal trephination. This yields a graft with two edges at donor conjunctiva and donor limbus;
2. Suturing of donor limbus to scleral-limbal recipient bed while donor conjunctival and limbal stem cell tissue are rolled over the donor cornea. This is followed by suturing the donor conjunctiva edge to recipient’s fornix conjunctiva.

It should be noted that the preparation of donor material is time consuming and suturing of the corneolimbal button to the recipient bed while keeping conjunctival-stem cell elements of the graft protected and away is challenging.

The indications might be quite limited but it can be considered as a last resort in the reconstruction of end-stage ocular surface. Theoretically, it involves a surgical stratagem in the evolution of ocular surface reconstruction techniques. Its viability should be formally studied in trials as there is a high risk for graft rejection.

Acknowledgement

The article is a reproduction of a peer-reviewed surgical technique paper by: Mehdi HosseiniTehrani, S-Farzad Mohammadi, Asou AliMahmoudi and Vandad Farhady in Iranian Journal of Ophthalmology 2012. It is noteworthy that the open publishing status of the work allows its reproduction, as long as the source is properly credited.