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Conjunctival Limbal Autograft 1
Key Concepts
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Conjunctival limbal autograft (CLAU) represents the first surgical option for unilateral limbal stem cell deficiency, given the good long-term survival results and visual outcomes.
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The most important risk factors contributing to graft failure are severe dry eye, chronic inflammation, and associated adnexal abnormalities.
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Although there is potential risk to donor eyes, no serious complications have been reported in healthy donor eyes when appropriate precautions are taken.
Acknowledgment
Authors thank Drs. Ali R. Djalilian and Alireza Baradaran-Rafii for their contribution to this chapter.
Introduction
Limbal epithelial stem cells (LESCs) are located in the palisades of Vogt at the limbus, and they interact closely in their niche with a specialized extracellular matrix and other cells, including mesenchymal stem cells. Together, they contribute to the unique properties of the cornea, such as avascularity, clarity, and immune privilege. With an injury to the LESCs or their highly regulated microenvironment, limbal stem cell deficiency (LSCD) develops. Clinical manifestations include corneal conjunctivalization, poor corneal epithelialization, persistent epithelial defects, stromal scarring, severe visual loss, chronic pain, and neovascularization of the cornea. Management is based on severity (partial vs. total), laterality (unilateral vs. bilateral), and whether there is conjunctival involvement. ,
Autologous limbal transplantation was first described by Strampelli in 1960 and subsequently by Barraquer in 1964. Kenyon and Tseng reported on the use of autografts of conjunctiva and limbus for management of diffuse unilateral limbal deficiency in 1989. Conjunctival limbal autograft (CLAU) was described within a classification system for epithelial transplantation proposed by Holland and Schwartz in 1996. Since then, there have been many reports describing the use of CLAU in management of unilateral ocular surface diseases.
Indications and Patient Selection
CLAU, as an ocular surface stem cell transplantation (OSST), is a procedure in which limbal tissue attached to a conjunctival carrier is transplanted from the healthy eye of a patient to the contralateral stem cell-deficient eye. Its primary advantage over all allograft procedures is that no immunosuppression is required. It is the procedure of choice for unilateral total LSCD. In addition to limbal tissue, conjunctival tissue is also transplanted, which makes CLAU particularly effective at treating patients with conjunctival scarring or inflammation.
A major concern of CLAU is the potential risk to the donor eye. In fact, in vitro studies have shown that full-thickness excision of sectoral areas of limbal tissue can compromise the donor surface. Clinically, this has not been observed. To prevent inducing stem cell deficiency in donor eyes, surgeons should be conservative in patient selection and exclude those with suspected ocular surface pathology or any exposure to risk factors, such as long-term contact lens wear or previous surgery. In addition, conservative harvesting of limbal tissue is warranted.
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