"> Best Limbal Stem Cell Surgery Doctors in Turkey

Best Limbal Stem Cell Surgery Doctors in Turkey

Limbal stem cell surgery or limbal stem cell transplant is a surgical treatment to address limbal stem cell deficiency (LSCD) and restore a corneal epithelial phenotype. Depending on the cell source, limbal transplant can be autologous or allogeneic. Many surgical techniques are defined according to the source of the stem cells and the carrier tissues used.

Limbal stem cell surgery has more recently been used to reconstruct the corneal surface, using autologous cells to eliminate the risk of rejecting ex vivo expanded bioengineered epithelial cells. A systematic examination of the eyelids, eyelashes, fornices and watery tears is mandatory before transplantation. Every effort is made to increase graft survival, optimize ocular surface health, and control inflammation.

What is Limbal Stem Cell?

Limbal stem cell, which is one of the stem cells found in the basal epithelial layer of the corneal limbus, is also known as corneal epithelial stem cells. These cells form the border between the sclera and the cornea. High proliferative potential, slow turnover rate, regeneration of the entire corneal epithelium, clonogenicity and expression of stem cell markers are among the characteristics of limbal stem cells.

Limbal stem cell proliferation, which has an important role in the protection of the cornea, acts as a barrier for conjunctival epithelial cells and normally prevents them from migrating to the corneal surface. The microenvironment of the limbus is thought to be important in maintaining the stem cells' stemness. Limbal stem cells are located in the basal epithelium in the limbal crypts of Vogt's palisades, which is located in the narrow zone between the cornea and the bulbar conjunctiva.

The loss of limbal stem cells, which is one of the adult stem cells located in the basal epithelial layer of the corneal limbus and helps to regenerate the corneal epithelium, results in corneal conjunctivalization and deterioration in visual function with pannus. Limbal stem cell deficiency is characterized by the repopulation of the corneal epithelium in the limbus and the loss or lack of stem cells vital for the barrier function of the limbus. When these stem cells are lost, the corneal epithelium cannot renew itself.

Which Area Considers Limbal Stem Cell Surgery?

Limbal stem cell deficiency is a complex pathology. The management of patients with LSCD depends on the extent of limbus involvement and whether the disease is unilateral or bilateral. For partial LSCD, mechanical debridement of the conjunctival epithelium from the corneal surface divides into stem cells from healthy limbal sectors.

This may be sufficient to restore the surface. Scraping of the conjunctival epithelium can be combined with amniotic membrane transplantation, which can make the ocular surface heal faster. An eye diseases clinic is applied for limbal stem cell surgery.

What is Limbal Stem Cell Surgery?

Limbal stem cell surgery is a surgical modality to regenerate or refill the ocular surface epithelium in an eye with a limbal stem cell deficiency. The transplanted tissue is obtained by lamellar dissection of the limbal and conjunctival tissue. Allograft transplants, typically cyclosporine, require lifelong immunosuppression.

Keratoprosthesis (artificial corneas) can also be used in cases of complete limbal stem cell deficiency and corneal opacity. Although the surgical technique is easier than limbal transplantation and the short-term visual results are very good, the risk of serious mid- and long-term complications is much higher with keratoprosthesis.

How is Limbal Stem Cell Surgery Performed?

Patients with LSCD have always been difficult to treat because corneal clarity cannot be restored with conventional corneal grafting alone. The goal of severe LSCD treatment is to reconstruct the anatomical and physiological environment of the ocular surface by reconstructing the cornea and conjunctival epithelium. The main goal before limbal stem cell surgery is to prepare the graft's new home and provide the best opportunity for its survival.

In particular, survival of limbal stem cells is partially dependent on the tear film and the limbal niche, which is affected by vascularity and innervation in the limbus. Many issues need to be addressed before stem cell transplantation, including optimizing and controlling the lids and tear film.

Limbal Stem Cell Surgery

Limbal epithelial stem cells are the primary source of corneal epithelial cell regeneration. Limbal stem cell deficiency may develop in traumatic, immunological or genetic diseases affecting the ocular surface. LSCD leads to corneal vascularization and opacification followed by conjunctivalization with vision loss.

In patients with ocular surface disease, many factors often affect the surface, and a slight abnormality that can be tolerated in a normal eye can compromise the outcome of the surgery. Therefore, a low threshold is recommended to treat adnexal abnormalities prior to stem cell transplantation. Preoperative systematic evaluation of the adnexa, including tear film status, eyelid position, lagophthalmos, and fornix depth is mandatory.

In general, the health and function of the eyelids, fornix, and tear film should be optimized prior to stem cell grafting. A source of goblet cells is required for conjunctival surface and fornix reconstruction in severe cases of conjunctival disease and symblepharon to provide the best chance of pituitary healing. The stem cells to be transplanted may be from a donor or a patient's healthy eye, in which case only part or at most half of the limbus can be removed.

What are the Advantages of Limbal Stem Cell Surgery?

The scleral-corneal limbus is a transition zone, a ring surrounding the cornea where the cornea and surrounding conjunctiva meet. This peripheral region of the cornea also contains corneal epithelial stem cells that, after growing at the limbus, migrate from the periphery to the center on the cornea and are eventually lost by desquamation.

There are a number of congenital or acquired factors that can severely damage the limbus and thus the stem cell population, causing a condition known as limbal stem cell deficiency syndrome. Limbal stem cell deficiency occurs when there is no longer a source of limbal stem cells for corneal epithelial cells. The result is invasion of conjunctival epithelial cells on the cornea.

This takes advantage of the limbus stopping to act as a barrier to keep the conjunctiva from growing. Enlargement of the conjunctival epithelium over the cornea causes vision loss, as well as epithelial adhesion problems, corneal erosion and ulcers, chronic inflammation, and abnormal blood vessel growth.

Limbal stem cell deficiency can be treated with eye drops when it is not yet fully developed. However, in severe cases, limbal stem cell transplantation is the best option. When the limbal stem cell deficiency is not fully developed yet and the cause is eliminated with medical treatment in the form of eye drops, the lesions may improve and become stable.

In cases where the integrity of the limbus is severely and severely damaged, regeneration is unlikely and medical treatments are ineffective. When this happens, the only effective treatment is surgery and involves transplanting stem cells again. In recent years, an alternative method for transplanting corneal epithelial stem cells has been developed, which involves taking a small sample of healthy limbus from a patient or a donor, growing it in the laboratory, and then transplanting the stem cells.

Post-Limbal Stem Cell Surgery Process

Care after limbal stem cell surgery is another important determinant of success. Any factor that destabilizes the ocular surface needs to be addressed. In addition, systemic and topical immunosuppressants are needed in all allograft recipients. In addition to pre- and post-operative care and the surgery itself, the etiology of LSCD also has an impact on the outcome. Inflammatory diseases such as Stevens-Johnson syndrome have the worst prognosis among the diseases that cause LSCD.



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