World Cornea Congress, San Diego, CA Mini-Simple Limbal Epithelial Transplantation (Mini-SLET) Technique for the Treatment of Pterygium Erick Hernandez-Bogantes1, MD, Alejandro Navas1, MD, MSc, Enrique O. Graue Hernandez1, MD, MSc, Arturo Ramirez-Miranda1, MD, Guillermo Amescua2, MD, Alejandro Lichtinger1, MD 1Department of Cornea and Refractive Surgery. Instituto de Oftalmologia ‘Fundacion Conde de Valenciana’, Mexico D.F., Mexico 2Department of Ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, Miami, FL, USA World Cornea Congress, San Diego, CA April, 2015

None of the authors have any financial interest to disclose

Introduction The most common surgical techniques for pterygium removal includes leaving bare sclera, using a conjunctival or conjunctival-limbal autograft, coverage with amniotic membrane (AM) or the use of adjuncts like mitomycin C Recurrence rates among these techniques varies widely with reports between 3.3% and 40.9% Advantages of using an AM are: Improvement of epithelial cell migration and differentiation Inhibition of angiogenesis Inhibition of cicatrization The possibility to cover a large area without the need of harvesting healthy conjunctiva

Purpose Our innovative technique describes the use of an AM graft to cover the bare sclera area combined with a small autologous simple limbal epithelial transplant (Mini-SLET) to provide stem cells at the limbal area.

Surgical Technique A, Nasal, temporal or bilateral pterygium are adequate candidates. B, Resection of pterygium with conventional techniques leaving bare sclera. C, Placement of amniotic membrane and resection of 2x2 mm of epithelial limbal stem cells. D, Slicing of epithelial limbal strip into 6-8 pieces. E, Alignment of small limbal transplants close to the limbal area over the amniotic membrane. F, Placement of a second amniotic membrane covering the pieces. G, Placement of a soft contact lens.

Posoperative day 1, notice the epithelial stem cells in place under the covering amniotic membrane

Demographic, Preoperative and Postoperative Outcomes of Patients that Underwent mini-SLET Gender Age Eye Clinical Grading Site of pterygium Recurrence Complications 1 Male 34 OD T2 Bilateral None 2 82 Temporal 3 Female 46 OS T1 Nasal 4 67 T3 5 57 Pyogenic granuloma 6 26 7 70 8 31 9 49 OU

Preoperative and Postoperative Clinical Photographs of 2 Eyes that Underwent mini-SLET A, preoperative photograph of a 47-year-old male carpenter (case 9) with a history of bilateral pterygium. B, 1 day after the surgery. C, After 1 week the amniotic membrane is fully attached to the scleral surface, there is no epithelial defect and the limbal epithelial pieces are visible and in place.. D, 1 month. E, 3 months. F, Preoperative photograph of a 26-year-old student (case 6) with bilateral pterygium, the mini-SLET was performed in the temporal lesion. G, 1 day after the surgery. H, 1 week. I, 1 month. J, 3 months.

Discussion Sangwan et al(4) described simple limbal epithelial transplantation as a technique for the treatment of stem cell deficiency. Inspired by this technique, we decided to combine the use of an AM graft which serves as an ideal substrate to support the growth of epithelial progenitor cells. We hypothesize that the addition of the stem cells contained in the mini-SLET pieces could improve the cosmetic outcomes and reduce recurrence rates.

Discussion For patients with primary pterygium the justification of additional expense of AM might not be justified, however, patients with limited amount of conjunctiva, the need of future surgeries or patients with previous multiple surgeries, the mini-SLET technique might be helpful.

Conclusions We believe that the mini-SLET procedure is reproducible and an easy to learn surgical technique. It requires much less tissue than conventional conjunctival autografts. While having no early signs of recurrence, the mini-SLET offers the advantages of epithelial stem cells, which in a long-term may reduce the rate of recurrence significantly.

References Cano-Parra J, Diaz-Llopis M, Maldonado MJ, Vila E, Menezo JL. Prospective trial of intraoperative mitomycin C in the treatment of primary pterygium. The British journal of ophthalmology. 1995 May;79(5):439-41. Demirok A, Simsek S, Cinal A, Yasar T. Intraoperative application of mitomycin C in the surgical treatment of pterygium. European journal of ophthalmology. 1998 Jul-Sep;8(3):153-6. Ozer A, Yildirim N, Erol N, Yurdakul S. Long-term results of bare sclera, limbal-conjunctival autograft and amniotic membrane graft techniques in primary pterygium excisions. Ophthalmologica Journal international d'ophtalmologie International journal of ophthalmology Zeitschrift fur Augenheilkunde. 2009;223(4):269-73. Sangwan VS, Basu S, MacNeil S, Balasubramanian D. Simple limbal epithelial transplantation (SLET): a novel surgical technique for the treatment of unilateral limbal stem cell deficiency. The British journal of ophthalmology. 2012 Jul;96(7):931-4. Amescua G, Atallah M, Nikpoor N, Galor A, Perez VL. Modified simple limbal epithelial transplantation using cryopreserved amniotic membrane for unilateral limbal stem cell deficiency. American journal of ophthalmology. 2014 Sep;158(3):469-75.