Evaluation of a new technique for the preparation of endothelial grafts for Descemet’s membrane endothelial keratoplasty (DMEK) World Cornea Congress VII April 15 - 17 2015, San Diego CA Ashley Brissette, MD; Ronan Conlon, MD; Joshua C Teichman, MD, MPH, FRCSC; Season Yeung, MD; Setareh Ziai MD, FRCSC; Kashif Baig, MD, MBA, FRCSC University of Ottawa Eye Institute, Ottawa, Canada

Financial Disclosures Drs. Brissette, Teichman, Yeung, Ziai, Conlon have no financial relationships to disclose. Dr. Baig has the following relationships: Financial Interest/ Affiliation Name of Company(s) Grant/Research Support Allergan, Bausch & Lomb, Merck, Moria Employment/Honoraria/Consulting Fees/Travel Expenses Alcon, Allergan, Bausch & Lomb, Labtician Major Stock Shareholder None Member: Advisory Panel, Standing Committee, Board of Directors Allergan, Bausch & Lomb Other Financial or Material Interest

Introduction A critical step in DMEK surgery is preparation of the donor Descemet’s membrane while minimizing trauma to endothelial cells Donor tissue is prone to tears and endothelial cell loss A new method for preparing endothelial grafts for DMEK was proposed by Muraine et al. 2013 Involves a Muraine punch℗ and artificial anterior chamber Boasts superior endothelial cell density post DMEK using this technique

Muraine Technique Step 1: Using the Muraine℗ punch- trephine donor Descemet’s membrane with 2 protected hinges left intact Step 2: Mount donor cornea onto artificial chamber endothelial side up, seal and inflate Muraine Punch

Artificial anterior chamber Muraine Technique Step 3: stain with Tryptan Blue and peel peripheral Descemet’s Step 4: create delamination plane and hydrodissect Descemet’s with 27-G cannula Artificial anterior chamber

Purpose To compare a new method for harvesting endothelial donor grafts for DMEK, known as the Muraine technique, to the current SCUBA peeling technique in donor research eyes.

Prospective ex vivo investigation Methods Prospective ex vivo investigation 20 donor corneas prepared for DMEK using the Muraine Technique 10 by a corneal surgeon and 10 by a corneal clinical fellow 20 donor corneas prepared for DMEK using the SCUBA Peeling Technique

Outcomes Primary: Time to prepare the endothelial grafts Number of tears Secondary: Qualitative pattern of endothelial cell staining compared between the two techniques

Results By comparing the two techniques Time to prepare graft Graft tears Pattern of endothelial cell staining Muraine Fellow: 543 ±44 Surgeon: 359 ±84 Fellow: 3 Surgeon: 2 Mild diffuse staining: 2 Scuba Fellow: 523 ±58 Surgeon: 301 ±85 Fellow: 0 Surgeon: 0 Moderate peripheral staining: 2 By comparing the two techniques There were 6 corneas with no cell loss patterns, 2 tears, and 2 corneas with mild diffuse punctate changes in the Muraine group. In the scuba group there were 8 with no cell loss, and 2 moderate peripheral punctate changes. SCUBA peeling was faster than the Muraine technique when both were used to prepare an endothelial donor graft, however the results were not statistically significant. Time to prepare grafts: p= 0.46 Tears between grafts: p= 0.047

Pattern of endothelial cell staining Digital pictures taken through the operating microscope before and after donor graft preparation. Patterns defined and rated as: central, peripheral, or diffuse; and mild, moderate, or severe. A: Pre-stripping- Muraine technique B: Post-stripping- Muraine technique C: Pre-stripping- SCUBA technique D: Post-stripping- Muraine technique Three independent investigators evaluated the pattern of staining.

Results Primary Outcome Time to prepare donor graft for DMEK: Difference was NOT statistically significant: p= 0.46 Graft tears during preparation of donor tissue: More tears in grafts prepared in the Muraine group: p = 0.047 Secondary Outcomes: Pattern of endothelial cell staining: Diffuse pattern using the Muraine technique, peripheral pattern using the SCUBA technique

Conclusions Given the incidence of graft tears in the Muraine group, as well as the need for specialized equipment (the Muraine punch), we conclude that the SCUBA technique may be superior for the preparation of endothelial donor grafts for DMEK. With further refinement, this new technique has the potential to be a reliable alternative method.

Cornea, Anterior Segment, and Refractive Surgery Team at the University of Ottawa Eye Institute Attendings Kashif Baig, MD, MBA Bruce Jackson, MD George Mintsioulis, MD Setareh Ziai, MD Clinical Fellows Samer Abuswider, MD (2009-11) Setareh Ziai, MD (2011-12) Abdulmajeed Aljaethen, MD (2012-13) Season Yeung, MD (2013-14) Joshua Teichman, MD, MPH (2013-14) Research Fellows Mustafa Kapasi, MD (2011-12) Salina Teja, MD (2012-13) Ronan Conlon, MD (2013-14) Technologists Sabrina Taylor, COMT Emily Wong, COMT Olga Plekhanova, COMT Research Melanie Lalonde, PhD Gail Kayuk, BSc, ART Annelise Saunders, LLB