1. Evaluation of a new technique for the preparation of endothelial grafts for Descemet’s membrane endothelial keratoplasty (DMEK)
World Cornea Congress VII
April , 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

2. 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

3. 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

4. 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

5. 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

6. 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.

7. 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

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

9. 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

10. 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.

11. 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

12. 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.

13. 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 ( )
Setareh Ziai, MD ( )
Abdulmajeed Aljaethen, MD ( )
Season Yeung, MD ( )
Joshua Teichman, MD, MPH ( )
Research Fellows
Mustafa Kapasi, MD ( )
Salina Teja, MD ( )
Ronan Conlon, MD ( )
Technologists
Sabrina Taylor, COMT
Emily Wong, COMT
Olga Plekhanova, COMT
Research
Melanie Lalonde, PhD
Gail Kayuk, BSc, ART
Annelise Saunders, LLB