title: Endothelium-in versus endothelium-out for Descemet membrane endothelial keratoplasty graft preparation and implantation.
abstract: OBJECTIVE
  To evaluate the difference between endothelium-in and endothelium-out for Descemet membrane endothelial keratoplasty (DMEK) preparation and implantation using injection method.
  
  
  METHODS
  The study was a randomized, comparative, institutional, laboratory investigation. Eighteen human donor corneas were included. A total of 9.5 mm DMEK grafts were stripped and restored on the corneal base with a hinge and preserved in the deswelling medium. The grafts were detached from the hinge and either manually tri-folded with the endothelium on the inside, or allowed to spontaneously roll in phosphate-buffered saline (PBS) with endothelium outwards. The corneas were mounted on an artificial anterior chamber (AAC) and four incisions made using a 15° eye knife for the side ports and slit knife to create a 3.0 mm incision for delivery of the graft into the AAC. The grafts with endothelium-in (endo-in) were pulled into a cartridge, whereas those with endothelium-out (endo-out) were aspirated using a modified Jones tube. Both were delivered using an injection method. Central and peripheral endothelial cell density (pre- and post-delivery and after removal), time of preparation and unfolding were measured.
  
  
  RESULTS
  Endothelial cell loss postimplantation was 10.53% (±2.82) with endo-in (n = 9) compared to 7.56% (±14.74) with endo-out (n = 9) (p > 0.05). Preparation and unfolding time was 4.43 min (±3.43) and 0.96 min (±1.10) for endo-in compared to 1.68 min (±0.57) and 4.92 min (±4.21) for endo-out. A statistical significance between endo-in and endo-out for loading (p = 0.04) and unfolding (p = 0.023) time was observed.
  
  
  CONCLUSIONS
  Descemet membrane endothelial keratoplasty tissues can be tri-folded (endo-in) with no significantly less cell loss as compared to endo-out. Spontaneous unfolding of endo-in may reduce overall time and surgical manipulation.
authors.affiliation: International Center for Ocular Physiopathology, The Veneto Eye Bank Foundation, Venice, Italy.
authors.forename: Mohit
authors.initials: M
authors.lastname: Parekh
authors.affiliation: International Center for Ocular Physiopathology, The Veneto Eye Bank Foundation, Venice, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ruzza
authors.affiliation: International Center for Ocular Physiopathology, The Veneto Eye Bank Foundation, Venice, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferrari
authors.affiliation: Institue of Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK.|St Paul's Eye Unit, Department of Eye and Vision Science, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Sajjad
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: Institue of Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK.|St Paul's Eye Unit, Department of Eye and Vision Science, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kaye
authors.affiliation: International Center for Ocular Physiopathology, The Veneto Eye Bank Foundation, Venice, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Ponzin
authors.affiliation: Institue of Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK.|St Paul's Eye Unit, Department of Eye and Vision Science, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Vito
authors.initials: V
authors.lastname: Romano
mesh_terms: D000368:Aged; D002452:Cell Count; D003886:Descemet Membrane / Q000473:pathology / Q000601:surgery*; D057111:Descemet Stripping Endothelial Keratoplasty / Q000379:methods; D004728:Endothelium, Corneal / Q000166:cytology / Q000637:transplantation*; D005260:Female; D005642:Fuchs' Endothelial Dystrophy / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D008297:Male; D009924:Organ Culture Techniques / Q000379:methods*; D014019:Tissue Donors; D014792:Visual Acuity
keywords: Descemet membrane endothelial keratoplasty; endothelium-in; endothelium-out; preparation; transplantation