title: The S-stamp in Descemet Membrane Endothelial Keratoplasty Safely Eliminates Upside-down Graft Implantation.
abstract: OBJECTIVE
  To present 6-month clinical outcomes from a series of 165 consecutive Descemet membrane endothelial keratoplasty (DMEK) procedures before and after the introduction of a novel stromal-sided S-stamp preparation technique that has decreased the incidence of iatrogenic primary graft failure by eliminating upside-down grafts.
  
  
  METHODS
  Retrospective nonrandomized comparative case series.
  
  
  METHODS
  We included 165 consecutive eyes that had undergone DMEK surgery for Fuchs' or pseudophakic bullous keratopathy. These cases were divided into 2 cohorts: the first cohort comprised 31 cases that used unstamped tissue before the S-stamp was introduced, and the second cohort comprised 133 cases after the S-stamp was incorporated into the standardized technique. A single unstamped DMEK case was performed after the introduction of the S-stamp for a total of 32 unstamped cases.
  
  
  METHODS
  Donor materials were prepared at a single eye bank using a standardized technique, which subsequently incorporated the addition of a dry ink gentian violet S-stamp to the stromal side of Descemet membrane. All surgeries were performed at a single clinical site by 5 surgeons (2 attending surgeons and 3 fellows). Two of the 165 DMEK cases were performed for pseudophakic bullous keratopathy (2 cases, 1 in each cohort), and the remaining cases were for Fuchs' endothelial dystrophy. Primary outcome measures were assessed at 6 months and maintained in a prospective institutional review board-approved study.
  
  
  METHODS
  We analyzed the 6-month endothelial cell density, incidence of iatrogenic primary graft failure, upside-down graft implantation, and rebubble events.
  
  
  RESULTS
  The S-stamp eliminated upside-down graft implantations (0/133 S-stamped vs 3/32 unstamped) and did not significantly alter 6-month endothelial cell loss (31±17% S-stamped vs 29±14% unstamped; P = 0.62) or frequency of rebubble (17/133 S-stamped vs 1/32 unstamped; P = 0.20).
  
  
  CONCLUSIONS
  The incorporation of a stromal-sided S-stamp eliminates iatrogenic primary graft failure owing to upside-down implantation of DMEK grafts, without adversely affecting early postoperative complications or 6-month endothelial cell loss.
authors.affiliation: Massachusetts Eye and Ear Infirmary, Boston, Massachusetts; Devers Eye Institute, Portland, Oregon. Electronic address: peterbveldman@gmail.com.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Veldman
authors.affiliation: Lions VisionGift, Portland, Oregon.
authors.forename: Philip K
authors.initials: PK
authors.lastname: Dye
authors.affiliation: Lions VisionGift, Portland, Oregon.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Holiman
authors.affiliation: Lions VisionGift, Portland, Oregon.
authors.forename: Zachary M
authors.initials: ZM
authors.lastname: Mayko
authors.affiliation: Devers Eye Institute, Portland, Oregon.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Sáles
authors.affiliation: Devers Eye Institute, Portland, Oregon.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Straiko
authors.affiliation: Lions VisionGift, Portland, Oregon.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Galloway
authors.affiliation: Devers Eye Institute, Portland, Oregon.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Terry
mesh_terms: D003315:Cornea / Q000473:pathology* / Q000601:surgery; D057111:Descemet Stripping Endothelial Keratoplasty / Q000379:methods*; D005500:Follow-Up Studies; D005642:Fuchs' Endothelial Dystrophy / Q000175:diagnosis / Q000601:surgery*; D006084:Graft Rejection / Q000517:prevention & control*; D006085:Graft Survival; D006801:Humans; D012189:Retrospective Studies; D013997:Time Factors; D020858:Tissue and Organ Harvesting / Q000379:methods*; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome