Graft Detachment Rate in DSEK/DSAEK After Same-Day Complete Air Removal Roy E Lehman MD*, Samuel F Fulcher MD** Baylor Scott and White Hospital and Clinic* Central Texas Veterans Heath Care System** The authors have no financial interests to disclose This work was supported by the Baylor Scott and White Health Care System and the Central Texas Veterans Health Care System

Purpose The purpose of our investigation is to determine and report the rate of graft detachment following DSEK/DSAEK surgery after complete same day air removal by a single surgeon over a 10 year period. Secondary measures include rates of primary graft failure, late endothelial graft failure, rejection events, and steroid induced ocular hypertension.

Background Corneal graft detachment is one of the most frequent complications experienced after DSAEK surgery (Price & Price, 2006). Rates of graft detachment after DSAEK have been reported to range from 0- 82%, with an overall average of 14% as reported by Lee et al in 2009. DSAEK detachment rates have been reported to be higher in the learning curve of beginning surgeons, but then decline with gained experience. Various methods have been utilized to lower graft detachment rates, including the use of a spatula to sweep fluid from the interface after a complete air fill as reported by Terry et al (Terry, Shamie, Chen, Hoar, & Friend, 2008).

Background In 2006 Price et al reported that mid-peripheral corneal venting incisions were useful to remove interface fluid to reduce detachment rates and were helpful for graft positioning and centration from the stromal side of the donor tissue (Price & Price, 2006). We have utilized venting incisions in our series since 2006 to assist with interface fluid removal as performed by a single surgeon (SFF). Our goal was to determine and report the rate of DSAEK graft detachment over a 10 year period, with the use of venting incisions combined with complete air removal one hour after surgery and to compare this rate with reported detachment rates in the literature.

Methods A retrospective chart review was performed to identify all patients at our institutions that underwent DSEK/DSAEK by a single surgeon from January 2005 through December 2014. A total of 313 cases were identified. Two cases were excluded from the analysis because of intraoperative complications early in the learning curve which led to conversion to PKP. A third case was excluded because air was left in the eye due to a pre-existing sectoral iridectomy, which reduced the risk of air bubble pupillary block glaucoma. A total of 310 cases were thus included for analysis. Mid-peripheral corneal incisions were implemented in 2006 to assist with interface fluid removal. All surgeries involved the use of a complete air fill, which was removed one hour after placement prior to patient discharge. Descriptive statistical analysis was used to report the rates of graft detachment, primary graft failure, late endothelial graft failure, rejection events, and steroid induced ocular hypertension.

Outcome Definitions Graft Detachment: Any complete or extensive partial detachment of the graft which required rebubbling. Partial detachments that resolved spontaneously without rebubbling were excluded. Primary Graft Failure: Failure of the graft to clear within 30 days after surgery. Late Endothelial Graft Failure: Late graft failure as evidenced by endothelial failure after initial surgical success with a clear attached graft. Graft Rejection Event: Any episode of endothelial rejection as evidenced by anterior chamber cell and flare, keratic precipitates, and resultant graft dysfunction. Steroid Induced Ocular Hypertension: An elevation of intraocular pressure which occurred at any time in the post operative course which led to steroid drop adjustment or institution of ocular anti-hypertensive agents.

Results Year Total DSEK/DSAEK Detachments % Detachment 2005 13 3 23.08% 2006 30 2 6.67% 2007 44 6.82% 2008 51 4 7.84% 2009 49 1 2.04% 2010 5 9.80% 2011 42 2.38% 2012 19 0% 2013 2014 6

Results Total graft detachment rate: 6% One graft detachment in the last 79 cases (1.27%)

Results

Discussion The overall DSAEK graft detachment rate of 6% as reported in our retrospective study is comparable to the experiences of others with a higher initial rate that rapidly declines with surgeon experience. The graft detachment rate of 1.27% over the last 79 cases would seem to indicate that leaving a residual air bubble in the anterior chamber is not necessary to achieve excellent graft attachment rates. The 19% rate of ocular hypertension with postoperative steroid use is in line with the experience of others. There were no primary graft failures in this series, and the late endothelial failure rate of 8% over a ten year follow up period, and rate of rejection events of 11% are similar to those reported elsewhere. The earliest graft failure occurred one year after surgery.

Conclusion Low rates of DSAEK/DSEK graft detachment are achievable with complete same day air removal. Factors that contribute to low graft detachment rates cannot be definitively identified in our retrospective series. We hypothesize that complete interface fluid removal combined with complete air removal and prompt restoration of the anterior chamber assists the recovery of endothelial function, and may be helpful in lowering graft detachment rates. Same day air removal would lower the risk of pupillary block glaucoma and would reduce the risk of air toxicity to the corneal endothelium.

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