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Larger graft size linked to better DSAEK outcomes
A modified technique prepares a larger graft without compromising the anterior segment.
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Inserting a larger endothelial graft with a donor trephine size of 9 mm or 9.5 mm was associated with a higher rate of graft success, according to a large study of patients who underwent Descemet’s stripping automated endothelial keratoplasty.
Vito Romano, MD, a senior cornea fellow at St. Paul’s Eye Unit, Royal Liverpool University Hospital, U.K., and colleagues decided to undertake the study, which appeared in the British Journal of Ophthalmology, because they observed that graft failure with DSAEK was associated with graft trephine size.
“We also noticed that on slit lamp biomicroscopy, larger grafts were away from the limbus, and on anterior segment OCT, the size of the graft was smaller in the eye than on the trephine block,” Romano said.
Study results
Of the 131 study patients, 64% had Fuchs’ endothelial dystrophy and 36% had pseudophakic bullous keratopathy. Patients were divided into three groups based on the size of the donor trephine: less than 9 mm (8.5 mm to 8.75 mm), 9 mm and 9.5 mm.
Results of at least 1 year found no appreciable differences among the three groups between preoperative and postoperative best corrected visual acuity; 80% of patients achieved a BCVA of 20/40 or better.
“However, graft survival was significantly better using larger grafts (9 mm and 9.5 mm),” Romano told Ocular Surgery News.
Eleven patients (8.4%) developed endothelial graft failure, with failure rates diminishing with smaller to larger grafts, from 17.86% for five small grafts, to 6.56% for four 9-mm grafts, to 3.64% for two large grafts.
Despite a longer follow-up for patients with grafts smaller than 9 mm, there was no significant time difference to failure: an average of 648 days for the smaller grafts, 604 days for the 9-mm grafts and 352 days for the 9.5-mm grafts.
Besides graft size, smaller donor endothelial cell density was notably associated with graft failure. But postmortem time, donor age, presence or absence of risk factors, complications and comorbidity did not influence failure rates.
A surgical technique modification, as described in Cornea, “has enabled us to achieve a large (9.5 mm) but ultrathin (less than 100 µm) posterior lamellar graft,” Romano said. “It has become apparent that the recovery of vision is quicker with the large ultrathin graft.”
Image: Romano V
Revised surgical technique
For the revised technique, the peripheral dissection “is very important in preparation of the graft,” Romano said. “In addition, increasing anterior chamber pressure and corneal drying help to achieve an ultrathin DSAEK. This plays a crucial role in the recovery of vision.”
The ease and centration of introducing a 9.5-mm graft in the anterior chamber came as a surprise to Romano. “In our experience, larger grafts unfold and center with minimal manipulation,” he said.
Two study patients, one with a 9-mm graft and the other with a 9.5-mm graft, had reversible graft rejection, without the development of graft failure, at the 2-year follow-up.
To increase the likelihood of success with the procedure, Romano recommended starting manual dissection of the residual peripheral anterior lamella in the mid-periphery, using a crescent blade. And with a large ultrathin DSAEK, “you will notice the difference.”
By relying on a 9.5-mm graft, “we transplant 10% to 20% more endothelial cells, so we expect a longer graft survival,” Romano said.
As these patients continue to be monitored, the authors are noticing faster visual recovery. “We are also looking at 5-year survival of larger grafts in a national cohort of patients,” Romano said. – by Bob Kronemyer
- References:
- Romano V, et al. Br J Ophthalmol. 2015;doi:10.1136/bjophthalmol-2014-305648.
- Romano V, et al. Cornea. 2015;doi10.1097/ICO.0000000000000451.
- For more information:
- Vito Romano, MD, can be reached at St. Paul’s Eye Unit, Royal Liverpool University Hospital, 8Z Link, Prescot St., Liverpool L7 8XP, UK; email: vito.romano@gmail.com.
Disclosure: Romano reports no relevant financial disclosures.