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Ultra-thin DSAEK delivers effective method of re-grafting
Compared with secondary DMEK after failed primary DMEK, the technique has a lower risk of complications and comparable long-term visual outcomes.
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Ultra-thin Descemet’s stripping automated endothelial keratoplasty is a viable option to deal with failed Descemet’s membrane endothelial keratoplasty grafts, according to one surgeon.
“Potentially we could try another DMEK, but with UT-DSAEK we’re playing safe because the risk of complications, such as another failure or graft detachment, is lower,” Massimo Busin, MD, told Ocular Surgery News.
In a study published in the British Journal of Ophthalmology, Busin and colleagues evaluated the results of UT-DSAEK as a secondary procedure in 21 patients with primary DMEK graft failure. The secondary procedures, mostly referred cases, were performed at Villa Igea Hospital in Forlì, Italy, between 2013 and 2017.
Three of these eyes had undergone DMEK due to pseudophakic bullous keratopathy and 18 due to Fuchs’ endothelial dystrophy. One of the Fuchs’ eyes had undergone DMEK combined with phacoemulsification and IOL implantation.
“In all these patients, the cornea had remained edematous from the first postoperative day,” Busin said.
The study
DMEK has a higher rate of failure than DSAEK, mainly because it is technically more challenging with a steeper learning curve, “possibly accentuated by lack of access to training,” Busin and co-authors said in the published paper.
“Surgeons who are unsure tend to manipulate the graft a lot and in some cases even implant it upside down. The rate of success and failure of DMEK is definitely more surgeon-dependent as compared with DSAEK,” Busin said.
In his hospital, 254 DMEK surgeries were performed over the study period, of which six failed; none had been performed by the most experienced surgeons. When accounting for regional referrals, there were 21 eyes with failed DMEK that underwent secondary UT-DSAEK.
A standardized UT-DSAEK technique was performed in all eyes. The donor graft was prepared using a microkeratome, aiming for a central thickness of 100 µm. The DMEK graft was removed, and the UT-DSAEK graft was inserted through a 3.2-mm clear corneal incision using the pull-through technique with the Busin mini-glide. All operations were without complication.
“We had excellent results,” Busin said. “At 1 year after UT-DSAEK, all corneas were perfectly clear, and the graft was barely visible at the slit lamp. When excluding four eyes with limited vision due to comorbidities, including AMD, retinal detachment and advanced glaucoma, all patients achieved vision between 20/25 and 20/20.”
In the literature
Other studies have measured the success of DMEK and DSEK/DSAEK after primary DMEK graft failure. Price and colleagues reported excellent results with DMEK as a secondary procedure, with 43% of the eyes achieving 20/20 vision, similar to their results with primary DMEK. However, re-bubbling was required once in 13% of the eyes and twice in 2%. Baydoun and colleagues reported a complication rate as high as 76.5% with repeat DMEK, including repeat failure and a re-bubbling rate of 6%. On the other hand, studies on Descemet’s stripping endothelial keratoplasty (Dapena and colleagues) or DSAEK (Arnalich-Montiel and colleagues) as a secondary procedure often reported suboptimal outcomes, which can be explained by the use of the manual technique in one case and by the use of thick DSAEK grafts in the other. Dickman and colleagues demonstrated in a study that graft thickness is inversely correlated with speed of visual recovery and visual outcomes.
“We have observed over years of experience that ultra-thin grafts, also as a primary procedure, have excellent visual outcomes, often comparable with those of DMEK,” Busin said.
Pros and cons
Whether to choose DMEK or UT-DSAEK as a primary procedure is ultimately the choice of individual patients, once they have been informed about the pros and cons of both options.
“I talk to them about the two options, telling them that the rate of complications is lower with DSAEK, around 1% as compared with 10% with DMEK. This also translates into a lower rate of re-intervention. On the other hand, I also say that visual recovery is faster with DMEK. Visual outcomes in the long term are more or less comparable if UT-DSAEK is performed, but if they want an immediate result, DMEK is better. I also explain that DMEK has a lower rate of immunologic rejection. At about 5 years, the risk is about 1% to 2% as compared with 6% of UT-DSAEK,” Busin said.
As a secondary procedure after DMEK failure, he has seen most patients choose UT-DSAEK.
“After a failed initial operation, they prefer to play safe and are quite prepared to wait longer for recovery whilst reducing the risk of being re-operated on for a third time,” he said.
The contrary also occurs in some cases. If patients are not satisfied with DSAEK results, they may want to have DMEK.
“Definitely, when patients have had immunologic graft rejection following PKP or DSAEK, we always perform DMEK to lower the risk of a second rejection. We know that the risk of rejection increases with every subsequent transplantation, and we hope to contain this escalation by performing DMEK,” Busin said.
Ultimately, both techniques are excellent, have advantages and disadvantages, and should be used wisely, according to the specific situation. Good corneal surgeons should be able to master both, he said. – by Michela Cimberle
- References:
- Arnalich-Montiel F, et al. Graefes Arch Clin Exp Ophthalmol. 2013;doi:10.1007/s00417-013-2460-y.
- Baydoun L, et al. Ophthalmology. 2015;doi:10.1016/j.ophtha.2014.07.024.
- Dapena I, et al. Br J Ophthalmol. 2010;doi:10.1136/bjo.2009.160945.
- Graffi S, et al. Br J Ophthalmol. 2018;doi:10.1136/bjophthalmol-2017-311834.
- Price MO, et al. Ophthalmology. 2015;doi:10.1016/j.ophtha.2015.04.037.
- For more information:
- Massimo Busin, MD, can be reached at Ospedale Villa Igea, Viale Antonio Gramsci, 42, 47122 Forlì (FC), Italy; email: mbusin@yahoo.com.
Disclosure: Busin reports no relevant financial disclosures.