This article is more than 5 years old. Information may no longer be current.
Sulfur hexafluoride tamponade reduces detachment rate in DMEK
Longer-lasting SF6 tamponade performed well compared with air tamponade.
Click Here to Manage Email Alerts
Tamponade with 20% sulfur hexafluoride was associated with a markedly lower rate of graft detachment than 100% air tamponade in Descemet’s membrane endothelial keratoplasty, a study found.
Because most graft detachments occur in the early postoperative period after DMEK, there is a need for a longer-lasting tamponade agent to decrease the need for air reinjections. The use of 20% sulfur hexafluoride (SF6) has previously shown a low reinjection rate of 6.6%, but concerns exist about toxicity to the corneal endothelium.
A retrospective study, published in Ophthalmology, compared the clinical outcomes and endothelial cell survival rate using 20% SF6 or 100% air to tamponade the donor graft.
“The use of this relatively long-standing tamponade allows us to significantly diminish the rate of re-bubblings needed after some cases of DMEK,” lead investigator Jose L. Güell, MD, PhD, told Ocular Surgery News.
Tamponade with SF6, air
The case series consisted of 81 pseudophakic patients with Fuchs’ endothelial dystrophy or pseudophakic bullous keratopathy who underwent DMEK. Tamponade was performed with 20% SF6 in 42 eyes with a mean follow-up of 3.2 years and with 100% air in 39 eyes with a mean follow-up of 3.9 years.
Three years after surgery, mean logMAR corrected distance visual acuity significantly improved from 0.48 to 0.04 in the SF6 group and from 0.67 to 0.09 in the 100% air group (P < .001).Corrected distance visual acuity of 20/25 or better was achieved in 36 eyes (85.71%) in the SF6 group and 32 eyes (82.05%) in the 100% air group, with no significant difference between the groups.
No significant changes in spherical equivalent refraction, cylinder and refractive astigmatism were noted throughout the follow-up period in both groups.
Three years after surgery, mean endothelial cell density decreased by 30% and 32% in the 20% SF6 group and the 100% air group, respectively. Central corneal thickness was also significantly reduced after 3 years compared with preoperative measurements in both groups.
The graft re-bubbling rate was significantly lower at 2.38% in the 20% SF6 group vs. 12.8% in the 100% air group.
The authors noted that 20% SF6 persists in the anterior chamber for 2.8 days and 100% air lasts for 1.6 days.
Postoperative management
Because both approaches have the same standard learning curve, Güell said there is no difference in using 20% SF6 except for the postoperative management.
“Instead of having an air bubble of about one-third or one-fifth of what you got the day before, you still have about two-thirds there, or plenty of gas, because the main reason we use SF6 is because it remains longer than air,” he said.
An additional benefit of using SF6 is the ease of patient compliance during postoperative management.
“Because you want to use this leftover air in the anterior chamber and need to teach patients to have a particular position throughout the day in order to use this air to push the membrane, it can obtain, psychologically, a much better compliance from the patient for the first few days, which I think that also is positive for this extremely low rate or almost no cases of re-bubbling,” Güell said.
Many DMEK surgeons currently use this approach in Europe, and Güell thinks the use of 20% SF6 tamponade will continue to grow around the world.
“I think that it’s something that is being taken into account by most DMEK surgeons,” he said. “Some of those who have more or higher rate of re-bubblings, I think they might consider it more seriously.”
Güell and colleagues plan to continue long-term follow-up of all patients who have had tamponade performed with 20% SF6 after DMEK, while also further studying the procedure as a whole.
“We need to fully investigate the way to better improve long-term endothelial cell loss after DMEK, not only with studies such as the one we just performed, but also protecting the graft and so on,” he said. – by Kristie L. Kahl and Matt Hasson
- Reference:
- Güell JL, et al. Ophthalmology. 2015;doi:10.1016/j.ophtha.2015.05.013.
- For more information:
- Jose L. Güell, MD, PhD, can be reached the Instituto de Microcirugia Ocular, c/Josep Maria Llado 3, 08035 Barcelona, Spain; email: guell@imo.es.
Disclosure: Güell reports no relevant financial disclosures.