Rebubbling Does Not Worsen Outcomes After Descemet Membrane Endothelial Keratoplasty

By Will Boggs MD

September 08, 2020

NEW YORK (Reuters Health) - Rebubbling to address graft detachment does not worsen outcomes after Descemet membrane endothelial keratoplasty (DMEK), according to a retrospective study.

DMEK, a minimally invasive partial corneal transplant, involves the use of bubbling, the introduction of air or sulfur hexafluoride (SF6) gas into the anterior chamber to ensure approximation of the donor graft to the recipient cornea. Rebubbling is used when graft detachments occur.

Dr. Sebastian Siebelmann of the University of Cologne, in Germany, and colleagues evaluated the influence of rebubbling on postoperative outcomes after DMEK and the need for rebubbling on the contralateral eye in their study of 499 eyes (430 patients, 624 rebubbling procedures).

Most eyes (79.8%) received one rebubbling, 16.6% received two rebubblings, 2.6% received three rebubblings and 1% received four or five rebubblings after the same DMEK surgery.

The overall rebubbling rate was significantly higher in the fellow eye of patients who subsequently received DMEK on that eye (58.8%), when compared with the overall rebubbling rate (32.3%).

Air was used for anterior-chamber tapenade in 83.6% of rebubbling procedures, and SF6 gas was used in the remaining cases.

The overall best spectacle-corrected visual acuity (BSCVA) as logarithm of the minimum angle of resolution after 12 months of all rebubbled patients was 0.13 (approximate Snellen equivalent, 20/28), the researchers report in the British Journal of Ophthalmology.

At 12 months, the overall number of rebubblings had no influence on BSCVA, mean central corneal thickness (CCT), mean endothelial cell density (ECD), or endothelial cell loss.

Similarly, there was no difference in the postoperative outcomes if patients were rebubbled within the first seven, 14, or 21 days after DMEK.

Dr. Silke Oellerich of the Netherlands Institute for Innovative Ocular Surgery, in Rotterdam, who earlier reported similar visual outcomes among DMEK patients who did and did not undergo rebubbling, said, "We found it striking that multiple rebubblings do not seem to affect postoperative ECD. In our experience, eyes that were rebubbled showed higher endothelial cell loss. If no significant endothelial cell damage is induced by the act of rebubbling, then it could be that any observed higher cell loss is a reflection of either an initial large drop from extensive graft manipulation, or a faster rate of cell attrition in 'predisposed' eyes with more complex pathologies or eyes that received grafts of 'lower potential.'"

"Even so, we still tend to conservatively perform a rebubbling in cases of graft detachment where we suspect mechanical graft displacement as the cause and try to avoid or delay rebubbling where we suspect delayed endothelial function, as these tend to spontaneously attach," she told Reuters Health by email.

"The authors also found that patients that required a rebubbling in their first DMEK eye seemed to be at higher risk for a graft detachment in their second DMEK eye," Dr. Oellerich said. "This should prompt good preoperative counseling about the probability of a graft detachment in the second eye and good preoperative surgical planning to ensure good graft attachment (e.g., minimal graft manipulation with no-touch technique, sufficient eye pressurization at end of surgery) and avoid another rebubbling."

Dr. Siebelmann did not respond to a request for comments.

SOURCE: British Journal of Ophthalmology, online August 17, 2020.