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Surgeons successfully adopt no touch DMEK technique
Challenges included deciding whether to outsource graft preparation, limiting the number of graft detachments and obtaining organ-cultured donor tissue.
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A standardized no-touch Descemet’s membrane endothelial keratoplasty technique was successful but somewhat challenging in the hands of surgeons newly trained in the procedure, according to a study.
OSN Europe Edition Board Member Gerrit R.J. Melles, MD, PhD, and colleagues published the study in JAMA Ophthalmology.
“The most significant finding of the study was that the standardized no-touch DMEK technique and the manual techniques for DMEK donor tissue preparation were feasible in the hands of at least 18 different surgeons in 11 different countries,” Melles told Ocular Surgery News. “Furthermore, this study confirmed that no-touch DMEK is a well-established procedure with optimal clinical outcomes and a low complication rate which can be performed by almost every corneal surgeon with proper training in many different clinical settings.”
Gerrit R.J. Melles
The standardized no-touch DMEK technique is relatively safe, easy to learn and reproducible, Melles said.
“Furthermore, the no-touch technique allows the surgery without direct manipulation of the tissue, which in theory diminishes intraoperative endothelial cell loss,” Melles said. “The learning curve, as in any new procedure, included a process of understanding the behavior of the tissue and development of maneuvers, actions and materials that should be or should not be performed and/or used.”
Patients and methods
The retrospective study included 431 eyes of 401 patients who underwent DMEK. Indications for DMEK were Fuchs’ endothelial dystrophy (68.2%) and bullous keratopathy (31.8%).
Surgeons successfully performed DMEK graft preparation in 92.9% of cases; seven of the 18 surgeons had backup corneas available in case preparation of the initial graft failed.
All surgeons used the standardized no-touch DMEK technique with modifications.
DMEK was performed concurrently with phacoemulsification in 38 eyes (8.8%). For eyes that underwent second DMEK procedures, only the primary procedure was analyzed.
The main outcome measures were best corrected visual acuity, endothelial cell density, and intraoperative and postoperative complications.
BCVA data were available for 275 eyes. Endothelial cell density measurements were available for 133 eyes.
Outcomes and observations
BCVA improved by two or more lines in 258 eyes (93.8%), was unchanged in 12 eyes (4.4%) and decreased in five eyes (1.8%).
Among eyes followed for 1 month to 6 months, BCVA was 20/40 or better in 217 eyes (78.9%), 20/25 or better in 117 eyes (42.5%) and 20/20 or better in 61 eyes (22.2%).
Mean donor endothelial cell density decreased by 47%, from 2,625 cells/mm2 preoperatively to 1,399 cells/mm2 at 6 months postoperatively; the decrease was statistically significant (P = .02).
Intraoperative complications included difficulty with graft insertion and unfolding and/or positioning the graft in five eyes (1.2%). Small intraoperative hemorrhages occurred in two cases (0.5%).
Partial graft detachment was the most common postoperative complication, occurring in 124 eyes (28.8%); 43 (34.7%) of those grafts required a second transplant.
Complete graft detachment occurred in 18 eyes (4.2%); grafts were positioned upside-down in seven cases (1.6%).
Partial graft detachment was no more than one-third of the graft surface area in 80 eyes (18.6%) and more than one-third of the surface area in 31 eyes (7.2%). Size of the detachment was not specified in 13 cases (3%).
“[The main challenges faced by surgeons] new to DMEK were to decide whether graft preparation should be outsourced or performed during surgery, to limit the number of graft detachments and secondary procedures, and to obtain organ-cultured donor corneal tissue,” Melles said.
Seventeen of the 18 participating surgeons chose to continue performing DMEK; one chose to perform Descemet’s stripping automated endothelial keratoplasty instead of DMEK.
A follow-up study coordinated by Perry Binder, MD, is currently ongoing to continue monitoring the introduction of DMEK as a routine technique for corneal endothelial disorders, Melles said. – by Matt Hasson
Reference:
Monnereau C, et al. JAMA Ophthalmol. 2014;doi:10.1001/jamaophthalmol.2014.1710.For more information:
Gerrit R.J. Melles, MD, PhD, can be reached at Netherlands Institute for Innovative Ocular Surgery, Laan Op Zuid 88, 3071 AA Rotterdam, Netherlands; email: melles@niios.com.Disclosure: Melles is a consultant for DORC International/Dutch Ophthalmic USA.
Perspective
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Marianne O. Price, PhD
This study provides valuable insights into the DMEK learning curves of multiple surgeons. It confirms that the key challenges are graft attachment, tissue preparation and assessment of the graft orientation within the eye. Graft attachment rates were higher with use of donor tissue stored in organ culture solution, glass injectors and a complete air fill for at least 1 hour. Most of the surgeons prepared the tissue themselves. Eye bank pre-dissected tissue alleviates tissue preparation concerns for the surgeon and is becoming more widely available. Two techniques were used to evaluate graft orientation within the recipient eye: the Moutsouris sign and asymmetrical marks on the graft edges. Other helpful techniques not utilized in this study include use of an intraoperative slit beam or an S-mark on the donor tissue. Overall, the learning curve was such that 17 of the 18 participating surgeons have continued with DMEK, while one felt more comfortable returning to DSAEK. The authors are to be congratulated on this excellent study; it can be very difficult to collect this type of data.
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