The inverted internal limiting membrane (ILM) flap technique is not only a safe and effective procedure for treating macular holes, but compared with conventional ILM peeling, it is significantly more effective for achieving macular hole closure in certain situations, said Stanislao Rizzo, MD, at Retina Subspecialty Day 2016.
Chicago-The inverted internal limiting membrane (ILM) flap technique is not only a safe and effective procedure for treating macular holes, but compared with conventional ILM peeling, it is significantly more effective for achieving macular hole closure in certain situations, said Stanislao Rizzo, MD, at Retina Subspecialty Day 2016.
“In our experience, the inverted ILM flap technique is more effective than conventional ILM peeling for treating large macular holes measuring >400 microns, myopic macular holes, macular holes with chorioretinal atrophy, and myopic macular holes with retinal detachment,” said Dr. Rizzo, chairman, Department of Ophthalmology, Careggi University Hospital, Florence Italy.
The inverted ILM flap technique was first reported in the literature in 2010 in a paper by Michalewska et al. that presented the results of a randomized clinical trial [Ophthalmology. 2010;117:2018-2025]. The surgery begins with core vitrectomy and dye staining.
However, instead of the ILM being completely removed, a remnant is left attached to the edges of the macular hole. The remnant is then inverted upside-down and used to cover the macular hole.
Dr. Rizzo noted that since that original publication, two other variants of this innovative macular hole surgery technique have been described in the peer reviewed literature. One is a perfluoro-n-octane-assisted single-layered technique reported by Shin et al. [Retina. 2014;34:1905-1910].
And most recently, a paper by Andrew et al. described autotransplantation of the ILM [Retina. 2016;36:834-837.]. In the latter approach, a piece of the ILM is taken out of the macula and inserted into the bottom of the macular hole.
Tissue repair mechanism
Dr. Rizzo said that all three techniques are considered to work via the same mechanism.
“The inverted flap ILM contains Müller cell fragments and may induce glial cell proliferation that results in filling of the defect," he said. "In addition, the ILM may serve as a scaffold for tissue proliferation, providing an environment for the photoreceptors to assume correct positioning in proximity to the fovea, improving postoperative vision.”
Future studies taking advantage of new retinal imaging techniques and functional tests may enable better delineation of the anatomic and functional changes associated with the inverted flap technique and of the underlying mechanisms of the postoperative improvement of the retinal architecture.
In order to investigate whether there are any prognostic variables predicting differences in anatomic outcomes between the inverted ILM flap technique and conventional ILM removal, Dr. Rizzo undertook an analysis of a single-surgeon series of 620 eyes with a full-thickness macular hole (FTMH) operated on between 2011 and 2014. There were 300 cases that underwent the inverted ILM flap technique and 320 treated with ILM peeling. All eyes had follow-up to 12 months after surgery, and the overall closure rate in the series was about 85%.
With eyes stratified into two groups by macular hole size, his analyses found no statistically significant difference in the macular hole closure rate between the inverted flap technique and ILM peeling for holes measuring <400 microns (97% versus 96%; p = 0.54). For larger holes, however, the closure rate was significantly higher using the inverted flap technique compared with ILM peeling (96% versus 79%; p < 0.001).
There was also no significant difference in the anatomic success rate comparing the inverted flap technique and ILM peeling among eyes with axial length <26 mm-the macular hole closure rate in both groups was 94% (p = 0.82).
In longer eyes
In longer eyes, however, the inverted flap technique was again significantly superior to ILM peeling for achieving macular hole closure (88% versus 39%; p < 0.001).
In addition, the macular hole closure rate was more than two-fold higher after surgery using the inverted flap technique than after ILM peeling in eyes with myopic macular holes with chorioretinal atrophy (78% versus 32%; p = 0.007), noted Dr. Rizzo.
“The presence of atrophy means more challenging surgery,” he noted.
Dr. Rizzo also reported on a small series of 24 eyes with myopic FTMH and retinal detachment operated on using either the original inverted flap technique or with ILM transplantation. After follow-up to 12 months, the overall macular hole closure rate in this group was 92%.
He highlighted the efficacy of the technique by presenting images from three eyes that showed complete disappearance of the macular hole and the retinal detachment.