New Macular Hole Technique: ILM Repositioning

The Surgical Technique section is one of the highlights of RETINA. New and innovative techniques are introduced in this section with accompanying surgical videos. It’s certainly a section that I look forward to every issue. We plan to periodically feature content from Surgical Techniques for RETINA Roundup, and we hope that you will find the posts stimulating.

In a recent paper published online ahead of print, Peiquan Zhao’s team from Shanghai reported a new technique for macular hole surgery (link to paper here: Tian et al, RETINA 2017 [Epub ahead of print]). There have been many iterations of ILM flap techniques and “stuffing” complex macular holes with various materials. However, Dr. Zhao’s technique takes quite a unique approach, where ILM is peeled, but repositioned back into place.

The authors call the technique “Peeled internal limiting membrane reposition.” In a nutshell, the ILM is peeled as one large sheet over the macular hole, but it remains hinged on one end, and the sheet is repositioned back into place with PFO, and fluid-gas exchange is performed. Therefore ILM is peeled and released from the retinal surface, but it is draped back onto the retina, where it was previously.

So why should anyone do this? Does this work?

ILM Repositioning

ILM peeling has increased our single-surgery macular hole closure rate, but there are theoretical concerns about microscotomas and other unknown effects of peeling the Muller cell footplates. One microstructural effect is inner retinal dimpling (also known as dissociated nerve fiber layer), which is commonly seen on OCT after ILM peeling surgeries.

By re-draping the ILM back into place, the investigators show that the inner retinal microanatomy retains its smooth surface, and in this series, all holes closed. It’s unknown if this translates into better functional outcomes, but it’s definitely an intriguing concept that makes us think more about the properties of the ILM.

While this is a small study of just 10 patients, we look forward to further larger studies to show its efficacy and whether the improved microanatomy translates into superior visual and functional outcomes.

Addendum 9/1/2017:

I reached out to Dr. Zhao (PZ) to ask him a few questions via email, and he graciously replied with nice pearls:

YY: How did you come up with this technique?

PZ: I think preserving the integrity of inner retina while relieving the tractional force around the macular hole simultaneously is the advantage of this novel technique. Although traditional ILM peeling has improved the singe-surgical MH closure rate, it has unknown effects on retinal morphology and function. This is the reason why we came up with this idea. Regarding the morphology of the patients in our series, all patients achieved MH closure and no inner retinal dimplings were observed on en-face scanning. This result was extremely encouraging.

YY: Do you think the repositioning technique will result in better macular function?

PZ: Will the preserved ILM work, and how? Will the Muller cells rebuild effective connections with the preserved ILM? We think the novel technique preserves the integrity of the inner retina and may contribute to the recovery of macular function. To confirm this, we are implementing a randomized controlled trial to study the morphologic and functional changes after ILM repositioning, including MH closure rate, visual acuity changes, central retinal thickness, inner retinal dimpling rate, M chart score (metamorphopsia), mf-ERG, and microperimetry.
However, this new technique is not applicable in MH cases with obvious epiretinal membranes. Because during the epiretinal membrane peeling procedure, it may tear the ILM off partially, which makes the reposition of the fixed ILM flap impossible. This new technique is also challenging and the learning curve can be steep.

YY: Thank you very much for your insights!

Yoshihiro Yonekawa, M.D.

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