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QUESTION

SHOULD I SEND A PATIENT WITH A LARGE CHRONIC MACULAR HOLE TO A RETINA DOCTOR? DO THEY EVEN OPERATE ON THOSE?

Avni P. Finn, MD, MBA
Tamer H. Mahmoud, MD, PhD

Yes, we do! Macular hole repair is a very successful surgery and most full-thickness macular holes close with conventional surgery involving vitrectomy, internal limiting membrane (ILM) peeling, and the use of gas tamponade. Nevertheless, about 10% of macular holes fail to close with this technique.¹

Large macular holes are defined by the International Vitreomacular Traction Study group as those that are more than 400 μm in diameter. Chronic holes are those present for longer than 6 months based on history. Large chronic macular holes present a surgical challenge for the vitreoretinal surgeon, but one that may be tackled with various newer surgical techniques. While some of these will close with the conventional technique, others do not and may have higher rates of recurrence, such as those macular holes associated with high myopia, retinal detachment, trauma, and juxtafoveal telangiectasia. A combination of different techniques have been employed to improve closure rates in these difficult macular holes, including scleral shortening techniques, macular buckles, inverted or free ILM flaps, autologous lens capsular flaps, autologous retinal transplant, and the use of adjuvant blood components.

Scleral Shortening Techniques

Highly myopic patients with full-thickness macular holes present a unique challenge. They often have thin, brittle ILM that is difficult to peel. The retina in these patients is stretched thin, with schisis or foveal detachment accompanying the hole. In highly myopic eyes, scleral shortening techniques have been used to decrease the degree of curvature of the eye and reduce the posterior staphyloma, thereby decreasing tractional forces on the retina and providing less surface area for the retina to cover along the posterior pole to allow holes to close. This technique was initially described using scleral resection but has since evolved to scleral imbrication whereby mattress sutures are placed in the temporal equatorial sclera, which imbricate the temporal sclera as they are tightened.2 While this process shortens the axial length and decreases the staphyloma, it is likely that vitrectomy and ILM peeling are the more crucial steps in closing the macular hole.

Scleral buckling for myopic macular holes is an old technique that has gained some renewed interest with newer buckling devices that may be safer and easier to use in pathologic myopes with macular hole, posterior staphyloma, and retinal detachment. In this technique, a specialized rubber radial element with a terminal plate designed to infold the macula is placed to decrease the stretching effect of the posterior staphyloma.³ Vitrectomy and ILM peeling are usually performed concurrently with the macular buckle. Effective and safe placement of the macular buckle remains a concern with this technique. Additionally, given postoperative complications, including subretinal and choroidal hemorrhage, erosion, diplopia, and focal retinal pigment epithelium atrophy, we favor the use of other techniques described.

Autologous Internal Limiting Membrane Flap

The initial report of the inverted ILM flap technique for a large macular hole was performed by peeling the ILM around the macular hole and leaving the central part of the ILM in place and inverting this to cover the macular hole.⁴ Various modifications have since been made to this technique, including peeling the ILM on only the temporal side of the fovea and covering the macular hole with a temporal ILM flap. Other groups have described peeling a free flap the same size as the macular hole and placing this inside the macular hole. As the ILM flap can be very flimsy and difficult to maneuver, injecting viscoelastic over the flap to secure it in place or adjusting the flap under perfluorocarbon may be useful adjuncts to this technique. In our experience, ILM flaps are most successfully used in patients with myopic macular holes.

The ILM flap acts as a scaffold for Müller cell and tissue proliferation. An inverted ILM flap is thought to induce glial cell proliferation. These proliferating glial cells then provide an environment suitable for photoreceptors to migrate to the fovea, explaining the improvement in vision. On optical coherence tomography, anatomic improvements are seen in the foveal contour, and there is some restoration of the ellipsoid zone and external limiting membrane.

Lens Capsule Flap

The lens capsule has recently been described as an alternative tissue scaffold. An anterior capsular flap can be harvested after the anterior capsulotomy in phakic patients or a posterior capsular flap can be harvested in a pseudophakic patient. The anterior capsule is thicker and more rigid than the flimsy posterior capsule, making it easier to maneuver into the macular hole and less likely to scroll in the hole. These flaps cannot be used when there is limited capsular material to harvest, such as in pseudophakic eyes with a prior posterior capsulotomy.⁵ The transparency of the tissue makes it difficult to see and manipulate during this procedure unless it is stained with a vital dye. Additionally, there is an increased risk of failure when posterior capsule is used for flap tissue, likely due to its tendency to curl rather than remain flat and fill the hole.

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