While the surgical strategy for the repair of idiopathic and traumatic macular holes is generally similar — vitrectomy and posterior vitreous removal, internal limiting membrane (ILM) peeling/removal, gas bubble, and postoperative face-down positioning — surgeons must take a few differences into account. First, the likelihood of successful surgical hole closure with a good visual acuity outcome is high for idiopathic macular hole, making the decision to proceed with the procedure relatively straightforward. In comparison, as reported in the literature, the success rate of surgery for traumatic macular hole is lower, but the likelihood of spontaneous closure is higher. These factors make the decision to proceed with surgery somewhat more complicated. The surgeon and patient must weigh waiting for potential spontaneous closure, perhaps 2 to 3 months, against waiting too long after the trauma, which could have a negative impact on outcomes.

The most significant difference between surgery for idiopathic and traumatic holes is that traumatic macular hole patients tend to be younger and have an intact posterior hyaloid. Therefore, it’s critically important that during the procedure, the surgeon separate and elevate the vitreous from its normal configuration at the retinal face so the edges of the macular hole can be attached to one another. Typically, the process is initiated with a micro-vitrectomy instrument, and triamcinolone is often used to improve visualization of the vitreous. In cases where the separation proves more difficult than usual, a soft-tipped instrument may be used to aspirate tissue at the optic nerve head and along its sides. If separation still isn’t achieved, use of indocyanine green (ICG) dye, which in a small number of cases may react with the vitreous to partially stain it, may facilitate vitreous elevation.

New Technique Gains in Popularity

The poorer surgical closure rate of traumatic macular hole as compared with idiopathic macular hole may be due in part to vitreous movement where the impact occurred that leaves an area of missing or devoid tissue. In an effort to address this, a new technique, the inverted ILM flap technique, has been developed and shown to be successful, albeit in case series so far.^1-3 In this technique, rather than completely removing the ILM, the surgeon leaves remnants of the membrane attached to the margins of the macular hole and inverts them into the hole prior to fluid/air exchange. The rationale is that the Müller cell fragments contained in the ILM pieces left attached may induce gliosis inside the retina as well as on the ILM surface, leading to closure of the hole. In addition, it’s believed that the remaining ILM may serve as scaffolding to enable photoreceptors to re-assume their correct position near the fovea.

My colleagues and I have employed the inverted ILM flap technique many times. We recently used it to close a macular hole in a 22-year-old male patient who was referred to us after a deployed vehicle airbag caused blunt trauma to his left eye. At presentation, visual acuity OS was hand motion (Figure 1). We performed pars plana vitrectomy and ILM peeling utilizing ICG, leaving a flap of ILM intact. We inverted the flap over the center of the whole, in effect plugging the hole with the tissue. We used intraoperative OCT to verify that the flap was in proper position. Postoperatively, macular edema resolved and visual acuity improved to 20/400 (Figure 2). The scotoma that had been present decreased in size. We didn’t expect visual acuity to improve further, given the duration of the condition in this case. Visual acuity following surgical repair of traumatic macular hole varies based on the presence or absence of concomitant conditions and the amount of trauma an eye suffers. Many of our patients who experienced minor trauma have done quite well.

Variations of the inverted ILM flap technique have also been used. In one variation, a partial flap is rotated over the hole. In another variation, a flap is created from another area of the ILM and placed over the retina.

Surgical Platform Advances and OCT Help to Improve Macular Hole Repair

Recent advances in vitreoretinal surgery systems have improved the surgeon’s ability to separate and treat the posterior hyaloid, the most crucial step in the repair of traumatic macular hole. The replacement of peristaltic pump systems with Venturi pump systems has enabled more efficient vitreous removal. System fluidics have improved via the abilities to use high cut and aspiration/vacuum rates and to vary duty cycle.

OCT is now the established mainstay, along with clinical exam, for macular hole diagnosis and management. Preoperatively it enables the surgeon to assess the configuration of the hole, including size, which is a major prognostic factor. For larger-diameter macular holes, the anatomical closure rate decreases dramatically. OCT can also show whether the hyaloid or vitreous is elevated or separated in some areas, guiding the surgeon toward the most opportune location to use a cutter or pick to facilitate complete separation. Postoperatively, OCT is the best way to determine whether closure of the hole has been accomplished. When a hole remains open, most surgeons have a low threshold for repeating surgery unless the configuration of the hole is such that it would likely never close. For example, one of the most significant prognostic indicators a surgeon may see is atrophy accompanied by a lack of cystic edema at the edges of the hole. In that scenario, another surgery would not be performed.

At our institution, we’ve been increasing our use of intraoperative OCT as part of several types of vitreoretinal surgeries, including macular hole repair procedures. Intraoperative OCT allows us to monitor vitreous dynamics in the OR, including localizing the flap when we’re performing an inverted ILM flap procedure to ensure it’s on the area of interest. According to the results of our PIONEER study,⁴ intraoperative OCT informs surgeon decision-making by providing immediate feedback regarding the completion of surgical objectives.

In addition to the usefulness of intraoperative OCT, we’ve also learned that, contrary to a previously widely held belief, it is indeed possible to obtain useful OCT images through gas tamponade following macular hole repair. It’s definitely possible to perform OCT through gas and localize the vitreous and the macular hole to see whether it has closed or not. This information helps us to determine whether the surgery has been a success, without having to wait 6 or as many as 12 weeks for the gas to resolve. We typically capture OCT images 3 to 4 days after surgery.

Evaluation of the Technique is Ongoing

As more surgeons investigate and gain experience with the inverted ILM flap technique for traumatic macular hole repair, it will be interesting to see to what extent it may be able to improve our overall successful closure rate. ■

References

1. Michalewska Z, Michalewski J, Adelman RA, Nawrocki J. Inverted internal limiting membrane flap technique for large macular holes. Ophthalmology. 2010;117(10):2018-2025.
2. Abou Shousha MA. Inverted internal limiting membrane flap for large traumatic macular holes. Medicine (Baltimore). 2016;95(3):e2523.
3. Mahalingam P, Sambhav K. Surgical outcomes of inverted internal limiting membrane flap technique for large macular hole. Indian J Ophthalmol. 2013;61(10):601-603.
4. Ehlers JP, Dupps WJ, Kaiser PK, et al. The prospective intraoperative and perioperative ophthalmic imaging with optical coherence tomography (PIONEER) study: 2-year results. Am J Ophthalmol. 2014;158(5):999-1007.

Dr. Singh is a staff physician at Cleveland Clinic Cole Eye Institute, associate professor of ophthalmology at Cleveland Clinic Lerner College of Medicine, and medical director of informatics at the Cleveland Clinic in Cleveland, Ohio.