Article

Autologous Retinal Patch Graft for Refractory Large Macular Holes

Incorporating a new technique into your practice.

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The conventional repair of full-thickness macular holes (FTMHs) involves pars plana vitrectomy (PPV), with internal limiting membrane (ILM) peeling under visualization using stains such as indocyanine green dye or brilliant blue, which has been used extensively in Europe and was recently approved by the FDA for use in the United States. Gas tamponade with postoperative positioning may be used based on lens status and surgeon preference. Idiopathic macular hole closure rates typically exceed 90%.1 Chances of anatomic success following standard surgery are lower in chronic, large (>400 microns), myopic, and traumatic holes, as well as in recurrent or refractory cases.1 Hole closure rates in these scenarios range from 50% to 92%.1 The closure rate of FTMH that are larger than 500 microns is approximately 50% with conventional repair.1

For patients who failed vitrectomy with ILM peeling and tamponade, an option of an autologous neurosensory retinal free graft was published by Grewal and Mahmoud in 2016.2,3 Human amniotic membrane transplantation into subretinal space under the edges of recurrent macular holes and retinal breaks was described by Rizzo et al in 2019.4

Noy Ashkenazy, MD, is a vitreoretinal fellow at the Bascom Palmer Eye Institute in Miami, Florida. Ryan Zukerman, BS, is a third-year medical student at the University of Miami, Miller School of Medicine, applying for ophthalmology residency. Ninel Z. Gregori, MD, is professor of clinical ophthalmology at the Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, and the chief of ophthalmology at the Miami Veterans Affairs Hospital in Miami, Florida. The authors report no relevant financial disclosures. Acknowledgment: Dr. Gregori would like to thank Steve Charles, MD and Tamer Mahmoud, MD, PhD, for teaching the retinal patch graft technique and reviewing the manuscript. Reach Dr. Gregori at ngregori@med.miami.edu.

AUTOLOGOUS FULL-THICKNESS RETINAL GRAFT FOR RECALCITRANT MACULAR HOLES

In the initial report by Grewal and Mahmoud, the 2-disc diameter full-thickness graft was harvested above the superotemporal arcade, moved over the inner retina, covering the hole completely, and held down by perfluoro-n-octane heavy liquid (PFO), which was then directly exchanged to silicone oil tamponade.2 The visual acuity improved from 20/200 to 20/80 at 3 months, and distortion and scotoma markedly improved. In a recent multicenter international study, Grewal et al reported results of 41 eyes with refractory FTMH that failed conventional repair with ILM peeling and largest basal diameter of 621 microns to 2600 microns.3 All eyes underwent PPV, autologous neurosensory retinal transplant with gas, silicone oil tamponade, or short-term PFO tamponade. Closure was achieved in 87.8% overall, and in 89.3% of highly myopic eyes. Among eyes with anatomic closure, 33.3% had stable vision, 52.3% improved at least 3 lines, and 13.8% worsened.

Autologous retinal graft procedures are being slowly adopted for failed or very large FTMHs. Techniques vary among surgeons in terms of graft harvest location, graft size, and type of tamponade used (silicone oil, gas, or short-term PFO). Recently, we performed several of these cases using the technique popularized by Steve Charles, MD, of Charles Retina Institute, which involves the use of short-term PFO tamponade. Here we discuss the surgical steps and share our recommendations for successful incorporation of this graft technique into one’s surgical practice.

SELECTING HARVEST LOCATION

While various locations may be used for harvesting a free graft, taking a graft just inferior to the inferotemporal arcade has several advantages. Proximity to the arcade will assure that the graft will need to be moved only a short distance to the hole, and the scotoma resulting from the harvest site will be located superiorly in the visual field, hidden by the patient’s lid. None of our patients so far endorsed a scotoma with this harvest location.

SELECTING THE SIZE OF THE RETINAL GRAFT

The graft size should be larger than the diameter of the hole and should overlap the hole edges 360 degrees. It has been suggested that the diameter of the retinal flap should be approximately 0.5 disc diameter larger than the size of the macular hole (MH) to cover the hole completely and to allow for some decentration postoperatively. In our experience, the graft tends to shrink over time, and the double retinal layer seen over the MH edges, due to overlap of the graft and the host retina, lessens or disappears with time as the graft integrates into its space.

PREPARING THE HARVEST LOCATION

The planned area of the graft should be demarcated by a row of laser, leaving unlasered central area the size required to cover the hole, as described above. The next step is to elevate the neurosensory retina to be harvested by injecting balanced salt solution (BSS) loaded into a 10-mL syringe and capped with a subretinal injection cannula such as the extendible 23 gauge/41 gauge subretinal DORC needle (1270.ext) or 23-25 gauge/38 gauge PolyTip cannula (reference number 3219) from MedOne Surgical, Inc. The syringe is connected to the vitrectomy viscous fluid control port using the tubing in the oil pack. The infusion pressure is set to 10-18 mmHg, typically at 12-14 mmHg. The cannula tip can be trimmed at 45 degrees with scissors to ease penetration of the retina. The cannula is inserted just outside of the laser line. After some of the graft is elevated with BSS, mild endodiathermy is applied to all the blood vessels seen near the laser line in preparation for cutting the graft.

CUTTING THE GRAFT

Vertical or curved scissors may be used to cut the graft. We prefer vertical scissors because they have a nonsharp inferior edge and a guillotine superior blade. The vertical scissor can be inserted into a retinal opening typically visible inside one of the endodiathermy touch sites. The graft is then cut just inside the endolaser markings, leaving a small hinge to keep the graft in place.

STABILIZING AND MOVING THE GRAFT

To stabilize the graft, PFO is injected to cover the macula and the harvest site. Next, ILM forceps with wide platforms are used to grasp an edge of the graft. If needed, the second hand can be used to assist in breaking the graft hinge using either a scissor or a second ILM forceps. Once the graft if free, it is dragged alone the retinal surface and positioned over the hole. It is important not to elevate the graft off the retinal surface to prevent rolling of the edges. The graft should be centered over the hole and the edges should be gently flattened against the retina.

CHOOSING A TAMPONADE AGENT

We prefer the technique of Steve Charles, MD, to completely fill the eye with PFO to the lens or IOL. To do so, additional PFO is injected with a dual-bore cannula, which comes in 23-, 25-, and 27-gauge sizes (DualBore Side Flo cannula; MedOne Surgical, Inc.). The cannula allows BSS to exit while PFO is being injected. The infusion is turned off at this step, and once PFO is seen to exit into the infusion cannula and no more BSS is seen to exit through the dual-bore cannula, the vitreous cavity is filled with PFO completely. Typically, 2 vials of PFO are required. While fluid–air–gas or direct PFC–silicone oil exchange have been done in these cases, the use of short-term PFO tamponade for 1 to 2 weeks prevents graft dislocation and may achieve better functional results.3 All sclerotomies are sutured to prevent PFO escape. With PFO in place, we prefer to keep the patient supine for 2 hours after the procedure for the graft to adhere, and then release home without any special positioning.

POSTOPERATIVE COURSE

The eye can be imaged with OCT and fundus photography the next day to ensure the graft is in place and the hole is no longer open. The patient is taken back to the OR to remove PFO a week later. Air–fluid exchange can be performed to ease the removal. PFO has been shown to be safe in the eye, without unusual inflammation, elevated intraocular pressure, or flap displacement after PFO removal.3

VISUAL OUTCOMES

Postoperative visual acuity improvement after traditional macular hole repair depends on various factors, including the size of the MH as well as the integrity of preoperative inner segment-outer segment junction/ellipsoid zone and external limiting membrane.5 Preoperative size of the FTMH plays a major role in the mean visual outcome. Holes less than 400 microns close to a mean vision of 20/50, while holes larger than 400 microns rarely exceed 20/150 following repair.6 Visual acuity outcomes in cases managed with observation alone have been shown to stabilize around 20/200 to 20/400.7

In the 41 cases reported, Grewal et al reported visual improvement of at least 3 lines in 52.3% among eyes with anatomic closure and vision worsening in 13.8%.3 Significant decrease in the size of ellipsoid zone and external limiting membrane defects were seen in some eyes. The graft contains photoreceptors, mostly rods and some cones, as well as potentially some retinal progenitor cells, which may explain the visual improvement seen in some eyes after this procedure. No cases of proliferative vitreoretinopathy, intraocular inflammation, suprachoroidal hemorrhage, or neovascularization were seen. Depending on the size and chronicity of the hole, improvements in vision cannot be guaranteed; however, significant improvement in central scotoma is almost always seen. Patients often describe the scotoma as a spiral leading to a central blind spot, which disappears postoperatively.

CASE REPORT

A 64-year-old male presented complaining of blurry vision in the left eye for 30 years, following left-sided head trauma (Figure 1). He was diagnosed with a very large macular hole and was told by multiple providers that there was nothing that could be done for his vision. He described a very bothersome “swirl” in his central vision and expressed an interest in doing anything possible in order to improve his symptoms. The smallest diameter of the hole was 1,160 microns and the largest diameter at the base of the hole was 1,786 microns. After a discussion of various surgical options and likely success rates, the patient decided to proceed with an autologous retinal patch graft surgery.

Figure 1. Fundus photo (A) and OCT (B) at preoperative visit of a 64-year-old male presenting with a large macular hole.

The patient was managed with a 23-gauge PPV, membrane peeling, autologous free retinal patch graft, endolaser, and perfluorocarbon injection, and then 1 week later, he underwent perfluorocarbon removal (Figure 2). Visual acuity improved from 20/200 at baseline to 20/150 at postoperative month 2 (Figure 3), and finally to 20/80 after cataract was removed 5 months later. OCTs continues to show that the macular hole has closed (Figures 4 and 5), with the most recent follow-up at 11 months after the surgery. OCT angiography shows no graft revascularization, which preserves the foveal avascular zone. The patient continues to enjoy disappearance of the swirl and dense blind spot in his vision, and reports improved binocular vision.

Figure 2. Fundus photo (A) and OCT (B) 1 day after retinal patch graft surgery in a 64-year-old male.

Figure 3. Fundus photo 2 months after retinal patch graft surgery in a 64-year-old male.

Figure 4. Optical coherence tomography 2 months after retinal patch graft surgery showing outer retinal structures.

Figure 5. Optical coherence tomography at 4 months after retinal patch graft surgery showing stable closed macular hole in a 64-year-old male.

CONCLUSION

Adoption of this newer retinal graft technique gives surgeons an alternative surgical approach in cases recalcitrant to conventional surgical techniques, and it provides surgeons an opportunity to continue learning and evolving their surgical skills. However, it is not recommended for eyes with extensive chorioretinal scarring, panretinal photocoagulation, neovascularization, or any other condition where a healthy graft cannot be obtained. RP

REFERENCES

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