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OCT-based positioning regimen for macular hole surgery varies with risk factors
Patients with two or three risk factors may benefit from a full 7 days of prone positioning.
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A modified OCT-based positioning regimen based on risk factors may be used to obtain complete, persistent closure of macular holes or to determine the duration of postoperative positioning, according to a study.
If a patient has no high-risk factors for failure, defined as high myopia, chronic holes for more than 1 year or large holes greater than 400 µm, the surgeon may choose to stop positioning once the hole is confirmed on OCT imaging to be closed. In cases with one risk factor, the surgeon may want to consider extending the positioning for a few days after the hole is closed. In the presence of two or three risk factors, the study authors suggested a full 7 days of prone positioning even if the hole is closed on postoperative day 1.
“We believe that in the absence of risk factors [for failure], patients will greatly benefit from the reduced positioning requirements of an OCT-based regimen,” the authors said in the study published in Retina. “However, surgeons should also be aware that closure of macular holes on postoperative day 1 does not guarantee maintained hole closure for patients with risk factors.”
Recommended regimen
The chart review evaluated medical records of 35 eyes of 33 patients who underwent macular hole repair after an OCT-based positioning regimen was instituted.
All surgeries were performed through a 23-gauge pars plana vitrectomy, and patients were advised to maintain prone positioning until the hole was confirmed to be closed based on daily OCT images.
At baseline, mean visual acuity was 20/220 with a mean hole size of 465 µm, and no holes had an element of vitreomacular traction.
Six patients had high myopia, 13 patients had chronic holes, and 19 patients had large holes.
After a mean follow-up of 7.7 months, final mean visual acuity was 20/135.
Adequate OCT images were obtained in 31 gas-filled eyes on postoperative day 1, 34 on postoperative day 2 and 35 on postoperative day 3. In order to obtain adequate images, the study authors recommended that the focus on the OCT machine should be set between –10 D and –20 D.
“OCT images can be obtained through a gas bubble reliably after adjusting the focus on your OCT machine with the appropriate myopic shift,” study investigator David R. Chow, MD, FRCSC, told Ocular Surgery News.
Risk factors
In total, 28 eyes had persistent closure of macular holes with the OCT-based positioning regimen.
Twenty-seven holes were confirmed closed on postoperative day 1; 32 were confirmed closed on postoperative day 2 and 3; and 33 were confirmed closed on postoperative day 5. However, closed holes began reopening after week 1 postoperatively with 31 holes confirmed closed on postoperative day 7; 29 were confirmed closed on postoperative day 8 through 14; and 28 holes were confirmed closed 1 month postoperatively.
“One of the strongest learning points to ascertain from this series is that late reopening of an apparently closed macular hole on early postoperative OCT is a real possibility,” the study authors said. “Surgeons should be aware which patients are at risk for this occurrence and alter their positioning regimens appropriately.”
In the absence of high-risk factors, the closure rate was 92%. The presence of two or three of the high-risk factors demonstrated an 85% and 74% closure rate, respectively.
“OCT-based positioning can be used to determine if the hole is closed to determine the duration of positioning necessary,” Chow said. “Macular holes that appear closed on OCT early on postoperatively may reopen, particularly in traditional high-risk patients, such as high myopia, chronic holes or large holes, if prone positioning is stopped. As a result, prolonged positioning regimens of at least 3 days are recommended for this group of patients.”
Necessity of prone positioning
Patients who undergo macular hole surgery largely complain about postoperative positioning due to physical, mental and medical difficulties. Therefore, the concept of shorter positioning in combination with tamponades had been previously recommended.
“There is a growing belief in some of the retina community that prone positioning is not necessary at all or only for 1 night in macular hole surgery,” Chow said.
Chow and colleagues, however, recommended a longer duration of prone positioning based on the number of risk factors associated with the patient.
“This study identifies that some high-risk patients can appear initially closed postoperatively but will reopen if prone positioning is stopped,” he said. “As a result, we strongly believe that high-risk patients should get at least 3 days of prone positioning irrespective if their hole appears closed on day 1 postoperatively. For patients without high-risk features, though, if the hole is closed on day 1 postoperatively, prone positioning can be confidently stopped.” – by Kristie L. Kahl
- Reference:
- Chow DR, et al. Retina. 2015;doi:10.1097/IAE.0000000000000410.
- For more information:
- David R. Chow, MD, FRCSC, can be reached at Toronto Retina Institute, 208-6 Maginn Mews, North York, ON, Canada M3C 0G9; email: davidrchow@me.com.
Disclosure: Chow reports no relevant financial disclosures.
Perspective
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Nikolas London, MD
It is nice to see a continuing movement to minimize face-down positioning for our macular hole patients. Chow and Chaudhary present the initial and persistent closure rates for a series of 35 eyes with macular holes, of which nearly two-thirds were larger than 400 µm, present for a year or longer, and/or associated with myopic degeneration. A regimen of truncated face-down positioning was employed, with discontinuation once the hole appeared closed. They reported a less-than-ideal single operation persistent closure rate of 80%, with a startling 15% rate of apparent hole reopening, more commonly in eyes with one or more risk factors. The authors conclusion was that holes associated with these risk factors need longer face-down positioning despite appearing closed on OCT.
This is a fascinating report and it raises a few interesting points. Part of the move to minimize face-down positioning is based on the rationale that the role of the gas bubble is not to tamponade and actively push on the hole, but simply to isolate it from liquid vitreous until the hole is closed, maybe a few days longer for good measure. This healing process may take a few days for a small hole, but likely takes longer than a week for large holes, such as those in this study. Face-down positioning certainly isolates the hole, essentially as long as the bubble is present, but so does non-supine positioning. An SF6 bubble will cover the hole for nearly a week, and a C3F8 bubble will cover the hole for nearly a month. I am impressed that the authors here used SF6 in such relatively large holes, particularly in pseudophakes. In my experience, patients would greatly prefer a prolonged bubble in the eye, which is often simply annoying, as opposed to a taxing regimen of strict face-down positioning. None of my patients are asked to do face-down positioning, but rather to avoid lying on their backs.
I also wonder about the use of trans-gas OCT imaging. In my experience with this technology, it is challenging to obtain high-quality images with enough low axial resolution to convince me that I am seeing the fovea and that the hole is closed. If an open hole was assumed to be closed when it was not and prone positioning was abandoned, then the patient would likely then sleep on his back, impeding hole closure and possibly accounting for the low success rate and apparent hole reopening. Food for thought at least.
Lastly, I wonder about the cases treated with repeat surgery and whether any residual internal limiting membrane (ILM) was discovered. In my experience, this is a common finding in holes that reopen or do not close. A full ILM peel at least 1 disk diameter around the hole is critical to surgical success.
In the end, I like the authors description of risk factors for difficult-to-close macular holes and will likely use them in my practice. However, this will take the form of selecting a longer-acting tamponade for these patients rather than the authors conclusion of prolonging face-down positioning.
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