MACULAR HOLE SURGERY

Face down positioning provides no benefit following macular hole surgery, the latest findings from an Australian multicentre prospective study suggest.

Alex Hunyor MD, a principal investigator of the Australian Macular Hole Study, discussed the latest results of the ongoing study during a session of the American Society of Retina Specialists in San Diego, California.

“The main aim of the study was to have a useful audit tool for surgeons, where we could have a large dataset for benchmarking of results of macular hole surgery, and assess the factors affecting hole closure and visual results,” said Dr Hunyor, Vitreoretinal Surgeon at Sydney Eye Hospital.

The Australian Macular Hole Prospective Survey is a national audit of macular hole surgical outcomes that began recruitment in November 2008. The study tracks all macular hole cases performed by participating surgeons. Initially this was done with a paper entry form system, but the system now involves online data entry.

“This has made it lot faster and more simple. The aim is to have it quick and unambiguous, in order to get good quality data. Respondents enter baseline information including hole stage and size, vitreous attachment and surgical information. They then follow up later with hole closure data, visual results, lens status and any complications. This can mostly be done by staff. I tested it myself recently and it takes less than five minutes. It is a real credit to my colleague Dr Rohan Essex, who devised the system and pioneered the study.”

The utility of prone positioning of patients after macular hole surgery still stirs heated debate. Earlier studies of this question had shortcomings in design and produced ambiguous results. A small number of studies showed some apparent benefit of face down positioning in some patients, but other research casts doubts on this approach, he noted.

While the initial rate of prone positioning reported in 2008 was 90 per cent, this has declined steadily, and in 2014 is at 60 per cent. Surgeons report ordering anywhere from 0-15 days of postoperative prone positioning. During that same period ILM (internal limiting membrane) peeling has become a standard part of the surgical procedure.

“ILM peeling is now pretty universal. It is worth noting that we have not used ICG dye in Australia for 10 years. Rather we are using various blue dyes. ILM peeling has significantly improved success rates with no apparent downside,” he said.

There was no difference in success between the shorter acting SF6 gas and the longer acting C3F8 gas. Those using the longer acting gas may have chosen it based on the idea that those cases were less likely to succeed, Dr Hunyor noted.

With 90 per cent follow-up of more than 2,000 cases, primary hole closure was achieved in 95 per cent of cases. Larger holes of longer duration were less likely to be successfully treated. Patients starting with better baseline vision had a lower chance of improving by three lines. Older age was associated with less improvement. Patients who had undergone combined phacovitrectomy were perhaps not surprisingly more likely to have good early visual outcomes. Overall complication rates were low, with very few cases of retinal detachment (1.5 per cent) and no cases of endophthalmitis.

As far as the big question was concerned, “the study suggests that face down positioning confers no benefit. In the land down under, there is much less face down under. We would like to see a randomised controlled clinical trial to evaluate this further. I do think there may be a small role for prone positioning in patients who are slightly underfilled with gas on the first postoperative day,” said Dr Hunyor.

“We have not used face down positioning since 1995,” noted Paul Tornambe MD, director of the San Diego Retina Research Foundation and past president of the American Society of Retina Specialists, who published the first paper on no face down positioning in 1997.

“It requires a leap of faith for most retinal surgeons to believe that face down positioning is not necessary. If you advocate face down positioning you believe that the buoyancy of the bubble has some positive effect that helps hole closure. I can’t agree with that.”

Alex P Hunyor:
aphunyor@gmail.com

Paul Tornambe: TornambePE@aol.com