The evidence remains unclear

Does positioning patients face down improve outcomes after surgery for large full-thickness macular holes?

Researchers examining this question in a clinical trial concluded the answer remains unclear after determining there is insufficient evidence showing that facedown positioning following surgery is more likely than face forward positioning to close large macular holes.

However, Saruban Pasu, MBBS, MD, National Institute of Health Research Biomedical Research Centre, London, England, and colleagues did find that positioning patients face down resulted in better visual acuity outcomes.

The results of their study were published in JAMA Ophthalmology.

Full-thickness macular defects most commonly affect older adults (55 and over). According to the American Society of Retina Specialists, several conditions increase the risk of the condition, including vitreal traction, whereby the vitreous gel, through normal aging, shrinks and pulls away from the retina, creating a macular hole in the process. These full-thickness macular holes can severely impact sight and have an incidence of 8 per 100,000 persons.

A vitrectomy is the most common surgical treatment for the condition and involves the surgical removal of the vitreous gel and the placement of a gas bubble in the eye to keep the edges of the macular hole closed until it heals. According to Pasu and colleagues, there is some evidence indicating that for holes of a certain size (at least 400 μm minimum linear diameter) facedown positioning after surgery improves the rate of hole closure. They suggested, however, the evidence is “insufficient to draw firm conclusions with which to guide practice.”

Therefore, the aim of this study was to determine whether positioning patients facedown postoperatively improves the outcomes for large (≥400 μm) full-thickness macular holes.

The authors conducted a randomized, parallel group superiority trial at 9 sites across the United Kingdom. It included 185 participants with an idiopathic full-thickness macular hole of at least 400 μm minimum linear diameter and a duration of fewer than 12 months. The participants were randomized 1:1 to either position facedown or face forward for 8 hours daily for five days after vitrectomy.

The primary outcome was closure of the macular hole at a follow-up of 3 months. Secondary outcomes included best-corrected visual acuity at 3 months, and participant-reported experience of positioning on a scale from 0 (very difficult) to 10 (very easy).

Pasu and colleagues observed macular hole closure in 85.6% of patients who were advised to position face forward and 95.5% who were advised to position facedown (adjusted odds ratio, 3.15; 95% CI, 0.87-11.41).

At the median macular hole size (488.5 μm), the odds ratio of 3.15 corresponded to an absolute risk difference of 4.1% (95% CI, −0.8%-9.1%), or a number needed to treat of 24. For all participants, the unadjusted odds ratio was 3.54 and the risk difference was 9.9%, for a number needed to treat of 11.

The mean (SD) improvement in best-corrected visual acuity at 3 months was 0.34 (0.69) logMAR in the face forward group and 0.57 (0.42) logMAR in the facedown group (adjusted mean difference, 0.22 (95% CI, 0.05-0.38).

Patients did find face forward positioning easier to perform. The median participant-reported ease-of-positioning score (using a 10-point scale in which 0 was very difficult and 10 was very easy) was 9 in the face forward group and 6 in the face down group, while the proportion of participants reporting a score of 5 or more was 92.7% in the face forward group compared to just 56.1% in the face down group.

“The results do not prove that facedown positioning following surgery is more likely to close large macular holes compared with facing forward but do support the possibility that visual acuity outcomes may be superior,” concluded Pasu and his colleagues.

In a commentary accompanying the study, William E. Smiddy, MD, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, and colleagues, noted that the study found statistically significantly better mean visual acuity in the facedown positioning group and that these results “are paramount to the patient and should probably be considered the most important outcome metric.”

They also noted that the 3-month visual acuity table in the study by Pasu and colleagues indicated that at least 25% of the eyes in patients in the facedown positioning group had good visual acuity whereas at least 25% of the eyes of patients in the face forward group had a visual acuity worse than legally blind. That, combined with needed to treat results of either 11 or 24, provides “compelling evidence” that positioning patients facedown leads to clinically significant macular hole surgery results.

The study “does not truly establish that there is no clear evidence regarding the need for face down positioning,” observed Smiddy and colleagues. “Rather, the clinically significant differences that collectively favor face down position are compelling. Yet, while these results do not encourage the wholesale desertion of face down positioning, they at least are sufficient to encourage the patient and surgeon to attempt surgery in such a patient who, for whatever reason, will not be able to maintain a face down position stringently.”

  1. The evidence is still unclear whether facedown position of patients following surgery for large full-thickness macular holes is superior to face forward positioning in successfully closing macular holes.

  2. However, facedown positioning does result in improved visual acuity.

Michael Bassett, Contributing Writer, BreakingMED™

None of those quoted in this article had any disclosures.

Cat ID: 240

Topic ID: 92,240,730,192,240,460,160