Postoperative posture

The latest Amsterdam Retina Debate, presented online by EURETINA 2020 Virtual, was a vitreoretinal battle on the topic of postoperative care after retinal detachment surgery. The question was: do we know how to correctly posture these patients in order to prevent retinal displacement and macular folds?

The debate, hosted by Sarit LesnikOberstein MD, Amsterdam, The Netherlands, was an entirely British affair between David Yorston MD, Glasgow, Scotland, and Rumana Hussain MD, Liverpool, England. Pre-debate polling indicated that 72% of the online audience members were convinced that we already know how to posture correctly, while 28% had their doubts. Dr Yorston might have had a difficult time defending that initial advantage.

Dr Yorston began with a defence of the utility of posturing. As one of the authors of the PostRD trial, he might be considered an expert on the topic. The PostRD trial was a randomised controlled trial that compared the effect of face-down positioning versus support-the-break positioning on retinal displacement and distortion after macula-involving retinal detachment (RD) repair in 239 patients.

“Our study shows that face-down positioning is associated with a reduction in the rate and amplitude of postoperative retinal displacement after macula-involving RD repair and a reduction in binocular diplopia,” he said.

No association was found with visual acuity or postoperative distortion. However, the study “was not powered to show changes in function, only in anatomical changes”, he added.

“In practice, I posture everyone facedown for four hours,” he added. “What’s more important than the length of time for posturing is the immediacy of the posturing, because there’s always some residual subretinal fluid, regardless of the surgical technique.”

Dr Hussain made a strong case for the argument that we really don’t know how best to posture our retinal detachment patients in the immediate postoperative period.

“Why do we posture our patients immediately postoperatively?” asked Dr Hussain. “The only reason is the prevention of macular folds, which occurs because there’s some residual subretinal fluid with redundant pliable retina, which gets trapped during fluid-air exchange and pinches the posterior pole.”

When macular folds occur, it’s “a bit of a disaster”, she continued, but the incidence is difficult to ascertain. Based on a review of the literature, Dr Hussain concluded that it is an uncommon complication.

A Japanese paper suggests that it is more common in outpatients than inpatients.

“This was due to the reduced posturing compliance of face-down posturing in outpatients. However, the problem with all of these papers is that they talk about the posturing but do not mention whether there was residual subretinal fluid, whether heavy liquids were used during surgery or whether posterior or anterior retinotomies were used for drainage of subretinal fluid. So, we don’t really know the rate of folds, especially after different procedures, like scleral buckling or vitrectomy,” she observed.

What complicates matters is the presence of subclinical retinal displacement, as visualised on postoperative autofluorescence imaging, and the recent study suggesting that up to 88% of macula-off retinal detachment patients experience symptomatic metamorphopsia, so this may be a bigger issue than we previously realised.

“So, how do prevent this from happening?” she asked. “Well, these shifts and folds result from residual subretinal fluid, with a big gas bubble splinting the redundant retina at the posterior pole.”

The question remains: “Who do we posture? All retinal detachment patients? Only those with visible residual subretinal fluid? Only patients with bullous retinal detachments? Or maybe only those with macula-off or fovealsplitting detachments? And then there are the questions of how to posture: face-down, supine, temporal down or steam roller, not to mention the serious question of compliance.”

“The PostRD Trial, as my opponent

Rumana Hussain MD

mentioned, showed a significant difference in the retinal displacement measured; however, subjective results were approximately the same between groups,” she pointed out. So, what’s the point? “Maybe we shouldn’t be treating scans and images and autofluorescence, but rather patients’ symptoms and satisfaction.”

So, what are Dr Hussain’s suggestions to prevent this disastrous complication?

“If you want to prevent retinal folds, intraoperative prevention is what makes the difference. This includes stringent drainage of all the subretinal fluid. Do we know how to posture our retinal detachment patients? The answer is no!”

In the end, both debaters could agree on two important features of postoperative posturing. First: rapid posturing in the immediate postoperative period. Second: limitation of movement in the hours thereafter, so that the posture that is assumed remains stable for about four hours.

Dr Yorston joked that the number one threat to postoperative posturing is the friendly nurse who comes to offer the patient a nice cup of tea an hour after surgery, thus interrupting the posturing.

Dr Hussain, however, had the last laugh, as the post-debate poll showed that nearly about 50% of online viewers polled remained convinced that the issue of postoperative posturing could be laid to rest.