Gas superior to air tamponade in lower quadrant vitrectomy

By Sarah Guy, medwireNews Reporter

Gas and air are suitable tamponading agents for use during vitrectomy for rhegmatogenous retinal detachment (RRD), however air tamponade should only be used in cases that are restricted to the superior quadrants, study findings show.

In RRD cases involving the lower quadrants, gas is superior to air, report the study researchers in the British Journal of Ophthalmology.

"Endotamponade is commonly used at the conclusion of vitrectomy for RRD, for macular holes, and for other indications of vitrectomy when existing or iatrogenic retinal breaks are detected intraoperatively," explain Stevie Tan and colleagues from the University of Amsterdam in the Netherlands.

"It serves as a temporary barrier to prevent fluid in the vitreous cavity from entering retinal breaks during the formation of a retinal adhesion," they add.

The team assessed the results of air tamponade versus gas (sulfur hexafluoride [SF₆]) tamponade during vitrectomy in 524 eyes of 523 patients with RRD treated between June 2006 and June 2010. All patients were followed up for a mean period of 3 months.

Tan and co-investigators report a shift toward the use of SF₆ as a gas tamponading agent since it has a shorter shelf life, at 2.5 days, than the other common gas agent used - octafluoropropane - at 5.0 days.

In all, 158 RRD cases were treated with air tamponade, and 366 were treated with SF₆ gas. Virectomy led to attached retinas in 85.1% of cases, and eyes treated with air tamponade had an 81.0% success rate, while those treated with gas had an 86.9% success rate. The only significant difference between patients in the two treatment groups was that those treated with air tamponade had significantly more macular-on detachments, more phakic eyes, and less involvement of the inferior retinal quadrants, note the researchers.

Indeed, this latter factor appeared to be a confounder; while tamponade type did not initially reach significance as a factor for treatment success in analysis, after accounting for involvement of inferior quadrants (among other potential confounders), air versus gas as the type of tamponade was associated with a 1.97 odds ratio for success.

Furthermore, a subanalysis of the effect of tamponade type showed that the success of vitrectomy in this patient population was significantly better in patients with involvement of inferior quadrants treated with gas tamponade compared with air, at 84.7% versus 69.6%, remark Tan et al.

"The present findings suggest that air should only be considered as a tamponading agent in vitrectomy for RRD if none of the inferior retinal quadrants are involved," they suggest, concluding that "further prospective study is needed to confirm these findings, and to address effects on functional outcome."

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