Minimally Invasive Subretinal Perfluorocarbon Liquid (PFCL) Removal

Perfluorocarbon liquid (PFCL) is widely used in retinal surgery; however, it can be complicated by subretinal retention that can affect/threaten fovea. A number of different approaches have been explored to remove retained PFCL. Here, we investigate the use of microneedles with internal diameters as small as 49 G.

An in vitro model was used to examine the rate of aspiration of a fixed volume of 250 µL PFCL, whereby 30, 41, 43, and 49 gauge needles were examined. An ex vivo porcine model was then used to confirm whether subretinal PFCL could be consistently aspirated without blockage. Finally, this technique was used during pars plana vitrectomy (PPV) in 10 patients presenting with subfoveal or parafoveal retained PFCL.

Mean aspiration of 250 µL PFCL required 0.22, 0.33, and 0.78 minutes for the 30, 41, and 43 gauge needles at 200 mm Hg extraction pressure. Microneedle aspiration of 250 µL required maximal vacuum settings of 650 mm Hg to obtain a measurable average time to aspiration of 3.34 minutes. Ex vivo aspiration of subretinal PFCL required 400-650 mm Hg vacuum, where this was repeatable without any needle blockage. In 10 patients treated with PPV and microneedle subretinal PFCL aspiration, all cases were successful. Mean visual acuity change was of LogMAR -0.08 (±0.12).

We recommend the clinical use of microneedles as a minimally invasive surgical option when considering direct retained PFCL removal.

We confirmed the flow properties of microneedles for PFCL aspiration in vitro and ex vivo before successfully applying this to treat retained PFCL in patients.