Preserflo Microshunt – Intraoperative Application Of 0.02% And 0.04% Mitomycin C: A Comparison Of Clinical Outcomes And Complications With A Follow-Up Of Up To 2.5 Years After Surgery.

Over the past decade, a number of minimally invasive glaucoma surgeries (MIGS) have been developed for patients with open-angle glaucoma. The PreserFlo Microshunt (Santen) is a glaucoma implant for subconjunctival drainage via external access. The shunt is made of styrene-isobutylene-styrene, which was originally developed for vascular surgery.
Here we present our latest results on the efficacy of intraocular pressure (IOP) reduction, safety and complication rates, and postoperative management with the PreserFlo Microshunt as a function of the concentration of the intraoperative antifibrotic agent mitomycin C (MMC).

All patients were treated and observed by two surgeons at Breyer Kaymak Klabe Augenchirurgie Düsseldorf, Germany.

The PreserFlo Microshunt was implanted in 132 eyes (100 patients) and in 382 eyes (270 patients), respectively. During surgery, MMC-soaked sponges with MMC concentrations of 0.02% and 0.04% were applied under the sub-Tenon layer for 2 minutes. We monitored the intraocular pressure, the number of postoperative medication as well as visual acuity, visual field defects and endothelial cell loss. Regular monitoring of the filter zone by swept-source-OCT was additionally performed if necessary..

The mean age of the analyzed patient groups was 68±12 (0.02% MMC) and 69±12 (0.04% MMC) years. 73% and 70% had no prior surgical glaucoma treatment, 44% and 50% were pseudophakic, respectively. Mean IOP decreased from 27.8±8.7 mmHg to 13.7±3.8 mmHg and 16.8±4.7 mmHg after 1.5 and 2.5 years (0.02% MMC) and from 24.9±8.3 mmHg to 12.5±2.7 mmHg and 12.6±2.5 mmHg (0.04% MMC), respectively. The decrease of number of medications was 2.3±1.3 and 1.6±1.4 (0.02% MMC) and 2.5±0.8 and 2.5±0.8 (0.04% MMC) 1.5 and 2.5 years after surgery.
In glaucoma patients treated with 0.02% MMC and 0.04% MMC, needling was 43% (57 of 132 eyes) and 19% (74 of 308 eyes observed), respectively, and the revision rate was 24% and 6%.

Regardless of the MMC concentration used, the PreserFlo MicroShunt provides a significantly effective reduction in intraocular pressure for up to two and a half years after surgery, while reducing the use of IOP-lowering medications.
In contrast, there is a clear dependence of the needling and revision rates on the MMC concentration used. Thus, these complication rates are 2.3 and 4 times higher, respectively, when using the lower MMC dose of 0.02% than when using 0.04% MMC.