Preserflo Microshunt And Intraocular Hypotension Impact Of Mitomycin C Concentration On Intraoperative And Short-Term Safety.

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 intraoperative and short-term safety and complication rates with the PreserFlo Microshunt in dependency of the concentration of mitomycin C (MMC) and with special consideration of intraocular hypotension.

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 (IOP) and the intra- and early postoperative surgical complications.

0.02% MMC: Mean IOP at baseline was 27.8±8.7 mmHg. One week after MIGS, 4 of the 132 eyes (3%) were hypotonic (IOP<6 mmHg), at 1 month, 2 eyes were still hypotonic, and at 6 months, no eye was hypotonic. All these hypotonic eyes had choroidal detachment. Overall, choroidal detachment was noted in 6% of eyes, choroidal swelling in 2%, and hyphema in 7%.
0.04% MMC: Mean IOP at baseline was 24.9±8.3 mmHg. One week after surgery, 14 of observed 341 eyes (4.1%) were hypotonic, at 1 month, 7 of 338 eyes were still hypotonic, and at 6 months, no eye was hypotonic. No choroidal detachment was determined in any of the hypotonic eyes. Choroidal detachment was noted only in 1% of eyes, choroidal swelling in 13%, and hyphema in 13%.

Regardless of the MMC concentration used, the PreserFlo MicroShunt provides a significantly effective safety profile. Only 4% of eyes were found to have a clinical hypotonic IOP of less than 6 mmHg after surgery. With the higher MMC concentration of 0.04%, more intraoperative and short-term complications occurred overall. Only 63% of these eyes had no abnormalities. However, most were classified as mild. In contrast, 83% of eyes treated intraoperatively with 0.02% MMC had no complications, but the observed cases were more severe.