One-Year Comparison of Efficacy and Safety of PreserFlo MicroShunt with Mitomycin C Applied by Sub-Tenon Injection Versus Sponge

Abstract

Introduction: This study was performed to compare the efficacy and safety of PreserFlo MicroShunt (PMS) implantation with mitomycin C (MMC) applied by sub-tenon injection versus conventional application by MMC-soaked sponges.

Methods: This retrospective, 1-year cohort study included 100 eyes of 100 patients with glaucoma who underwent PMS implantation with MMC (0.4 mg/ml) delivered either by sub-tenon injection (50 eyes) or via soaked sponges (50 eyes). The primary outcome measure at 1 year was intraocular pressure (IOP) reduction, with complete success defined as an IOP reduction of ≥ 20% and achieving a target IOP of ≤ 21 or 18 mmHg without the use of medication. Secondary outcomes, including corneal endothelial cell density (CECD) loss, the number of medications, and complications, were assessed and compared between the groups.

Results: Sustained reductions in mean IOP were observed in both groups over the 1-year follow-up, with no significant differences between the groups. The complete success rate, with a target IOP of ≤ 21 mmHg after 1 year, was 19.3% in the sponge group and 26.4% in the injection group. The qualified success rate was 59.0% and 87.4% in the sponge and injection groups, respectively. A longer survival rate was observed in the injection group than in the sponge group when IOP was below 21 mmHg. The mean CECD significantly decreased (P < 0.01) from baseline to each postoperative follow-up time point in both groups. At 1 year postoperatively, the percentage of total CECD loss was 8.1% in the sponge group and 8.0% in the injection group. However, no significant differences in mean CECD values, the number of medications, or adverse events were found between the groups.

Conclusions: PMS implantation with sub-tenon injection of MMC was comparable in terms of efficacy and safety to traditional MMC delivery via soaked sponges. However, the injection group demonstrated a significantly higher success rate than the sponge group.

Keywords: Corneal endothelial cells; Glaucoma; Glaucoma surgery; Intraocular pressure; MIBS.

Fig. 1

Flow chart of the selection process of the study participants in the retrospective cohort study. MMC mitomycin C

Fig. 2

Graph showing intraocular pressure (IOP) at baseline and during follow-up. Data are expressed as mean values with standard deviation. ***P < 0.001 for baseline versus 12-month comparison within the groups of patients who underwent PreserFlo MicroShunt implantation with different mitomycin C (MMC) delivery methods (sponge vs. sub-tenon injection), based on the paired Wilcoxon signed-rank test

Fig. 3

Scatter plot of postoperative intraocular pressure (IOP) values compared with preoperative IOP at the 1-year follow-up. Dots are color-coded according to subgroups. The solid diagonal line represents matching baseline IOP and IOP at the 1-year follow-up. The dashed diagonal line represents a 20% reduction in mean IOP. The dashed horizontal lines indicate postoperative IOP thresholds of 18 and 21 mmHg

Fig. 4

Kaplan–Meier plots comparing the success rates of the two subgroups of patients who underwent PreserFlo MicroShunt implantation with different mitomycin C (MMC) delivery methods (sponge vs. sub-tenon injection). A Complete success, defined as IOP ≤ 21 mmHg, ≥ 20% IOP reduction, and no medication allowed. B Qualified success, defined as IOP ≤ 21 mmHg, ≥ 20% IOP reduction, and medication allowed. C Complete success with IOP ≤ 18 mmHg, ≥ 20% IOP reduction, and no medication allowed. D Qualified success with IOP ≤ 18 mmHg, ≥ 20% IOP reduction, and medication allowed. The dashed lines represent the 95% confidence interval curves. P values was calculated by log-rank test

Fig. 5

Time course of postoperative corneal endothelial cell density (CECD) over 1 year of follow-up. Data are expressed as mean values with standard deviation. ***P < 0.001

Fig. 6

Graphical representation of the relationship between corneal endothelial cell density (CECD) loss and tube–endothelium (TE) distance in patients who underwent PreserFlo MicroShunt implantation with different mitomycin C (MMC) delivery methods: A sponge soaked with MMC and B sub-tenon injection of MMC. A Spearman correlation test was used for the correlation analysis

Fig. 7

Postoperative change in the number of antiglaucoma medications over 1 year compared with preoperative values. Data are expressed as mean values with standard deviation. ***P < 0.001