XEN® implantation: an effective strategy to stop glaucoma progression despite prior minimally invasive glaucoma surgery

Abstract

Purpose: The aim of this study was to evaluate whether XEN® implantation is a reasonable and safe method to lower the intraocular pressure (IOP) and amount of medication for adult primary open-angle glaucoma (POAG) over a 3-year period. The influence of the type of anesthesia, previous glaucoma surgery, and postoperative interventions on the outcome were examined.

Methods: In this retrospective study, 96 eyes were included. XEN® implantation was performed as sole procedure under general (n = 86) or local anesthesia (n = 10). IOP and number of glaucoma medication were assessed preoperatively: day 1, week 6, month 3, 6, 12, 24, and 36. Further outcome parameters were Kaplan-Meier success rates, secondary intervention, and complication rates.

Results: IOP decreased from 20.7 ± 5.1 to 12.8 ± 2.5 mmHg at the 36-month follow-up (p < 0.001) and glaucoma therapy was reduced from 3.3 ± 0.8 to 1.2 ± 1.6 (36 months, p < 0.001). Transient postoperative hypotony was documented in 26 eyes (27.1%). General anesthesia resulted in a significant improvement of the survival rate compared to local anesthesia (77% vs. 50%, p = 0.044). Prior iStent inject®, Trabectome®, or SLT laser had no significant impact, such as filter bleb revision. The number of postoperative needlings had a significantly negative influence (p = 0.012).

Conclusion: XEN® implantation effectively and significantly lowers the IOP and number of glaucoma therapy in POAG in the 36-month follow-up with a favorable profile of side effects and few complications. In case of IOP, general anesthesia has a significant positive influence on the survival rate, whereas prior SLT or MIGS does not have significant impact.

Keywords: Glaucoma; MIGS; POAG; XEN® gel implant.

Fig. 1

Change in intraocular pressure (IOP) as a timeline graph after XEN® gel implantation, *p < 0.001

Fig. 2

Scatterplot: each point represents one eye showing the preoperative IOP value on the abscissa, and the postoperative IOP values on the ordinate, respectively. The oblique line indicates no change, weather the diagonal lines illustrate the percentage reductions (20%, 30%, and 50%). Different IOP targets (21, 18, and 16 mmHg) are represented by the horizontal lines

Fig. 3

Kaplan–Meier graph for the probability of qualified success. a All cases in total. b intubation anesthesia: solid, black line; local anesthesia: dotted, black line. The endpoints were defined according to the following success criteria: IOP ≤ 18 mmHg and ≥ 20% reduction in IOP compared with baseline values. Failure was assumed if the target criteria were not reached on 2 consecutive visits. General anesthesia has a significant effect on the qualified success (p = 0.044, Breslow (generalized Wilcoxon))

Fig. 4

Kaplan–Meier graph for probability of qualified success. a All cases in total 12 months following surgery. b All cases with complete follow-up until 36 months postoperatively. The endpoints were defined according to the following success criteria: IOP ≤ 18 mmHg and ≥ 20% reduction in IOP compared with baseline values. Failure was assumed if the target criteria were not reached on 2 consecutive visits

Fig. 5

Change in glaucoma medication as a time line graph after XEN® gel implantation, *p < 0.001