Outcomes of Primary Trabeculectomy versus Combined Phacoemulsification-Trabeculectomy Using Automated Electronic Health Record Data Extraction

Abstract

Purpose: Cataract is a known effect of trabeculectomy (TE), but some surgeons are hesitant to perform combined phacoemulsification-TE (PTE) due to a risk of increased TE failure. Herein, we compare intraocular pressure (IOP) lowering between trabeculectomy (TE) and phacoemulsification-TE (PTE) and investigate factors that impact patient outcomes.

Methods: We performed a retrospective study of adults undergoing primary TE or PTE at our institution from 2010 to 2017. We used Kaplan-Meier survival analysis to investigate time to TE failure, and Cox proportional hazards modeling to investigate predictors of TE failure, defined as undergoing a second glaucoma surgery or using more IOP-lowering medications than pre-operatively.

Results: 318 surgeries (218 TE; 100 PTE) from 268 patients were included. Median follow-up time was 753 days. Mean baseline IOP was 21.1 mmHg. There were no significant differences in IOP between TE and PTE groups beyond postoperative year 1, with 28.9-46.5% of TE and 35.5-44.4% of PTE groups achieving IOP ≤10. Final IOP was similar in both groups (p = 0.22): 12.41 (SD 4.18) mmHg in the TE group and 14.05 (SD 5.45) in the PTE group. 84 (26.4%) surgeries met failure criteria. After adjusting for surgery type, sex, age, race, surgeon, and glaucoma diagnosis there were no significant differences in TE failure.

Conclusion: This study suggests there is no significant difference in the risk of TE failure in patients receiving TE versus those receiving PTE.

Keywords: Glaucoma, cataract, trabeculectomy, phaco-trabeculectomy, combined surgery, intraocular pressure.

Figure 1:

Violin plot demonstrating the distribution of intraocular pressures in the operative eyes at pre-operative baseline and all post-operative visits following trabeculectomy or phaco-trabeculectomy. POD = post-operative day, POM = post-operative month, POY = post-operative year.

Figure 2:

Bar chart demonstrating the mean number of intraocular pressure-lowering medications used in the operative eye at pre-operative baseline and all post-operative visits following trabeculectomy or phaco-trabeculectomy. Whiskers indicate the standard error. POD = post-operative day, POM = post-operative month, POY = post-operative year.

Figure 3:

Kaplan-Meier curves for composite outcome of receiving a greater number of glaucoma medications compared to pre-operative baseline or undergoing a second laser or surgical glaucoma procedure. Log-Rank test to compare eyes that underwent primary trabeculectomy (Trab) compared to those that underwent combined phacoemulsification and trabeculectomy (Phaco-Trab) did not show a significant difference in the chance of survival (p = 0.17).