Factors influencing the effectiveness of trabeculectomy: following materials of the City Multidisciplinary Hospital No. 2

BACKGROUND: Despite the ever-expanding arsenal of IOP-lowering surgeries, trabeculectomy remains the most common procedure amongst them. Therefore, the identification of factors reducing its effectiveness and potentially being able to change the surgical treatment plan is of particular importance. AIM: To identify factors reducing trabeculectomy effectiveness. MATERIALS AND METHODS: The study group consisted of 443 consecutively enrolled patients who were operated in 20162020 in Saint Petersburg City Multidisciplinary Hospital No. 2 for primary open-angle decompensated glaucoma and then observed for 6 to 24 months. Using statistical research methods, factors that significantly affected the impact of the procedure were identified. RESULTS: The main predictors of trabeculectomy failure following the order of decreasing importance of established relations (p) were: loss of effectiveness of the preceding IOP-lowering procedure (р = 0.0001), dry eye syndrome (р = 0.013), number of drop instillations per day (р = 0.041), and excessive preservative load due to unnecessarily aggressive topical glaucoma treatment (р = 0.039). An obvious demonstration of excessive therapy is a simultaneous administration of four IOP-lowering medications. It also causes scarring of the procedure area, especially in patients previously operated for glaucoma. Null preservative load and prostaglandin monotherapy are associated with guaranteed complete success of trabeculectomy. Unlike the intensity of medical glaucoma treatment, its duration does not have such a significant impact on trabeculectomy outcomes (р = 0.270). Close to a significant one is the relationship between poor surgical outcomes and advanced stages of the disease (р = 0.052). CONCLUSIONS: The main factors affecting the effectiveness of trabeculectomy were failure of the previous IOP-lowering surgeries; concomitant dry eye syndrome, arising or being aggravated by unduly intense and prolonged pharmacological effects on the eye surface; as well as delayed appliance for surgical IOP normalization at advanced disease stages.