Objective: To analyze the efficacy and safety of minimally invasive vitrectomy (PPV) with or without intraoperative injection of dexamethasone intravitreal implant (DEX) for the treatment of Idiopathic Macular Epiretinal Membrane (IMEM), by comparing the relevant indicators.
Methods: A retrospective study design was used to collect 49 patients (49 eyes) who were diagnosed with IMEM (Gass2) and underwent surgical treatment(PPV+phaco+IOL implantation) at Huizhou Central People’s Hospital from January 2022 to June 2023. According to their treatment plan, they were divided into a non-combined injection DEX group (25 cases, 25 eyes) and a combined injection DEX group (24 cases,24 eyes). All patients underwent comprehensive optometry before and after surgery, and their best corrected visual acuity (BCVA) was recorded. Scan the central macular thickness (CMT) within 6x6mm of the macular area, while scanning the average ganglion cell layer (GCL) thickness. Record whether the elliptical zone (EZ) within 1x1mm of the macular area is complete and continuous. Use OCTA mode to scan the superficial capillary layer (SCP) of the retina within a range of 6x6mm, and record the measurements of vascular density (VDs) in the central area and the area of the foveal avascular zone (FAZ). Measure the patient's intraocular pressure using a non-contact tonometer. Follow up for 6 months and record the above indicators, with BCVA and CMT followed up for 1 year. Perform statistical analysis of data using SPSS 29.0 software (Independent sample t-test, Mann Whitney U-test and Pearson χ2-test). Use repeated measures ANOVA to analyze the time differences and interaction differences of various indicators. Linear regression analysis was used to examine the correlation between CMT, mean GCL thickness, EZ integrity, VDs, FAZ area, and combined injection of DEX with BCVA.
Results: There were no statistically significant differences in gender, age, intraocular pressure, and preoperative indicators between the two groups (P>0.05). Both surgical methods can improve the structure, function, and microcirculation disorders in the macular area. The postoperative BCVA in both groups of patients improved compared to before, and persisted until 6 months after surgery. The trend of CMT changes was highly consistent with BCVA, while the average GCL thickness began to recover at 3 months after surgery. The SCP fovea VDs and FAZ area did not show significant recovery until 6 months after surgery. Both surgical methods showed time differences and interaction differences in the above indicators after surgery (P=0.015), and the combined injection of DEX group performed better within 6 months (P=0.036). Compared to the non combined injection of DEX group, only the combined injection of DEX group showed statistically significant improvement in EZ integrity at 6 months after surgery (P=0.009). However, at 1 year of follow-up, there was no statistically significant difference in BCVA and CMT between the two groups (P≥0.079). The improvement of BCVA within 6 months after surgery is correlated with the improvement of CMT, average GCL thickness, SCP fovea VDs, FAZ area, EZ integrity, and injection of DEX within 6 months after surgery. During this study, no serious ocular or systemic complications such as endophthalmitis, vitreous hemorrhage, or retinal detachment occurred in either group of patients at each follow-up time point.
Conclusions: The efficacy of PPV combined with intravitreal injection of DEX is better within 6 months compared to the non-combined injection of DEX treatment group. There was no significant difference in the improvement of BCVA and CMT after one year of surgery between the combined single injection DEX treatment regimen and the non-combined injection DEX treatment regimen.