A systematic review and meta-analysis of clinical outcomes of small gauge vitrectomy with or without intravitreal antivascular endothelial growth factor agents pretreatment for proliferative diabetic retinopathy

Background: Proliferative diabetic retinopathy (PDR) is a common visual threatening ocular disease, patients with nonclearing vitreous hemorrhage (VH), traction retinal detachment (RD), or extensive fibrovascular proliferation are always in need for surgical treatment. Although several studies reported better surgical outcome in patients underwent surgery after anti-VEGF injection, the effect of anti-VEGF pretreatment for small gauge vitrectomy in PDR patients remains to be elucidated. Objectives: To evaluate the benefits of preoperative anti-VEGF treatment in small gauge vitrectomy for PDR patients. Methods: A comprehensive literature search in PubMed, Embase and the Cochrane Central Register of Controlled Trials was performed to identify relevant studies. Meta-analyses were performed for intraoperative (including intraoperative bleeding, endodiathermy, iatrogenic retinal breaks, surgical time and etc) and postoperative outcome parameters (including best corrected visual acuity (BCVA), postoperative VH, postoperative RD and etc). Results: Ten randomized controlled trials were identified and used for comparing small gauge vitrectomy alone (344 eyes, control group) and small gauge vitrectomy with preoperative anti-VEGF injection (355 eyes). The intraoperative findings showed that the surgical time, the incidence of clinically significant intraoperative bleeding, iatrogenic retinal breaks, silicon oil tamponade and the frequency of endodiathermy were significantly less in the anti-VEGF pre-treated group than in the vitrectomy alone group (p<0.01). The postoperative findings showed that the incidences of early postoperative VH, postoperative RD were significantly less in the anti-VEGF pre-treated group than in the control group (p<0.05), The pooled result of postoperative ubeosis iridis/neovascular glaucoma was borderline (p=0.072) between cases and controls. While No statistically significant differences in BCVA at last follow up and incidences of late postoperative VH were found between these two groups (p>0.05). Conclusions: Anti-VEGF injection prior to small gauge vitrectomy in PDR patients might facilitate easier surgical procedure and reduce intra- and postoperative complications. Further studies are needed to verify our findings and evaluate the optimal interval and dosage for preoperative anti-VEGF injection.