title: A systematic review and meta-analysis of clinical outcomes of vitrectomy with or without intravitreal bevacizumab pretreatment for severe diabetic retinopathy.
abstract: OBJECTIVE
  To examine possible benefits of intravitreal bevacizumab (IVB) pretreatment in vitrectomy for severe diabetic retinopathy.
  
  
  METHODS
  A comprehensive literature search was performed using the Cochrane Collaboration methodology to identify randomised controlled trials and comparative studies of vitrectomy with or without IVB pretreatment for severe or complicated diabetic retinopathy. Meta-analyses were performed for intraoperative (including intraoperative bleeding, endodiathermy, iatrogenic retinal tears and mean surgical time) and postoperative outcome parameters (including best-corrected visual acuity, recurrent vitreous haemorrhage, reabsorption time of blood and other complications).
  
  
  RESULTS
  Six randomised controlled trials and one comparative study were identified and used for comparing vitrectomy alone (142 eyes, control group) with vitrectomy with IVB pretreatment (139 eyes). The intraoperative findings showed that the incidence of intraoperative bleeding and frequency of endodiathermy were statistically significantly less in the IVB pretreatment group (p<0.01) than in the vitrectomy alone group. The IVB pretreatment group took significantly less surgical time than the control group (p=0.003). Postoperative results indicated that reabsorption time of blood was significantly shorter (p=0.04), incidence of recurrent VH was almost significantly less (p=0.05), and final best-corrected visual acuity was significantly better (p=0.003) in the IVB group than in the control group. Other complications, including final retinal detachment, and reoperation, were statistically insignificant.
  
  
  CONCLUSIONS
  IVB pretreatment in vitrectomy can achieve excellent clinical outcomes for severe diabetic retinopathy. It potentially facilitates surgeons' manoeuvres and reduces intra- and postoperative complications.
authors.affiliation: Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, PR China.
authors.forename: Li-Quan
authors.initials: LQ
authors.lastname: Zhao
authors.forename: Huang
authors.initials: H
authors.lastname: Zhu
authors.forename: Pei-Quan
authors.initials: PQ
authors.lastname: Zhao
authors.forename: Yi-Qian
authors.initials: YQ
authors.lastname: Hu
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D016063:Blood Loss, Surgical / Q000517:prevention & control* / Q000706:statistics & numerical data; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D015994:Incidence; D007432:Intraoperative Period; D058449:Intravitreal Injections; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D012720:Severity of Illness Index; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A; D014821:Vitrectomy / Q000379:methods*
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab