title: Intraoperative complications of patients undergoing small-gauge and 20-gauge vitrectomy: a database study of 4,274 procedures.
abstract: OBJECTIVE
  To compare the intraoperative complications between 23-G and 20-G instrumentation in patients undergoing pars plana vitrectomy (PPV).
  
  
  METHODS
  This was a retrospective comparative study of 4,274 PPV procedures by the same surgical team between 1998 and 2016. A total of 2,648 operations were carried out with 20-G surgery and 1,626 operations with 23-G surgery. Main outcome measures were the incidence of choroidal haemorrhage, iatrogenic retinal break, and lens touch.
  
  
  RESULTS
  The most frequent surgical indication in both 20-G and 23-G was rhegmatogenous retinal detachment (RRD), 38.7% (1,026/2,648) and 45.9% (746/1,626), respectively. The frequency of choroidal haemorrhage was 1.0% with 20-G surgery (26/2,648) vs 0.6% with 23-G (9/1,626, p = 0.16). Subgroup analysis showed the increased risk was present in RRD surgery, 1.6% (16/1,026) vs 0.1% (1/746, p = 0.002), but not in all other indications combined, 20-G with 0.6% (10/1,622) and 23-G 0.9% (8/88, p = 0.46). This increased risk was also true for RRD when excluding combined scleral buckle surgery. There was an increased risk of iatrogenic retinal break in RRD cases undergoing 20-G, 5.8% (60/1,026), compared to 23-G vitrectomy, 1.9% (14/746, p<0.0001). There was no difference in rates of lens touch between 20-G and 23-G.
  
  
  CONCLUSIONS
  23-G microincisional PPV has a lower risk of choroidal haemorrhage and iatrogenic retinal tears than 20-G vitrectomy particularly for eyes with RRD.
authors.affiliation: Department of Ophthalmology, Royal Berkshire Hospital, Reading - UK.
authors.forename: James E
authors.initials: JE
authors.lastname: Neffendorf
authors.affiliation: Department of Ophthalmology, Royal Berkshire Hospital, Reading - UK.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Gupta
authors.affiliation: Department of Ophthalmology, St. Thomas' Hospital, London - UK.
authors.forename: Tom H
authors.initials: TH
authors.lastname: Williamson
mesh_terms: D000328:Adult; D000368:Aged; D002832:Choroid Hemorrhage / Q000209:etiology; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D007431:Intraoperative Complications / Q000209:etiology; D007905:Lens Diseases / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012164:Retinal Diseases / Q000601:surgery*; D012167:Retinal Perforations / Q000209:etiology; D012189:Retrospective Studies; D012591:Scleral Buckling / Q000379:methods; D014792:Visual Acuity; D014821:Vitrectomy / Q000009:adverse effects / Q000379:methods; D014823:Vitreous Hemorrhage / Q000601:surgery*