Retinal detachment repair by vitrectomy: Simplified formulae to estimate the risk of failure

Aim: Devise simplified formulae, using preoperative clinical data, to give risk estimates of (1) failure and (2) proliferative vitreoretinpathy (PVR) following primary retinal detachment repair by vitrectomy. Methods: 641 patients were analysed as part of an RCT investigating use of 5-fluorouracil and low-molecular-weight heparin. Treatment status had no effect on success rates and did not therefore form part of the analyses. Preoperative risk factors for surgical failure and for PVR within 6 months of retinal detachment surgery were identified, and a multiple variable logistic regression model developed. Further analyses were performed to devise a simple points system to produce risk estimates of failure. Results: Three risk factors were related to failure - previous lens extraction (p=0.046), grade C PVR (p=0.039) and extent of detachment (p<0.001). Three risk factors were also related to failure due to PVR - vitreous haemorrhage (p=0.088), grade C PVR (p=0.044) and extent of detachment (p