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AIM: To identify the risk factors for postoperative proliferative vitreoretinopathy (PVR) in patients with primary rhegmatogenous retinal detachment (RRD) and develop a nomogram for predicting postoperative PVR-free probability. METHODS: A total of 741 patients (741 eyes) diagnosed with primary RRD who underwent first surgery in the same hospital were retrospectively reviewed and randomly assigned with 521 to the training set and 220 to the validation set. Univariate and multivariate logistic regression analyses were performed in the training cohort to determine risk factors to construct a nomogram for predicting the 3-, 4-, 5-, and 6-month postoperative PVR-free probabilities. Nomogram performance was estimated by the concordance index (C-index), calibration plot, and the area receiver operating characteristic (ROC) curve. RESULTS: A nomogram was constructed based on the preoperative PVR, silicone oil tamponade time (SOTT), photocoagulation energy (PE), retinal tear size (RTS), and hypertension. In the training set, the C-index of the nomogram was 0.896, 0.936, 0.961, and 0.972 at 3, 4, 5, and 6mo, respectively. The C-index values in the validation set were 0.860, 0.936, 0.951, and 0.965 at 3, 4, 5, and 6mo, respectively. Decision-curve analysis indicated that only the 4-, 5-, and 6-month nomograms had significant net benefits over a large threshold probabilities interval. CONCLUSION: Preoperative PVR, SOTT, PE, RTS, and hypertension are significant risk factors for postoperative PVR formation in patients with primary RRD. The proposed nomogram can effectively predict the 4-, 5-, and 6-month PVR-free probabilities after surgery and assist in making clinical decisions during follow-up.
RESUMO
Purpose. To report a new approach for removal of silicone oil. Methods. All surgeries were performed using 23-gauge vitrectomy system with two transconjunctival sutureless cannulas. At the beginning, most of the silicone oil was removed by traditional microinvasive vitrectomy system through inferior-temporal cannula. Then, the blood transfusion tube is removed from the inferior-temporal cannula, and the fluid-air exchange is performed. A passive fluid-air exchange was performed to aspirate the residual silicone oil after gradually turning the patient's head temporally by approximately 90° gradually. Results. After the surgery, all patients had a clear anterior chamber and vitreous cavity on slit lamp and B scan examination, respectively. The mean time taken for silicone oil removal and total surgery was 8.0 ± 1.4 minutes and 12.4 ± 2.5 minutes, respectively. The mean intraocular pressure 1 day, 3 days, 1 week, 1 month, and 3 months after surgery was 9.0 ± 5.8 mmHg, 11.3 ± 7.6 mmHg, 16.1 ± 6.9 mmHg, 17.7 ± 4.8 mmHg, and 17.1 ± 3.5 mmHg, respectively. Conclusion. This new approach may provide a safe and fast method to remove the silicone oil.
