Evaluation of predictive factors associated with increased intraocular pressure during prone position spine surgery

Intraocular pressure(IOP) has been shown to increase during prone position spine surgery. The present study was conducted to evaluate IOP changes and predictive factors associated with increased IOP during prone position spine surgery.

After institutional approval and written informed consent, 56 patients undergoing prone position spine surgery were studied. Anesthesia was maintained with propofol or sevoflurane, remifentanil, and fentanyl. IOP was measured using a Tono-Pen XL hand-held tonometer 10 min after induction of anesthesia, every 60 min after prone positioning, and 10 min after returning to the supine position. According to maximum IOP, patients were divided into group H with a maximum IOP value of ≥30 mmHg or group L with a maximum IOP value of <30 mmHg. Logistic regression analyses were performed to identify predictive factors associated with increased IOP.

Maximum IOP values ranged from 19-40 mmHg and 20 patients were included in group H. There were no statistically significant differences in demographic and intraoperative variables between the two groups. IOP 1 h after prone positioning (IOP1H) was significantly higher in group H than in group L. Logistic regression analysis revealed that IOP1H of ≥23 mmHg was a significant predictor (odds ratio 19.0, 95 % C.I 3.7-97.6).

IOP1H values may be used as a predictive factor associated with increased IOP during prone position spine surgery.