The effect of robotic surgery on intraocular pressure and optic nerve sheath diameter: a prospective study

To investigate the effect of the steep Trendelenburg position (35° to 45°) and carbon dioxide (CO2) insufflation on optic nerve sheath diameter (ONSD), intraocular pressure (IOP), and hemodynamic parameters in patients undergoing robot-assisted laparoscopic prostatectomy (RALP), and to evaluate possible correlations between these parameters.

A total of 34 patients were included in this study. ONSD was measured using ultrasonography and IOP was measured using a tonometer at four time points: T1 (5minutes after intubation in the supine position); T2 (30minutes after CO2 insufflation); T3 (120minutes in steep Trendelenburg position); and T4 (in the supine position, after abdominal exsufflation). Systolic and diastolic arterial pressure, heart rate, and end-tidal CO2 (etCO2) were also evaluated.

The mean IOP was 12.4mmHg at T1, 20mmHg at T2, 21.8mmHg at T3, and 15.6mmHg at T4. The mean ONSD was 4.87mm at T1, 5.21mm at T2, 5.30mm at T3, and 5.08 at T4. There was a statistically significant increase and decrease in IOP and ONSD between measurements at T1 and T4, respectively. However, no significant correlation was found between IOP and ONSD. A significant positive correlation was found only between ONSD and diastolic arterial pressure. Mean arterial pressure, heart rate, and etCO2 were not correlated with IOP or ONSD.

A significant increase in IOP and ONSD were evident during RALP; however, there was no significant correlation between the two parameters.