Effects of 25- and 30-degree Trendelenburg positions on intraocular pressure changes during robot-assisted radical prostatectomy

BACKGROUND: The objective of this study was to assess the effects of 25-degree and 30-degree Trendelenburg positions on intraocular pressure (IOP) changes during robot-assisted radical prostatectomy (RARP). MATERIALS AND METHODS: This prospective study involved a total of 30 consecutive patients undergoing RARP. All participants were randomly divided into two groups: Trendelenburg position with the head down at 25 degrees or 30 degrees. In addition to representative operative outcomes, IOP was measured at six discrete time points; Time 1 (T1): before induction of general anesthesia, patients in a horizontal supine position; T2: after induction of general anesthesia, patients in a horizontal supine position; T3: 1 hour after adopting the Trendelenburg position; T4: 2 hours after adopting the Trendelenburg position; T5: after pneumoperitoneum resolution in the Trendelenburg position; T6: anesthetized before awakening in a supine position. RESULTS: The total and console operative times, estimated blood loss, and intravenous fluid intake during RARP did not significantly differ between the two groups. While the IOP values measured at the same time points were similar between the two groups, the 25-degree Trendelenburg position significantly attenuated the IOP change from T1 to T3, T4, and T5 compared with those at 30 degrees. CONCLUSIONS: These findings suggest that RARP in the 25-degree Trendelenburg position may reduce the risks of position-related ophthalmic complications without increasing the difficulty of the surgical procedure.