Abstract
Purpose :
Postoperative visual field (VF) defects and vision loss secondary to intraocular pressure (IOP) spikes have been reported with robot-assisted radical laparoscopic prostatectomy (RALP) in steep Trendelenburg position (sTBURG). This study evaluated the effect of preoperative brimonidine on IOP during RALP in sTBURG.
Methods :
In this prospective randomized controlled masked interventional trial (# NCT02818816), patients scheduled for RALP in sTBURG at University Health Network were screened. Exclusion criteria included diagnosis of glaucoma or ocular hypertension. With informed consent, subjects were randomized to right or left eye. Study eyes were randomized to placebo (artificial tears) or drug (brimonidine tartrate 0.2%) preoperatively. Comprehensive eye exam was done preoperatively and 1-month postoperatively including visual acuity (VA), tonometry, disc photography, VF and retinal nerve fiber layer (RNFL) assessments. A standardized anesthesia protocol was followed intraoperatively. Tono-Pen IOP measurements were recorded bilaterally as follows: pre-anesthesia, anaesthetized supine, hourly in sTBURG and awake supine. The mean of 3 IOP readings each within 2 mmHg was recorded with 5% confidence interval. Primary outcome was IOP. Secondary outcomes were changes in VA, VF and RNFL. Planned sample size is 26 subjects. Study was approved by University Health Network Research Ethics Board.
Results :
To date, 5 of 7 recruited patients completed the study (2 brimonidine, 3 placebo). Significant IOP elevation was noted in control, placebo & drug treated eyes at 1 hour of sTBURG. IOP remained elevated during sTBURG. Mean IOP during sTBURG was 31.4±3.6, 30.8±2.4 and 35.9±6.7 mmHg in control, placebo and drug treated eyes respectively, p=0.11 for drug versus placebo. Highest IOP recorded was 44 mmHg at 1 hour of sTBURG, an IOP spike of 30 mmHg from baseline in a drug treated eye. IOP returned to baseline in 8 of 10 eyes 30 minutes after supine positioning. No significant changes were noted in VA, VF or RNFL.
Conclusions :
Significant, sustained IOP increase occurs during sTBURG. Early data suggests preoperative brimonidine may not prevent IOP spikes. Enrolment is ongoing.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.