Changes in Retinal Nerve Fiber Layer and Macular Ganglion Cell-Inner Plexiform Layer Thickness after Spinal Surgery in the Prone Position

Abstract

Objective: Postoperative visual loss resulting from posterior ischemic optic neuropathy (PION) after spinal surgery is rare but devastating. A potential risk factor is prolonged spinal surgery in the prone position. We hypothesized that if this risk factor is linked to PION, the retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) should decrease post-surgery. Materials and Methods: The prospective cohort study was conducted in patients undergoing spinal surgery in the prone position. The RNFL and GCIPL thickness by optical coherence tomography before and after spinal surgery (6-week, 3-month post-operative) were analyzed. Results: Nineteen patients (38 eyes) completed the study with three follow-up timepoints. The mean age was 53.78+/-12.71 years. No significant changes were observed in the RNFL thickness and macular ganglion cell-inner plexiform layer changes at the 6 weeks and 3 months follow-ups, except for the RNFL at the inferior quadrant at 6 weeks follow-up. There were also no patients who experienced visual loss. Conclusion: A transient decrease in RNFL thickness in the inferior quadrant was observed at the 6-week postoperative follow-up after spinal surgery. The prone position during surgery may be an intraoperative factor associated with the development of perioperative PION in patients undergoing spinal procedures.