# Ocular Safety of Unilateral Biportal Endoscopic Spinal Surgery: An Optical Coherence Tomography Angiography-Based Analysis

## TL;DR

This study uses OCTA to assess the ocular safety of UBE spinal surgery and finds no clinical vision loss or lasting retinal changes.

## Contribution

The study is the first to use OCTA to evaluate retinal microvascular changes after UBE surgery.

## Key findings

- No patients experienced clinical vision loss after UBE surgery.
- Some OCTA parameters showed temporary changes, but most returned to baseline.
- VDd superior was the only parameter with a significant decrease at week 4.

## Abstract

Background: UBE has gained popularity as a minimally invasive alternative to open spinal procedures. However, it raises concerns about potential ocular complications. Despite these concerns, there is a lack of studies evaluating UBE’s impact on retinal microvasculature using objective imaging tools such as OCTA. This study aims to evaluate the effects of UBE on the microvascular structures of the retina and optic nerve using OCTA, and to determine whether UBE poses a risk for perioperative vision loss. Methods: This study included 32 patients who underwent UBE for lumbar stenosis and received ophthalmologic examinations preoperatively, and at postoperative weeks 1 and 4. Patients with systemic or ocular vascular comorbidities were excluded. OCTA parameters including vascular density (VD), foveal avascular zone (FAZ), retinal nerve fiber layer (RNFL), central macular thickness (CMT), and subfoveal choroidal thickness (SFCT) were evaluated using swept-source OCT. Results: No patients experienced clinical vision loss. A statistically significant change was observed over time in FAZ (p = 0.043), VDd superior (p = 0.018), VDd temporal (p = 0.032), and RNFLts (p = 0.032). However, only VDd superior showed a statistically significant decrease at postoperative week 4 compared to baseline (p = 0.050). All other parameters either returned to baseline or showed no significant change. No clinically relevant visual changes were detected. Conclusions: In this study, UBE spinal surgery was not associated with clinically evident visual loss or sustained OCTA-detected microvascular alterations during short-term follow-up. These findings should be interpreted as reflecting the absence of detectable short-term changes rather than definitive evidence of ocular safety.