Spinal surgery patients rarely expect to wake up with vision loss. Yet for a 53-year-old man undergoing posterior atlantoaxial reduction and internal fixation at a Chinese tertiary hospital in October 2025, this nightmare became reality. A case report published in BMC Anesthesiology on June 26, 2026 documents how delayed hyperbaric oxygen therapy (HBOT)—initiated more than 50 hours after symptom onset—salvaged meaningful vision in a scenario where conventional reperfusion strategies were contraindicated.
The report highlights a rare but serious complication of prone positioning during cervical spine procedures, while simultaneously demonstrating that HBOT’s therapeutic window for central retinal artery occlusion (CRAO) may extend well beyond the traditionally cited 24-hour limit.
The Incident: From Routine Surgery to Hand-Motion Vision
The patient presented with atlantoaxial subluxation—a potentially dangerous misalignment of the top two cervical vertebrae—requiring surgical stabilization. The procedure, performed under general anesthesia in the prone position, proceeded without hemodynamic instability. Yet when the patient was returned to supine position and extubated, troubling signs emerged.
A pressure mark and erythema were noted over the right orbit, suggesting direct compression during the procedure. The patient reported blurred vision in that eye. Ophthalmological examination revealed hand-motion visual acuity, a reduced pupillary light reflex, and the classic funduscopic findings of CRAO: posterior pole retinal edema with a cherry-red spot at the macula. Fluorescein angiography confirmed delayed retinal vascular filling consistent with arterial occlusion.
The mechanism appears straightforward in retrospect. Prone positioning for posterior cervical spine surgery places the patient’s face in direct contact with the operating table or headrest. Improper positioning, excessive pressure, or prolonged compression can compromise orbital perfusion through multiple pathways: direct compression of the globe, impaired venous drainage, and reduced arterial inflow. The result is ischemia of the inner retinal layers, which are exquisitely sensitive to oxygen deprivation.
Why Standard Treatments Failed
CRAO represents an ocular emergency analogous to cerebral stroke. The retina consumes oxygen at the highest rate of any tissue in the body—13 mL per 100 grams per minute—and retinal neurons begin irreversible damage within 90 to 240 minutes of complete ischemia. Without intervention, fewer than 2% of patients recover baseline vision.
Standard management of acute CRAO includes immediate supplemental oxygen, ocular massage to potentially dislodge emboli, intraocular pressure reduction, and—when available—intra-arterial thrombolysis or endovascular intervention. However, this patient faced a conundrum that perioperative CRAO cases often encounter: the postoperative context made conventional reperfusion strategies either relatively contraindicated or unlikely to help.
Thrombolysis carries significant bleeding risk in the immediate postoperative period, particularly after spinal instrumentation. Endovascular intervention was deemed unlikely to provide meaningful benefit given the clinical presentation. The patient received initial conservative measures, but visual function remained severely impaired.
The HBOT Intervention: Delayed but Effective
Approximately 52 hours after the first postoperative visual complaint—well beyond the conventional therapeutic window—HBOT was initiated. The patient received daily sessions at 2.0 atmospheres absolute (ATA), totaling 14 treatments.
The results, while not complete, were clinically meaningful. Best-corrected visual acuity improved to 20/25 in the affected eye. Serial retinal imaging demonstrated structural improvement consistent with the functional gains. The outcome was not perfect: severe visual field loss persisted with only slight interval improvement, suggesting irreversible damage to portions of the retina despite the therapy.
This case contributes to a growing body of literature challenging rigid time-based exclusion criteria for HBOT in CRAO. While the Undersea and Hyperbaric Medical Society recommends treatment initiation within 24 hours for optimal outcomes, multiple case reports and small series have documented visual improvement with delayed therapy, particularly in subgroups with preserved cilioretinal artery circulation or incomplete occlusion.
The Evidence Base: HBOT for CRAO
The FDA approved HBOT for central retinal artery occlusion in 2006, recognizing it as one of the few interventions capable of salvaging vision in this otherwise devastating condition. The mechanism is well-established: hyperbaric oxygen increases the dissolved oxygen content of plasma sufficiently to maintain retinal viability through diffusion from the choroidal circulation, bypassing the occluded retinal artery until spontaneous recanalization occurs—typically within 72 hours.
StatPearls’ 2024 review of hyperbaric treatment for CRAO summarizes the prognostic data. Patients treated within 8 hours of symptom onset have an 83% chance of improving by 3 or more lines on the Snellen chart. A report on 39 CRAO patients noted 72% improvement with an average of 5 lines of visual acuity gain. However, the review also acknowledges that delayed treatment—while less predictably effective—can still yield meaningful results in selected cases.
The UHMS assigns HBOT for CRAO a Level IIB recommendation, indicating that the evidence supports its efficacy though the data derive from non-randomized studies. This places it among the most strongly supported indications for hyperbaric medicine, particularly given the absence of alternative treatments with comparable efficacy.
Prevention and Recognition
The case underscores the importance of prevention. Perioperative visual loss in spine surgery, while rare, carries devastating consequences. The American Society of Anesthesiologists and other professional societies have published guidelines emphasizing proper positioning, regular assessment of pressure points, and limitation of operative time in prone positions.
Early recognition is equally critical. Anesthesiologists and surgeons must maintain vigilance for orbital compression signs, and postoperative visual complaints require immediate ophthalmological evaluation. The window for effective intervention, while not as narrow as once believed, remains time-sensitive.
Regulatory Context and Safety Considerations
HBOT for CRAO represents an FDA-cleared indication, distinct from the wellness and longevity applications that have generated recent regulatory attention. The 2025 FDA safety letter regarding hyperbaric devices emphasized proper operator training, adherence to manufacturer protocols, and fire prevention—concerns relevant to all HBOT applications but particularly salient given the high oxygen concentrations and pressure differentials involved.
Patients seeking HBOT for CRAO or other FDA-cleared indications should ensure treatment at UHMS-accredited facilities with appropriate medical oversight. The therapy, while generally safe, carries risks including barotrauma, oxygen toxicity seizures, and confinement anxiety that require proper screening and monitoring.
Conclusion
This 2026 case report illustrates both the risks inherent in complex spinal surgery and the therapeutic potential of HBOT for central retinal artery occlusion. While the patient’s outcome was not perfect—significant visual field loss persisted—the restoration of functional central vision from hand-motion acuity to 20/25 represents a meaningful quality-of-life improvement that would have been impossible without hyperbaric intervention.
For clinicians, the case reinforces the importance of positioning vigilance during prone procedures and the need to consider HBOT even when treatment initiation is delayed. For patients, it offers a reminder that sudden painless vision loss constitutes a medical emergency requiring immediate evaluation, and that HBOT—when applied appropriately—remains one of the few effective treatments for this devastating condition.
As research continues to refine our understanding of HBOT’s therapeutic window and optimal protocols for CRAO, cases like this contribute valuable real-world evidence that can inform both clinical practice and future guideline development.
Sources
- Tang et al. — Perioperative central retinal artery occlusion after prone posterior cervical spine surgery treated with delayed HBOT (BMC Anesthesiology, 2026)
- StatPearls — Hyperbaric Treatment of Central Retinal Artery Occlusion (NCBI Bookshelf, 2024)
- FDA — Hyperbaric Oxygen Therapy: Get the Facts
- FDA — Follow Instructions for Safe Use of HBOT Devices (2025 Safety Letter)
- UHMS — Hyperbaric Oxygen Therapy Indications (15th Edition)