TL;DR: The 2024-2026 evidence base for hyperbaric oxygen therapy (HBOT) in spinal cord injury (SCI) has expanded substantially, anchored by a 2026 systematic review of 50 studies covering 1,102 patients across nearly five decades. Preclinical mechanism studies converge on neuroinflammation, ferroptosis, microglial polarisation, and gut-brain axis pathways. Clinical evidence remains heterogeneous, but signals favour early initiation in incomplete injuries. Canadian researchers should note the persistent gap in standardised, multicentre randomised controlled trials.
Hyperbaric oxygen therapy for spinal cord injury is an adjunctive treatment in which 100% oxygen is delivered at pressures exceeding 1 atmosphere absolute to mitigate secondary ischaemic injury and modulate neuroinflammation. The 2024-2026 publication window has produced a hybrid systematic review, two narrative reviews, and several mechanistic preclinical studies that meaningfully refine the evidence base. This summary synthesises that body of work for Canadian researchers, clinical investigators, and physicians monitoring emerging indications. Citations sourced from PubMed.
Spinal cord injury affects approximately 86,000 Canadians, with around 4,300 new cases each year according to Spinal Cord Injury Canada. Current standard-of-care interventions, including methylprednisolone, surgical decompression, and rehabilitation, leave substantial residual disability. Hyperbaric oxygen therapy has been investigated as an adjunct since the late 1970s, but methodological heterogeneity has prevented definitive efficacy conclusions. Canada Hyperbarics tracks this literature continuously across the research bank.
What Does the Most Recent Systematic Review Say About HBOT for SCI?
The most authoritative 2026 evidence comes from Iaconetta and colleagues, published in Brain Sciences, which conducted a hybrid PRISMA-compliant systematic review covering 50 studies and 1,102 patients across 1978-2024 (PMID 41750166; DOI 10.3390/brainsci16020165). The review separated traumatic spinal cord injury (TSCI) and non-traumatic spinal cord injury (NTSCI) etiologies, an important methodological refinement. Key findings:
- Preclinical evidence is consistently supportive, but clinical data remain heterogeneous across TSCI and NTSCI etiologies.
- Neurological improvement was more frequently observed in incomplete injuries compared to complete injuries.
- Earlier initiation of HBOT correlated with better functional recovery, with most positive trials starting therapy within hours to days of injury.
- Methodological heterogeneity precluded quantitative meta-analysis; only qualitative synthesis was possible.
- The authors concluded HBOT may be a useful adjunct in selected SCI patients, but standardised protocols and controlled trials are still required.
This conclusion echoes the narrative review by Peng and colleagues in Medical Gas Research, which synthesised preclinical and clinical evidence and emphasised that optimal timing, treatment duration, and number of sessions remain unsettled (internal summary; DOI 10.4103/mgr.MEDGASRES-D-24-00111).
What Mechanistic Pathways Are Driving the Preclinical Signal?
2025-2026 mechanism studies have substantially clarified how HBOT might attenuate secondary spinal cord injury. The picture that emerges is multimodal rather than single-pathway:
| Pathway | Effect | Representative 2024-2026 Study |
|---|---|---|
| Nrf2/GPX4 anti-ferroptosis | Reduces hippocampal neuronal ferroptosis, alleviates depression-like behaviour and cognitive impairment | Li et al. 2025, CNS Neurosci Ther |
| STAT3/RORgammaT suppression | Reduces IL-17+ gammadelta T-cell activation and inflammatory cytokines | Liu et al. 2025, J Transl Med |
| Functional and structural plasticity | Restored cortical regional homogeneity on rs-fMRI; improved BBB locomotor scores | Yang et al. 2024, Brain Behav |
| Gut-brain axis | Restored intestinal barrier integrity, modulated microbiota composition, corrected glycerophospholipid metabolism | Liu et al. 2025, J Mol Med |
| Combination with stem-cell exosomes | Synergistic neuronal preservation; reduced TNF-alpha, IL-1beta, MDA | Hjazi et al. 2024, Tissue Cell |
The Nrf2/GPX4 pathway finding is notable because it links HBOT to ferroptosis suppression, an iron-dependent regulated cell death mechanism that has emerged as a major driver of secondary SCI pathology. Li and colleagues used the selective Nrf2 inhibitor ML385 to confirm pathway dependency, providing causal rather than merely correlative evidence (internal summary; DOI 10.1111/cns.70421).
The gut-brain axis result from Liu and colleagues is even more novel: HBOT reversed SCI-induced gut dysbiosis, and antibiotic-induced dysbiosis worsened locomotor recovery in a way that HBOT could partially rescue (internal summary; DOI 10.1007/s00109-025-02604-2). This opens a translational research direction in which the intestinal microbiota becomes a candidate biomarker and therapeutic target alongside HBOT. A separate 2025 paper from the same group identified IL-17+ gammadelta T cells as a specific immunological target through STAT3/RORgammaT modulation (internal summary; DOI 10.1186/s12967-025-07168-w).
How Strong Is the Neuroplasticity Evidence in 2024-2026?
Yang and colleagues used resting-state functional MRI in a rat SCI model to demonstrate that HBOT reverses reductions in regional homogeneity in primary somatosensory cortex, striatum, and limbic regions, while strengthening functional connectivity between motor cortex and the contralateral somatosensory cortex, thalamus, and basal forebrain (internal summary; DOI 10.1002/brb3.70196).
The connectivity changes correlated positively with Basso, Beattie, and Bresnahan locomotor scale scores, which is methodologically meaningful because it links a brain-imaging biomarker to a behavioural endpoint. Histopathology confirmed reduced apoptotic protein expression and increased neuronal counts in the same regions where rs-fMRI signal recovered. This kind of multimodal mechanistic evidence is exactly what the field has lacked.
Combination strategies are also gaining traction. Hjazi and colleagues showed that pairing HBOT with menstrual-blood-derived stem cell exosomes produced larger antioxidant and neuronal-preservation effects than either intervention alone, with significant reductions in TNF-alpha, IL-1beta, and malondialdehyde (internal summary; DOI 10.1016/j.tice.2024.102378).
What Are the Persistent Methodological Gaps?
Despite the 2024-2026 progress, the literature still suffers from problems first identified by Siglioccolo and colleagues in their 2023 narrative review, which proposed an evidence-based protocol flowchart specifically to address them (internal summary; DOI 10.1016/j.cjtee.2023.05.002). The persistent gaps:
- No standardised treatment protocol. Pressure (typically 2.0 to 2.5 atmospheres absolute), session duration (60 to 120 minutes), session count (10 to 60), and timing of initiation vary widely across reported studies.
- Insufficient sample size in most clinical trials. Most positive clinical reports come from single-centre case series rather than adequately powered randomised trials.
- Inconsistent outcome measurement. Endpoints range from ASIA Impairment Scale to Frankel grade to bespoke functional indices, complicating cross-study synthesis.
- Limited stratification by SCI completeness, level, and chronicity. Effect size likely differs substantially between acute incomplete cervical injuries and chronic complete thoracic injuries, but the literature rarely separates these populations cleanly.
- Almost no Canadian-led RCTs. Most clinical data originate from China, Italy, and Russia, with limited representation from Canadian or other Anglophone academic centres.
Alqasmi and colleagues, writing in eNeurologicalSci in March 2026, frame these gaps as an opportunity rather than a deal-breaker: HBOT remains a viable therapeutic option pending validation, with mechanism-of-action research now mature enough to inform protocol design (internal summary; DOI 10.1016/j.ensci.2026.100608).
What Is the Regulatory and Clinical Status in Canada?
SCI is not currently a Health Canada or Undersea and Hyperbaric Medical Society (UHMS) recognised indication for hyperbaric oxygen therapy. The UHMS list of recognised indications, last revised in the 15th Edition Indications Manual, does not include traumatic or non-traumatic spinal cord injury. Provincial public health insurance plans across Canada accordingly do not cover HBOT for SCI in routine clinical practice. The full UHMS indications list is published by UHMS.
For Canadian researchers planning trials, the practical implication is that any prospective study will need to operate under a Health Canada Clinical Trial Application or as an off-label investigational protocol. The CIHR and Praxis Spinal Cord Institute remain the most likely funders for a Canadian-led HBOT-SCI investigation. Canada Hyperbarics maintains a directory of hospitals and regulated facilities with hyperbaric capability, several of which are research-active.
What Are the Priority Research Questions for 2026 and Beyond?
Based on the 2024-2026 literature, four research questions deserve priority attention:
- What is the optimal therapeutic window? Animal and observational human data suggest initiation within hours to days produces larger effects than chronic-phase initiation, but no head-to-head trial has stratified by time-to-treatment.
- Does HBOT add value to surgical decompression and methylprednisolone, or is it a substitute pathway? Combined-modality protocols have not been rigorously tested.
- Are mechanistic biomarkers, including microbiome composition, ferritin, GPX4, and rs-fMRI connectivity indices, useful for predicting responders? Yang et al. (2024) and Liu et al. (2025) provide proof-of-concept data.
- What is the cost-effectiveness profile in a Canadian health-system context? No published Canadian economic analysis exists.
Researchers focused on neuropsychiatric sequelae of SCI, particularly post-injury depression, may also find the Cotter et al. 2024 systematic review of behavioural and pharmacologic interventions a useful comparator (internal summary; DOI 10.1016/j.apmr.2024.01.004). The Li et al. 2025 finding that HBOT alleviates depressive-like behaviour through Nrf2/GPX4 modulation positions HBOT as a candidate for combined trials with venlafaxine or mindfulness-based intervention.
Frequently Asked Questions
Is HBOT a UHMS-recognised indication for spinal cord injury?
No. The UHMS recognised-indications list, currently in its 15th Edition, does not include traumatic or non-traumatic spinal cord injury. SCI is treated as an investigational or off-label indication.
Does provincial public health insurance cover HBOT for SCI in Canada?
Generally no. Provincial plans, including OHIP in Ontario, MSP in British Columbia, AHCIP in Alberta, RAMQ in Quebec, and others, do not cover HBOT for SCI as a routine indication. Coverage is restricted to Health Canada and UHMS-recognised indications. Research participation under a Health Canada Clinical Trial Application is the typical pathway for funded access.
What does the most recent meta-analysis show?
The 2026 hybrid systematic review by Iaconetta et al. did not perform a quantitative meta-analysis because of methodological heterogeneity across the 50 included studies. Qualitative synthesis suggested benefit was more frequently observed in incomplete injuries and with earlier initiation, but pooled effect sizes are not available.
What pressure and session protocol is most commonly used in SCI research?
Most reported protocols use 2.0 to 2.5 atmospheres absolute for 60 to 120 minutes per session, with 10 to 60 sessions over weeks to months. Siglioccolo et al. 2023 proposed a flowchart aimed at standardising future trials, but no consensus protocol exists.
Is HBOT effective for chronic complete spinal cord injury?
The available evidence does not support a meaningful effect in chronic complete injuries. Most positive clinical signals come from acute or subacute incomplete injuries treated within days to weeks of insult. Patients with chronic complete injuries should not be told to expect functional recovery from HBOT based on current data.
Are there ongoing Canadian clinical trials of HBOT for SCI?
As of 2026, no actively recruiting Canadian-led randomised controlled trial of HBOT for SCI is registered on ClinicalTrials.gov or the Health Canada Clinical Trials Database. Researchers interested in this gap should consider the Praxis Spinal Cord Institute and CIHR as potential funders.
What are the contraindications to HBOT in SCI patients specifically?
SCI patients carry the same absolute and relative contraindications as the general HBOT population: untreated pneumothorax, certain chemotherapy agents, severe COPD with bullae, and others. SCI-specific concerns include autonomic dysreflexia precipitated by chamber pressure changes and the need for adapted patient transfer in monoplace systems. Each patient requires individual screening before enrolment.
Where can clinicians and researchers find further reading?
Canada Hyperbarics maintains the largest indexed database of HBOT research in Canada, with searchable summaries and direct PubMed links. The research bank includes all studies referenced in this review and is updated continuously from PubMed.
Conclusion: Where the Field Stands in 2026
The 2024-2026 evidence has moved HBOT for spinal cord injury from a thinly supported off-label option to a mechanistically plausible adjunct with consistent preclinical signal and a heterogeneous but suggestive clinical signal. The key barrier to broader adoption is no longer mechanism but methodology. A protocol-standardised, adequately powered, multicentre randomised trial stratified by injury completeness and time-to-initiation would resolve much of the remaining uncertainty.
For Canadian researchers, the funding case for such a trial is strengthening as mechanistic evidence accumulates. Canada Hyperbarics will continue to track this literature and surface emerging trials through the research bank. Clinicians considering referral or research participation can locate appropriate hospitals and regulated facilities through the directory.
This content is for informational purposes only and does not constitute medical advice. Hyperbaric oxygen therapy for spinal cord injury is not currently an approved indication in Canada. Patients should consult a qualified physician for individual clinical guidance, and researchers should consult Health Canada regarding investigational use.