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What causes delayed spinal cord injury?

Michael G Millin, Johanna C Innes, Gregory D King, Benjamin N Abo, Seth M Kelly, Curtis L Knoles, Robert Vezzetti, Chelsea C White, Allen Yee & John M Gallagher (30 Jul 2025): Prehospital Trauma Compendium: Prehospital Management of Spinal Cord Injuries – A NAEMSP Comprehensive Review and Analysis of the Literature, Prehospital Emergency Care DOI:10.1080/10903127.2025.2541258

Accessible at: https://www.tandfonline.com/doi/pdf/10.1080/10903127.2025.2541258

Scenario 

A walker falls 30 meters down slope in winter.  They have some painful ribs, but can walk. It is windy and cold a sunset is in 1 hour.  You recall a clinical algorithm suggesting that any fall > 1 m is high risk for spinal cord injury and requires full spinal immobilisation. You wonder what the evidence is that movement is the main cause of delayed spinal cord injury?

Introduction

Is movement the cause of delayed spinal cord injury (DSCI) following trauma?  This statement challenges the principle underpinning the pre-hospital treatment of spinal column injury. The assumption that movement causes DSCI has dictated an approach based on spinal immobilisation.  In the last decade, the absence of evidence for this assumption and the recognition that such practice can have negative consequences have modified our approach.  We are now more comfortable with allowing self-mobilisation, no longer applying a rigid collar to all patients and referring to motion limitation rather than immobilisation.  But all these actions continue to assume that movement is the cause of DSCI. This paper reviews the basis for this assumption and presents a paradigm shift in our understanding of spinal cord injury.  

What did they do?

The authors conducted a structured literature review around 4 research questions:

1. What are the underlying pathophysiological causes of the phenomenon of delayed neurological injury in the setting of trauma, with a focus on movement, hypoxia, and hypoperfusion?

2. Does the use of a backboard or cervical collar result in patient-oriented harms, with a focus on the formation of decubitus ulcers, developing respiratory depression, causing increased intracranial pressure, or direct harm to the nervous system?

3. Are backboards and cervical collars effective at preventing delayed neurologic injury or immobilising the spinal column as intended?

4. Are there other factors that may affect the utility of backboards and cervical collars, such as patient anxiety, patient anatomy, patient age, or environmental conditions?

3844 papers were identified, and of these, 115 were suitable for the focused review.

What did they find?

The paper discusses the outcome of all four research questions.  Here, we focus on the first, which provides the foundation for understanding our initial management of suspected spinal column injury. 

Q1.What are the underlying pathophysiological causes of the phenomenon of delayed neurological injury in the setting of trauma, with a focus on movement, hypoxia, and hypoperfusion?

The authors identified two historic case series suggesting that DSCI was caused by movement after the initial injury.  All 11 cases were from an era before detailed imaging and were based on subjective opinions voiced during interviews or non-robust clinical data.  They found no evidence in the literature that DSCI was caused by movement. 

In contrast, they identified several studies which demonstrated an association between DSCI and hypotension. Mean arterial pressure is directly linked to neurological outcome in spinal cord injury.  An increase of 10 mmHg leads to an increase of 79% in the odds of an improved outcome.  Another study showed that minimising pre-hospital hypotensive episodes (<80mm Hg) was associated with an improved neurological outcome at one year. 

The literature also identified pathologies such as cord oedema, contusion, epidural haematoma and vascular injury as causes of evolving spinal cord injury.  None of these would have been considered at the time before MRI scanning was available.

They found that the evidence supporting the hypothesis that delayed SCI was related to spinal cord hypoperfusion and systemic hypoperfusion was greater than the hypothesis that it was caused by post-injury movement. 

The conclusion of the paper summarises the findings as follows:

"Despite historical precedent, there is no literature demonstrating a clinical benefit to spinal motion restriction. In fact, efforts to restrict movement cause harm and may have a paradoxical effect. The pathophysiology underlying the development of delayed neurological deficits in the setting of trauma, if this pathology exists, is likely multi-factorial. EMS clinicians should focus on the management of shock and hypoperfusion. Efforts aimed to reduce the use of cervical collars should be considered, and the use of backboards and full body vacuum splints should be limited to the point in time of active patient extrication. Given the lack of data supporting clinical benefit, and the extent of data demonstrating the evidence of harm, spinal immobilisation, and SMR, should not continue to be upheld as standard of care".

Why this paper is useful

This paper provides evidence for a change in focus in pre-hospital spinal care.  In the mountains, the decision to perform spinal motion restriction has significant consequences for resource management, a prolonged or more technical evacuation and the continued exposure to the environment for both the patient and rescuers.  This can distract from other essential treatment and delay transfer to definitive care. The harms associated with SMR are all features of evacuation from the mountains.  This paper allows us to reconsider our priorities for care and avoid interventions which may have little or no benefit. 

Will this paper change your management? 

Why not drop a note in the comments box for other members of the mountain medicine community to read?