Compressive Spinal Emergencies

Noninflammatory Causes of Spinal Cord Compression

Degenerative disease, particularly in the cervical spine, is the most common cause of extrinsic compression in the acute setting, with contributing factors including spinal degenerative changes, disc herniations, and malalignment, which may be accentuated by congenitally short pedicles 1, 2
Epidural hematoma can occur after minor trauma or spontaneously, especially in patients on anticoagulation, and may present with local or radicular pain and progressive neurological deficits 3, 4
Vertebral fractures with retropulsion, such as osteoporotic or pathologic fractures, can lead to myelopathy even with minor trauma or no obvious history of trauma 1, 5
Traumatic spinal injuries, including fractures, subluxation, and dislocation, can cause cord compression and are classified according to the AO Spine Thoracolumbar Injury Classification System based on injury morphology and neurological status 6, 7, 8
Postoperative complications, such as seromas, pseudomeningoceles, hematomas, and/or epidural abscesses, can develop throughout the postoperative course and cause extrinsic compression 1
Neoplastic compression, including primary or metastatic tumors of the extradural and intradural extramedullary spaces, can encroach upon the spinal canal and cause acute or progressive myelopathy 1, 5
Epidural abscess is an infectious process in the epidural space that can cause cord compression, often accompanied by fever and elevated inflammatory markers 1

Vascular Causes of Spinal Cord Compression

Spinal cord ischemia, though infrequent, can result from atheromatous disease, aortic surgery complications, systemic hypotension, thoracoabdominal aneurysms or dissection, sickle cell disease, and spinal arteriovenous malformations (AVMs) 1, 2
Hematomyelia is a rare condition where patients may develop intramedullary hemorrhage from an AVM or spinal artery aneurysm rupture 1
Fibrocartilaginous embolic disease can cause acute ischemic myelopathy 1

Inflammatory Causes of Spinal Cord Compression

Demyelinating diseases, including multiple sclerosis (MS), neuromyelitis optica (NMO), and acute disseminated encephalomyelitis (ADEM), can cause spinal cord compression 1, 2
Systemic inflammatory conditions, such as systemic lupus erythematosus, Sjogren syndrome, mixed connective tissue disorder, Behcet disease, and sarcoidosis, can also cause spinal cord compression 1

Clinical Presentation and Diagnosis

Imaging, particularly MRI, is the gold standard for evaluation of spinal cord compression, offering superior soft-tissue resolution and multiplanar capability 1, 2
CT imaging is useful in trauma settings to detect fractures, subluxation, and dislocation requiring immediate stabilization 3, 4

Management Considerations

A multidisciplinary approach, including coordination between interventional radiology, surgery, and radiation oncology, is often required for the management of pathologic fractures 5

Ruling Out Spinal Cord Compression in Neurological Patients

Initial Assessment and Imaging Selection

The American College of Radiology recommends MRI without and with IV contrast for evaluating suspected spinal cord compression, with a sensitivity of 96% and specificity of 94%, providing optimal depiction of the intraspinal contents including the epidural space and spinal cord 9
The American College of Radiology states that CT is excellent for identifying fractures and bony abnormalities but is significantly inferior to MRI in identifying soft-tissue pathologies that can cause neurologic deficits and require surgical intervention 10, 11
The American College of Radiology advises that plain radiographs are insensitive for evaluation of the epidural space and spinal cord compression, making them inadequate as the initial imaging examination in patients presenting with neurologic compromise 9

MRI Protocol Considerations

The American College of Radiology suggests that MRI should include T2-weighted images and gradient-echo sequences to best display compression of the cord by disc herniation, bone fragments, and hematomas 11
The American College of Radiology recommends that when IV contrast is utilized, comparing pre-contrast and post-contrast MRI sequences is essential to identify abnormal enhancement patterns that may indicate infection, inflammation, or neoplasm 12

Special Considerations

In trauma settings, the American College of Radiology prefers CT as the initial modality for detecting fractures, subluxation, and dislocations requiring immediate stabilization, but MRI should follow if there is clinical concern for cord compression 10, 13
The American College of Radiology suggests that when MRI is contraindicated or unavailable, CT myelography can be performed to assess for traumatic spinal canal narrowing due to disc herniation or epidural hematoma 10, 13
For suspected spinal infections with neurologic compromise, the American College of Radiology recommends MRI without and with IV contrast on an emergent basis, especially in patients with risk factors and elevated inflammatory markers 9

Imaging Modalities for Spinal Cord Compression

Primary Imaging Modality

The American College of Radiology recommends MRI for all patients with suspected spinal cord compression due to its superior soft-tissue resolution and ability to directly visualize the spinal cord, nerve roots, disc material, hematomas, and bone fragments causing compression 14
MRI characterizes the cause of myelopathy, including disc protrusion, hematoma, bone fragments, tumor, or infection 14
MRI assesses the severity of cord injury, including the extent of intramedullary hemorrhage, length of edema, and evidence of cord transection, which helps predict outcomes 14
MRI evaluates ligamentous instability that may not be apparent on CT imaging 14

Alternative Imaging When MRI is Unavailable or Contraindicated

CT myelography is the second-line option when MRI is contraindicated or unavailable, and can assess spinal canal narrowing and cord compression, but is significantly inferior to MRI for soft-tissue pathology 14
Compression from soft tissue masses may be missed on CT without contrast injection 15
CT has 94-100% sensitivity for thoracolumbar spine fractures, but cannot adequately visualize the spinal cord itself 14
Radiographs are inadequate for evaluating spinal cord compression, with only 49-62% sensitivity for thoracic spine fractures and 67-82% for lumbar fractures 14

Imaging Considerations

Always image the entire spine when cord compression is suspected, as 20% of spine injuries have a second noncontiguous spinal injury 14

MRI Imaging Guidelines for Suspected Cervical and Thoracic Spinal Cord Compression with Autonomic Instability

Imaging Recommendations

The American College of Radiology recommends obtaining non‑contrast MRI of both the cervical and thoracic spine as the initial imaging studies in patients with suspected multilevel spinal cord compression and autonomic instability. [16][17]

Cervical Spine MRI Protocol

Non‑contrast MRI of the cervical spine is the gold‑standard modality for detecting soft‑tissue injuries such as disc herniation, epidural hematoma, ligamentous disruption, and spinal cord compression that are not adequately visualized on CT. 16
The cervical protocol should include high‑resolution T1‑weighted and T2‑weighted sequences in both sagittal and axial planes to assess the spinal cord, nerve roots, disc material, and sites of compression. 18

Thoracic Spine MRI Protocol

Non‑contrast MRI of the thoracic spine is essential when thoracic cord involvement is suspected, because thoracic myelopathy from compression constitutes a surgical emergency. 17
The thoracic protocol should mirror the cervical approach, employing T1‑weighted and T2‑weighted sagittal and axial sequences to identify disc herniation, hematoma, or ligamentous injury. 17

Rationale for Non‑Contrast Imaging

Intravenous contrast is not required initially unless there is clinical suspicion for infection, neoplasm, or inflammatory disease; these entities are not typical in acute traumatic settings. 17

Clinical Correlates Supporting Multilevel Imaging

Worsening hand symptoms with elbow flexion and arm elevation suggest cervical nerve‑root compression (or thoracic outlet syndrome) and therefore mandate cervical spine evaluation. [18][16]
Progressive foot and lateral thigh numbness point to thoracic cord involvement, reinforcing the need for thoracic imaging. 17
Autonomic instability (blood pressure fluctuations, syncope, sweating) can result from cervical or high‑thoracic cord compression affecting sympathetic pathways, making multilevel imaging mandatory. 17

Critical Pitfalls to Avoid

CT alone should not be relied upon; while excellent for bony fractures, CT is markedly inferior to MRI for detecting soft‑tissue pathologies that cause neurologic deficits and may require surgical intervention. 16
Imaging should not be delayed; progressive myelopathy with autonomic instability may necessitate urgent surgical decompression. 17
Routine use of contrast‑enhanced MRI at the initial stage is discouraged unless the non‑contrast study is nondiagnostic or raises suspicion for infection, tumor, or inflammatory disease. 17

When to Add Contrast or Use Alternative Imaging

Intravenous contrast should be added only if the initial non‑contrast MRI suggests infection (e.g., epidural abscess), tumor, or inflammatory myelitis. 17
CT myelography is appropriate when MRI is contraindicated (e.g., implanted cardiac device, severe claustrophobia) or when detailed bony anatomy is required for surgical planning. [16][17]
Non‑contrast CT may be employed for pre‑operative osseous assessment but must not replace MRI for the initial diagnostic work‑up. 17

Autonomic Instability Considerations

Blood pressure swings, sweating, and syncope raise concern for high cervical or thoracic cord compression affecting autonomic pathways; this scenario constitutes a neurosurgical emergency that requires immediate imaging. 17
Autonomic dysreflexia can occur with cord lesions above the T6 level, presenting with blood pressure instability and sweating; prompt spinal imaging is warranted. 17

Imaging Guidelines for Traumatic Intervertebral Disc Injury

Initial Imaging Strategy

CT of the cervical, thoracic, and lumbar spine without IV contrast should be the first imaging study for all blunt‑trauma patients who meet NEXUS or Canadian C‑Spine Rule criteria, because it provides the highest sensitivity for fractures, subluxation, and bony instability. – American College of Radiology 19
After CT, an MRI of the entire spine without IV contrast must be obtained promptly to identify soft‑tissue injuries (disc herniation, epidural hematoma, cord contusion, ligamentous disruption) that CT cannot detect and that often require surgical intervention. – American College of Radiology [19][20]21

Indications for Urgent MRI

Any patient with a neurologic deficit (motor weakness, sensory loss, bowel/bladder dysfunction) warrants immediate MRI regardless of CT findings. – American College of Radiology [19][20][22][21]
If clinical suspicion exists for spinal cord or nerve‑root injury even when CT is normal, MRI should be performed without delay. – American College of Radiology [19][20]21
Obtunded patients who cannot be clinically cleared must receive MRI because they cannot report neurologic symptoms. – American College of Radiology [19][20]
MRI is indicated when imaging or physical findings suggest ligamentous injury (e.g., widened interspinous distance, facet dislocation, abnormal alignment). – American College of Radiology [19][20]
Mechanically unstable spine injuries identified on CT or plain radiographs require MRI to complement CT for surgical planning. – American College of Radiology [19][22]

Key MRI Findings and Their Clinical Impact

Traumatic disc herniation compressing the spinal cord or nerve roots occurs in roughly one‑third of cervical spinal‑cord‑injury patients. – Anaesthesia 23
Epidural hematoma is present in about 9 % of cervical spine trauma cases; more than 13 % of these hematomas are missed on CT and are only detected by MRI. – Anaesthesia 23
Severity of cord compression, extent of intramedullary hemorrhage, and length of cord edema on MRI are strong predictors of neurologic outcome. – American College of Radiology [19][20][22][21]
Disruption of the discoligamentous complex is invariably seen in mechanically unstable cervical spine injuries. – American College of Radiology 22

Recommended MRI Protocol

T2‑weighted sequences (sagittal and axial) are essential for visualizing disc herniation, cord edema, and ligamentous injury. – American College of Radiology [19][20]
Gradient‑echo sequences should be added to improve detection of hemorrhage and epidural hematoma. – American College of Radiology [19][20]
IV contrast is not required for acute traumatic disc injury unless there is suspicion of infection, tumor, or inflammatory disease. – American College of Radiology 21

Timing of MRI and Surgical Intervention

When MRI can be obtained without delaying definitive surgery or compromising patient safety, it should be performed to guide operative planning. – Anaesthesia 23
MRI‑guided surgical protocols have demonstrated superior functional recovery (≈12 % vs 0 % regaining ambulation in patients with complete motor deficits) and shorter intensive‑care stays compared with protocols that omit MRI. – Anaesthesia 23
Emergency decompressive surgery should be performed within 24 hours of neurologic deficit onset to maximize long‑term neurologic recovery. – Anaesthesia 23

Alternative Imaging When MRI Is Contraindicated

CT myelography is the second‑line imaging modality for patients who cannot undergo MRI (e.g., pacemaker, severe claustrophobia) or when MRI is unavailable. – American College of Radiology [22][21]
CT myelography can evaluate spinal canal narrowing caused by disc herniation or epidural hematoma, but it is less sensitive than MRI for detecting cord contusion, intramedullary hemorrhage, and post‑ganglionic nerve‑root injury. – American College of Radiology 22

Common Pitfalls to Avoid

Do not rely on CT alone in patients with neurologic deficits; CT misses most soft‑tissue pathologies that influence surgical decision‑making. – American College of Radiology 21
Do not forgo MRI in obtunded patients with a normal CT, as they may harbor significant ligamentous or disc injuries that are clinically silent. – American College of Radiology [19][20]
Avoid assuming isolated thoracolumbar ligamentous injury without fracture; when CT is normal and the patient is neurologically intact, additional MRI screening is not indicated. – American College of Radiology [19][20]