Sandbox spinalcord

Causes

Common causes of acute spinal cord compression include

• Trauma is a leading cause of acute spinal cord compression
• Primary or secondary metastatic spinal tumor
• Vertebral compression fractures due to osteomalacia, osteoporosis, corticosteroid therapy
• Intervertebral disk herniation
• Epidural abscess
• Epidural hematoma

Risk factors

Common risk factors in the development of spinal cord compression include

• Cervical spondylosis
• Atlantoaxial instability
• Congenital conditions (tethered cord)
• Osteoporosis
• Ankylosing spondylitis
• Rheumatoid arthritis of the cervical spine

Less common risk factors

• IV drug abuse
• Immunocompromised

Pathophysiology

Anatomy

• The spinal cord extends from the foramen magnum down to the level of the first and second lumbar vertebrae.
• At L2 level spinal cord transforms into spinal roots and forms a cone-shaped structure called conus medullaris.
• The cord is protected by the vertebral column, which is mobile and allows for movement of the spine.
• It is enclosed by the dura mater and the vessels supplying it.
• The cord floats in the cerebrospinal fluid which acts as a buffer to movement and early degrees of compression.
• The cord substance contains a gray area centrally and is surrounded by white matter communication tracts, both ascending and descending.

Pathogenisis

• The spinal cord and nerve roots depend on a constant blood supply to perform axonal signaling.
• Conditions that interfere, either directly or indirectly, with the blood supply will cause malfunction of the transmission pathway.
• Injury to the spinal cord or nerve roots arises from stretching or from pressure.
• It initiates a cascade of events in the gray matter and white matter, and results in hypoperfusion and eventually hemorrhagic necrosis.
• The extent of necrosis depends on the severity of the trauma, concomitant compression, perfusion pressures and blood flow, and administration of pharmacological agents.
• The tissue responses by gliosis, demyelination, and axonal loss.
• This results in injury to the white matter (myelinated tracts) and the gray matter (cell bodies) in the cord with loss of sensory reflexes (pinprick, joint position sense, vibration, hot/cold, pressure) and motor function.
• Rapid compression will result in the collapse of the venous system, resulting in vasogenic edema.
• Vasogenic edema exacerbates parenchymal pressure and may lead to rapid progression of dysfunction.

Dissemination

Hematogenous spread

Associated conditions

Lesions may develop gradually or acutely and be complete or incomplete. Incomplete lesions often present as distinct syndromes  as follows:

	Sensory dysfunction	Motor dysfunction	Sphincter dysfunction
Central cord syndrome	Sensory loss is very rare	Upper extremity weakness distal muscles are involved more than proximal
Brown-Séquard syndrome	Ipsilateral position and vibration sense loss Contralateral pain and temperature sensation loss	Motor loss ipsilateral to cord lesion
Anterior cord syndrome	Loss of pin and touch sensation Vibration, position sense preserved	Motor loss or weakness below the level of compression
Transverse cord syndrome	Loss of sensation below level of compression	Loss of voluntary motor function below the level of compression	Sphincter control lost
Conus medullaris syndrome	Saddle anesthesia Sensory loss may range from patchy to complete transverse pattern	Weakness may be of upper motor neuron type	Sphincter control impaired
Cauda equina syndrome

Epidemiology and Demographics

Epidemiology

Incidence

• The annual incidence of spinal cord compression is estimated to be about 11,000 new cases/yr in the United States
• The worldwide incidence of spinal cord compression varies from 8 to 246 cases per million inhabitants per year.

Prevelance

• The global prevalence of spinal cord injury (SCI) has been reported to vary from 236 to 1,298 per million inhabitants.
• In United States the prevalence is estimated to be 171,000 persons.

Demographics

Gender

Spinal cord compression is more commonly seen in males than females

Age

It is more common in 40's

Race

No racial predilection

Symptoms

Symptoms of spinal cord compression depends on the anatomic level involved in compression and can be discussed as follows

Type of spinal involvement	Symptoms
Cervical	Headache Neck, shoulder or arm pain Loss of sensation over the upper extremities Motor weakness of neck, shoulder and arm
Thoracic	Pain in the chest and/or back Loss of sensation below the level of the compression Increased sensation above the level of the compression Muscle weakness Paralysis Positive Babinski reflex Bladder and bowel problems Sexual dysfunction
Lumbosacral	Low back pain that may radiate down the legs and/or perineal area Weakness in the legs and feet Loss of sensation in the legs and feet Bladder and bowel problems Sexual dysfunction Foot drop Decreased or absent reflexes in the legs

Laboratory findings

Spinal cord compression is diagnosed based on clinical history and imaging studies. Other lab studies like CBC, CSF, clotting studies and electrolyte exam helpful in excluding infection as a cause.

• CBC shows increased neutrophil count in cases of infection.
• ESR and CRP are elevated
• Blood and CSF cultures are positive in case of an epidural abscess or osteomyelitis.
• Tumor biopsy positive for malignant cells if compression of spinal cord is due to malignancy
• Urodynamic studies reveal reduced bladder contractility and sphincter dysfunction.

X-ray spine

• Patients with acute spinal cord injury should be immobilized with a cervical collar and backboard/head strap while imaging.
• Plain radiographs are useful in assessing mechanical stability of the spine in trauma cases.
• Multidetector CT with sagittal and coronal reconstructions is supplanting the role of plain radiographs, especially in the setting of multiple trauma.
• Plain x-ray film is indicated in all patients presenting with chronic back pain as a initial symptom, if nondiagnostic MRI is ordered.

CT Spine

• MRI and CT imaging are preferred diagnostic modalities in confirming the diagnosis
• CT spine is preferred for detection of spinal canal abnormalities.
• Anteroposterior, lateral, views are required to show alignment of bone structures.

MRI Spine

• MRI is the study of choice when there is incomplete paralysis or under other circumstances where direct visualization of neural or ligamentous structures is clinically necessary.
• MRI is the best imaging method for evaluation of neural tissue.
• MRI has largely replaced CT scanning in the noninvasive evaluation of patients with painful myelopathy because of its superior soft-tissue resolution and multiplanar capability.
• Urgent MRI is recommended for all patients who have new-onset urinary symptoms with associated back pain or sciatica.
• Patients who present with a tumor history should undergo CT- or MRI-enhanced imaging.
• Plain radiographs of the entire spine should then be performed, followed by CT or MRI with and without contrast enhancement.
• CT-guided biopsy of suspected tumors can confirm the diagnosis.
• Epidural abscess is best detected by MRI.
• CT guidance may also allow for surgical aspiration and diagnosis of infection or drainage of an epidural abscess.