Spinal Cord Injury Facts

• Spinal cord injury results in loss of functional mobility or feeling, due to damage to the spinal cord and associated nerves.
• Trauma (falls, accidents, medical conditions) can cause it.

Incidence of Spinal Cord Injuries

• Approximately 20,800 Australians were living with a spinal cord injury (SCI) at the time of publication.

• Spinal cord injuries cost the Australian economy $74.5 billion in personal and health care, lost productivity and reduced well-being of the 20,800 Australians; approximately $3.7 billion per year.

• The World Health Organization (WHO) records approximately 350,000 new SCI patients each year.

• Traumatic causes account for 81% of SCIs in people under 65, including falls, road accidents, and sports injuries.

• In those over 65, non-traumatic causes, such as tumors and degenerative disorders, are the leading cause.

• The spinal cord need not be severed for loss of function.

• A person can break their back or neck without sustaining spinal cord injury.

• Paraplegia is the impairment in motor or sensory function of the lower extremities.

• Tetraplegia/ Quadriplegia is paralysis caused by illness/injury that results in partial or total loss of all four limbs and torso.

Pathophysiology of Spinal Cord Injury

• Edema, haemorrhage, ischemia, inflammatory cell infiltration, and cell death occur within 0-48 hours.
• Necrosis and/or apoptosis of neurons and glial cells also occur within 0-48 hours.
• Persistent inflammatory cell infiltration causes additional cell death after 2-4 days post injury.
• Cystic microcavities form, and the extracellular architecture of the cord sustain damage after 2-4 days post injury.
• Axons degenerate, and the astroglia scar matures to become a potent inhibitor of regeneration within 2 weeks to 6 months.
• Traumatic SCI is divided into Primary and Secondary injuries.
• The stages are temporally divided into acute (<48 hours), subacute (48 hours to 14 days), intermediate (14 days to 6 months), and chronic (>6 months) phases
• The initial traumatic event (primary injury) produces immediate mechanical disruption and dislocation of the vertebral column.
• This leads to compression or transection of the spinal cord.

Diagnosing Spinal Cord Injury

• Plain X-ray, CT and MRI are the most used radiological tools for investigating damage to the spine and SCI.
• X-rays are useful to detect gross fracture dislocation injuries often associated with SCI.
• CT has largely supplanted X-ray for the diagnosis of bone injuries in patients with trauma.
• MRI can identify spinal cord transection and can evaluate for the presence of edema and/or haemorrhage.

Classifying Spinal Cord Injury

• Grade 1: No sensory or motor function below the neurological level.
• Grade 2: Sensory but not motor function is preserved below the neurological level of injury.
• Grade 3: Motor function below neurological level of injury is preserved with more than half of muscle having some limited movement.
• Grade 4: Motor function below neurological level of injury is preserved with less than half of muscle having some limited movement.

Vertebral Column

• The central axis of the human body consists of 33 vertebrae.
• Seven cervical vertebrae, including atlas (C1) and axis (C2).
• The atlas (C1) holds the head on the neck
• Axis (C2) is the point of articulation where the head turns on the neck (axis of rotation).
• Twelve thoracic vertebrae, each articulates with a pair of ribs.
• Five lumbar vertebrae, large vertebrae that support body weight.
• Five fused vertebrae offer stability in weight transfer.
• Four vertebrae, variable but fused.
• The column is concave posteriorly, bringing the center of gravity into a vertical line.
• The vertebral column is concave anteriorly, reflecting the original shape of the embryo.

Vertebrae Anatomy

• The Vertebral Body is the weight-bearing portion of a vertebra and increase in size down the spine.
• The Vertebral Foramen contains the spinal cord and its meningeal coverings.
• The Arch is the site used for articulation with adjacent vertebra and attachment point for ligaments and muscles.
• The Lamina connect transverse processes to the spinous process.
• Transverse processes: lateral extensions from the union of the pedicle and lamina
• The Pedicle attaches transverse processes to the body.
• The Spinous process is a projection that extends posteriorly from the union of two laminae.
• The Intervertebral foramen: area traversed by spinal nerve roots and associated vessels.

Joints and Ligaments of Vertebral Arches and Bodies

• Intervertebral joints occur between adjacent vertebral bodies.
• They are stable and weight-bearing joints.
• Intervertebral discs have a nucleus pulposus “shock absorber:" compressing when load bearing
• Its anulus fibrosus resists compression and shearing forces

Cervical Vertebrae:

• Atlas (C1) are ringlike bones; the superior facet articulates with the occipital bone.
  • They have two lateral masses with facets.
  • Have no body or spinous process.
  • C1 rotates on articular facets of C2, vertebal artery runs in groove on posterior arch.
• Axis (C2): Dens projects superiorly.
  • Axis are the strongest cervical vertebra.
• C3 to C7 have large, triangular vertebral foramen and a transverse foramen through which vertebral artery passes (except C7).
• The narrow intervertebral foramina puts nerve roots at risk of compression.
• C3 to C5 have short, bifid spinous process.
• C6 to C7 have long spinous process.
• C7 is vertebra prominens.

Thoracic and Lumbar Vertebrae

• The thoracic spine has 12 pairs of ribs articulate with the thoracic vertebrae making it more rigid in inflexible.
• The lumbar spine is comparatively large for bearing the weight of the trunk and are fairly mobile.
• Thoracic (T1-T12) have Heart-shaped body, with facets for rib articulation and a Small circular vertebral foramen.
  • They also have Long transverse processes, with facets for rib articulation in T1-T10.
  • Their Long spinous processes slope posteriorly and overlap the next vertebra.
• Lumbar (L1-L5 have kidney-shaped body, massive for support and midsized triangular vertebral foramen.
  • Their facets face medial or lateral direction, which permits good flexion and extension.
  • Their spinous process is short, strong, and horizontal, (L5) has largest vertebra with massive transverse processes.

Sacrum and Coccyx

• The Sacrum: five fused vertebrae provides support for the pelvis.
• The Coccyx usually consists of four vertebrae that lacks vertebral arches and have no vertebral canal. -Sacrum (S1-S5) has Large, wedge-shaped bone that transmits body weight to pelvis and has five fused vertebrae, with fusion complete by puberty. They have Four pairs of sacral foramina on dorsal and ventral(pelvic) side. -Has sacral hiatus, the opening of sacral vertebral foramen.
• Coccyx (Co1-Co4) Often the Col often is not fused.
  • Co2 to Co4 are fused, they have no pedicles, laminae, or spines. It is a Remnant of our embryonic tail.

Spinal Cord Relationship to other regions

• Cervical region: muscular framework of neck which supports and moves the head.

• Thoracic region: skeletal framework of the thorax, abdomen, and pelvis that provide attachments for muscles and fascia.

• Lower limbs are firmly anchored to the vertebral column through articulation of the pelvic bones with the sacrum.

• Spinal cord is surrounded by a series of three connective tissue membranes (the meninges).

Anatomy of the Spinal Cord

• The spinal cord organized into grey (neuronal cell bodies) and white matter (myelinated axons).

• White matter can be further subdivided into several ascending or descending tracts which transmit specific information, such as sensory (e.g.: temperature or itch) or motor information.

• Spinal nerve roots enter the spinal cord and either convey sensory information to the spinal cord or convey motor information to the periphery (through the motor or ventral root.

• Spinal nerves originate from spinal cord at increasingly oblique angles from vertebrae Cl.

• Nerve roots pass in vertebral canal for increasingly longer distances.

• Spinal cord typically ends between vertebrae LI and LII.

• Direct continuation of medulla oblongata.

• Enlarged diameter in the cervical and lumbar regions.

• Conus medullaris located between L1-L2 and has a Cauda equina

• The spinal nerve exits vertebral canal laterally through an intervertebral foramen.

• 31 pairs of spinal nerves: 8 cervical; 12 thoracic; 5 lumbar; 5 sacral pairs; 1 coccygeal pair.

• Afferent sensory axons come from skin, skeletal muscle, and joints or viscera.

• Autonomic axons go to smooth muscle, cardiac muscle, and glands.

• Somatic efferent (motor) axons go to skeletal muscle.

Spinal Cord Injury Symptoms

• Numbness, tingling, or changes in sensation in hands and feet.
• Paralysis (loss of movement).
• Pain or pressure in the head, neck, or back.
• Weakness in any part of the body.
• Unnatural positions of the spine or head.
• Loss of bladder and bowel control.
• Problems with walking.
• Difficulty breathing.
• Changes in sexual function.
• Depend on where SCI has occurred

Spinal Cord Injury

• Injuries in the cervical and high thoracic cord can disrupt the sympathetic outflow to the heart and vasculature. The parasympathetic output, however, is persevered.

• Parasympathetic innervation to the heart dominates in cervical and upper thoracic injuries.

• This leads to Bradycardia and decreased cardiac output.

• Furthermore, decreased sympathetic outflow to reduce tone in vasculature promoting blood pooling and reducing venous return to the heart.

• It can also decrease muscle tone resulting in decreased venous return.

• These factors can lead to hypotensive symptoms, particularly with exertion or upright positioning, such as headaches and sweating.

• Above C4 may require a ventilator to breathe due to loss of involuntary functions.

• C5: shoulder and biceps under control, but no control at the wrist or hand

• C6: control of the wrist but not the hand

• C7 and T1: can straighten arms but have only limited hand and finger dexterity.

• T1 to T8: control of hands but lack of abdominal muscle control leaves poor trunk control

Thoracic Spinal Cord Injury Prognosis and Recovery

• Body type, existing medical conditions and other injuries can affect achieving independence.
• Patients with a thoracic spinal cord injury may:
  • have normal arm, hand and upper-body movement
  • use a manual wheelchair
  • learn to drive a modified car
  • stand in a standing frame or walk with braces
• Reduce inflammation of the injured cord by using Intensive exercise programs such as NeuroMoves Locomotor Training and Activity Based Therapy assists in improvement of independent functional abilities