Spine Imaging: Trauma and Degenerative Disease

Spine Anatomy & Modalities - Bones, Cords, & Scans

• Vertebral Column:
  • Bones: Cervical (7), Thoracic (12), Lumbar (5), Sacrum, Coccyx. Vertebral body, pedicles, laminae, spinous/transverse processes.
  • Intervertebral Discs: Annulus fibrosus, nucleus pulposus.
  • Ligaments: ALL, PLL, ligamentum flavum.
• Spinal Cord & Nerves:
  • Cord: Grey matter (H-shape), white matter (tracts).
  • Nerve roots: Exit via neural foramina.
• Imaging Modalities:
  • X-ray: Initial assessment; alignment, gross fractures, degenerative changes.
  • CT: Superior for bone detail (complex fractures, osseous stenosis). CT Myelography if MRI contraindicated.
  • MRI: Modality of choice for cord, discs, soft tissues.
    • T1WI: Anatomy, marrow.
    • T2WI/STIR: CSF bright; disc pathology, cord edema/myelomalacia, ligament injury.
    • Post-contrast: Infection, tumor, inflammation.

⭐ Best MRI sequence for cord edema/myelomalacia: T2WI/STIR.

Spinal Trauma Imaging - Cracks, Snaps, & Wobbles

• Initial Imaging: X-ray (AP/Lat, Odontoid). CT is gold standard for bony detail. MRI for suspected cord, ligament, or disc injury.
• Stability Assessment:
  • Denis 3-column theory (📌 AMP: Anterior, Middle, Posterior). Instability if ≥2 columns involved.
  • TLICS Score: Assesses Injury Morphology, Neurological Status, PLC Integrity. Score >4 often indicates surgery.
• Key Fracture Patterns:
  • Cervical: Jefferson (C1 burst), Hangman's (C2 pedicles), Odontoid (Type II most unstable), Flexion Teardrop (highly unstable).
  • Thoracolumbar: Compression (anterior column), Burst (anterior + middle, >50% canal compromise critical), Chance (flexion-distraction).
• TLICS Score Components & Decision:

⭐ Jefferson Burst Fracture: C1 atlas fracture (axial load); bilateral anterior/posterior arch #. Lateral C1 mass displacement on odontoid view.

Disc Degeneration & Herniation - Discs Under Pressure

• Disc Degeneration (Spondylosis):
  • Patho: ↓ Proteoglycans, ↓ NP water → ↓ disc height, annular tears, vacuum sign, osteophytes.
  • MRI: NP shows ↓ signal on T2W ("black disc").
  • Endplate (Modic) Changes: 📌 123-WEF:
    • Type 1: Water (edema) - ↓T1, ↑T2.
    • Type 2: End-stage (fatty) - ↑T1, ↑/iso T2.
    • Type 3: Fibrosis (sclerosis) - ↓T1, ↓T2.
• Disc Herniation: Displacement of disc material.
  • Types:

    Type	Description	Annulus Status
    Bulge	Circumferential, symmetric extension	Intact
    Protrusion	Focal/broad; base > dome	Intact
    Extrusion	Focal; dome > base OR material through annulus	Disrupted
    Sequestration	Extruded fragment, no disc continuity	Disrupted

  • Locations: Central, paracentral (lateral recess), foraminal, extraforaminal (far lateral).

⭐ Most common sites for lumbar disc herniation are L5-S1 and L4-L5.

Spondylosis & Spondylolisthesis - Slipping & Spurring

• Spondylosis: Chronic spine degeneration (cervical/lumbar).
  • Features: Osteophytes (bony spurs), ↓ disc height, vacuum phenomenon, facet joint hypertrophy.
  • Causes: Foraminal/central canal stenosis.
• Spondylolisthesis: Anterior vertebral displacement over vertebra below.

  • Meyerding Grading (slip severity):

    • Grade I: 0-25%
    • Grade II: 26-50%
    • Grade III: 51-75%
    • Grade IV: 76-100%
    • Grade V (Spondyloptosis): >100%

  • Spondylolysis: Pars interarticularis defect (fracture/elongation). Common L5. Precursor to isthmic type.

    ⭐ Imaging: "Scottie dog" with collar (pars defect) on oblique lumbar X-rays.

  • 📌 Wiltse Classification (Etiology): Dysplastic, Isthmic, Degenerative, Traumatic, Pathologic, Iatrogenic. Mnemonic: "Do I Die To Pass Internships?"

High‑Yield Points - ⚡ Biggest Takeaways

• Jefferson fracture (C1 burst) & Hangman's fracture (C2 pedicles) are key unstable cervical injuries.
• MRI is crucial for spinal cord injury, ligamentous tears, and disc herniation assessment.
• CT is first-line for acute bony trauma, offering precise fracture classification (e.g., Denis, AO).
• Degenerative Disc Disease (DDD) on MRI: disc desiccation (↓T2 signal), osteophytes, Modic changes.
• Spinal stenosis (central/foraminal narrowing) is best seen on MRI axial T2WI.
• Spondylolisthesis (vertebral slip) is graded by Meyerding; look for spondylolysis (pars defect).