AANS2000Outline of

Neurosurgery

E. R. Flotte, 2008

 

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Spine

 

 

Cervical Pathology

Thoracic Pathology

Lumbar Pathology

Spinal Tumors

Spinal Procedures

 

 

Spine Trauma

Spinal Infections

Spinal Dysraphisms

 

 

Spinal Anatomy

 

Neuroanatomy: Spinal Anatomy

 

Lines

·         McRae: foramen mangum diameter, >35mm, any protrusion of odontoid above is abnormal; Chamberlain: palate to foramen magnum, odontoid not >1/3 or 6mm above;

·         Wackenheim: posterior axial line – basion (tip of clivus tip) should be anterior to it

·         McGregor: palate to occiput, basion should not be >4.5mm above;

·         Fishgolds digastric line: basion should be above it

·         Basion-Dens interval: <12mm. Basion-Atlanto interval: <12mm.

·         Atlantodental interval (ADI): abnormal >3mm adults, >4mm kids. >4mm = transverse ligament disruption possible, >6mm likely.

·         Prevertebral shadow: <7mm at C2, <22mm at C6 (kids 14mm)

·         Platybasia: clival angle >145°.

·         Basilar Invagination: Odontoid process penetrates foramen magnum

·         Basilar Impression: “Infolding of the skull base” (Menenzes JN 9/06)

 

Landmarks: hyoid (C3), thyroid cartilage and bifurcation of the common carotid artery (C4), cricoid cartilage (C6)

Conus lesion: Vs cauda equina: less pain, symmetric, early autonomic signs

 

 

Spinal Stability

·         General criteria for instability:

  1. >50% vertebral body collapse
  2. >20° sagittal kyphosis
  3. >10° coronal angulation
  4. >5mm vertebral translation
  5. Neurologic instability: risk to neural elements
  6. Mechanical instability: risk of painful or progressive deformity

·         Denis’ Three-Column Model: Divided by mid-vertebral body line and PLL.  Designed for thoracolumbar fractures.

·         Kostuik and Errico: 6 columns - Denis’ 3 columns divided into left and right halves. Unstable if ≥ 3 columns affected. Designed for neoplasms.

·         White-Punjabi guidelines for cervical instability: ≥ 4mm subluxation, ≥ 11o angulation (inferior endplates).

o        Don’t get flexion/extension X-rays. If <4mm subluxation get flexion/extension.

·         Clinical definition: No excessive displacement or deformity or neurologic compression under physiologic loads

 

Degenerative Spine Disease

·         Includes:

o        Disc dehydration, collapse, herniation, annular tears

o        Facet disease, hypertrophy

o        Osteophytes

o        Spondylolisthesis

o        Ligamentous hypertrophy

o        Vertebral body endplate damage and edema (Modic changes on MRI), Schmorl’s nodes, loss of height

·         Causes: Spine mechanics, activity, smoking, body weight

·         May cause axial spine pain, disc herniation, spinal stenosis

Cervical Spine

 

Congenital Abnormalities

·         Imaging: Xrays (plain and dynamic), CT (3D), MRI (dynamic), angiography (MR/CT)

·         See JN:S 9/04

 

Os Odontoideum

·         Odontoid ossification centers: 2 primary at base, 1 secondary at tip.