Cervical Spine Abnormalities

Introduction

Embryology

  • Vertebrae develop from sclerotomes, derived from somites and from the notochord.
  • The dermatomyotome forms spinal musculature and skin.
  • Organogenesis occurs concurrently with spine development, leading to multisystem abnormalities.
Structure Ossification Centers
Atlas 3 (lateral masses and body)
Axis 5 primary (H shape on X-ray) and 2 secondary
Dens Appears at age 3 and fuses at age 12
Dentocentral Synchondrosis Fuses by age 7

Atlanto-Occipital Stability

  • Stability provided by facet congruity, capsular ligaments, and the tectorial membrane, extending from the posterior longitudinal ligament to the foramen magnum.

Atlanto-Axial Stability

  • Static Stability: Odontoid peg and transverse ligament.
  • Secondary Stabilisers: Alar ligaments and apical ligament.

Atlantoaxial Instability

  • AP or rotatory instability due to conditions such as Down’s syndrome, Morquio’s syndrome (hypoplastic odontoid), or Grisel’s Disease.
  • Imaging: Atlantoaxial AP instability if ADI >5 mm; Powers ratio <1; SAC ≥13 mm (similar to PADI); Rule of 3rds at the odontoid level.

Basilar Invagination

  • Defined by proximal migration of the odontoid through the foramen magnum.
  • Common in Klippel-Feil syndrome, Morquio, Down syndrome, achondroplasia.
  • Imaging: Present if PEG is above McRae’s line or >5 mm above McGregor’s line.
  • Management: Surgical intervention to prevent or stabilize neurologic symptoms.

Klippel-Feil Syndrome

  • Failure of cervical spine segmentation.
  • Classic Features (in <50%): Stiff neck, low hairline, webbed neck.
  • Associations: Congenital scoliosis, Sprengel’s shoulder, renal and cardiac anomalies.
  • Management: Supportive; myelopathy may require decompression and stabilization.

Os Odontoidum

  • Occurs when odontoid ossification centers fail to coalesce by 12 years, appearing similar to a type-2 peg fracture.
  • Symptoms: Neurologic issues with ADI >4 mm; SAC <13 mm.
  • Treatment: C1-3 fusion.

Intervertebral Disc Calcification

  • Self-limiting condition with calcified C-spine discs, low-grade fever, neck pain, increased ESR, and decreased ROM.

Down’s Syndrome

  • Trisomy 21, commonly associated with atlantoaxial and atlanto-occipital instability.
  • Most children are asymptomatic; treat symptomatically or if severe instability is present.

Morquio’s Syndrome

  • Mucopolysaccharidosis with 100% incidence of atlantoaxial instability due to odontoid hypoplasia.
  • Low threshold for stabilization due to high incidence of cord injury.

Torticollis

  • Defined by head tilt with chin rotation.
  • Causes:
    • Acute torticollis (self-limiting).
    • Congenital anomalies (from birth, painless).
    • Ocular, neurogenic, psychologic, and muscular torticollis.
  • Management: Physiotherapy for young children; surgical release for older children if necessary.
Cause of Torticollis Description Management
Acute Torticollis No SCM contracture, muscle spasm Self-limiting
Congenital Anomalies Webbed neck, low hairline No treatment needed
Muscular Torticollis SCM contracture Physiotherapy, SCM release if needed

Larsen’s Syndrome

  • Characterized by congenital dislocations (e.g., radial head, knees, hips) and rapidly progressive kyphosis of the cervical spine.
  • Management: Responds well to cervical spine PIS.
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