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.

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.

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.