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ICD-9-CM Codes

  • 738.4 Acquired spondylolisthesis

  • 756.12 Spondylolisthesis congenital

  • 805.01 Closed fracture of first cervical vertebra

ICD-10-CM Codes

  • M43.10 Spondylolisthesis, site unspecified

  • Q76.2 Congenital spondylolisthesis

  • S12.000A Unspecified displaced fracture of first cervical vertebra, initial encounter for closed fracture

  • S12.001A Unspecified nondisplaced fracture of first cervical vertebra, initial encounter for closed fracture

Preferred Practice Pattern

Key Features


  • Anterior (forward) translation of a vertebra

  • Fracture of the anterior and posterior arches of C1 vertebra

  • Slipping of the vertebra in relationship to the vertebra below

  • Ataxia

  • Fracture widens at the pars

Essentials of Diagnosis

  • Diagnosis made by x-ray

  • Clinical examination may find step deformity

  • Axial load on top of the head

  • Reports diving into a shallow pool

General Considerations

  • Instability

  • Avoid extension positions that increase symptoms


  • Usually from landing on head, as with diving into a shallow pool

Clinical Findings

Signs and Symptoms

  • Ataxia

  • Injury to vertebral artery

  • Cervical, shoulder, arm, upper-extremity pain; often radiating into lower extremities if central cord involved

  • Constricted pupil (Horner's sign)

  • Stiffness along spine

  • Headaches

  • Pain in cervical spine worsens with extension

Functional Implications

  • Difficulty maintaining standing postures secondary to neck pain

  • Difficulty with movements (reaching overhead) secondary to pain

  • Limited sports participation

  • Can cause quadriplegia or death

Possible Contributing Causes

  • Forceful extension from hit under the chin (as in sports)

  • Car accident, hit from rear

  • Hyperextension of the cervical spine

  • Diving into a shallow pool

Differential Diagnosis

  • Peripheral nerve impairment

  • Spinal tumor

  • Peripheral neuropathy

  • Paraspinal spasms

  • Degenerative disk disease

  • Hangman's fracture

    • C2 vertebra anterior translated on C3 with fracture of C2 pedicles

Means of Confirmation or Diagnosis


  • MRI helps to visualize compressed or inflamed nerve root in diagnosis

  • X-ray/plain-film radiograph to see vertebra position

  • CT to show herniation compressing the spinal canal/nerves

  • Electrodiagnostic/nerve conduction testing can help to determine a specific impaired nerve function

Findings and Interpretation

  • Fracture of the anterior and posterior arches of C1 vertebra


  • To hospital for imaging

  • To surgeon for surgical consult if myelopathy suspected

    • Fusion

  • To physician for anti-inflammatory medication

  • To orthopedist for halo vest traction device, cervical bracing


  • Restricted mobility of the upper cervical spine

  • Hypermobility

  • Noted weakness of neck musculature


  • Rest

  • Bracing

  • Address pain

    • Electrical stimulation


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