Standard clinical features associated with atlantoaxial instability (AAI) include cervical pain, neurological deficits, and signs of spinal cord involvement. Patients often present with neck pain and stiffness due to abnormal movement or subluxation at the atlantoaxial joint, which can lead to mechanical irritation Giussani et al. 2018Ferrante et al. 2019. Neurological manifestations range from unsteady gait and frequent falls to more severe progressive myelopathy including limb weakness, hyperactive deep tendon reflexes, and sensory changes caused by spinal cord compression at the craniovertebral junction Giussani et al. 2018Wang et al. 2024.
In some cases, especially with associated bony anomalies like os odontoideum, patients may also present with symptoms related to vertebral artery compression such as dizziness, cerebellar ataxia, or even posterior circulation ischemic strokes due to vascular insufficiency Wang et al. 2024. Clinical examination may reveal upper motor neuron signs such as spasticity and pathological reflexes without overt cranial nerve involvement in many cases Giussani et al. 2018Wang et al. 2024.
Furthermore, in inflammatory conditions like rheumatoid arthritis or mucopolysaccharidoses, AAI can manifest early with neck pain followed by neurological impairment due to atlantoaxial subluxation Ferrante et al. 2019Giussani et al. 2018. Rarely, acute trauma or minor mechanical insults can precipitate sudden tetraplegia in unstable joints Giussani et al. 2018.
Dynamic symptoms related to neck movement (flexion-extension), including worsening neurological signs or transient ischemic symptoms attributable to vertebral artery compromise, may also be present and are best evaluated by imaging Giussani et al. 2018Wang et al. 2024. Overall, AAI classically presents with a combination of neck pain, signs of cervical myelopathy, and, in some cases, vascular insufficiency symptoms secondary to arterial compression.
Key References
- CKS - Neck pain - non-specific
- CKS - Neck pain - whiplash injury
- CKS - Neck pain - cervical radiculopathy
- NG232 - Head injury: assessment and early management
- (Giussani et al., 2018): Cerebral and occipito-atlanto-axial involvement in mucopolysaccharidosis patients: clinical, radiological, and neurosurgical features.
- (Ferrante et al., 2019): The Craniovertebral Junction in Rheumatoid Arthritis: State of the Art.
- (Wang et al., 2024): Posterior Circulation Ischemic Stroke From Atlantoaxial Instability and Lateral Dislocation due to Os Odontoideum: Case Report and Review of Literature.