What is Cervical Spinal Canal Stenosis
Cervical spinal canal stenosis is a narrowing of the spinal canal in the neck region that can compress the spinal cord and/or nerve roots, potentially leading to myelopathy (spinal cord dysfunction) or radiculopathy (nerve root compression). 1
Anatomical Definition
The condition is defined by a reduction in the anteroposterior (front-to-back) diameter of the cervical spinal canal 2. Stenosis is typically diagnosed when the canal diameter measures less than 12 mm 3. In the general population, the average cervical canal diameter is 14.1 ± 1.6 mm, ranging from 9.0 to 20.9 mm 3.
Types of Cervical Stenosis
Congenital (Developmental) Stenosis
- Results from abnormal embryological development leading to a constitutionally narrow canal 4, 5
- Can occur at the craniovertebral junction or involve diffuse narrowing of the entire cervical canal 2
- May remain asymptomatic until adulthood when degenerative changes further narrow an already compromised canal 6
Acquired Stenosis
- More common than congenital forms 7
- May affect one to two levels (focal) or three or more segments (extensive) 2
- Caused by degenerative changes, disc herniation, osteophyte formation, ligamentum flavum hypertrophy, or systemic conditions (endocrinopathies, inflammatory diseases, Paget disease) 7
Clinical Manifestations
The narrowing itself is not the disease—stenosis only becomes clinically significant when it produces symptoms 7:
Cervical Spondylotic Myelopathy (CSM)
- Occurs when spinal cord compression causes neurological dysfunction
- Presents with motor symptoms in arms and/or legs, sensory disturbances, gait difficulties, and loss of fine motor control 8
- Most common cause of myelopathy in patients over 50 years 7
Radiculopathy
- Results from neuroforaminal stenosis compressing nerve roots
- Causes arm pain, weakness, and sensory changes in specific nerve root distributions 1
Natural History
The progression of CSM follows a mixed pattern 8:
- 75% of patients experience stepwise decline with episodes of new symptoms followed by quiescent periods
- 20% show slow, steady progression without stepwise changes
- One-third of patients may have no deterioration during quiescent intervals, and some may experience interim improvement 8
Critical caveat: Long periods of severe stenosis over many years lead to white matter demyelination and potential gray/white matter necrosis, resulting in potentially irreversible neurological deficits 8.
Epidemiology
- Cervical stenosis is very common, affecting approximately 4.9% of the adult population, 6.8% of those ≥50 years, and 9% of those ≥70 years 3
- Men have significantly larger cervical canals than women at all levels 3
- Specimens from donors ≥60 years show significantly narrower canals than younger donors 3
- Incidence of symptomatic cervical stenosis: approximately 1 case per 100,000 population 7
Important Clinical Pitfall
The radiographic finding of cervical stenosis must be correlated with clinical presentation before making treatment decisions 3. Many individuals have anatomical stenosis without symptoms, so imaging findings alone do not constitute disease requiring intervention.