Cervical canal stenosis

Cervical canal stenosis is a general term that refers to the abnormal narrowing of the cervical spinal canal that compromises the nerve root and/or spinal cord resulting in radiculopathy and/or compressive myelopathy. The most common cause of cervical spinal canal stenosis is age-related degenerative changes, followed by acquired and congenital etiologies.

Epidemiology

Cervical spinal canal stenosis carries a reported prevalence rate of 1 in 1000 persons over 65 years of age and 5 in 1000 persons over the age of 50 in North America. There is a male predominance ⁹.

Risk factors

Risk factors include ⁹:

• rheumatoid arthritis

• osteoarthritis

• degenerative disc disease

• repetitive microtrauma

• poor ergonomics

Clinical presentation

Patients with cervical spinal canal stenosis may be asymptomatic or present with neurological symptoms predominantly affecting the upper limbs and include ⁹:

• arm or hand clumsiness

• loss of hand dexterity

• chronic neck pain

• progressive loss of fine motor function of the hands

• weakness of the upper limbs

• decreased or absent sensation of the arms or hands

• gait abnormality

• hyperreflexia

• weakness of the proximal lower extremities

Pathology

Cervical spinal canal stenosis in the setting of age-related degeneration is caused by ^9,10:

• intervertebral disc degeneration causing disc herniation and direct compression of the dural sac

• facet joint degeneration causing joint instability and hypertrophy, which worsens the degree of dural sac compression

• capsule and ligament thickening, and osteophytic and cystic changes further worsen the degree of compression

Cervical radiculopathy is caused by cervical canal stenosis at the level where the nerve roots exit the cervical spine and are commonly in the setting of disc herniation and/or facet joint hypertrophy.

Cervical myelopathy is caused by cervical canal stenosis leading to direct compression of the spinal cord. It can be associated with vascular compression with arterial involvement resulting in ischemia or venous involvement resulting in stasis. Chronic compression of the spinal cord results in inflammatory changes and edema and manifests clinically as a progressive decline of upper limb neurological function.

Etiology

The etiology of cervical spinal canal stenosis is divided into congenital or acquired etiologies.

Congenital etiologies include ^9,10:

• achondroplasia

• anterior vertebral beaking or wedging

• early vertebral arch ossification

• thoracolumbar kyphosis

• vertebral segmentation failure

Acquired etiologies can be sub-classified into degenerative, systemic, infectious, traumatic, and iatrogenic etiologies and include ^9,10:

• degenerative

  • disc degeneration

  • hypertrophy of the facet joints

  • hypertrophy of the ligamentum flavum

  • ligamentum flavum ossification

  • ligamentum flavum calcification

  • posterior longitudinal ligament ossification

  • stenosis secondary to disc herniation

  • spondylolisthesis

  • spondylosis

  • scoliosis

• systemic

  • Cushing syndrome

  • acromegaly

  • hyperparathyroidism

  • ankylosing spondylitis

  • Paget's disease

• iatrogenic

  • previous spinal fusion

  • previous spinal instrumentation

• infectious

  • osteomyelitis

• traumatic

Radiographic features

Plain radiograph

The canal-to-body ratio of Torg and Pavlov can be used to determine the presence of cervical canal stenosis ^1-3.

MRI

On T2-weighted sagittal images, the Kang grading system can be used to classify cervical spinal canal stenosis based on the severity of spinal cord compression ⁸.

The Muhle staging system can also be used to grade cervical spinal canal stenosis. The Muhle staging system utilizes a special device that facilitates T1- and T2-imaging of the cervical spine in positions from 50° of flexion to 30° of extension ⁷.

Treatment and prognosis

The objective of treatment of cervical spinal stenosis is based on two tenets, which are symptom control and further neurological and functional decline. These two tenets are used to guide decision-making in pursuing conservative or operative management.

Conservative management includes ^9,10:

• physiotherapy

• analgesics including acetaminophen and nonsteroidal anti-inflammatory drugs

• cervical spine bracing

• corticosteroid injection

• pulsed radiofrequency treatment

Operative management includes ⁹:

• anterior approach discectomy or corporectomy

• posterior approach laminectomy or laminoplasty

Complications

Cervical spinal canal stenosis can lead to:

• pain

• radiculopathy

• myelopathy

Differential diagnosis

• ankylosing spondylitis

• epidural, subdural, or intradural abscess

• conversion disorder

• rheumatoid arthritis

• diffuse idiopathic skeletal hyperostosis (DISH)