Cervical Stenosis

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Definition/Description

Cervical stenosis is a condition characterized by the narrowing of the spinal canal in the neck region. This narrowing can lead to compression of the spinal cord and/or nerve roots, potentially causing symptoms associated with cervical radiculopathy (nerve root compression) or cervical myelopathy (spinal cord compression). The condition is more common in adults over 50 years old and can result from various factors, including degenerative changes, traumatic injuries, inflammatory conditions, herniated discs, or tumors.

Clinically Relevant Anatomy

Relevant anatomy for cervical stenosis includes:

1. Cervical vertebrae: The cervical spine consists of seven vertebrae (C1-C7). The first two, C1 (atlas) and C2 (axis), have unique structures that allow for head rotation and nodding.
2. Spinal canal: This is the space within the vertebrae that houses the spinal cord. In cervical stenosis, this space becomes narrowed.
3. Spinal cord: The cervical spinal cord occupies a significant portion of the spinal canal, especially at lower cervical levels. At C1, it occupies about 50% of the canal, while at C6, it takes up about 75%.
4. Intervertebral discs: These act as cushions between vertebrae and can contribute to stenosis if they herniate or degenerate.
5. Ligaments: Thickening of ligaments, particularly the ligamentum flavum, can contribute to spinal canal narrowing.
6. Osteophytes: These bony outgrowths can form due to degenerative changes and contribute to stenosis.
7. Facet joints: Degenerative changes in these joints can lead to stenosis.
8. Nerve roots: These exit the spinal cord through foramina, which can be affected by stenosis, leading to radiculopathy.

Understanding this anatomy is crucial for assessing and treating cervical stenosis, as the condition's symptoms and severity depend on which anatomical structures are affected and to what degree..

See also Cervical Anatomy

Normal cervical vertebrae

Cervical stenosis

Pathophysiology

Many theories regarding the pathophysiology of spinal stenosis suggest a number of confluent mechanisms:

• The spinal cord can be directly compressed by osteophytic bones and ligamentous hypertrophy.
• Compression of local vascular structures can lead to ischemia of the spinal cord from arterial insufficiency and venous stasis.
• A herniated disk can exert repeated local trauma to the spinal cord or nerve root during repetitive flexion and extension movements, especially in the unstable spine with multiple levels of subluxations.
• In the cervical spine, segments C5-6 and C6-7 are often affected.

Epidemiology

Cervical stenosis epidemiology:

• Prevalence: 4.9% in adults, increasing with age (6.8% in 50+, 9% in 70+)
• More common in adults over 50
• Slightly higher incidence in males
• White race identified as a risk factor in some studies
• Risk factors: age, genetics, cumulative trauma, smoking, osteoporosis
• 75% of patients experience neurological deterioration phases
• 5% of asymptomatic cases become symptomatic annually
• Most commonly affects C5-C6 and C6-C7 segments
• Majority of cases have uneventful recovery without surgery.

Etiology

Cervical spine stenosis can be caused by a combination of factors.

• Some individuals can have a congenitally narrowed spinal canal that is exacerbated by pathologic factors.
• Disk herniation together with the formation of osteophytic spurs, hypertrophy of the articular facets and ligamentum flavum, and ossification of posterior longitudinal ligaments can lead to central and foraminal stenosis.
• Structural factors such as subluxation from disk and facet joint degeneration and changes in the normal lordotic curvatures of the spine can lead to spinal compression.

Characteristics/Clinical Presentation

Characteristics/Clinical Presentation of cervical stenosis:

1. Pain: Often in neck, may radiate to arms or shoulders
2. Radiculopathy symptoms:
   • Numbness, tingling, or weakness in arms or hands
   • Shooting pain down arm
3. Myelopathy symptoms:
   • Gait disturbances
   • Balance problems
   • Fine motor skill difficulties
   • Weakness in arms or legs
   • Bowel or bladder dysfunction (in severe cases)
4. Neck stiffness or reduced range of motion
5. Headaches
6. Progression: Can be slow and steady, stabilize at a certain point, or rapidly decline
7. Symptoms may worsen with neck extension or prolonged standing/walking
8. Possible asymptomatic presentation, especially in early stages
9. Lhermitte's sign: Electric shock-like sensation down spine with neck flexion

Severity and combination of symptoms can vary widely between individuals..

Differential Diagnosis

• Diabetes
• Inflammatory spondyloarthropathy (e.g., ankylosing spondylitis)
• Peripheral neuropathy (paralysis)
• Peripheral vascular disease
• Single level lumbar disc herniation
• Spinal cord tumor
• Vascular insufficiency (atherosclerosis of the aorta and/or leg arteries)

Pathophysiology

The pathophysiology of cervical spinal stenosis involves:

1. Direct compression of the spinal cord by osteophytes and ligamentous hypertrophy.
2. Vascular compromise: Compression of local blood vessels leading to spinal cord ischemia from arterial insufficiency and venous stasis.
3. Repetitive trauma: Herniated disks causing repeated local trauma to the spinal cord or nerve roots during flexion and extension movements, especially in unstable spines.
4. Narrowing of the spinal canal: Due to degenerative changes, disk herniation, osteophyte formation, and ligament thickening.
5. Foraminal stenosis: Narrowing of nerve root exit points, potentially causing radiculopathy.

These mechanisms often occur in combination, leading to the clinical manifestations of cervical stenosis.

Evaluation

Diagnosis of cervical stenosis typically involves:

• Medical history and neurological screening
• Physical examination
• Imaging studies:
  • MRI: Gold standard, reveals intrinsic cord abnormalities and degree of stenosis
  • CT: Useful for bone detail, alternative when MRI is contraindicated
  • X-rays: Limited value, but can show dynamic instability in flexion/extension views
  • CT myelogram: Alternative when MRI is not possible
• Differential diagnosis to rule out other conditions with similar symptoms
• Assessment of neurological findings (myelopathy or radiculopathy)
• Use of outcome measures like Neck Disability Index and Neck Pain and Disability Scale

Definitive diagnosis requires imaging, with MRI being the preferred technique to determine the level and degree of stenosis.

Outcome Measures

• Neck Disability Index
• Neck Pain and Disability Scale

Medical Management

Medical management of cervical stenosis typically includes:

1. Conservative approaches:
   • Physical therapy: Stretching, strengthening, and aerobic exercises
   • Anti-inflammatory and analgesic medications
   • Epidural steroid injections
2. Activity modification and ergonomic adjustments
3. Cervical collar for short-term immobilization
4. Muscle relaxants
5. Traction (in some cases)
6. Patient education on posture and body mechanics
7. Regular clinical follow-ups for non-myelopathic patients
8. Surgical intervention:
   • Reserved for patients who fail conservative treatment
   • Considered for significant disability or progressive neurological deficits
   • Urgent surgery for rapidly progressing deficits or bladder dysfunction

The goal is to alleviate symptoms and improve function rather than prevent neurological complications. Surgery is generally not recommended for asymptomatic patients with cord compression.

Physical Therapy Management

Nonoperative treatments, such as physical therapy management, are aimed at reducing pain and increasing the patient's function. Nonoperative treatments do not change the narrowing of the spinal canal, but can provide the patient of a long-lasting pain control and improved function without surgery. A rehabilitation program may require 3 or more months of supervised treatment.

A physical therapy program may include)

• Stretching exercises: These exercises are aimed at restoring the flexibility of the muscles of the neck, trunk, arms and legs.
• Manual therapy: Cervical and thoracic joint manipulation to improve or maintain the range of motion.
• Heat therapy: to improve blood circulation to the muscles and other soft tissues.
• Cardiovascular exercises for arms and legs: This will improve blood circulation and enhance the patient's cardiovascular endurance and promote good physical conditioning.
• Aquatic exercises: to allow your body to exercise without pressure on the spine.
• Training of activity of daily living (ADL) and functional movements.

Exercises and techniques that may help relieve symptoms of spinal stenosis and prevent progression of the condition include:

• Specific strengthening exercises for the arm, trunk and leg muscles.
• Stretching
• Postural re-education
• Scapular stabilization
• Ergonomics and frequent changes of position, to avoid sustained postures that compress the spine
• Planning ahead so that you take breaks in between potentially back-stressing activities such as walking and yard work.
• Proper lifting, pushing, and pulling.

Prognosis

Spinal stenosis has significant morbidity and affects the quality of life. With time it can lead to chronic pain and muscle weakness. In some cases, it may lead to cauda equina syndrome. Patients with central spinal stenosis may have difficulty walking and have gait disturbances. While some patients may improve with time, the majority have a progression of the condition, leading to disability. The cost of managing spinal stenosis is enormous, and for patients can lead to high healthcare bills.