Cervical Radiculopathy

Introduction

• Compression of the nerve root in the neck, leading to pain, numbness, and/or tingling
• Often can be caused by a herniated disk in the neck that puts pressure on nearby nerves

Anatomy

Describe the pertinent anatomy

Pathogenesis

• Cervical radiculopathy involves an inflammatory process initiated by nerve root compression
• The compression may be from a disk herniation, degenerative changes about the neural foramen, or a combination of both
• Disk degeneration may result in radial tears and leakage of the nuclear material, which leads to further neural toxicity and symptoms, even without compression
• Neural compression by the herniated material is responsible for sensory and motor dysfunction, while radicular pain is caused by inflammation of the nerve (which can explain the lack of correlation between the size of a herniation or even the degree of neural compression and the associated clinical symptoms)
• Macrophages respond to the displaced foreign material and seek to clear the spinal canal
• Evidence has been found that inflammatory mediators are released by herniated intervertebral disks, leading to nerve root swelling
  
  • Nitric oxide
  • Prostaglandins
  • Interleukins
  • TNF-?
  • Matrix metalloproteinases
• Subsequently, a scar is produced and substance P, which is associated with pain, is detected
• Disk herniation accounts for 20-25% of the cases of cervical radiculopathy
• In the younger population, cervical radiculopathy is typically a result of
  
  • Disk herniation
  • Acute injury causing foraminal impingement of an exiting nerve
    
    • Trauma/straining/exertion are often precursors for disc herniation
    • Frequently seen with playing golf, shoveling snow, diving, or prolonged exposure to vibration; especially with driving for extended periods of time
    • While radiculopathy often occurs after car accidents, no evidence for associated disc herniation has been found
• In the older patient, cervical radiculopathy is often a result of
  • Foraminal narrowing from osteophyte formation
  • Decreased disk height
  • Degenerative changes of the unco-vertebral joints anteriorly and of the facet joints posteriorly
  • Often, there is no specific, identifiable precipitating event, suggesting that the cause is more than just a single incident of stress. It could be that there is a genetic predisposition related to the relative strength of the spinal column, that when combined with prolonged exposure to detrimental circumstances or a traumatic event, causes the disk herniation and associated radiculopathy

Risk factors

• Middle-aged and older men, although there is a drop-off after age 60
• Strenuous physical activity
• Congenital conditions affecting the size of the spinal canal
• Driving long distances due to the resonant coupling of 5-Hz vibrations from the road to the spine. Truck drivers have the additional risk of spinal problems from lifting during loading and unloading, which is frequently done after prolonged driving.

Prevention

• Safe work and leisure activity practices
• Proper lifting techniques
• Weight control

Some health care providers recommend the use of back braces to help support the spine. Such braces can help prevent injuries in people whose work requires them to lift heavy objects. However, overuse of these devices can weaken the abdominal and back muscles, making the problem worse.7

Natural History

• The annual incidence is approximately 85 per 100,000 population
• Disk herniation occurs more frequently in middle-aged and older men, especially those involved in strenuous physical activity
• According to one study, the mean age at diagnosis was 47.9 years
• Age-specific incidence rates were highest for the 50-54 year age group and declined steeply after age 60
• M:F ratio = 1.7:1
• C7 is the most frequently affected nerve around (70%), followed by C6 (20%) and then C5, C8, and T1 accounting for the last 10% 

Clinical Presentation

• Pain, numbness/loss of sensation, and tingling in the neck, shoulder and down one arm, along the path of the affected nerve root
• Pain is generally a universal sign and may be present in the neck, shoulder, or arm, independent of the others
• Paresthesia occurs in approximately 80% of patients and weakness may also be present, although it is less common
• Reduced range of motion and increased pain with motion of the neck, particularly with extension, rotation, and lateral bending
• Pain with bending away from the affected side suggests displacement of the herniated disc onto a nerve root
• Pain on bending towards the affected side suggests impingement at the neural foramen
• Typically, patients tilt their head away from the side of injury and hold their neck stiffly
• Muscle tenderness may occur along the path of referred symptoms and can have associated hypertonicity or spasm
• Onset of symptoms is most frequently acute, but in some cases can be more gradual
  

Differential Diagnosis

• Entrapment neuropathy
  • Median
  • Ulnar
• Neurologic afflictions; eg, MS
• A history of difficulty walking, lower extremity or trunk symptoms, or bowel and bladder dysfunction are suggestive of myelopathy
• A history of fever, chills, unexplained weight loss, immunosuppression, cancer, or intravenous drug use should raise suspicion for tumor or infection

Psychosocial impact of disease

• Can cause difficulties in performing daily activities, specifically with regard to lifting or carrying objects
• May make the patient either dependent on others to perform these tasks or unable to do them entirely
• May prevent the patient from being able to live independently
• Supportive devices, such as a neck brace, may make the patient feel awkward if worn in public

Imaging and Diagnostic Studies

X-ray

• Findings
  • Disk-space narrowing
  • Subchondral and foraminal sclerosis
  • Osteophyte formation
• Correlations of findings on plain radiographs and cadaver dissections have found a 67% correlation between disckspace narrowing and anatomic findings of disk degeneration
• Radiographs identify only 57% of large posterior osteophytes and only 32% of abnormalities of the apophyseal joints

CT scan

• The accuracy ranges from 72% to 91% for diagnosis of disk herniation
• CT scanning with myelography has an accuracy approaching 96%

MRI

• Test of choice for diagnosis
• Can detect ligament and disk disruption that cannot be demonstrated by other imaging studies
• However, MRI has been shown to find abnormalities in 8-20% of asymptomatic patients

Laboratory evidence

• EMG may be done to determine the exact nerve root that is involved
• Nerve conduction studies alone are not sensitive for radiculopathy, but can be useful to rule out entrapment neuropathies, such as carpal tunnel syndrome
• Myelogram may be done to determine the size and location of disk herniation

Classification

Include a list with links to relevant conditions

Treatment

Conservative management

• Initial treatment should be directed at reducing pain and inflammation
• Initial treatment
  
  • Reducing compressive forces through:
    
    • Rest
    • Positioning
    • Manual or mechanical traction
  • Local icing
  • NSAIDs
• Additional treatment may include:
  
  • Physical therapy
  • Oral corticosteroids
  • TCAs
  • Steroid injections in severe cases
• Trials have also shown possible benefits with acupuncture
• Continued physical therapy during recovery should focus on increasing flexibility and range of motion, as well as strengthening stabilizer muscles, to reduce future nerve compression

Surgical treatment

• No clear evidence that surgical treatment provides better long-term outcomes than non-operative measures in the acute phase
• Surgery is recommended for:
  • Athletes with cervical instability
  • Progressive neurologic deficits
  • Those who fail more conservative therapy
• Surgical techniques include:
  • Excision of disk fragments

• • Vertebral body fusion
    • Suitable for patients with more severe disk degeneration, particularly myelopathy
    • Interbody cages are being considered as a way of promoting more rapid rehabilitation and more consistent results 

• • Laminectomy

• • Artificial disk replacement

• • Microdiscectomy: now most common surgical treatment because it is less invasive

Outcome

• The prognosis is excellent, with 80-90% of patients improving with non-operative treatment.* Symptoms may recur in up to 1/3 of patients, despite treatment.
• Surgery is indicated when non-operative treatment has failed, but studies have shown mixed results on its effectiveness.
• One small RCT of 81 patients showed an advantage in pain reduction, muscle strength, and sensation in surgically treated patients (vs. immobilization with a cervical collar) at 4 months, but only a difference in muscle strength at 1 year.
• Two prospective studies, however, found substantial improvement in pain and weakness in approximately 75% of surgically treated patients.
  

Complications

• Spinal cord injury (<1%)
• Nerve root injury (2-3%)
• Device failure (<4%)
• Transient dysphagia (10%)
• Recurrent laryngeal nerve injury (2-3%)
• Esophageal perforation (<1%)
• Vertebral artery injury (<1%)
• Wound infection (<1%)

Pearls and Pitfalls

Tips and problems to avoid

Controversy

Include current controversies in diagnosis or treatment

References