The Upper Cervical Spine and Cervicogenic Headaches

Introduction

Cervicogenic headache (CGH) is a chronic secondary headache that originates in the cervical spine. The headache begins in the neck or occipital region and can refer to the face and head. The specific sources of CGH are any structures innervated by the C1 to C3 nerve roots.

When assessing and treating patients with CGH, it is important to be able to clearly identify the symptomatic area in the upper cervical spine. Areas to assess are the:

• Occipito-antlantal (OA) joint
• Atlanto-axial (AA) joint
• C2-3 joint
• Suboccipital muscles

Headache Assessment

Subjective Assessment

The subjective assessment of the cervical spine is discussed here, but when patient's report headaches, it it important to ask specifically about the:

• Intensity of headaches
• Frequency of headaches
• Duration of headaches

Any change in these parameters at follow-up assessments will help to indicate if the headache is responding as expected to management.

Objective Assessment

A full description of a cervical assessment can be found here. But when assessing for CGH, the following measures should be included:

• Range of motion testing
• Deep neck flexor endurance testing
• Palpation and joint mobility testing

Common clinical methods for assessing cervical spine mobility include:

• Flexion rotation test
• Active cervical range of motion
• Passive accessory inter-vertebral movement and physiological inter-vertebral movement (PPIM/PPIVM)
• Active cervical flexion test
• Myofascial trigger points assessment
• Ischemic pressure tolerance test
• Cervical proprioception assessment

Red Flags

It is essential to screen for red flags and serious conditions in any assessment of the cervical spine.

Specific red flags in relation to headache are:

1. Sudden onset of a new severe headache
2. A worsening pattern of a pre-existing headache in the absence of obvious predisposing factors
3. Headache associated with fever, neck stiffness, skin rash, and with a history of cancer, HIV, or other systemic illness
4. Headache associated with focal neurologic signs other than typical aura
5. Moderate or severe headache triggered by cough, exertion, or bearing down
6. New onset of a headache during or following pregnancy.

Serious conditions  include:

• Cranial artery dysfunction
  • Cervical artery
  • Carotid artery
• Intracranial issues
• Upper cervical ligament instability: LINK
  • Transverse ligament (Sharp purser test
  • Alar ligament 

Upper Cervical Ligament Instability

Upper cervical ligament instability has a prevalence rate of 0.6 percent, but it is more common in patients with inflammatory arthritis (e.g. rheumatoid arthritis). Despite low prevalence rates in the general population, it is important to screen for these conditions.

Transverse Ligament

The transverse ligament enables the atlas to pivot on the axis. It holds the atlas in its correct position in order to prevent spinal cord compression during neck and head flexion.

The Sharp Purser test is commonly used in clinical practice to assess for atlantoaxial instability, particularly in patients with rheumatoid arthritis. This test is discussed in more detail here.

Use of the sharp purser test is, however, considered contentious due to its potential to cause harm (i.e. a positive sharp purser test involves compressing the spinal cord via the dens of C2 and then performing a manoeuvre to decrease pressure on the spinal cord. This could be unsafe in high risk populations). While there is currently no evidence to suggest that this test is harmful, there is a lack of evidence on its use in high-risk populations. It also demonstrates inconsistent validity and poor inter-rater reliability.

Other tests include the transverse ligament stress test. This test has high enough specificity to rule in patients with upper cervical spine instability. However, when Hutting and colleagues looked at a range of instability tests, they concluded that it is not currently possible to accurately screen for upper cervical instability.

Alar Ligament

The alar ligaments act to stabilise the cervical spine, but can be damaged following trauma. It is important that they are assessed, particularly in patients who have neck dysfunction following injury. The gold standard test is MRI, but when this is not available, there are a number of clinical tests that can be used, including:

• Side-bending stress test
• Rotation stress test
• Lateral shear test

In a recent study, the sensitivity and specificity of these tests was found to range from 80–85.7 percent and 69.2–90.9 percent, respectively. Positive and negative likelihood ratios ranged from 2.6 to 9.41 and 0.15 to 0.26, respectively. These figures indicate that these tests are only of small-to-moderate clinical diagnostic value. However, when used as a cluster of tests, the sensitivity and specificity were to 85.7 percent and 100 percent, respectively if more than two tests were positive. Likelihood ratios improved to infinity (positive likelihood ratio) and 0.15 (negative likelihood ratio) which indicates that this cluster of tests has moderate-to-excellent clinical diagnostic value.