Special Tests: Upper Cervical Spine Instability and Vertebrobasilar Insufficiency (VBI)

Special Tests Covered in this Lesson:

• Upper Cervical Spine Stability Tests
  • Modified Sharp Purser Test
  • Alar Ligament Stability Test
  • Tectorial Membrane and Posterior Atlanto-occipital Membrane Test
  • Anterior Stability Test of the Atlanto-Occipital Joint
• Vertebrobasilar Insufficiency Testing
  • Vertebrobasilar Insufficiency (VBI) Test and Wallenberg's Position

Upper cervical spine instability and vertebrobasilar ischemia (VBI) are potentially serious issues that most commonly result from injury, some congenital disorders, and rarely, the degeneration of relevant tissues with the aging process. For example, Ehlers-Danlos Syndrome (EDS) is a connective tissue disorder that can result in laxity of the transverse ligament, tectororial membrane, or alar ligament, resulting in craniocervical instability and an increase in the risk symptoms like nerve root compression with axial rotation. Additionally, a fall that involves landing "on the neck", or a fall that involves a concussive force to the head, in rare cases can result in cervical spine injury that disrupts the connective tissue structures of the upper cervical spine or the dens of the axis. Unfortunately, this may initially result in only neck pain, despite surgical repair being necessary to prevent potential spinal cord injury. Note, there is no evidence that chiropractic care is a common cause of cervical instability or cervical injury, especially those injuries resulting from VBI (More information available in the course linked below). Although chronic neck pain can be an indicator of craniocervical instability and/or VBI, most often injury or diagnoses of congenital disorders precede these diagnoses. Special tests for these conditions have poor sensitivity, but high specificity, so their use as a screen is not recommended. The special tests for these conditions likely only have minimal utility to confirm a diagnosis indicated by prior history (head injury), testing (imaging), or symptomatology (neurological signs).

Best-practice Recommendations:

• "Clear" the Patient/Client for Intervention: The gross majority of special tests are only helpful for clearing the patient for intervention, and do not have an impact on intervention selection. The Brookbush Institute is adamant that choosing interventions based on diagnosis is flawed logic, and that interventions should be selected based on the results of movement assessment . However, some diagnoses imply physical interventions are not recommended, and referral for additional testing or alternative treatments is necessary. For example, cervical spine instability, craniocervical instability, ligament laxity, connective tissue rupture, symptoms of spinal cord compression, nerve root compression (irritable radiculopathy), etc., may imply that treatment should be postponed until further testing can be performed, and/or surgery is considered.
• Highlight Contraindications: Some special tests may indicate damage to tissues and suggest that certain targeted interventions are inappropriate. For example, the special tests in this course may indicate ligament laxity, clinical instability, cervical bracing (muscle spasm), pain with certain motions, etc. These results may indicate that cervical manipulations, cervical muscle stretching, or certain high-intensity exercises are not appropriate.
• Refine Exercise/Intervention Selection: A few of these special tests could be used like movement assessments. For example, assuming that the tests did not provoke symptoms associated with a positive result, stiffness and pain with motion may be indicative that mobilization or manipulation may be beneficial, findings of increased tissue density and/or muscle spasm may indicate release techniques should be considered. And, findings of spinal instability (without additional symptoms) may indicate that cervical stabilization and deep neck flexor activation would be beneficial.

Brookbush Institute Recommendation:

• The Brookbush Institute recommends that all clinical professionals are aware of these special tests (physical therapists, physical therapy assistants, chiropractors, occupational therapists, athletic trainers, etc.). It is recommended that VBI and/or upper cervical instability tests are performed if findings during the subjective examination imply that VBI or upper cervical instability may be contributing to a patient's condition, and/or if these tests have been mandated as a screening prior to manipulation by legislation, 3rd party payer, or a licensing boards that the professional relies on. However, the Brookbush Institute cannot recommend these tests as a valid, reliable, or accurate method for screening patients who may be at risk for a serious adverse event correlated with manipulation. Note, at all times, the clinician should use reason, rationale, and professional judgment, and err on the side of caution when performing any technique that may impart an unacceptable increase in risk.

For an Introduction to Special Tests:

• For an introduction to Special Tests including definitions of specific terminology, what special tests measure, accuracy (specificity, sensitivity, reliability, etc.), how we chose the tests in each special test course lessons, and best practice recommendations:
• Special Tests: Introduction

Additional Special Tests for the Cervical Spine:

• Special Tests: Cervical Radiculopathy, Cervicogenic Headache, and Canadian C-spine Rules

Risk of Adverse Events following Mobilization and Manipulation:

• Joint Mobilizations and Manipulations: Risk of Adverse Events