Osmotherly P.1, Folbigg S.1, Symonds J.1
1The University of Newcastle, School of Health Sciences, Callaghan, Australia
Background: The rotation stress test has been proposed as one method for assessing alar ligament integrity prior to the application of manual procedures to the upper cervical spine. Interpretation of the test in published literature is inconsistent with regard to the amount of movement which should be possible in the presence of intact alar ligaments. All authors agree that some rotation will occur during testing but the reported extent of rotation acceptable within the bounds of normal varies by up to 20 degrees.
Purpose: To examine the variation in measured range during rotation stress testing for the alar ligaments in a clinical setting and determine whether rotation range during testing is affected by patient age.
Methods: A cross-sectional study examining 88 adults ranging from 18 to 86 years with no current neck problems and no known risk factors for craniocervical instability was undertaken. Participants underwent rotation stress testing for the alar ligaments performed to each direction in neutral, flexion and extension in both sitting and supine. Cervical rotation range (degrees) during testing was recorded using an electromagnetic movement tracking system (Liberty, Polhemus, USA). Range was assessed overall and compared by 10-year age groups. Rotation range and age was assessed using Spearmans Rank correlation. Reliability of measurements was assessed by estimation of ICCs.
Results: Mean angles of upper cervical rotation ranged between 8.86° (SD 2.76°) to 17.2° (SD 5.24°). Overall measured rotation ranged from 2.34° to 33.22°. A low negative correlation was found between range of rotation and age, particularly in sitting (rho ranging from -0.15 to -0.47). Older age groups displayed less rotation, however, this was rarely statistically significant.
Conclusion(s): Normal range of rotation on stress testing for the alar ligament varies widely between individuals. Whilst all values fell within recommended ranges for ligament integrity, interpretation of the test will be problematic for people with inherently little rotation before the onset of a clinical disorder.
Implications: Considerable variation exists in the amount of craniocervical rotation occurring during the imposition of this screening test. The rotation ranges for people without alar ligament compromise all fell below the ranges recommended to flag possible instability. However, it cannot not be inferred that findings of low range of rotation necessarily represent normal ligament integrity.
Funding acknowledgements: No funding was used to support this research
Topic: Musculoskeletal: spine
Ethics approval: Ethics approval was granted by the The University of Newcastle Human Research Ethics Committee
All authors, affiliations and abstracts have been published as submitted.
