Erhardt JW, Windsor BA, Kerry R, et al. The immediate effect of atlanto-axial high velocity thrust techniques on blood flow in the vertebral artery: a randomized controlled trial [published online March 2, 2015]. Manual Ther. 2015;20(4):614-622. doi:10.1016/j.math.2015.02.008.
Relevant to concerns about the safety of cervical spine manipulation, physical therapy researchers conducted a single-blind randomized controlled trial on 23 healthy participants aged 27 to 69 years. In this study, 14 women and 9 men were randomly assigned to an intervention group (n=11) or a control group (n=12). Exclusion criteria were a history of known vertebral artery anomalies; hypoplasia or previous injury; undiagnosed dizziness; hypertension (≥140/90 mm Hg); head or neck trauma within the past 6 weeks; known upper or midcervical instability; recent cervical spine high-velocity, low-amplitude therapy; previous cervical spine surgery or cerebrovascular events of any kind; pregnancy; use of systemic steroids or anticoagulants; cancer; Down syndrome; Klippel-Feil syndrome; Erlos-Danlos syndrome; or if the atlantoaxial section of the vertebral artery could not be visualized on ultrasound.
The outcome measures were assessed with color flow Doppler ultrasound. The measures were hemodynamic markers of peak systolic velocity and end diastolic velocity (EDV). Secondary measures were mean velocity and a resistance index. The ultrasound transducer was held in place over the C1-C2 area throughout the procedure on all participants at 60° or less to ensure accurate measures.
The manipulation for the intervention group was to the atlantoaxial joint. The operator placed a finger over the posterior-superior aspect of the transverse process of C1 and thrusted in an anterior-inferiormedial direction to the left and then returned the head to neutral. In the control group, the same setup was followed except that no thrust was applied and with the starting position held momentarily and then the head was repositioned to neutral. This description of the intervention is similar to high-velocity, low-amplitude procedures.
The continuously measured hemodynamic markers showed no statistical difference within or between the intervention and control groups on all the measures (ie, peak systolic velocity, EDV, mean velocity, and resistance index) (P<.01). Two markers, EDV and resistance index, at the prethrust point were statistically significant (P<.05). However, this finding was not hemodynamically notable because the change was less than 25%, the cutoff for clinical relevancy.
The authors conclude that this finding adds to the building evidence for the safety of cervical spine manipulation with regard to vertebral artery derangement. As a contributor in the past decade to the American Osteopathic Association’s efforts to evaluate the safety and efficacy of cervical manipulation, I believe the safety issue is well established.
© 2015 American Osteopathic Association
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