Changes in Vertebral Artery Hemodynamics Associated With McKenzie Therapeutic Cervical Movements: An Exploration...

The purpose of this study was to explore vertebral artery hemodynamic changes associated with McKenzie therapeutic cervical movements in healthy individuals.

A single-group repeated-measure design was used to examine 20 healthy participants aged 22.05 (1.69) years, mean (standard deviation). Vertebral artery volume flow, diameter, resistive index, time-averaged maximum velocity, and pulsatility index were measured using Duplex ultrasound. Vertebral artery hemodynamics were measured at cervical neutral positions then compared against vertebral artery hemodynamics measured during end-range loading and after repeated McKenzie therapeutic movements. Wilcoxon signed rank tests were used for comparisons, and standardized mean differences (SMDs) were calculated to quantify the changes in size.

Repeated retraction with extension in a sitting position and end-range retraction with extension in supine position were significantly associated with an increase in vertebral artery volume flow, P ≤ .01, and the SMD suggests small-medium changes in size. Statistical significant vertebral artery dilation was observed in the sitting position with protraction, combined retraction with extension, and flexion, P ≤ .01, yet the SMD suggested small changes in size. End-range flexion was significantly associated with a reduction in vertebral artery pulsatility index, and the SMD suggested large changes in size. Repeated retraction with extension in supine position was significantly associated with an increase in vertebral artery time-averaged maximum velocity, yet the SMD revealed no clinically important difference.

For the healthy participants in this study, McKenzie cervical movements were mostly associated with an increase in vertebral artery hemodynamics.