Clin Biomech (Bristol, Avon). 2014 Dec;29(10):1099-107. doi: 10.1016/j.clinbiomech.2014.10.004. Epub 2014 Oct 23.
Quantifying strain in the vertebral artery with simultaneous motion analysis of the head and neck: A preliminary investigation.
Piper SL1, Howarth SJ1, Triano J1, Herzog W2.
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Abstract
BACKGROUND:
Spontaneous vertebral artery dissection has significant mortality and morbidity among young adults. Unfortunately, causal mechanisms remain unclear. The purpose of this study was to quantify mechanical strain in the vertebral artery while simultaneously capturing motion analysis data during passive movements of the head and neck relative to the trunk during spinal manipulation and cardinal planes of motion.
METHODS:
Eight piezoelectric crystals (four per vertebral artery) were sutured into the lumen of the left and right vertebral arteries of 3 cadaveric specimens. Strain was then calculated as changes in length between neighboring crystals from a neutral head/neck reference position using ultrasound pulses. Simultaneously, passive motion of the head and neck on the trunk was captured using eight infrared cameras. The instantaneous strain arising in the vertebral artery was correlated with the relative changes in head position.
FINDINGS:
Strain in the contralateral vertebral artery during passive flexion-rotation compared to that of extension-rotation is variable ([df=32]: -0.61