Journal of manipulative and physiological therapeutics
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J Manipulative Physiol Ther · Sep 1994
Measurement and analysis of the in vivo posteroanterior impulse response of the human thoracolumbar spine: a feasibility study.
To (i) measure lumbar intervertebral motion patterns produced during low force, high frequency posteroanterior (PA) thrusts applied to adjacent thoracolumbar spinal segments; (ii) determine the dependence of PA stiffness and impedance characteristics of the thoracolumbar spine on loading frequency; and (iii) ascertain the feasibility of using PA stiffness or impedance to characterize the in vivo mechanical response of the spine during spinal manipulation. ⋯ In vivo kinematic measurements of the normal and pathologic human lumbar spine indicate that low force, PA impulses produce measurable segmental motions and reinforce the notion that mechanical processes play an important role in spinal manipulation and mobilization. Calculations of the peak dynamic stiffness derived from impedance vs. frequency measurements indicate that the dynamic stiffness of the thoracolumbar spine is considerably greater than previously reported stiffness values obtained using static and quasistatic manipulation and mobilization procedures. Computations of spinal input impedance are relatively simple to perform, can provide a noninvasive measure of the dynamic mechanical behavior of the spine, appear to have potential to discriminate pathologic changes to the spine, and warrant further study on a larger sample of normals and patients. Ultimately, chiropractic clinicians may be able to use low force, impact type spinal manipulation, together with dynamic impedance analysis procedures, to quantify the mechanical response of the normal and abnormal spine, to perform spinal diagnosis and subsequently to prescribe therapeutic treatment to patients.