chiropractic<\/a> manipulations. The ability to quantify in vivo spine\u00a0 segment \u201ckinematics\u201d is clinically significant in terms of both the\u00a0 diagnosis and treatment of spinal disorders and LBP. The objectives of\u00a0 this study were to a) study the relative motions of the normal and\u00a0 abnormal lumbar spine in response to transverse (postero-anterior)\u00a0 manipulative thrusts, and b) mathematically model the dynamic\u00a0 viscoelastic behavior of the spine.<\/p>\nMethod:<\/h4>\n
An intervertebral motion measuring device (IMD) was\u00a0 used to quantify the in vivo Interspinous kinematic behavior of the\u00a0 normal (1 volunteer) and unstable (2 patients with abnormal lumbar discs\u00a0 consulting for spine surgery) human lumbar spine. The IMD is a spatial\u00a0 linkage system capable of measurement of motion in the sagittal plane,\u00a0 and was rigidly attached to the L2-L3 and L3-L4 spinous processes using\u00a0 2.4 mm Steinmann pins. Rotation, translation and shear of the lumbar\u00a0 vertebrae were obtained in response to transverse impulses from an\u00a0 Activator adjusting instrument (AAI) applied to the spinous process of\u00a0 adjacent segments of the thoraco-lumbar spine with the patients lying\u00a0 prone. Impulse force and acceleration in transverse plane were measured\u00a0 using a uniaxial load cell and accelerometer.<\/p>\n
Results:<\/h4>\n
The impulses (= 100N peak, < 100 msec duration)\u00a0 produced exponentially damped oscillations in the lumbar motion segment\u00a0 with displacement amplitude peaks (axial=0.5-1.0 mm, shear = 0.1-0.3 mm,\u00a0 rotation=0.5-1 degrees) located at frequencies ranging from 10-15 Hz.\u00a0 Alterations in the propagation of the impulse stimulus were observed in\u00a0 the two patients with disc pathology. The kinematic data is currently\u00a0 being analyzed using a dynamic, three-parameter linear solid\u00a0 viscoelastic model to obtain intrinsic properties of the: \u2018spine (moduli\u00a0 or stiffness and viscosity).<\/p>\n
Conclusions:<\/h4>\n
Although this study was conducted using\u00a0 only a few human subjects, the preliminary results suggest that one may\u00a0 be able to discriminate between normal and abnormal kinematic behavior\u00a0 by measuring and analyzing the impulse response. of the spine in viva.\u00a0 Such measurements may be used to evaluate the mechanical effectiveness\u00a0 of various manipulative, surgical and rehabilitative procedures of the\u00a0 spine.<\/p>\n
\nReference: <\/strong>T. Keller, PhD, M. Nathan, MS, and A. Kaigle,\u00a0 MS Dept. of Mechanical Engr. University of Vermont. Burlington, VT and\u00a0 Depts. of Orthopedics (Occupational Unit), Sahlgren Hospital, Goteborg,\u00a0 Sweden.\u00a0Proceedings of the FCER\u2019s 1993 International Conference on Spinal\u00a0 Manipulation. Montreal, Quebec, Canada, April 30-May 1: pp. 51-5.<\/p>\n