Database for Estimating Normal Spinal Motion Derived from Non-Invasive Measurements
Gracovetsky SA, Pawlowsky M, Newman N, Lanzo V, Davey B, Robinson L.
Spine
20 : 1036-1046, 1995.
Abstract
Study design
A database for estimated normal spinal motion
was derived using a noninvasive, high-resolution, computer-aided system, which tracks the
motion of skin markers strategically placed on the spine. Forty normal subjects, selected
from hundreds of possible subjects according to rigorous inclusion/exclusion criteria,
were tested on the system.
Objectives
: Patterns of estimated spinal motion were
analyzed as a function of load, age, and sex, confirming a correlation between the
movement of spinal segments and the motion of skin markers.
Summary of background data
The Workers Compensation
Board of Quebec funded and supervised the experiments necessary to establish a normative
reference database for a high-resolution motion analysis system that permits a noninvasive
assessment of spinal function. A previous study examined the correlation between the
movements of the skin markers and the underlying bony structures for trunk flexion. Skin
movement cannot be random and contains information characterizing both the spine and its
surrounding soft tissues.
Methods
A noninvasive dynamic imaging system was used to
measure normal spinal function under free movement. A high- resolution three-dimensional
camera system collected basic kinematic data from strategically placed skin markers over
the lumbar spine while the activity of paraspinal muscles was being recorded with surface
electromyography. The measurements were analyzed for consistent, specific patterns
recognizable as normal lumbar spine skin motion and reflecting normal lumbar spine
function. A comparison was made with previous radiographic studies to confirm the
correlation between the motion of skin markers and lumbar spine function.
Results
Lumbar skin marker motion patterns in normal
subjects were consistent and varied little with load; gender had no effect except in the
initial phase of a movement. There was less mobility but similar coordination in older
subjects. No inconsistencies with previous radiologic investigations were found for
sagittal and lateral plane movement.
Conclusions
Consistent patterns were found and measurements compare
favorably with previous radiographic data. Results show that it is possible to estimate
spinal function from the data collected from the motion of skin markers.
