Intervertebral motion during vibration.
Artikel i vetenskaplig tidskrift, 1991

Vibration exposure is widely recognized as a risk factor for low back pain. An experimental protocol was designed to quantify the intervertebral motion response in human subjects to sinusoidal vertical vibration at 5 and 8 Hz, and at a variety of acceleration levels. Intervertebral motion in the mid-sagittal plane was measured using a transducer linkage system attached to pins placed directly into the spinous processes of adjacent vertebrae. The postures of the subjects were carefully controlled. The effects of forward flexion, arm support, gravitational load, and sitting on a cushion were evaluated. The rigid body motion of the superior vertebra with respect to the inferior vertebra was expressed in terms of relative sagittal plane rotation, axial translation, and anterior-posterior shear translation. It was found that the lumbar motion segments exhibited coupled periodic behaviour in response to sinusoidal vertical vibration, with up to 1 mm peak-to-peak displacement in the axial direction. The greatest intervertebral motion occurred when the subject was exposed to 5 Hz vibration as compared to 8 Hz. For a constant frequency of 5 Hz excitation, the peak-to-peak amplitudes of the computed motions tended to increase as the acceleration level increased. In the flexed posture, with no arm support, the active trunk musculature helped reduce the intervertebral motion. Additional gravitational load on the shoulders caused increased relative axial displacement. A polyethylene foam cushion placed on the seat reduced vibration transmission at 5 Hz excitation and consequently decreased the intervertebral motion.

Risk Factors

physiology

Intervertebral Disk

adverse effects

Biomechanics

physiology

physiology

Female

physiology

Adult

etiology

Movement

Posture

Vibration

Back Pain

Lumbar Vertebrae

Humans

Reference Values

Författare

M H Pope

Allison Kaigle Holm

Göteborgs universitet

H Broman

Tommy H. Hansson

Göteborgs universitet

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

0954-4119 (ISSN)

Vol. 205 1 39-44

Ämneskategorier

Kirurgi

PubMed

1670074