Spinal shrinkage as a parameter of functional load.

Abstract

This article reviews the possibilities of spinal shrinkage in ergonomic evaluation of working situations. Because long-term health effects due to spinal loading are difficult to assess, short-term effects of spinal loading, such as spinal shrinkage, are used to obtain insight in the workload and its consequences, based on an assumed predictive value regarding health effects. The mechanism underlying spinal shrinkage (i.e., loss of motion segment height) and its possible relationship to low back pain, the way in which spinal shrinkage has been measured in vivo, and some results of in vivo studies are discussed. Conclusions are drawn on the validity and applicability of spinal shrinkage in ergonomic evaluations. The validity needs further investigation in relation to the loads imposed on the spine, the capacity of the worker, and the health consequences.