In vivo deformability of human lumbar spine segments in pure centric tension measured during traction bath therapy

Abstract

In vivo tensile deformability of human lumbar spine segments has been measured during the usual traction bath hydrotherapy of patients when the effect of muscles can be excluded, and the lumbar spine is subjected to pure centric tensile load. Elongations of segments LIII-IV, LIV-V and LV-SI have been measured by using a special computerised subaqueous ultrasound measuring method developed by the authors. Influence of biomechanical parameters, aging, sex, body weight and height, body mass index (BMI) has been established; moreover, time-dependence of deformability has also been measured. The aim of the experiments was double: partly to clear the tensile effect of the traction bath therapy, and partly to obtain the in vivo numerical traction model of human lumbar motion segments. This report deals with the in vivo tensile deformability of lumbar segments only. The biomechanical parameter analysis and the time-dependent numerical creep model of human lumbar spine segments will be reported in forthcoming papers.