Lifting up and laying down a weight causes high spinal loads

Abstract

Lifting up weights from a cupboard or table and putting them back are activities of daily living. Patients with spinal problems want to know whether they should avoid these activities. However, little is known about the spinal forces during these activities and about the effect of level height. Loads on a telemeterized vertebral body replacement were measured in 5 patients. The effect of level height when lifting or setting down weights of 0.01, 1.5 and 3.0 kg in a standing posture were investigated. Furthermore, these weights were lifted and set down with a stretched arm while sitting at a table. No instructions were given on how to perform the task. For these activities, forces as high as 5 times the value for standing alone were measured. In 2 patients, implant loads decreased with increasing level height. In the other patients the effect of level height was small. Lifting a weight from a table with a stretched arm while sitting led to a strong increase of the maximum implant force. Setting down the weight usually caused a slightly higher maximum implant force than lifting it. Forces on a vertebral body replacement during lifting and setting down a weight varied strongly when no precise instructions were given on how to perform the activity. Thus, the measured forces are representative for such activities performed in daily life. This, however, led to wide variations in measured data. Compared to the value for standing, 5 times higher forces were measured for lifting and setting down of weights. This suggests that these activities should be avoided by patients who have spinal problems.