Study design: Intradiscal pressure and intersegmental rotation of human lumbar spines were measured in vitro.
Objectives: To determine the effect of a follower load on mechanical behavior at all levels of the lumbar spine.
Summary of background data: Different loads have been proposed for studying the mechanical behavior of the lumbar spine. The influence of a follower load on intradiscal pressure at the different levels is unknown.
Methods: Ten human cadaveric lumbar spines were loaded in the three main anatomic planes with pure moments of 3.75, 7.5, and 7.5 Nm plus a follower load of 280 N. Intradiscal pressure and intersegmental rotation were measured at all levels.
Results: An additional follower load increased the intradiscal pressure, slightly reduced the intersegmental rotation for axial rotation, and hardly affected intersegmental rotation for lateral bending and flexion-extension.
Conclusions: A superimposed follower load renders spinal loading with pure moments more physiologic.