[Histological changes in the ligamentum flavum in patients with spinal stenosis].

In 21 patients with spinal stenosis the ligamentum flavum was removed, histologically processed and the calcification was measured with an image analyzing computer. Nearly all the ligaments were calcified: on average 0.17%, with a maximum of 3.8%. There was a significant correlation between age and calcification. We compared these findings with those of a group of "normals". There we only found minimal calcification in 3 of 20 segments (0.025%, 0.049%, 0.22%). As these people were on average 85 years of age, this can be looked upon as normal degenerative changes. This illustrates the important role of calcification of the ligamentum flavum for spinal stenosis.