Pathological studies on calcification of the intervertebral discs.

Calcified deposits in the intervertebral discs of 35 cadavers microradiographically appeared as linear of flake-like densities composed of calcium pyrophosphate dihydrate (CPPD) crystals and as multiple punctates possibly composed of dicalcium phosphate dihydrate (DCPD) crystals. Calcium deposits were found in 57% of the cadavers by microradiography and 63% by light microscopy, without known metabolic or familial history related to articular chondrocalcinosis. By scanning electron microscopy, CPPD crystals were mainly rod-like, rectangular and cuboid and were about 4 to 10 mu in length while DCPD crystals were prismatic and about 20 to 60 microns in length.