Centrode patterns and segmental instability in degenerative disc disease.

Moiré fringes were used to determine centrode patterns in cadaveric spines with degenerative disc disease. The normal centrodes were compared with those with minor, mild, moderate, and severe degenerative disc disease. The most complex loci noted were those discs that showed minimal radiographic evidence of degeneration, that is, the minor and mild groups. The loci lengthened significantly (P less than 0.001) when compared with normal controls. The position of the centrode shifted downward into the body of L5 in the moderate group.