Changes in Basic Metabolic Elements Associated With the Degeneration and Ossification of Ligamenta Flava

The posterior spinal structures, including hypertrophied and ossified ligamentum flavum (LF), play a major role in the pathogenesis of spinal stenosis, which could be responsible for the compression of the spinal cord and nerve roots (1,2). The etiology of hyperplastic and ossific changes in LF remains obscure, although the release of growth factors during the repair process following ligament injury seems to be involved (3). According to Yoshida et al (2), yellow ligament (LF) hypertrophy can be ascribed to 3 mechanisms: proliferation of type II collagen, ossification, and calcium crystal deposition. The ossification of ligamentum flavum (OLF), a definite clinical entity affecting predominantly the lower thoracic spine in middle age, is viewed as a form of ectopic ossification (4–6) and has been observed in a variety of disorders of mineral metabolism, such as vitamin D–resistant hypophosphatemic rickets and fluorosis. It has been suggested that basic metabolic elements might play some roles in the degeneration and ossification of the LF. Until now, few reports have discussed the association between basic metabolic elements and the degeneration and ossification of LF. The purpose of this study is to examine the contents of calcium (Ca), phosphorus (P), magnesium (Mg), zinc (Zn), copper (Cu), manganese (Mn), molybdenum (Mo), and fluoride (F) in the LF and sera specimens from patients with thoracic OLF and degenerated lumbar stenosis to determine whether basic metabolic elements contribute to the degeneration and ossification of the LF.