Clinical studies on causative factors of ossification of the spinal ligaments
Omoto, H.
Nihon Geka Hokan. Archiv für Japanische Chirurgie 49(1): 53-68
1980
ISSN/ISBN: 0003-9152 PMID: 6767461 Document Number: 162047
One of the important roentgenographic features of ankylosing spondylitis and ankylosing hyperostosis is marked ossification of the spinal ligaments. The pathogenesis of ossification of the ligaments surrounding the spine is not well known. Causative factors of the ossification were studied clinically. A genetic study was made of a family with ankylosing spondylitis [AS] with emphasis on HLA-B27. This family was composed of 1 female in the 1st generation, 11 males or females in the 2nd and 20 males or females in the 3rd. Five AS cases were discovered; 1 in the 1st generation, 3 in the 2nd generation and 1 in the 3rd generation. The 83 yr old female of the 1st generation had HLA-B27, and it was inherited to the 2nd generation in 6 cases and to the 3rd generation in 3 cases. Apparently the genes controlling this disease are not limited to the euchromosome dominant genes in close proximity with HLA-B27 and X-linkage recessive genes. The disease seems to be of multigenic nature. In ankylosing hyperostosis, it was presumed that a causative factor in the ossification of spinal ligaments was Hahn's groove. A study was made of ankylosing hyperostosis and ossification of the posterior longitudinal ligaments (OPLL). Hahn's groove, rarely encountered in post youth ages, was noticeable in 30 out of 48 cases of ankylosing hyperostosis. A population study of Hahn's groove, consisting of 573 cases, was made for control purposes. Statistically the difference between ankylosing hyperostosis and the controls was significant (P < 0.001 in all ages). The same frequency of Hahn's groove was obtained in the 62 cases of OPLL. Hahn's groove is a causative factor in the ossification of the spinal ligaments. Apparently the significance of Hahn's groove, noted in ankylosing hyperostosis, is that vertebral bodies having Hahn's groove have a rich blood supply favoring the progression of ossification.