THE RELATIVE CONTRIBUTION OF DISC AND VERTEBRAL MORPHOMETRY TO THE ANGLE OF KYPHOSIS IN ASYMPTOMATIC SUBJECTS

In order to investigate the relative contributions of vertebra and int er-vertebral disk to kyphosis, a series of 100 asymptomatic healthy wo men (age range 39-91 years) were studied to evaluate lateral dorsal ap pearances and possible related parameters of bone loss, Subjects under went lateral dorsal spine radiography and single photon absorptiometry of the radius, There was a significant decrease in physical height in relation to age (P<0.001) and this was directly related to an increas ing thoracic kyphosis (P<0.005), The angle of kyphosis was better rela ted to the average anterior disc height (P<0.001) than to average ante rior vertebral height, The vertebral body ratio, however (anterior/pos terior height), was more strongly related to angle of kyphosis than wa s disk ratio, The results also showed a fall in the proximal and dista l radial bone mineral content with age (P<0.001), These findings sugge st that dorsal kyphosis as part of the aging process may be as closely related to the physical integrity of the disc as to the vertebral bod y, Hence, therapy for age related bone mineral loss may have limited e ffect on a kyphotic deformity of the dorsal spine in otherwise asympto matic patients.