The influence of sagittal cervical profile, gender and age on the thoracic kyphosis.

The objective of this prospective consecutive cohort study was to investigate the effect of sagittal cervical profile, gender and age on the thoracic kyphosis in 228 subjects, mainly adults, free of spinal complaints and with a thoracic kyphosis of less than 500. The subjects, who were actually treated for lower extremity problems, were divided into two groups: the 68 subjects in group 1 (30%) had loss of cervical lordosis, while the 160 subjects in group 2 (70%) had a physiological cervical lordosis. In group 1 (loss of cervical lordosis) the mean angles of the upper (T1T6), lower (T7T12), and whole (T1T12) thoracic kyphosis were 8 degrees +/- 2 (range: 3-28 degrees), 15 degrees +/- 4 (range: 6-400), and 24 degrees +/- 6 (range: 10-46 degrees), respectively. In group 2 the normal cervical lordosis seemed to lead to a compensatory increase in these values: 13 degrees +/- 4 (range, 4-35 degrees) (p = 0.008), 21 degrees +/- 5 (range: 6-45 degrees) (p = 0.012), and 34 degrees +/- 8 (range: 12-50 degrees) (p = 0.007). In both groups gender had no significant effect on the values of the thoracic kyphosis (p> 0.05). Also age had no influence, neither in group 1 nor in group 2 as a whole, but in group 2 advanced age (> 50 years) was correlated with a significant increase in the lower (T7T12) (p = 0.009) and whole (T1T12) thoracic kyphosis (p = 0.007). This study yields standards for reference for the normal curvatures of the spine in the sagittal plane. The literature is quite controversial on this matter.