The cases of ninety patients who had tuberculous lesions in the thoracic
and thoracolumbar spine were studied. A comparison of the angles of the
gibbus deformity at onset and six years later showed statistically
significant differences between the patients who underwent treatment by
radical surgery and those who underwent treatment by one of two
non-surgical regimens. Analysis of the amount of the initial loss of
vertebral body and of the final angle of the gibbus deformity at six years
showed a correlation coefficient of 0.83. Using the formula y = a + bx, the
final angle of the gibbus deformity was predictable with 90 per cent
accuracy in the patients who were not treated surgically. The ability to
predict the final angle of the gibbus deformity allows the surgeon to
select the patients who will require radical resection and bone-grafting to
prevent a severe kyphosis.