Study design: A retrospective clinical study for prognostic purposes.
Objective: To study the morphological changes that dictate the variable progression of childhood spinal tuberculosis.
Summary of background data: Posttuberculous kyphosis in children either improves or deteriorates during growth. Associated morphological changes in the kyphosis fusion mass and the uninvolved adjacent levels have not been described in literature.
Methods: The study group consisted of 61 children with 63 spinal lesions selected from a prospective multicenter clinical trial. These children were followed up for a uniform period of 15 years at regular intervals. Anterior and posterior heights of the kyphosis fusion mass were measured. Relative difference in anteroposterior growth was analyzed by calculating the anteroposterior ratio of heights. Wedge angle and height-width ratio of uninvolved adjacent vertebrae along with changes in the morphology of disk spaces above and below the lesion were also analyzed.
Results: An increase in the anteroposterior ratio of kyphosis fusion mass leading to a decrease in kyphosis was seen in 30 lesions. A decrease in the anteroposterior ratio leading to an increase in kyphosis was noticed in 16 lesions. Overgrowth of the kyphosis fusion mass resulting in formation of large vertebral bodies was noticed in 7 lesions. No change was noticed in 10 lesions. Interestingly, changes were also noticed in 234 adjacent vertebral bodies uninvolved by the disease process: anterior wedging (n = 53), growth alteration of ring apophysis (n = 26), decrease in anteroposterior diameter (n = 26), longitudinal overgrowth (n = 40), attrition at the point of contact resulting in irregular bodies (n = 44), and posterior wedging in the region of compensatory curve (n = 45). Changes in disk spaces were noted at 136 levels, the most common finding being an opening of the disk space anteriorly (n = 126) due to formation of compensatory lordotic curves. The secondary changes leading to an increase in deformity were observed significantly more in lesions with a deformity angle of more than 30 degrees and a vertebral body loss of more than 1, and in lesions of the thoracolumbar region. Children younger than 10 years differed from those 11 years or older by having a significantly more severe disease and more number of morphological changes with growth in both the fusion mass and the adjacent segments.
Conclusions: Notable morphological changes occurred in both the kyphosis fusion mass and the uninvolved levels above and below the lesion in children with healed spinal tuberculosis. These changes occurred during growth, after complete healing of the disease was achieved, and were responsible for the variability in progression of the deformity during growth seen in these children. Our results imply that all children with spinal tuberculosis must be followed up regularly till the entire growth potential is completed.