Prediction of deformity in spinal tuberculosis

Tuberculosis of the spine may cause kyphosis, which may in turn cause late paraplegia, respiratory compromise, and unsightly deformity. Surgical correction therefore may be considered for large or progressive deformities. We retrospectively analyzed clinical and radiographic parameters to predict the final kyphotic angle in spinal tuberculosis and to identify patients at risk of unfavorable outcomes at an early stage of the disease when surgery may be indicated. Unfavorable outcome was defined as progression of 10 degrees or greater and/or a final angle of 40 degrees or greater. We analyzed 53 patients with active spinal tuberculosis located in the thoracic (T1 to T10) and thoracolumbar spine (T11 to L2) and with initial kyphotic angles less than 40 degrees. We calculated the indexed total bone height loss, a value of 1 being the equivalent of the loss of a total vertebral body. There were no independent predictors. A bone height loss greater than 0.3 on the initial radiograph in combination with a thoracolumbar location indicated a 38% chance of unfavorable outcome versus only a 3% chance of unfavorable outcome when bone height loss was 0.3 or less in combination with a thoracic location. We present a simple and clinically useful algorithm for predicting kyphosis in spinal tuberculosis.