Progression of kyphosis in tuberculosis of the spine treated by anterior arthrodesis.

The case of eighty-one patients who had tuberculosis of the spine that was treated by debridement and anterior arthrodesis were reviewed eight years or more postoperatively. We studied the progression of the kyphosis and evaluated the function and fate of the bone grafts that were used. At eight years, the results with respect to the progression of the kyphosis were classified as excellent or good in forty-eight patients (59 per cent), all of whom had had minimum destruction of the vertebral bodies; limited surgical excision of bone, resulting in a small post-debridement defect that needed only a short graft; marked intraoperative correction of the deformity; and involvement of lower lumbar segments. Fifteen patients (19 per cent) had a fair result and eighteen (22 per cent), a poor result. An increase in the deformity was common in patients who had extensive involvement of the vertebral bodies that had resulted in a large post-debridement defect necessitating a graft spanning more than two disc spaces. Lesions of the thoracic vertebrae were associated with many of the poor results, and patients who had a marked kyphosis before treatment also did not do well. A stable graft that provided structural support was observed in only thirty-three patients (41 per cent), and failure of the graft due to slippage, fracture, absorption, or subsidence was seen in forty-eight patients (59 per cent). The length of the graft also played a role: the graft failed most often in patients in whom it spanned more than two disc spaces. We concluded that it is unwise to rely solely on the graft to prevent vertebral collapse in patients in whom the length of the graft exceeds two disc spaces. These patients may benefit from additional measures, such as an extended period of non-weight-bearing, posterior arthrodesis after six to twelve weeks, and prolonged use of a brace until complete consolidation is evident.