Atypical forms of spinal tuberculosis.

Twenty-three patients with atypical forms of spinal tuberculosis treated between 1975 and 1985, are described. All presented with signs and symptoms of compression of the spinal cord or cauda equina, ranging from paraesthesiae and increasing weakness of extremities to paraplegia and loss of sphincter control. None of them showed visible or palpable spinal deformity nor the typical radiographic appearance of destruction of the intervertebral disc and the two adjoining vertebral bodies. These atypical forms constituted about 12 percent of all the cases of spinal tuberculosis seen (a total of 190 cases); and fell into three well-defined groups: those with the involvement of neural arch only; those with the involvement of a single vertebral body; and, those without bony involvement. The correct surgical approach in these groups was found to be different: spinal cord compression caused by the tuberculous disease of the neural arch was best treated by laminectomy; whereas single vertebral body disease required an anterior or anterolateral approach. Spinal computerized tomography was helpful in defining the extent of disease and planning the surgical approach. Histological confirmation of tuberculosis was obtained in all the cases and acid fast bacilli (A.F.B.) were found in, and cultured from, the biopsy specimens of 18 cases.