A prospective study of lumbar spinal movements before and after discectomy using biplanar radiography. Correlation of clinical and radiographic findings.

The significance of alteration of lumbar spinal motion in cases of herniated disc was examined using a three-dimensional x-ray technique (biplanar radiography) before and 3 months after discectomy. Fifteen consecutive cases of disc herniation were studied prospectively. Predictions of clinical examination, myelography, and motion study for the level and site of the lesion were correlated with the operative findings for their accuracy in localization of the lesion. Changes in lumbar spinal motion after surgery were also correlated with the clinical results. The clinical and myelographic predictions were similar to previously published studies. The present study showed that patients with a sequestrated or prolapsed disc lesion (as opposed to bulging disc) had an abnormally large lateral bend or axial rotation during flexion and extension at the level above, which reduced after surgery. Primary lumbar spinal motions (flexion and extension) were generally reduced to half of the normal value and were not significantly altered by surgery. The restriction of lumbar spinal motion was not significantly reflected in the clinical results, which were satisfactory in most cases. Discectomy by fenestration and minimal resection of the lamina did not produce instability.