DEGENERATIVE LUMBAR SPINAL STENOSIS - DECOMPRESSION WITH AND WITHOUT ARTHRODESIS

We prospectively evaluated the results of decompression of the spine, with and without arthrodesis, for the treatment of lumbar spinal stenosis without instability in forty-five patients (twenty-one men and twenty-four women) who had been managed between November 1989 and November 1990. The average age at the time of the operation was sixty-seven years (range, forty-eight to eighty-seven years). The patients were randomly assigned to one of three treatment groups (fifteen patients in each group) according to when they were admitted to the hospital. Group I was treated with decompression with laminotomy and medial facetectomy; Group II, with decompression and arthrodesis of the most stenotic segment; and Group III, with decompression and arthrodesis of all of the decompressed vertebral segments. All of the operations were performed by the same surgeon. The average duration of follow-up was twenty-eight months (range, twenty-four to thirty-two months). All three groups had a significant improvement in the distance that the patients were able to walk at the time of the latest follow-up examination compared with before the operation (p < 0.001 for Group I, p < 0.002 for Group II, and p < 0.005 for Group III). With the numbers available, there were no significant differences in the results among the three groups with regard to the relief of pain (p = 0.25 for Group I compared with Group II, p = 0.36 for Group II compared with Group III, and p = 0.92 for Group I compared with Group III). We therefore believe that, in the absence of segmental instability, arthrodesis is not necessary after decompression of the lumbar spine in patients who have degenerative lumbar spinal stenosis, provided that the stabilizing posterior elements of the spine are preserved during the operation.