Degenerative spondylolisthesis with an intact neural arch: a review of 60 cases with an analysis of clinical findings and the development of surgical management.

The treatment over the past 12 years of 60 patients with degenerative spondylolisthesis with an intact neural arch is reviewed. The patients averaged 65 years of age, with women outnumbering men by a ratio of 2:1. Symptoms in the lower extremities had been present for 3 months to 10 years, although varying back pain had existed for longer periods. Two-thirds showed signs of motor dysfunction. Sensory alterations and a positive Las ègue's sign could be demonstrated in only one-half of the patients studied. Four of 5 patients developed intermittent neurogenic claudication, with varying evidence of painful radiculopathy. The marked disability caused by claudication contrasted sharply with the lesser neurological changes, and these patients required early surgical decompression. Diagnostic studies included electromyography, plain x-ray films, tomography, computed tomographic scanning, and myelography. The latter outlined a relative stenosis caused by olisthesis as well as arthrotic and spondylotic changes that determined the extent of decompressive operation required. The L-4, L-5 interspace was involved in 56 patients, L-3, L-4 was involved in 2, and L-5, S-1 was involved in 2. The ideal operation with L-4, L-5 olisthesis included complete laminectomy of L-4 and L-5 with unroofing of the lateral recesses and foraminotomy. This more extensive procedure was justified because of the failures encountered in previous patients in whom inadequate decompression had been performed. Among failures, obesity, diabetes, hyperlordosis, and extensive long-standing dysfunction were prominent. The relief of symptoms of intermittent neurogenic claudication was the most gratifying response observed. There was no unusual morbidity.