RESUMEN
23 cases of spondylolisthesis of the lumbo sacral spine are reported. One case is recurrent after previous operation elsewhere. Dysplastic, ischemic and degenerative spondylolisthesis are the main types of this disorder of the lumbosacral spine. Plain x-ray with dynamic films in the erect position are the gold standard for investigating these cases. Loss of parallelism of surfaces of vertebrae at the olisthesis level indicate pathological motion. Conservative treatment should be tried in every case. The decision for surgical treatment is clinical and rests absolutely on the evaluation of the surgeon of the pain syndrome of the patient and other complaints. The author uses a good quality acrylic to fix the whole lumbosacral spine with short screws inserted in the spines of the lumbar vertebrae. Only laminectomy and medial partial facetectomy are required in cases of neurogenic claudication with stable fixed spondylolisthesis. The results of treatment of spondylolisthesis are far from being satisfactory to say the least. The development of pain control centers to treat low back pain and leg pains attest to the failure of the state of art today to manage this disorder on sound scientific basis. These centers specialize in the management of failed back surgery for this conditions and others of the spine. The cause of biological infirmity of the disc may be part of maldevelopment as in dysplastic type or it is inherent in its microstructure. All other pathological phenomena seen in this disorder are secondary effects