[Success factors in posterolateral arthrodesis of the lumbosacral spine].

The authors have performed 180 posterolateral fusions of the lumbar spine for various conditions. A new method of evaluation of the results is proposed using a careful analysis of the pre-operative and post-operative condition of the patient. The overall ratio of fusion was satisfactory and the etiology did not influence the result. The rate of fusion was not improved when screws were inserted into the articular processes. The level and extent of the arthrodesis did not affect the rate of fusion. Both sides should be fused whenever possible. The functional results were better in cases of degenerative spondylolisthesis than in cases of narrowing of the spinal canal without slipping. They were also better when fusion was obtained. Two cases of pure lumbar pain had good results provided that sedentary work could be done by the patient. A preoperative psychiatric examination was useful. The presence of overweight and a long preoperative period of pain were not favourable. In 49 cases, the arthrodesis was made after one or more previous surgical procedures. The results were more satisfactory when the arthrodesis was made without any associated operation on the spinal canal.