[The internal fixator in nontraumatic indications in spinal surgery].

This series includes 59 consecutive patients, 51 of whom had a minimum follow up of 2 years. The diagnosis was mechanical instability in 39, deformity in 11, and infection or tumor in 9 patients. The overall clinical results of the total group were good or fair in 88% of the patients. Pseudarthrosis occurred twice. We had on postoperative infection, one persistent and two reversible neurological complications. We found 13 broken screws and one rod breakage which had no clinical relevance. None of these asymptomatic complications required revision. The internal fixator has a great potential of correction in scoliotic and kyphotic deformities of the spine. It has not been shown to have the same potential in spondylolisthesis. A combined anterior and posterior stabilisation is needed in severe spondylolisthesis. We have found the internal fixator to provide satisfactory stability to allow fusion and good clinical results with a low rate of relevant complications.