EXTERNAL TRANSPEDICULAR FIXATION-TEST OF THE LUMBAR SPINE CORRELATES WITH THE OUTCOME OF SUBSEQUENT LUMBAR FUSION

External transpedicular fixation was applied to the lower lumbar spine in a prospective study on 42 patients with chronic low back pain comb ined with suspected instability of the lumbar segments; the diagnosis was failed disk surgery, spondylolisthesis, and degenerative disk dise ase. The aim was to realign the involved segments, to restore disk hei ght, and to record changes in pain and performance during the external fixation test. Pain was recorded on a visual analog scale, and perfor mance was assessed using the Oswestry disability score. An independent observer assessed the test and treatment results. Twenty-nine patient s experienced relief of pain and performed better in the fixator; they were subjected to anterior interbody fusion, the external frame being kept as a stabilizing device for an additional four months. Twenty-tw o patients have had follow-up evaluations for two years. One and two y ears after successful lumbar fusion, significantly (p < 0.02) better p ain and performance scores were recorded; the results of lumbar fusion corresponded to the preoperative fixation test. A temporary external fixation test may be a useful procedure in patients considered for sub sequent spondylodesis.