Functional disability after instrumented stabilization in lumbar degenerative spondylolisthesis: a follow-up study

Low back pain (LBP) is a widespread health problem and a major contributor to increasing health costs and lost work days. Different pathologies cause LBP and one of these is lumbar degenerative spondylolisthesis (SPL). There are no generally accepted and standardized methods for assessing the outcome of patients treated for degenerative lumbar SPL. This study aims to assess quality of life after surgery for lumbar degenerative SPL through the adoption of outcome measures. We studied 76 patients treated, for degenerative lumbar SPL, with spinal stabilization, decompression and bilateral dorsolateral fusion, followed up for at least two years. We used the Roland-Morris (RM) scale and the Oswestry Disability Index (ODI) to assess the quality of life of the patients before surgery and at follow up. Each patient was pre-operatively studied through standard and dynamic x-rays, CT scan and MRI of lumbar column. Relationships between clinical, radiological and disability scores, grouped by categories, were tested. The sample comprised 25 males and 51 females. Mean age was 59.6 years (SD 12.2). The mean duration of symptoms (from clinical onset to surgery) was 23.42 months (median 13, range 4-100 months). In about half of the cases, duration of symptoms before surgery was >12 months. At follow up, the fusion rate was 85.5%, and the ODI score was significantly reduced: an improvement of <20 points in 35.7% of patients, and of >20 points in 55.7%. On the RM scale, 59.4% of patients had a reduction >5 points, 13.1% a reduction of 2-4 points, and 27.5% an unchanged or worse score. There was no significant reduction in RM scale and ODI scores in patients with fusion versus pseudoarthrosis. Instrumental pedicle screw fixation and arthorodesis seem to be very effective in improving quality of life, as shown by the reduced disability scores at follow up.