Surgical Treatment Of L4/L5 Degenerative Spondylolisthesis - An Outcome Analysis**

In an effort to evaluate the effectiveness of contemporary treatment for L4/L5 degenerative spondylolisthesis, a prospective outcomes study was performed on 50 patients using the SF–36 outcome instrument. All patients were diagnosed with a degenerative L4/L5 spondylolisthesis and had failed non–operative therapy. They were treated with posterior lumbar decompression and posterolateral fusion with autogenous iliac crest bone graft by one single surgeon at one institution. Of these patients, 49 underwent spinal instrumentation with pedicular screw and rod devices. The average follow–up was 3.8 years with a 2–year minimum follow–up from surgery (range 2.3–6.0 yrs). Average age at surgery was 66 years.

SF–36 outcomes questionnaires were administered pre–operatively, and at 3, 6, 12, and 24 months post–operatively and yearly thereafter. Statistically significant improvements were found comparing the pre– operative and post–operative SF–36 scores for bodily pain, physical functioning, role limitations–physical and the physical component score. This score improvement indicates patient improvement after the surgery. The paired t–test revealed p–values of less than 0.05 for each of the above groups. Estimated mean differences and 95% confidence intervals were also calculated and support the conclusions.

There were no deaths or neurological complications post–operatively. 5 patients required re–operation, 1 for pseudarthrosis, 1 for deep infection, 2 for spinal stenosis above the fused segment at 3–4 years after fusion, and 1 for spondylolisthesis above the fused segment. The average blood loss was 392cc. The average number of levels fused was 2. This study demonstrates the efficacy of lumbar decompression and fusion for degenerative L4/L5 spondylolisthesis by use of a well–accepted outcomes instrument. To the authors' knowledge, this represents the largest prospective study to date with this diagnosis and the SF–36 outcome instrument. It enables us to compare results across specialty line and justify our approach to this common spinal deformity.

** The FDA has not cleared a drug and/or medical device for the use described in this presentation. (i.e., the drug or medical device is being discussed in an “off–label" use).