Results of degenerative spondylolisthesis treated with posterior decompression alone via a new surgical approach

Object. The purpose of this study was to assess radiologically demonstrated results and clinical outcomes in patients with degenerative spondylolisthe sis who underwent posterior decompressive surgery via a new (unilateral) ap proach. This approach allows surgeons to perform central and bilateral deco mpression while only stripping the muscles unilaterally, thus preserving th e posterior osteoligamentous complexes. Methods. The authors evaluated 51 consecutive patients in whom surgery was performed between 1987 and 1996. The mean follow-up period was 4.7 years. T here was no statistically significant difference between the pre- and post operative measurements in percentage of vertebral slippage. Postoperative d ynamic angulation statistically decreased compared with its preoperative va lue (p < 0.05). Improvement of an average of 67% was shown on the Japanese Orthopaedic Association scale, and in 78% of these patients, good to excell ent results were demonstrated. Secondary fusion was required in only three patients (5.9%). Conclusions. This new surgical technique offers a potential alternative for the treatment of degenerative spondylolisthesis in a minimally invasive ma nner, avoiding the risk of causing or aggravating postoperative spinal inst ability.