TREATMENT OF DEGENERATIVE SPONDYLOLISTHESIS: COMPARISON BETWEEN CONVENTIONAL ANTERIOR FUSION (SCREW-PLATE) AND RETROPERITONEOSCOPIC CAGE FUSION

Abstract

Purpose of the study: Surgical treatment of degenerative spondylolisthesis generally requires spinal fusion. Arthrodesis can be achieved via an anterior or posterior approach. Over the last ten years, minimally invasive methods have been developed to limit operative trauma secondary to the anterior approach. There have however been few studies comparing outcome after this new technique with classical open surgery. The aim of this work was to compare spinal fusion achieved with a cage implanted retroperitoneoscopically with conventional screw-plate fixation using open lombotomy.

Material and methods: Sixty two patients with degenerative spondylolisthesis (L3-L4, L4-L5, L5-S1) were reviewed: 39 had had conventional spinal fusion (group 1) and 23 had undergone a minimally invasive procedure (group 2). Clinical (Beaujon score) and radiographic assessment was recorded at last follow-up. All patients in group 1 were operated on by the same surgeon via lombotomy (L3-L4 or L4-L5 fusion) or subumbilical laparotomy (L5-S1 fusion). An intersomatic graft was combined with screw-plate fixation in all cases. Patients in group 2 were also operated on by the same surgeon (different from group 1) who used a retroperitoneoscopic approach (L3-L4 or L4-L5 fusion). An intersomatic cage was filled with cancelous bone and screwed into the intersomatic space.

Results: Mean follow-up was four years in group 1 and two years in group 2. Mean Beaujon score improved from 8 to 17 in group 1 and from 9 to 16.5 in group 2. All patients achieved bone healing at last follow-up without secondary displacement or disassembly of the osteosynthesis. There were no neurological complications and no infections of the operative site. One patient in group 2 developed a vascular complication requiring conversion to classical lombotomy. Blood loss was 1100 ml in group 1 and 200 ml in group 2.

Conclusion: Anterior fusion with implantation of an intersomatic cage via retroperitoneoscopic access is a reliable and effective method for the treatment of degenerative spondylolisthesis. It reduced postoperative morbidity but must obviously comply with classical indications for lumbar fusion.