DECOMPRESSION AND POSTERIOR DYNAMIC FLEXION-RESTRICTING STABILISATION IN PATIENTS WITH DEGENERATIVE SPONDYLOLISTHESIS – A SAFETY AND EFFICACY STUDY

Background Degenerative spondylolisthesis (DS) with stenosis is now typically treated by decompression and instrumented fusion. This treatment method does produce predictable results at the spondylolisthetic level, but later stenosis will occur commonly at the adjacent level due to the rigidity of the construct. Pedicle screw fusion may also be a significantly invasive procedure for an elderly patient. Aim To evaluate the clinical potential of a new, non-screw based, posterior dynamic flexion-restricting stabilization system (FRSS). Method 17 patients (15f, 2m; mean age 68 (45-78yr)) presenting with leg pain, with or without low back pain, and MR evidence of spinal stenosis with DS were treated by uni- or bilateral laminotomy and FRSS. Microdiscectomy was performed for one patient with a concomitant disc prolapse. The FRSS was placed at L4/5 in 13 patients and at L3/4 in four. Results Follow up data was available for 12 patients at 3 months and 9 patients at 6 months. At 3 months the mean pain scores (VAS) for both back and leg pain (p 10 point) had improved and 82% were satisfied. Three patients had adverse events unrelated to the device or procedure. At 6 months the improvements were maintained in 8 patients. One complained of transient leg neuralgia (78% overall group satisfaction). There was no evidence of vertebral translation on flexion radiography. Mean blood loss at surgery was 220ml (50-1400ml) and instrumentation time 23min (10-54min). Discussions and Conclusion Early data demonstrates good clinical outcomes in patients with DS treated with decompression and FRSS. Further follow up is necessary to evaluate whether stabilization with the FRSS can help to maintain the benefits of decompression over the longer-term. REC: 10/MRE00/9