Dynamic Stabilization Surgery in Patients with Spinal Stenosis: Long-term Outcomes and the Future.

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The purpose of this study was to analyze the long-term results for patients with lumbar spinal stenosis (LSS) treated with dynamic stabilization (DS) and to consider how we can improve the results.

SUMMARY OF BACKGROUND DATA

Few studies have reported long-term outcomes of DS surgery for LSS with or without spondylolisthesis.

METHODS

A single-center, single-surgeon consecutive series of LSS patients who underwent DS surgery with at least 5 years of follow-up were retrospectively reviewed. Twenty-seven patients were included in the LSS group and 38 patients in the spondylolisthesis group. Patient characteristics, operative data, radiographic parameters, clinical outcomes, and complications were analyzed at baseline and follow-up.

RESULTS

In the LSS group, all radiographic parameters (e.g., disc height, segmental lordosis, segmental range of motion [ROM] at the index level and proximal adjacent level, global lordosis, and global ROM) were maintained well until the last follow-up. In the spondylolisthesis group, global lordosis decreased from 36.5° ± 8.2° to 32.6° ± 6.0° at the last follow-up (P = 0.039), and global ROM decreased from 22.1° ± 6.9° to 18.8° ± 7.1° at the last follow-up (P = 0.012). In both groups, back pain, leg pain, and Oswestry Disability Index scores showed significant and sustained improvements. Screw loosening occurred in three patients (11.1%) in the LSS group and five patients (13.2%) in the spondylolisthesis group. Symptomatic adjacent segment degeneration (ASD) occurred in two patients (7.4%) in the LSS group and three patients (7.9%) in the spondylolisthesis group.

CONCLUSION

Decompression and DS surgery for LSS with or without spondylolisthesis showed favorable long-term surgical outcomes with an acceptable rate of complications and ASD. However, an improved physiological DS system should be developed.Level of Evidence: 4.