Retrolisthesis and lumbar disc herniation: a postoperative assessment of outcomes at 8-year follow-up.

BACKGROUND CONTEXT: Lumbar disc herniation and retrolisthesis have been shown to be significant degenerative changes that can be associated with back pain. Current literature has shown evidence that retrolisthesis is associated with similar baseline function in patients with L5-S1 disc herniation, but worse postoperative outcomes 2 years after lumbar discectomy. However, literature comparing long-term postoperative outcomes at 8-year follow-up in patients with L5-S1 disc herniation with retrolisthesis is lacking.

PURPOSE: The purpose of the present study is to compare long-term postoperative outcomes at 8-year follow-up in patients with retrolisthesis and L5-S1 disc herniations to patients with L5-S1 disc herniations without retrolisthesis.

STUDY

DESIGN

Retrospective review of prospectively collected data from the Spine Patients Outcomes Research Trial (SPORT) database.

PATIENT SAMPLE: Sixty-five patients who underwent lumbar discectomy for L5-S1 disc herniations with 8-year follow-up from the SPORT.

OUTCOME MEASURES: Short Form (SF)-36 bodily pain scale, SF-36 physical function scale, Oswestry Disability Index, Sciatica Bothersomeness Index, and reoperation rate.

METHODS

Baseline surgical parameters, length of stay, complication rates, reoperation rates, and outcome measures were recorded in the SPORT database. Follow-up data were collected at 6 weeks, 3 months, 6 months, 1 year, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, and 8 years. Retrolisthesis was defined as posterior subluxation ≥8%. Patients with and without retrolisthesis were compared using a mixed-effects model of longitudinal regression. Outcomes were calculated as time-weighted averages over 8 years. Reoperation rates were compared using the log-rank test based on time to first reoperation.

RESULTS

One hundred-twenty five patients met inclusion criteria for the present study, including 29 patients with retrolisthesis (23.3%) and 96 patients who did not have retrolisthesis (76.7%). The greatest difference in clinical outcome measures was found at 2 years postoperatively. This was the only point at which both the Short Form-36 Bodily Pain scale (SF-36 BP) and PF showed significant differences between the retrolisthesis and nonretrolisthesis group. At 3 years, SF-36 BP was significantly lower in patients with retrolisthesis (39.9 vs. 52, p=.046). At 8-year follow-up, the presence of retrolisthesis in patients undergoing L5-S1 discectomy was not associated with worse outcome measure scores based on the area under the curve analysis for any metric investigated (SF-36 BP 41.4 vs. 47.1, p=.18; SF-36 Physical Function scale 38.9 vs. 45.4, p=.12; Oswestry Disability Index -39.4 vs. -34.8, p=.23; -11.6 vs. -10.4, p=.25) or a difference in reoperation rate (retrolisthesis group 10%, nonretrolisthesis group 17%, p=.41).

CONCLUSIONS

While retrolisthesis can contribute to low back pain and dysfunction in patients undergoing lumbar discectomy for L5-S1 herniated nucleus pulposus in early follow-up, no significant difference was found in postoperative outcomes after 3 years. Additionally, retrolisthesis was not found to be associated with different reoperation rates at 8 years postoperatively.