Factors associated with long-term deterioration in back pain after surgical treatment for low-grade lumbar spondylolisthesis at 2 and 5 years: an evaluation from the Quality Outcomes Database spondylolisthesis data.

OBJECTIVE

Symptomatic, low-grade spondylolisthesis is usually well treated by surgical intervention. While some patients obtain less than optimal improvement, low-grade spondylolisthesis deteriorates in a few patients. The purpose of this study was to investigate what factors predict deterioration in back pain scores after surgical treatment of low-grade spondylolisthesis.

METHODS

The Quality Outcomes Database (QOD) was queried for patients who underwent single-level surgery for management of grade 1 spondylolisthesis, including decompression with fusion and decompression alone. Patient-reported outcomes (PROs) were collected at baseline and then 3 months, 1 year, 2 years, and 5 years postoperatively, including numeric rating scale (NRS) back and leg pain, Oswestry Disability Index (ODI), and EuroQol-5D scores. Patients were categorized based on NRS back pain scores compared to baseline as ≥ 0 (improved or no worse) versus < 0 (worsened). These two groups were compared with respect to factors that predicted postoperative deterioration in NRS back pain scores.

RESULTS

Of 608 cases enrolled, 369 met inclusion criteria for the 24-month cohort. Three hundred twenty-four patients had improved or stable back pain scores (of whom 79% underwent fusion), while 45 reported worse back pain at 24 months (of whom 49% underwent fusion). In the 60-month cohort (n = 429), 376 had improved or stable back pain scores (of whom 81% underwent fusion), while 53 reported worse back pain (of whom 49% underwent fusion). On multivariate analysis, lower baseline NRS back pain scores were associated with back pain deterioration at both time points. Less ODI improvement at 3 months postoperatively and persistent leg pain at 12 months postoperatively were also associated with ultimate deterioration in back pain scores.

CONCLUSIONS

Most patients (88%) improved after surgery while deterioration was only reported in a few patients (12%). Patients with better back pain scores at baseline were more likely to report deterioration in back pain scores at 2 and 5 years postoperatively. There also appeared to be a trend toward deterioration in those who underwent decompression alone without fusion. These findings highlight the risks of operating on patients with less severe symptoms, as well as the need to improve the understanding of which patients would benefit from fusion. Persistent leg pain and less ODI improvement were also associated with deterioration in back pain scores.