Lumbar spinal stenosis: comparison of surgical practice variation and clinical outcome in three national spine registries

BACKGROUND: Decompression surgery for lumbar spinal stenosis (LSS) is the most common spinal procedure in the elderly. To avoid persisting low back pain, adding arthrodesis has been recommended, especially if there is a coexisting degenerative spondylolisthesis. However, this strategy remains controversial, resulting in practice-based variation.

PURPOSE: To evaluate in a pragmatic study if surgical selection criteria and variation in use of arthrodesis in three Scandinavian countries can be linked to variation in treatment effectiveness.

STUDY DESIGN: An observational study based on a combined cohort from the national spine registries of Norway, Sweden, and Denmark.

PATIENT SAMPLE: Patients aged 50 and higher operated 2011-2013 for LSS were included.

OUTCOME MEASURES: Patient-reported outcome measures (PROMs) Oswestry disability index (ODI) (primary outcome), numeric rating scale (NRS) for leg pain and back pain, and health-related quality of life (EQ-5D). Analysis included case-mix adjustment. In addition, we report differences in hospital stay.

METHODS: Analyses of baseline data were done by analysis of variance (ANOVA), Chi-square, or logistic regression tests. The comparisons of the mean changes of PROMs at one-year follow-up between the countries were done by ANOVA (crude) and analyses of covariance (ANCOVA, case mix adjustment). There are no conflicts of interest. Funding was received from the Danish Society of Spinal Surgery ($5,925), the Northern Norway Regional Health Authority ($5,925) and from Swedish Association of Local Authorities and Regions ($11,885). The sponsor had no role in the acquisition of data, analysis, or preparation of the manuscript.

RESULTS: Out of 14,223 included patients, 10,890 (77%) responded at one-year follow-up. Apart from fewer smokers in Sweden and higher comorbidity rate in Norway, baseline characteristics were similar. The rate of additional fusion surgery (patients without, with spondylolisthesis) was: Norway 11% (4%, 47%), Sweden 21% (9%, 56%) and Denmark 28% (15%, 88%). At one-year follow-up the mean improvement for ODI (95%CI) was: Norway 18 (17 to 18), Sweden 17 (17 to 18), and Denmark 18 (17 to 19). Patients operated with arthrodesis had prolonged hospital stay.

CONCLUSIONS: Real life data from three national spine registers showed similar indications for decompression surgery, but significant differences in the use of concomitant arthrodesis in Scandinavia. Additional arthrodesis was not associated with better treatment effectiveness.