Geographic variation in the surgical management of lumbar spondylolisthesis: characterizing practice patterns and outcomes.

BACKGROUND CONTEXT: The role of arthrodesis in the surgical management of lumbar spondylolisthesis remains controversial. We hypothesized that practice patterns and outcomes for this patient population may vary widely.

PURPOSE: This study aimed to characterize geographic variation in surgical practices and outcomes for patients with lumbar spondylolisthesis.

STUDY DESIGN/

SETTING

A retrospective analysis on a national longitudinal database between 2007 and 2014 was carried out.

METHODS

We calculated arthrodesis rates, inpatient and long-term costs, and key quality indicators (eg, reoperation rates). Using linear and logistic regression models, we then calculated expected quality indicator values, adjusting for patient-level demographic factors, and compared these values with the observed values, to assess quality variation apart from differences in patient populations.

RESULTS

We identified a cohort of 67,077 patients (60.7% female, mean age of 59.8 years (standard deviation, 12.0) with lumbar spondylolisthesis who received either laminectomy or laminectomy with arthrodesis. The majority of patients received arthrodesis (91.8%). Actual rates of arthrodesis varied from 97.5% in South Dakota to 81.5% in Oregon. Geography remained a significant predictor of arthrodesis even after adjusting for demographic factors (p<.001). Marked geographic variation was also observed in initial costs ($32,485 in Alabama to $78,433 in Colorado), 2-year postoperative costs ($15,612 in Arkansas to $34,096 in New Jersey), length of hospital stay (2.6 days in Arkansas to 4.5 in Washington, D.C.), 30-day complication rates (9.5% in South Dakota to 22.4% in Maryland), 30-day readmission rates (2.5% in South Dakota to 13.6% in Connecticut), and reoperation rates (1.8% in Maine to 12.7% in Alabama).

CONCLUSIONS

There is marked geographic variation in the rates of arthrodesis in treatment of spondylolisthesis within the United States. This variation remains pronounced after accounting for patient-level demographic differences. Costs of surgery and quality outcomes also vary widely. Further study is necessary to understand the drivers of this variation.