Study finds no relationship between lumbar fusion costs and effects

However, researchers noted a reduced surgical effect in smokers and in cases of multilevel fusion.

Issue: Issue 6 2005

Denmark flag While more expensive medical treatments might often seem to produce better results, a group of Danish investigators found otherwise when they studied the costs and treatment effects of lumbar spine fusions.

According to Rikke Søgaard, MPH, “To our surprise we found no correlation between costs and treatment effects.”

Søgaard and her co-investigators at the Spine Unit, Orthopaedic Research Lab at the University Hospital of Aarhus, Denmark, prospectively studied the relationship between the costs and effects of lumbar spine surgery in 136 consecutive patients with severe chronic low back pain (CLBP). “We hypothesized that costs are positively correlated with effects and that the determinants for cost effectiveness are the same determinants as those found to predict the clinical outcome,” Søgaard said.

She presented these results at the 2005 Annual Congress of the Spine Society of Europe (EuroSpine 2005). Patients underwent lumbar fusions in 2001 and 2002 and had a minimum of two years’ follow-up.

Investigators included in their cost analysis all activities related to the treatment from the patients’ standpoint, as well as the hospitals’, which included diagnosis, admission, surgery, rehabilitation and all follow-up procedures. They determined the treatment effect by administering the Dallas Pain Questionnaire to patients preoperatively and at two years postop.

Regression analysis

The researchers did linear regression analysis and then converted any two-dimensional cost factors into one-dimensional parameters to more directly compare the costs of the surgeries. They also identified any factors deemed determinants of cost and effect using multiple linear regression.

EuroSpine 2005 [icon] Not only did costs not correlate with treatment (R=.05), “We found that smoking helped to significantly reduce the net benefit or shift decision-makers’ willingness to pay the above-4000 euros [for smokers]. And, this was also the case for the multilevel fusion compared to the single-level fusion, which was not surprising that it significantly reduced the net benefit,” Søgaard said.

Circumferential fusion also seemed to increase costs compared to posterolateral uninstrumented fusion. But, interestingly, they found that costs were not significantly greater for instrumented vs. uninstrumented posterolateral fusions.

Other factors that they found correlated to a high cost of treatment included advanced education, unemployment and retirement, and how greatly the CLBP affected the patient’s social interactions.

Treatment costs were not affected by age, gender or diagnosis.

During her presentation, Søgaard explained the impact some of these findings may have on spine care and what future research in this area might involve. “Of course, the effects investigated are changed in status over time and not solely due to the fusion regimen,” she noted.

“Although we did our best effort to multivariately adjust for the missing randomization, these findings may suffer, compounded by indication.” Ultimately, those clinical determinants used for selecting patients for lumbar spine fusion might need to be altered, since the costs/outcomes used in the Danish study did not correlate, based on the determinants they used, she said.

For more information:
Søgaard R, Christensen FB, Christiansen T, Bünger C. Costs and effects in lumbar spinal fusion: Cohort study with a 2-year follow-up in 136 consecutive patients. #57. Presented at EuroSpine 2005. Sept. 21-24, 2005. Barcelona.