Study Design. Retrospective population-based cohort study.
Objective. To evaluate the influence of lumbar intervertebral fusion devices on clinical and disability outcomes among Washington State compensated workers with chronic back pain.
Summary of Background Data. The efficacy of lumbar fusion for chronic low back pain remains controversial. Recent randomized controlled trials have shown results of fusion to be equivalent to those of structured exercise and cognitive intervention. Lumbar fusion rates, however, continue to increase nationally, fueled, in part, by introduction of new fusion devices, including intervertebral cages in 1996. It is not known whether these newer devices have improved outcomes, and particularly in compensated workers.
Methods. In this population-based retrospective cohort study, we identified Washington State injured workers who underwent lumbar fusion between 1994 and 2001 from Washington State Workers’ Compensation system administrative database. All the data for this study were obtained from either the claims or medical bill payment databases. Multiple logistic regression analyses were used to examine the association between the surgical technique (interbody cages and/or instrumentation) and the risk of disability, reoperation, and complications following lumbar fusion.
Results. Among the 1,950 eligible subjects, fusions with cages increased from 3.6% in 1996 to 58.1% in 2001. Overall disability rate at 2 years after fusion was 63.9%, reoperation rate 22.1%, and rate for other complications 11.8%. Use of cages or instrumentation was associated with increased complication risk compared with bone-only fusions without improving disability or reoperation rates. Legal, work-related, and psychologic factors predicted worse disability. Discography and multilevel fusions predicted greater reoperation risk. Degenerative disc disease and concurrent decompression procedures predicted lower reoperation risk.
Conclusions. Use of intervertebral fusion devices rose rapidly after their introduction in 1996. This increased use was associated with an increased complication risk without improving disability or reoperation rates.
Large population-based cohort among compensated workers is presented to examine lumbar fusion clinical and disability outcomes as functions of the surgical technique (cages and/or instrumentation). Use of cages or instrumentation was associated with more complications than bone-only fusions without improving the disability or reoperation rates.
From the *Occupational Epidemiology and Health Outcomes Program, University of Washington, School of Public Health and Community Medicine, Seattle, WA; †Occupational Epidemiology and Health Outcomes Program, Department of Environmental and Occupational Health Sciences, University of Washington, School of Public Health and Community Medicine, Seattle, WA, and Washington State Department of Labor and Industries, Olympia, WA; ‡Departments of Orthopedic Surgery and Neurological Surgery, University of Washington, School of Medicine, Seattle, WA; §Department of Health Services, University of Washington, School of Public Health and Community Medicine, Seattle, WA; and ¶Occupational Epidemiology and Health Outcomes Program, Department of Environmental and Occupational Health Sciences, University of Washington, School of Public Health and Community Medicine, Seattle, WA.
Acknowledgment date: February 13, 2006. First revision date: May 14, 2006. Acceptance date: May 15, 2006.
Supported by the Accident and Medical Aid Funds of the State of Washington, Department of Labor and Industries. These research monies are targeted toward reducing the incidence and disability related to occupational injuries and illnesses.
The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication.
State Government funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Sham Maghout-Juratli, MD, MPH, Occupational Epidemiology and Health Outcomes Program, University of Washington, School of Public Health and Community Medicine, 1914 N. 34th St., Suite 101, Seattle, WA 98103-9058; E-mail: firstname.lastname@example.org