Reoperation Rates Following Instrumented Lumbar Spine Fusion.

STUDY DESIGN: A prospective cohort study.

OBJECTIVE: This study evaluated the cumulative reoperation rate and indications for reoperation following instrumented lumbar spine fusion (LSF).

SUMMARY OF BACKGROUND DATA: LSF reduces disability and improves health-related quality of life for patients with several spinal disorders. The rate of instrumented LSF has drastically increased over the last few decades. The increased incidence of LSF, however, has led to increased reoperation rates.

METHODS: The data are based on the prospective LSF database of Tampere University Hospital that includes all elective indications for LSF surgery. A total of 433 consecutive patients (64% women, mean age 62 years) who underwent LSF in Tampere University Hospital between 2008 and 2011 were evaluated and indications for reoperations were rechecked from patient records and radiographs. The most common diagnosis for the primary surgery was degenerative spondylolisthesis and the mean follow-up time was 3.9 years. The cumulative incidence of reoperations and the "time to event" survival rate was calculated by Kaplan-Meier analysis.

RESULTS: By the end of 2013, 81 patients had undergone at least one reoperation. The cumulative reoperation rate at 2 years was 12.5% (95% confidence interval: 95% CI: 9.7-16.0) and at 4 years was 19.3% (95% CI: 15.6-23.8). The most common pathology leading to reoperation was adjacent segment pathology with a cumulative reoperation rate of 8.7% (95% CI: 6.1-12.5) at 4 years. The corresponding rates for early and late instrumentation failure were 4.4% (95% CI: 2.7-7.0) and 2.9% (95% CI: 1.9-7.1), respectively, and for acute complications, 2.5% (95% CI: 1.4-4.5).

CONCLUSION: Although previous studies reported that early results of spinal fusion are promising, one in five patients required reoperation within 4 years after surgery. Patients and surgeons should be aware of the reoperation rates when planning fusion surgery.

LEVEL OF EVIDENCE: 4.