National Complication Rates and Disposition After Posterior Lumbar Fusion for Acquired Spondylolisthesis

STUDY DESIGN: Database study using Nationwide Inpatient Sample (NIS) administrative data from 1993 to 2002. OBJECTIVE: To determine rates of in-hospital complications and complex disposition for patients undergoing posterior lumbar fusion for degenerative spondylolisthesis, and the association of demographic factors. SUMMARY OF BACKGROUND DATA: Spondylolisthesis affects primarily elderly populations. Recent data suggests a benefit of surgical treatment for acquired lumbar spondylolisthesis. However, the risks of these procedures, and the impact of patient demographics on risk, have not been nationally quantified. METHODS: Data from 66,601 patients in the NIS (1993-2002) with diagnostic and procedure codes specifying posterior lumbar fusion for acquired spondylolisthesis were included. Patients were grouped by age, sex, race, number of comorbidities, hospital size, and time period of procedure. Multivariate analysis correlated patient and hospital characteristics with complex disposition and complications. RESULTS: Mortality rate was 0.15%. Eleven percent of patients had one or more in-hospital complications; overall complication rate was 13 per 100 operations. Hematoma/seroma (5.4 per 100) was the most common complication, followed by pulmonary (2.6), renal (1.8), and cardiac (1.2) complications. Infection and neurologic injury occurred in <1% of patients. Older patients and those with a number of comorbidities had greater rates of in-hospital complication and complex disposition. Compared to those aged 45 to 64, patients aged 65 to 84 were almost 70% more likely to have complications (OR: 1.67) and 5 times as likely to have complex disposition (OR: 5.84). Having 3 or greater comorbidities, compared to no comorbidities, was also associated with increased risk of complication (OR: 1.6) and complex disposition (OR: 2.3). CONCLUSION: Posterior lumbar fusion for acquired lumbar spondylolisthesis is safe. However, age and comorbidity independently increase in-hospital complications and complex disposition. These data may improve national estimates of surgical risk, patient selection, informed consent, and cost-efficacy analysis for posterior lumbar fusion operations for acquired spondylolisthesis.