Background:

Cervical pseudarthrosis is a postoperative adverse event that has both clinical and financial implications and occurs when a surgically induced fusion fails to establish bone growth connecting the two regions. It may result in significant patient morbidity and continues to be one of the leading causes of pain after surgery.

Methods:

A retrospective, longitudinal cohort study was performed. Patients in IBM® MarketScan® Commercial Claims and Encounters (CCAE) Database, 18-64 years old who underwent elective cervical fusions during the years 2015-2019 were included. Trauma, infection, or neoplasm patients were excluded. Patients were followed for two years from surgical fusion for occurrence of pseudarthrosis. After pseudoarthrosis, subsequent surgery was documented, and cumulative incidence curves, adjusted for patient/procedure characteristics, with 95% confidence intervals (CI) were generated. Risk factors were evaluated with multivariable Cox regression analysis.

Results:

The cohort included 45,584 patients. The one- and two-year incidence (95% CI) of pseudarthrosis was 2.0% (1.9%-2.2%) and 3.3% (3.1%-3.5%), respectively. Factors significantly associated with increased risk of pseudarthrosis were female gender, current/prior substance abuse, prior spinal pain in the cervical/thoracic/lumbar spine, and Elixhauser score of 5+. Factors significantly associated with decreased risk of pseudarthrosis were anterior cervical approach, use of an interbody cage, and 2-3 level anterior instrumentation. The one- and two-year incidence (95% CI) of subsequent surgery in pseudarthrosis patients was 11.7% (9.6%-13.7%) and 13.8% (11.5%-16.2%), respectively.

Conclusion:

Cervical pseudarthrosis and subsequent surgery still occur at a low rate. Surgical factors such as anterior approach, interbody cage use, and anterior instrumentation may reduce pseudarthrosis risk.