Facet Joint Violation by Thoracolumbar Percutaneous Pedicle Screw and Its Effect on Progression of Facet Joint Osteoarthritis

STUDY DESIGN: A retrospective study. PURPOSE: This study aimed to investigate the rate and associated factors of facet violation (FV) in percutaneous pedicle screws (PPS) from the thoracic to the lumbar spine and the effect of FV on facet osteoarthritis (OA) progression. OVERVIEW OF LITERATURE: Some reports claim PPS has a higher FV rate than conventional open surgery. However, previous reports of FV in PPS were limited to the lumbar spine; only a few reports included the thoracic spine. METHODS: The present study includes 1,028 PPS inserted from T4 to S1 in 218 patients. The rate of FV and facet OA progression after FV were assessed using computed tomography (CT) scans conducted postoperatively at 1 week and 6 months or more. To identify factors associated with FV or facet OA progression after FV, a multivariate logistic regression analysis was conducted. To investigate whether FV caused facet OA progression, we compared OA progression between patients with FV and matched controls. RESULTS: FV was observed in 68 (6.6%) of the 1,028 facets, and the thoracic spine was identified as an independent factor associated with FV. OA progression was detected in 48.2% of the cases with FV via CT scans conducted postoperatively at a mean duration of 22.6 months. The time between CT scans was identified as an independent factor for facet OA progression after FV. The rate of OA progression in patients with FV was significantly greater than that of the controls. CONCLUSIONS: FV was observed in 6.6% of the patients, and the thoracic spine was identified as an independent factor associated with FV. OA progression of a violated facet occurs over time. FV is considered a complication leading to facet OA progression.