Healing Pattern of Thoracolumbar Burst Fracture after Posterior Short-segmental Fixation

Background: Vertebral cavity sometimes occurs after posterior short-segmental fixation for thoracolumbar burst fractures, but the risk factor of its formation is unclear. We aim to investigate their vertebral healing pattern and explore the risk factor of vertebral cavities.Methods: The thoracolumbar burst fractured patient treated with posterior short segmental fixation were followed up for minimal 3 years. Healing patterns were observed and divided into 4 healing types according to the integrity status of the endplates and the morphology of the cavities. The demographic characteristics and clinical outcomes were compared between patients with and without vertebra cavities at the last follow-up.Results: The incidence of vertebral cavities in our cohort was 59.6%. Accordingly, the healing pattern of the vertebra were classified as Complete Healing type or Endplate Cavity type, Spherical Cavity type or Burst Cavity type. The proportion of men, history of smoking, severity of neurological impairment and presence of A4 type fracture were significantly higher in the Vertebral Cavity group than the Intact Vertebra group. Clinical outcomes, including ASIA scales,VAS and ODI scores, were similar between the Intact Vertebra group and the Vertebral Cavity group. Conclusions: Vertebral cavities are commonly seen after posterior short-segmental fixation for thoracolumbar burst fractures. The healing pattern can be divided into four types. The presence of vertebral cavity may be related to gender, smoking history and the severity of the fracture. Most of the vertebral cavities are asymptomatic, but the clinical significance needs further study.