Analysis of Factors Affecting Postoperative Loss of Reduction in Unstable Thoracolumbar Fractures

ABSTRACT

STUDY DESIGN: Retrospective analysis OBJECTIVES: Loss of fracture reduction after posterior surgery to treat unstable thoracolumbar fractures can cause several complications. We analyzed the factors influencing postoperative loss of reduction. SUMMARY OF LITERATURE REVIEW Controversy exists about the factors causing postoperative loss of reduction in thoracolumbar fractures during the follow-up period. MATERIALS AND METHODS: We analyzed the records of 59 patients who underwent posterior surgery for thoracolumbar unstable fractures and had completed a minimum follow-up of 1 year. Postoperative loss of reduction was defined as 30% or more loss of vertebral body height or 15° or more progression of the kyphotic angle at the 1-year follow-up compared to immediately after surgery. The associations between the patients??gender, age, level of fracture, injury of the posterior column, initial loss of fractured vertebral body height, load-sharing score, Thoraco-Lumbar Injury Classification and Severity score, number of fixed segments, type of pedicle screws, degree of postoperative reduction, degree of postoperative corrected kyphotic angle, changes in the insertion angle of the most proximal and the most distal pedicle screws, decreases in the upper and lower disc height of the fractured vertebral body, and postoperative loss of reduction were analyzed. RESULTS: Thirteen patients (22.0%) had postoperative loss of reduction. Age at the time of the operation (p=0.034), initial loss of fractured vertebral body height (p=0.042), and changes in the insertion angles of the most distal pedicle screws (p=0.021) were significantly associated with postoperative loss of reduction. However, the other factors did not show a significant relationship. CONCLUSIONS: In patients who underwent posterior surgery for unstable thoracolumbar fractures, the frequency of loss of reduction was high in patients more than 45 years old at the time of the operation, with a 50% or more loss of the initial fractured vertebral body height, and with changes of 5° or more in the insertion angles of the most distal pedicle screws.