Survival Analysis of Posterior Short Fusion in Thoracolumbar Fracture: Significance of Load-Sharing Score and Bone Mineral Density-Changseop / 대한척추외과학회지

ABSTRACT

STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate the fixation survival rate and the radiologic prognostic factors of posterior short fusion in thoracolumbar fracture. SUMMARY OF BACKGROUND DATA Posterior short fusion has the advantage of saving motion segments in spite of high fixation failure rate. The high load-sharing score is well known as a cause of fixation failure, but the effect of osteopenia is not evaluated. MATERIALS AND METHODS: Authors evaluated 27 patients treated surgically with posterior short fusion using pedicle screws as thoracolumbar fractures from 1995 to 1999. The median follow-up was 20.5 months (6-54). The survivorship using Kaplan-Meier method and the radiologic prognostic factors were evaluated. RESULTS: The sagittal index was preoperatively 16.7 dgree (+/-7.9 SD), immediate postoperatively 6.9 dgree (+/-4.6), and at last follow-up 10.6 dgree (+/-6.9). The fixation failures were detected in 4 patients, and the failure time was ranged from 6 months to 11(median 7.5). The overall survival rate was 82.3% at the last follow-up. The significant prognostic variables were load-sharing score, Jikei grade, compression percent and age in uni-variate analysis, but the load-sharing score and Jikei grade were significant prog-nostic factors in multivariate analysis. CONCLUSIONS: In decision to perform posterior short fusion, the load-sharing score and evidence of osteopenia should be consid-ered as a prognostic factors to avoid fixation failure in thoracolumbar fracture.