PREDICTION OF THORACOLUMBAR FRACTURE KYPHOSIS PROGRESSION FROM STANDING LATERAL RADIOGRAPHS – A ONE YEAR FOLLOW UP STUDY

Abstract

Study Design/Objectives: A pilot study to predict thoracolumbar kyphosis progression secondary to fracture in non-operatively treated patients.

Summary of Background Data: Progressive saggital plane deformity can cause persistent pain after thoracolumbar vertebral fractures. Little data exists to suggest at what interval after the index injury the patient attains a low risk of developing further angular deformity in non-operatively treated patients.

Methods: Supine and erect radiographs were assessed and the degree of fracture kyphosis was determined using an Oxford Cobbometer. The fracture kyphosis was recorded for each follow up appointment along with time after the fracture. A time/data analysis was performed using the Blyth-Still-Casella exact interval.

Results: This study included 22 patients (13 male, 9 female) with average age 67.2 years (range, 14–87 years). The average length of follow up was 11.5 months (range, 5.3–19.9 months) and the average number of radiographs taken within this period was 4 (range, 2–6). The change in fracture kyphosis was plotted against time following fracture. Based on 15 patients with data extending to 200 days follow up, it was observed that the rate of change in fracture kyphosis between two time points of 100 and 150 days predicted the trend in kyphosis progression until the end of follow up in 14 out of the 15 patients. This observed rate of 14/15 (0.93) has a 95% confidence interval of 0.7 to 0.99 (Blyth-Still-Casella exact interval).

Conclusions: The standing lateral radiograph of patients with conservatively treated thoracolumbar fractures at 3 and 4.5 months post injury can be used to predict fracture kyphosis progression. Using this protocol, patients can be safely discharged earlier from outpatient follow up reducing radiological exposure.