J Korean Orthop Assoc.  2021 Jun;56(3):208-214. 10.4055/jkoa.2021.56.3.208.

Correlation of the Deformation of the Kyphotic Angle with the Fat Infiltration Rate of Multifidus and Erector Spinae in Patients with Acute Osteoporotic Fractures of the Lumbar Spine

• Jun DS
• Baik JM
• Baek SH

• KMID: 2516652
• DOI: http://doi.org/10.4055/jkoa.2021.56.3.208

Abstract

Purpose
Verifying a reliable predictor of the progression of vertebral deformity in patients with acute osteoporotic fractures of the lumbar spine may be useful. A qualitative analysis of the muscle near the spine was performed using magnetic resonance imaging (MRI), and its correlation with a spinal deformity was determined under the hypothesis that the causes of the kyphotic deformity are associated with muscle reduction in the multifidus and erector spinae.
Materials and Methods
The study was performed in a retrospective manner using the electronic medical records of patients who presented to the author’s institution between January 2007 and March 2018, and were diagnosed with an acute lumbar fracture. The fat infiltration rates of the multifidus and erector spinae were measured using MRI taken at the time of injury, and the mean value was defined as the total fat infiltration rate (TFI). Based on lateral radiographs of the lumbar spine at the one-year follow-up, the loss of height of the vertebral body, the kyphotic angle and the wedge angle were measured. The statistical significance was confirmed by calculating the Pearson correlation coefficient.
Results
One hundred twenty-nine patients, of which 30 were male and 99 were female, were examined. The mean age was 71.28 years. The mean T-score was - 3.53±0.79 g/cm² , and the mean fat infiltration was 15.20%±11.99%. TFI was positively correlated with age (R=0.373, p<0.001), compression rate (R=0.369, p<0.001), and Cobb’s angle (R=0.386, p<0.001) after a one year follow-up, but negatively correlated with the BMD score (R= - 0.252, p=0.004). As the fracture progressed to the lower lumbar level, the compression rate (R= - 0191, p=0.030) and wedge angle (R= - 0.428, p<0.001) at the time of injury tended to decrease.
Conclusion
In patients with osteoporotic vertebral fractures, the fat infiltration rate may be an important predictor of conservative treatment. The prognosis of patients with a high-fat infiltration rate should be explained during patient education, and the patients must be monitored closely through short-term outpatient follow-up.

Keyword

osteoporotic spinal compression fracture; sarcopenia; osteoporosis; fat infiltration rate; conservative treatment