Assessment of risk factors for the vertebral body kyphotic deformity progression in patients with type A1 injuries of the thoracolumbar junction

Abstract

More than 60% of traumatic injuries of the spine occur in the zone of the thoracolumbar junction (TLJ), and 60–75% of these fractures are of a compression nature. Type A1 injuries are characterized by the least osteo-destructive changes compared to other injuries. Traditionally, they are treated conservatively. A number of studies conducted in the last 10 years, shows a high rate of failure of conservative treatment, as evidenced by the progression of kyphotic deformity of the compressed vertebral body. Most of these publications are devoted to osteoporotic lesions in aged patients, while this aspect has been little studied in patients of working age with normal bone density. Objective: to evaluate the factors influencing the risk of kyphotic deformity progression in patients of working age with type A1 traumatic injuries of the thoracolumbar junction. Materials and methods. The analysis of clinical cases of patients who visited the outpatient department of Romodanov Neurosurgery Institute of National Academy of Medical Sciences of Ukraine in the period from 2019 to 2022 with traumatic damage to the TLJ zone. Forty-seven victims who met the selection criteria were selected. Gender, age, body mass index, level of damage, location of the damaged endplate (caudal or cranial), bone tissue radiodensity, angular kyphotic deformity of the vertebral body, and pain intensity were considered as predictors. Depending on the presence or absence of deformity progression 2 months after the injury, the patients were divided into two clinical groups. The most clinically significant predictors were identified using the LASSO (Least Absolute Shrinkage and Selection Operator) regression method. Results. LASSO screening identified five potential predictors. The final logistic regression model after regularization demonstrated high predictive performance: the area under the ROC curve (AUC) was 0.907, and the predictive accuracy was 85%. When assessing the risk of kyphotic deformity progression in traumatic injuries of type A1 of the TLJ zone, age, bone density, angular kyphotic deformity of the vertebral body, and pain intensity are of the greatest importance, demonstrating a directly proportional relationship. A compressed caudal endplate is also associated with a higher risk of post-traumatic progression of angular kyphosis. The nomogram developed using the mentioned factors makes it possible to quantify the degree of risk when choosing a therapy strategy. Conclusions. The performed analysis made it possible to create a nomogram for predicting the increase in kyphotic deformity of the vertebral body in A1 fractures of TLJ region. The proposed model can be used for a rational assessment of the risk degree when choosing the optimal tactics for treating patients.