Operative strategy for different types of thoracolumbar stress fractures in ankylosing spondylitis

Study Design: There are no accurate guidelines on the operative treatment of ankylosing spondylitis (AS)-related thoracolumbar stress fractures. For this reason, we categorized such bone fractures into 2 types: vertebral body type and intervertebral space type, according to the damage mechanism, cross-section spot, and iconography, and devised a targeted surgical plan based on the characteristics of each fracture type. Objective: To investigate the types and surgical treatment of thoracolumbar stress fractures in AS. Summary of Background Data: Thoracolumbar stress fractures are complications of AS. The patients with AS have a higher fracture risk that is approximately 3.5 times than the healthy. As the mechanism of injury, clinical manifestations, imaging characteristics, and principles of treatment of these fractures differ from those of general spinal fractures, the surgical approach is different from that of AS kyphosis orthopedic surgery. In this study, we summarize the clinical data of 11 AS patients with thoracolumbar fractures and discuss the clinical efficacy of the surgical approach based on the mechanism of injury and radiographic features. Methods: We reviewed the data of 11 patients who underwent surgery for AS-related thoracolumbar stress fractures. Five patients with vertebral body-type fractures underwent vertebral wedge osteotomy through the pedicle and posterior internal fixation, whereas 6 patients with intervertebral space-type fractures underwent anterior spinal decompression with strut grafting and posterior internal fixation. Results: The follow-up period was 2-4 years. After surgery, all kyphosis deformities were corrected, low back pain was relieved immediately, and scores on the visual analog scale improved by >70%. At the final follow-up, kyphosis correction had no significant loss. In the radiographic images, neither nonunion signs of pseudarthrosis plane nor neurologic or infectious complications were observed. Conclusions: Choosing an anterior or posterior surgical approach based on the type of AS-related thoracolumbar stress fracture can enhance the stability of the fracture, effectively restore the neurocanal volume and spinal column's axis of stress, reduce the complications of spinal cord damage, and produce the desired clinical curative effect.