Biomechanical analysis of ponte osteotomy and PSO osteotomy in the treatment of ankylosing spondylitis with thoracolumbar kyphotic deformity

Ponte osteotomy distributes stress across multiple segments, reducing internal fixation load, and is therefore suitable for moderate kyphotic deformities. PSO osteotomy provides superior corrective capability but concentrates stress on distal vertebral segments, making it suitable for severe deformities. These results can guide clinical decisions for individualized surgical selection.