Radiological morphology variances of osteotomized vertebra-disc complex following pedicle subtraction osteotomy for ankylosing spondylitis with thoracolumbar kyphosis: the incidence, mechanisms, and prognosis

Radiological morphology variances of OVDC were a high occurrence following PSO in AS, being mainly attributed to inaccurate osteotomy cut and VS. Neighboring disc opening and rotational or translational subluxation were major available remedial mechanisms strengthening the lordosing effect when that of vertebral wedging was impaired and insufficient. The bone fusion and remodeling concerning the subluxated or dislocated osteotomized vertebra was utterly favorable, maintaining the kyphosis correction and preventing instrumentation failure.