One-stage posterior grade 4 osteotomy and bone graft fusion at pseudarthrosis for the treatment of kyphotic deformity with Andersson lesions in ankylosing spondylitis

Highlights • Show a new approach for the treatment of kyphotic deformity with ALs in AS. • To debride pseudoarthrotic tissue, correct kyphotic deformity and bone graft by one approach. • Avoid the complications of the anterior approach and obtain the advantages of anterior fusion. • Present smaller blood loss and operation time, few complications and good safety. • Provide satisfactory correction for LK and get successful fusion and good clinical outcomes.