Fig. 2From: Evaluation of preoperative calculation methods of osteotomy size in ankylosing spondylitis with thoracolumbar or lumbar kyphosisSchematic diagrams demonstrating for the calculation methods of various methods. a FBI method, the osteotomy angle \(\alpha =\) C7TA \(+\) FOA \(+\) CTPA; b SFA method, the osteotomy angle \(\beta =\) SFA \(+\) ITK \(+10\); c HP-HA method; d CAM-HA method; e Surgimap methodBack to article page