Fig. 4From: Comparison of smith-petersen osteotomy, pedicular subtraction osteotomy, and poly-segmental wedge osteotomy in treating rigid thoracolumbar kyphotic deformity in ankylosing spondylitis a systematic review and meta-analysisComparison of blood loss; CI, confidence interval. Information: Both SPO and PWO had fewer blood loss than SPOBack to article page