Comparison of efficacy for ankylosing spondylitis kyphosis with preoperative osteotomy designs using the Photoshop software or papercut / splice

Objective: Thoracolumbar kyphotic deformity is a common complication in the late stage of ankylosing spondylitis. The aim of this study was to compare the correction efficacy for ankylosing spondylitis kyphosis using preoperative osteotomy designs of papercut (PC)/splice and Photoshop (PS). Methods: This was a retrospective study of 35 patients with ankylosing spondylitis and thoracolumbar kyphotic deformity that underwent correction osteotomy at the Department of Spinal Surgery, Affiliated Hospital of Yan’an University between May 2009 and November 2014. The preoperative osteotomy design using PC/splice was applied in 17 patients and preoperative osteotomy design using PS was applied in 18 patients. The patients were followed-up for 18-30 months. The postoperative osteotomy angle error and correction efficacy at the last follow-up were compared between the two groups. Results: There were significant differences in the errors between postoperative actual and preoperative planned osteotomy angle of the PS group and PC/splice group (P<0.01). The spinal sagittal global kyphosis and sagittal vertical axis in the PS group were 29.3±11.1° and 3.1±1.6 cm, respectively, while those in the PC/splice group were 38.9±13.1° and 5.7±2.1 cm, respectively (P<0.01). The Oswestry Disability index and Scoliosis Research Society (SRS)-22 questionnaire score in the PS group were significantly higher to those in the PC/splice group (P<0.05). PS was independently associated with improvements in SRS-22 scores (OR=63.0; 95% CI: 1.73-2298.19; P=0.02). Conclusion: Compared with osteotomy design using traditional PC/splice, osteotomy design using the PS software could achieve a smaller osteotomy angle error and a better postoperative spinal balance in the sagittal plane.