ObjectiveTo introduce the application of Photoshop CS16.0 (PS) software in preoperative osteotomy design of ankylosing spondylitis kyphosis (ASK), and to investigate applied values of the preoperative design. MethodsBetween March 2009 and March 2013, 21 cases of ASK were treated through preoperative osteotomy design by using PS software. There were 16 males and 5 females, aged from 23 to 50 years (mean, 34.2 years). The deformity included thoracolumbar kyphosis in 14 cases, thoracic kyphosis in 2 cases, and lumbar kyphosis in 5 cases. The ultimate osteotomy angle of preoperative plans and the location and extent of osteotomy were determined by the osteotomy design, which guided operation procedures of the surgeon. The actual osteotomy angle was obtained by measuring Cobb angle of osteotomy segment before and after operation. The sagittal parameters of spine and pelvis including global kyphosis (GK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), and chin brow-vertical angle (CBVA) were measured at preoperation, at 1 week after operation, and last follow-up. The clinical outcomes were assessed by simplified Chinese Scoliosis Research Society-22 (SRS-22) questionnaire and Oswestry disability index (ODI). ResultsNo complications occurred in the other cases except 1 case of dural tear during operation and 1 case of nerve injury after operation, and primary healing of incision was obtained. All patients were followed up 14 to 45 months (mean, 26.3 months). The SRS-22 and ODI scores at 1 week after operation and last follow-up were significantly improved when compared with preoperative scores (P<0.05), but no significant difference was found between at 1 week and last follow-up (P>0.05). The preoperative planned osteotomy angle and the postoperative actual osteotomy angle were (34.2±10.5)° and (33.7±9.7)° respectively, showing no significant difference (t=0.84, P=0.42). The CBVA, GK, SVA, PT, and LL were significantly improved when compared with the preoperative values (P<0.05), but no significant difference was found between at 1 week and last follow-up (P>0.05). At last follow-up, no failures of internal fixation was found, and bony fusion was obtained. ConclusionThe preoperative osteotomy design by using PS software can precisely recover the spinal sagittal balance and horizontal angle of view, so it can effectively avoid excessive correction and insufficient correction of the deformity and obtain good effectiveness in treating ASK.