[Clinical efficacy of O-arm navigation-assisted fully visualized precision osteotomy in the treatment of thoracolumbar kyphosis deformity in ankylosing spondylitis].

Objective: To investigate the mid-term clinical efficacy of O-arm navigation system-assisted fully visualized precision osteotomy in the treatment of thoracolumbar kyphosis deformity in patients with ankylosing spondylitis (AS). Methods: A retrospective cohort study was conducted to analyze the clinical data of 37 patients with AS-related thoracolumbar kyphotic deformity who were admitted to the Department of Spine and Spinal Cord Surgery, Henan Provincial People's Hospital, from January 2019 to December 2023. According to the surgical modality, the patients were divided into the navigation group (n=19, treated with O-arm navigation-assisted surgery) and the conventional group (n=18, treated with two-dimensional C-arm fluoroscopy). Operative time, intraoperative blood loss, clinically acceptable screw placement accuracy (Gertzbein-Robbins grades A+B), osteotomy time per segment, achievement rate of preoperative planning, osteotomy fusion rate, radiographic parameters [global kyphosis (GK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI)], and 36-Item Short Form Health Survey (SF-36) scores were compared between the two groups. Results: Among the 37 patients, 31 were male and 6 were female, with an age of (30.6±5.1) years. The follow-up duration was (24.6±5.8) months in the navigation group and (23.8±6.2) (range: 12-35) months in the conventional group; the age was (30.2±4.6) (range: 20.0-37.8) years in the navigation group and (31.1±5.7) (range: 23.4-47.8) years in the conventional group; and preoperative GK was (72.8°±8.1°) (range: 66°-85°) in the navigation group and (72.1°±8.9°) (range: 65°-88°) in the conventional group. Compared with the conventional group, the navigation group had significantly shorter operative time [(228.4±28.1) vs (295.6±35.4) min, P<0.001], less intraoperative blood loss [(910±164) ml vs (1 354±235) ml, P<0.001], and shorter osteotomy time per segment [(47.3±5.8) vs (65.2±9.1) min, P<0.001]. The clinically acceptable screw placement accuracy(Gertzbein-Robbins grades A+B) was higher in the navigation group than in the conventional group [98.5% (317/322) vs 85.2% (259/304), P<0.001], and the achievement rate of preoperative planning was also higher [(95.2±2.8)% vs (80.5±6.1)%, P<0.001]. At the final follow-up, osteotomy-site bony fusion was achieved in all 19 patients in the navigation group and in 17 patients in the conventional group, with no significant difference in osteotomy fusion rate between the two groups (19/19 vs 17/18, P=0.486). At 2 weeks postoperatively and at the final follow-up, GK, LL, SVA, PT, and SS have all improved in both groups compared with the preoperative values (all P<0.001), and the improvements in these radiographic parameters were superior in the navigation group (all P<0.05). At the final follow-up, all SF-36 domain scores improved in both groups compared with the preoperative scores (all P<0.05), and the navigation group had higher bodily pain and social functioning scores than the conventional group (all P<0.05). Conclusions: O-arm navigation system-assisted fully visualized precision osteotomy can improve surgical accuracy and osteotomy efficiency in the treatment of thoracolumbar kyphotic deformity in AS patients, improve sagittal spinal balance, achieve better radiographic correction, and provide superior bodily pain and social functioning scores at the final follow-up.