Abstract
Standard surgical treatment for infectious spondylitis involves anterior debridement and interbody fusion. However, for patients with high morbidity, this may result in many complications. We propose an alternative technique - posterior-only percutaneous pedicle screw fixation without anterior or posterior debridement ("internal orthosis") - to reduce surgical invasiveness while maintaining clinical efficacy. We retrospectively compare the outcomes between conventional and internal orthosis procedures. This retrospective comparative study included patients who underwent surgery for thoracolumbar infectious spondylitis between 2012 and 2021. Patients were divided into 2 groups according to surgical technique: conventional treatment with anterior debridement and posterior fixation, and posterior-only fixation without any debridement. Clinical outcomes (visual analog scale [VAS] score and success rate), laboratory markers (white blood cell count, erythrocyte sedimentation rate, and C-reactive protein), and radiologic parameters (kyphotic/lordotic angle and bone union) were evaluated during follow-up. A total of 45 patients were included in the study (22 in the conventional group and 23 in the internal orthosis group). The internal orthosis group demonstrated significantly shorter operative time (202 ± 71 minutes vs 376 ± 126 minutes, P < .001) and reduced intraoperative blood loss (267 ± 122 mL vs 646 ± 460 mL, P < .001) compared with the conventional group. Inflammatory markers and VAS score improved significantly over time in both groups. Radiologic analysis showed a transient increase in kyphotic angle in the internal orthosis group at one month, although long-term spinal alignment remained stable in both groups. While the conventional group demonstrated a higher rate of radiologic bone union (86.4% vs 43.5%, P = .003), the internal orthosis group achieved similar clinical success, with rates of 95.5% and 87.0%, respectively (P = .608). No other significant group differences were identified in laboratory or radiologic parameters. "Internal orthosis" can be an alternative treatment option for high-risk patients with infectious spondylitis. Despite a lower rate of radiological fusion, clinical outcomes were comparable, suggesting its potential as a truly minimally invasive strategy in selected cases.