Abstract
BACKGROUND: To compare mid-term outcomes of plate cage systems (PC) vs. stand-alone cages (SA) in two-level ACDF for cervical spondylotic myelopathy (CSM) with cervical kyphosis, and to assess the influence of preoperative segmental kyphosis reducibility on sagittal alignment maintenance. METHODS: This retrospective cohort analyzed 130 patients (SA = 64, PC = 66) with ≥24-month follow-up. Radiographic parameters (cervical lordosis [CL], fusion segmental lordosis [FSL], disc wedge, C2 SVA) and clinical outcomes (NDI, VAS, JOA, EQ-5D, dysphagia) were assessed preoperatively, postoperatively, and at final follow-up. Patients were stratified based on preoperative reducibility of segmental kyphosis. RESULTS: Both groups showed comparable clinical improvement (p < 0.05) and fusion rates (93.8% SA vs. 95.4% PC, p = 0.667). SA had shorter operation time (78.0 ± 11.5 vs. 86.6 ± 12.5 min, p < 0.001), less blood loss (193.0 ± 85.6 vs. 256.7 ± 110.3 mL, p < 0.001), and lower dysphagia incidence (12.5% vs. 20.3%, p = 0.014). However, the PC group demonstrated superior maintenance of cervical sagittal alignment in CL (13.6° ± 0.9° vs. 12.3° ± 2.4°, p < 0.001), FSL (13.2° ± 1.2° vs. 11.9° ± 2.9°, p = 0.001), and disc wedge (10.2° ± 1.3° vs. 8.9° ± 2.6°, p < 0.001) at follow-up, particularly in patients with non-reducible kyphosis (p < 0.05). CONCLUSION: SA offers operative efficiency advantages, while PC is more effective in maintaining sagittal alignment, especially in rigid kyphosis. PC is recommended for patients with non-reducible cervical kyphosis.