Anterior cervical discectomy vs. hybrid decompression and fusion for Multilevel Cervical Spondylotic Myelopathy: clinical outcomes and sagittal alignment predictors

Objective To compare the clinical outcomes of three-level anterior cervical discectomy and fusion (ACDF) versus anterior cervical hybrid decompression and fusion (ACHDF) in patients with multilevel cervical spondylotic myelopathy (MCSM), and to determine whether preoperative sagittal alignment parameters of the cervical spine can predict postoperative outcomes. Methods This retrospective study included 57 patients with MCSM who underwent either three-level ACDF or ACHDF between January 2017 and January 2020. Patients were stratified into two groups based on the modified Japanese Orthopaedic Association (mJOA) improvement rate at the 2-year follow-up: excellent improvement (> 50%, n = 39) and poor improvement (≤ 50%, n = 18). Surgical outcomes and the prognostic value of preoperative sagittal parameters were analyzed. Results Baseline characteristics were comparable between the surgical groups, except for differences in operative time, intraoperative blood loss, and postoperative changes in sagittal alignment. Binary logistic regression identified preoperative C2-7 sagittal vertical axis (SVA) as the sole independent predictor of poor outcome (P = 0.006, OR = 1.103). Receiver operating characteristic (ROC) curve analysis revealed that a C2-7 SVA greater than 25 mm was associated with a significantly increased risk of poor postoperative prognosis. Conclusion In conclusion, A preoperative C2-7 SVA exceeding 25 mm significantly predicts poor postoperative recovery, regardless of surgical technique, and should be integrated into preoperative planning for MCSM. ACHDF is generally applied to cases with more severe vertebral body osteophyte formation and segmental instability. Furthermore, a preoperative C2-7SVA exceeding 25 mm significantly predicts poor postoperative recovery, irrespective of the surgical approach.Both ACDF and ACHDF demonstrated comparable clinical efficacy in the treatment of MCSM. However, a preoperative C2-7 SVA exceeding 25 mm is a significant risk factor for poor postoperative outcomes and should be carefully considered during preoperative planning.