Anterior cervical discectomy and fusion versus posterior decompression in patients with degenerative cervical myelopathy: a systematic review and meta-analysis

OBJECTIVE The optimal surgical approach for patients with multilevel degenerative cervical myelopathy (DCM) remains unknown. This systematic review and meta-analysis sought to compare anterior cervical discectomy and fusion (ACDF) versus posterior decompression (PD) in patients with DCM spanning ≥ 2 levels without ossification of the posterior longitudinal ligament. METHODS MEDLINE and PubMed were searched from inception to February 22, 2022. The primary outcomes were Neck Disability Index (NDI), SF-36 Physical Component Summary (PCS), modified Japanese Orthopaedic Association (mJOA) scale, visual analog scale (VAS), and EQ-5D scores. Secondary outcomes were operative bleeding, operative duration, hospital length of stay (LOS), postoperative morbidity (including hematoma, surgical site infection [SSI], CSF leakage, dysphagia, dysphonia, C5 palsy, and fusion failure), mortality, readmission, reoperation, and Cobb angle. RESULTS Nineteen studies comprising 8340 patients were included, of whom 4118 (49.4%) and 4222 (50.6%) underwent ACDF and PD, respectively. The mean number of involved spinal levels was comparable between the groups (3.1 vs 3.5, p = 0.15). The mean differences (MDs) of the primary outcomes were the mean of each index in the ACDF group minus that of the PD group. At the 1-year follow-up, the MDs of the NDI (−1.67 [95% CI −3.51 to 0.18], p = 0.08), SF-36 PCS (2.48 [95% CI −0.59 to 5.55], p = 0.11), and VAS (−0.32 [95% CI −0.97 to 0.34], p = 0.35) scores were similar between the groups. While the MDs of the mJOA (0.71 [95% CI 0.27 to 1.16], p = 0.002) and EQ-5D (0.04 [95% CI 0.01 to 0.08], p = 0.02) scores were greater in the ACDF group, the differences were not clinically significant given the minimal clinically important differences (MCIDs) of 2 and 0.05 points, respectively. In the ACDF group, the MDs for operative bleeding (−102.77 ml [95% CI −169.23 to −36.30 ml], p = 0.002) and LOS (−1.42 days [95% CI −2.01 to −0.82 days], p < 0.00001) were lower, the dysphagia OR (11.10 [95% CI 5.43–22.67], p < 0.0001) was higher, and the ORs for SSI (0.43 [95% CI 0.24–0.78], p = 0.006) and C5 palsy (0.32 [95% CI 0.15–0.70], p = 0.004) were lower. The other outcomes were similar between the groups. Overall evidence according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach was moderate. CONCLUSIONS ACDF and PD are similar regarding functional outcomes. ACDF is beneficial in terms of less bleeding, shorter LOS, and lower odds of SSI and C5 palsy, while the procedure carries higher odds of dysphagia. The authors recommend individualized treatment decision-making.