Background and Study Aims Although anterior or posterior surgery for cervical spondylotic myelopathy (CSM) has been extensively studied, the choice of anterior or posterior approach in 4-segment CSM remains poorly studied and controversial. We compared the clinical and radiographic outcomes of 4-segment CSM by posterior laminoplasty (LAMP) and anterior cervical decompression fusion (ACDF) to further explore the merits and demerits of ACDF and LAMP surgery for 4- segment CSM in this study. Materials and Methods Patients with 4-segment CSM who underwent ACDF or LAMP surgery between January 2016 and June 2019 were retrospectively analyzed. We compared the preoperative and postoperative cervical Japanese Orthopedic Association (JOA) score, neck disability index (NDI), neck pain visual analog scale (VAS) score, sagittal vertical axis, cervical lordosis (CL), and range of motion. Results There were 47 and 79 patients in the ACDF group and the LAMP group, respectively. Patients in the ACDF group had a significantly longer surgical time and lower estimated blood loss and length of stay than those in the LAMP group. There was no significant difference in the JOA, NDI, or neck pain VAS scores between the two groups preoperatively, but the NDI and neck pain VAS scores in the ACDF group were significantly lower than those in the LAMP group at final follow-up. The preoperative C2-7 Cobb angle of the ACDF group was significantly lower than the LAMP group but showed no significant difference between the two groups postoperatively. The improvement of C2-7 Cobb angle (∆C2-7 Cobb angle) in ACDF group was significantly higher than that in LAMP group. This indicated that ACDF can improve CL better than LAMP. The linear regression analysis revealed the ∆C2-7 Cobb angle was negatively correlated with the final follow-up neck pain VAS scores and NDI. This indicated that patients with better improvement of CL may have better prognosis. Conclusions Although both ACDF and LAMP surgery are effective for 4-segment CSM, ACDF surgery can better improve CL and neck pain. For patients with poor CL, we suggest ACDF surgery when both approaches are feasible.Thieme. All rights reserved.