Traditional C3-C7 unilateral open-door laminoplasty (UOLP) often lead to various postoperative complications due to damage of cervical posterior muscles and nuchal ligaments. We aimed to thoroughly evaluate postoperative outcomes of following our modified UOLP versus traditional UOLP in treating multilevel cervical spondylotic myelopathy (MCSM).Seventy-six patients with MCSM who underwent the modified UOLP with C3 laminectomy and C7 upper hemi-laminectomy (40 patients) or traditional C3-C7 UOLP (36 patients) were included. Pre- and postoperative cervical radiological parameters, as well as clinical and surgical outcomes were evaluated.Postoperatively, JOA scores improved significantly in modified UOLP group than traditional UOLP group (P=0.028), while VAS scores and NDI scores improved similarly in both groups. Follow-up scores for JOA, NDI and VAS were not significantly different between two groups. At final follow-up, C2-7 sagittal vertical axis and T1 slope increased in traditional UOLP group and did not change in modified UOLP group and were unchanged in modified UOLP group. The C2-C7 Cobb angle decreased significantly in traditional UOLP group and did not change in modified UOLP group. The modified UOLP group lost less cervical posterior muscles area compared to traditional UOLP group (3.72±3.54%vs6.67±2.81%, P<0.001). The range of motion in modified UOLP group showed significantly greater than traditional UOLP group at final follow-up (P<0.001). Also, modified UOLP group experienced a notable reduction in operative time, blood loss volume, and postoperative hospital stay.We recommend performing our modified UOLP with C3 laminectomy and C7 upper hemi-laminectomy instead of traditional C3-C7 UOLP.Copyright © 2024. Published by Elsevier Inc.