Background There have been no prospective studies comparing anterior surgery and posterior method in terms of long-term outcomes. The purposes of this study is to clarify whether there is any difference in long-term clinical and radiologic outcomes of anterior decompression with fusion (ADF) and laminoplasty (LAMP) for the treatment of cervical spondylotic myelopathy (CSM). Methods Ninety-five patients were prospectively treated with ADF or LAMP for CSM in our hospital from 1996 through 2003. On alternate years, patients were enrolled to receive ADF (1997, 1999, 2001, and 2003: ADF group, n = 45) or LAMP (1996, 1998, 2000, and 2002: LAMP group, n = 50). We excluded 19 patients who died during follow-up, and 25 who were lost to follow-up. Clinical outcomes were evaluated by the recovery rate of the Japanese Orthopaedic Association (JOA) score between the two groups. Sagittal alignment of the C2–7 lordotic angle and range of motion (ROM) in flexion and extension on plain X-ray were measured. Results Mean age at the time of surgery was 58.3 years in the ADF group and 57.9 years in the LAMP group. Mean preoperative JOA score was 10.0 and 10.5, respectively. Mean recovery rate of the JOA score at 3–5 years postoperatively was significantly higher in the ADF group (p &lt
0.05). Reoperation was required in 1 patient for pseudarthrosis and in 1 patient for recurrence of myelopathy in the ADF group
no patient in the LAMP group underwent a second surgery. There was a significant difference in maintenance of the lordotic angle in the ADF group compared with the LAMP group (p &lt
0.05), but not in ROM. Conclusions Both ADF and LAMP provided similar good outcomes at 10-year time-point whereas ADF could achieve more satisfactory outcomes and better sagittal alignment at the middle-term. However, the incidence of reoperation and complication in the ADF group were higher than those in the LAMP group. Study design A prospective comparative study (not randomized).