Is the improvement of cervical alignment really essential after three-level anterior cervical discectomy and fusion? A minimal 5-year follow-up

Abstract

Purpose: To identify the importance of sagittal alignment with self-locked stand-alone cage (SSC) and anterior cage-with-plate (ACP) system after 3-level anterior cervical discectomy and fusion (ACDF) on cervical spondylotic myelopathy (CSM) after minimal 5-year follow-up.Methods: 38 patients with SSC system (SSC group) and 26 with ACP system (ACP group) from February 2007 to September 2013 were enrolled. Cervical alignment were C2-7 lordosis (CL), operated-segment CL (OPCL), upper and lower adjacent-segment CL (UCL and LCL) at preoperation (POP), immediate postoperation (IPO) and final follow-up (FFU). Clinical outcomes contained the neck disability index (NDI), the Japanese Orthopaedic Association (JOA) score and adjacent segment degeneration (ASD). Patients were divides into CL improved subgroup (IM subgroup) and non-improved subgroup (NIM subgroup).Results: There were improvements on CL and OPCL in both groups. The change of CL and OPCL larger in ACP group (P<0.05) but UAL and LAL were of no significance. NDI and JOA got improvement in both groups at IPO and FFU while ASD was in no difference between SSC and ACP. A total of 40 patients (18 vs 22) acquired CL improvement with a larger population in ACP group. There were no differences on the rate if ASD, NDI, JOA and their change between IM and NIM subgroup and the change of CL were not correlated with NDI, JOA and their change.Conclusion: SSC and ACP both provide long-term efficacy on OPCL correction with little impact on adjacent segment. The improvement of CL after three-level ACDF seems not so essential.