The change of matching between T1 slope and cervical lordosis after anterior and posterior reconstruction surgeries for patients with multilevel cervical spondylotic myelopathy: a retrospective study.

Objective To compare the matching changes between T1 slope (T1S) and cervical lordosis (CL) in patients with multilevel cervical spondylotic myelopathy (CSM) after anterior and posterior reconstruction surgeries. Methods 134 patients with multilevel CSM and a T1S-CLvalue<20° were enrolled from the medical records spanning 2015 to 2020. The anterior group comprised 69 patients who underwent anterior cervical discectomy and fusion (ACDF), or discectomy combined corpectomy hybrid technique. The posterior group included 65 patients who received laminoplasty (LAMP), or laminectomy with fusion (LF). This study retrospectively analyzed perioperative parameters including clinical parameters (Japanese Orthopedic Association (JOA) score, visual analogue scale (VAS), neck disability index (NDI) ) and radiologic parameters (T1 slope, cervical lordosis, C2-7 sagittal vertical axis (SVA)). A P -value less than 0.05 was considered the threshold for statistical significance. Results The average follow-up time was 28.6 months. Prior to surgery, there were no significant differences in factors between two groups ( P ﹥0.05). Postoperatively, while the JOA scores were similar between groups ( P ﹥0.05), the anterior group showed significantly lower in NDI, VAS, perioperative parameters and incidences of complications ( P ﹤0.001). Significant changes were observed in each group for T1S, CL, C2-7 SVA and T1S-CL ( P ﹤0.001). Preoperatively, in anterior group, significant correlations were identified between T1S-CL and T1S, CL and C2-7 SVA ( P <0.05). In posterior group, significant correlations were observed between T1S-CL and T1S, CL and C2-7 SVA ( P <0.05). Following surgery, in anterior group, the correlations persisted between T1S-CL and T1S, CL and C2-7 SVA ( P <0.05). In posterior group, the correlations between T1S-CL and T1S, and CL were not significant( P >0.05), while the correlation between T1S-CL and C2-7 SVA was significant( P <0.001). The comparative analysis of parameter changes between anterior and posterior groups revealed no significant difference in the changes of T1S and C2-7 SVA ( P >0.05), whereas significant differences were observed in the changes of C2-7 lordosis and T1S-CL ( P <0.001). Conclusion Anterior reconstruction surgery can improve or optimize the matching of T1S-CL, while a mismatch of T1S-CL is more likely to occur after posterior surgery, potentially leading to cervical sagittal malalignment and imbalance in patients with multilevel CSM.