[Prediction of cervical curvature loss after expansive open-door laminoplasty based on sagittal parameters]

To evaluate the impact of preoperative cervical sagittal parameters on the loss of cervical lordosis (LCL) after expansive open-door laminoplasty (EOLP) and explore the optimal predictors.

A retrospective analysis was performed on the clinical data of 94 patients with cervical spondylotic myelopathy who underwent EOLP from January 2019 to January 2021, including 61 males and 33 females, aged 34 to 75 years old with an average age of(53.1±9.7) years old. Preoperative routine anteroposterior, lateral, and dynamic X-ray films of the cervical and thoracic spine were taken to comprehensively assess various cervical sagittal parameters: T₁ slope (T₁S), C₂-C₇ sagittal vertical axis (C₂-C₇ SVA), C₂-C₇ cervical lordosis (CL), T1 slope-cervical lordosis (T₁S-CL), cervical lordosis/T₁ slope (CL/T₁S), C₂-C₇ cervical range of motion (ROM), thoracic kyphosis (TK), cephalad vertebral level undergoing laminoplasty (CVLL), and C_2,3 disc angle. Statistical analysis was conducted to identify the independent risk factors of preoperative sagittal parameters for postoperative LCL.

A total of 94 patients meeting the inclusion and exclusion criteria were enrolled, with a postoperative follow-up period of 12 to 24 months. Pearson correlation analysis showed that T₁S, T₁S-CL, CVLL, and C_2,3 disc angle were significantly correlated with postoperative LCL, while C₂-C₇ SVA, CL, CL/T₁S, C₂-C₇ ROM, and TK had no significant correlation with postoperative LCL. Regression analysis further indicated that T₁S (β=0.426, P<0.001), T₁S-CL (β=0.716, P<0.001), C_2,3 disc angle (β=0.351, P<0.001), and CVLL (β=-3.348, P<0.001) were significantly correlated with postoperative LCL.

For patients with cervical spondylotic myelopathy treated with EOLP, T₁S, T₁S-CL, CVLL, and C_2,3 disc angle are important factors for predicting cervical lordosis loss, among which CVLL may be the most critical predictive indicator.