RESUMO
BACKGROUND: Cervical sagittal parameters and paravertebral muscle degeneration are important factors for the occurrence of cervical spondylotic myelopathy. However, the relationship between the 2 risk factors and cervical kyphosis following cervical laminoplasty remains unknown. METHODS: A total of 130 patients undergoing cervical laminoplasty were enrolled from July 2018 to July 2020 and were followed up for at least 24 months. Clinical recovery was recorded, including the Japanese Orthopedic Association, neck disability index and visual analog scale scores. Radiographic sagittal parameters were measured on cervical lateral radiographs: T1 slope (T1S), C2-C7 Cobb lordotic angle (CLA), C2-C7 sagittal vertical axis, O-C2 angle, and T1S-CLA. The magnetic resonance imaging (MRI) parameters of the paraspinal muscles were also measured, including cross-sectional area and fat infiltration (FI). The patients were divided into a kyphosis group and a lordosis group based on the last follow-up results of CLA. Multivariate logistic analysis was performed to analyze risk factors for kyphosis following laminoplasty. RESULTS: Thirty-two patients were assigned to the kyphosis group and 98 were assigned to the lordosis group. Patient baseline and surgical information in the 2 groups showed no statistically significant difference. In the comparison of clinical recovery, patients with kyphosis showed a lower Japanese Orthopedic Association recovery rate than the lordosis group. For the radiographic parameters and muscle condition comparison, CLA, T1S-CLA, and FI were the most significant parameters. The logistic regression revealed that T1S-CLA and FI were the most important variables that predicted kyphosis. CONCLUSIONS: We concluded that FI remarkably differed in the paraspinal muscles in the 2 groups. Multivariate logistic regression demonstrated that T1S-CLA and FI significantly influenced the process of kyphosis after cervical laminoplasty.
