Correlation between the volume of cervical extensors and sagittal parameters of cervical spine in patients with cervical degenerative diseases

English Keywords:Cervical spondylotic  Cervical extensor  Cervical sagittal alignment

English Abstract:

  【Abstract】 Objectives: To explore the relationship between the volume of cervical extensor and the sagittal alignment position in patients with different types of cervical degenerative diseases. Methods: Retrospective analysis was performed on patients with cervical degenerative diseases who were treated in Peking University International Hospital from May 2016 to July 2018. 563 patients(female/male 259/304, average age 53.3±19.6 years) were divided into group A(cervical spondylotic myelopathy, n=208), group B(cervical spondylotic radiculopathy, n=194) and group C(cervical degenerative disease without neurological symptoms, n=161). C2-7cobb angle and C0-2 Cobb angle, C7 slope(C7S) and C2-7 sagittal vertical axis(C2-7 SVA) were measured and recorded using picture archiving and communication systems(PACS). The ratios of superficial extensor area(SEA), deep extensor area(DEA) and vertebra body area(VBA) of C3-7 upper endplate were measured and analyzed by Image J software. The volume of cervical extensor was quantified by SEA/VBA and DEA/VBA. Single-way ANOVA analysis of variance was used to compare the data of each group, and Pearson correlation analysis was used to analyze the possible correlation between the volume of cervical extensor and sagittal parameters. Results: C2-7 Cobb angle of group A(8.64°±6.19°) was significantly lower than that of group B(12.55°±6.27°) and group C(13.08°±5.77°, P<0.05). C7S of group A(28.09°±10.16°) were significantly higher than those of group B(22.26°±7.55°, P<0.05) and group C(21.63°±8.96°, P<0.01). C2-7 SVA of group A(21.77±12.38mm) were significantly higher than those of group B(17.80±10.82mm, P<0.05) and group C(15.54±6.82mm, P<0.01). There was no significant difference in SEA/DEA ratio among all three groups. The DEA/VBA ratio in group A was significantly lower than that in group B and C(P<0.05), among which C3-5 was the most significant levels(P<0.05). In group A, C3 DEA/VBA ratio was weakly negatively correlated with C2-7 SVA(r=-0.379, P<0.05) and C7S(r=-0.311, P<0.05), while C4 DEA/VBA ratio was moderately negatively correlated with C2-7 SVA (r=-0.478, P<0.01) and C7S (r=-0.466, P<0.01), while SEA/VBA ratio was not significantly negatively correlated with sagittal parameters. Conclusions: Cervical sagittal malalignment in patients with cervical spondylotic myelopathy is more significant than that in other types of cervical degenerative diseases. The volume of deep extensors in patients with cervical spondylotic myelopathy is significantly lower than that in other types of cervical degenerative diseases. The volume reduction of the proximal attachment area of deep extensors is significantly correlated with the disorder of sagittal alignment of cervical spine.