The standard parameters and influential factors of cervical spine alignment and range of motion / 中华骨科杂志

ABSTRACT

Objective To establish standard parameters of cervical alignment and cervical range of motion(ROM) in asymptomatic population,and to explore the influential factors such as age,sex and cervical disc degeneration.Methods The cervical standard lateral,flexion and extension plain radiographs of 212 asymptomatic volunteers were analyzed retrospectively.The volunteers,including 128 females and 84 males with ages ranging from 20 to 79 years,were divided into 6 groups from 3rd to 8th decade of life and were divided into 4 groups based on the scoring system of cervical disc degeneration.These plain films were blindly measured by 3 spine surgeons with Mimics software,and each spine surgeon mcasured them for 3 times.Several parameters,including C2-C7 cervical alignment,total ROM,flexion ROM,extension ROM and segmental ROM were measured.The score of disc degeneration were assessed from C2-C3 to C6-C7.Pearson correlation analyses was used to quantify the relation between cervical alignment and total ROM.Multiple linear regression analyses were required to account for influential factors.Inter-and intrarater correlation coefficient was analyzed.Results The C2-C7 cervical alignment was 21.40°± 12.15°,and the total ROM was 63.59°± 15.37°.Sex had a significant impact on the cervical alignment (regression coefficient was-2.472,P ＜ 0.05).Both sex and age had significant impacts on the total ROM (regression coefficient was 3.863 and-6.463 respectively,P ＜ 0.05).Sex had a significant impact on C2,3 and C5,6 segmental ROM; age had a significant impact on all of the five segmental ROM from C2,3 to C6,7; cervical disc degeneration had a significant impact on the C4-5,C5-6 and C6-7 segmental ROM.The cervical alignment had no significant association with both of the extension and total ROM (r=-0.106 and 0.215,respectively,P ＞ 0.05),but had a significantly negative association with flexion angle (r=-0.401,P＜ 0.05).The measurement of cervical alignment,total ROM and segmental ROM showed excellent intra-rater agreement and excellent inter-rater agreement.Conclusion Sex is an influential factor of the cervical alignment.Sex and age are two influential factors of the total ROM.Sex,age and cervical disc degeneration are influential factors of the segmental ROM.The cervical alignments do not have an impact on total ROM.