| Objective:We measured and recorded the three-demensional(3D)intervertebral phoronomics of volunteer suffering from cervical degenerative disc diseases(CDDDs)with usage of cone beam computed tomography(CBCT)combined with 3D-3D registration technology and did analysis of results,which for providing a biomechanical basis for more in-depth study of the kinematics of the cervical spine in its pathological state at a later stage.Methods:Twenty patients suffering from CDDDs(mean age 48.4 years)were taken in low-radiation CBCT scans of the cervical spine(C1-C7)in seven functional positions.A 3D-to-3D registration was then taken for each vertebral body in the functional positions to calculate the 3D segmental motion characteristics in vivo.Results:1.During the maximum flexion-extension(F-E)motion,the mean ROM of the cervical spine as a whole(C1-C7)was 43.08±10.55°;the ROM of the C1-C2(8.78±3.38°),C3-C4(9.07±2.85°),and C4-C5(9.50±4.14°)segments was significantly greater than that of the other segments(P<0.05),and the C2-C3(5.39±2.04°)and C6-C7(5.36±3.04°)segment ROM was significantly smaller than the other segments(P<0.05);C5-C6 segment was not statistically significant compared with the other segments.None of the segmental couplings coupled significant left-right rotational and lateral bending motion,with a range of 0.46～3.91°on average.The average displacement of C1 relative to C7 in the anterior-posterior(Z-axis)direction was 43.08 ± 10.55 mm,and the coupling displacements of each segment in the left-right(X-axis)and up-down(Y-axis)directions were smaller,ranging from 0.18 ～ 1.40 mm on average.2.During the maximum left and right axial rotation(A-R)motion,the mean ROM of the cervical spine as a whole(C1-C7)was 74.22 ± 11.33°,with C1-C2(52.55 ± 8.60°)having the largest ROM,accounting for approximately 78% of the ROM during rotation of the entire cervical spine;the rotational ROM of the lower cervical spine had no statistically significant difference in ROM compared to each segment(P > 0.05).The coupled anterior-posterior flexion-extension range of motion for each segment ranged from 0.86° to 3.08° on average,and the coupled left-right lateral bending range of motion ranged from 2.58° to 10.03° on average,with the largest coupled lateral bending range of motion being C1-C2(10.03±5.16°).The coupled displacement of each segment of the lower cervical spine in the anterior-posterior(Z-axis)and up-down(Y-axis)directions was insignificant,averaging between 0.10 ～ 1.22 mm;in the left-right(X-axis)direction,the coupled displacement of segment C1-C2 was 7.13 ± 1.26 mm.3.During the maximum lateral bending(L-B)motion,The mean range of motion of the cervical spine as a whole(C1-C7)was 26.48 ± 11.90°;the range of motion of C5-C6(4.33 ± 2.27°)was statistically significant(P < 0.05)when compared with segments C3-C4(7.41 ± 2.51°).The average anterior-posterior flexion-extension range of motion of each segment coupling was between 1.03 and 2.94°;the largest range of motion of coupling left-right rotation was in segment C1-C2(33.90±9.46°);the range of motion of the remaining segments coupling left-right rotation was between 1.03 and 5.74°.The coupling displacements of each segment in the anterior-posterior(Z-axis)and up-down(Y-axis)directions are not obvious and average between 0.14 ～ 0.38 mm;in the left-right(X-axis)direction,the maximum coupling displacement is C1-C2(3.85±1.46 mm),and the coupling displacements of the remaining segments are between 0.57 and 1.42 mm.Conclusions:We measured and recorded the ROM of maximum flexion-extension,left and right axial rotation and lateral bending motion in patients with cervical degenerative disc diseases,providing a theoretical basis for subsequent in-depth phoronomics studies. |
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