| Background and purpose:Cervical degeneration is more common in clinic.Because facet joints and intervertebral discs are considered as two key factors causing cervical degeneration,the relationship between sagittal angle asymmetry of facet joints and facet joint degeneration and the degree of disc degeneration has been controversial.There are few domestic reports on this aspect.Therefore,the purpose of this study is to explore the correlation between sagittal asymmetry angle of cervical facet joint and facet joint degeneration and intervertebral disc degeneration from the perspective of solid anatomy and imaging.This study includes the following two parts:Experimental procedures and methods:1.20 fresh adult cadaver specimens of whole cervical spine(C1-C7)were fixed and preserved in formalin.Each specimen was excluded from spinal deformity,vertebral fracture,cervical spine tumors,cervical spine trauma,surgery,osteolytic lesions and other abnormalities or abnormalities,so as to ensure that the specimens had no structural damage and obvious cervical spine diseases.The specimens were dissected layer by layer,the muscles around the vertebral body were carefully removed,the anterior and posterior longitudinal ligaments were retained,and the structures of facets,articular capsules,intervertebral discs,transverse processes and spinous processes were avoided.After numbering 20 cadaver specimens of the whole cervical spine,the facets of C3/4-C6/7 were scanned by spiral CT in neutral position.The angle between facets and the mid-sagittal plane of the vertebral body was measured.Noren’s method was used to calculate the angle difference and grading of the left and right facet joints.According to Pathria’s criteria,facet osteoarthritis(degenerative degree)was classified into four grades.(2)According to the criteria of Pfirrmann et al.,the degeneration of intervertebral disc was classified into four grades.2.20 fresh adult cadaveric specimens of whole cervical vertebra C2-C7 were separated completely.First,the soft tissues and anterior longitudinal ligaments aroundthe cervical vertebra were removed,so that the upper and lower cartilage plates of the intervertebral disc could be easily distinguished from the lower and upper bones of the upper and lower vertebrae.The articular capsules were carefully cut with a sharp knife,and the facet surfaces were not damaged.The upper and lower facets were separated and the articular surfaces were exposed.The transverse and sagittal diameters of intervertebral disc and nucleus pulposus were measured with vernier caliper.(2)Observe the degeneration degree of facet articular surface of each segment and divide the articular cartilage degeneration into four degrees and five regions according to Wang’s classification criteria.(3)Measuring the transverse and upper and lower diameters of the articular surfaces of each cervical segment with vernier calipers.Research methods and contents:1.The relationship between the average sagittal angle and asymmetry of facet joints and the degree of facet joint degeneration in each segment of cervical spineIn this study,the sagittal angles of 18 cervical spine segments(C3-C7)were measured by CT scanning,and 144 facet angles were obtained.The sagittal angle of facet joint was measured by CT scanning,and the degree of facet joint asymmetry was graded according to Noren’s method.At the same time,according to Pathria’s criteria,the degree of facet joint degeneration was divided into four grades.The correlation between facet joint asymmetry group and symmetry group and the degree of facet joint degeneration was compared by nonparametric rank sum test in C3-C7 segments.2.The relationship between cervical facet joint asymmetry and intervertebral disc degenerationSeventy-two intervertebral disc degeneration were graded by MRI scan,and according to Pfirrmann’s criteria,the intervertebral disc degeneration was classified into four grades.To compare whether there is a significant correlation between facet joint asymmetry and the degree of intervertebral disc degeneration in C3-C7 cervical segments.3.The relationship between cervical intervertebral disc degeneration and facet joint degeneration144 cervical facet joints and 72 intervertebral discs were graded.Searman statistics were used to compare the correlation between cervical intervertebral disc degeneration and facet joint degeneration.4.To explore the relationship between facet and facet asymmetryThe transverse and upper and lower diameters of 288 facets of 18 cervical spine specimens were measured with electronic vernier calipers.By independent T-test of two samples,whether the transverse and upper and lower diameters of cervical facet surface are different between the facet asymmetry group and the symmetrical group.5.The consistency of imaging grading and solid anatomical grading of cervical facet degenerationBy observing 288 facets with naked eyes and grading the facet degeneration according to the grading standard proposed by Wang et al.,we can verify the reliability of clinical CT imaging evaluation by comparing the degree grading of facet degeneration with that of solid observation.Result:1 The sagittal angles of facet joints of 18 cervical spine segments(C3-C7)were measured by CT scanning,and 144 facet angles were obtained.There were 31 groups with asymmetric sagittal angles of facet joints,5 in C3/4,9 in C4/5,8 in C5/6 and 9in C6/7.Among them,15 were mildly asymmetric in degree II,12 moderately asymmetric in degree III and 4 severely asymmetric in degree IV.Of 144 cervical facet joints,46(31.9%)were in grade I,76(52.8%)in grade II,20(13.9%)in grade III and 2(1.4%)in grade IV.Nonparametric rank sum test showed that there was no significant difference between asymmetric facet joint group and symmetric facet joint group in the degree of facet joint degeneration.2.Seventy-two disc degenerations were graded by MRI scans,of which 5(6.9%)were grade I,53(73.6%)were grade II,9(12.5%)were grade III and 5(6.9%)were grade IV.In C3/C4,C4/C5,C5/6 and C6/7 segments,no significant correlation was found between facet joint asymmetry and the degree of disc degeneration(P > 0.05).3 The transverse and upper and lower diameters of 288 facets of 18 cervical spine specimens were measured by electronic vernier caliper.Two independent T-tests showed that there was no difference in the upper and lower transverse diameters,leftand right transverse diameters of each cervical segment(P > 0.05),and there was no significant difference in the upper and lower diameters and left and right diameters of the upper and lower articular surfaces(P > 0.05).Therefore,the transverse and upper and lower diameters of the facet joints of C3/4,C4/5,C5/6 and C6/7 segments can be obtained from the corresponding data of the four articular surfaces.The transverse diameter of C3/4-C6/C7 articular surface showed an increasing trend,but the change trend of the upper and lower diameters was not obvious.Independent T-test showed that there was no significant difference in the transverse and upper and lower diameters of cervical facet surface between the facet joint asymmetry group and the symmetrical group(t1 = 0.15,P = 0.884 > 0.05;T2 = 1.28,P = 0.25 > 0.05).Four pairs of 144 cervical facet degeneration grades and 72 cervical disc degeneration grades were analyzed.Among the five segments classified as grade I,facet degeneration had 2 in grade I,6 in grade II and 2 in grade III.There were 53 segments classified as grade II degeneration,including 39 in grade I,53 in grade II,12 in grade III and IV.Grade I degeneration included 4,8,6,and no grade IV degeneration in 9 degenerative segments with grade III intervertebral discs.Five degenerative segments with grade IV intervertebral discs included 1,9,and no grade III and IV degeneration in facet joints.Searman’s statistical analysis showed that in the C3-C7 segment of cervical spine,the facet joints degenerated into 1,9 and no grade III and IV degeneration in cervical spine.There was no significant relationship between facet joint degeneration and intervertebral disc degeneration(r = 0.139,P =0.104 > 0.05).Conclusion:1.No significant correlation was found between sagittal asymmetry of cervical facet joint and degree of facet joint degeneration;2.There was no correlation between sagittal asymmetry of cervical facet joint and degree of disc degeneration;3.There was no significant relationship between cervical disc degeneration and facet joint degeneration;4.In C3/4-C6/7,the transverse diameter of cervical facet joint increased,and the size of upper and lower cervical facet joints changed irregularly.The transverse and upper and lower diameters of cervical facet were not significantly different from those of the symmetrical facet group.5.The degeneration of cervicalfacet had poor consistency between the imaging grading and the solid anatomical grading.The imaging evaluation of facet degeneration could not really reflect the real situation of facet degeneration. |
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