Location Of Intervertebral Space And Cervical Nerve Of Percutaneous Posterior Endoscopic Cervical Discectomy Under Endoscopy By Digital Imaging Study

Objective:To determine the position of endoscopic intervertebral space in percutaneous cervical posterior endoscopic discectomy by 3D-CT,so as to find out the protrusion of cervical intervertebral disc and improve the safety,efficacy and efficiency of operation.(2)Methods:(1)Seventeen patients with cervical spondylosis who met the criteria were scanned by CTM.The 3D-CT images of cervical spine were reconstructed by Mimics 16.0 software,and the C4/5-C7/T1 segments were observed.(2)On the 3D-CT images of the cervical spine,two new planes of vertically perpendicular cervical vertebral laminae were constructed to determine the intersection point(O)between the medial vertical line of the posterior facet joint space and the inner and lower end of the inferior facet.The spinous process,part of the lamina and dura were removed by image processing technology,and the complete intervertebral space and part of the vertebral body were exposed.(3)Observe the shape and position of cervical intervertebral space and its adjacent structures.Cross sections were established at each point:the intersection point(O)of the medial end of the posterior facet joint space and the inferior end of the inferior facet,the intersection point(B)of the posterior inferior edge of the upper vertebral body and the posterior midline of the vertebral body,and the intersection point(C)of the posterior superior edge of the lower vertebral body and the posterior midline of the vertebral body.Sagittal planes were established at each point:point B,point O,the posterior most lateral end of the intervertebral space(A),point O,horizontal lateral dural margin;sagittal planes measured vertical distances:O and B(a),O and C(b),B and C(c);coronal planes measured vertical distances:O and A(d),A and lateral dural margin(e),through the posterior widest part of the same level intervertebral space of B and A(f),through the posterior widest part of the same level intervertebral space of B and O(g),through the posterior widest part of the same level intervertebral space of B and lateral dural margin.(H).(4)Statistical analysis of data.Results:(1)The upper margin of cervical intervertebral space was the lower margin of the upper vertebral body,and the lower margin was the upper margin of the lower vertebral body and continued with the upper margin of the posterolateral uncinate process.The level of intervertebral space corresponds but does not extend to the lateral margin of uncinate process.Posterior view of cervical intervertebral space:C2/3?C3/4 is transverse crescent-shaped,the upper margin is horizontal,the middle margin is widest,and the two ends gradually narrow;C4/5 is nearly parallel to the upper and lower margins;C5/6 and C6/7 is transverse rugby-shaped;C7/T1 is jube-shaped.(2)In C4/5-C7/T1 segment,the distance between O point and the intersection point of posterior lower edge of upper vertebral body and posterior midline of vertebral body was(0.12 ±2.52mm-2.09 ±3.28mm),the distance between O point and posterior upper edge of lower vertebral body and the intersection point of posterior midline of vertebral body was(1.21±2.92mm-3.40±2.23mm),and the distance between posterior lower edge of upper vertebral body and posterior midline of lower vertebral body and the intersection point of posterior midline of vertebral body and posterior midline of vertebral body was(3.53±0.80mm).The distances between the O-point and the posterior most lateral end of the intervertebral space were(3.14±1.68mm-5.34 ±2.96mm).The distances between the posterior most lateral end of the intervertebral space and the lateral edge of the horizontal dura mater at the O-point were(0.48±2.38mm-1.50±1.39mm).The distances between the posterior most lateral end of the intervertebral space and the posterior widest part of the intervertebral space at the same level were(6.96±1.33mm-8.58mm).The distances between the O-point and the posterior part of the intervertebral space at the same The distance between the widest part of the squareness and the widest part of the posterior intervertebral space of the same segment was(10.67 ± 2.79 mm-12.40±3.29 mm)and(5.77±2.52 mm-7.50 ±2.62 mm)respectively.(3)In the C4/5?C7/T1 segment,the distance between O point and posterior inferior margin of upper vertebral body(a),the distance between posterior inferior margin of upper vertebral body and posterior superior margin of lower vertebral body(c),the distance between O point and posterior median line of vertebral body(g),the distance between O point and the posterior most lateral end of intervertebral space(h)were different,but there was no significant difference(P>0.05);in the C4/5?C6/7 and C7/T1 segments,the distance between O point and posterior superior margin of lower vertebral body.There were significant differences in distance from(b)(P<0.01),distance between the posterior most lateral end of the intervertebral space and the lateral edge of the dura mater(e)(P<0.001);in segments C4/5,C6/7-C7/T1 and C5/6,the distance between O point and the posterior most lateral end of the intervertebral space(d)was significantly different(P<0.01),and the distance between the posterior most lateral end of the intervertebral space and the widest and the posterior part of the intervertebral space(f)was different.The difference has statistical significance.Conclusion:(1)O-point is an easily identifiable,definite and constant bone marker under endoscopy.(2)The cervical interval corresponds to the level of O point in the same order.(3)In C4/5?C7/T1,the distance between O-point and the widest posterior intervertebral space was(10.67 ±2.79 mm-12.40 ± 3.29mm).Except for C5/6 segment,the distance between O point and the posterior most lateral end of intervertebral space was(3.14±1.68mm-3.71 ± 2.08mm),and the posterior most lateral end of intervertebral space was close to the lateral edge of dura mater.The lateral dural margin was(5.77 ± 2.52mm-7.50 ± 2.62mm)inward,reaching the widest posterior intervertebral space.PPECD endoscopy can locate the cervical intervertebral space at O point.Combined with the patient's imaging examination,it is helpful to find the prominent cervical intervertebral disc accurately and quickly.