Comparative Study Of Kambin’s Triangle Measurements Between The Three-dimensional Reconstruction Based On CT/MRI Image Fusion And Cadaver

Background:With the aging of the population and the change of working and living habits of modern people,the incidence of low back pain is increasing.However,lumbar intervertebral disc herniation is one of the important factors causing low back pain,percutaneous transforaminal endoscopic discectomy(PTED)through the "Kambin triangle" into the inside of the spinal canal,under direct vision through the predural space to loosen the compression,adhesion of the nerve root tissue or directly remove the protruding disc tissue,has been become the most promising spine minimally invasive surgery.However,the most important surgical complication of this type of surgery is nerve root injury.In order to avoid this complication,it is necessary to understand the spatial relationship between the nerve roots and the vertebral body in the Kambin triangle.In recent years,with the continuous development of imaging technology and computer technology,3D reconstruction technology has been gradually utilized in clinical practice,which can provide clinicians with a realistic and effective 3D visualization model to help clinicians understand the patient’s anatomical structure at an angle and at multiple levels.However,most of the current studies focus on cadaveric specimens,which have limitations such as gender,race,region,age and so on.Specimen study can only provide reference for surgery.In practical clinical work,surgeons can only judge the relative spatial location of nerve roots by solid clinical experience and patient imaging data,and can not make accurate judgment.Especially for young surgeons who blindly construct working channels and lack the depth of implantation of operating instruments,it is very likely to cause nerve root injury during release.Therefore,simple anatomical research has been unable to meet the needs of future precise surgical treatment.Therefore,the purpose of this study is to establish a three-dimensional reconstruction model of Kambin triangle region of lumbar spine by fusing CT and MRI imaging data,and to understand the spatial relationship of nerve roots and vertebral in Kambin triangle region,and to verify the deviation of the nerve root and the vertebral body in three-dimensional reconstructions of Kambin’s triangle compared to the anatomy of the cadaver,and to confirm whether the 3D reconstruction model data can truly and effectively reflect the actual anatomical relationship.Purpose:By collecting CT and MRI data of 10 fresh frozen adult lumbar spine specimens,a three-dimensional reconstruction model of Kambin triangle region was established by multi-modal fusion.The difference between 3D model and cadaver measurement of Kambin triangle based on CT/MRI fusion images was compared and its clinical significance was discussed.Methods:Ten fresh lumbar cadavers were taken(6 females and 4 males,aged 39-76 years,mean age 59.5±13.0 years).1.Three-dimensional model data measurement:CT and MRI image data of lumbar spine specimens were obtained and fused to form a 3D reconstruction model.The measurement data included the diameter of the exportation of the nerve root(d),the maximum diameter of the ganglion(D),the angle between nerve root and spinal dura mater(A),the distance between the lateral border of the junction of the upper articular process and the pedicle of the vertebral arch and the exit point of the nerve root in the dura(11),and the horizontal distance from the lateral border of the junction of the upper articular process and the pedicle of the vertebral arch to the dura(12)on the 3D lumbar model.2.Anatomic data measurement:Completely exposing the dura mater and nerve roots,retaining a small amount of soft tissue between the nerve root and the vertebral body to ensure the true anatomical relation of the root and vertebral nerve.The same measurement parameters used in the 3D reconstructed Kambin’s triangle model were assessed with the millimeter caliper and protractor on the cadavers and comparing their differences.Results:1.the three-dimensional reconstruction of Kambin’s triangle based on CT/MRI image fusion provided clear the spatial relationship between the nerve root and the intervertebral foramen.The average absolute error was 0.41±0.24mm,0.43±0.22mm,3.54±1.720,1.56±0.81mm and 1.56±1.03mm,respectively.2.There was no significant difference in paired t test data in each group(d(t=-1.03,P=0.31),D(t=-1.26,P=0.21),A(t=-1.54,P=0.13),11(t =-1.26,P = 0.50)and 12(t =-1.22,P = 0.23)).3.The intra group correlation coefficient(ICC)of the measured data indicated that there was a strong correlation between the 3D-reconstructed Model of Kambin’s Triangle and the cadaveric lumbar(d(r=0.87,p=0),D(r=0.92,p=0),A(r=0.87,p=0),11(r=0.98,P=0),12(r-0.97,p=0)).4.Bland-Altman plot showed the points representing the D-value fluctuate were close to the D-value mean line,with almost all of the D-value points falling within the 95%consistency interval Conclusions:The 3D reconstruction of Kambin’s triangle based on CT/MRI image fusion can accurately and realistically show the Kambin’s triangle of lumbar spine.It may better assist surgeons to reduce the complications of injury of walking nerve root during operation and provides a reliable basis for risk assessment of Percutaneous endoscopic lumbar discectomy(PELD)and achieving accurate,minimally invasive,individualized treatment.