Comparative study of Kambin′s triangle measurements between the three-dimensional reconstruction based on CT/MRI image fusion and cadaver

English Keywords:Three-dimensional reconstruction  Anatomy  Individualized treatment  Kambin′s triangle

English Abstract:

  【Abstract】 Objectives: To identify the deviation between the real data and the three-dimensional(3D) reconstruction of Kambin′s triangle based on CT/MRI image fusion, and to determine its clinical significance. Methods: Ten fresh lumbar cadavers were harvested, 6 females and 4 males, aged 39-76 years(average, 59.5±13.0 years). 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 nerve root(d), the maximum diameter of ganglion(D), the angle between nerve root and spinal dura mater(A), the distance between the lateral border of the junction of upper articular process and the pedicle of vertebral arch and the exit point of the nerve root in the dura(l1), 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(l2) on the 3D lumbar model. Anatomic data measurements were performed: 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 in the 3D reconstructed Kambin′s triangle model were assessed with the millimeter caliper and protractor on the cadavers and the differences were compared. Intra-group correlation coefficient(ICC) and Bland-Altman plot were used to analyze the consistency between sample measurement data and Kambin triangulation model measurement data. Results: The 3D 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 of d, D, A, L1 and l2 was 0.41±0.24mm, 0.43±0.22mm, 3.54°±1.72°, 1.56±0.81mm and 1.56±1.03mm, respectively. 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), l1(t＝-1.26, P＝0.50) and l2(t＝-1.22, P＝0.23)]. 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), D(r=0.92), A(r=0.87), l1(r=0.98), l2(r=0.97)]. Bland-Altman plot showed the points representing the D-value fluctuate close to the D-value mean line, and 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 achieve accurate, minimally invasive, individualized treatment.