The characteristic and significance of normal human lower lumbar nerve root and vertabral interlaminar space under CT volume rendering technique

English Keywords:Lower lumbar  Nerve root  CT volume rendering technique  Full-endoscopic technique  Image measurement

English Abstract:

  【Abstract】 Objectives:　To investigate the characteristic of the normal human lower lumbar nerve root and interlaminar space under CT volume rendering technique, and to provide the basis for safe practice of the full-endoscopic technique. Methods: From September 2011 to November 2011, CT volume rendering technique was performed on lumbar nerve root and interlaminar space of 60 healthy population. There were 32 males and 28 females with a mean age of 40(20-59) years old. Three-dimensional reconstruction data of lower lumbar spine under 64-slice spiral CT were transferred into working station, multi-planar reconstruction(MPR) technique was used to obtain the sagittal, coronal and cross sectional imaging, the starting point of nerve root was determined, then the imaging of lower lumbar nerve root and vertabral interlaminar space was obtained under CT volume rendering technique(VRT). Index included: the vertical diameter(VD) and longitude diameter(LD) of interlaminar space; the vertical distance from nerve root to the superior edge of pedicle(PSRD), the vertical distance from nerve root to the inferior edge of pedicle(PIRD); the vertical distance from nerve root to the superior edge of vertebral lamina(LSRD), the vertical distance from nerve root to medial edge of the facet(LMRD); the straight distance from nerve root to the inferior edge of pedicle(RSD); the angle between nerve root and dura mater(RA). Each parameter was statistically analyzed. Results: All images of lower lumbar nerve root and vertebral interlaminar space from 60 cases were obtained under CT volume rendering technique. Four types were determined according to the position of nerve root and interlaminar space: superior edge and medial, superior edge and outside, inferior edge and medial, inferior edge and outside. However, there was statistical significance with adjacent segment parameters(P<0.05). The values of VD, LD,　PSRD,　PIRD,　LSRD,　LMRD and RSD increased gradually from L4 to S1; on the contrary, the RA decreased gradually from L4 to S1, and the length of nerve root in the spinal canal increased gradually. Conclusions: The morphology of the lower lumbar nerve root and interlaminar space can be accurately detected by CT volume rendering technique, which can be used for the surgical treatment of lumbar disc herniation under full-endoscopic technique.