Imaging Study Of The Full-endoscopic Interlaminar Approach For The Surgical Treatment Of Lumbar Disc Herniations

ObjectiveTo perform the radiogical measurement on the lower lumbar nerve root and vertebral laminae relevant anatomy parameter and to explore the feasibility of full-endoscopic interlaminar approach (FEIL) for the surgical treatment of L3/4、L4/5and L5/S1lumbar disc herniations.MethodsWe do lumbar vertebra scan and lower lumbar vertebra three dimensional reconstruction by64row spiral CT, volume rendering and multiple planar reformatting technology, respectively. The following parameters were measured. Parameters included:the vertical distance from nerve root to the superior edge of vertebral laminae, the vertical distance from nerve root to the superior edge of vertebral laminae, the vertical distance from nerve root to the inferior edge of intervertebral disc, the vertical distance from nerve root to medial edge of the facet, the vertical distance from nerve root to the midline of spinal canal. According to the position of nerve root, we determined the standard of fenestration and performed fenestration. We measured lamina abduction angle, the vertical diameter and longitude diameter of interlaminar space, the length,width and facet length of inferior articular process before and after fenestration. Each parameter was statistically analyzed and the area of fenestraion was calculated.ResultThe vertical distance from nerve root to the midline of spinal canal and the superior edge of vertebral laminae decreased gradually from L4to S1. The vertical distance from nerve root to the the superior edge of vertebral laminae and to medial edge of the facet increased gradually from L4to S1. Superior edge type:92vertebral laminaes (L3/46、L4/516、L5/S170)were not performed fenestration and102vertebral laminaes (L3/438、L4/556、L5/S18) were performed fenestration. The area of fenestration decreased gradually from L3to L5. At the segment of L3/4, a large range of faceted were resected. At the segment of L4/5, a small range of structure was resected. At the segment of L5/S1, only a small range of structure was resected. All of the inferior edge type including46vertebral laminaes (L3/436、L4/58、L5/S12) needed fenestration. The area of fenestration were large and changed little between different segments.ConclusionSuperior edge type of L4/5or L5/S1lumbar disc herniations can be effectively treated in full-endoscopic interlaminar approach; inferior edge type of L4/5or L5/S1lumbar disc herniations and L3/4lumbar disc herniations were not suitable for FEIL.