Anatomic study and clinical application of transforaminal fenestration approach in lumbar spine

Abstract

Objective To explore the feasibility and clinical effects of transforaminal fenestration approach in lumbar spine.Methods Transforaminal fenestration approach was performed on 30 specimens of adult lumbar spine from L1 to S1 segments,with the exiting nerve root and posterior aspect of disc fully exposed.The resected structures were measured.The 3D CT was performed before and after fenestration,and the structure resected was measured.The 3D CT data of lumbar spine of 31 adult patients were collected and the resected structures were measured.Transforaminal fenestration approach was applied in 10 patients with far lateral lumbar disc herniation.Microendoscopic discectomy was performed with mobile endospine system at level of L3,4 in 2 cases,L4,5 in 4,L5S1 in 4.Results From L1 to S1,the isthmus and laminae gradually extends laterally,the transverse process gradually moves downward,and the distance between the dura sac and the lateral edge of lamina and facet increased.At the segment of L1,2,L2,3 and L3,4,only a small range of structure was resected.At the segment of L4,5 and L5S1,a large range of lamina and faceted were resected,and the dura sac can not be fully exposed.A crescentiform fenestration can preserve more connection of isthmus and lower facet.The transforaminal fenestration approach was successfully used in all the 10 patients,the herniation and sequestered nucleus was exposed fully and removed completely.The follow-up time was 12 months,excellent result was obtained in 8 patients,and good in 2 according to Macnab scale,without instability at dynamic film.Conclusion Transforaminal fenestration approach can provide enough exposition with the preservation of stable structure in lumbar spine,especially with endoscopic surgery and cresceutiform fenestration,and far lateral lumbar disc herniation can be effectively treated in this approach. Key words: Lumbar vertebrae; Intervertebral disk displacement; Anatomy; Treatment outcome