Applied anatomical and clinical application of the lateral approach to the vertebral lamina for treating extreme lateral lumber dsic herniation

[Objective]To provide microsurgery anatomical data for the surgical operation in treating of extreme lateral lumbar dsic herniation through the observations of the regional anatomic structure about the post-median approach tolateral vetebral lamina(PMALVL).[Method]Thicknesses of intertransverse ligament,the distribution of anterior branches of lumbar nerve and vessel were measured at the adult cadavas specimens.Retrospectively analyzed with 12 cases of extreme lateral lumbar disc herniation from January 2004 to January 2006,including 7 cases were treated by the lateral approach to the vertebral lamina,5 cases treated by PMALVL.[Result]The thickness of intertransverse lingament is 0.6~1.3 mm.More than 90 percent of anterior branches of lumbar segmental arteries and the accompanying veins from L_3 to S_1 were located ventrally in the superior portion of the intertransverse ligament.A branch from Lumbar artery permanently locates in the hfiddle of post-lateral intertransverse ligament.The angle between the anterior branch of Lumbar nerve root and midline sagittal plane is 18.9°~39.2°.The distance from the root of the tranverse to the anterior branch of lumbar nerve root and from the lateral margin of the pars interarticul aris to the anterior branch of lumbar nerve root(5.6~8.0)mm and(1.7~3.6)mm respectively.The period of follow up in 12 cases was from 3 months to 24 months,with an average of 10 months.The resultwas excellentin 8 cases,good in 3 cases,total fine rate according the classification of Nakal was 91.67%.[Conclusion]Intertransvarse ligament is a reliable landmark for PMALVL and treating extreme lateral lumbar disc herniation through PMALVL may get microtraumatic and excellent effect.