Anatomical Study And Possible Clinical Significance Of The Intervertebral Vein In The Lumbar Intervertebral Foramina

Background&Objective:With the development of minimally invasive spine surgery,lumbar transforaminal epidural steroid injection and Percutaneous lumbar transforaminal endoscopic discectomy have become safe and effective surgery for low back pain.These two minimally invasive techniques have gradually been widely used by spinal surgeons,while the corresponding complications have also emerged.Therefore,many scholars have studied the anatomical structure of the lumbar intervertebral foramina in detail,especially the spatial location of the ligaments and arteries in the intervertebral foramina and the adjacent relationship with nerve roots.However,few scholars have studied the anatomical structure of vertebral venous plexus,especially the he anatomical structure of branches of the lumbar intervertebral veins.Therefore,the purpose of this study is to elucidate the anatomical structure of branches of the lumbar intervertebral veins,improve the anatomical statistics of branches of the lumbar intervertebral veins in China,and provide basic applied anatomical knowledge of branches of the lumbar intervertebral veins,so as to help clinicians avoid the injury of branches of the lumbar intervertebral veins,reduce vascular injury of the lumbar intervertebral veins,and then further improve the minimally invasive spinal technique effectively and safely.Methods:10 complete formalin-preserved adult lumbosacral spine specimens were taken,including 8 males and 2 females(aged 35 to 85 years,average 50 years).Under the operation microscope,the adipose tissue,ligaments and arterial vessels inside and outside the intervertebral foramina were carefully removed,and the dural sac,nerve root and branches of the intervertebral veins were completely exposed.The course and distribution of branches of the intervertebral veins and its adjacent relationship with nerve roots were observed in 100 lumbar intervertebral foramina,and their external diameter and length(accuracy 0.01 mm)were measured.Results:At a rate of 100%,branches of the intervertebral vein were observed in the 100 lumbar intervertebral foramina of 10 embalmed human cadavers examined in our study.The following four types of branches of the intervertebral vein were routinely found:Type I in 27(27%)of the intervertebral foramina in which a superior branch of the intervertebral vein ran along the inferior margin of the vertebral pedicle;Type II in 18(18%)of the intervertebral foramina in which an inferior branch of the intervertebral vein ran along the superior margin of the inferior vertebral pedicle;Type III in 41(41%)of the intervertebral foramina in which the intervertebral vein were divided into a superior and inferior branch:respectively ran along the inferior and superior margin of the vertebral pedicle;and Type ? in 14(14%)of the intervertebral foramina in which the intervertebral vein were divided into two superior branches and an inferior branch.And all of branches of the intervertebral vein were connected laterally with the ascending lumbar vein,lumbar vein,or branches of the Common iliac vein after leaving the intervertebral foramina.Conclusions:Branches of the intervertebral vein are important anatomic structure in lumbar intervertebral foramen.During the operation of lumbar transforaminal epidural steroid injection or percutaneous lumbar transforaminal endoscopic discectomy,it may cause the drug to slip into branches of the intervertebral vein or the injury of the intervertebral veins,and then reduce the effectiveness and safety of the operation.Therefore,clinicians should fully understand the anatomical structure of the lumbar intervertebral veins,which may have a certain clinical guiding significance in spinal minimally invasive surgery.