Vascular anatomy anterior to the lower lumbar spine and its clinical significance

Objective:To provide anatomic data of abdominal aorta,inferior vena cava and their branches related the lower lumbar spine surgery.Method:The abdominal aorta and inferior vena cava from 40 human cadavers were dissected,the anatomic morphometry and varieties of major blood vessels and their branches anterior to the lower lumbar spine were respectively documented,and finally the approachable space of each intervertebral disc were measured and coompared before and after blood vessel′s release.Result:The distance from the abdominal aorta bifurcation and common iliac vein confluence to the proximal margin of L5S1 disc was 5.6±2.2cm and 2.9±1.8cm respectively.Overall,the bifurcation level had a greater anatomic varieties than the confluence level,but,as for every specimen,the bifurcation located at the cranial level of the confluence without exeption.The mural branches of abdominal aorta were relatively stable in their orientation,course and outer diameter,the mural branches of great vein especially the iliolumbar veins and the ascending lumbar veins.were,conversely,much more variable in their anatomic configuration,After sufficient release of peridiscal great blood vessels,the ratio of the accessible space at L34,L45,L5S1 level related to the transverse diameter of corresponding intervertebral disc were 96.2%,90.0% and 97.6% respectively.Conclusion:The aorta bifurcation and common iliac vein confluence mostly hamper the exposure of L45 and L34 disc.The mural branches of peridiscal great vein are more variant and the injury to them is the most common cause of incontrolled bleeding intraoperative.The approachable space of L45 intervertebral disc is most restricted in practical operation.