Fig. 1
From: The optimal introversion angle and length of pedicle screw to avoid L1-S1 vascular damage
LAVC−PGV and DO−AVC with different INTAs in L1-S1, SO−AVC= LAVC−PGV+ DO−AVC. AA: abdominal aorta, IVC: inferior vena cava, LCIA: left common iliac artery, RCIA: right common iliac artery, LCIV: left common iliac vein, RCIV: right common iliac vein. LEIA: left external iliac artery, LIIA: left internal iliac artery, REIA: right external iliac artery, RIIA: right internal iliac artery, DAVC−PGV: the distance between AVC and PGV, AVC: anterior vertebral cortex, PGV: prevertebral great vessels, INTA: introversion angles, L: lumbar, S: sacral. At L1-L5 (figure a, b, c), A, B and C represent the left INTA with 5°, 10° and 15°, respectively; A′, B′ and C′ represent the right INTA with 5°, 10° and 15° respectively. At S1 (figure d), A, B, C ,D represent the left INTA at 0°, 5°, 10° and 15°, respectively; A′, B′, C′ and D’ represent the right INTA at 0°, 5°, 10° and 15° respectively