To Evaluate The Dynamic Changes Of Intervertebral Foramen Affected By Lumbar Disk Herniations During Lumbar Extenso-flexal Movement Using640-slice Volumatric CT

ObjectiveTo evaluate the dynamic changes of intervertebral foramen during lumbarextenso-flexal movement in the patients of lumbar disk herniations usingAquilion one640-slice volumatric CT.Methods640-slice dynamic extenso-flexal volume CT was used to perform40patients with LDH by routine static scan. The cobb angles were measured todetermine the lumbar curves during the scanning process. The LDH(L3-S1) andIVF in the static and dynamic situations were measured and compared throughMPR process in different angles.ResultsAll patients were satisfied with the images by dynamic extenso-flexallumbar volume CT：1、The grades Ⅲ and Ⅳ of LDH were rising from the movement ofhyperflexion to hyperextension. The LDHs of grade Ⅲ and Ⅳ of20°hyperextension and and standard0°were58.21%and10.44%, respectively.There were significant difference in statistics(P<0.05).2、The areas of IVFs decreased12.15±0.24mm2at per10° hyperextension position.88%foramens reduced in size by6.58±0.12mm~2at10°hyperflexion position.3、The VAS scores of low back and leg pain at standard0°were3132±120and2885±119. The VAS scores of low back and leg pain of hyperflexion20°were3734±125and1103±136, the low back pain was not significantdifference in statistics (t=327, P>0.05), but the leg pain was significantdifference in statistics (t=-76, P<0.01).4、Radiation dose of X-ray tube current70mA with dynamic scan wasobviously lower than that of routine static scan. The image qualities were good.ConclusionsDynamic extenso-flexal scan may get high quality images at differenthyperflexion and hyperextension lumbar positions with relatively low X-ray dose.It can provide more information for clinical evaluation the relationship of LDHand IVF during lumbar movement.