Introduccion Tenemos como objetivo, cuantificar los cambios de la lordosis fisiologica en las distintas posiciones, de pie y en decubito ventral, sobre el Soporte de Cirugia Espinal (SCE) y evaluar indirectamente los cambios de diametro de los distintos foramenes, midiendo la distancia interpedicular Materiales y metodos 20 pacientes de 20 a 40 anos Se tomaron radiografias, en posicion de pie y sobre el SCE Se midio la lordosis lumbar en radiografias de pie, y sobre el SCE en dos posiciones (baja/alta) asi como la distancia interpedicular de los foramenes de cada segmento Resultados Se constata una perdida de la lordosis en la primera posicion de 21,65° (37,00%) y en la segunda posicion de 28,75° (49,14%) Encontramos un aumento de la distancia interpedicular en todos los niveles tanto en la posicion baja como alta del SCE Los foramenes que presentaron mayor apertura fueron los segmentos de L4-L5, seguidos por L5-S1 Conclusiones Se encontro una perdida promedio de la lordosis fisiologica del 37,00% y del 49,14% con la utilizacion del SCE en las dos posiciones utilizadas En todos los casos existio un aumento de la distancia interpedicular, que vario entre un 10 y un 15% Los foramenes que mayor apertura presentaron en las distintas posiciones fueron los segmentos L4-L5 seguido por L5-S1 La cifotizacion de los segmentos moviles permitirian una mejor liberacion sacorradicular al aumentar el diametro del canal y los foramenes Nivel de Evidencia: IV Background The aim of this study is to quantify the changes of the physiological lordosis in the different positions, standing and in ventral decubitus, on a Spinal Surgery Table (SST), and indirectly evaluate the changes in diameter of the different foramina, and measuring the interpedicular distance Methods The study included 20 patients from 20 to 40 years old X-rays were taken in standing position and on the SST Lumbar lordosis was measured using the X-rays in the standing position, and on the SST in two positions (low/high), as well as the interpedicular distance of the foramina of each segment Results A loss of lordosis was found in the first position of 22 65° (37 00%) and in the second position of 28 75° (49 14%) An increase was found in the interpedicular distance at all levels in both the low and high position of the SST The foramina with the greatest opening were the L4-L5 segments, followed by L5-S1 Discussion A mean loss of 37 00% and 49 14%, respectively, was found in the physiological lordosis with the use the SST in the two positions used In all cases there was an increase in the interpedicular distance, which varied between 10% and 15% The foramina with the greatest openness in the different positions were segments L4-L5 followed by L5-S1 The kyphotisation of the mobile segments would allow a better sacrum-radicular release when increasing the diameter of the channel and the foramina Evidence Level: IV