STUDY DESIGN: Positional magnetic resonance imaging (MRI) study of control subjects. OBJECTIVES: To determine dimensional changes in the lumbar dural sac as a function of posture, and to establish changes between the supine, erect and seated positions. SUMMARY OF BACKGROUND DATA: Studies using computerized tomography and MRI were done to determine the mechanical effects on the lumbar spinal canal in the different positions. There has been no consecutive study, however, in which normal individuals were investigated for positional changes of the dural sac, including true standing position. METHODS: Thirty-two male asymptomatic volunteers were recruited. The examination was performed using a new MRI system. All subjects were examined with sagittal T2 and axial T1-weighted spin-echo images. The subjects were studied in the supine, standing, and sitting positions. The measurements were made using OSIRIS software (Digital Imaging Unit University Hospital of Geneva, Geneva, Switzerland). On axial images, dural sac cross-sectional area and anteroposterior (AP) dural sac diameter were measured at the level of the L3/4, L4/5, and L5/S1 discs. On midsagittal images, AP dural sac diameter and the upper-endplate angles of L1 and S1 were measured. RESULTS: We found a disc degeneration or disc protrusion in 41% (12/29) of the subjects, but there was no obvious compression of the dural sac. Depending on the postures, the mean dural sac cross-sectional area and AP dural sac diameter changed. At all levels, mean dural sac cross-sectional area in the supine position was significantly smaller than in other postures. The dural area decreased most at the L5/S1 level due to positional change from standing to supine. The largest dural area at the L5/S1 level was in sitting extended. AP dural sac diameter on axial and midsagittal images showed a similar tendency. CONCLUSIONS: A significant posture-dependent difference of the dural sac cross-sectional area at the level of intervertebral disc in asymptomatic volunteers has been demonstrated. When the posture changed from supine to standing position, lumbar dural sac volume expanded by the increased pressure of cerebrospinal fluid, and the dural sac cross-sectional area increased. The smallest values were found in the supine position.
STUDY DESIGN: Positional magnetic resonance imaging (MRI) study of control subjects. OBJECTIVES: To determine dimensional changes in the lumbar dural sac as a function of posture, and to establish changes between the supine, erect and seated positions. SUMMARY OF BACKGROUND DATA: Studies using computerized tomography and MRI were done to determine the mechanical effects on the lumbar spinal canal in the different positions. There has been no consecutive study, however, in which normal individuals were investigated for positional changes of the dural sac, including true standing position. METHODS: Thirty-two male asymptomatic volunteers were recruited. The examination was performed using a new MRI system. All subjects were examined with sagittal T2 and axial T1-weighted spin-echo images. The subjects were studied in the supine, standing, and sitting positions. The measurements were made using OSIRIS software (Digital Imaging Unit University Hospital of Geneva, Geneva, Switzerland). On axial images, dural sac cross-sectional area and anteroposterior (AP) dural sac diameter were measured at the level of the L3/4, L4/5, and L5/S1 discs. On midsagittal images, AP dural sac diameter and the upper-endplate angles of L1 and S1 were measured. RESULTS: We found a disc degeneration or disc protrusion in 41% (12/29) of the subjects, but there was no obvious compression of the dural sac. Depending on the postures, the mean dural sac cross-sectional area and AP dural sac diameter changed. At all levels, mean dural sac cross-sectional area in the supine position was significantly smaller than in other postures. The dural area decreased most at the L5/S1 level due to positional change from standing to supine. The largest dural area at the L5/S1 level was in sitting extended. AP dural sac diameter on axial and midsagittal images showed a similar tendency. CONCLUSIONS: A significant posture-dependent difference of the dural sac cross-sectional area at the level of intervertebral disc in asymptomatic volunteers has been demonstrated. When the posture changed from supine to standing position, lumbar dural sac volume expanded by the increased pressure of cerebrospinal fluid, and the dural sac cross-sectional area increased. The smallest values were found in the supine position.
Authors: Yvonne Yan On Lau; Ryan Ka Lok Lee; James Francis Griffith; Carol Lai Yee Chan; Sheung Wai Law; Kin On Kwok Journal: Eur Spine J Date: 2017-07-12 Impact factor: 3.134
Authors: Greger Lønne; Bent Ødegård; Lars Gunnar Johnsen; Tore K Solberg; Kjell Arne Kvistad; Øystein P Nygaard Journal: Eur Spine J Date: 2014-02-27 Impact factor: 3.134
Authors: Jun Miao; Shaobai Wang; Won Man Park; Qun Xia; Xiutong Fang; Martin P Torriani; Kirkham B Wood; Guoan Li Journal: Spine J Date: 2013-03-27 Impact factor: 4.166
Authors: Alessandra Splendiani; Marco Perri; Giuseppe Grattacaso; Valeria Di Tunno; Claudia Marsecano; Luca Panebianco; Antonio Gennarelli; Valentina Felli; Marco Varrassi; Antonio Barile; Ernesto Di Cesare; Carlo Masciocchi; Massimo Gallucci Journal: Radiol Med Date: 2015-07-28 Impact factor: 3.469