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Normal multiplanar movement of the spinal cord during unilateral and bilateral straight leg raise: Quantification, mechanisms, and overview
Author(s) -
Rade Marinko,
Shacklock Michael,
Könönen Mervi,
Marttila Jarkko,
Vanninen Ritva,
Kankaanpää Markku,
Airaksinen Olavi
Publication year - 2017
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.23385
Subject(s) - conus medullaris , anatomy , medicine , sagittal plane , lumbosacral joint , neuroradiology , spinal cord , radiology , magnetic resonance imaging , neurology , psychiatry
The purpose of this investigation was to provide a full set of normal data describing neural biomechanics within the vertebral canal in all three planes with unilateral and bilateral SLR tests to allow for clinical comparison with clinical cases. This is done following the notion that, due to neural continuum, tensile forces are transmitted through the lumbosacral nerve roots and dura to the conus medullaris (linear dependency principle). In this controlled radiologic study 10 asymptomatic volunteers were scanned with 1.5T magnetic resonance scanner (Siemens Magnetom Aera, Erlangen, Germany) using different scanning sequences for planning and for measurement purposes. Conus displacement in both antero‐posterior direction (sagittal slices) and lateral direction (axial slices) was quantified during unilateral passive left, right SLR, and bilateral SLR and compared with the position of the conus in the neutral (anatomic) position. It is shown that the conus medullaris displaced laterally and anteroposteriorly in response to unilateral and bilateral SLRs. Pearson's correlations were higher than 0.95 for both intra‐ and inter‐observer reliability. The observed power was higher than 0.99 for all the variables tested. Following this, the authors conclude that lateral and antero‐posterior displacement of conus medullaris into the vertebral canal occurs consistently with unilateral and bilateral SLRs following directions predicted by tension vectors. Summative information collected in this line of research in neuroradiology is here presented. We believe we have presented the first conclusive and complete full set of normal data on non‐invasive, in vivo, normative measurement of spinal cord displacement with the SLR ever presented. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1335–1342, 2017.