Two great studies on the mobility of the spinal cord during neural tension testing. Spine (Phila Pa 1976). 2014 Jul 15;39(16):1288-93. doi: 10.1097/BRS.0000000000000263. 2014 young investigator award winner: in vivo magnetic resonance imaging measurement of spinal cord displacement in the thoracolumbar region of asymptomatic subjects: part 1: straight leg raise test. Rade M1, Könönen M, Vanninen R, Marttila J, Shacklock M, Kankaanpää M, Airaksinen O. Author information Abstract STUDY DESIGN: Controlled radiological study. OBJECTIVE: To investigate noninvasively in vivo spinal cord displacement in the vertebral canal during the passive straight leg raise (SLR) in asymptomatic subjects. The basic assumption is that the cord follows L5 and S1 nerve roots displacement by similar magnitude and direction (principle of linear dependence). SUMMARY OF BACKGROUND DATA: It is generally accepted that the SLR produces some caudal movement mainly of L5 and S1 nerve roots, but the magnitude of this displacement is still a matter of debate. METHODS: Sixteen asymptomatic volunteers were scanned with 1.5-T magnetic resonance scanner (Siemens Avanto, Erlangen, Germany) using T2-weighted turbo spin-echo fat-saturation sequence.The displacement of the medullar cone relative to the vertebral endplate of the adjacent vertebra during the passive SLR was quantified and compared with the position of the conus in the neutral (anatomic) position. Each movement was performed twice for evaluation of reproducibility. The measurements were repeated by 2 observers. Four practitioners performed the maneuvers in a random sequence to avoid series effects. RESULTS: Compared with the neutral (anatomic) position, the medullar cone displaced caudally in the spinal canal by 2.31 ± 1.2 mm with right (P ≤ 0.001) and 2.35 ± 1.2 mm with left SLR (P ≤ 0.001).Spearman correlations proved higher than 0.99 for intra and interobserver reliability, as well as results reproducibility testing for each maneuver. CONCLUSION: The data show that the spinal cord in the thoracolumbar region slides distally in response to the clinically applied SLR test. The high correlation values in this study show that these movements are consistent and reproducible. Because of the neural continuum, the authors speculate that this movement might be directly proportional to the sliding of the L5 and S1 neural roots.This study offers baseline measurements on which further studies in diagnosis of lumbar disc protrusion and radiculopathy may be developed.Level of Evidence: 5. PMID: 24503693 Spine (Phila Pa 1976). 2014 Jul 15;39(16):1294-300. doi: 10.1097/BRS.0000000000000264. 2014 young investigator award winner: in vivo magnetic resonance imaging measurement of spinal cord displacement in the thoracolumbar region of asymptomatic subjects: part 2: comparison between unilateral and bilateral straight leg raise tests. Rade M1, Könönen M, Vanninen R, Marttila J, Shacklock M, Kankaanpää M, Airaksinen O. Author information Abstract STUDY DESIGN: Controlled radiological study. OBJECTIVE: Ascertain if a difference exists in the mechanical effects on the cord between the unilateral and bilateral straight leg raise (SLR) and to verify whether the effect on the spinal cord may be cumulative between the two. SUMMARY OF BACKGROUND DATA: To the authors knowledge these are the first data on noninvasive, in vivo, normative measurement of spinal cord displacement with bilateral SLR test. METHODS: Sixteen asymptomatic volunteers were scanned with 1.5-T magnetic resonance scanner (Siemens Avanto, Erlangen, Germany) using T2-weighted turbo spin-echo fat-saturation sequence.The displacement of the medullar cone relative to the vertebral endplate of the adjacent vertebra during the passive bilateral SLR was quantified and compared with the position of the conus in the neutral (anatomic) position and with unilateral SLR. Each movement was performed twice for evaluation of reproducibility. The measurements were repeated by 2 observers. Four practitioners performed the maneuvers in a random sequence to avoid series effects. RESULTS: Compared with the neutral (anatomic) position, the medullar cone displaced caudally in the spinal canal by 2.33 ± 1.2 mm (μ ± SD) with unilateral (P ≤ 0.001) and 4.58 ± 1.48 mm with bilateral SLR (P ≤ 0.001). Statistical significance was also reached for bilateral versus unilateral SLR (P ≤ 0.001).Spearman correlations proved higher than 0.99 for intra and interobserver reliability, and 0.984 for results reproducibility in bilateral SLR. CONCLUSION: The caudal displacement of the medullar cone was significantly greater (almost double) with the bilateral SLR than the unilateral SLR. We hypothesize that this greater movement may be because more force was transmitted to the cord through a larger number nerve roots with the bilateral than unilateral SLR.The high correlation values in this study show that these movements are consistent and reproducible.This study offers baseline measurements on which further studies in diagnosis and treatment of lumbar disc protrusion and radiculopathy may be developed.Level of Evidence: 5. PMID: 24503694
Posted on: Mon, 14 Jul 2014 16:34:03 +0000
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