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Jennifer B. Massie - One of the best experts on this subject based on the ideXlab platform.
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Spinal Nerve Root compression.
Spine, 1995Co-Authors: Steven R. Garfin, Björn Rydevik, Bengt Lind, Jennifer B. MassieAbstract:The pathophysiology of sciatica is not completely understood, although our understanding of its causes is increasing. Mechanical alterations combined with inflammatory changes lead to pain. Compression alters Nerve Root conduction and compromises the nutritional support of spinal Nerve Roots (through intrinsic and extrinsic vascularity and cerebral spinal fluid percolation). Mechanical forces can lead to intraneural damage and functional changes in Nerve Roots. Chemical and metabolic effects can create an inflammatory response. Varying causes of inflammation coupled with varying degrees of compression can occur anywhere along the cauda equina or spinal Nerve Root, including the dorsal Root ganglia, and contribute to the pain response and neurologic deficits associated with sciatica.
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Straight leg raising. Anatomical effects on the spinal Nerve Root without and with fusion.
Spine, 1993Co-Authors: Stacia A. Smith, Jennifer B. Massie, Randall M. Chesnut, Steven R. GarfinAbstract:Straight leg raising (SLR) is a useful clinical test to demonstrate an inflammatory compressive process across a spinal Nerve Root. Several previous studies have attempted to evaluate the effect of SLR on Nerve Root motion, but the exact direction and amount of this motion is still unclear. Components of the SLR test that have not been adequately addressed include the effect of SLR on the intact dural-Nerve Root system, motion of the Nerve tissues as distinct from the dura, and Nerve Root strain. Separately, spinal fusion is occasionally used as an adjunct to discectomy to decrease instability and subsequent "Nerve Root irritation." The effect of a one-level fusion on in situ Nerve Root biomechanics, however, has not been evaluated. Ten fresh human cadavers underwent posterior lumbar laminectomies. Spinal Nerve Root motion was studied while a SLR maneuver was performed. Data was recorded photographically and statistically analyzed. The results were as follows: 1) SLR induced both linear motion (0.5-5 mm) and strain (2-4%) in spinal Nerves L4, L5, and S1; 2) The dura moved less than the intrathecal Nerve Root at the pedicle and experienced more strain (P < .05). 3) The Nerve Roots moved laterally toward the pedicle and thus would move into a posterolaterally herniated disc. 4) Rigid anterior stabilization did not decrease Nerve Root motion or strain.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
Björn Rydevik - One of the best experts on this subject based on the ideXlab platform.
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Spinal Nerve Root compression.
Spine, 1995Co-Authors: Steven R. Garfin, Björn Rydevik, Bengt Lind, Jennifer B. MassieAbstract:The pathophysiology of sciatica is not completely understood, although our understanding of its causes is increasing. Mechanical alterations combined with inflammatory changes lead to pain. Compression alters Nerve Root conduction and compromises the nutritional support of spinal Nerve Roots (through intrinsic and extrinsic vascularity and cerebral spinal fluid percolation). Mechanical forces can lead to intraneural damage and functional changes in Nerve Roots. Chemical and metabolic effects can create an inflammatory response. Varying causes of inflammation coupled with varying degrees of compression can occur anywhere along the cauda equina or spinal Nerve Root, including the dorsal Root ganglia, and contribute to the pain response and neurologic deficits associated with sciatica.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
Steven R. Garfin - One of the best experts on this subject based on the ideXlab platform.
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Spinal Nerve Root compression.
Spine, 1995Co-Authors: Steven R. Garfin, Björn Rydevik, Bengt Lind, Jennifer B. MassieAbstract:The pathophysiology of sciatica is not completely understood, although our understanding of its causes is increasing. Mechanical alterations combined with inflammatory changes lead to pain. Compression alters Nerve Root conduction and compromises the nutritional support of spinal Nerve Roots (through intrinsic and extrinsic vascularity and cerebral spinal fluid percolation). Mechanical forces can lead to intraneural damage and functional changes in Nerve Roots. Chemical and metabolic effects can create an inflammatory response. Varying causes of inflammation coupled with varying degrees of compression can occur anywhere along the cauda equina or spinal Nerve Root, including the dorsal Root ganglia, and contribute to the pain response and neurologic deficits associated with sciatica.
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Straight leg raising. Anatomical effects on the spinal Nerve Root without and with fusion.
Spine, 1993Co-Authors: Stacia A. Smith, Jennifer B. Massie, Randall M. Chesnut, Steven R. GarfinAbstract:Straight leg raising (SLR) is a useful clinical test to demonstrate an inflammatory compressive process across a spinal Nerve Root. Several previous studies have attempted to evaluate the effect of SLR on Nerve Root motion, but the exact direction and amount of this motion is still unclear. Components of the SLR test that have not been adequately addressed include the effect of SLR on the intact dural-Nerve Root system, motion of the Nerve tissues as distinct from the dura, and Nerve Root strain. Separately, spinal fusion is occasionally used as an adjunct to discectomy to decrease instability and subsequent "Nerve Root irritation." The effect of a one-level fusion on in situ Nerve Root biomechanics, however, has not been evaluated. Ten fresh human cadavers underwent posterior lumbar laminectomies. Spinal Nerve Root motion was studied while a SLR maneuver was performed. Data was recorded photographically and statistically analyzed. The results were as follows: 1) SLR induced both linear motion (0.5-5 mm) and strain (2-4%) in spinal Nerves L4, L5, and S1; 2) The dura moved less than the intrathecal Nerve Root at the pedicle and experienced more strain (P < .05). 3) The Nerve Roots moved laterally toward the pedicle and thus would move into a posterolaterally herniated disc. 4) Rigid anterior stabilization did not decrease Nerve Root motion or strain.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
Jose De Andres - One of the best experts on this subject based on the ideXlab platform.
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Morphologic study of Nerve Root and types of needle used in transforaminal injections.
Regional anesthesia and pain medicine, 2011Co-Authors: José M. Hernández-garcía, Miguel Angel Reina, Alberto Prats-galino, Jose De AndresAbstract:Background: The bevel type and location of the distal orifice of the needle may have relevance for potential complications occurring during transforaminal epidural injection. Methods: We examined by scanning electron microscopy the structural aspects of spinal Nerve Root cuffs of 3 human cadavers, and 3 needle types used in transforaminal injections: 22-gauge Quincke spinal needles, 22-gauge blunt Nerve block needles, and 20-gauge radiofrequency blunt needles. We made punctures in vitro in the spinal Nerve Root cuffs, and we studied the structures affected. Results: There is fat tissue within the Nerve Root with irregular distribution. In needles with a round tip, the distal orifice maintained an extraneural location after puncture of the Nerve Root cuff. The length of the needle required to introduce the distal orifice completely inside the Nerve Root cuff was variable, depending on the type: shortest for a Quincke needle (1.8 mm), 4.1 mm for the Epimed, and longest for radiofrequency needles (5.7 mm). Conclusions: The layer of fat around Nerve Roots may prevent the contact of the needle tip with axons. The sharp needle tip entered the Nerve Root cuff more easily than the blunt tip in the cadaveric Nerve Root samples, measured in a qualitative manner. There is a need for clinical studies to ascertain if blunt needles may be safer than sharp needles for transforaminal injections.
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the ultrastructure of the human spinal Nerve Root cuff in the lumbar spine
Anesthesia & Analgesia, 2008Co-Authors: Miguel Angel Reina, M C Villanueva, Ana Carrera, Fabiola Machés, A Lopez, Jose De AndresAbstract:BACKGROUND: Spinal Nerve Root cuffs may be relevant in selective Nerve Root and epidural blockade. METHODS: We examined the ultrastructural aspects of spinal Nerve Root cuffs, such as their cellular and fibrillar components, using special histological staining methods, transmission and scanning electron microscopy, from six human cadavers. RESULTS: The morphology of the spinal Nerve Root cuff resembles that of the spinal subdural compartment. Cells gather together in compact layers due to specialized junctions. The thickness of its cellular layers is 5 to 8 microns; cells appear oriented parallel to the direction of their own Nerve Roots. The fibrillar component, made largely of collagen fibers, is found in the outer part of the spinal Nerve Root cuff and measures 100 to 150 microns. Numerous adipocytes separate dural laminas in concentric layers, extending from the dural sac to the spinal Nerve Root ganglia. However, adipocytes are not found within the thickness of the dural sac. CONCLUSIONS: The presence of few capillaries and the short distance between fat and axons may affect the passage of epidurally injected substances towards Nerve Root axons.
Robert A Pedowitz - One of the best experts on this subject based on the ideXlab platform.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
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Effects of magnitude and duration of compression on spinal Nerve Root conduction.
Spine, 1992Co-Authors: Robert A Pedowitz, Jennifer B. Massie, Robert R. Myers, Steven R. Garfin, Michael R Swenson, Alan R. Hargens, Björn RydevikAbstract:: Spinal Nerve Root compression occurs commonly in conditions such as herniated nucleus pulposus, spinal stenosis, and trauma. However, the pathophysiology of the symptoms and signs related to spinal Nerve Root compression is poorly understood. The purpose of the present study was to assess and compare effects of various pressures and durations of acute compression on spinal Nerve Root conduction in the pig cauda equina. Efferent conduction (compound motor action potentials) and afferent conduction (compound Nerve action potentials) were monitored during compression for 2 or 4 hours with compression pressures of 0 (sham), 50, 100, or 200 mm Hg. Recovery from compression was monitored for 1.5 hours. No significant deficits in spinal Nerve Root conduction were observed with 0 or 50 mm Hg compression, compared to significant conduction deficits induced by 100 and 200 mm Hg compression. Three-way analysis of variance demonstrated significant effects of compression pressure and duration on conduction at the end of compression and recovery, with a significant difference between efferent and afferent conduction at the end of the recovery period. These observations suggest an interaction between biomechanical and microvascular mechanisms in the production of Nerve Root conduction deficits. Such information may relate to the motor and sensory dysfunction in clinical conditions associated with spinal Nerve Root compression.
