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Soltan N, Siegmund GP, Cripton PA, Jones CF. Geometric and Inertial Properties of the Pig Head and Brain in an Anatomical Coordinate System. Ann Biomed Eng 2023; 51:2544-2553. [PMID: 37358713 PMCID: PMC10598157 DOI: 10.1007/s10439-023-03294-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/19/2023] [Indexed: 06/27/2023]
Abstract
Porcine models in injury biomechanics research often involve measuring head or brain kinematics. Translation of data from porcine models to other biomechanical models requires geometric and inertial properties of the pig head and brain, and a translationally relevant anatomical coordinate system (ACS). In this study, the head and brain mass, center of mass (CoM), and mass moments of inertia (MoI) were characterized, and an ACS was proposed for the pre-adolescent domestic pig. Density-calibrated computed tomography scans were obtained for the heads of eleven Large White × Landrace pigs (18-48 kg) and were segmented. An ACS with a porcine-equivalent Frankfort plane was defined using externally palpable landmarks (right/left frontal process of the zygomatic bone and zygomatic process of the frontal bone). The head and brain constituted 7.80 ± 0.79% and 0.33 ± 0.08% of the body mass, respectively. The head and brain CoMs were primarily ventral and caudal to the ACS origin, respectively. The mean head and brain principal MoI (in the ACS with origin at respective CoM) ranged from 61.7 to 109.7 kg cm2, and 0.2 to 0.6 kg cm2, respectively. These data may aid the comparison of head and brain kinematics/kinetics data and the translation between porcine and human injury models.
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Affiliation(s)
- Nikoo Soltan
- Department of Mechanical Engineering, The University of British Columbia, Vancouver, BC Canada
- Orthopaedic and Injury Biomechanics Group, ICORD, Vancouver, BC Canada
| | - Gunter P. Siegmund
- MEA Forensic Engineers & Scientists, Laguna Hills, CA USA
- School of Kinesiology, The University of British Columbia, Vancouver, BC Canada
| | - Peter A. Cripton
- Department of Mechanical Engineering, The University of British Columbia, Vancouver, BC Canada
- Orthopaedic and Injury Biomechanics Group, ICORD, Vancouver, BC Canada
- School of Biomedical Engineering, The University of British Columbia, Vancouver, BC Canada
| | - Claire F. Jones
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, SA Australia
- Adelaide Spinal Research Group, Centre for Orthopaedic & Trauma Research, The University of Adelaide, Adelaide, SA Australia
- Department of Orthopaedics & Trauma, Royal Adelaide Hospital, Adelaide, SA Australia
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2
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Yao HD, Svensson MY, Nilsson H. Deformation of dorsal root ganglion due to pressure transients of venous blood and cerebrospinal fluid in the cervical vertebral canal. J Biomech 2018; 76:16-26. [PMID: 29801662 DOI: 10.1016/j.jbiomech.2018.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/26/2018] [Accepted: 05/07/2018] [Indexed: 11/17/2022]
Abstract
The dorsal root ganglion (DRG) that is embedded in the foramen of the cervical vertebra can be injured during a whiplash motion. A potential cause is that whilst the neck bends in the whiplash motion, the changes of spinal canal volume induce impulsive pressure transients in the venous blood outside the dura mater (DM) and in the cerebrospinal fluid (CSF) inside the DM. The fluids can dynamically interact with the DRG and DM, which are deformable. In this work, the interaction is investigated numerically using a strong-coupling partitioned method that synchronize the computations of the fluid and structure. It is found that the interaction includes two basic processes, i.e., the pulling and pressing processes. In the pulling process, the DRG is stretched towards the spinal canal, and the venous blood is driven into the canal via the foramen. This process results from negative pressure in the fluids. In contrast, the pressing process is caused by positive pressure that leads to compression of the DRG and the outflow of the venous blood from the canal. The largest pressure gradient is observed at the foramen, where the DRG is located at. The DRG is subject to prominent von Mises stress near its end, which is fixed without motions. The negative internal pressure is more efficient to deform the DRG than the positive internal pressure. This indicates that the most hazardous condition for the DRG is the pulling process.
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Affiliation(s)
- Hua-Dong Yao
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
| | - Mats Y Svensson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; SAFER Vehicle and Traffic Safety Centre, Chalmers University of Technology, Sweden
| | - Håkan Nilsson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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Yao HD, Svensson MY, Nilsson H. Transient pressure changes in the vertebral canal during whiplash motion--A hydrodynamic modeling approach. J Biomech 2016; 49:416-22. [PMID: 26827171 DOI: 10.1016/j.jbiomech.2016.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 11/17/2022]
Abstract
In vehicle collisions, the occupant's torso is accelerated in a given direction while the unsupported head tends to lag behind. This mechanism results in whiplash motion to the neck. In whiplash experiments conducted for animals, pressure transients have been recorded in the spinal canal. It was hypothesized that the transients caused dorsal root ganglion dysfunction. Neck motion introduces volume changes inside the vertebral canal. The changes require an adaptation which is likely achieved by redistribution of blood volume in the internal vertebral venous plexus (IVVP). Pressure transients then arise from the rapid redistribution. The present study aimed to explore the hypothesis theoretically and analytically. Further, the objectives were to quantify the effect of the neck motion on the pressure generation and to identify the physical factors involved. We developed a hydrodynamic system of tubes that represent the IVVP and its lateral intervertebral vein connections. An analytical model was developed for an anatomical geometrical relation that the venous blood volume changes with respect to the vertebral angular displacement. This model was adopted in the hydrodynamic tube system so that the system can predict the pressure transients on the basis of the neck vertebral motion data from a whiplash experiment. The predicted pressure transients were in good agreement with the earlier experimental data. A parametric study was conducted and showed that the system can be used to assess the influences of anatomical geometrical properties and vehicle collision severity on the pressure generation.
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Affiliation(s)
- Hua-Dong Yao
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
| | - Mats Y Svensson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Håkan Nilsson
- Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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Zhang S, Nicholson KJ, Smith JR, Gilliland TM, Syré PP, Winkelstein BA. The roles of mechanical compression and chemical irritation in regulating spinal neuronal signaling in painful cervical nerve root injury. STAPP CAR CRASH JOURNAL 2013; 57:219-242. [PMID: 24435733 DOI: 10.4271/2013-22-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Both traumatic and slow-onset disc herniation can directly compress and/or chemically irritate cervical nerve roots, and both types of root injury elicit pain in animal models of radiculopathy. This study investigated the relative contributions of mechanical compression and chemical irritation of the nerve root to spinal regulation of neuronal activity using several outcomes. Modifications of two proteins known to regulate neurotransmission in the spinal cord, the neuropeptide calcitonin gene-related peptide (CGRP) and glutamate transporter 1 (GLT-1), were assessed in a rat model after painful cervical nerve root injuries using a mechanical compression, chemical irritation or their combination of injury. Only injuries with compression induced sustained behavioral hypersensitivity (p≤0.05) for two weeks and significant decreases (p<0.037) in CGRP and GLT-1 immunoreactivity to nearly half that of sham levels in the superficial dorsal horn. Because modification of spinal CGRP and GLT-1 is associated with enhanced excitatory signaling in the spinal cord, a second study evaluated the electrophysiological properties of neurons in the superficial and deeper dorsal horn at day 7 after a painful root compression. The evoked firing rate was significantly increased (p=0.045) after compression and only in the deeper lamina. The painful compression also induced a significant (p=0.002) shift in the percentage of neurons in the superficial lamina classified as low- threshold mechanoreceptive (sham 38%; compression 10%) to those classified as wide dynamic range neurons (sham 43%; compression 74%). Together, these studies highlight mechanical compression as a key modulator of spinal neuronal signaling in the context of radicular injury and pain.
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Affiliation(s)
- Sijia Zhang
- Department of Bioengineering, University of Pennsylvania
| | | | - Jenell R Smith
- Department of Bioengineering, University of Pennsylvania
| | | | - Peter P Syré
- Department of Neurosurgery, University of Pennsylvania
| | - Beth A Winkelstein
- Departments of Bioengineering and Neurosurgery, University of Pennsylvania
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Morishita Y, Maeda T, Ueta T, Naito M, Shiba K. Dynamic somatosensory evoked potentials to determine electrophysiological effects on the spinal cord during cervical spine extension. J Neurosurg Spine 2013; 19:288-92. [DOI: 10.3171/2013.5.spine12933] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The goal of this prospective study was to investigate somatosensory evoked potentials (SSEPs) during dynamic motion of the cervical spine and to evaluate the efficacy of analyzing dynamic SSEPs for predicting dynamic effects on the spinal cord in patients with cervical spondylotic myelopathy (CSM).
Methods
In total, 40 human subjects (20 CSM patients and 20 healthy volunteers as a control group) were examined prospectively using dynamic SSEPs with median nerve stimulation. The CSM patients showed cervical myelopathy due to cervical cord compression at the C4–5 segment. The SSEPs were examined with the cervical spine in a neutral position and at a 20° extension for 10 and 20 minutes. Changes in the N20 latency and amplitude were determined and analyzed. The authors defined the changes in the N20 latency and N20 amplitude between the neutral and extension positions of the cervical spine as percent latency and amplitude, respectively.
Results
In the CSM patients, SSEPs tended to deteriorate after cervical spine extension, and a statistically significant deterioration of the N20 amplitude after the extension was observed. Moreover, the percent latency and amplitude progressively increased during cervical spine extension in these patients. In the healthy controls, SSEPs tended to deteriorate with cervical spine extension, but these changes did not result in statistically significant differences. Moreover, in this group the percent latency and amplitude were almost identical during the extension. When the CSM patients and the healthy controls were compared, a significant difference in the percent amplitude was observed between the 2 groups during the cervical spine extension.
Conclusions
This study suggests the potential of dynamic SSEPs as a useful neurophysiological technique to detect the effect of dynamic factors on the pathogenesis of CSM.
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Affiliation(s)
| | - Takeshi Maeda
- 1Department of Orthopedic Surgery, Spinal Injuries Center, Iizuka; and
| | - Takayoshi Ueta
- 1Department of Orthopedic Surgery, Spinal Injuries Center, Iizuka; and
| | - Masatoshi Naito
- 2Department of Orthopedic Surgery, Fukuoka University, Fukuoka, Japan
| | - Keiichiro Shiba
- 1Department of Orthopedic Surgery, Spinal Injuries Center, Iizuka; and
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Chien A, Sterling M. Central hypersensitivity in whiplash: implications for physiotherapy assessment and management. PHYSICAL THERAPY REVIEWS 2013. [DOI: 10.1179/108331905x68574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Gales N, Kunz SN, Rocksén D, Arborelius UP, Svensson MY, Hell W, Schick S. Muscle pathologies after cervical spine distortion-like exposure--a porcine model. TRAFFIC INJURY PREVENTION 2013; 14:828-834. [PMID: 24073771 DOI: 10.1080/15389588.2013.773400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE Histological evaluation of porcine posterior cervical muscles after a forceful translational and extensional head retraction simulating high-speed rear end impact. METHODS Four anesthetized pigs were exposed to a cervical spine distortion (CSD)-like motion in a lying position. After 2 different survival times of 4 and 6 h (posttrauma), the pigs were euthanized and tissue sampling of posterior cervical muscles was performed. A standard histological staining method involving paraffin-embedded sections was used to analyze the muscles, focusing on injury signs like hemorrhage and inflammatory cell reaction. A pig that was not subjected to impact was used as a control pig and was subjected to the same procedure to exclude any potential artifacts from the autopsy. RESULTS The differentiation of 8 different posterior neck muscles in the dissection process was successful in more than 50 percent for each muscle of interest. Staining and valid analysis was possible from all extracted samples. Muscle injuries to the deepest posterior neck muscles could be found, especially in the musculus obliquus samples, which showed laminar bleedings in 4 out of 4 samples. In addition, in 4 out of 4 samples we were able to see increased cellular reactions. The splenius muscle also showed bleeding in all 4 samples. All animals showed muscle injury signs in more than three quarters of analyzed neck muscles. Differences between survival times of 4 and 6 h in terms of muscular injury were not of primary interest and could not be found. CONCLUSIONS By simulating a CSD-like motion we were able to confirm injuries in the posterior cervical muscles under severe loading conditions. Further studies need to be conducted to determine whether these muscle injuries also occur under lower exposure forces.
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Affiliation(s)
- N Gales
- a Institute for Legal Medicine, Department of Accident Research , Ludwig-Maximilians-University , Munich , Germany
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Davis CG. Mechanisms of chronic pain from whiplash injury. J Forensic Leg Med 2012; 20:74-85. [PMID: 23357391 DOI: 10.1016/j.jflm.2012.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 05/03/2012] [Accepted: 05/30/2012] [Indexed: 10/28/2022]
Abstract
This article is to provide insights into the mechanisms underlying chronic pain from whiplash injury. Studies show that injury produces plasticity changes of different neuronal structures that are responsible for amplification of nociception and exaggerated pain responses. There is consistent evidence for hypersensitivity of the central nervous system to sensory stimulation in chronic pain after whiplash injury. Tissue damage, detected or not by the available diagnostic methods, is probably the main determinant of central hypersensitivity. Different mechanisms underlie and co-exist in the chronic whiplash condition. Spinal cord hyperexcitability in patients with chronic pain after whiplash injury can cause exaggerated pain following low intensity nociceptive or innocuous peripheral stimulation. Spinal hypersensitivity may explain pain in the absence of detectable tissue damage. Whiplash is a heterogeneous condition with some individuals showing features suggestive of neuropathic pain. A predominantly neuropathic pain component is related to a higher pain/disability level.
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Jones CF, Lee JHT, Kwon BK, Cripton PA. Development of a large-animal model to measure dynamic cerebrospinal fluid pressure during spinal cord injury. J Neurosurg Spine 2012; 16:624-35. [DOI: 10.3171/2012.3.spine11970] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Spinal cord injury (SCI) often results in considerable permanent neurological impairment, and unfortunately, the successful translation of effective treatments from laboratory models to human patients is lacking. This may be partially attributed to differences in anatomy, physiology, and scale between humans and rodent models. One potentially important difference between the rodent and human spinal cord is the presence of a significant CSF volume within the intrathecal space around the human cord. While the CSF may “cushion” the spinal cord, pressure waves within the CSF at the time of injury may contribute to the extent and severity of the primary injury. The objective of this study was to develop a model of contusion SCI in a miniature pig and establish the feasibility of measuring spinal CSF pressure during injury.
Methods
A custom weight-drop device was used to apply thoracic contusion SCI to 17 Yucatan miniature pigs. Impact load and velocity were measured. Using fiber optic pressure transducers implanted in the thecal sac, CSF pressures resulting from 2 injury severities (caused by 50-g and 100-g weights released from a 50-cm height) were measured.
Results
The median peak impact loads were 54 N and 132 N for the 50-g and 100-g injuries, respectively. At a nominal 100 mm from the injury epicenter, the authors observed a small negative pressure peak (median −4.6 mm Hg [cranial] and −5.8 mm Hg [caudal] for 50 g; −27.6 mm Hg [cranial] and −27.2 mm Hg [caudal] for 100 g) followed by a larger positive pressure peak (median 110.5 mm Hg [cranial] and 77.1 mm Hg [caudal] for 50 g; 88.4 mm Hg [cranial] and 67.2 mm Hg [caudal] for 100 g) relative to the preinjury pressure. There were no significant differences in peak pressure between the 2 injury severities or the caudal and cranial transducer locations.
Conclusions
A new model of contusion SCI was developed to measure spinal CSF pressures during the SCI event. The results suggest that the Yucatan miniature pig is an appropriate model for studying CSF, spinal cord, and dura interactions during injury. With further development and characterization it may be an appropriate in vivo largeanimal model of SCI to answer questions regarding pathological changes, therapeutic safety, or treatment efficacy, particularly where humanlike dimensions and physiology are important.
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Affiliation(s)
- Claire F. Jones
- 1Orthopaedic and Injury Biomechanics Laboratory, Departments of Mechanical Engineering and Orthopaedics,
- 2International Collaboration on Repair Discoveries, and
| | - Jae H. T. Lee
- 2International Collaboration on Repair Discoveries, and
| | - Brian K. Kwon
- 2International Collaboration on Repair Discoveries, and
- 3Combined Neurosurgical and Orthopaedic Spine Program, Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter A. Cripton
- 1Orthopaedic and Injury Biomechanics Laboratory, Departments of Mechanical Engineering and Orthopaedics,
- 2International Collaboration on Repair Discoveries, and
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Cervical status after neck sprains in frontal and rear-end car impacts. Injury 2012; 43:423-30. [PMID: 21683356 DOI: 10.1016/j.injury.2011.05.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 05/19/2011] [Accepted: 05/19/2011] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare the cervical status after neck sprains in frontal and rear-end car impacts with respect to earlier proposed neck-sprain injury mechanisms, rotated head at impact, and the seat-belt geometry. METHODS A prospective, multidisciplinary, in-depth study was made based on 23 car occupants injured in frontal impacts and 108 injured in rear-end impacts. The active neck mobility was measured in protraction-retraction, flexion-extension, side bending right-left, and rotation right-left. This was done in the acute phase and then three and twelve months later. The maximum range, increase in pain, and level of pain were recorded for each movement. A subgroup with increased pain during movements towards the impact direction, but not in the opposite one, so-called isolated contra-directional pain (ICP), was further analysed. The side bending and rotation mobility were studied in another subgroup, in which the head was rotated inwards or outwards relative the car, i.e. away from or towards the diagonal part of the seat belt. RESULTS Rear-end impacts more often than frontal impacts caused greater restrictions of the cervical mobility and more frequently increased pain at the three different times that measurements were recorded, but, with few exceptions, the differences for each movement were not statistically significant. Increased pain during extension was more often noted after rear-end impacts. ICP during pro-/retraction was also more often noted after rear-end impacts. Head-inward rotation in rear-end impacts caused a more restricted mobility in the same direction at the primary examination than head-outward rotation. CONCLUSIONS The cervical status after neck sprains in frontal and rear-end car impacts is very similar, and the cervical range of movement in different directions and increased pain during cervical motions do not reveal any specific isolated injury mechanisms. Combined injury mechanisms should be considered, and further studies are recommended to investigate asymmetric loading during impact.
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Ivancic PC. Cervical neural space narrowing during simulated rear crashes with anti-whiplash systems. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2012; 21:879-86. [PMID: 22270248 DOI: 10.1007/s00586-012-2159-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 01/03/2012] [Accepted: 01/11/2012] [Indexed: 10/14/2022]
Abstract
PURPOSE Chronic radicular symptoms have been documented in whiplash patients, potentially caused by cervical neural tissue compression during an automobile rear crash. Our goals were to determine neural space narrowing of the lower cervical spine during simulated rear crashes with whiplash protection system (WHIPS) and active head restraint (AHR) and to compare these data to those obtained with no head restraint (NHR). We extrapolated our results to determine the potential for cord, ganglion, and nerve root compression. METHODS Our model, consisting of a human neck specimen within a BioRID II crash dummy, was subjected to simulated rear crashes in a WHIPS seat (n = 6, peak 12.0 g and ΔV 11.4 kph) or AHR seat and subsequently with NHR (n = 6, peak 11.0 g and ΔV 10.2 kph with AHR; peak 11.5 g and ΔV 10.7 kph with NHR). Cervical canal and foraminal narrowing were computed and average peak values statistically compared (P < 0.05) between WHIPS, AHR, and NHR. RESULTS Average peak canal and foramen narrowing could not be statistically differentiated between WHIPS, AHR, or NHR. Peak narrowing with WHIPS or AHR was 2.7 mm for canal diameter and 1.6 mm, 2.7 mm, and 5.9 mm(2) for foraminal width, height and area, respectively. CONCLUSIONS While lower cervical spine cord compression during a rear crash is unlikely in those with normal canal diameters, our results demonstrated foraminal kinematics sufficient to compress spinal ganglia and nerve roots. Future anti-whiplash systems designed to reduce cervical neural space narrowing may lead to reduced radicular symptoms in whiplash patients.
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Affiliation(s)
- Paul C Ivancic
- Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, 333 Cedar St, P.O. Box 208071, New Haven, CT 06520-8071, USA.
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Budgell BS, Bolton PS. Cerebrospinal Fluid Pressure Response to Upper Cervical Vertebral Motion and Displacement in the Anesthetized Rat. J Manipulative Physiol Ther 2010; 33:355-61. [DOI: 10.1016/j.jmpt.2010.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 03/26/2010] [Accepted: 04/06/2010] [Indexed: 11/27/2022]
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Rothman SM, Nicholson KJ, Winkelstein BA. Time-Dependent Mechanics and Measures of Glial Activation and Behavioral Sensitivity in a Rodent Model of Radiculopathy. J Neurotrauma 2010; 27:803-14. [DOI: 10.1089/neu.2009.1045] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Sarah M. Rothman
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kristen J. Nicholson
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Beth A. Winkelstein
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania
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Láinez MJA, Piera A, Bono G. Headache attributed to head or neck trauma. HANDBOOK OF CLINICAL NEUROLOGY 2010; 97:501-516. [PMID: 20816452 DOI: 10.1016/s0072-9752(10)97046-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- Miguel J A Láinez
- Department of Neurology, Hospital Clínic University, University of Valencia, Valencia, Spain.
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15
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Siegmund GP, Winkelstein BA, Ivancic PC, Svensson MY, Vasavada A. The anatomy and biomechanics of acute and chronic whiplash injury. TRAFFIC INJURY PREVENTION 2009; 10:101-112. [PMID: 19333822 DOI: 10.1080/15389580802593269] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Whiplash injury is the most common motor vehicle injury, yet it is also one of the most poorly understood. Here we examine the evidence supporting an organic basis for acute and chronic whiplash injuries and review the anatomical sites within the neck that are potentially injured during these collisions. For each proposed anatomical site--facet joints, spinal ligaments, intervertebral discs, vertebral arteries, dorsal root ganglia, and neck muscles--we present the clinical evidence supporting that injury site, its relevant anatomy, the mechanism of and tolerance to injury, and the future research needed to determine whether that site is responsible for some whiplash injuries. This article serves as a snapshot of the current state of whiplash biomechanics research and provides a roadmap for future research to better understand and ultimately prevent whiplash injuries.
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Affiliation(s)
- Gunter P Siegmund
- MEA Forensic Engineers & Scientists, 11-11151 Horseshoe Way, Richmond, BC, Canada.
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Chien A, Eliav E, Sterling M. Hypoaesthesia occurs with sensory hypersensitivity in chronic whiplash – Further evidence of a neuropathic condition. ACTA ACUST UNITED AC 2009; 14:138-46. [DOI: 10.1016/j.math.2007.12.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 11/08/2007] [Accepted: 12/21/2007] [Indexed: 11/26/2022]
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17
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Sterling M. Balancing the ‘bio’ with the psychosocial in whiplash associated disorders. ACTA ACUST UNITED AC 2006; 11:180-1. [PMID: 16574464 DOI: 10.1016/j.math.2006.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 12/23/2005] [Accepted: 02/03/2006] [Indexed: 11/26/2022]
Affiliation(s)
- Michele Sterling
- Division of Physiotherapy, The University of Queensland, St Lucia 4072, Australia.
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Chen C, Lu Y, Kallakuri S, Patwardhan A, Cavanaugh JM. Distribution of A-delta and C-fiber receptors in the cervical facet joint capsule and their response to stretch. J Bone Joint Surg Am 2006; 88:1807-16. [PMID: 16882906 DOI: 10.2106/jbjs.e.00880] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND It has been proposed that cervical facet joint capsules are a major source of whiplash pain. However, there is a paucity of neurophysiologic data to support this hypothesis. The purposes of this study were to determine the distribution of A-delta and C-fiber sensory receptors in the facet joint capsule and to test their patterns of response to stretch and related sensory function. METHODS Laminectomy from C4 to C7 was performed in seventeen goats, while they were under general anesthesia, to expose the C6 nerve roots. Customized dual bipolar electrodes were used to record neural activity from one of the C6 branches. An 8 or 15-V electrical stimulus was used to provoke receptor activity in nine designated areas on the dorsal part of the C5-C6 facet joint capsule. Receptors were classified on the basis of conduction velocities. The waveform of an identified receptor was set up as a template to determine its neural activity in response to capsular stretch. The characteristics of each single receptor's response to capsular stretch were analyzed to determine its sensory function as a mechanoreceptor or nociceptor. RESULTS Two hundred and forty-eight receptors on the dorsal part of the C5-C6 facet joint capsule were evoked by electrical stimulation in the seventeen goats. More C-fiber receptors were found on the dorsolateral aspect of the facet joint capsule, where tendons and muscles were attached. The response to stretch of 120 receptors, from twelve goats, were analyzed to classify them into one of four categories (high-threshold mechanoreceptors, non-saturated low-threshold mechanoreceptors, saturated low-threshold mechanoreceptors, and silent receptors) or as unclassified receptors. CONCLUSIONS The existence of receptors in the facet joint capsule indicates that the capsule has pain and proprioceptive sensory functions.
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Affiliation(s)
- Chaoyang Chen
- Bioengineering Center, Wayne State University, 818 West Hancock Avenue, Detroit, MI 48202, USA.
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Tominaga Y, Maak TG, Ivancic PC, Panjabi MM, Cunningham BW. Head-turned rear impact causing dynamic cervical intervertebral foramen narrowing: implications for ganglion and nerve root injury. J Neurosurg Spine 2006; 4:380-7. [PMID: 16703905 DOI: 10.3171/spi.2006.4.5.380] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT A rotated head posture at the time of vehicular rear impact has been correlated with a higher incidence and greater severity of chronic radicular symptoms than accidents occurring with the occupant facing forward. No studies have been conducted to quantify the dynamic changes in foramen dimensions during head-turned rear-impact collisions. The objectives of this study were to quantify the changes in foraminal width, height, and area during head-turned rear-impact collisions and to determine if dynamic narrowing causes potential cervical nerve root or ganglion impingement. METHODS The authors subjected a whole cervical spine model with muscle force replication and a surrogate head to simulated head-turned rear impacts of 3.5, 5, 6.5, and 8 G following a noninjurious 2-G baseline acceleration. Continuous dynamic foraminal width, height, and area narrowing were recorded, and peaks were determined during each impact; these data were then statistically compared with those obtained at baseline. The authors observed significant increases (p < 0.05) in mean peak foraminal width narrowing values greater than baseline values, of up to 1.8 mm in the left C5-6 foramen at 8 G. At the right C2-3 foramen, the mean peak dynamic foraminal height was significantly narrower than baseline when subjected to rear-impacts of 5 and 6.5 G, but no significant increases in foraminal area were observed. Analysis of the results indicated that the greatest potential for cervical ganglion compression injury existed at C5-6 and C6-7. Greater potential for ganglion compression injury existed at C3-4 and C4-5 during head-turned rear impact than during head-forward rear impact. CONCLUSIONS Extrapolation of present results indicated potential ganglion compression in patients with a non-stenotic foramen at C5-6 and C6-7; in patients with a stenotic foramen the injury risk greatly increases and spreads to include the C3-4 through C6-7 as well as C4-5 through C6-7 nerve roots.
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Affiliation(s)
- Yasuhiro Tominaga
- Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut 06520-8071, USA
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20
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Vassiliou T, Kaluza G, Putzke C, Wulf H, Schnabel M. Physical therapy and active exercises--an adequate treatment for prevention of late whiplash syndrome? Randomized controlled trial in 200 patients. Pain 2006; 124:69-76. [PMID: 16697113 DOI: 10.1016/j.pain.2006.03.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2005] [Revised: 01/27/2006] [Accepted: 03/27/2006] [Indexed: 11/17/2022]
Abstract
The aim of this study was to compare the effect of a physical therapy regimen including active exercises with the current standard treatment on reduction of pain 6 weeks and 6 months after whiplash injury caused by motor vehicle collision. Two hundred patients were enrolled in a prospective randomized controlled trial. In the standard group, treatment consisted of immobilization with a soft collar over 7 days. In the physical therapy group, patients were scheduled for 10 physical therapy appointments including active exercises within 14 days after enrollment. Pain intensity was rated by all patients daily during the first week, the sixth week, and 6 months after recruitment, using a numeric rating scale (0-10). Data analyses were performed by comparing the mean (over 1 week) pain scores between the two different treatment groups. Ninety-seven patients were randomly assigned to the standard treatment group and 103 to the physical therapy group. During the first week, there was no significant difference in mean pain intensity between the standard treatment group (4.76+/-2.15) and the physical therapy group (4.36+/-2.14). However, after 6 weeks, mean pain intensity was significantly (p=0.002) lower in the physical therapy group (1.49+/-2.26 versus 2.7+/-2.78). Similarly, after 6 months, significantly (p<0.001) less pain was reported in the physical therapy group (1.17+/-2.13) than the standard treatment group (2.33+/-2.56). We conclude that a physical therapy regimen which includes active exercises is superior in reducing pain 6 weeks and 6 months after whiplash injury compared to the current standard treatment with a soft collar.
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Affiliation(s)
- Timon Vassiliou
- Department of Anesthesiology and Critical Care, University Hospital Marburg, Baldingerstrasse 1, 35033 Marburg, Germany.
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21
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Abstract
STUDY DESIGN A biomechanical study of intervertebral foraminal narrowing during simulated automotive rear impacts. OBJECTIVES To quantify foraminal width, height, and area narrowing during simulated rear impact, and evaluate the potential for nerve root and ganglion impingement in individuals with and without foraminal spondylosis. SUMMARY OF BACKGROUND DATA Muscle weakness and paresthesias, documented in whiplash patients, have been associated with neural compression within the cervical intervertebral foramen. To our knowledge, no studies have comprehensively examined dynamic changes in foramen dimensions. METHODS There were 6 whole cervical spine specimens (average age 70.8 years) with muscle force replication and surrogate head that underwent simulated rear impact at 3.5, 5, 6.5, and 8 g, following noninjurious baseline 2 g acceleration. Peak dynamic narrowing of foraminal width, height, and area were determined during each impact and statistically compared to baseline narrowing. RESULTS Significant increases (P < 0.05) in average peak foraminal width narrowing above baseline were observed at C5-C6 beginning with 3.5 g impact. No significant increases in average peak foraminal height narrowing were observed, while average peak foraminal areas were significantly narrower than baseline at C4-C5 at 3.5, 5, and 6.5 g. CONCLUSIONS Extrapolation of the present results indicated that the highest potential for ganglia compression injury was at the lower cervical spine, C5-C6 and C6-C7. Acute ganglia compression may produce a sensitized neural response to repeat compression, leading to chronic radiculopathy following rear impact.
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Affiliation(s)
- Manohar M Panjabi
- Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
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22
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Lu Y, Chen C, Kallakuri S, Patwardhan A, Cavanaugh JM. Neural response of cervical facet joint capsule to stretch: a study of whiplash pain mechanism. STAPP CAR CRASH JOURNAL 2005; 49:49-65. [PMID: 17096268 DOI: 10.4271/2005-22-0003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Cervical facet joints are implicated as a major source of pain after whiplash injury. The purpose of this study was to investigate the proposed capsule strain injury mechanism of whiplash pain using neurophysiologic methods. Strain thresholds, threshold distribution, saturation strains and afterdischarge responses of capsule neural receptors were characterized in vivo. Goat C5-C6 facet joint capsules were used to identify and characterize capsule receptors in response to controlled uniaxial stretch by recording C6 dorsal rootlet nerve discharge. The joints were stretched at 0.5 mm/sec in a series of tests with 2 mm increments until the capsule ruptured. Ninety-two identified units were responsive to physiologic or noxious stretch while 28 were silent receptors. Among the 50 characterized responsive units, 42 showed low strain thresholds at 10.2+/-4.6% while 8 had high strain thresholds at 47.2+/-9.6%. Further, 35 of the 42 low-threshold units displayed discharge saturation at various strains (44.2+/-16.7%). A significant finding was that twelve low-threshold units exhibited afterdischarge for greater than 30 sec after stretch release at 36.6+/-12.5% strains, and displayed longer-lasting afterdischarge (greater than 4 min) at higher strains (39.0+/-14.4%) with significant difference (p = 0.019) in strains. Two high-threshold units had afterdischarges for greater than 30 sec or 4 min at 50.3+/-5.9% and 57.7+/-10.6% strains, respectively. In addition, the spatial distribution of the 42 low-threshold receptors demonstrated that the receptors on the joint gap were more strain-sensitive, with significantly lower strain thresholds compared to the rostral and caudal regions. No significant difference in strain threshold was observed in the medial-lateral direction. When compared to the reported strains that facet joint capsules experienced in whiplash (35-60%) and the reported capsule subfailure strains (35-67%), the low strain thresholds are substantially lower whereas the high thresholds and afterdischarge strains are within that range. Thus, low threshold units appear to signal proprioception within the physiologic range. High threshold units likely signal nociception (pain sensation) while afterdischarge may signal capsule strain injury and contribute to persistent pain.
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Affiliation(s)
- Ying Lu
- Bioengineering Center, Wayne State University, Detroit, MI, 48202, USA.
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23
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Krave U, Höjer S, Hansson HA. Transient, powerful pressures are generated in the brain by a rotational acceleration impulse to the head. Eur J Neurosci 2005; 21:2876-82. [PMID: 15926935 DOI: 10.1111/j.1460-9568.2005.04115.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A rotational acceleration impulse to a head, as occurs at traffic accidents, sport injuries, assaults and falls, induces a diffuse brain damage that eventually could result in persistent neuropsychiatric deficits and neurodegeneration. Emphasis has been concentrated on the relative motion of the brain inside the skull during head impact, whereas less attention has been paid to whether intracranial pressure changes are generated and, if so, the implications thereof. In the present experimental study we investigated in an animal model system, based on rabbits, if a sagittal, anterior-posterior rotational acceleration of a head generated intracranial pressure changes, recorded by fibre optic pressure sensors, inserted ipsilaterally in the parieto-temporal and the occipital lobes. Two levels of rotational acceleration were used in the experiments; one higher, corresponding to the threshold limit for moderate diffuse brain injury, and one lower, close to being noninjurious. Several pressure recordings were performed in each rabbit at the two acceleration levels. The pressure recordings invariably revealed the same general characteristics of rapid, positive and negative pressures within the brain, with variations in amplitude and duration, lasting for up to 10 ms. A major finding was the generation of powerful negative pressures, as low as 0.3 bars in absolute pressure. The most prominent difference in amplitudes of the negative peak pressures between the two applied acceleration levels was demonstrated at the parieto-temporal location. The presented pressure recordings are the first to disclose the generation of transient, powerful intracerebral pressures at rotational acceleration of the head, which must be considered in studies of brain injury generation and distribution as well as prevention.
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Affiliation(s)
- Ulrika Krave
- Vehicle Safety, Department of Applied Mechanics, Chalmers University of Technology, SE 412 96 Göteborg, Sweden
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Panjabi MM, Ito S, Ivancic PC, Rubin W. Evaluation of the intervertebral neck injury criterion using simulated rear impacts. J Biomech 2005; 38:1694-701. [PMID: 15958227 DOI: 10.1016/j.jbiomech.2004.07.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Accepted: 07/09/2004] [Indexed: 11/18/2022]
Abstract
The Intervertebral Neck Injury Criterion (IV-NIC) is based on the hypothesis that intervertebral motion beyond the physiological limit may injure spinal soft tissues during whiplash, while the Neck Injury Criterion (NIC) hypothesizes that sudden changes in spinal fluid pressure may cause neural injury. Goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to correlate IV-NIC with soft-tissue injury, determine the IV-NIC injury threshold, and compare IV-NIC and NIC. Using a bench-top apparatus, rear-impacts were simulated at 3.5, 5, 6.5, and 8 g horizontal accelerations of the T1 vertebra. Pre- and post-whiplash flexibility tests measured the soft tissue injury threshold, i.e. significant increases in the intervertebral neutral zone (NZ) or range of motion (ROM) above corresponding baseline values. Extension IV-NIC peaks correlated well with NZ and ROM increases at C0-C1 and at C3-C4 through C7-T1 (r=0.64 and 0.62 respectively, p<0.001). Average IV-NIC injury thresholds (95% confidence limits) varied among the intervertebral levels and ranged between 1.5 (1.1, 1.9) at C5-C6 and 3.4 (2.4, 4.4) at C7-T1. The NIC injury threshold was 8.7 (7.7, 9.7) m2/s2, substantially less than the proposed threshold of 15 m2/s2. Results support the use of IV-NIC for determining the cervical spine injury threshold and injury severity. Advantages of IV-NIC include the ability to predict the intervertebral level, mode, severity, and time of the cervical spine soft-tissue injury.
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Affiliation(s)
- Manohar M Panjabi
- Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, 333 Cedar St., P.O. Box 208071, New Haven, CT, 06520-8071, USA.
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25
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Sizer PS, Poorbaugh K, Phelps V. Whiplash Associated Disorders: Pathomechanics, Diagnosis, and Management. Pain Pract 2004; 4:249-66. [PMID: 17173607 DOI: 10.1111/j.1533-2500.2004.04310.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Whiplash has been defined as an injury mechanism, an injury, a medico-legal or social dilemma, and a complex chronic pain syndrome. Whiplash associated disorders are frequent in the cervical spine, especially as a result of a motor vehicle accident. The mechanisms responsible for whiplash-related tissue trauma are complex and a clinician's understanding of these complexities lends to a more complete appreciation for the anatomical structures and pathological processes that are involved, as well as a comprehensive diagnosis and appropriate management. While several classification scales have been developed for whiplash associated disorders, a thorough and tissue-specific examination is merited. Management should be directed toward pain reduction and normalization of mechanics. While conservative measures can address many of clinical sequelae of whiplash, both invasive pain management procedures and surgical interventions may be paramount to a patient's complete recovery.
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Affiliation(s)
- Phillip S Sizer
- Texas Tech University Health Science Center, School of Allied Health, Doctorate of Science Program in Physical Therapy, Lubbock, Texas 79430, USA.
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26
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Abstract
STUDY DESIGN A biofidelic whole cervical spine model with muscle force replication was used to evaluate spinal canal pinch diameter (CPD) narrowing during simulated whiplash. OBJECTIVES To quantify CPD narrowing during simulated whiplash and to determine if whiplash resulted in a narrower post-whiplash CPD. SUMMARY OF BACKGROUND DATA Spinal cord injuries are uncommon in whiplash patients, although such injuries have been reported in those with narrow canals. It has been hypothesized that increased cerebral spinal fluid pressure during whiplash could injure neural tissues. METHODS The biofidelic model and a bench-top whiplash apparatus were used to simulate whiplash at 3.5, 5, 6.5, and 8 g accelerations of the T1 vertebra. The CPD was measured in the intact specimen in the neutral posture (neutral posture CPD) and under a 1.5 Nm static extension load (pre-whiplash CPD), during simulated whiplash (dynamic whiplash CPD), and again under a 1.5 Nm extension load following each whiplash simulation (post-whiplash CPD). RESULTS The average dynamic whiplash CPDs were significantly narrower (P < 0.05) than the corresponding pre-whiplash CPDs at accelerations of 3.5 g and above. The narrowest CPD was observed at C5-C6 during the 6.5 g simulation and was 3.5 mm narrower than the neutral posture CPD. In general, the average post-whiplash CPDs were not significantly narrower than the corresponding pre-whiplash CPDs. CONCLUSIONS Spinal cord injury during whiplash is unlikely in patients with average normal canal diameters. Cord compression following whiplash due to physiologic extension loading is not likely. Previous clinical studies have found that whiplash patients with narrow canals may be at risk of injury, and our results do not disprove it.
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Affiliation(s)
- Shigeki Ito
- Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA
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27
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Panjabi MM, Ito S, Pearson AM, Ivancic PC. Injury mechanisms of the cervical intervertebral disc during simulated whiplash. Spine (Phila Pa 1976) 2004; 29:1217-25. [PMID: 15167661 DOI: 10.1097/00007632-200406010-00011] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A kinematic analysis of cervical intervertebral disc deformation during simulated whiplash using the whole cervical spine with muscle force replication model was performed. OBJECTIVES To quantify anulus fibrosus fiber strain, disc shear strain, and axial disc deformation in the cervical spine during simulated whiplash. SUMMARY OF BACKGROUND DATA Clinical studies have documented acute intervertebral disc injury and accelerated disc degeneration in whiplash patients, although there has been no biomechanical investigation of the disc injury mechanisms. METHODS A bench-top sled was used to simulate whiplash at 3.5, 5, 6.5, and 8 g using six specimens. The 30 degrees and 150 degrees fiber strains, disc shear strains, and axial disc deformations during whiplash were compared with the sagittal physiologic levels. RESULTS Increases over sagittal physiologic levels (P < 0.05) were first observed during the 3.5 g simulation. Peak fiber strain was greatest in the posterior 150 degrees fibers (running posterosuperiorly), reaching a maximum of 51.4% at C5-C6 during the 8 g simulation. Peak disc shear strain was also greatest at the posterior region of C5-C6, reaching a maximum of 1.0 radian due to posterior translation during the 8 g simulation. Axial deformation at the anterior disc region exceeded physiologic levels at 3.5 g and above, while axial deformation at the posterior region exceeded physiologic limits only at C5-C6 at 6.5 g and 8 g. CONCLUSIONS The cervical intervertebral discs may be at risk for injury during whiplash because of excessive 150 degrees fiber strain, disc shear strain, and anterior axial deformation.
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Affiliation(s)
- Manohar M Panjabi
- Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
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28
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Ito S, Ivancic PC, Panjabi MM, Cunningham BW. Soft tissue injury threshold during simulated whiplash: a biomechanical investigation. Spine (Phila Pa 1976) 2004; 29:979-87. [PMID: 15105668 DOI: 10.1097/00007632-200405010-00006] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A newly developed biofidelic whole cervical spine (WCS) model with muscle force replication (MFR) was subjected to whiplash simulations of varying intensity, and the resulting injuries were evaluated through changes in the intervertebral flexibility. OBJECTIVES To identify the soft tissue injury threshold based on the peak T1 horizontal acceleration and the association between acceleration magnitude and injury severity resulting from simulated whiplash using the WCS + MFR model. SUMMARY OF BACKGROUND DATA Whiplash has been simulated using mathematical models, whole cadavers, volunteers, and WCSs. The measurement of injury (difference between prewhiplash and postwhiplash flexibilities) is possible only using the WCS model. METHODS Six WCS + MFR specimens (C0-T1) were incrementally rear-impacted at nominal T1 horizontal maximum accelerations of 3.5, 5, 6.5, and 8 g, and the changes in the intervertebral flexibility parameters of neutral zone and range of motion were determined. The injury threshold acceleration was the lowest T1 horizontal peak acceleration that caused a significant increase in the intervertebral flexibility. RESULTS The first significant increase (P <0.01) of 39.8% occurred in the C5-C6 extension neutral zone following the 5 g acceleration. At higher accelerations, the injuries spread among the surrounding levels (C4-C5 to C7-T1). CONCLUSIONS A rear-end collision is most likely to injure the lower cervical spine by intervertebral hyperextension at a peak T1 horizontal acceleration of 5 g and above. These results may aid in the design of injury prevention systems and more precise diagnoses of whiplash injuries.
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Affiliation(s)
- Shigeki Ito
- Biomechanics Research Laboratory, Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA
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Guéz M, Hildingsson C, Rosengren L, Karlsson K, Toolanen G. Nervous Tissue Damage Markers in Cerebrospinal Fluid after Cervical Spine Injuries and Whiplash Trauma. J Neurotrauma 2003; 20:853-8. [PMID: 14577863 DOI: 10.1089/089771503322385782] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Clinical examination is the only tool available to assess the extent of the nerve tissue damage after a spinal cord injury, and it is well known that the reliability of classification based on clinical examination is not satisfactory, especially in cases with incomplete motor injuries. There is a need to evaluate new methods in order to improve the possibilities of classifying and prognosticating spinal cord injuries. Methods for assessing central nervous system (CNS) damage using markers in cerebrospinal fluid (CSF) have recently been developed. Previous studies have reported glial fibrillary acidic protein (GFAp) and neurofilament protein (NFL) levels in non-traumatic diseases in the central nervous system. The present study is the first report of GFAp and NFL levels in CSF after trauma to the cervical spine. Six cases with cord damage and pronounced neurological deficit showed significantly increased concentrations of both GFAp and NFL in the CSF. Patients with tetrapareses showed higher values than those with incomplete injuries. Three of the 17 whiplash cases had increased levels of NFL, but normal GFAp. Assessment of nervous tissue markers in CSF will probably improve possibilities to classify and prognosticate spinal cord injuries and also to evaluate pharmacological intervention. The increased levels of NFL in three whiplash cases indicate neural damage in a proportion of the cases with neurological deficit. Neurological examinations are presently the only tools for grading and prognostication of spinal cord injuries. Assessment of nervous tissue markers in CSF makes it possible to quantify the degree of nerve cell damage after different types of cervical spine injury ranging from spinal cord lesions to whiplash injuries.
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Affiliation(s)
- Michel Guéz
- Department of Ortopaedics, Umeå University Hospital, 90185 Umeå, Sweden.
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31
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Säljö A, Huang YL, Hansson HA. Impulse noise transiently increased the permeability of nerve and glial cell membranes, an effect accentuated by a recent brain injury. J Neurotrauma 2003; 20:787-94. [PMID: 12965057 DOI: 10.1089/089771503767870014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A single exposure to intense impulse noise may cause diffuse brain injury, revealed by increased expression of immediate early gene products, transiently altered distribution of neurofilaments, accumulation of beta-amyloid precursor protein, apoptosis, and gliosis. Neither hemorrage nor any gross structural damage are seen. The present study focused on whether impulse noise exposure increased the permeability of nerve and glial cell membranes to proteins. Also, we investigated whether a preceding, minor focal surgical brain lesion accentuated the leakage of cytosolic proteins. Anaesthetized rats were exposed to a single impulse noise at either 199 or 202 dB for 2 milliseconds. Transiently elevated levels of the cellular protein neuron specific enolase (NSE) and the glial cytoplasmic protein S-100 were recorded in the cerebrospinal fluid (CSF) during the first hours after the exposure to 202 dB. A surgical brain injury, induced the day before the exposure to the impulse noise, was associated with significantly increased concentrations of both markers in the CSF. It is concluded that intense impulse noise damages both nerve and glial cells, an effect aggravated by a preexisting surgical lesion. The impulse of the shock wave, i.e. the pressure integrated over time, is likely to be the injurious mechanism. The abnormal membrane permeability and the associated cytoskeletal changes may initiate events, which eventually result in a progressive diffuse brain injury.
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Affiliation(s)
- Annette Säljö
- Institute of Anatomy and Cell Biology, University of Göteborg, Göteborg, Sweden
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32
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Wenngren BI, Pettersson K, Lowenhielm G, Hildingsson C. Eye motility and auditory brainstem response dysfunction after whiplash injury. Acta Otolaryngol 2002; 122:276-83. [PMID: 12030574 DOI: 10.1080/000164802753648150] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The aim of this study was to identify the prevalence of brain/brainstem dysfunction after acute whiplash trauma (grades II and III according to the Quebec Task Force Classification on whiplash-associated disorders) and to investigate a possible correlation between the development of chronic symptoms and objective findings from auditory brainstem response (ABR) and eye motility tests. We used ABR and oculomotor tests and a thorough clinical, subjective and psychological evaluation in a sample of prospective whiplash trauma patients who were followed up for 2 years after the trauma. The initial test results did not reveal any prognostic clinical signs for the tested group as a whole, but we could discriminate some patients with clinical symptoms and signs paired with pathologic test results. Over time, some patients normalized clinically and their test results improved while others deteriorated clinically and their test results were worse at the 2-year investigation. Our findings of moderate derangements in the tests could be the effects of pain and/or changed cervical afferent activity at the brain/brainstem level, while eye motility dysfunction, in addition to pathological neuro-otological findings in a small proportion of the patients with severe symptoms, could be explained by lesions to the brain/brainstem.
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Affiliation(s)
- B I Wenngren
- Department of Otorhinolaryngology, University of Umeå, Sweden.
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33
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Croft AC, Herring P, Freeman MD, Haneline MT. The neck injury criterion: future considerations. ACCIDENT; ANALYSIS AND PREVENTION 2002; 34:247-255. [PMID: 11829295 DOI: 10.1016/s0001-4575(01)00020-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The cost of whiplash injuries--both in dollars spent for medical care and disability, and in terms of human suffering--are quite high in westernized nations. This is of particular interest both from a public health perspective and a general societal one because the disorder is theoretically preventable: in the very least it can be minimized. This can be achieved with crash prevention strategies and improvements in vehicle safety design--especially with more effective seat back and head restraint systems. Toward the goal of developing a gold standard for safety research in this area, a neck injury criterion (NIC) was proposed by Boström et al. in 1996 (Boström O., Svennson, M.Y., Aldman, B. et al., 1996. In: Proceedings of the International Conference on the Biomechanics of Impact, Dublin, Ireland). This criterion considers the relative horizontal acceleration and velocity between the bottom (T1) and top (C1) of the cervical spine and has face validity based on current literature. However, the NIC has still not been subjected to rigorous scientific investigation or validation in terms of its representativeness of human occupant injury. Such investigation should specifically consider, first, whether the NIC provides an adequate proxy for all potential neck injuries due to whiplash and, secondly, whether the proposed threshold value of 15 m2/s2 is an appropriate level for the stated goal. Based on a review of recent literature, recent human volunteer crash tests by Wheeler et al. and the those of the Spine Research Institute of San Diego, and based on mathematical MADYMO analysis of the first real world crash pulse data, it appears that the threshold for acute injury in the general population is likely to require a lowering of the originally proposed NIC value, and additional parameters, such as considering a forward rebound phase or neck extension criteria may be necessary. The conclusions of this paper should be considered preliminary because the numbers of crash test subjects and real world injury victims does not allow for rigorous statistical analysis. Certainly, ongoing work will be necessary to investigate this further and larger scale analysis of more onboard crash data will prove invaluable.
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Affiliation(s)
- Arthur C Croft
- Spine Research Institute of San Diego, Spring Valley, CA 91978, USA.
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34
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Brault JR, Siegmund GP, Wheeler JB. Cervical muscle response during whiplash: evidence of a lengthening muscle contraction. Clin Biomech (Bristol, Avon) 2000; 15:426-35. [PMID: 10771121 DOI: 10.1016/s0268-0033(99)00097-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To assess the potential for cervical muscle injury from a rear-end automobile collision. DESIGN Experimental design in which human subjects were exposed to low-speed rear-end collisions. The influence of independent variable (gender, speed change, muscle group, and motion phase) on dependent variables (kinematic response, muscle onset and muscle activation level) was examined using repeated-measures analysis of variance. BACKGROUND Injuries to various tissues of the cervical spine have been proposed, yet little attention has been focused on the cervical muscles as a site of injury. METHODS 42 subjects (21 males, 20-40 yr) were exposed to collisions of 4 and 8 km/h speed change while measuring kinematic response of the head and torso and electromyography of the sternocleidomastoid and cervical paraspinal muscles. RESULTS Muscle activation occurred earlier in females and in the 8 km/h speed change. Sternocleidomastoid onset preceded paraspinal onset. Muscle activation level varied significantly with speed change, motion phase and muscle group. Initial rearward retraction of the head relative to the torso resulted in lengthening of the activated sternocleidomastoid, consistent with a contraction-induced muscle injury. CONCLUSIONS The cervical muscles contract rapidly in response to impact and the potential exists for muscle injury due to lengthening contractions. RELEVANCE The clinician should recognize the role of cervical retraction in the mechanism of whiplash injury and avoid aggressive motion in that plane during diagnosis and treatment. An understanding of whiplash injury mechanisms should improve patient education and preventative measures.
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Affiliation(s)
- J R Brault
- Biomechanics Research and Consulting, Inc., El Segundo, CA 90245, USA.
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Adeboye KA, Emerton DG, Hughes T. Cervical sympathetic chain dysfunction after whiplash injury. J R Soc Med 2000; 93:378-9. [PMID: 10928030 PMCID: PMC1298067 DOI: 10.1177/014107680009300713] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- K A Adeboye
- Accident & Emergency Department, North Tees Health NHS Trust, Stockton-on-Tees, UK.
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Abstract
OBJECTIVES To review current knowledge and recent concepts of the causes of injuries after minor impact automobile collisions and to acquaint those who treat these types of injuries with possible injury thresholds and mechanisms that may contribute to symptoms. DATA SOURCES A review of literature involving mechanisms of injury, tissue tensile threshold, and neurologic considerations was undertaken. A hand-search of relevant engineering, medical/chiropractic, and computer Index Medicus sources in disciplines that cover the variety of symptoms was gathered. RESULTS Soft-tissue injuries are difficult to diagnose or quantify. There is not one specific injury mechanism or threshold of injury. With physical variations of tissue tensile strength, anatomic differences, and neurophysiologic considerations, such threshold designation is not possible. CONCLUSIONS To make a competent assessment of injury, it is important to evaluate each patient individually. The same collision may cause injury to some individuals and leave others unaffected. With the variability of human postures, tensile strength of the ligaments between individuals, body positions in the vehicle, collagen fibers in the same specimen segment, the amount of muscle activation and inhibition of muscles, the size of the spinal canals, and the excitability of the nervous system, one specific threshold is not possible. How individuals react to a stimulus varies widely, and it is evident peripheral stimulation has effects on the central nervous system. It is also clear that the somatosensory system of the neck, in addition to signaling nociception, may influence the control of neck, eyes, limbs, respiratory muscles, and some preganglionic sympathetic nerves.
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Svensson MY, Boström O, Davidsson J, Hansson HA, Håland Y, Lövsund P, Suneson A, Säljö A. Neck injuries in car collisions--a review covering a possible injury mechanism and the development of a new rear-impact dummy. ACCIDENT; ANALYSIS AND PREVENTION 2000; 32:167-175. [PMID: 10688473 DOI: 10.1016/s0001-4575(99)00080-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A review of a few Swedish research projects on soft tissue neck injuries in car collisions is presented together with some new results. Efforts to determine neck injury mechanisms was based on a hypothesis stating that injuries to the nerve root region in the cervical spine are a result of transient pressure gradients in the spinal canal during rapid neck bending. In experimental neck trauma research on animals, pressure gradients were observed and indications of nerve cell membrane dysfunction were found in the cervical spinal ganglia. The experiments covered neck extension, flexion and lateral bending. A theoretical model in which fluid flow was predicted to cause the transient pressure gradients was developed and a neck injury criterion based on Navier-Stokes Equations was applied on the flow model. The theory behind the Neck Injury Criterion indicates that the neck injury occurs early on in the rearward motion of the head relative to the torso in a rear-end collision. Thus the relative horizontal acceleration and velocity between the head and the torso should be restricted during the early head-neck motion to avoid neck injury. A Bio-fidelic Rear Impact Dummy (BioRID) was developed in several steps and validated against volunteer test results. The new dummy was partly based on the Hybrid III dummy. It had a new articulated spine with curvature and range of motion resembling that of a human being. A new crash dummy and a neck injury criterion will be very important components in a future rear-impact crash test procedure.
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Affiliation(s)
- M Y Svensson
- Crash Safety Division, Chalmers University of Technology, Göteborg, Sweden.
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Eichberger A, Darok M, Steffan H, Leinzinger PE, Boström O, Svensson MY. Pressure measurements in the spinal canal of post-mortem human subjects during rear-end impact and correlation of results to the neck injury criterion. ACCIDENT; ANALYSIS AND PREVENTION 2000; 32:251-260. [PMID: 10688481 DOI: 10.1016/s0001-4575(99)00097-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The aim of this study is to validate the pressure effect theory on human beings during a realistic rear-end impact and to correlate the neck injury criterion to pressure in the spinal canal. Sled experiments were performed using a test setup similar to real rear-end collisions. Test conditions were chosen based on accident statistics and recordings of real accidents. In particular, velocity change and acceleration level were reproduced similar to actual collisions. The head restraint as well as the seat back were adjusted to different positions. Two small pressure transducer were implemented to the spinal canal of postmortem human subjects and pressure measurement similar to the pig experiments (using exactly the same equipment) were performed. A total set of 21 experiments with four different subjects were performed. The subjects were additionally instrumented with triaxial accelerometers that allowed for calculation of the NIC criterion. Results showed that NIC and pressure amplitudes of the CSF correlate well and therefore NIC seems to be able to predict these amplitudes also for human beings. Conclusions whether these pressure effects induce soft tissue neck injuries or not could not be drawn and should be investigated in further research.
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Affiliation(s)
- A Eichberger
- Institute for Mechanics, University of Technology, Graz, Austria.
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Pettersson K, Toolanen G. High-dose methylprednisolone prevents extensive sick leave after whiplash injury. A prospective, randomized, double-blind study. Spine (Phila Pa 1976) 1998; 23:984-9. [PMID: 9589535 DOI: 10.1097/00007632-199805010-00004] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
STUDY DESIGN A prospective, randomized, double-blind study comparing high-dose methylprednisolone with placebo. OBJECTIVES To evaluate the efficacy of high-dose methylprednisolone when administered within 8 hours after whiplash injury. SUMMARY OF BACKGROUND DATA Whiplash injury often results in chronic symptoms. The management of whiplash injuries is controversial, and pharmacologic therapy has received little evaluation. In recent reports, dysfunction of the central nervous system has been indicated in several cases. Methylprednisolone administered within 8 hours after the injury to patients with acute spinal cord injury has been demonstrated to improve the outcome. This procedure was also adopted in a randomized study of cases of whiplash injury in car accidents. METHODS Forty patients, 22 men and 18 women with a mean age of 35 years (range, 19-65), were included in the study, 20 in each of two groups. They were treated for whiplash injury, which they had sustained in car accidents. The patients were enrolled if their diagnoses were complete and treatment had begun within 8 hours after injury. Disabling symptoms severe enough to prevent the patient from returning to work, number of sick days before and after injury, and sick-leave profile after injury were used as parameters for the evaluation of the effects of the treatment. Baseline demographic data were controlled for when statistical analysis had been performed. RESULTS At the follow-up examination 6 months after initial treatment, there was a significant difference in disabling symptoms between the actively treated patients and the placebo group (P = 0.047), total number of sick days (P = 0.01), and sick-leave profile (P = 0.003). CONCLUSIONS The results of this study indicate that acute treatment with high-dose methylprednisolone may be beneficial in preventing extensive sick leave after whiplash injury. However, the number of patients studied was small, and therefore further prospective, controlled studies are needed.
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Affiliation(s)
- K Pettersson
- Department of Orthopaedics, Umeå University, Sweden
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Waxman SG, Rizzo MA. The whiplash (hyperextension-flexion) syndrome: a disorder of dorsal root ganglion neurons? J Neurotrauma 1996; 13:735-9. [PMID: 9002059 DOI: 10.1089/neu.1996.13.735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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