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Low Speed Rear-End Collisions Mechanism of Injury www.InjuryResources.com © Copyright 2002, BodyMind Publications.

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Presentation on theme: "Low Speed Rear-End Collisions Mechanism of Injury www.InjuryResources.com © Copyright 2002, BodyMind Publications."— Presentation transcript:

1 Low Speed Rear-End Collisions Mechanism of Injury © Copyright 2002, BodyMind Publications.

2 Viano and Gargan documented the head restraint position of 1,915 vehicles at an intersection. They found that only 10% of the occupants had the head restraint in the proper position to avoid hyperextension. Only ¼ of the adjustable head restraints were in the “up” position. Viano DC, Gargan MF. Headrest position during normal driving: implication to neck injury risk in rear crashes. Accident Analysis and Prevention 1996;28(6): Improper Head Restraint Positioning Proper Head Restraint Positioning

3 1. Normal Position2. Spine Straightens 3. Head Extension4. Rebound The Phases of a Rear-End Collision

4 Car seat begins to move forward Occupant remains stationary, due to inertia No occupant forces 0 milliseconds

5 Car seat pushes into occupants torso Torso is accelerated forward with the seat Head is still stationary, due to inertia 100 milliseconds

6 Torso fully accelerated by the car seat Lower neck is pulled forward by the rapidly moving torso Causing the head to rotate backward over the head restraint 150 milliseconds

7 Head is still moving backwards Car seat begins to spring forward Torso is again accelerated forward 175 milliseconds

8 Head and torso are accelerated forward ahead of the car seat, resulting in flexion of the spine 300 milliseconds

9 Normal Cervical Spine

10 Normal, smooth curvature of the spine Each intervertebral joint contributes evenly to the motion Normal Cervical Spine Extension

11 Normal Flexion and Extension Normal spinal motion results from small motions in each individual vertebral joint. The normal motion of each joint is limited to just a few degrees of movement. Click on image to start or pause video

12 0 milliseconds At the moment of impact, the car seat just begins to move and the occupant has not yet been accelerated forward. Motion During a Collision

13 As the car seatback pushes the torso forward, the spine moves forward, resulting in a straightening of the thoracic and cervical spine. Head remains stationary Seatback pushes torso forward 50 milliseconds Spine straightens

14 This difference in motion between the neck and torso results in an S-shaped curve, where nearly all of the bending in the cervical spine takes place in the lower cervical spine. This rapid bending in just a few joints can result in ligament damage in the lower spine. At this point in the collision, the car seat is rapidly pushing the occupant's torso forward, while the head remains stationary due to inertia. Head remains stationary Seatback pushes torso forward 75 milliseconds Motion During a Collision Spine forms an abnormal S-shape formation

15 75 milliseconds50 milliseconds Spine StraightensS-Shaped Curve Injury Causing Motion

16 At about 150 milliseconds, the torso has pulled so far forward on the lower neck that the head is forced backwards over the head restraint. Depending on the severity of the collision, the ligaments in the front portion of the spine can be injured during this phase of the collision. Head rotates back Seatback pushes torso forward 150 milliseconds Motion During a Collision

17 Finally, the head and torso are thrown forward by the force of the car seat. Head thrown forward Force from car seat 200 milliseconds Motion During a Collision

18 Ligaments of the Cervical Spine Facet capsular ligaments

19 Vertebral Body Facet Joints Intervertebral Disc Spinous Process Facets Normal Gliding Motion The Cervical Facet Joints

20 The Facet Joint Facet joint X-ray of facet joint. The arrows show the normal gliding motion of these joints.

21 Normal Facet Motion The cervical vertebrae are designed for smooth, even motion. The facet joints stabilize the spine and allow this forward and backward movement. Click on image to start or pause video

22 Animation of Abnormal Spinal Motion During a low speed, rear-end collision, the movement of the head and neck is focused on just a few spinal segments. This results in the s- shaped curve motion that can cause injury. Click on image to start or pause video

23 Normal vs. Abnormal Motion Normal Flexion/Extension: Smooth, even motion of all spinal segments Abnormal S-Shaped Curve: Dramatic movement in just a few spinal segments Click on image to start or pause video

24 Pinching of facet Torso movement forward Torso moving forward Tearing of ligaments and disc Facet Joint Reflectors Stretch of facet capsule Abnormal Facet Motion

25 Vertebral Motion During Impact Instead of a smooth motion, the cervical spine experiences simultaneous compression and shear. This can cause tearing in the front portion of the spine and pinching in the facet joints. Click on image to start or pause video

26 The rapid motion of the neck during a crash can result in a number of injuries - many of which are impossible to see on x-rays or MRI. Here are some of the injuries that have been shown after whiplash crashes. 1.Rim Lesions 2.Endplate avulsions 3.Tears of the anterior longitudinal ligament 4.Uncinate process 5.Articular subchondral fractures 6.Articular pillar 7.Articular process 8.Ligament Tear Areas of Injury

27 The pain from inflamed facet joints is transmitted by the medial branch of the dorsal ramus. Stimulation of the facet nerves often results in referred pain. Facet Joints Medial Branch Dorsal Ramus Spinous Process Spinal Cord Nerves of the Facet Joint

28 "... the prevalence of cervical zygapophysial joint pain was 60%." The most common facets to be injured were at C2/C3 and C5/C6. Wallis BJ, Lord SM, Bogduk N. Resolution of psychological distress of whiplash patients following treatment by radiofrequency neurotomy: a randomised, double- blind, placebo-controlled trial. Pain 1997;73: C2/3, C3 C3/4, C4/5, C4 C6/7, C6, C7 C2/3, C3/4, C3 C4/5, C5/6, C4, C5 C4/5, C5/6, C4 C7/T1, C7 Referred Pain Patterns

29 Bibliography Barnsley L, Lord SM, Wallis BJ, Bogduk N. The prevalence of chronic cervical zygapophysial joint pain after whiplash. Spine 1995;20: Bogduk N. Post whiplash syndrome. Australian Family Physician 1994;23: Brault JR, Wheeler JB, Siegmund GP, Brault EJ. Clinical response of human subjects to rear-end automobile collisions. Archives of Physical Medicine and Rehabilitation 1998;79: Eichberger A, Darok M, Steffan H, Leinzinger PE, et al. Pressure measurements in the spinal canal of post-mortem human subjects during rear-end impact and correlation of results to the Neck Injury Criterion (NIC). Traffic Safety and Auto Engineering Stream of the World Congress on Whiplash-Associated Disorders, 1999: Farmer CM, Wells JK, Werner JV. Relationship of head restraint positioning to driver neck injury in rear-end crashes. Traffic Safety and Auto Engineering Stream of the World Congress on Whiplash-Associated Disorders, 1999: Continued…

30 Fukui S, Ohseto K, Shiotani M et al. Referred pain distribution of the cervical zygapophysial joints and cervical dorsal rami. Pain 1996;68: Grauer JN, Panjabi MM, Cholewicki J, Nibu K, Dvorak J. Whiplash produces an s-shaped curvature of the neck with hyperextension at lower levels. Spine 1997;22: Insurance Institute for Highway Safety, Press Release, April 7, Insurance Institute for Highway Safety, Status Report, (4). Insurance Institute for Highway Safety, Status Report, (5). Kaneoka K, Ono K, Inami S, Hayashi K. Motion analysis of cervical vertebrae during simulated whiplash loading. Traffic Safety and Auto Engineering Stream of the World Congress on Whiplash-Associated Disorders 1999: Kornhauser M. Delta-V thresholds for cervical spine injury. 1996, SAE Kumar S, Narayan Y, Amell T. Role of awareness in head-neck acceleration in low velocity rearend impacts. Compendium of papers presented at the Traffic Safety and Auto Engineering Stream, World Congress on Whiplash- Associated Disorders 1999; Lord SM, Barnsley L, Wallis BJ, Bogduk N. Chronic cervical zygapophysial joint pain after whiplash: a placebo-controlled prevalence study. Spine 1996;21(15): Continued…

31 Lord SM, Barnsley L, Wallis BJ, et al. Percutaneous radio-frequency neurotomy for chronic cervical zygapophysial joint pain. New England Journal of Medicine 1996;335(23): Lord SM, Barnsley L, Wallis BJ, et al. Percutaneous radio-frequency neurotomy for chronic cervical zygapophysial joint pain. New England Journal of Medicine 1996;335(23): Matsushita T, Sato TB, Hirabayashi K, et al. X-ray study of the human neck motion due to head inertia loading. 38th Stapp Car Crash Conference 1994; SAE Matsushita T, Sato TB, Hirabayashi K, et al. X-ray study of the human neck motion due to head inertia loading. 38th Stapp Car Crash Conference 1994; SAE Ono K, Kaneoka K, Wittek A, Kajzer J. Cervical injury mechanism based on the analysis of human cervical vertebral motion and head-neck-torso kinematics during low speed rear impacts. Society of Automotive Engineers, 41 st STAPP Car Crash Conference Proceedings 1997; SAE Ono K, Kaneoka K, Wittek A, Kajzer J. Cervical injury mechanism based on the analysis of human cervical vertebral motion and head-neck-torso kinematics during low speed rear impacts. Society of Automotive Engineers, 41 st STAPP Car Crash Conference Proceedings 1997; SAE Ortengren T, Hansson HA, Lovsund P, et al. Membrane leakage in spinal ganglion nerve cells induced by experimental whiplash extension motion: a study in pigs. Journal of Neurotrauma 1996;13(3): Ortengren T, Hansson HA, Lovsund P, et al. Membrane leakage in spinal ganglion nerve cells induced by experimental whiplash extension motion: a study in pigs. Journal of Neurotrauma 1996;13(3): Robbins MC. Lack of relationship between vehicle damage and occupant injury. SAE Robbins MC. Lack of relationship between vehicle damage and occupant injury. SAE Siegmund GP, Brault JR, Wheeler JB. The relationship between clinical and kinematic responses from human subject testing in rear-end automobile collisions. Traffic Safety and Auto Engineering Stream of the World Congress on Whiplash-Associated Disorders, 1999: Siegmund GP, Brault JR, Wheeler JB. The relationship between clinical and kinematic responses from human subject testing in rear-end automobile collisions. Traffic Safety and Auto Engineering Stream of the World Congress on Whiplash-Associated Disorders, 1999: Siegmund GP, King DJ, Lawrence, JM, et al. Head/neck kinematic response of human subjects in low-speed rear-end collisions. Society of Automotive Engineers, 41 st STAPP Car Crash Conference Proceedings 1997; SAE Siegmund GP, King DJ, Lawrence, JM, et al. Head/neck kinematic response of human subjects in low-speed rear-end collisions. Society of Automotive Engineers, 41 st STAPP Car Crash Conference Proceedings 1997; SAE Continued…

32 Szabo TJ, Welcher JB. Human subject kinematics and electromyographic activity during low speed rear impacts. 40th Stapp Car Crash Conference, SAE Szabo TJ, Welcher JB. Human subject kinematics and electromyographic activity during low speed rear impacts. 40th Stapp Car Crash Conference, SAE van den Kroonenberg A, Philippens M, Cappon H, et al. Human head-neck response during low-speed rear end impacts. 42 nd Stapp Car Crash Conference Proceedings (P-227), SAE van den Kroonenberg A, Philippens M, Cappon H, et al. Human head-neck response during low-speed rear end impacts. 42 nd Stapp Car Crash Conference Proceedings (P-227), SAE Viano DC, Gargan MF. Headrest position during normal driving: implication to neck injury risk in rear crashes. Accident Analysis and Prevention 1996;28(6): Viano DC, Gargan MF. Headrest position during normal driving: implication to neck injury risk in rear crashes. Accident Analysis and Prevention 1996;28(6): Wallis BJ, Bogduk N. Faking a profile: can naïve subjects simulate whiplash responses? Pain 1996;66: Wallis BJ, Bogduk N. Faking a profile: can naïve subjects simulate whiplash responses? Pain 1996;66: Wallis BJ, Lord SM, Barnsley L, Bogduk N. Pain and psychologic symptoms of Australian patients with whiplash. Spine 1996;21(7): Wallis BJ, Lord SM, Barnsley L, Bogduk N. Pain and psychologic symptoms of Australian patients with whiplash. Spine 1996;21(7): Wallis BJ, Lord SM, Barnsley L, Bogduk N.The psychological profiles of patients with whiplash-associated headache. Cephalgia 1998;18: Wallis BJ, Lord SM, Barnsley L, Bogduk N.The psychological profiles of patients with whiplash-associated headache. Cephalgia 1998;18: Wallis BJ, Lord SM, Bogduk N. Resolution of psychological distress of whiplash patients following treatment by radiofrequency neurotomy: a randomised, double-blind, placebo-controlled trial. Pain 1997;73: Wallis BJ, Lord SM, Bogduk N. Resolution of psychological distress of whiplash patients following treatment by radiofrequency neurotomy: a randomised, double-blind, placebo-controlled trial. Pain 1997;73: Yoganandan N, Pintar FA, Cusick JF. Biomechanical analyses of whiplash injuries using experimental model. Traffic Safety and Auto Engineering Stream of the World Congress on Whiplash-Associated Disorders 1999: Yoganandan N, Pintar FA, Cusick JF. Biomechanical analyses of whiplash injuries using experimental model. Traffic Safety and Auto Engineering Stream of the World Congress on Whiplash-Associated Disorders 1999:

33 Live Occupant Footage Credit The crash test footage is copyrighted by Biomechanics Research and Testing. Permission to use this footage was generously provided by: Biomechanics Research and Testing, LLC 1827 Ximeno Ave Ste 2 Long Beach, CA Phone: (562) Fax: (562) The video they produce contains crash test footage of five collisions between 1-6 miles per hour, and includes all of the data gathered during the crash tests.


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