Abstract
A study was conducted to find out whether in a rear-impact motor vehicle accident, velocity changes in the impact vehicle of between 10 and 15 km/h can cause so-called “whiplash injuries”. An assessment of the actual injury mechanism of such whiplash injuries and comparison of vehicle rear-end collisions with amusement park bumper car collisions was also carried out. The study was based on experimental biochemical, kinematic, and clinical analysis with volunteers. In Europe between DM 10 and 20 billion each year is paid out by insurance companies alone for whiplash injuries, although various studies show that the biodynamic stresses arising in the case of slight to moderate vehicle damage may not be high enough to cause such injuries. Most of these experimental studies with cadavers, dummies, and some with volunteers were performed with velocity changes below 10 km/h. About 65% of the insurance claims, however, take place in cases with velocity changes of up to 15 km/h. Fourteen male volunteers (aged 28–47 years; average 33.2 years) and five female volunteers (aged 26–37 years; average 32.8 years) participated in 17 vehicle rear-end collisions and 3 bumper car collisions. All cars were fitted with normal European bumper systems. Before, 1 day after and 4–5 weeks after each vehicle crash test and in two of the three bumper car crash tests a clinical examination, a computerized motion analysis, and an MRI examination with Gd-DTPA of the cervical spine of the test persons were performed. During each crash test, in which the test persons were completely screened-off visually and acoustically, the muscle tension of various neck muscles was recorded by surface eletromyography (EMG). The kinematic responses of the test persons and the forces occurring were measured by accelerometers. The kinematic analyses were performed with movement markers and a screening frequency of 700 Hz. To record the acceleration effects of the target vehicle and the bullet vehicle, vehicle accident data recorders were installed in both. The contact phase of the vehicle structures and the kinematics of the test persons were also recorded using high-speed cameras. The results showed that the range of velocity change (vehicle collisions) was 8.7–14.2 km/h (average 11.4 km/h) and the range of mean acceleration of the target vehicle was 2.1–3.6 g (average 2.7 g). The range of velocity change (bumper car collisions) was 8.3–10.6 km/h (average 9.9 km/h) and the range of mean acceleration of the target bumper car was 1.8–2.6 g (average 2.2 g). No injury signs were found at the physical examinations, computerized motion analyses, or at the MRI examinations. Only one of the male volunteers suffered a reduction of rotation of the cervical spine to the left of 10° for 10 weeks. The kinematic analysis very clearly showed that the whiplash mechanism consists of translation/extension (high energy) of the cervical spine with consecutive flexion (low energy) of the cervical spine: hyperextension of the cervical spine during the vehicle crashes was not observed. All the tests showed that the EMG signal of the neck muscles starts before the head movement takes place. The stresses recorded in the vehicle collisions were in the same range as those recorded in the bumper car crashes. From the extent of the damage to the vehicles after a collision it is possible to determine the level of the velocity change. The study concluded that, the “limit of harmlessness” for stresses arising from rear-end impacts with regard to the velocity changes lies between 10 and 15 km/h. For everyday practice, photographs of the damage to cars involved in a rear-end impact are essential to determine this velocity change. The stress occurring in vehicle rear-end collisions can be compared to the stress in bumper car collisions.
Key words: Whiplash, Clinical cervical examination, MRI, Spine injuries, Rear-end collision
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References
- 1.Deutscher C (1994) Bewegungsablauf von Fahrzeuginsassen beim Heckaufprall. Eurotax (International), Freienbach
- 2.Eichberger A (1995) Beschleunigungsverletzungen der HWS bei PKW/PKW-Heckkollisionen im realen Unfallgeschehen. Thesis, Graz University
- 3.Analyse von PKW-Unfällen. Grundlagen für künftige Forschungsarbeiten. Munich: Büro für Kfz.-Technik; 1994. [Google Scholar]
- 4.Holthöfer F (1982) Verletzungsschwelle im HWS-Bereich bei Pkw-Kollisionen. Thesis, Munich University
- 5.Kalthoff W. Experimentelle Untersuchung der Möglichkeiten und Grenzen der Fahrzeugbeschädigungen nach PKW-Auffahrkollisionen. Osnabrück: University of Applied Science; 1997. [Google Scholar]
- 6.Kamieth H. Das Schleudertrauma der Halswirbelsäule. In: Schulitz KP, editor. Die Wirbelsäule in Forschung und Praxis. Stuttgart: Hippokrates; 1990. p. 7. [Google Scholar]
- 7.McConnell WE, Howard RP, Guzmann HM, Bomar JB, Benedict JV, Smith HL, Hatsell CP. Analysis of human test subject kinematic responses to low velocity rear end impacts. Warrendale: Society of Automotive Engineers; 1993. [Google Scholar]
- 8.Meyer S, Hugemann W, Weber M. Zur Belastung der Halswirbelsäule durch Auffahrkollisionen. 1. Verkehrsunfall Fahrzeugtechnik. 1994;32:15–21. [Google Scholar]
- 9.Meyer S, Hugemann W, Weber M. Zur Belastung der Halswirbelsäule durch Auffahrkollisionen. 2. Verkehrsunfall Fahrzeugtechnik. 1994;32:187–199. [Google Scholar]
- 10.Penning L. Acceleration injury of the cervical spine by hypertranslation of the head. 1. Effect of normal translation of the head on cervical spine motion: a radiological study. Eur Spine J. 1992;1:7–12. doi: 10.1007/BF00302135. [DOI] [PubMed] [Google Scholar]
- 11.Scott MW, McConnell WE, Guzmann HM, Howard RP, Bomar JB, Smith HL, Benedict JV, Raddin JH, Hatsell CP. Comparison of human and ATD head kinematics during low speed rear end impacts. Warrendale: Society of Automotive Engineers; 1993. [Google Scholar]
- 12.Severy DM, Mathewson JH, Bechtol CO. Controlled automobile year-end collisions — an investigation of related engineering and medical phenomena. Can Serv Medi J. 1995;11:757–759. [PubMed] [Google Scholar]
- 13.Siegmund GP, Williamson PB. Speed change (ΔV) of amusement park bumper cars. Proceedings of the Canadian Multidisciplinary Road Safety Conference. 1993;8:299–308. [Google Scholar]
- 14.Steffan H, Geigl B. Zur Problematik von HWS-Verletzungen. Verkehrsunfall Fahrzeugtechn. 1996;34:35–39. [Google Scholar]
- 15.Steil R, Ehlers A. Die posttraumatische Belastungsstörung: eine Übersicht. Verhaltensmodif Verhaltensmed. 1996;17:169–212. [Google Scholar]
- 16.Stovner LJ. The nosologic status of the whiplash syndrome: a critical review based on a methodological approach. Spine. 1996;21:2735–2746. doi: 10.1097/00007632-199612010-00006. [DOI] [PubMed] [Google Scholar]
- 17.Szabo TJ, Welcher JB, Anderson RD, Rice MM, Ward JA, Paulo LR, Carpenter NJ. Human occupant kinematic response to low speed rear end impacts. Warrendale: Society of Automotive Engineers; 1994. [Google Scholar]
- 18.Szabo TJ, Welcher JB. Human subject kinematics and electromyographic activity during low speed rear impacts. Warrendale: Society of Automotive Engineers; 1996. [Google Scholar]
- 19.Goethem JMW, Biltjes IGGM, Hauwe L, Parizel PM, Schepper AMA. Whiplash injuries: is there a role for imaging? Eur J Radiol. 1995;22:8–14. doi: 10.1016/0720-048x(95)00696-n. [DOI] [PubMed] [Google Scholar]
- 20.West DH, Gough JP, Harper GTK. Low speed rear end collision testing using human subjects. Accid Reconstr J. 1993;5:22–26. [Google Scholar]