Cervical human spine loads during traumatomechanical investigations

Kallieris, Dimitrios; Rizzetti, Andreas; Mattern, Rainer; Thunnissen, Jan; Philippens, Mat

The last decades improvements in automotive safety resulted into a significant decrease of fatal injuries. However, due to the use of belts and airbags it can be observed that cervical spine injuries, non-severe and severe, have become more important. It seems that inertial loading of the neck by the head is an important loading mechanism causing these injuries.

Until now local deformations and load paths in the cervical spine can not be determined accurately from cadaver experiments due to the lack of adequate measuring techniques. At this moment the loads at the occipital condyles can be estimated by analyzing high speed film and the linear and angular accelerations of the head. These loads show a correlation with (local) cervical spine injuries in car crashes.

The head-neck response, the neck loads and the sustained injuries obtained from human cadaver experiments in the frontal, lateral and rear-end collisions were investigated to increase the knowledge of the traumatomechanics of the cervical spine. The severity of these experiments, e.g. sled deceleration, varies from 11 to 15 g for frontal, and 7 g for rear-end collisions; for lateral impacts, the shoulder was accelerated with 100 to 130 g through the intruded side wall of the car.

It was observed, that rotational accelerations of 1000 rad/sec* do not lead to recognizable injuries during post mortem loadings, while rotational accelerations of 2000 - 3000 rad/sec2 or bending moments of 80 - 100 Nm can lead to injuries of ligaments, intervertebral discs and compression fractures of vertebral bodies. Shear forces in frontal collisions of 1000 - 1500 N at the level of the occipital condyles cause strength of the joints in this region. The resultant acceleration at the head centre of gravity varies from 20 to 45 g.

Year

Entry

1994

Geigl BC, Steffan H, Leinzinger P, Roll P, Mühlbauer M, Bauer G. The movement of head and cervical spine during rearend impact. In: Proceedings of the 1994 International IRCOBI Conference on the Biomechanics of Impact. September 21-23, 1994; Lyon, France.127-137.

1995

Geigl BC, Steffan H, Dippel C, Muser MH, Walz F, Svensson MY. Comparison of head-neck kinematics during rear end impact between standard Hybrid III, RID neck, volunteers and PMTO's. In: Proceedings of the 1995 International IRCOBI Conference on the Biomechanics of Impact. September 13-15, 1995; Brunnen, Switzerland.261-270.

1995

Walz FH, Muser MH. Biomechanical aspects of cervical spine injuries. In: Proceedings of the SAE International Congress & Exposition. February 27–March 2, 1995; Detroit, MI. Warrendale, PA: Society of Automotive Engineers. SAE 950658.

1975

Ewing CL, Thomas DJ, Lustick L, Becker E, Willems G, Muzzy WH. The effect of the initial position of the head and neck on the dynamic response of the human head and neck to -Gx impact acceleration. In: Proceedings of the 19th Stapp Car Crash Conference. November 17-19, 1975; San Diego, CA. Warrendale, PA: Society of Automotive Engineers:487-512. SAE 751157.

1993

McConnell WE, Howard RP, Guzman HM, Bomar JB, Raddin JH, Benedict JV, Smith HL, Hatsell CP. Analysis of human test subject kinematic responses to low velocity rear end impacts. In: Proceedings of the SAE International Congress & Exposition. March 1-5, 1993; Detroit, MI. Warrendale, PA: Society of Automotive Engineers:21-30. SAE 930889.