Faculty Collaboration Database

Reflex muscle contraction in the unaware occupant in whiplash injury. Spine (Phila Pa 1976) 2005 Dec 15;30(24):2794-8; discussion 2799

Date

12/24/2005

Pubmed ID

16371906

DOI

10.1097/01.brs.0000192178.46869.42

Scopus ID

2-s2.0-29444434351 (requires institutional sign-in at Scopus site)   22 Citations

Abstract

STUDY DESIGN: Computer modeling and parametric analysis were used to determine the effect of reflex contraction of the neck muscles in the unaware occupant in whiplash.

OBJECTIVE: To delineate effects of reflex contraction on spinal segmental kinematics during the retraction phase.

SUMMARY OF BACKGROUND DATA: The ability of reflex neck muscle contraction to mitigate whiplash injury in the unaware occupant remains unclear. Analyzing relative timing between electromyographic and head-neck kinematics, previous investigators theorized that muscle contraction alters spinal kinematics, decreasing injury likelihood. Other investigators suggested that injury occurs during the initial (retraction) phase of head-neck kinematics, before significant muscle force generation.

METHODS: Computer modeling was used to determine reflex contraction effects on segmental angulations, implementing parametric analysis techniques to vary reflex delay and impact severity.

RESULTS: Shorter reflex delays had a greater effect on segmental angulations later in the event and at lower impact severities. However, the magnitude of this effect, particularly at higher impact severities and during maximum cervical S-curvature (factors implicated in the whiplash injury mechanism) was minimal, altering segmental angulations by a maximum of 19%.

CONCLUSIONS: Because reflex contraction did not substantially alter spinal kinematics, muscle contraction likely does not initiate in sufficient time to mitigate whiplash injuries that may occur during the retraction phase.

Author List

Stemper BD, Yoganandan N, Rao RD, Pintar FA

Authors

Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of Wisconsin
Brian Stemper PhD Professor in the Biomedical Engineering department at Medical College of Wisconsin
Narayan Yoganandan PhD Professor in the Neurosurgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Cervical Vertebrae
Computer Simulation
Electromyography
Models, Biological
Muscle Contraction
Neck Muscles
Reflex
Whiplash Injuries