Muscle Pathologies After Cervical Spine Distortion-Like Exposure—A Porcine Model

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.

Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.

Keywords:

• whiplash
• cervical spine distortion
• porcine
• neck muscles
• rear-end impact

Acknowledgments

This study is part of the ADSEAT project (Adaptive Seat to Reduce Neck Injuries for Female and Male Occupants), Project No. 233904, Work package 2 “Biological Tests.” The ADSEAT project is funded by the European Commission for Research as part of the Seventh Framework Programme. We are grateful to Prof. Dr. Med. Benedikt Schoser, neurologist at the Friedrich-Bauer-Institute in Munich, for his great support in the examination of the histological muscle samples. Further, we thank Prof. Dr. Andreas Nehrlich and Dr. Helmut Rohrbach from the pathology department at the Hospital Munich-Bogenhausen for the allocation of the microscope and staining support.