To review the evidence related to the morphological changes (atrophy and fatty degeneration) of neck muscles in whiplash-associated disorders (WAD) and to highlight emerging evidence for the pathophysiological mechanisms behind muscle degeneration and their potential role in the transition from acute to chronic pain after whiplash injury from a motor vehicle crash (MVC).
Magnetic resonance imaging (MRI) can be regarded as the gold standard for muscle imaging. There is emerging evidence to highlight in vivo features of neck muscle degeneration in patients with chronic WAD and the temporal development of such acute changes after MVC. However, the precise underlying mechanisms for such changes and their influence on functional recovery after whiplash remain largely unknown.
Literature review of available evidence from both the authors’ previous studies and other similar bodies of work.
Studies have quantified degenerative changes in the neck muscles of patients with acute and chronic whiplash with structural MRI applications.
Current evidence from structural MRI based studies demonstrates the widespread presence of fatty infiltrates in neck muscles of patients with chronic whiplash. Such findings have not shown to feature in patients with chronic insidious onset neck pain, suggesting traumatic factors play a role in their development. Recent studies have revealed that muscle fatty infiltrates manifest soon after whiplash but only in those with higher pain and disability and symptoms of post-traumatic stress disorder. The possibility that such muscle changes are associated with a more severe injury including poor functional recovery remains the focus of current research efforts.
Studies have quantified fatty degeneration in the neck muscles of patients with chronic whiplash. Such changes develop soon after injury but only in those with higher pain levels and post-traumatic stress. It is possible that such objective muscle changes are associated with a more severe injury and poor functional recovery.
From the Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL
Address correspondence and reprint requests to James M. Elliott, Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611; E-mail: firstname.lastname@example.org
Acknowledgment date: June 9, 2011. First revision date: July 21, 2011. Second revision date: September 13, 2011. Acceptance date: September 19, 2011.
The manuscript submitted does not contain information about medical device(s)/drug(s).
The Australian Physiotherapy Research Foundation and The Centre for National Research on Disability and Rehabilitation Medicine (CONROD), University of Queensland provided funding for the work. JE received a post-doctoral fellowship from The Centre for Research Excellence in Spinal Pain, Injury and Health (CCRE-Spine), University of Queensland (2008-2010). No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.