Defining the Effect of Cervical Manipulation on Vertebral Artery Integrity: Establishment of an Animal Model
Received 19 May 2003
Background
Cervical spine manipulation is most often performed to affect relief of musculoskeletal complaints of the head and neck. Performed typically without complication, this modality is thought to be a potential cause of cerebrovascular injury, although a cause-effect relation has yet to be established. To explore this relation, an experimental platform is needed that is accessible and biologically responsive.
Objective
To establish an animal model capable of accommodating (1) direct study of its vertebral arteries and (2) creation of controlled interventions simulating arterial injury.
Study Design
Descriptive.
Methods
Under fluoroscopic guidance, an ultrasonic catheter was inserted into the left vertebral artery of 3 anesthetized dogs. The ultrasonic probe was then drawn proximally through the artery at a specific rate, and cross-sectional images of the vessel were collected. These images were then reconstructed to provide a variety of 2- and 3-dimensional representations of the vessel. This procedure was repeated after the overinflation and/or displacement of an angiographic balloon within the vertebral artery itself.
Results
The resulting ultrasonic images were able to delineate the structural layers that constitute the vertebral artery. Analysis of 2- and 3-dimensional reconstructions before and after angiographic intervention revealed the creation of discrete vascular injuries (aneurysm or dissection).
Conclusions
For the first time, an animal model has been established that permits direct interrogation of the internal structures of the vertebral artery. This model can also be manipulated to create “preexisting” vascular injuries that are thought to be possible prerequisites for cerebrovascular injury associated with manipulation. As a result, an experimental platform has been established that is capable of providing investigators of all backgrounds with the ability to quantify biologic and mechanical outcomes of cervical manipulation.
aFaculty of Rehabilitation Medicine, University of Alberta, Alberta, Canada
bGraduate Student, University of Calgary, Alberta, Canada
cFaculty of Medicine, University of Calgary, Alberta, Canada
Submit requests for reprints to: Greg Kawchuk, DC, PhD, Faculty of Rehabilitation Medicine, University of Alberta, 2-28 Corbett Hall, Edmonton, Alberta, Canada T6G 2G4
Sources of support: Financial support for materials used in this work was provided in part by the Canadian Chiropractic Protective Association. The authors receive salary support through the Canadian Institutes of Health Research and the Canadian Chiropractic Association (Dr Kawchuk), the Alberta Provincial CIHR Training Program in Bone and Joint Health (Dr Wynd), and by the Alberta Heritage Foundation for Medical Research (Dr Anderson).
ABSTRACT