Charles Henderson, D.C., Ph.D. &
Gregory Cramer, D.C., Ph.D.
Palmer Center for Chiropractic Research / National College of
This proposal presents a comprehensive investigation of a small
animal model of spinal subluxation consisting of percutaneously
attached pins into the spinous process of two adjacent vertebrae.
These pins will then be experimentally manipulated, allowing the
full external, nontraumatic and reversible control of two key
features of the subluxation hypothesis: fixation and malposition.
This experimental system, the Rat Transcutaneous Spinous Fixation
Model [RTSFM] will be replicated by investigative teams at both
Palmer and National Colleges of Chiropractic to assure the
practicality of the model in terms of reproducibility, economy
and ease of construction.
Both the fixation and malposition elements of the RTSFM will be
evaluated by visual inspection [radiographically and at surgery
and autopsy] and by instrument-assisted biomechanical analysis
both in vivo and in vitro. Preliminary data to assess the
putative anatomical, biochemical, and electrophysiological
consequences of the subluxation will also be obtained. Examples
of the types of data to be extracted are histological changes of
the zygapophyseal [Z] joints, changs in receptor populations on
afferent neurons associated with the immobilzed Z joints, nerve
conduction velocity changes in dorsal roots near sites of
fixation or malposition, and alterations in neuromodulators to
The clinical relevance of the RTSFM model is demonstrated by its
ability to provide data relating to the following questions:
[i] Is there an optimum time window for applying spinal
[ii] What are the effects of changing biomechanical features
[simulating different chiropractic techniques];
[iii] What is the effect of repeated manipulation under
different states of the subject; and
[iv] can chiropractic subluxations alter visceral function?
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