Objective-The objective of this preliminary study was to determine if high-velocity, lowamplitude spinal manipulation (HVLA-SM) thrust duration alters mechanical trunk activation thresholds of nociceptive-specific (NS) lateral thalamic neurons.Methods-Extracellular recordings were obtained from 18 NS neurons located in 2 lateral thalamic nuclei (ventrolateral [n = 12] and posterior [n = 6]) in normal anesthetized Wistar rats. Response thresholds to electronic von Frey anesthesiometer (rigid tip) mechanical trunk stimuli applied in 3 lumbar directions (dorsal-ventral, 45° caudal, and 45° cranial) were determined before and immediately after the delivery of 3 HVLA-SM thrust durations (time control 0, 100, and 400 milliseconds). Mean changes in mechanical trunk activation thresholds were compared using a mixed model analysis of variance.Results-High-velocity, low-amplitude spinal manipulation duration did not significantly alter NS lateral thalamic neurons' mechanical trunk responses to any of the 3 directions tested with the anesthesiometer.Copyright © 2014 by National University of Health Sciences.Submit requests for reprints to: William R Reed, DC, PhD, 741 Brady St, Davenport, IA 52803. (william.reed@palmer.edu). Potential Conflicts of Interest No conflicts of interest were reported for this study Contributorship Information Concept development (provided idea for the research): W.R.R. Design (planned the methods to generate the results): W.R.R., J.G.P., R.S.S. Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): W.R.R. Data collection/processing (responsible for experiments, patient management, organization, or reporting data): W.R.R., R.S.S. Analysis/interpretation (responsible for statistical analysis, evaluation, and presentation of the results): W.R.R., J.G.P., S.M.O., R.S.S. Literature search (performed the literature search): W.R.R., S.M.O., R.S.S. Writing (responsible for writing a substantive part of the manuscript): W.R.R., S.M.O. Critical review (revised manuscript for intellectual content, this does not relate to spelling and grammar checking): W.R.R., J.G.P., S.M.O., R.S.S.The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
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Author ManuscriptConclusions-This study is the first to examine the effect of HVLA-SM thrust duration on NS lateral thalamic mechanical response thresholds. High-velocity, low-amplitude spinal manipulation thrust duration did not affect mechanical trunk thresholds.
Key Indexing TermsManipulation; Spinal; Thalamus; Nociceptive Neuron; Lumbar Vertebrae; ChiropracticSpinal manipulation has been shown to be effective in treating neck and low back pain. [1][2][3] Not only are the neurophysiological mechanisms by which this occurs unknown, but a lack of knowledge also exists regarding the effects of clinician-controlled mechanical application parameters o...