Discussion

Korr, Irvin M.

doi:10.1007/978-1-4684-8902-6_16

Cited by 8 publications

(10 citation statements)

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“…Thus, the rapid thrust of an HVLA-SM appears to engage an inherent signaling property of the muscle spindle apparatus (for more extensive discussion see section 4.2 of Pickar and Bolton, 2012). While the barrage of sensory input to the central nervous system during the manipulative thrust is postulated as one neural mechanism contributing to HVLA-SM’s therapeutic effects of HVLA-SM (Korr, 1975; Korr, 1978; Haldeman, 1983; Gillette, 1987; Greenman, 1989; Pickar, 2002; Leach, 2004; Henderson, 2005; Bialosky et al, 2009; Pickar and Bolton, 2012), its contribution to these effects has not yet been established.…”

Section: Discussionmentioning

confidence: 99%

“…Although the mechanistic pathways underlying the effects of HVLA-SM are not yet known, muscle spindles were chosen because changes in neural input arising from co-activated paraspinal sensory receptors (Korr, 1978; Haldeman, 1983; Gillette, 1987; Greenman, 1989; Pickar, 2002; Leach, 2004; Henderson, 2005; Bialosky et al, 2009; Pickar and Bolton, 2012), including muscle spindles (Korr, 1975), have long been thought to contribute to HVLA-SM’s therapeutic effects. Studying sensory input from paraspinal tissues in humans has not been possible due to the invasive nature of these procedures.…”

Section: Introductionmentioning

confidence: 99%

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Neural responses to the mechanical characteristics of high velocity, low amplitude spinal manipulation: Effect of specific contact site

et al. 2015

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Background Systematic investigations are needed identifying how variability in the biomechanical characteristics of spinal manipulation affects physiological responses. Such knowledge may inform future clinical practice and research study design. Objective To determine how contact site for high velocity, low amplitude spinal manipulation (HVLA-SM) affects sensory input to the central nervous system. Design HVLA-SM was applied to 4 specific anatomic locations using a no-HVLA-SM control at each location randomized in an 8×8 Latin square design in an animal model. Methods Neural activity from muscle spindles in the multifidus and longissimus muscles were recorded from L6 dorsal rootlets in 16 anesthetized cats. A posterior to anterior HVLA-SM was applied through the intact skin overlying the L6 spinous process, lamina, inferior articular process and L7 spinous process. HVLA-SMs were preceded and followed by simulated spinal movement applied to the L6 vertebra. Change in mean instantaneous discharge frequency (ΔMIF) was determined during the thrust and the simulated spinal movement. Results All contact sites increased L6 muscle spindle discharge during the thrust. Contact at all L6 sites significantly increased spindle discharge more than at the L7 site when recording at L6. There were no differences between L6 contact sites. For simulated movement, the L6 contact sites but not the L7 contact site significantly decreased L6 spindle responses to a change in vertebral position but not to movement to that position. Conclusions This animal study showed that contact site for an HVLA-SM can have a significant effect on the magnitude of sensory input arising from muscle spindles in the back.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Neural responses to the mechanical characteristics of high velocity, low amplitude spinal manipulation: Effect of specific contact site

et al. 2015

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“…35–38 Spinal manipulation is thought to elicit a barrage of sensory activity from a diverse set of spinal joint and paraspinal tissue mechanoreceptors which in turn influence spinal reflexes and/or subcortical processing to alter motoneuron output resulting in positive clinical outcomes. 36–46 We previously showed that only when the thrust of an HVLA-SM is delivered at a clinically relevant duration (≤150ms) does a very high frequency discharge occur from paraspinal muscles.…”

Section: Introductionmentioning

confidence: 99%

Paraspinal Muscle Spindle Response to Intervertebral Fixation and Segmental Thrust Level During Spinal Manipulation in an Animal Model

Reed

Pickar

2015

Spine

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Study Design In vivo cat model study. Objective To determine whether intervertebral facet joint fixation and segmental thrust level alter paraspinal muscle spindle activity during simulated spinal manipulation. Summary of Background Data Intervertebral motion is commonly assessed by manual therapy practitioners during clinical evaluation and treatment. Mechanoreceptor activity elicited during spinal manipulation has been theorized as a potential mechanism of its efficacy. The degree to which intervertebral fixation and segmental thrust level alter paraspinal muscle spindle activity during high velocity low amplitude spinal manipulation (HVLA-SM) is unclear. Methods Intervertebral fixation was created by inserting facet screws through the left L5–6, L6–7 and left L4–5, L5–6, L6–7, facet joints of a cat spine. Changes in the mean instantaneous frequency of L6 muscle spindle discharge were determined during five HVLA-SM thrust durations ((0-control, 75, 100, 150, 250ms) delivered at the L4 or L6 spinous process in each of 3 conditions within the same preparation: laminectomy-only (surgical control; n=23), L5–6 and L6–7 fixations (n=20), and L4–5, L5–6, and L6–7 fixations (n=7). Comparisons were made between thrust levels, thrust durations and spinal joint conditions using a linear mixed model. Results Insertion of facet screws compared to laminectomy-only significantly increased (P<.001) lumbar spinal stiffness during L6 HVLA-SM. Compared to laminectomy-only, both the 2 facet screw (100ms; P<.05) and 3 screw conditions [75 and 100ms (P<.001), 150 ms (P<.005), and 250 ms (P<.05)] significantly decreased L6 spindle response during the L6 HVLA-SM. HVLA-SM delivered 2 segments rostral to the level of muscle spindle input significantly decreases spindle response compared to HVLA-SM delivered at-level, however non-target HVLA-SM still elicits 60–80% of at-level muscle spindle response. Conclusions Intervertebral fixation decreases paraspinal muscle spindle response during L6 HVLA-SM in a cat model. While HVLA-SM target accuracy maximizes spindle response, non-target HVLA-SM still elicits substantial levels of muscle spindle activity.

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“…A commonality shared by a majority of spinal manipulative studies that investigated H-reflex and stretch reflex responses is the concept that manual therapies mechanistically act by reflexively reducing central α-motoneuron activity via modulating the sensitivity of muscle spindle afferents to muscle stretch. 37,41–48 Using a computer-controlled feedback motor, we have previously investigated the relationship between various biomechanical parameters of spinal manipulation (thrust duration, thrust magnitude, thrust rate, thrust contact site etc.) and paraspinal muscle spindle responsiveness in both laminectomy-only and acute facet joint fixation animal models.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Paraspinal Muscle Spindle Response to Mechanically Assisted Spinal Manipulation: A Preliminary Report

Reed

Pickar

Sozio

et al. 2017

Journal of Manipulative and Physiological Therapeutics

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Objectives The purpose of this preliminary study is to determine muscle spindle response characteristics related to the use of two solenoid powered clinical mechanically-assisted manipulation (MAM) devices. Methods L6 muscle spindle afferents with receptive fields in paraspinal muscles were isolated in 6 cats. Neural recordings were made during L7 MAM thrusts using the Activator V and/or Pulstar devices at their 3 lowest force settings. MAM response measures included: a) the time required post-thrust until the 1st action potential, b) differences in mean frequency (MF) and mean instantaneous frequency (MIF) 2s before and after MAM, and c) the time required for muscle spindle discharge (MF & MIF) to return to 95% of baseline following MAM. Results Depending on device setting, between 44–80% (Pulstar) and 11–63% (Activator V) of spindle afferents required >6s to return to within 95% of baseline MF values; whereas 66–89% (Pulstar) and 75–100% (Activator V) of spindle responses returned to within 95% of baseline MIF in <6s following MAM. Nonparametric comparisons between the 22 and 44N settings of the Pulstar yielded significant differences for the time required to return to baseline MF and MIF. Conclusion Short duration (<10ms) MAM thrusts decrease muscle spindle discharge with a majority of afferents requiring prolonged periods of time (>6s) to return to baseline MF activity. Physiological consequences and/or clinical relevance of described MAM mechanoreceptor responses will require additional investigation.

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Discussion

Cited by 8 publications

References 0 publications

Neural responses to the mechanical characteristics of high velocity, low amplitude spinal manipulation: Effect of specific contact site

Neural responses to the mechanical characteristics of high velocity, low amplitude spinal manipulation: Effect of specific contact site

Paraspinal Muscle Spindle Response to Intervertebral Fixation and Segmental Thrust Level During Spinal Manipulation in an Animal Model

Characteristics of Paraspinal Muscle Spindle Response to Mechanically Assisted Spinal Manipulation: A Preliminary Report

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