Chronic Pain Adaptations and Interventions - PowerPoint Presentation

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Chronic Pain Adaptations and Interventions

By Kyle Wolfe

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Learning Objectives

Participants will be able to describe the anatomy and mechanisms that contribute to the pain systems in the body.

Participants will be able to describe changes that can be found in chronic pain patients based on current research.

Participants will be able to identify potential novel interventions to treat patients in chronic pain based on new research on pain systems.

Participants will be able to apply combinations of intervention to create a treatment plan for a patient with chronic pain.

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Chronic Pain 1

Pain that is:

“persisting more than a specified amount of time, typically 3-6 months”

“Long-lasting, persistent, and of sufficient duration and intensity to adversely affect a patient’s well-being, function, and quality of life”

“persists past the healing phase following an injury with impairment greater than anticipated based on the injury or occurs in the absence of injury or tissue damage”

Also called “Persistent Pain”

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Pain Anatomy Review 1

Receptors:

Processed peripherally by nociceptors found in the skin and subcutaneous tissue

Free nerve endings are the main type of receptor

Found superficially in skin and subcutaneous tissue, deep in joint receptors, and within muscle and tendon fascia

GTO and other receptors can also transmit some pain info, especially paresthesia

Processed along different nerves for different stimuli

A-delta, C, etc.

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Pain Processing

1

Combination of input from nociceptors, mechanoreceptors, chemoreceptors, and other smaller contributors

Processed via the anterolateral spinothalamic pathway from peripheral -> central

Processed initially in the brain in the somatosensory (s1 and s2) areas prior to cortical areas

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Pain Processing – Gate Theory

1

pain fibers synapse with inter/secondary neurons to transmit signals

Interneurons also get input from other nerves, mostly a-alpha and a-beta

Stimulation of a-

a

and a-

b

neurons can “close the gate” which inhibits the pain signal at the interneuron

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Pain Processing – Descending Inhibition

1

Appear to work via opioid system and using Ach, serotonin, noradrenaline, and glycine to modulate pain

Many brain areas involved (hypothalamus, amygdala, rostral anterior cingulate cortex, periaqueductal gray, rostral ventromedial medulla) as well as dorsal horn of spine

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Descending Inhibition 1

When is a situation in which you might suffer an injury but not feel the pain from it until later?

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Pain Processing – Changes in Chronic Pain

2,3,8

In chronic widespread pain (fibromyalgia) – reduced serotonin, NE, dopamine found in descending pathways

Prolonged sensation of pain following repetitive stimuli

Increased temporal summation

More widespread brain activity occurs in central pain areas in those with chronic pain compared to controls

Chronic pain patients have reduced exercise-induced hypoalgesia, and even increases in pain with exercises

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Pain Processing – Changes in Chronic Pain

2,3

Nociceptive Flexion Reflex:

Controls: reflex decreases when the contralateral limb is submerged in ice water

In chronic pain patients:

Less stimulation needed to excite NFR

NFR does not decrease in one limb when other is submerged

Less descending modulation of the reflexes

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Peripheral Sensitization

1, 9

Nociceptive input or sensation is increased based on:

Decreased threshold

Increased responsiveness

And/or increased receptive field

Inflammation in neural or peripheral tissues contributes

Substance P, cytokines, etc.

Lowered pain pressure threshold at site of injury compared to contralateral side

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Central sensitization

1,9

Wind-up

: repeated, low-frequency stimulation results in an increase action potential in dorsal horn

Hyperalgesia occurs based on amplified synapses in dorsal horn

Hypothalamic-Pituitary-Adrenal

Axis:

activated during physical or emotional stress, starts a cascade that results in sympathetic activation of pain systems

Changes in glia,

astrocytes, synapses, inflammation, immune

responses

, etc.

Can occur in visceral conditions as well, such as IBSCan create new synapses

from

efferent neurons on peripheral nociceptors

Can lead to

widespread

pain, fatigue,

sleep

disturbances

, cognitive

difficulties

,

altered

CNS

processing

, and

even

changes

with

secondary

hyperalgesia

or

referred

pain

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Mechanism Model 9

Biological Mechanisms:

Nociceptive (Peripheral)

Typically localized to area of injury during normal tissue healing time frame

Nociplastic

(Central)

Modulated signals in CNS by cortex and pathways

Neuropathic

Usually has some sort of positive neural signs

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Mechanism Model

9, 10, 11

4. Psychosocial

Negative emotional factors

Pain catastrophizing and Kinesiophobia are predictive of pain and disability following induction of injury

5. Movement Systems

Ex: antalgic gait, overuse syndromes, withdrawal reflex

Pain causes changes in muscle tone, fear-avoidance, disuse and changes surrounding muscle groups

Shoulder pain reduces muscle output and strength in deltoids, and this is reduced when pain is reduced

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Brain Plasticity

1,4

Can occur at any age on a large scale, but young brains continuously change while older brains change based on behavioral functions and context

Changes are based on modulatory neurotransmitters (Ach/DA/NA)

“What Fires Together, Wires Together”

Weakens or eliminates synapses that do not contribute to these behaviors

Plastic changes are typically reversible

Intensive training can reorganize brain pathways:

Violin players and braille readers have changing cortical areas and pathways based on the amount of experience they have in playing

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Adaptions to Pain – Smudging

5

Chronic back pain patients have lower proprioceptive acuity, cortical changes related to sensation of their back, and less movement capabilities of pelvis and trunk

Moseley Study:

5/6 back pain patients stated they couldn’t find their back and had trouble drawing it

6/6 back pain patients did not draw all the vertebrae, leaving out ones in the specific areas of pain

Vertebrae were shifted towards the side with pain in all patients

Increase in TPD was proportional with disrupted body image levels

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Adaptation to pain – Tactile Acuity

4,6

Patients with chronic pain have a larger two-point discrimination touch distance at the site of pain that compared to unaffected limbs or controls

Positive correlation between pain intensity and TPDT

Treatments for tactile acuity have been shown to have benefits in patients with chronic pain

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Potential Cortical Changes

1,4,5,7

Sensitization leads to larger pain focused areas in S1, gray matter atrophy, and brain morphology changes

In CRPS patients: perceived affected limb to be larger, but it had a smaller cortical area

Back pain patients: affected LB area seems smaller to patients, but is larger in cortical area

Recent CRPS study did not find cortical changes based on pain severity or location

Restoring cortical representation compared to unaffected sides reduced pain levels

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Interventions

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Pain Neuroscience Education

3,6,12,13

Educational intervention with goal of teaching pain physiology and the nervous system processing of pain to increase understand and reduce patient experiences

Aim: pain = body feels a threat more than safety; pain =/= injury!

Use of images, stories, details and explanation of sensitization, synaptic changes, and regulation of the nervous system to show complexities of how the pain experience changes

Provides reassurance to patients about their diagnosis, prognosis, and pain experiences

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Pain Neuroscience Education

3,6,12,13

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Patient Example

Steve is 55 years old. Steve comes to you with a history of low back pain on and off for about 4 years, but worsened in the last 9 months

Steve tells you he got an MRI and his back has “a really bad slipped disc” and “it’s out of place”

The MRI report from 4 months ago shows a moderate bulge of the disc at L4/L5

What can you tell

steve

before you do any other treatments that could help?

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Pain Neuroscience Education

3,6,12-13, 20-21

Ex: “No correlation between MRI stenosis findings and severity of pain”

Ex: 64% of asymptomatic people had at least some level of bulge in lumbar spine, with 27% having a full protrusion

Can also utilize:

Metaphors/stories

Booklets

Drawings

Workbooks or assignments

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Pain Neuroscience Education

3,6,12,13

Some studies have shown:

Use pre-operatively improved post-operative outcomes for lumbar discectomy

Improvements in pain and QOL with PNE > traditional pain education for LBP

Decreased fear of injury, catastrophizing and function; increased ROM, movement capabilities, and positive feelings towards control of pain at up to 1 year follow-up

Immediate improvements following PNE in attitudes towards pain and patient diagnosis, pain threshold during activity, therapeutic exercise outcomes, and more

Is not as effective as a stand-alone treatment for all outcomes

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Pain Neuroscience Education

3,6,12,13

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Graded Motor Imagery 14,15

Intervention with goal of engaging cortical motor networks without producing pain response to rewire circuits

Typically prescribed in 3-stages with each being 2-weeks long:

Left-Right Judgements

Motor/Mental Imagery

Mirror Therapy

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Graded Motor Imagery 14,15

Ordered GMI reduces pain in chronic pain patients compared to unordered GMI

Ordered GMI reduced pain and improved function in patients with CRPS

Mirror therapy has the most support as a stand-alone intervention for pain

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Tactile Discrimination Training

4

Used to try to reverse cortical changes and restore sensory-motor interactions without painful response

Self-Paced Training daily using:

Bi-Manual Training

Speed Training

Memory Game

Significant improvements in pain level, disability levels, and two-point discrimination training

Greater improvements when combined with mirror training

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Exercise Based Interventions

1,11,16-19

General Concepts:

Graded exposure reinforces hurt

=/=

harm and decreases fear-avoidance behaviors

Helps habituation to dulled pain response with movement

Exercise has shown improvements for all 5 pain mechanisms

Regular exercise reduces central excitability and increases both pain thresholds and pain inhibition

Combined with pain education shows greater benefits than no education or anatomy education

Benefits seen with aerobic, strength, Tai Chi, Yoga, and Aquatic for pain

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Exercise Based Interventions

1,11,16-19

Need some strengthening component

In Fibromyalgia patients: Strengthening, strengthening + Aerobic improved pain, just aerobic exercise did not

Chronic neck/shoulder pain: strength training significantly improved both pain and motor function compared to aerobic exercise or education

Neck Pain: adhering to strength program for 1 year gives significant benefits in pain and function that are still seen after 3 years, even if program is stopped

Isometric Contractions

In patellar pain patients, 5 reps x 45 seconds had greater immediate pain relief compared to isotonic 4 x 8 at same intensity

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Resources to utilize

Explain Pain

by David Butler and Lorimer Moseley

Reconciling Biomechanics with Pain Science – Greg Lehman

Pain Neuroscience Education: Teaching People About Pain

&

Why Do I Hurt?

–

Adriaan

Louw

Tame the Beast

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Questions

?

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References

O’Sullivan SB, Thomas J. Schmitz T, Fulk G. Physical Rehabilitation. 6th ed. Philadelphia: F.a. Davis; 2013:1505.

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Louw A, Puentedura EJ, Diener I, Peoples RR. Preoperative therapeutic neuroscience education for lumbar radiculopathy: a single-case fMRI report. Physiother Theory

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Schmid A-C, Schwarz A,

Gustin

SM, Greenspan JD, Hummel FC,

Birbaumer

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Scand

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Moseley GL. I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain. Pain. 2008;140(1):239-243. doi:10.1016/j.pain.2008.08.001

Catley

MJ, O’Connell NE, Berryman C,

Ayhan

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Mancini F, Wang AP,

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I, Arik MI,

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Gokpinar

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Traeger AC, O’Hagan ET, Cashin A, McAuley JH. Reassurance for patients with non-specific conditions - a user’s guide.

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Bowering KJ, O’Connell NE, Tabor A, et al. The effects of graded motor imagery and its components on chronic pain: a systematic review and meta-analysis. J Pain. 2013;14(1):3-13. doi:10.1016/j.jpain.2012.09.007

Smart KM, Wand BM, O’Connell NE. Physiotherapy for pain and disability in adults with complex regional pain syndrome (CRPS) types I and II. Cochrane Database Syst Rev. 2016;2:CD010853. doi:10.1002/14651858.CD010853.pub2

Rio E, van Ark M, Docking S, et al. Isometric Contractions Are More Analgesic Than Isotonic Contractions for Patellar Tendon Pain: An In-Season Randomized Clinical Trial. Clin J Sport Med. 2017;27(3):253-259. doi:10.1097/JSM.0000000000000364

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. 2018;98(5):302-314. doi:10.1093/

ptj

/pzy030

Wang C, Schmid CH,

Rones

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