Presentation on theme: "Central Sensitization: Clinical Implications for Chronic Head and Neck Pain Arthur S. Roberts DDS, MD, MSc Indiana Craniofacial Center, PC Indiana University."— Presentation transcript:
Central Sensitization: Clinical Implications for Chronic Head and Neck Pain Arthur S. Roberts DDS, MD, MSc Indiana Craniofacial Center, PC Indiana University School of Dentistry Oral Medicine University of Edinburgh College of Medicine and Veterinary Medicine Pain Management
DISCLOSURES Innovative Health Solutions American Academy of Pain Management
WHY IS THIS IMPORTANT?
Prototype y/o female Extensive PMH Multiple prior providers Polypharmacy Often hypervigilant Either non-communicative or circumstantial May be none of the above!!!
Chronic Pain Is Not Acute Pain Pathologic not protective Multidimensional (Biopsychosocial) Entangled via neuromatrix Pan-Systemic
Chronic pain implies an altered neuromatrix “ The neuromatrix, which is genetically determined and modified by sensory experience, is the primary mechanism that generates the neural pattern that produces pain. Its output pattern is determined by multiple influences, of which the somatic sensory input is only a part, that converge on the neuromatrix.” Melzack 2001 * Emphasis added
Neuromatrix Is A Process
Central Sensitization “Sensory-afferent signals overwhelm the body's ability to filter them” [1,2]12 – neuro-immune dysfunction, – neuro-endodrine dysfunction – NMDA (N-methyl-D-aspartate) dysregulation – Sympatho-afferent coupling – Altered serotonin and norepinephrine production and utilization Melzach, Woolf 2001
Hypoactivity of the hypothalamic-pituitary- adrenal axis autonomic nervous system alterations increased sympathetic tone low vagal tone Immune abnormalities Fatigue Malaise [5,12,14,20,21,23-25,33-38]
Indicators for central sensitization. depression anxiety hyperalgesia allodynia stress related pain exacerbation fatigue poor sleep
Therapeutic Problems Polypharmacy different prescribing specialists iatrogenic contribution – failing to differentiate chronic from acute pain Symptomatic - Acute symptoms of CSS disorders need to be addressed Syndromic - Essential to treat the pathways in chronic pain disease [2,5,7,8,13-15,17,19,20,32]
Two approaches to CSS therapy Symptomatic approach: Address the effects of CS after it has occurred Syndromic approach: Interrupt the CS Optimal outcomes often depend on doing both. – Pharmacological – Non-pharmacological [1,4,6,8,13,14, 40-44]
. Pharmacological Approaches Treating the effects – Acetaminophen – Serotonin (SSRI) and norepinephrine (SNRI) reuptake inhibitors and tricyclic antidepressants (TCA) – Opioids and Tramadol Drugs that may treat the central sensitization itself: – N-methyl-D-aspartate (NMDA) receptor blockers Namenda, Ketamine, Memantine – Calcium channel alpha(2) ligands Gabapentin, Lyrica
Non-pharmacological Approaches (NPT) Each element of neuromatrix is potential therapeutic target Two broad operative groups: – Reducing CS itself – Responding to the effects of CS
Repetitive Transcranial Magnetic Stimulation (rTMS) Safe and non-invasive Stimulation of the motor cortex and prefrontal cortex Limited application – Short duration of effects – Significant equipment costs – Greater efficacy in centrally, rather than peripherally, originated pain – Reverses intra-cortical motor dysfunction – Alters sensory-discriminative function – Restores of descending inhibition – Improves cognitive function [56,57]5657 – Some investigators argue that the analgesic effects are independent of descending inhibitory control and are influenced by other elements of the neuromatrix 58
Manual Therapy Improves function Improves descending inhibition Widespread analgesia. Short duration Limited assistance in desensitizing the neuromatrix Addresses functional rehabilitation [4,13,60-64]
Virtual Reality Limited evidence Distraction in the hyper-vigilant patient Potential benefit in patients with movement associated nociceptive etiology Not in widespread use [13,65]1365
Improving Stress Tolerance and Neuro feedback Training Stress – Etiologic and exacerbating factor for CS – Endogenous (chronic pain) – Exogenous (psychosocial changes) – Irritable, hyper-excitable chronic pain patient – Related to sympatho-afferent coupling in the hypothalamic-pituitary- adrenal axis of the neuromatrix. – neuro-immune changes from upregulated pronociceptive immune mediators in primary afferent nociceptors Reduction of stress levels improves: Pain threshold Maladaptive behavior Autonomic balance [12,14,17,35,36,66-68]
Transcutaneous Electrical Nerve Stimulation Activates poly-segmental inhibitory feedback Significant effect with focal, segmental chronic pain Results in widespread pain are equivocal [13,40, 69-73]
Percutaneous Electroneural Stimulation (PENS) Percutaneous stimulation of peripheral branches of multiple cranial and cervical nerves Trigeminal, Vagus, Occipital – Discreet – Stimulates afferents improved autonomic regulation Improves centrally mediated pain Improves sensory - discriminatory functions serotonin/norepinephrine production and utilization endorphin production analgesia and mood improvement appears to follow a ‘learning curve’59 cost-effective, non-invasive, low co-morbidity option [1,2,5, 6,8-10,12-15,20-23,25-28,42-44,53, 55]
Once initiated central sensitization can engender additional presentations Increased frequency and intensity of pain Increased endogenous stress levels Increased sympatho-afferent coupling Autonomic dysfunction – anxiety – poor sleep – difficulty coping – lowered pain thresholds – increased risk of developing additional presentations of CS Persistent microglial inflammation [2,74]274
Removal Of The Initiating Stimulus Will Not Insure Favorable Outcomes Continuing stimulus for the development and/or maintenance of CS – Extended disease course – Additional CS presentations (syndromes) – Devolves to dealing with the effects of the CS rather than control or eradication of the CS [2,3,74]2374
Stress Induced CS No biological axis may exist in the early stages – Maladaptive behavior Engender biological issues Contribute to maintenance and exacerbation of CS – PTSD – Depression – HPA induced changes – Microglial activation
Conclusions Potentially progressive Devastating Multimodal disease Worldwide economic and social burden
Effective intervention Fundamental differences in acute and chronic pain Effects on and by the neuromatrix biopsychosocial health of the individual patient Integrate a comprehensive multidisciplinary therapeutic plan
CSS Prognosis Guarded
The comorbidity of neuropsychiatric disease (depression, GAD, PTSD) and chronic pain are common.
When depression and chronic pain occur together, treatment success is dramatically lower and cost is dramatically higher than when these conditions occur separately.