Altered Body Perception in Stroke Survivors with Chronic Pain

PainRelief.com Interview with:
Dr Brendon Haslam PhD
La Trobe University and The Florey Institute of Neuroscience and Mental Health
University of Melbourne
On behalf of the research team that is a collaboration of researchers from the University of South Australia, La Trobe University, University of Melbourne and University of California, San Francisco

Dr Haslam PhD

PainRelief.com: What is the background for this study?

Response: People who experience a stroke are three times more likely to experience chronic pain than the general population. Chronic pain following stroke has additional impact on stroke survivors, making it even harder for them to carry out everyday tasks related to their personal care, occupational and recreational activities. As a result, stroke survivors with chronic pain suffer additional disorders of mood, including depression, that further reduce their quality of life beyond that that is caused by the stroke itself.

Unfortunately, there is currently very little evidence to show effective treatments for stroke survivors with chronic pain. This includes the use of medications and other health therapies. In looking to understand chronic pain following stroke, and be able to develop new therapy approaches for this population, we explored how stroke survivors with and without pain perceive their own bodies. For this study, we particularly explored how they perceived their hand size to be.

Chronic Pain Linked to Later Life Pessimism and Joblessness

PainRelief.com Interview with:
Alex Bryson PhD
Professor of Quantitative Social Science
UCL Social Research Institute
University College London  London

Prof. Bryson

PainRelief.com: What is the background for this study?

Response: The authors were concerned to know more about both the incidence of chronic pain and its implications for health, wellbeing and labour market prospects later in life.  So we turned to a birth cohort study (The National Child Development Study) tracking all those born in Britain in a single week in 1958 through to age 62 to take a life-course approach.

iovera° Cryoneurolysis Treatment is Drug-Free Option for Knee Pain

PainRelief.com Interview with:
Vinod Dasa MD
Professor of Clinical Orthopaedics
Director of Research
Louisiana State University Health

PainRelief.com:  Would you describe cryoneurolysis?

Response: Cryoneurolysis is a specialized intense cold therapy technique that provides long-term pain relief without the use of any system drugs. The iovera° system has revolutionized the delivery of long term, drug-free pain relief by delivering a concentrated, targeted cold therapy through a handheld device. The iovera° treatment blocks targeted sensory nerves from sending pain signals. Small closed-end needles are inserted into the treatment region and a treatment cycle is performed until the nerve is blocked, providing pain relief until the nerve regenerates. The localized nerve blocks and targets peripheral nerves to temporarily stop pain signals for up to 90 days and provide immediate, long-lasting pain relief without the need for opioids. The iovera° treatment is used to treat specific nerves so the pain relief is focused only on the part of the body that is being treated.

University of Pittsburgh Study Finds Durable Pain Relief in Obese Patients Following Bariatric Surgery

PainRelief.com Interview with:
Wendy C. King, PhD
Epidemiology Data Center
School of Public Health
University of Pittsburgh
Pittsburgh, PA

Dr. King

PainRelief.com: What is the background for this study?

Response: Previous studies had provided evidence that bariatric surgical procedures are associated with improvements in pain, physical function and work productivity. However, most prior studies only followed participants 1-2 years, at which point participants were at the peak of their weight loss. 

Among a large cohort of US adults, we wanted to evaluate how much initial improvements in pain, physical function and work productivity declined during long-term follow-up, when some degree of weight regain is not uncommon. We limited our study to adults who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG), the two most common bariatric surgical procedures done today.

Review of Lidocaine Infusions for Pain Relief from Chronic Migraine

PainRelief.com Interview with:
Eric C. Schwenk MD
Anesthesiology
Sidney Kimmel Medical College
Thomas Jefferson University
Philadelphia, Pennsylvania

Dr. Schwent

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: Patients with refractory chronic migraine (rCM) have typically failed all available medications and many times have nearly constant headache pain and in many cases disability. Aggressive treatment is indicated to provide relief and help break the cycle of pain.

Lidocaine infusions have been used for decades in various acute and chronic pain conditions, including complex regional pain syndrome and pain after surgery. At the Jefferson Headache Center lidocaine has been a mainstay of treatment for such patients for several decades but evidence supporting its benefits is scarce.

The main findings were that patients with rCM experienced acute relief at the end of the infusion and that some relief was sustained at 1 month, although the degree of pain relief faded over time. It was also well tolerated with nausea and vomiting occurring in 16.6% of patients and other side effects occurring less frequently.

Chronic Pain: Sex Differences in Pain Relief from High vs Low Spinal Cord Stimulation

PainRelief.com Interview with:
Imanuel Lerman MD MSc
Associate Professor 
Affiliate Electrical and Computer Engineering 
VA San Diego Healthcare System
Center for Stress and Mental Health
Center for Pain Medicine 
UC San Diego Health 
Qualcomm Institute 
California Institute for Telecommunications and Information Technology (Calit2)

Dr. Lerman

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: Spinal Cord Stimulation (SCS) offers an implantable, non-pharmacologic treatment for patients with intractable chronic pain conditions.  There is extensive clinical literature that offers support for efficacy in chronic pain treatment for both Low frequency and High frequency based  spinal cord stimulation. While Low Frequency SCS has been heavily examined since its inception, High Frequency SCS paradigms have recently been clinically approved.

Emerging preclinical work also show sex may alter certain immunological pathways that contribute to chronic pain.  But to date few report have identified interactions between sex and SCS.  Therefore, we aimed to fill this knowledge gap through a single site (University of California San Diego), large (n=237) retrospective (2004–2020) analyses that compared SCS paradigm Low vs High Frequency SCS, efficacy (pain relief and opiate sparing effects) across sex.

Psychological Interventions For Non-Specific Chronic Low Back Pain

PainRelief.com Interview with:

Ms Emma Ho | BAppSc(Phty)(Hons), PhD Candidate
The University of Sydney                                          
Faculty of Medicine and Health | Charles Perkins Centre Musculoskeletal Research Hub | Sydney NeuroMusculoskeletal Research Collaborative
Faculty of Medicine and Health, The Back Pain Research Team, Sydney Musculoskeletal Health, The Kolling Institute, School of Health Sciences

Emma Ho

PainRelief.com:  What is the background for this study? 

Response: Adults with chronic low back pain (lasting for more than 12 weeks) not only experience physical disability but can also suffer psychological distress in the form of anxiety, depression, and fear avoidance (avoiding movement for fear of pain).

Clinical guidelines therefore consistently recommend a combination of exercise and psychosocial therapies for managing chronic low back pain. However, not much is known about the different types of psychological therapies available as well as their comparative effectiveness and safety, leaving doctors and patients often unclear about the best choice of treatment. Accordingly, the aim of our systematic review with network meta-analysis was to determine the comparative effectiveness and safety of psychological interventions for chronic non-specific low back pain.

Study Identify Mechanism That Converts Normal to Chronic Pain

PainRelief.com Interview with:
Dr. Daniela Mauceri PH.D.
Neurobiology
Heidelberg University
Heidelberg Germany

PainRelief.com:  What is the background for this study? 

Response: Physiological, normal, pain prevents damage to the tissues and, in case of injury, resolves with healing. Pathological, chronic pain however, will persist after injury is mended and can manifest even in absence of causes. The transition from physiological to chronic pain is sustained by alterations of gene expression in the cell belonging to the pain circuitry such as neurons of the dorsal horn spinal cord. Epigenetic changes are important mechanisms regulating gene transcription in mammalian cells and had been previously implicated in pain chronification. A detailed understanding of which epigenetic mechanism would be critical in the establishment of chronic pain was still missing and the identity of the regulated genes still elusive.


PainRelief.com:  What are the main findings?

Response: In our study we described how one particular epigenetic molecule named Histone Deacetylase 4 (HDAC4) is inactivated in the neurons of the dorsal horn spinal cord in persistent inflammatory pain. We also showed that inactivation of HDAC4 leads to increased expression of Organic Anion Transporter 1 (OAT1) and found that OAT1 is responsible for the mechanical hypersensitivity typical of chronic pain. 

PainRelief.com: What should readers take away from your report?

Response: Our study suggests that finding ways to maintain HDAC4 in an active state might prevent pain chronification by blunting the upregulation of OAT1. Alternatively, blocking OAT1 activity with a pharmacological approach might also be beneficial.

PainRelief.com: What recommendations do you have for future research as a result of this work?

Response: Chronic pain is a severe pathological condition affecting a considerable part of the worldwide population. Treatments are still unsatisfactory. Our study, although performed using a mouse model of chronic inflammatory pain puts forward two potential new candidates (HDAC4, OAT1) for not only future investigations but also, importantly, for the development of future therapeutic approaches.

The research work was funded by the CRC1158 on Chronic Pain by the German Research Foundation.

Citation:

Litke, C., Hagenston, A.M., Kenkel, AK. et al. Organic anion transporter 1 is an HDAC4-regulated mediator of nociceptive hypersensitivity in mice. Nat Commun 13875 (2022). https://doi.org/10.1038/s41467-022-28357-x

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Study Evaluates Complex Relationship Between Eating and Chronic Pain

PainRelief.com Interview with:
Paul Geha, M.D
Assistant Professor of Psychiatry
University of Rochester Medical Center
Rochester, NY 14620

Dr. Geha

PainRelief.com:  What is the background for this study? 

Response: Chronic pain and obesity are interrelated; chronic pain is more common in obese individuals and obese individuals have a higher occurrence of chronic pain conditions such as low-back pain.  The mechanisms behind this association are poorly understood.  In this line of work we are trying to offer an explanation for how chronic pain could lead to obesity. 

We build on two previous facts established in the literature to come up with a new theory. 

First, it is well known that the current obesity epidemic is due to overeating in an environment where highly caloric food is cheap and readily available (e.g., fast food).

Second, our brain imaging research on chronic pain patients established that chronic pain affects the brain motivational pathways (or emotional brain) which are directly involved in feeding decisions, especially the ones that come after satiety.  As such, the emotional brain has been implicated in the decision to overeat on top of satiety. We therefore hypothesized that chronic pain would be associated with disrupted eating behavior that could lead to overeating because of changes in the emotional brain of patients. This is a new approach because the prior thinking posited that obesity and chronic pain are interrelated either because of increased inflammation originating from the increased fat mass or from the fear of movement that patients may have leading to a more sedentary lifestyle. While both theories may be correct, they have never been confirmed.

The current paper builds on a finding we published in PAIN 2014 where we established disrupted eating behavior in patients with chronic low-back pain affecting mainly high-fat foods but not sugary drinks.  In that work we asked patients with long-standing history of chronic low-back pain to sample without consumption pudding with increasing concentration of fat and a sugary drink with increasing concentration of sucrose.  While the sensory experience of the food items was normal in the patients, they reported less pleasure (“liking”) from tasting the fatty pudding but not the sugary drink. On a different session, we brought back the patients and offered them to consume as much as they wanted the pudding that they liked the most during the first testing session. Participants were asked to come hungry.   Chronic back-pain patients showed that their liking and hunger ratings did not predict how much they ate.  Healthy controls showed a linear relationship between liking and hunger ratings and how much they ate. 

In the manuscript we just published in PLOS One we continued this line of work to understand how this disrupted eating behavior sets in as low-back pain develops or subsides.  We wanted to know whether disrupted eating behavior develops in conjunction with chronic pain or because of it.  Hence, we recruited patients with new onset low-back pain (6-12 weeks duration) and tested them in the same way described in our PAIN 2014 paper at baseline and then again at one year as some of them recovered from pain while others became chronic low-back pain because pain persisted at one year follow-up.  In this manuscript we also collected brain images that would allow-us to measure volumes of a key structure in the emotional brain, the nucleus accumbens.  The function of the latter structure is to translate our motivation (e.g., wanting to eat) to actions (e.g. the motor response needed to reach for the food). We wanted to know whether we can link the disrupted eating behavior to measures in the emotional brain. This question was based on our previous finding where we observed that patients at risk of becoming chronic pain or patients already in the chronic phase have a compromised accumbens (i.e. smaller than normal).

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As Opioid Prescriptions Fall, Alternate Prescriptions for Pain Relief Increase

PainRelief.com Interview with:
Lauren R. Gorfinkel MPH
New York State Psychiatric Institute
New York, NY
Department of Medicine, University of British Columbia
Vancouver, Canada

PainRelief.com:  What is the background for this study? 

Response: The opioid crisis has led to clear declines in opioid prescribing across North America, however, chronic pain remains an extremely common health problem with limited treatment options. This study was therefore interested in using nationally-representative data to find out whether alternative pain medications are growing more popular as opioid prescriptions decline.