San Diego Pain Summit: Through The Years

This is the first post in a three-part series about the San Diego Pain Summit.  You can find part two here and part three here (coming soon).  This initial post is a summary review of the San Diego Pain Summit Talks prior to 2023. My first time attending was in February 2023, so I decided to watch as many of the previous years' videos as possible in the months leading up to the event.  My brain still hurts. Many of the talks led me to read research papers and as I moved through the work, a beautiful web was created as many of these presenters have connections to other presenters. The pain neuroscience and pain management world, it seems, is far-reaching, and also quite small.  Having nearly completed watching all the previous videos, and most of the ones listed below  multiple times, I've compiled the most impactful pieces (in my opinion), organized into three themes: pain neuroscience, pain management, and special topics. You can watch any - or all - the previous San Diego Pain Summit recordings here.

I originally started watching videos from the San Diego Pain Summit in order to learn Pain Neuroscience. Yep... NERD ALERT! Lately there has been debate on social media about the utility of teaching pain neuroscience to patients. The theory was that if patients understood how pain worked, they might be better able to tolerate it and potentially even have reduction in symptoms.  I have read numerous books and written posts about them including Explain Pain and Explain Pain Supercharged in the past, but  I don't actually teach most patients pain neuroscience.  I do, however, find continued benefit as a clinician understanding the neuroscience so that I can better apply it to the interventions I'm choosing.  The level of scientific research presented was impressive, and I’d be lying if I said I understood all this work, but I took away many interesting pieces that inform my patient care.  

Pain Neuroscience

Let's start with animals. In the 2016 Summit, Dr. Robert Sapolsky’s lecture was not recorded, but he permitted his Q&A session to be shared.  Dr. Sapolsky is a Neuroendocrine Researcher who studies stress at Stanford University and who also examined behaviors of baboons and other animals in Africa.  For this he reminds me of my childhood hero, Jane Goodall, though she studied chimpanzees. He is the author of several books, including "Why Zebra’s Don’t Get Ulcers,” which I recently read, and he shares a fun anecdote about how zebras tend to be very social creatures with short memories of their stresses. A zebra could be running away from a lion and once it's free, quickly return to eating grass, seemingly not perseverating on its recent close encounter with a lion. Their stress levels don't persist the same way human stress levels do.  If I can't find my keys in the morning, it's going to keep my stress levels high through lunch time, much longer than the zebra who just avoided imminent death. Dr. Sapolsky describes social grooming - when animals groom one another, removing parasites and eating them off one another - and how this behavior is a stress reliever with associated decrease in heart rate and cortisol (stress hormone) levels.  He explains that each person's level of optimal stress varies from the person next to them. Cortisol, when sustained at elevated levels during a chronic stress state, can lead to illness.  

Dr. Jeffrey Mogil talks mice and rats

Then in 2017, Canadian Neuroscientist Dr. Jeffrey Mogil discussed his research in mice and rats and the concept of translation: conducting studies in animals with the intention of extrapolating information to humans. A big problem in scientific research was exposed because the majority of studies were conducted using either one type of mouse or one type of rat to generalize concepts to all humans.  There have been studies which show that different types of mice reacted differently to the same pain stimulus - so if some mice respond and others do not, the outcome of an experiment would be entirely dependent on which type of mouse was used in the study. This same problem occurs with sex - a single type of mouse, and only males of that type, were studied and then conclusions were applied to middle-aged women, but men and women are not the same! This, he explains, is how pharmaceutical companies could lose millions of dollars.  Testing done with success in a male rat and then later tested on a human woman would show medication that doesn't work and the drug will never make it to market.  At the time of his presentation, microglia: immune cells in the nervous system that impact development of brain networks, were a newer area of study in pain research.  It was determined that microglia might contribute to pain in males, but not in females, who may instead use t-cells: white blood cells of the immune system from stem cells in bone marrow. Women experience chronic pain more than males – doesn’t it seem plausible that the underlying processes may differ? Thanks to protections for human subjects in research, animal studies and use of translation are necessary to better understand the cellular level activities, but understanding the limitations of the work is also vital. I have a new appreciation for the value of rigorous research methods. 

Also in 2017, Dr. Melissa Farmer, Clinical Psychologist and Co-Founder/CEO of Aivo Health, shared her work based on animal models she created to represent some of the patients she had treated.  She talks about memory: the capacity to encode, store, retain, and recall information and engrams: the brain's physical changes that represent a memory. Memories induce changes in your brain and this doesn't occur in a single location, but rather it exists in a network throughout the brain. When you think back to a moment that makes you very happy, perhaps you can link together what you saw, the sensations on your skin, smells and sounds and even how you felt, all different brain areas mapped together from that event. You can also have these memory maps for pain. She described synaptic efficacy: a nervous system pathway becomes more efficient at transmitting information when it is repeated, so in the case of a person experiencing chronic pain, the brain pathways are being used repeatedly and become more efficient at experiencing pain. Memories are based on learning and she also describes a key retention window within the four hours following education where there is opportunity to enhance memory through various approaches such as caffeine or incorporating multiple senses. Her presentation also illuminates research from Dr. Apkurian's (below) lab indicating how the limbic system, the brain’s emotion center, is involved in chronic pain. Dr. Farmer demonstrates how fear can create a memory that can be reversed through training via a dramatic video of a patient overcoming his fear of tarantulas.  

Stages for Chronic Pain

Dr. Farmer works with Dr. Apkurian. In 2018, Physiologist  Dr. A. Vania Apkurian shared his research on the underlying genetic predisposition for chronic pain that can be activated by injury. This slide from his presentation shows that some patients have a genetic predisposition to chronic pain related to their limbic system that, when triggered by injury, would induce transition from acute to chronic pain. The limbic system is the "older" part of the brain which houses behavior and emotion - and this bridges research between animals and humans as mice show these limbic system changes with pain, too. Acute pain is different from chronic pain in the brain. The brain re-organizes when chronic pain occurs, specifically with cortical and emotional changes and these may be partially reversible. The brain changes appear to imitate patterns seen with addictions and may indicate that a person experiencing chronic pain is addicted to nociception: the sensory nervous system's reception of stimuli which are capable of inducing pain.

The 2019 Keynote Speech by Dr. Antonio Damasio, a Neuroscientist at University of Southern California was a great talk about emotions and feelings and how animals have emotive processes but not all animals possess a mind to experience the consequences of feeling those processes. Thanks to Google helping me better understand the terms with an article that quotes Dr. Damasio, emotion: "a brief episode of coordinated brain, autonomic, and behavioral changes that evoke a response to an event; these are a lower level response." and feelings: a higher level response which provide a mental and perceptual representation of what is physically happening inside our bodies."

His talk brings us farther away from animals and into the human experience of feelings and pain. He states, "All living creatures exist, act, and behave... all living creatures share the imperative of regulating their life processes (homeostasis) such that life can persist, flourish, and project itself into the future..." In some (single cell) animals, the nervous system is not necessary for homeostasis where endocrine, immune, and circulatory systems are sufficient. Many sea creatures do not have brains and are still capable of survival. Animals regulated life long before the nervous system evolved but once you have a nervous system, you can have a mind and regulate life in a novel (and better) way.  The nervous system allows us to be conscious of behaviors, provides a mind that analyzes emotions to interpret feelings as good or bad. I think I particularly connected to Dr. Damasio's talk because of his explanations for the physiological underlying features of how we have pain from emotions such as grief.  When a loss occurs, there are internal physiological processes (just like if you were physically injured) that occur and which can be expressed as pain. 

Brain regions in emotions, pain, and pleasure

Dr. Damasio shares these anatomy images of the subcortical brain and describes the role of various structures in emotions and also production of pleasure or pain. I already discussed that there is an emotional component to pain involving the limbic system - and the amygdala is part of that system, responsible for fear and involved in pain. The nucleus accumbens is involved with pleasure. And the hypothalamus runs the endocrine system which interacts with the other components. As we need a mind to have feelings, we also need it to have pain as it is an experience, not an anatomical feature of the body. 

Pain Management 

IASP Pain Classification Guidelines

Moving more into pain mechanisms and management  is the 2021 talk by Dr. Annie O’Connor, Founder of A World of Hurt, discussing nociception and pain classifications.  She shared the IASP Pain Classification Guidelines which are referred to in the more recent Summits as the definition of pain was updated in 2020. This paper, written by a task force including Dr. Mogil (above), and Dr. Kathleen Sluka (see part three of this series) describes the changes made from the 1979 definition to 2020 with important notes that clarify meaning. These categories of pain: nociceptive, nociplastic, and neuropathic pain are further discussed in part two of this blog series and are mentioned in several Pain Summit Presentations.  Having classifications for patients based on their underlying pain mechanisms is a fundamental start to pain management. 

So much science! Sorry, but I'm not sorry for rambling about all this amazingness.  I've always enjoyed using my blog as a place for me to organize my thoughts and what I'm learning and this was just such a huge undertaking… hence, three parts! I’m personally fascinated by the neuroscientists, and even more-so, I'm amazed by their knowledge and their willingness to share where the limits of our science exist.  Each talk includes a Q&A session and there were multiple questions where the research hasn't been done in that area yet and so the answers were unknown. That's really refreshing and demonstrates how (relatively) new a lot of this understanding is and why it's important for clinicians to learn and understand it more.  Interestingly, I don't really find this information to be very useful for my patients, particularly because most of my patients are teenagers. Even if they were adults, I'm not sure they would need to understand this to help improve their pain or quality of life. So how can I apply this knowledge to help patients feel better? Numerous therapeutic approaches have also been discussed throughout the Summits, and I won’t include them all here, but I will point out the ones that resonated most with me and which more directly impact my own patient care. 

New Zealand Occupational Therapist Dr. Bronnie Lenox Thompson’s 2016 talk described Motivational Interviewing (MI) as a communication structure for patient care to be a partnership based on clinicians guiding patients with compassion and by evoking motivation for them to pursue their own goals. She includes three related concepts: cognitive dissonance: inner drive to hold all of our beliefs in harmony, but when a patient's beliefs are contrary to our beliefs, we may have to act in a way that opposes what we believe. This is a conflict in our own thought practices as we think but act in opposing ways. Self perception theory: we like to behave according to what we say and believe. In this theory, our emotions are related to our actions and behaviors.  Interpersonal warmth: being a nice, warm, supportive, listening person to encourage others to go along with what we say.  With these concepts in mind, giving your patient autonomy in deciding how to improve their condition considering your guidance is an ideal therapeutic alliance approach. 

Alison Sim demonstrates CBT

In another 2016 talk that considers communication and a psychologically informed approach, Australian Osteopath Alison Sim presented about Cognitive Behavioral Therapy.  She uses a great example of burnt toast to demonstrate the different ways a person could react to this event with different thoughts, emotions, and behaviors.  In the first scenario, the person burns toast, thinks "bummer!" and maybe feels indifferent, following with the behavior of toasting another slice of bread.  As the emotions and thoughts escalate to more negative, you reach the final scenario where the toast is burnt, the thoughts are "even the toaster has it out for me" and the emotions are angry with behavior kicking the cat. (I think we're talking about feelings rather than emotions, here, but I'm not here to pick it apart.) Patients who are more distressed and disabled may need a more intensive program than CBT, so she reminds us to match our treatments to the patient in front of us. I just received Alison's book "Pain Heroes" and am looking forward to reading it!  

Social Communication Model of Pain

I'm a physical therapist who STRONGLY believes that the words we use with our patients matter and that communication and therapeutic alliance are essential skills for optimal care. I particularly liked this quote from Physical Therapist and University of Florida Clinical Associate Professor Dr. Joel Bialosky’s 2022 presentation quoting Wambold 2017, “Some therapists consistently achieve better outcomes with patients than other therapists – and these differences are not due to random error, patient characteristics, or other systematic sources of error.” The amount of an observed outcome is attributed to something inherent to the therapist. Therapeutic Alliance is repeatedly mentioned in talks.  It comes up in Physio, Consultant, and Mentor Dr. Devra Joy Sheldon's 2020 talk along with the Social Communication Model of Pain, reminding us of the importance of social contributors to reduce shame in pain management and that we are inextricably linked to our patients' pain experiences. Also in 2022, David Poulter presents his talk about therapeutic alliance and patient-centered care, which come up in several other talks over the years and repeatedly reinforces the importance of clinician and patient relationships. He reminds us that We need to change before our patients can change. 

You may notice that nothing I've mentioned has been physical yet. And I'm a physical therapist. The Pain Summit includes occupational therapists, massage therapists, chiropractors, mental health providers, physicians, and patients as attendees, so the talks cover many different perspectives.  All the providers would need to move beyond communication and into their specialized interventions.  In 2017, Cor-Kinetic Owner and Physio Ben Cormack from London talked about exercise and movement. The numerous benefits of exercise - like improved respiration and cardiovascular endurance, increased strength, and reduction in pain, are all discussed. He describes the need to guide patients so they transfer from an external to an internal locus of control and help them to form new memories that are positive instead of the negative pain memories they've associated with movement. In 2018, Canadian Biomechanist, Physio, Chiro, and Strength and Conditioning Specialist Greg Lehman shared "When Biomechanics Doesn't Matter." These guys are really great presenters, but it's probably harder to make neuroscience funny where it's a bit easier to make exercise a bit comical.  Both of them demonstrate that specific exercises like the ones we frequently provide in physical therapy practice aren’t the necessary target for intervention – but more so getting patients to participate in the activities that bring them joy is a more optimal approach. I've previously written about Dr. Lehman's "Reconciling Pain Science and Biomechanics" course and here he negates numerous concepts learned in PT School about movement patterns and biomechanics that research does not support. It’s not that form and posture and movement patterns never matter, it’s just that for the general population, most of the time it is unlikely to be the driver of pain.  So yes, exercise is helpful for management of chronic pain.  The exercise probably doesn't need to be specific and is one piece of a more complicated puzzle. 

Body-Wide Symptoms of Long Covid

Which brings me to the special topics. I think these are really important and deserve far more attention than I’m providing here, but for my 12 subscribers to this blog, they’re key considerations for patient care. First, the 2022 talk by Physio and Athletic Trainer Dr. Daria Oller and also presentation from Physio and Professor at University of the Pacific Dr. Todd Davenport regarding Long Covid, Post Exertional Malaise, Myalgic Encephalitis, Autonomic Dysfunction, and Chronic Fatigue Syndrome are essential viewing for anyone treating patients with these diagnoses.  Dr. Oller and Dr. Davenport are both involved in Long Covid Physio which is an incredible resource for patients and clinicians. Our typical approach using progressive overload exercise for patient care is contraindicated for these patients and we need to spread the word that a pacing approach is indicated, otherwise you are doing harm.  It’s incredibly likely that if you are a physical therapist, you’re going to have a patient with post viral illness or chronic fatigue, even if it isn't Long Covid.  Take the time to watch these talks so you can be better informed.

And last, but very certainly not least, I encourage all healthcare providers to watch the 2022 talk from Dr. Lisa VanHoose entitled "Your Pain Evaluation Is Incomplete Without a Zip Code Assessment." where she goes into great detail about your personal biases and how zip code data can give you a lot of context and is easy to get.  This link (after you scroll down to "Discover the Power of Data") gives you the chance to enter a zip code and see numerous data points including household income, cost for medical insurance, how many people live in that neighborhood, diversity, and demographics. The data will be presented as averages and needs to be confirmed along with the story from the patient in front of you.  Understand that two patients could live a mile away from each other, and one have limited access to medical care, physicians, pharmacies, schools, green spaces, public transportation, grocery stores, and more – all of which impact their lived experienced and their health.  If you can't watch the full hour of her talk or you're not convinced, here's the five minute video "A tale of two zip codes" Dr. VanHoose shared that starts you thinking.  I found this talk eye opening and highly recommend it.

There were so many additional excellent speakers, many of whom I’ve gotten to know in some capacity, others who are juggernauts in the field. Some of the topics, such as pelvic health, are incredibly important but are a very small percentage of my patient population, so I couldn't relay the important pieces from those talks in a way that would help others. If you're working with patients experiencing chronic pelvic pain, I highly encourage you to go to the Pain Summit YouTube Page and check out the videos there. Other talks stood alone like the presentation from Dr. Sandy Hilton and Dr. Mark Milligan on clinician burnout, which is a really important topic and relevant, but is less specific to patient care.  I had to draw a few lines, and it left out amazing speakers. I’m sorry to leave everyone else out of this post.  Your work and your knowledge have impacted me, and I’m so grateful.  

Stay tuned for Part Two coming soon!