tai chi for knee OA; mindfulness for chronic pain

1. A recent study found that Tai Chi was at least as good, and sometimes better, than physical therapy (PT) for patients with painful knee osteoarthritis, OA (see knee arthritis tai chi vs PT AIM2016​ in dropbox, or doi:10.7326/M15-2143). There have been some earlier studies finding efficacy of Tai Chi for knee osteoarthritis, rheumatoid arthritis, and fibromyalgia, by decreasing pain and improving physical and psychological health. The current study compared Tai Chi with PT. details:

--204 people with symptomatic knee OA

--mean age 60, 70% women,  53% white/35% black, BMI 33, duration of knee pain 8 years, mostly moderate radiologic OA (Kellgren-Lawrence grade 2 in 38%, 3 in 37%), 50% hypertensive, 20% diabetic, mean WOMAC pain score (Western Ontario and McMaster Universities Osteoarthritis Index) 253 (range 0-500)

--interventions (patients allowed to continue meds, including acetaminophen and NSAIDs):

                --Tai Chi: 60 minute sessions 2x/week for 12 weeks.  Explanation of mind-body exercise theory and procedures. Patients instructed to do home Tai Chi at least 20 min/d (videotaped with feedback throughout the study). At end of 12 weeks, patients asked to continue at home for the duration of the study

                --PT: 30 minute sessions 2x/week for 6 weeks. Individual assessment and targeted regimens. Exercise at home. At end of 6 weeks, patient asked to continue with 30-minute sessions 4 x/week for 6 weeks. [ie, shorter intervention than Tai Chi, but this is a standard PT regimen]

--results (with 52 week follow-up)

                --overall attendance: 74% for Tai Chi and 81% for PT 

                --clinical outcomes (WOMAC pain, physical function and stiffness scores; patient global assessment score; Beck depression inventory;  SF-36,  a health survey; arthritis self-efficacy score; and both the 6-minute and 20-minute walk scores): patients in each group showed improvement over time, including at 52 weeks, well after the active interventions. But, comparing the interventions: Tai Chi was better than PT for essentially every outcome and at weeks 12, 24 and 52. However, the difference was statistically significant only for the physical component of SF-36 and Beck depression inventory.

                --use of NSAIDs and analgesics: also generally less with Tai Chi, but not reach statistical significance.

Commentary:

--this was perhaps a somewhat unexpected finding since the focus of PT is so different from Tai Chi. PT largely involves stretching and strengthening exercises and some local therapies, leading to improved quadriceps dynamics in particular, developing increased support for the knee and decreasing the load on the joint itself (at least that is my understanding. Studies have shown that quadriceps weakness correlates with the degree of knee pain). Tai Chi combines meditation, slow and gentle movements, deep diaphragmatic breathing and relaxation (ie, physical as well as psychosocial/emotional/behavioral elements).

--in this study on Tai Chi, it is impressive that the results remained pretty consistent at 12, 24, 52 weeks. My guess is that the Tai Chi group did continue their home-based exercises after the formal study stopped (data not in article), but either way, that suggests that the benefits are durable (and perhaps Tai Chi really can be incorporated into one's life longterm)

2. A complementary article appeared near the same time in JAMA, stressing a role for mindfulness meditation in pain management (see chronic pain mindfulness JAMA 2016​ in "chronic pain" folder in dropbox, or doi:10.1001/jama.2016.4875). briefly, mindfulness meditation involves an increasing awareness of body sensations (eg breathing), techniques to promote mindful practice (yoga, meditation), learning how to understand and change how we react to stress, understanding the relationship between stress and pain, and viewing the reactions to stress without judgment.   this JAMA Perspective highlights some pretty impressive studies:

--a randomized controlled trial showing that mindfulness-based stress reduction (MSBR) was comparable to ​cognitive behavioral therapy (CBT) in reducing chronic low back pain, finding that there was no difference between MBSR and cognitive behavioral therapy (CBT), both with about a 45% reduction in pain (vs 25% with usual care). for my review of full article, see prior blog: http://gmodestmedblogs.blogspot.com/2016/03/low-back-pain-improves-with-stress.html 

--another RCT involved 282 older adults with chronic low back pain, also finding that those with 8 weeks of mindfulness meditation followed by 6 monthly sessions showing that 45% of the patients experienced >30% reduction in pain vs 25% of the patients in the control group.

--using functional magnetic resonance imaging of volunteers exposed to a noxious stimulus, those who practiced mindfulness meditation had a 57% decrease in how unpleasant the stimulus felt and a 40% decreased rating of pain intensity vs control (and those who paid attention just to breathing did not have these benefits). they found that meditation was associated with more activation of the orbitofrontal cortex (OFC), an area of the brain which "controls how people put into context what they sense in the environment". Subjects commented that they did in fact feel the pain but were able to "let it go" and not dwell on it. the meditation also led to less activation of the thalamus, which serves as the pain gateway from the spinal cord to the brain, and activation of the anterior cingulate cortex (ACC), involved in cognitive control and emotional regulation. And, interestingly enough, though there are plenty of opioid receptors in the OFC and ACC, mindfulness did not affect these receptors (naloxone had no effect).

Overall Commentary:

--these articles reinforce the intimate connection between pain perception and one's psychosocial state.

--there seems to be a shift in thinking about chronic vs acute pain, with argument that the issue with chronic pain involves different/more extensive central involvement (hyperalgesia, changes in functional neuroimaging, more somatic symptoms such as fatigue, memory problems, insomnia, mood disorders), which supports the use of different CNS-directed treatments (SNRIs, anticonvulsants) -- for more info see chronic pain central mechanism best prac rheum2011 in "chronic pain" folder in dropbox, or Phillips K. Best Pract Res Clin Rheumatol 2011; 25: 141.

--those with chronic pain often have increased response to peripheral stimuli (hyperalgesia/allodynia), rate pain as more severe, and those with chronic widespread pain often have specific focal triggers, such as myofascial trigger points, ligamentous trigger points, or osteoarthritis of the spine or joints. And these focal triggers can lead to/perpetuate the chronic pain (see chronic pain peripheral pain mech rheum2011 in "chronic pain" folder in dropbox, or Staud R. Best Pract Res Clin Rheumatol 2011; 25: 155.)​ This ties together the complex interaction between peripheral triggers/local changes (eg increased lactic acid production, cytokines) and the central interpretation of that pain, including the sensation of chronic widespread pain.​ (it is really common for a patient with a particularly painful local site to have much more diffuse bodily pain. in my experience, I have sometimes been able to treat the triggering source with injections, leading to a generalized decrease in pain overall).

--also, it is pretty clear that stress itself may be a bad actor: stress leads to muscle tightness (perhaps part of the fight/flight response and readiness to act). but chronic stress leads to chronic muscle tightness and pain transmitted largely through the the spinothalamic tract pain fibers to the thalamus/ACC/etc and then to the cerebral primary somatic sensory cortex. as noted above, several of these processing stations alter their pain response by meditation. 

--in terms of the peripheral musculoskeletal effects of chronic stress, it seems to me that there are certain areas of muscle tightness that are more common with chronic stress, such as at the occipital insertion of the trapezius, diffusely in the muscles around the cranium/tension headaches, costochondral areas in the sternum, lower back, and several of the "trigger points" of fibromyalgia.)

--to me, the above studies suggest a couple of things:

    --decreasing the functional impact of stressors, whether through mindfulness meditation, Tai Chi or CBT, can decrease the direct effects of stress on the muscles (and there is the argument that many people with chronic pain "catastrophize" it: thinking negative thoughts about how pain will affect their function, which might expectantly exacerbate pain sensation. these psychological techniques directly affect how stress is perceived and handled)

    ​--and, there are impressive data that there are also meditation affects on how various parts of the brain itself (thalamus, anterior cingulate cortex, etc) fundamentally respond to painful stimuli

--the CDC stresses that the preferred therapy for pain management is maximizing nonpharmacologic and nonopioid pharmacologic pain management (see http://gmodestmedblogs.blogspot.com/2016/03/new-cdc-guidelines-for-opiate.html for review)

--so, whether the beneficial effect of mindful meditation, CBT or Tai Chi is through moderating the perception of stress or the changing the way pain is handled centrally, or both (hard to separate), it seems to me to be increasingly clear that there are some important and perhaps fundamental differences in how patients with chronic pain experience their pain, and that we should be more aggressively pursuing a more global approach, including mindfulness meditation, Tai Chi, or CBT as a really important nonpharmacologic component to helping people with chronic pain. this approach coincides with the CDC focus on maximizing nonpharmacologic adjunctive therapies as a way to avoid opiates or at least minimize their use (in this context, it is intriguing that the above alterations in central pain pathways by mindfulness meditation do not seem to be entirely related to opiate receptors, both suggesting that either endogenous or exogenous opiates may not be necessary for effective chronic pain management and that there may be room for development of other, nonopiate meds as part of chronic pain treatment...