Manual Therapy: Manipulation of the Brain?

by Tara Winters PT, DPT

When a person walks into the clinic with low back pain with primary nociplastic pain mechanisms, I’m armed and ready with a number of treatment ideas. This is thanks to the leaps and bounds made in the last 20 to 30 years in the world of pain science. “Let’s see if you can distinguish this photo of a right hand versus a left hand”, “I’m going to create a quadrant on your lower back and I want you to tell me which quadrant you feel pressure in”, “Let me tell you about the science behind your pain!”. We then find ourselves down this (evidence-based, of course) rabbit hole of treatments, termed graded motor imagery (GMI), with manual therapy falling lower on our list of treatment needs. Can you relate?

What we know about pain today is incredible and ever fascinating. Understanding that persistent pain can lead to altered central processing, disorganized sensory and motor information, and a diffuse increase in peripheral sensitivity has helped us treat this complex condition in novel ways.^1,2,3 GMI and other forms of treatments alike can absolutely contribute to impactful changes in people’s lives. However, as I make my way through my manual therapy fellowship program, I can’t help but wonder if we’ve swayed too far in one direction. I fear that we may be moving away from person-centered care and putting those with persistent, dominant nociplastic pain mechanisms into a box.

Lately, therapists seem to be using manual therapy less frequently due to the concern with passivity, dependency, and lack of supporting evidence in those with persistent pain to justify its effectiveness.⁹ I want to challenge and explore this concept. There is actually little to no high quality research to support manual therapy as “low value” care. In fact, we see quite the opposite. Used for hundreds of years, manual therapy is a treatment technique that Bishop et al proposes “encompasses a philosophy of caring for the patient” with effects that range from simple to complex.⁴

Early research gave us an understanding of the biophysiological, mechanistic effects of manual therapy interventions. Patients experience a reduction in pain and improvement in motion secondary to the alteration in surrounding inflammatory mediators.^5,6 In addition to localized effects, manual therapy has global influences on hormone and neurotransmitter production.⁴ Techniques can increase serum levels of dopamine, serotonin and endocannabinoids thus impacting pain processing.⁴ Due to the neurophysiological underpinnings associated with nociplastic pain, these and other central nervous system effects are of importance to note.⁸

Our knowledge continues to evolve on the more complex, supraspinal side of things. Manual therapy reduces temporal summation and nociceptive flexion reflexes, therefore affecting nociceptive input in the central nervous system.^5,6 Reduction in insular cortex activity and connectivity between brain regions, all of which were associated with subjective reports of pain reduction, have been seen with the use of fMRI testing in human subjects following manual therapy interventions.^5,6 By the way, this was not necessarily technique specific. Many of these mechanistic effects occur despite the technique (manipulation, mobilization, soft tissue mobilization).^5,6

Hopefully by this point, we can appreciate the myriad of effects of manual therapy. Now, how can this apply clinically? Should we use GMI, manual therapy, exercise, or pain neuroscience education for people with persistent pain?

First, consider the dominant pain mechanism. If a person presents with nociceptive pain, we can use different types of manual therapy to create a window of time where the person can move better and work toward their goals. People with nociplastic pain can benefit from similar logic and clinical reasoning. We can use manual therapy techniques such as joint and soft tissue mobilization when appropriate. We can also use manual therapy in conjunction with GMI. Manual therapy does not have to be an isolated, passive treatment, nor does it have to revolve around local stimulation to the joints or soft tissue. Manual therapy is meant to stimulate the peripheral and central nervous system. When we apply sensation to a person’s unaffected limb during mirror therapy or apply varied pressures during sensory discrimination training, we stimulate the neurophysiological mechanisms mentioned above.^4,5,6,8 Understanding the current evidence surrounding both of these modalities, along with the current knowledge surrounding nociplastic pain mechanisms, allows us to best discern when to integrate these treatment strategies.

The other consideration we must factor into our clinical decision making process is a person’s expectations. Our evaluations should include inquiries into the person’s hopes and expectations in working together. Many patients want and expect manual therapy.⁴ Understanding this early can help guide our treatment selection. Overall, interpreting and acting on patient expectations is arguably the most important factor in determining which interventions will dominate our treatment sessions and lead to optimal outcomes.

Physical therapists are in a unique position in which we can provide therapeutic touch, novel perspectives on pain, and stellar exercise prescription. This sets us apart. I urge you to understand the current research, leverage tools that you find effective and are in the best interest of the patient, and maintain curiosity and open-mindedness. This is, truly, a person-centered approach to treating persistent pain.

References:

1. Winkelstein BA. Mechanisms of central sensitization, neuroimmunology & injury biomechanics in persistent pain: implications for musculoskeletal disorders. J Electromyogr Kinesiol. 2004 Feb;14(1):87-93. doi: 10.1016/j.jelekin.2003.09.017. PMID: 14759754.
2. Latremoliere A, Woolf CJ. Central sensitization: a generator of pain hypersensitivity by central neural plasticity. J Pain. 2009 Sep;10(9):895-926. doi: 10.1016/j.jpain.2009.06.012. PMID: 19712899; PMCID: PMC2750819.
3. Thomas Cheng H. Spinal cord mechanisms of chronic pain and clinical implications. Curr Pain Headache Rep. 2010 Jun;14(3):213-20. doi: 10.1007/s11916-010-0111-0. PMID: 20461476; PMCID: PMC3155807.
4. Bishop MD, Torres-Cueco R, Gay CW, Lluch-Girbés E, Beneciuk JM, Bialosky JE. What effect can manual therapy have on a patient’s pain experience? Pain Manag. 2015;5(6):455-64. doi: 10.2217/pmt.15.39. Epub 2015 Sep 24. PMID: 26401979; PMCID: PMC4976880.
5. Bialosky JE, Beneciuk JM, Bishop MD, Coronado RA, Penza CW, Simon CB, George SZ. Unraveling the Mechanisms of Manual Therapy: Modeling an Approach. J Orthop Sports Phys Ther. 2018 Jan;48(1):8-18. doi: 10.2519/jospt.2018.7476. Epub 2017 Oct 15. PMID: 29034802.
6. Bialosky JE, Bishop MD, Price DD, Robinson ME, George SZ. The mechanisms of manual therapy in the treatment of musculoskeletal pain: a comprehensive model. Man Ther. 2009 Oct;14(5):531-8. doi: 10.1016/j.math.2008.09.001. Epub 2008 Nov 21. PMID: 19027342; PMCID: PMC2775050.
7. Coulter ID, Crawford C, Hurwitz EL, Vernon H, Khorsan R, Suttorp Booth M, Herman PM. Manipulation and mobilization for treating chronic low back pain: a systematic review and meta-analysis. Spine J. 2018 May;18(5):866-879. doi: 10.1016/j.spinee.2018.01.013. Epub 2018 Jan 31. PMID: 29371112; PMCID: PMC6020029.
8. Fitzcharles MA, Cohen SP, Clauw DJ, Littlejohn G, Usui C, Häuser W. Nociplastic pain: towards an understanding of prevalent pain conditions. Lancet. 2021 May 29;397(10289):2098-2110. doi: 10.1016/S0140-6736(21)00392-5. PMID: 34062144.
9. Mintken PE, Rodeghero J, Cleland JA. Manual therapists – Have you lost that loving feeling?! J Man Manip Ther. 2018 May;26(2):53-54. doi: 10.1080/10669817.2018.1447185. Epub 2018 Mar 26. PMID: 29686478; PMCID: PMC5901426.