Sunday, January 14, 2007

Adrenal Cells and Pain

Kevin McHenry's latest blog is on chomaffin cells and the relationship they may have to reducing pain. In there he mentions their "strange affinity" with neurons. He marvels that with the addition of "a little acid", chromaffin cells can be made to turn into neurons.

Perhaps this is not so strange when we remember that they are close relatives, coming as they do, embryologically, from neural crest. Anything made after mesenchyme splits off (to make mesodermal derivatives like bone, muscle, joints, connective tissue, which create structural support for an organism and use way less oxygen) ... anything made after the mesenchymal layer splits off is likely to have a higher "access code" to the nervous system proper than anything mesodermal, and enjoy a closer relationship.

Neural crest makes the entire peripheral nervous system - not motor axons, but all the sensory neurons including dorsal root ganglia, and all sympathetic nervous system related structures like chromaffin cells.

Sunday, January 07, 2007

Hands on Heads

I have submitted this piece to the CPPSG (Canadian Physiotherapy Pain Sciences Group) for inclusion into the next newsletter:

What is truly happening when we put our hands on heads, and slide scalp over bone?

DOI: 10.2519/jospt.2006.2278
November 2006 Vol.36 No.11
Craniosacral Therapy: The Effects of Cranial Manipulation on Intracranial Pressure and Cranial Bone Movement
• Patricia A. Downey, PT, PhD, OCS, Associate Professor, Physical Therapy Program, Chatham College, Pittsburgh, PA
• Timothy Barbano, BDS, MS, DMD, Research Specialist II, Department of Anthropology, University of Pittsburgh, Pittsburgh, PA
• Rupali Kapur-Wadhwa, BDS, MS, DMD, Assistant Professor, Department of Orthodontics and Dentofacial Orthopedics, University of Pittsburgh, Pittsburgh, PA
• James J. Sciote, DDS, MS, PhD, Associate Professor and Chair, Department of Orthodontics and Dentofacial Orthopedics, University of Pittsburgh, Pittsburgh, PA
• Michael I. Siegel, PhD, Professor, Departments of Anthropology and Orthodontics, University of Pittsburgh, Pittsburgh, PA
• Mark P. Mooney, PhD, Professor, Departments of Oral Medicine and Pathology, Anthropology, Surgery Division of Plastic and Reconstructive Surgery, and Orthodontics, University of Pittsburgh, Pittsburgh, PA

Study Design: Quasi-experimental design.

Objectives: To determine if physical manipulation of the cranial vault sutures will result in changes of the intracranial pressure (ICP) along with movement at the coronal suture.

Background: Craniosacral therapy is used to treat conditions ranging from headache pain to developmental disabilities. However, the biological premise for this technique has been theorized but not substantiated in the literature.

Methods: Thirteen adult New Zealand white rabbits (oryctolagus cuniculus) were anesthetized and microplates were attached on either side of the coronal suture. Epidural ICP measurements were made using a NeuroMonitor transducer. Distractive loads of 5, 10, 15, and 20 g (simulating a craniosacral frontal lift technique) were applied sequentially across the coronal suture. Baseline and distraction radiographs and ICP were obtained. One animal underwent additional distractive loads between 100 and 10 000 g. Plate separation was measured using a digital caliper from the radiographs. Two-way analysis of variance was used to assess significant differences in ICP and suture movement.

Results: No significant differences were noted between baseline and distraction suture separation (F = 0.045; P>.05) and between baseline and distraction ICP (F = 0.279; P>.05) at any load. In the single animal that underwent additional distractive forces, movement across the coronal suture was not seen until the 500-g force, which produced 0.30 mm of separation but no corresponding ICP changes.

Conclusion: Low loads of force, similar to those used clinically when performing a Craniosacral frontal lift technique, resulted in no significant changes in coronal suture movement or ICP in rabbits. These results suggest that a different biological basis for craniosacral therapy should be explored. J Orthop Sports Phys Ther. 2006; 36(11):845-853. doi:10.2519/jospt.2006.2278

Key Words: cranial bone movement, cranial sutures, manual therapy


The abstract provided above is from a paper recently published in The Journal Of Orthopaedic and Sports Physical Therapy.(3) An accompanying editorial(5) by orthopaedic PT researchers suggested that:
"We need to abandon CST as a viable rehabilitative theory (i.e., that cranial sutures move) and instead focus on whether any of these procedures as manual techniques can be proven effective for specific musculoskeletal conditions."
(Italics mine.)

While I agree completely with the need to scientifically study and reject the implausible hypotheses associated with the equally implausible underlying theory of craniosacral therapy (even if it requires the sacrifice of rabbits to do so) I do not entirely support the editorial statement quoted above. I think it doesn't quite hit the mark - it completely leaves out the phenomenon of persistent pain, a condition in its own right, which can occur completely divorced from any "specific musculoskeletal condition." In fact, it usually does. Why? Because persistent pain problems are nervous system based, perhaps connected to movement dysfunction but not “musculoskeletal” (orthopaedic) “conditions”. I do NOT agree therefore, that everything in PT or in manual therapy provided by PT must be elucidated or defined according to "musculoskeletal" dictates, by being “proven effective for specific musculoskeletal conditions.” I think the orthopaedic PTs have made a category error in their editorial, understandable given their focus on mesodermal derivatives (i.e., bones, joints, muscles), and I am writing this to challenge their assumptions, as well as to support the Downey report in its challenge of craniosacral theory as being an invalid construct.(3)

Regarding theory, there are perfectly acceptable neurological mechanisms to account for the rumored efficacy and clinical usefulness (pain relief, increased sense of well-being) of the procedures associated with craniosacral therapy (CST). Perhaps it's time we rationally deconstruct this infamous form of manual treatment and take a slow look at what might be happening in the nervous system that is on the receiving end of the application.

These are some thoughts I have on the topic (I’m sure others can add more):

1. According to Neuromatrix theory(6) (Ron Melzack), the "body-self neuromatrix" "comprises sensory, affective, and cognitive neuromodules." Continuously through time, inputs into the system will be processed by this neuromatrix, and output such as stress regulation, action programs (including reflexive motor activity), and pain perception, will ensue. There are three "motor" systems involved: voluntary, autonomic, and neuroendocrine (Brain Architecture(7), Larry Swanson) working independently/interdependently/continuously (with one exception: the voluntary system during sleep). The application of a set of therapeutic hands on the head will be interpreted by the neuromatrix as helpful or harmful, depending on multiple historical factors such as the patient's beliefs and experience. At the very least, because manual treatment to the head (or anywhere else) is primarily a sensory-discriminative input into a nervous system, frequently a sensitized one, it is imperative that it be non-nociceptive, devoid of threat - five grams is indeed sufficient to facilitate change if we base our intervention on neuromatrix theory. In short, the nervous system is more of a verb than a noun.

2. Contact on the back of the head stimulates mechanoreceptors – mechanically stimulated sensory information travels in through cutaneous nerves (the occipital nerves, cutaneous branches from upper cervical spinal nerve roots) to dorsal root ganglia. From there, benign exteroceptive (arising from outside the body) input is handled by the CNS, both at a spinal cord level and at a sensory cortex level(7). Part of this input is processed non-consciously, resulting in motor output that is reflexive (e.g., increase in blood flow to scalp and associated cutaneous neural tunnels, outward to the rest of the body), and the rest of the input is evaluated by the sensory cortex/conscious awareness of the patient, where it filters through all parts of the brain, reaching into the cognitive-evaluative and motivational-affective aspects of an awake individual's central nervous system, as well as to all the motor output parts yet again.

The trigeminal ganglion receives and processes any exteroceptive input from the skin on the front of the head/face. The trigeminal ganglion is like a dorsal root ganglion, except that it is also a central nervous system structure, and is intimately connected to other CNS processors and effectors.

Exteroceptive sensation will quickly get the attention of the nervous system, and be scrutinized by it, as will any novel stimuli(2), for any potential threat before it will be accepted as neutral, comforting, pleasure inducing, educative in a kinesthetic sense, as naturally as interoceptive (arising from within the body) sensation.

3. Any sort of therapeutically contexted physical contact can catalyze change in a nervous system. The practitioner's job is to have an idea what a good result might consist of, seek out and enhance and teach patients the characteristics of "correction" - i.e., warmth, softening, a sense of surprise and effortless movement(4) (Barrett Dorko) during and directly after a session. The patient's job is to be willing to seek out and accommodate lasting change. An ethical practitioner must be willing to remain a mere catalyst, encouraging development of self-efficacy, not "maintenance" dependence.

4. Patrick Wall said, "A placebo is not something that is administered TO a patient, it is something that is elicited FROM a patient."(8)

5. The therapeutic container or relationship is the responsibility of the practitioner. It will serve to establish a physical and psychological safe "crucible" in which a lasting "reaction" can occur, after which time it should dissolve, never to be perpetuated as a “maintenance” scheme fostering dependency. Part of the attached responsibility of a practitioner is to strive for truth and clarity, be accurate as possible in setting out facts of treatment and pain education. Perpetuating implausible hypotheses/ memeplexes(1) when science suggests otherwise is not ethical in a therapeutic relationship and not acceptable from a professional standpoint. Using metaphor to illustrate an idea or a kinesthetic perception is perfectly acceptable - the practitioner must self-educate to know the difference, draw a line, and then toe it.

6. Neuroscience and pain science can be drawn on to defend the use of any procedure used in physio/physical/manual therapy. There is no need to resort to anti-scientific or pseudo-scientific constructs to explain soft tissue treatment techniques to patients (or hard-tissue treatment techniques either); eventually the faulty memes that accompany useful procedures must all be eliminated, discarded, replaced by better ones.

We can support professional and science-based use of gentle forms of manual therapy by doing valid and reproducible outcome studies; we will thereby continually improve this profession, help one another treat our patients meaningfully and respectfully, teach them to battle pain through understanding it, and enjoy increased amounts of our already widespread credibility.

7. I leave you with this thought on the subject of complexity:
"Was it really true, that all this business of chaos and complexity is based on two simple ideas - the sensitivity of a system to its starting conditions, and feedback? Yes, he replied, that's all there is to it."

-John Gribbin, author of Deep Simplicity, speaking of his conversation with James Lovelock.


1. Blackmore, S.; The Meme Machine; Oxford University Press 1999

2. Butler, David; Moseley, Lorimer; Explain Pain: NOIGROUP publications

3. Downey, P.A.; Barbano, T.; Kapur-Wadhwa, R.; Sciote, J.J.; Siegel, M.I.; Mooney, M.P.; Craniosacral Therapy: The Effects of Cranial Manipulation on Intracranial Pressure and Cranial Bone Movement; JOSPT 2006; 36(11):834-836. doi: 10.2519/jospt.2006.2278

4. Dorko, B.; Characteristics of Correction

5. Flynn, T.W.; Cleland, J.A.; Schaible, P; Craniosacral Therapy and Professional Responsibility; JOSPT 2006; 36(11):834-836. doi: 10.2519/jospt.2006.0112

6. 2003Melzack, Ron; Pain and the neuromatrix in the brain: J Dent Educ. 65(12): 1378-1382 2001 © 2001 American Dental Education Association

7. Swanson, Larry; Brain Architecture: Understanding the Basic Plan: Oxford University Press 2003

8. Wall, P.; Pain: The Science of Suffering; Columbia University Press 2000