Advanced Osteopathic and Chiropractic Techniques for Manual Therapists. Giles Gyer
a person depends on the smooth functioning of all structures in the body, including bones, muscles, tendons, ligaments and organs. By manipulating a patient’s muscles or joints, therapists tend to aid the body’s self-healing ability, correcting the structural anomalies (Di Fabio 1992; Vickers and Zollman 1999).
Several studies have confirmed that manipulation of the spine can influence some organ functions (Bakris et al. 2007; Budgell 1999; Hawk et al. 2007). However, it is not yet known how spinal manipulation affects visceral function, and whether these effects are clinically relevant in the treatment of visceral diseases. Most of the early theories concerning the effect of manipulation on the visceral system are largely focused on vitalism. Recent theories propose that all organs and structures of the body slide and glide with an interconnected synchronicity, as the whole body is enveloped by an uninterrupted network of connective tissue known as fascia (Hall 2012). Accordingly, the visceral system depends on this synchronicity to function smoothly. In healthy individuals, this harmony remains stable regardless of our body’s endless variations in motion. But when the synchronicity in movement is affected due to formation of adhesions or abnormal muscle tone, it results in an erratic tension between organs, and ultimately limits the body’s normal range of motion. This, in turn, leads to disease and dysfunction of various systems of the body.
Therapists of spinal manipulation claim to correct this disharmony by first locating the source of the problem through palpation, and then realigning changes in the biomechanical dynamics (e.g., position and movement faults) by manipulation. However, many critics of spinal manipulation have rejected such a claim, since there is no direct neural connection between the spine and visceral system. Some have even remarked that the claim is completely unrealistic, arguing that visceral tissues do not depend on spinal nerve root signals to run themselves. In addition, organs could function smoothly on their own, even if a spinal nerve root is cut. Hence, the critics mainly argue that there is no justifiable reason that spinal manipulation can address visceral disorders. In support of this argument, they also say that spinal manipulation has a valid concept in treating musculoskeletal disorders, as musculoskeletal structures rely on the nerves that pass between vertebrae (Ingraham 2017).
No neurological connection between the spine and organs: A brief rebuttal
It is undeniable what the critics of spinal manipulation argue concerning its neurophysiological limitations in addressing visceral disorders. But we strongly disagree with the argument that manipulation has no reasonable theoretical basis to modulate visceral function. Although the corpus of literature is small, there is some evidence that spinal manipulation is beneficial for certain visceral disorders (Bakris et al. 2007; Budgell 1999). We agree that a comprehensive neurobiological rationale is still missing to justify our claim. However, this is not due to there being no neurological connection between the visceral system and the spine, but because of the limited interests of case studies and controlled trials in exploring neural mechanisms (Bolton and Budgell 2012). So far, only a few basic physiological studies in humans have been done to determine the mechanisms underlying the visceral responses of spinal manipulation. Some authors have already attributed these responses to somato-autonomic reflexes (Jowsey and Perry 2010; Moulson and Watson 2006; Perry et al. 2011). While this is not unreasonable, others have suggested alternative mechanisms such as an involvement of somato-humoral pathways (Bolton and Budgell 2012).
The autonomic nervous system (ANS) controls the involuntary bodily responses. It regulates and supplies various organs of the viscera such as the heart, kidneys, liver, lungs and digestive glands. The ANS also has potential interaction with the nociceptive (pain) system on multiple levels, which include the brain stem, fore brain, periphery and dorsal horn (Benarroch 2006). Therefore, any intervention that influences the functions of the ANS has significant clinical relevance. The effects of spinal manipulation on the ANS are well established in the literature. This has been demonstrated using various outcome measures such as heart rate variability, pupillary reflex and skin blood flow indexes (Bolton and Budgell 2012; Sampath et al. 2015). In addition, several studies done to investigate the neuroendocrine responses have reported a manipulation-induced increase in serum cortisol levels (Padayachy et al. 2010; Plaza-Manzano et al. 2014). Hence, in the theorised mechanisms of spinal manipulation, the peripheral sympathetic nervous system (PSNS) has been given a prominent role in the modulation of pain and inflammation.
Furthermore, after reviewing a range of mechanistic studies, Sampath et al. (2015) hypothesised that spinal manipulation might co-activate both the ANS and endocrine system. Since these two systems have been reported to work together, the authors suggested that post-manipulation changes in the ANS might be accompanied by changes in the function of the hypothalamic–pituitary–adrenal (HPA) axis. They also proposed a possible neural framework in support of their hypothesis. Taken together, it can be said that the autonomically mediated responses and the somato-humoural pathways are justifiable areas of research to demonstrate the visceral effects of spinal manipulation. In addition, it is totally baseless to say that mechanical stimulation of the spine has no neurobiological basis to influence the visceral organs. Even if there is no direct neural connection between the body’s organs and the spine, spinal manipulation could indirectly result in measurable changes in the visceral system mediated by the ANS.
Misunderstanding, or intentional misinterpretation?
Some critics are so critical about spinal manipulation, as if nothing ‘good’ can be expected from it! They find unthinkable problems in the basic philosophy and principles of manipulation, and consider every theoretical explanation to be flawed, no matter the evidence against them. One common argument of these critics against the use of spinal manipulation in visceral disorders is that organs are not affected even if a spinal nerve root is completely cut, so there is no valid point in using the therapy. Is this really so?
It is true that the complete loss of a spinal nerve root will certainly paralyse something in the musculoskeletal structure, but not a visceral organ. However, this does not mean organs are not affected at all, even if a serious spinal injury occurs. After a major spinal nerve injury, organs will continue to run smoothly for a short duration, but the long-term fate of them is scary. There will, in fact, be autonomic dysregulation over time, which will gradually lead to organ dysfunction and make matters worse for overall systemic health (Sezer, Akkuş and Uğurlu 2015; Stein et al. 2010). This actually proves the oldest philosophy of spinal manipulation, that all organs and structures in the body work interdependently, and that spinal health is critical for their smooth functioning. Moreover, because spinal manipulation has been reported to influence various functions of the ANS, the argument that manipulation cannot affect visceral function becomes invalid, although these effects are indirect.
On the other hand, we believe the critics have also misunderstood the very concept on which therapists of spinal manipulation treat visceral disorders. The basic theory of visceral manipulation, that all the body’s organs and structures move with an interconnected synchronicity, is actually based on fascia, not on nerve supply from the spine to the organs. A fascia is an interconnected network of fibrous collagenous tissues that has the ability to adjust its elasticity and consistency under tension (Findley et al. 2012). It supports the body in a number of ways, by:
• providing ongoing physiological support for the body’s metabolically active systems composed of specialised cells and tissues
• connecting, communicating and coordinating all parts of the body in its entirety
• contributing to haemodynamic and biochemical processes
• assisting in response to mechanical stress
• maintaining posture and locomotion
• facilitating movements.
The effects of spinal manipulation on fascia have been confirmed in the current literature. Manipulation has been reported to breach fascial crosslinks, ease fascial tightness and normalise fascial motion (Harper, Steinbeck and Aron 2016; Oulianova 2011; Simmonds, Miller and Gemmell 2012). Therefore, we conclude that it is unreasonable to find problems with our claim that manipulation corrects disharmony in visceral movement.
In conclusion, we suggest that before labelling