Cerebrospinal fluid (CSF) is the great liquid cushion that surrounds the brain and spinal cord, protecting it both structurally and immunologically. It’s a feat of nature that “maintains the electrolytic environment of the central nervous system (CNS), influences systemic acid-base balance, serves as a medium for the supply of nutrients to neuronal and glial cells, functions as a lymphatic system for the CNS by removing the waste products of cellular metabolism, and transports hormones, neurotransmitters, releasing factors, and other neuropeptides throughout the CNS .”
It’s a big job for the 150ml of CSF that flows around the CNS at any given time (approx.).
But that’s hardly news to chiropractors. What may be news is the potential link between posture, CSF, and neurodegenerative diseases. It all has to do with pressure gradients that may build up as a result of subluxations and/or poor posture, thus slowing the removal of brain waste material.
As practitioners of the Sacro-Occipital Technique (SOT) will happily tell us, neuromechanical dysfunction or vertebral subluxations can impede the flow of CSF.
CSF moves out of the brain and spinal cord via the dural venous sinuses, taking central nervous system waste with it. It’s a constant process that is vital for health. But when we are subluxated, and experience postural changes, CSF flow is implicated.
With SOT, chiropractors are on the lookout for anything that impedes this CSF flow. If the sacroiliac joints become fixed, this may “cause compensatory changes in the hips, sacrum and remaining spine .” i.e. Posture can change. But when we look from the sacrum to the occiput, we can begin to see how postural change, rib excursion and subluxations in the upper spinal region are potentially a big deal for CSF flow.
Key considerations in SOT include dural attachments through the Occiput and Sacrum. A major area of focus is C1-C2 and the cervico-thoracic junction – an area also heavily impacted by forward head posture, as well as being a key focus of upper cervical care [2, 3, 4]. When it comes to CSF flow, there is evidence that the body works with respiration: i.e. the cranial nerves will flex and pump the CSF fluid as the person breathes in and out . When there is wind-up in the cervical and upper thoracic region, as there is in forward head posture and thoracic kyphosis, it can impact respiration via lung function, rib excursion and tidal volumes . The temporal-mandibular joints may also start to wind up, creating jaw tension and impacting the cranial nerve system and by virtue of the latter, potentially impacting CSF flow .
The vital system that clears waste from the CNS is therefore impacted, and science is beginning to offer up insights into how much this matters for ongoing brain health.
If CSF flow is essential, then it’s absence or impedance is detrimental.
Whedon and Glassey, in their paper on the clinical significance of CSF stasis, wrote that, “There is evidence to suggest that CSF stasis may occur commonly in the absence of pathology or symptomatology, and may have adverse systemic health effects .” This CSF stasis (or slowed/impeded CSF flow) could, according to Whedon and Glassey, be associated with “adverse mechanical cord tension, vertebral subluxation syndrome, reduced cranial rhythmic impulse and restricted respiratory function.” They suggested further investigation into the cause and nature of CSF stasis, but there is early research to suggest that chiropractic has a role in removing impediments to CSF flow, thus supporting a healthy system.
In order to understand the link between posture and neurodegenerative disease, one must first look to recent developments in brain science. For years, we held the belief that the brain was a privileged organ, with an intact blood/brain barrier, and that immune responses involving the brain were highly unusual and problematic.
All that changed when Dr Antoine Louveau observed a lymphatic vessel in the brain that had eluded researchers for years. This game-changing discovery meant that, all of a sudden, it was clear that the brain did not lack a connection to the lymphatic system as previously thought. Lymphatic channels did indeed exist in the brain, and this had big implications.
Louveau remarked, in an interview, that his team’s discovery meant that the brain could be seen by the immune system, and that this was highly significant [6, 7]:
“We think that this discovery is highly significant because… the brain is a privileged organ. Usually when you have an immune response in the brain it’s considered to be a bad thing. What we know [sic] from several years now, is that there are immune cells in your brain under normal conditions and that is actually good for your brain but the big question we still had is ‘how do those cells get in and get out of the brain?’ The system we discovered is actually way of how those cells are able to get out of the brain and do what they are supposed to do.
You have a lot of neurological diseases that have this [sic] immune component. We think that our discovery might lead to new therapeutic ideas on how to address those diseases in the future.”
Among those diseases were things like Alzheimer’s Disease and Multiple Sclerosis. By way of example, Louveau went on to explain:
“Alzheimer’s Disease might involve that structure [the lymphatic vessel in the brain] because, as we know, it’s an accumulation of proteins in the brain that are supposed to removed from the brain. We think the [lymphatic] vessel that we newly discovered might be clogged … and that may start the disease,” he remarked, speculating that faults in lymphatic drainage may be the starting point for neurodegenerative diseases, while also careful to reinforce the need for further study.
Logically, it’s clear that the glymphatic system (a newly-coined term for the functional waste clearance mechanism for the CNS) has a significant role to play, because something has to get rid of the brain’s waste products. What has this to do with CSF flow and posture? Again we look to the basic science that surrounds this new discovery.
There is already research noting that glymphatic drainage may be impaired in patients with Multiple Sclerosis, and that CSF biomarkers are useful in the diagnosis of neurodegenerative diseases like Alzheimer’s and Parkinson’s Diseases as well as Huntington’s, Motor Neurone (ALS) and Machado Joseph’s diseases [8, 9, 10]. But a hypothesis paper by chiropractor and ex-Harvard scholar Dr Amy Haas begun to shed some light on what this might mean for chiropractic .
Haas’s hypothesis showed, by exploration of basic science, how pressure gradients that develop inside a subluxated spine could contribute to a compromised CSF flow, and that adjusting the spine could relieve these pressure gradients and support optimal CSF flow – thus impacting the clearance of brain waste from the central nervous system.
In an earlier interview with Spinal Research, Dr Haas explained :
“CNS Lymphatic drainage is a bit of an interesting subset because it drains into the deep cervical lymph nodes. Essentially, [if there are lymphatic drainage issues] it’s a plumbing problem. Drainage from the deep cervical lymph nodes is dependent on a pressure gradient,” explains Haas. “While extra-cranial lymphatic drainage is assisted via muscle contraction, the cranium is a closed compartment; you don’t have any muscle contraction. Therefore drainage has to depend only on a pressure gradient. Anything that backs up that pressure gradient will slow the transfer of fluid.”
For Haas, it was easy to see how a subluxation could potentially impact the pressure gradient and slow the transfer of waste from the brain (this links to an emerging concept in science that neurodegenerative disease may involve a mismatch between the speed at which waste is produced in the brain, and the speed at which it is removed from the brain by the glymphatic system). By way of example, she explained:
“Let’s say for example you have an atlas subluxation; you rotate the atlas and you can put pressure on the internal jugular vein. That has been shown by research and I cited in the paper . An atlas subluxation may impinge drainage through the internal jugular vein. That may in turn increase the CSF pressure because it can no longer drain quickly and freely via the cervical lymph nodes and the internal jugular vein. When the CSF pressure is increased just a little bit, that will affect the lymphatic drainage through the channels adjacent to and lining the dural sinuses because that also has to be pressure dependent. When the dural sinuses are become compressed by fluid pressure, you can no longer see the channel [the lymphatic vessel in the brain]. It is not a solid channel. That is a channel that is very changeable. So that brings up the possibility (at this point an unproven hypothesis) that if an atlas subluxation were to slow the drainage of the venous blood out of the cranial cavity, then you develop a pressure gradient.
When you work backwards in that plumbing problem, the pressure gradient could slow the process of lymphatic drainage just by virtue of pressure. And furthermore lymphatic drainage is postulated to be the mechanism by which the glymphatic system in the deep brain tissues gets rid of cellular debris from deep brain tissues. Louveau postulates that interference of proper drainage through the CNS lymphatic system could be the root cause of many neurodegenerative disorders [6, 7]. That is exactly what caught my eye. Louveau is a PhD scientist in a completely non-chiropractic realm saying if you don’t properly drain waste out of the brain you could end up with Parkinson’s.”
Like the Louveau discovery, Haas’s hypothesis needs further research to verify it and to extrapolate the implications for chiropractic care. Still, it’s a fascinating insight into how the subluxation could impact CSF flow and then degenerative diseases.
Is posture linked to subluxation? Chiropractic veterans and novices alike would agree with a resounding yes. But even outside of the SOT lens, it is obvious that postural changes can create subluxation. Perhaps this process is best illustrated in the words of by chiropractor, Dr Chris Kent :
“Postural changes are mediated by receptors that monitor the dynamics of the internal and external environment, and the relationship of the individual with the environment. The receptor systems that may contribute to postural alteration include:
If vertebral subluxation results in aberrant afferent input to the CNS, inappropriate motor responses may cause postural aberrations.”
It’s that clear.
What is becoming increasingly clear is that the chiropractors role in the restoration of posture and the removal of subluxations may have implications for neurodegenerative diseases. We need more research, but the basic science is beginning to line the ducks up for us.
A subluxated spine may impact the flow of CSF in and around the nervous system. As the brain uses CSF to get waste from the lymphatic vessels in the brain to the body’s venous circulation, thus preventing a build up of brain waste, proteins or plaque, the removal of subluxations could have significant impacts.
Only time and research will show us for sure. In the mean time, who’d want to risk neurodegeneration when postural correction and chiropractic care offer such potential benefits?