Editor’s Memo: Spinal Fluid Flow and Pain Management – practicalpainmanagement.com – Editor’s Memo June 2017 By Forest Tennant, MD, DrPH
Spinal fluid flow (SFF) [also called cerebrospinal fluid, CSF] has been a silent subject in pain management.
This has to change.
For a while, pain practitioners have unknowingly been utilizing a variety of measures that likely enhance SFF.
Progressive research that involves SFF has shown how it occurs, how it may promote pain, and how it may impede treatment efforts.
Specifically, our new understanding is that
- neuroprotection, and
which are critical elements of pain management, are all dependent on some degree of SFF.
The basic physiologic functions of cerebrospinal fluid (CSF) are now known.
The central nervous system (brain and spinal cord) contains about 125 to 150 mL of CSF.
It is produced from serum in the choroid plexus in the brain’s ventral system.
Incredibly, the entire amount of CSF turns over about 4 times a day (total production, 400-500 mL/d).
Its functions are multiple:
- Transport of nutrients
- Barrier to cushion trauma to the brain
- Lubricant to prevent friction between nerve roots and the canal lining
- Disposal of waste products (harmful metabolites, drugs, and other substances)
CSF exits the brain and spinal canal through cranial lymph and glymphatic channels to enter the general circulation.
Sleep promotes clearance of metabolites and waste, such as amyloid and neuroinflammatory by-products.
Nutrients that are transported from serum into the CSF include vitamins B1, B12, and C; folate; beta-2 microglobulin; arginine vasopressin; and nitrous oxide.
Interestingly, the pump, or mechanism, that drives CSF downward from the site of production in the brain to the sacral area and then back up to the brain sites for reabsorption in the general circulation is unclear.
The best theory at this time is that arterial pressure in arteries around the choroid plexus propels fluid movement.
Breathing may also promote fluid movement.
Role of Spinal Fluid Flow in Pain Management
Regardless, SFF does not have an active, visible pump like the heart to drive fluid flow. The relevance of SFF to practical pain management is clear.
Good SFF is:
- Critical to providing nutrients to the spinal cord canal and cauda equina nerve roots
- An essential component in preventing friction between nerve roots
- Needed to carry away waste products from neuro-inflammation
- Vital for bringing therapeutic drugs to target areas such as the cauda equina
The answers to the major questions for pain management are incompletely known: How do we diagnose SFF impairment, and what do we do about it?
Symptomatically, pain patients with SFF impairment may complain of weakness, headache, blurred vision, tinnitus, or increased pain if they stand or sit too long.
Some will have to lie or sit down after standing for only a few minutes.
Contrast magnetic resonance imaging (MRI) may now show, for example, spinal fluid on only one side of the cord in the cervical or lumbar spine areas. The thecal sac may sometimes look distended in the lumbar area if there is obstruction in the sacral area.
Some studies of pressure gradients in the spinal cord suggest that anything that protrudes into or narrows the spinal canal may cause pressure gradients across the canal and impede SFF
It is likely that common spinal conditions, such as protruding discs, stenosis, kyphoscoliosis, and arachnoiditis, may all impede SFF.
The instability of our spinal joints as a consequence of having EDS undoubtedly leads to an increased likelihood of deformities in the spinal canal which would then lead to impaired CSF circulation.
One consequence can be getting those horrible “spinal headaches” as a result of too much or too little fluid pressure around the brain.
impaired SFF may
- leave initiating inflammatory waste in the CSF,
- deprive the spinal cord and nerve roots of nutrition, and
- prevent therapeutic agents from reaching target areas.
Age-Old Treatments May Help
It may also well be that many of the age-old techniques used to treat basic pain exact their effect by increasing SFF.
These techniques include
- massage and manipulation of the spine.
- heat, and
- yoga may all help SFF.
The most notable recollection that comes to my mind is that the renowned pain physician, Janet Travell, MD, became John F. Kennedy’s pain physician in 1955 after he had developed multiple spine problems and had failed multiple spine surgeries.
Her first treatment was not opioids but was a rocking chair. (also see The Medical Ordeals and Chronic Pain of JFK)
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Johanson CE, Duncan JA, Klinge PM, Brinker T, Stopa EG, Silverberg GD. Multiplicity of cerebrospinal fluid functions: new challenges in health and disease. Cerebrospinal Fluid Res. 2008;5:10.
Johanson C, Duncan J, Baird A, Stopa E, McMillan P. Choroid plexus: a key player in neuroprotection and neuroregeneration. Int J Neuroprot Neuroregener. 2005;1:77-85.
Xie L, Kang H, Xu Q, et al. Sleep drives metabolite clearance from the adult brain. Science. 2013;342(6156:373-377.
Researching my frequent disabling headaches, I learned these can be caused by disruptions of our cerebrospinal fluid pressure.
This is common with EDS because the instability of the cervical spine from EDS can lead to problems with cerebrospinal fluid dynamics: