Why a little Embryology can save you from a back surgery that will not help you.
I understand that no one enjoys embryology, but just a tad bit is useful to better understand your pain and treatment options.
I’ll try and make it understandable and while some of this is for my colleagues and I’m not even sure if I understand it all hopefully you’ll understand at the end that chiropractic can be your best friend.
What I do know is that what I learned from this recent study was that I already knew this stuff from 40 years of practice. This stuff means that most patients do not require surgery and that a fast stretch cavitation of a zygapophyseal joint can work miracles. That is a fancy way of saying a chiropractic adjustment. For the laymen, you can stop reading now but at the end of each paragraph I try and make it more friendly and useful for you.
We’ve all heard the term sciatica and seem to know that it is pain from your spinal nerves in your low back that go down your leg. Not so fast, there are lots of neurological conditions that can cause pain down your leg or legs and they are not all sciatica. Sciatica is a subset of radiculopathy. Radicular is Latin for root and we have nerve roots that begin after nerve branches leave our spinal cords to form these roots. We need to consider the structures involved in this neurophysiology. These structures have different embryological origins or derivations and understanding this provides doctors with more efficient ways to manage and treat your pain.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
For academic reasons we’re going to consider any pain, as nociceptive or neuropathic, no matter what the anatomical region or source. So now whether you have a headache, backache, or shoulder pain, etc. it is nociceptive(pain producing) or neuropathic. So what that means is that either the pain being generated is either neural or not neural. If the damaged or diseased structure is neural, the pain is neuropathic. If the structure is not neural, the pain is nociceptive.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
Once an egg cell is fertilized it is going to make 3 basic layers of different types of cells. The one we’re interested in is the ectoderm which eventually becomes our skin and our nervous system. Even the surface ectoderm, the skin is not related to are not related to spine and radicular pain.
The spine that protects 20% of the central nervous system is derived from the mesoderm. These spinal structures from the mesoderm are capable of producing pain signals. Examples of these structures are ligaments, discs, spinal joints, sacroiliac joint, dura mater and muscles.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
Many different cells within the affected structures release a variety of inflammatory mediators that can lead to the depolarization of the receptive terminals of the neurons that innervate the injured/diseased structures. These receptive structures, called nociceptors, are not injured; they are simply responding normally to damaging or potentially damaging stimuli. Nociception is also known as pain and these receptors are nerves that transmit pain. They are mostly on C nerve fibers, very small and very slow traveling nerves. Slow because they are small. You can drive faster on a freeway than a small alleyway.
So pain signals are transmitted up to the thalamic portion of our brains and if that signal is interrupted by any number of means, you will not feel the pain. Novocaine is an example of interrupting the nerve signal. Rubbing some analgesic cream onto your skin stimulates your B nerves which are bigger than the pain C nerves and they get to your thalamus first and take the pains parking spot and you feel more comfortable. Type A nerves are the biggest, strongest, fastest nerves in your body and that is what a chiropractor is stimulating when he cracks your back.
Most spinal pain is considered nociceptive and not neuropathic. Maybe 1% of patients have a disk injury that is not contained and presses upon the nerve root creating irritation that needs to be resolved with surgery. So that is really good news for you if you are suffering with a crippling back ache. The probability is low that you will require surgery.
Is radicular pain nociceptive or neuropathic? The nerve root, is a purely neuroectoderm-derived structure; in other words, it is purely neural. It is not ensheathed in connective tissues like peripheral nerves. Dorsal and ventral roots float within cerebral spinal fluid, which separates them from the dura mater. In contrast, a peripheral nerve is a mixed structure, consisting of neuroectoderm-derived axons that are surrounded by mesoderm-derived epineurium and perineurium, which make up the peripheral nerve sheath. A peripheral nerve thus consists of a connective tissue tube that surrounds bundles of axons. What all that means is it is rather difficult for the clinician to determine the nature of your pain. One problem can mimic another. Your pain may seem like it is definitely neurogenic pain, but it can very well respond to chiropractic treatment since it more likely than not is not being caused by nerve root compression.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
The dura is a somatic structure; it is a mesoderm-derived connective tissue and, as mentioned above, it is anatomically distinct from the nerve root that it surrounds. However, what can be confusing is that at the intervertebral foramina, the dura becomes continuous with the spinal and peripheral nerve epineurium, which is considered to be part of the peripheral nerve.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
We know that both the dura and epineurium are innervated by nociceptors, such that inflammation of the dura and epineurium can lead to nociceptive pain. I think in older text books we referred to this as sclerotogenous pain. If you are a patient you really don’t care what we call it, you are just hoping that we can resolve it and chiropractic is usually the best way to treat these non surgical cases. As the dura and epineurium are mesoderm-derived somatic structures, the painful symptoms are likely to be similar to those generated by other somatic structures of the spine, such as muscles, disc, ligaments, and joints.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
Nociceptive pain is typically described as a deep, non-cutaneous pain that is dull and achy, but can also have sharp, throbbing, gnawing, and burning qualities. Normal movements and physical examination procedures can reproduce the painful symptoms; however, patients with nociceptive pain do not suffer from dynamic tactile allodynia, which is reserved for patients with neuropathic pain.
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For “radicular pain” to be neuropathic, dynamic tactile allodynia must be present, which is experienced as excruciating pain every time clothes touch the skin. It is a crushing pain that is distinct from nociceptive pain. Patients with true neuropathic pain will also suffer from brutal spontaneous pain than can feel like boiling water and/or bursts of painful “pins and needles.
Commonly used nerve tension tests, such as the straight leg raise, almost never elicit neuropathic pain descriptions described above, which suggests that the nerve root and spinal nerve axons are not injured in the vast majority of patients with radicular pain. However, clinicians are aware that radicular pain is different from nociceptive pain, such that it can be spontaneously produced while lying supine and it radiates sharply upon nerve root tension tests.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
Clinicians know that most disc herniation patients, especially non-surgical candidates, do not suffer from dynamic tactile allodynia, and do not perceive skin pain even during a straight leg raise test. These observations form the root of the confusion associated with radicular pain, suggesting a nociceptive/neuropathic variant. However, relatively recent research offers a solution to this confusion.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
Inflammatory substances applied to the nerve’s connective tissue sheaths leads to focal inflammation that affects the sheathed axons within, but does not injure them.
There are two known effects of inflammation on nociceptor axons. The most clinically important effect is that some nociceptor axons become mechanically sensitive, whereas they are normally mechanically insensitive. This phenomenon only occurs in slowly conducing axons, and primarily in those innervating non-cutaneous structures. This is consistent with pain elicited in the leg during a straight leg raise, which applies mechanical force to the inflamed nerve, and which leads to the perception of deep pain.
The other effect is that the inflammation causes spontaneous discharge of normally silent nociceptors. This is expected to lead to pain at rest. It is not clear at this point if this effect is limited to deep neurons or not, but does occur with some cutaneous nociceptors.
FOR THE PATIENT: The above meant that this is going to help the chiropractor help you to avoid surgery.
