First a huge and important disclaimer. I am not in any way medically qualified, and do not pretend to be. Everything I say is from a viewpoint of a person with 10 years-worth of sciatica suffering. I have tried to write accurately but I cannot guarantee I have got everything right. I’m very happy for physiotherapists, or other clinicians, to put me right on anything!
What is radicular pain?
Radicular pain is pain arising from the irritation of a nerve root. This may be a sciatic nerve root, or could be a nerve root in another part of the body.
Many people think of radicular pain as ‘radiating’ from the nerve root down the associated nerve, but in my experience, and that of others, this is not a good description of radicular pain. For example, my sciatic pain is caused by the irritation of one of my sciatic nerve roots (S1), but I often experience pain in only the lower leg, or only the buttocks, or only the upper thigh, or only the foot, or sometimes a combination of these. I do occasionally experience pain that literally radiates straight down my sciatic nerve, but that may not be the norm.
Radicular pain can take multiple forms. Sometimes it can be felt of as sharp shooting pains and sometimes as a burning sensation. It can have an ‘electric’ type quality, and can sometimes feel like an electric shock.
Radicular pain can be thought of as a subset of neuropathic pain. Neuropathic pain refers to pain related to any nerve in the body (including nerve roots), whilst radicular pain refers to pain specifically related to a nerve root. Sciatic pain is a subset of radicular pain (and therefore neuropathic pain) as it refers to pain related to one, or more, of the sciatic nerve roots.
What is radiculopathy?
When a nerve root is compressed or damaged then you may experience sensation changes, such as numbness, weakened reflexes and motor loss. This is called radiculopathy. Radiculopathy occurs because some of the nerve signals are blocked from travelling through the nerve.
The numbness is distributed roughly along the path of the nerve (along the relevant dermatome) and any motor weakness will relate to the group of muscles that the relevant nerve serves.
Although radiculopathy and radicular pain commonly occur together, radiculopathy can occur in the absence of pain, and radicular pain can occur in the absence of radiculopathy.
It should be noted that some people refer to radiculopathy as including radicular pain. I don’t think this is strictly correct, but is quite common.
The nerve root affected in radiculopathy may be the sciatic nerve root, but like radicular pain, it could be a different nerve root in the body.
Radiculopathy can be thought of as a subset of neuropathy. Neuropathy refers to the symptoms occuring because some of the nerve signals are blocked, but this could be for any nerve in the body (including any nerve root). Radiculopathy specifically refers to a nerve root.
In the same way that radiculopathy is commonly used to encompass both the pain and the changes in sensor/motor control arising from a nerve root, neuropathy is often used to encompass similar symptoms, but for any nerve in the body (including any nerve root).
What is radicular syndrome?
When you have radicular pain combined with radiculopathy (from the same nerve root) then you might be diagnosed with radicular syndrome, however I don’t think this terminology is commonly used in practice.
Some people get radicular syndrome in their arms, arising from irritation of a nerve root in their neck, others may experience symptoms in their legs, arising from irritation of a nerve root in their back.
Radicular syndrome can be thought of as a subset of neuropathy (neuropathy refers to any nerve in the body, including nerve roots, whilst radicular syndrome is focused on nerve roots).
What is sciatica?
I have discovered whilst trying to clean up this jigsaw piece that there is no commonly agreed ‘definition’ or shared understanding of the term ‘sciatica’. Different clinicians have different views, and the information available to the public on the Internet, or within books, reflects that lack of consensus.
There also seems to be debate about whether sciatica is a symptom of another condition or a diagnosis in it’s own right.
I have decided to look at ‘What is sciatica’ in two different ways. First of all I have looked at what a ‘strict’ definition of sciatica might be, and then secondly I have taken a pragmatic view of how I think the rheumatologist who gave me my diagnosis of sciatica considered my condition to be, and how I think my condition pragmatically fits into an overall ‘concept’ of ‘sciatica’.
Strict definition of sciatica
My understanding is that in strict and simple terms, sciatica is the name given to pain caused by irritation of one or more of the sciatic nerve roots in the lower back. Pain might be felt anywhere along and around the path of the sciatic nerve, even though the actual irritation is at the site of one of the sciatic nerve roots in the lower back. Sciatica may be associated with neurological dysfunction, such as weakness and numbness, but strictly speaking the term sciatica only describes the pain element.
Strictly speaking I understand sciatica is a symptom rather than a specific condition, illness or disease.
Whilst trying to get to grips with this part of the jigsaw, I created a Venn diagram, shown below, which I think illustrates how this strict definition of sciatica fits in with the concepts of radicular pain, radiculopathy, radicular syndrome and neuropathy. Fundamentally, in the strictest sense, sciatica is a subset of radicular pain, as radicular pain is pain produced from the irritation of a nerve root, and sciatica is the pain produced by one or more of 5 nerve roots, the sciatic nerve roots. (I understand there is some debate as to which nerve roots contribute to sciatic pain, but this is beyond the scope of this post). Strictly speaking sciatica is only pain though, and any associated neurological deficits (radiculopathy) are separate to that, as indicated in the diagram.
A pragmatic view of sciatica
Many clinicians and Internet articles refer to sciatica as including both the pain element and the neurological deficits such as numbness, reflex loss and motor weakness.
I’m aware that the rheumatologist who diagnosed me with sciatica knew that I experienced numbness and reflex loss, and I am certain that her use of the term ‘sciatica’ was intended to encompass both the radicular pain I was suffering and the radiculopathy (numbness and reflex loss).
I’m not a clinician and so I can’t argue out whether this is correct or not, but as a patient I can accept that if I take a pragmatic view of the differing views about the terminology of sciatica, and allow myself to move away from the strict definition of sciatica, that an understanding of sciatica as encompassing the two elements, radicular pain and radiculopathy, works for my situation, and me. Both the radicular pain and radiculopathy in my case are centred on the S1 root nerve, and the two together explain my diagnosis of sciatica.
A revised Venn diagram for this situation is below:
I will use this pragmatic description of sciatica from now on.
So there we have it, this is my simple understanding of radicular pain radiculopathy and sciatica.
