What is neurogenic claudication (contrasted with vascular claudication)?
Basics: nerves don't like pressure. Sit like this too long and bad things happen to your common peroneal nerve
Next: the word "Claudication" (Latin: limp) refers to painful cramping and/or weakness. (The name "Claude" means "lame one"; "Clawed" means "scratched one")
It is important to differentiate neurogenic from vascular claudication. The term "neurogenic" refers to the fact that the problem originates from a problem involving the nerves, but the common theme is ischemia: in classic claudication, the muscles are ischemic; in neurogenic, it is the nerves.
Classic/vascular claudication comes from poor blood supply to the legs
Neurogenic claudication is caused by spinal stenosis (itself caused by bone overgrowth, disc protrusion, facet arthritis, or soft tissue proliferation)
As shown, with spinal stenosis the central canal space is much reduced (putting pressure on the nerves)
Neurogenic claudication can cause bilateral or unilateral lateral calf, buttock, or thigh discomfort, pain, and/or weakness. In some patients, it is precipitated by walking or prolonged standing. The pain is typically relieved by flexion of the waist. The cause is believed to be ischemia of the lumbosacral nerve roots secondary to compression from structures such as hypertrophied facets, ligamentum flavum, bone spurs, scar tissue, and bulging or herniated discs.
Vascular claudication is due to a circulatory problem. Bad arterial flow leads to ischemia of the calf muscles. Angiography is definitive and measuring the ABI (the Ankle: Brachial Index), ie the ratio of the leg and arm blood pressures) is a good screening measure.
Neurogenic claudication can be differentiated from vascular claudication, by the following features:
- Neurogenic pain is more proximal,
- Neurogenic pain not always uniformly present
- Neurogenic pain can be present at rest
- Neurogenic pain is not dose dependent (ie blocks walked) and
- may be relieved by postural changes (leaning forward to make more space in the spine---eg bike riding is fine whereas walking is painful).
Basically: vascular claudication causes 'dose dependent calf pain'---walk more, hurt more; stop, feel better. All the time, every time.