13/10/2013 Gavin

Causes of sciatica

Sciatica is a description – not a diagnosis; see our video for more info on this.  Sciatica most frequently causes pain deep in the buttock, but can involve anywhere from there down the back and outside of the thigh, calf or outer leg, top or sole of foot all the way to the big toe.  It does not affect the front or inside of the thigh or the groin – if your pain is there then it’s not sciatica.  It can cause pins and needles, numbness, electric shooting pains, a feeling of running water, cramping, and even a cold foot.  But – what causes sciatica?

“True” Sciatica

In medical/scientific terms, “Sciatica” only refers to pain caused by “pathology” of the sciatic nerve and its tributaries.  The sciatic nerve iteslf, or any of its tributary nerves can be irritated or compressed.  The most common cause of this is a herniated or prolapsed (“slipped”) intervertebral disc pressing on one of the lumbar tributary nerves; but spondylotic boney growths (wear and tear), and gross vertebral misalignments (spondylolisthesis) can also do this.

Irritation of the sciatic nerve as it passes through the pelvis also happens; piriformis syndrome, whereby the piriformis muscle (in the buttock muscles) spasms and effectively “grips” the sciatic nerve is another possibility.

It is possible to have sciatica due to serious disease e.g. a tumour, but this makes up about 0.1% of cases of sciatica.

Sciatica due to Referred Pain

The term “sciatica” is also popularly used to describe any pain in the distribution of the sciatic nerve – not just “true” sciatica.

Referred pain is when you feel pain in an area other than the area that’s actually causing the pain, and when this is not caused by nerve entrapment.  Your sciatic nerve gives off a lot of branches, and these in turn give smaller branches – much like a tree spreading its branches.  Because ultimately all of these branches eventually lead back to the same place, it’s possible for your brain to feel pain from one branch (e.g. the one to the back of your thigh) when it’s actually coming from another branch (perhaps the one to a muscle in your lower back).

So, the referred pain mechanism can account for pain in just about any part of the sciatic distribution that’s coming from another structure getting its nerve supply from any branch of the sciatic nerve.  So, sciatica can be caused by damage to or inflammation of muscle, ligament, tendon, bone, etc.

Why do you get Sciatica?

That depends on which category above you fall into, but true sciatica affects between 13 & 40% of the population at some time in their lives.  Referred sciatica is even more common.   There can be a family pattern of sciatica, taller people are more commonly affected, those with a history of sciatica are more likely to get it again, and some occupations – particularly those involving lots of driving – have an increased risk.

How do you fix sciatica?

Give us a call to get the full correct diagnosis, and make sure you’re following the right plan.  Remember… “Knowledge is Power”!