Sciatica is a common condition characterised by pain radiating from the lower back down to one or both legs. It occurs when the sciatic nerve, the longest nerve in the human body becomes compressed or irritated. The sciatic nerve originates from the lower lumbar nerves (lumbar 4 and lumbar 5) and the sciatic 1 to 3 nerves. It runs from the lower spine, down the buttock, back of thigh and calf to the feet.
Sciatica is the term used to describe pain arising from compression of the sciatic nerve. This pain is in the distribution of the sciatic nerve (lower back, buttock, back of thigh and calf). This can cause debilitating pain, loss of mobility and function. In severe cases, there can even be weakness of ankle (lumbar 4) dorsiflexion or big toe strength (lumbar 5 or sacral 1).
There are several causes that can lead to sciatic nerve compression. The most common is a herniated disc which occurs when the soft inner material (nucleus pulposus) of the spinal disc protrudes and compresses the sciatic nerve. Another is spinal stenosis which occurs in middle age or elderly patients when the spinal canal narrows due to facet joint arthropathy, ligamentum flavum thickening and disc bulging which compress the lumbar nerves.
Another cause maybe, Spinal stenosis which refers to the narrowing of the spinal canal, which can put pressure on the lumbar nerve roots. This condition often develops as a result of age-related changes in the spine and can cause lower back pain, as well as leg pain and weakness on walking a certain distance (neurogenic claudication).
Less common causes are piriformis syndrome (piriformics muscle in the buttock compresses the sciatic nerve, pelvic fractures or tumors in the pelvic region).
If you have sciatica or neurogenic claudication (leg pain on walking a certain distance), a MRI lumbar spine scan is recommended if the pain is persistent despite rest and analgesia. The MRI scan will show if there is any nerve compression. Most times, the symptoms will resolve with a course of anti-inflammatories and physiotherapy. In severe cases, a decompression surgery might be needed which can be done via a mini-open or endoscopic approach with minimal downtime for recovery.
In summary, back pain and sciatica will usually get better with rest and a short course of analgesia and physiotherapy. If it does not, consulting an orthopaedic spine surgeon is recommended.