This common condition is usually due to a slipped disc in the lower back. The pain is characterised by pain spreading down from the lower back, through the buttock down the back of the leg into the calf or foot. This is called sciatica. If the pain goes down the front of the thigh it called femora. The pain is usually severe in the early stages and feels like an electric shock in the leg. It may be made worse by coughing or sneezing. It is often associated with altered sensation or ‘pins and needles’ in the leg or foot. Occasionally there may be weakness of the affected leg or foot.
**If you develop severe pain in both legs, difficulty in passing urine, incontinence, or loss of sensation around your genitals, then you should attend your nearest A&E department as a matter of emergency**
- 90% of patients improve following surgery, with the majority seeing complete resolution of their sciatica
- A few patients will have a technically successful operation but continue to have symptoms due to persisting nerve injury
- A few patients will go on to develop scar tissue or a recurrent disc prolapse, causing recurrent symptoms which can be difficult to manage
The most common cause of sciatica is a prolapsed lumbar disc. This occurs when the soft gelatinous centre of the disc ruptures backwards to squash the nerves in the back. This may require surgery – see treatments - lumbar microdiscectomy (link).
Other causes including ‘wear and tear’ degenerative arthritic disease in the joints and ligaments of the spine may cause narrowing around the nerves. This may require surgery (lumbar foramenotomy – link) or injection therapy (see nerve root injection – link).
In addition to an outpatient assessment and examination you may require an MRI scan if your symptoms persist. (Most patients with a slipped disc will improve without surgical treatment within 6 weeks). An MRI scan is a powerful magnet that creates a picture of your spine without any radiation exposure. The scanner is a long tunnel. The modern scanners now available are less narrow and do not cause claustrophobia for most patients. It is still fairly noising during the scan however as the magnet clicks on and off.