Take Home Messages:

It is more useful to refer to sciatica as nerve root pain or Radiculopathy – as these actually describe the leg pain. (The term sciatica will be used here as in the original article.)

Populations who work in physical jobs such as labouring are more likely to report sciatica.

Sciatica in the presence of low back pain predicts a worse outcome than back pain alone.

People with sciatica consume more health resources, are more likely to experience long term disability and will require more time off from work than people who only have back pain.

Rates of sciatica vary greatly between studies. This is largely due to variation in ways of classifying or reporting the condition. More strict definitions result in lower rates of reporting.

Examination by doctors will give low rates of occurrence, although this may be explained by the fact that symptoms of sciatica fluctuate over time.

Why the research matters: 

Low back pain is very common. It will affect 70% of the population at some point over their lives. The severity of symptoms varies greatly.

Leg pain that originates in the lower back is called sciatica. Sciatica is a vey common result of low back pain.

Sciatica is also called:

• Lumbosacral radicular syndrome;
• Radiculopathy;
• Nerve root pain; and,
• Nerve root entrapment or irritation

Sciatica is a symptom of disease and is not actually an illness itself. It is caused by nerves being compressed or irritated as they exit the spine.

The most common cause of this disruption to nerves is from disc problems in the lower back (where discs that act like cushions between bones expand and blow out) or a narrowing of the openings in the back that let nerves through (thus compressing the nerves).

Sciatica causes pain that radiates (or spreads) to the leg, normally to below the knee and into the foot and toes. Pain follows a typical pattern along the skin of the leg that is supplied by nerves from the lower back. Pins and needles are common along the same area, and there may be muscle weakness or a reduction in reflexes in the affected leg. 

Compared to people with low back pain alone, people with sciatica typically have:

• More persistent disease
• Less favourable outcomes
• Consume more health care resources
• Have longer disability times
• Will be absent for work for longer

Because sciatica is a predictor of poor outcomes in low back pain, having a standard definition is useful for identifying at risk individuals.

There are fewer studies on sciatica than on low back pain. As there is poor agreement on how to classify sciatica, there is great variability in the reported rates of sciatica. This prevents researchers from compiling the results of numerous studies to better understand the natural progression of the disease and improve management.

What the research involved:

The authors searched for research that looked at how common sciatica is in the general population.
 

They compared the studies, and looked at things such as:

• The way sciatica was classified, either by doctors or by self reporting
• Whether a doctor had made a diagnosis
• Whether a doctor had conducted a physical examination
• If the sciatica was self reported, or from medical histories

Using this information they investigated factors that contributed to different rates in the reporting of sciatica.

Summary of research findings:

Reported rates for symptoms of sciatica in the studies examined ranged from 1.6% to 43%.

Summarising results from all of the included studies found that 9.9% to 25% of the population are likely to experience sciatica over a 1 year period.

The study also found that if doctors examine the general population then 4.8% of people will be experiencing symptoms of sciatica at any one time. This figure is lower than that seen over one year as symptoms of sciatica come and go over time.

Working populations, especially those in manual labour jobs are more likely to report higher rates of sciatica.

In one study that compared rates of sciatica in nurses and clerks, it was three times more common in nurses.

Factors that made sciatica less likely to be reported were:

• Actual examination and diagnosis by a doctor
• Only including pain that extends below the knee
• Stricter guidelines on self reporting, e.g. only including pain in a particular distribution
• Only including those who had been treated for sciatica
• A requirement of a longer duration of symptoms

The strictest definition of sciatica found the lowest rate of occurrence. This definition was:

• Back pain that travels to the leg
• Pain that lasts more than 2 weeks
• Made worse by coughing, sneezing or deep breaths

Populations of people who have low back pain are more likely to have sciatica than the general population. Sciatica in someone with back pain is predictive of worse health outcomes.

Original research:

Sciatica. Review of Epidemiological Studies and Prevalence Estimates

Kika Konstantinou, PhD, and Kate M. Dunn, PhD

Spine 2008; 33:2464–2472

Link to PubMed abstract