Sciatica

Sciatica (also known as lumbosacral radicular syndrome, ischias, nerve root pain, and nerve root entrapment) is pain in the distribution of the sciatic nerve, ie felt in the thigh and, most importantly, below the knee (1). A pain that is not felt below the knee is not sciatica. Characteristically sciatica is exacerbated by coughing, straining, sneezing, or laughing (2).

The lifetime incidence of sciatica varies from 13-40% while the annual incidence of an episode of sciatica can be between 1-5% (2).

Sciatica is rarely due to a sciatic nerve disorder. It is usually referred pain, either from the dural sleeve of a lumbar or sacral nerve root, or, from an abnormal joint:

• dural root pain:
  • intense pain
  • often accompanied by numbness and paraesthesia
• joint or ligament pain:
  • inconstant pain
  • usually no neurological signs
• an estimated 5%-10% of patients with low back pain have sciatica
• annual prevalence of disc related sciatica in the general population is estimated at 2.2%

Indicators of possible sciatica have been outlined (1):

NICE suggest (3):

Assessment of low back pain and sciatica

• consider alternative diagnoses
  • consider alternative diagnoses when examining or reviewing people with low back pain, particularly if they develop new or changed symptoms. Exclude specific causes of low back pain, for example, cancer, infection, trauma or inflammatory disease such as spondyloarthritis

Risk assessment and risk stratification tools

• consider using risk stratification (for example, the STarT Back risk assessment tool) at first point of contact with a healthcare professional for each new episode of low back pain with or without sciatica to inform shared decision-making about stratified management

Based on risk stratification, consider:

• simpler and less intensive support for people with low back pain with or without sciatica likely to improve quickly and have a good outcome (for example, reassurance, advice to keep active and guidance on self-management)
• more complex and intensive support for people with low back pain with or without sciatica at higher risk of a poor outcome (for example, exercise programmes with or without manual therapy or using a psychological approach).

Reference:

• (1) Koes BW et al. Diagnosis and treatment of sciatica. BMJ. 2007 Jun 23;334(7607):1313-7.
• (2) Stafford MA et al. Sciatica: a review of history, epidemiology, pathogenesis and the role of epidural steroid injection in the management. British Journal of Anaesthesia 2007 99(4):461-473
• (3) NICE (October 2020). Low back pain and sciatica in over 16s: assessment and management