- Most patients with sciatica do not require immediate diagnostic imaging.
BACKGROUND & OBJECTIVE
Sciatica (also called radicular pain) is common, with 60% of patients with low back pain presenting with leg pain features (1). However, sciatica represents only one of the subsets of nerve root involvement that a clinician may see in practice.
This paper is a clinical update on the diagnosis and management of sciatica. For ease of clarity, this paper and review will discuss sciatica together with the remaining radicular syndromes.
First line care should consist of reassurance, advice to stay active and resume activities as possible, as well as exercise.
Differentiating sciatica from other radicular syndromes A thorough history and clinical examination is required to identify the key clinical features that distinguish three subsets of nerve root involvement: sciatica (radicular pain), radiculopathy, and spinal stenosis (2). Differential diagnosis is complex and clinical features are highly variable in practice.
Sciatica or radicular pain simply refers to low back pain-related leg pain. True radicular pain represents a small proportion of LBP-related leg pain presentations. In sciatica presentations, the leg pain is typically worse than the back pain; the quality of leg pain is often referred to as sharp, lancinating or a deep ache aggravated with cough, sneeze or strain; and pain location is often unilateral with dermatomal concentration (below knee for L4, L5, S1). Common physical examination signs include positive nerve tension tests for upper lumbar roots (prone knee bend) or lower roots (straight leg raise and crossed straight leg raise).
Radiculopathy refers to nerve root dysfunction and is signified by dermatomal sensory disturbances, weakness of muscles innervated by that nerve root and hypoactive muscle stretch reflex of the same nerve root. It frequently co-exists with sciatica, but can present as a separate diagnostic entity. The key physical examination finding is myotomal weakness.
Symptomatic spinal stenosis refers to neurogenic claudication features aggravated by extension activities including walking and standing, and eased by flexion activities including forward flexion and sitting. It can present as degenerative in older patients and acquired or congenital in younger patients. A neurological examination is often normal.
Role of imaging
Most patients with radicular syndromes do not require immediate diagnostic imaging and can be managed in primary care. Prompt referral to a spinal surgeon is always indicated for patients who have severe or progressive neurological deficits.
Prognosis and surgery
Radicular syndromes show similar outcomes after non-pharmacological approaches (e.g. education and exercise) and surgery (3-5). For patients with disabling symptoms of longer than six weeks’ duration with a lack of response to non-operative management, specialist referral (rheumatologist, rehabilitation physician, spinal surgeon) can also be considered.
Laminectomy for radiculopathy may shorten the duration of symptoms, but outcomes at 12 months are similar to non-operative treatment and surgery is associated with an increased risk of further surgery. Decompression surgery for symptomatic central lumbar canal stenosis may improve symptoms, but currently there is a lack of high-quality evidence for its superiority over non-operative management.
First line care should consist of reassurance, advice to stay active and resume activities as possible, as well as exercise (if the patient is slow to recover or has muscle deficits). Manual therapy (spinal manipulation or mobilisation) can be provided as part of a package with exercise.
Second line care may progress to more complex medications, including neuropathic pain medication and oral steroids. However, the efficacy and safety of both interventions is unclear.
The use of spinal injections is controversial, and recommendations vary across clinical guidelines. The most up to date systematic review found that spinal injections were associated with immediate reductions in pain and improvements in function over placebo; but the benefits were small and short-term.
- Do not image unless there are serious or progressive neurological deficits.
- Start with conservative management – reassurance, advice to stay active, exercise with or without manual therapy.
- Be cautious with the use of medicines and injections as evidence is uncertain regarding risk:reward ratio.
Jensen R, Kongsted A, Kjaer P, Koes B (2019) Diagnosis and treatment of sciatica. BMJ, 19,367.