Diagnosis and treatment of sciatica
BMJ 2019; 367 doi: https://doi.org/10.1136/bmj.l6273 (Published 19 November 2019) Cite this as: BMJ 2019;367:l6273
- Rikke K Jensen, associate professor1 2,
- Alice Kongsted, professor1 2,
- Per Kjaer, professor1 3,
- Bart Koes, professor1 4
- 1Center for Muscle and Joint Health, Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
- 2Nordic Institute of Chiropractic and Clinical Biomechanics, Odense, Denmark
- 3Health Sciences Research Center, University College Lillebaelt, Odense, Denmark
- 4Department of General Practice, Erasmus Medical Centre, Rotterdam, Netherlands
- Correspondence to R K Jensen rikkekruger{at}nikkb.dk
What you need to know
Sciatica is a clinical diagnosis based on symptoms of radiating pain in one leg with or without associated neurological deficits on examination
Most patients improve over time with conservative treatment including exercise, manual therapy, and pain management
Imaging is not required to confirm the diagnosis and is only requested if pain persists for more than 12 weeks or the patient develops progressive neurological deficits
Urgently refer patients with signs of urinary retention or decreased anal sphincter tone, which suggest cauda equina syndrome
Surgery is an option if symptoms do not improve after 6-8 weeks of conservative treatment. It may speed up recovery but the effect is similar to conservative care at one year
Sciatica is commonly used to describe radiating leg pain. It is caused by inflammation or compression of the lumbosacral nerve roots (L4-S1) forming the sciatic nerve.1 Sciatica can cause severe discomfort and functional limitation.
Recently updated clinical guidelines in Denmark, the US, and the UK highlight the role of conservative treatment for sciatica.234 In this Clinical Update, we provide an overview for non-specialists on diagnosing sciatica and key principles in its management.
The term “sciatica” is not clearly defined and it is often used inconsistently by clinicians and patients.5 Radicular pain and lumbosacral radicular syndrome have been suggested as alternatives.6 In this article, we use sciatica and radicular pain synonymously. Radiculopathy describes involvement of the nerve root, which causes neurological deficit including weakness or numbness.
How do patients present? (Box 1)
Symptoms and signs suggesting sciatica
Unilateral leg pain more severe than low back pain
Pain most commonly radiating posteriorly at the leg and below the knee
Numbness and/or paraesthesia in the involved lower leg
Positive neural tension test with provocation of pain in the affected leg (straight leg raise test/femoral nerve test/slump test)
Neurological deficit associated with the involved nerve root (muscle weakness/absence of tendon reflexes/sensory deficit)
People with sciatica usually describe aching and a sharp leg pain radiating below the knee and into the foot and toes.7 The pain can have a sudden or slow onset and varies in severity. Most people report coexisting low back pain. Disc herniations affecting the L5 or S1 nerve root are more common and cause pain at the back or side of the leg and into the foot and toes.8 If L4 root is affected, pain is localised to the front and lateral side of the thigh.7 Tingling or numbness and loss of muscle strength in the same leg are other symptoms that suggest nerve root involvement.
How common is sciatica?
The prevalence of sciatica varies between studies. In a primary care study in the UK (609 patients) about 60% of patients with back and leg pain were clinically diagnosed with sciatica.9 In a Danish primary care study in patients with low back pain, 2% of patients in chiropractic clinics (947 patients) and 11% in general practices (324 patients) had associated neurological findings confirming sciatica.10
What are the causes?
Compression of the nerve root and resultant inflammation play a role in pathogenesis of sciatica.1 Disc herniation resulting from age related degenerative changes, and rarely trauma, is the commonest cause19 (fig 1). The inflammatory response induces resorption of the herniated disc material, and is thought to be the reason why most people improve without surgery.
Herniated disc with nerve root compromise. Figure reproduced with permission from the Danish Chiropractors’ Association
Foraminal stenosis and, less commonly, soft tissue stenosis caused by cysts, tumours, or extraspinal pathology are other causes.11 Rarely, extraspinal pathology in the lumbosacral nervous plexus such as neoplasm, trauma, infection, or gynaecological conditions, or muscle entrapment such as piriformis syndrome can mimic symptoms of disc herniation.11
Smoking, obesity, and manual labour are modifiable risk factors for the first episode of sciatica as per a recent systematic review (eight studies), and suggest the potential for prevention.12
How is sciatica diagnosed?
Sciatica is largely a clinical diagnosis based on the person’s symptoms and findings on examination. A history of leg pain worse than back pain or pain below the knee should raise suspicion of sciatica. Inquire about the onset and distribution of pain, and associated symptoms such as tingling sensation, numbness, or muscle weakness in the legs.
There is no specific test for sciatica but a combination of positive findings on examination increases the likelihood.13Figure 2 shows examination for radiculopathy in those patients where sciatica is suspected. A recent cohort study proposed clinical criteria of unilateral leg pain, monoradicular distribution of pain, positive straight leg raise test at <60° (or femoral stretch test), unilateral motor weakness, and asymmetric ankle reflex to predict sciatica caused by lumbar disc herniation.14
Physical assessment of lower extremity radiculopathy. Figure reproduced with permission from Nordic Institute of Chiropractic and Clinical Biomechanics
Exclude serious pathology such as cancer, trauma, and infection. Urinary retention and decreased tone of anal sphincter indicate cauda equina syndrome, which should prompt immediate referral.
What is the role of imaging?
Routine imaging is not advised in people with non-specific low back pain with or without sciatica, as per most clinical practice guidelines.15 It can lead to unnecessary tests, referrals, and intervention, and increased costs.1617 Disc herniation is a common age related finding. A recent meta-analysis (14 magnetic resonance imaging (MRI) studies, 3097 individuals) reported disc protrusion in 57% of symptomatic and 34% of asymptomatic individuals and disc extrusion in 7% and 2% of individuals, respectively.18
Consider imaging if symptoms progress for more than 12 weeks, or if the person has progressive neurological deficits or worsening pain.41920Box 2 lists red flags for referral. Based on your practice settings, you may request imaging or refer the patient to a specialist. MRI is preferred over computed tomography as it is safer. Radiography is not useful.21
Red flags for referral
Severe or progressive neurological deficits
Suspicion of cauda equina syndrome with signs of urinary retention and/or decreased anal sphincter tone
Suspicion of cancer or infection
History of trauma
Acute, severe sciatica for epidural injections where patients would otherwise go on to have surgery
Persistent sciatica for 12 weeks from onset of symptoms despite conservative care
People with persistent or recurrent symptoms after treatment sometimes request a repeat MRI. This is not usually helpful as MRI interpretation is difficult after the initial episode and does not appear to change outcomes.22
What is the prognosis?
Most people experience an improvement in symptoms over time with either conservative treatment or surgery.23 In a five year follow-up of a Dutch randomised controlled trial (231 patients), 8% of patients showed no recovery and 23% reported ongoing symptoms that fluctuated over time.24 Low back pain with pain radiating to the leg appears to be associated with increased pain, disability, poor quality of life, and increased use of health resources compared with low back pain alone.10 Severity and duration of symptoms, radiological findings, or patient characteristics do not consistently predict recovery of pain and function with conservative management, as per a systematic review (seven studies).20
About 55% of patients with sciatica reported improvement in pain and disability at one year in a recent UK primary care cohort study (452 patients). Treatment was based on clinical guidelines and included physiotherapy sessions. Eleven per cent of patients were referred to secondary care. Fourteen patients had surgery and 21 received spinal injections. Longer pain duration and patient beliefs that the problem would continue were associated with a poor prognosis.19
How is it managed?
Symptoms can be distressing and affect daily life and productivity. Acknowledge the person’s concerns and fears. Share information about the natural course of sciatica and reassure them that symptoms usually diminish over time. Discuss treatment options, taking into consideration their preferences, to develop a plan.
Conservative treatment
Initial treatment is aimed at managing pain and maintaining function while the compression and/or inflammation subsides.23 Encourage patients to remain active and avoid bed rest23 so that the condition interferes as little as possible with daily life. Ask the person to watch for and report any change in symptoms, such as increasing leg pain or neurological deficits.
Exercise and manual therapy
Exercise reduces intensity of leg pain in the short term, as per a systematic review (five randomised controlled trials)25 but the effects are small. Clinical guidelines from the UK, US, and Denmark recommend exercise therapy and mention a range of exercises, but do not indicate whether one type of exercise is better than another.234 Based on your practice settings, general practitioners, chiropractors, or physiotherapists can guide patients on appropriate exercises. Consider the severity of the person’s pain and their ability when recommending exercises. Discuss the options for supervised or group exercise based on what is feasible for your patient.
Manual therapy, such as spinal mobilisation, can be offered alongside exercise, and may be provided by manual therapists, physiotherapists, and chiropractors based on local practice.23 Acupuncture is not recommended in patients with sciatica.23 Guidelines from the National Institute for Health and Care Excellence (NICE) advise against traction and electrotherapies for patients with back pain with or without sciatica.3
Medication
Pain medications have uncertain benefit for sciatica and can have adverse effects. Discuss their role and use these only very sparsely for a short period of time (weeks rather than months) and in the lowest possible dose for pain relief.26 A systematic review (three trials) found that non-steroidal anti-inflammatory drugs are no more effective than placebo in improving pain and disability, though there is low quality evidence of overall improvement in patients. Corticosteroids may improve symptoms in the short term (six weeks) compared with placebo, as per a systematic review (two trials).27 The results were less favourable in two subsequent trials. An increased risk of adverse events is reported with either treatment.28 Evidence for the use of paracetamol, benzodiazepines, opioids, and antidepressants for patients with sciatica is limited, and their use is not recommended.28 The available evidence does not suggest any benefit with anticonvulsants or biological agents28 compared with placebo.
Spinal injections
Guidelines on spinal injections differ in their recommendations. NICE guidelines3 recommend offering epidural injection of local anaesthetic and steroid in the lumbar nerve root area in people with acute, severe sciatica where they would otherwise be considered for surgery. The Danish national clinical guidelines do not recommend their use as the beneficial effect was estimated to be very low and only short term based on limited evidence.2
Surgery
People with persistent pain for more than 12 weeks from the onset of symptoms despite conservative treatment may be considered for surgery.2 Imaging should confirm lumbar disc herniation at the nerve root level corresponding with findings on clinical examination. Open micro discectomy for removal of disc herniation is the commonest procedure, and minimally invasive surgical techniques such as endoscopic surgery are commonly used. Discectomy rates have increased from a mean of 75 per 100 000 inhabitants in 2007 to 81 in 2015 across 13 European countries as per data from Eurostat, but this varies considerably.29
A systematic review30 (five randomised controlled trials) reports low quality evidence (based on a single trial) that early surgery within 6-12 weeks of radicular pain provided faster relief compared with prolonged conservative care.31 At one and two year follow-ups, there were no differences in any clinical outcomes between surgery and conservative care.233031
Surgery is also indicated in serious or progressive neurologic deficits such as motor weakness or bladder dysfunction.32
Sources and selection criteria
We searched Medline and Cochrane Database of Systematic Reviews from 2007 to 2018 to build on a clinical update published in The BMJ in 2007.28 We used the search terms “sciatica”, “radicular pain”, “radiculopathy”, “disc herniation” ,“nerve root compression”, “prevalence”, “diagnosis”, and “treatment” and focused primarily on clinical guidelines, systematic reviews, and high quality randomised controlled trials.
A patient’s perspective
It started after an episode of flu. One night, I suddenly had a lot of pain in my leg. The next day, I went to the doctor who told me it was my sciatic nerve that was squeezed. I would have liked more information on what that meant and how long it would take to get better.
During the first three weeks I saw four different clinicians because I had a lot of pain. Only the fourth clinician explained to me what it was and told me that it could take at least a few months to recover. This was useful because then I had a timeframe. I know that the course differs from person to person, but it helps to think, “now I only have four weeks left.”
I have been on sick leave and still am. But now I have started to work a little again. I think it’s getting better. I still have pain in my leg, but it is not quite so fierce, and it is not constant pain any more.
Questions for future research
What is the prevalence of sciatica in different populations such as primary and secondary care, as well as in different age groups and in different professions?
What is the natural course and prognosis of sciatica?
What is the optimal conservative treatment plan, including different treatment modalities and duration?
What are the criteria for surgery and optimal timing to consider surgery?
Education into practice
How would you discuss with a person newly diagnosed with sciatica why referral for MRI is not necessary?
At your practice, what is the conservative treatment that patients with sciatica have received in the past 12 months? How have they improved?
Additional educational resources
National Institute for Health and Care Excellence (NICE) guidelines on low back pain and sciatica in over 16s: assessment and management. 2016. https://www.nice.org.uk/guidance/ng59/chapter/Recommendations
National clinical guidelines for the non-surgical treatment of recent onset lumbar nerve root compression (lumbar radiculopathy). Danish Health Authority (in English). 2016. https://www.sst.dk/da/udgivelser/2016/~/media/B9D3E068233A4F7E95F7A1492EBC4484.ashx
Physical examination of lower extremity radiculopathy. Nordic Institute of Chiropractic and Clinical Biomechanics. http://nikkb.com/research/physical-assessment-of-lower-extremity-radiculopathy1
Clinical guidelines for diagnosis and treatment of lumbar disc herniation with radiculopathy. North American Spine Society, 2012. https://www.guidelinecentral.com/sciatica
Information resources for patients
National Institute for Health and Care Excellence (NICE) National clinical guidelines providing recommendations to the public on low back pain and sciatica https://www.nice.org.uk/guidance/ng59/ifp/chapter/Low-back-pain-and-sciatica-the-care-you-should-expect
International Association for the Study of Pain (IASP) provides a list of webpages with resources relevant to patients in pain http://www.iasp-pain.org/PatientResources.
International Society for Advancement of Spine Surgery (ISASS) patient information material on sciatica https://www.isass.org/for-patients/spine-conditions/sciatica/.
How patients were involved in the creation of this article
One of our patients with sciatica shared their perspective and highlighted how more information would have made a difference to her. We have emphasised how clinicians can share information about the condition and prognosis with patients. A patient also kindly reviewed this paper for The BMJ and suggested we discuss the severity of disability and the impact on daily living. We have done so now. We thank these patients for their input.
Footnotes
Contributorship statement and guarantor BK and RKJ conceived the design and are guarantors. All authors wrote and reviewed the article, created the boxes, and helped with the figures. RKJ was the contact for patient involvement. The authors thank Charlotte Jørgensen (patient) who contributed and revised her personal story, and Suzanne Capell, professional English language editor, for editing the manuscript.
Competing interests The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: none.
Further details of The BMJ policy on financial interests are here: https://www.bmj.com/about-bmj/resources-authors/forms-policies-and-checklists/declaration-competing-interests
Provenance and peer review: commissioned; based on an idea from the authors.