From the Guidelines
Sciatica diagnosis should be based on a combination of medical history, physical examination, and sometimes imaging tests, with a focused examination including straight-leg-raise testing and a neurologic examination to assess the presence and severity of nerve root dysfunction. When diagnosing sciatica, a typical history for sciatica (back and leg pain in a typical lumbar nerve root distribution) has a fairly high sensitivity but uncertain specificity for herniated disc 1. The physical examination should include specific tests such as:
- Straight-leg-raise testing to assess the presence and severity of nerve root dysfunction
- Neurologic examination to evaluate knee strength and reflexes (L4 nerve root), great toe and foot dorsiflexion strength (L5 nerve root), foot plantarflexion and ankle reflexes (S1 nerve root), and distribution of sensory symptoms A positive result on the straight-leg-raise test has a relatively high sensitivity (91% [95% CI, 82% to 94%]) but modest specificity (26% [CI, 16% to 38%]) for diagnosing herniated disc 1. Psychosocial factors and emotional distress should also be assessed because they are stronger predictors of low back pain outcomes than either physical examination findings or severity and duration 1. Imaging tests such as MRI, CT scans, or X-rays may be ordered if symptoms are severe, persistent, or accompanied by concerning signs like bladder/bowel dysfunction. A proper diagnosis is crucial because sciatica is actually a symptom of an underlying condition like a herniated disc, spinal stenosis, or piriformis syndrome, and treatment depends on identifying the specific cause of nerve compression.
From the Research
Sciatica Diagnosis
- Sciatica is a set of symptoms rather than a specific diagnosis, and is caused by a herniated lumbar disc in the vast majority of cases 2
- The most important symptom is lower limb pain radiating below the knee and into the foot and toes 2
- Diagnosis mainly involves history taking and physical examination 2, 3
Imaging and Testing
- Imaging is warranted if there is evidence of an underlying pathology other than disc herniation, such as infection or malignancy, and in patients with severe symptoms that do not improve after 6-8 weeks of conservative treatment 2
- MRI is the preferred imaging modality, as it can visualize soft tissues better than CT and does not expose the patient to ionizing radiation 2
- Testing with X-ray and MRI are key to diagnosing lumbar instability and herniated discs 3
Management and Treatment
- Conservative treatment is generally the first-line option in patients with sciatica 2
- Management includes physical conditioning, proper pain management, and surgery as a last resort 3
- Pain treatment includes analgesics, anticonvulsants and muscle relaxants 3
- A more aggressive approach would include epidural infiltrations and radiofrequency 3
- The effectiveness of surgery in patients with sciatica due to lumbar disc herniations is not without dispute, and future studies should evaluate who benefits more from surgery and who from conservative care 4