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What is the diagnosis?

Sciatic nerve pain 

• Pearl: Sciatica is a symptom rather than a specific diagnosis. Available evidence from basic science and clinical research indicates that both inflammation and compression are important in order for the nerve root to be symptomatic [6].

What is the mechanism of injury?

Sciatic nerve pain most commonly arises from compression and/or inflammation of lumbar or sacral nerve roots, typically due to herniated intervertebral discs or spinal stenosis. The pathogenesis involves both mechanical and biochemical factors. Mechanical compression distorts the nerve root or its sensory ganglion, while biochemical irritation results from inflammatory mediators (such as cytokines) released by degenerated disc material, which can sensitize and activate nociceptive pathways [3,5].

What physical exam findings are expected?

The most characteristic finding is radicular pain reproduced by the straight-leg-raising test (Lasègue’s test), where passive elevation of the extended leg in the supine position elicits pain radiating from the buttock down the posterior thigh and below the knee, usually between 30–70 degrees of hip flexion, as seen in this video here. The crossed straight-leg-raise test, in which raising the unaffected leg reproduces pain in the affected leg, is highly specific for disc herniation but less sensitive. Neurologic deficits such as motor weakness, sensory loss, or reflex changes (ankle and knee reflexes) may also be present.

• Pearl: Increased pain with Valsalva maneuvers (coughing, sneezing) suggests nerve root involvement [4].

What imaging modalities can be used?

Sciatica is mainly diagnosed by history taking and physical examination. By definition, patients have pain radiating into the leg. Imaging and electrophysiological evidence of nerve-root compression corroborates structural disk or spine disease as the proximate cause of sciatica, but testing is not necessary in a typical case until intervention is required. The nature and location of disk rupture and spinal lesions, such as osteoarthritic disease and spondylolisthesis, lateral recess stenosis, and synovial cysts of the facet joint, can be best seen on magnetic resonance imaging (MRI) without gadolinium. Computed tomography (CT) is performed less frequently but reveals most disk herniations and structural changes of the spine [4].

Image 2. Sagittal MRI of Lumbar spine with disc protrusion; Case courtesy of Bálint Botz, Radiopaedia.org, rID87940

What is the management in the ED?

Nonpharmaceutical treatments, which include warm or cold compresses, are the first line of therapy for sciatica pain. If this fails, then pharmaceutical therapy with NSAIDs (ie. ibuprofen or toradol) can be considered.

• Pearl: Ketoprofen gel for non-specific low back pain and intravenous paracetamol or morphine for sciatica were superior to placebo, whereas corticosteroids were ineffective for both conditions. There was conflicting evidence for comparisons of different pharmacological options and those involving non-pharmacological treatments. Additional trials measuring important patient-related outcomes to EDs are needed [2].

Ultimately, patients should stretch everyday, enroll in physical therapy, and follow up with a pain management specialist if their pain is refractory to the above treatments.

When do you consult Orthopedics?

Orthopedics or spine surgery (depending on local practices) should be consulted if there is evidence of cauda equina, conus medullaris, bowel/bladder dysfunction, or underlying pathology to include malignancy, infection, or fracture [1].