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Sciatica

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Ovid: 5-Minute Sports Medicine Consult, The


Sciatica
Kathleen Weber
Basics
  • Sciatica is referred to in the medical literature as lumbosacral radicular syndrome, radiculopathy, or nerve root pain.
  • Sciatica pain radiates from the lower back into the leg. It usually radiates below the knee into the foot in a dermatomal pattern corresponding to the affected nerve root.
Description
Radicular pain in the distribution of a sciatic nerve root (L4, L5, S1, S2, or S3), usually producing symptoms along the posterior or lateral aspect of the lower extremity and extending to the ankle or foot
Epidemiology
  • Lower back pain (LBP) is extremely common in the general population and the athletic population (eg, football, gymnastics, tennis).
  • General population: 5% annual occurrence; 60–90% lifetime incidence (1):
    • Men and women equally affected
    • Common reason to visit primary care physician
    • Leading cause of job-related disability in the U.S.
  • Sciatica:
    • Sciatica is a common cause of pain and disability.
    • Prevalence rates reported in different studies and reviews vary considerably, ranging from 1.2–43% (1).
    • Peaks in the 4th to 5th decades of life
Risk Factors
Occupations or activities that require repetitive lifting or movement in the forward bent-and-twisted position
Etiology
The usual etiology of sciatica pain is the result of direct mechanical compression to the affected nerve root and in part from chemical irritation of the nerve root by chemical substances resulting from the herniated nucleus pulposus.
Commonly Associated Conditions
  • Cauda equina syndrome
  • Urinary retention
  • Motor loss
  • Intractable pain
Diagnosis
History
  • Determine any red flags: Warning signs to increase your clinical suspicion as cited by the Agency for Health Care Policy and Research:
    • Age <20 yrs or >50 yrs
    • History or signs and symptoms of infection or malignancy
    • Unexplained weight loss
    • Immunosuppression
    • Severe or atypical pain
    • Trauma
    • Fracture
    • IV drug use
    • Abdominal pain
    • Significant neurologic deficit
    • Bowel/bladder dysfunction
    • Saddle anesthesia
  • Evaluate and manage any positive red flags.
  • Determine any constitutional signs.
  • Mechanism of injury or inciting incident
  • Length of symptoms
  • Is the pain worsened by Valsalva maneuver, coughing, sneezing?
  • Is the pain unilateral or bilateral?
  • Does the pain radiate below the knee? Into the foot or toes?
  • Psychosocial issues that may add to symptoms and prolong pain
Physical Exam
  • Signs and symptoms:
    • Sharp or “electrical” pain radiating along the sciatic nerve dermatomal distribution (most commonly L4, L5, and S1), usually to the ankle or foot
    • Often associated with dermatomal sensory disturbances, motor weakness, and hypoactive deep tendon reflexes
    • Onset of pain is variable because it can be immediate or within a few hours or days of the inciting event.
    • May complain of radicular symptoms and not localized back pain
    • 95% involve the L5 (most common) or S1 nerve root.
    • Aggravating factors are trunk flexion or rotation, prolonged sitting or standing, coughing, sneezing, or straining during defecation.
    • Muscle atrophy reflects long-standing condition.
  • Physical examination:
    • Detailed neurologic (motor, sensory, and reflexes) and vascular examination includes rectal tone and anal sensation.
    • Criterion for abnormal findings is reproduction of pain in radicular distribution rather than reproducing lower back pain.
    • Straight-leg raise (SLR) of involved leg: Performed in supine position; reproduces sciatic-type pain between 30 and 60 degrees
    • Crossed SLR: Raising the contralateral leg results in reproduction of pain on the affected side and is specific for a herniated disk.
    • Sitting knee extension: Performed while patient is sitting; passive extension of the knee reproduces pain (modification of SLR).
    • Ankle dorsiflexion or chin to the chest: Performed either with SLR or crossed SLR; exacerbates the pain
    • Test specific nerves.
      • Sensory loss:
        • L4: Anteromedial leg, medial malleolus
        • L5: Lateral lower leg, web space between the great and 2nd toes
        • S1: Back of lower leg, lateral aspect of foot, little toe
      • Motor weakness:
        • L4: Knee extension (quads)
        • L5: Extensor hallucis longus (great toe)
        • S1: Foot plantar flexion (toe raises)
      • Reflex (hypoactive):
        • L4: Patellar
        • L5: None
        • S1: Achilles tendon

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Diagnostic Tests & Interpretation
Imaging
  • Anteroposterior and lateral radiographs of lumbar sacral spine usually are not indicated unless
    • Red flags are present (see “History”).
    • Unresolved back pain for 6 wks
    • Back pain with constitutional symptoms and history of IV drug abuse, cancer, or diabetes
  • MRI (preferred study) or CT scan (used primarily when MRI is contraindicated, ie, hardware, pacemaker) or CT myelography:
    • Suspected cauda equina syndrome
    • Abscess
    • Neoplasm
    • 6 wks of failed conservative therapy for sciatica or intractable pain
    • MRI is typically not necessary unless there is intractable pain or neurologic deficits.
  • CT scan is the study of choice for identifying bony vertebral injuries.
  • Abdominal US or CT scan to evaluate for abdominal aortic aneurysm
Differential Diagnosis
  • Ankylosing spondylitis
  • Cauda equina syndrome
  • Extrinsic nerve compression, eg, from wallet or prolonged cycling
  • Facet arthropathy
  • Pathologic, traumatic, or osteoporotic compression fracture
  • Herniation of the nucleus pulposus
  • Infection, eg, osteomyelitis, epidural abscess
  • Neoplasm, primary or metastatic
  • Osteoarthritis
  • Paget disease
  • Piriformis syndrome
  • Sacroiliitis
  • Spinal stenosis
  • Spondylolisthesis
  • Synovial cyst
  • Trauma, eg, hematoma, musculoligamentous strain, fracture
  • Nonspinal causes, eg, abdominal aortic aneurysm, herpes zoster, hip arthritis or bursitis, iliotibial band syndrome, psychogenic, vascular claudication
Treatment
  • NSAIDs, acetaminophen (2)[B]
  • Acute LBP: Avoid inactivity; sciatica: Activity level not found to make a difference (3)[B]
  • 6 wks of conservative management should be tried before obtaining imaging or invasive procedures unless red flags are present or develop (4)[A].
  • Physical therapy may provide benefit in subacute and chronic LBP; studies are inadequate to draw definitive recommendations (5)[B].
  • Epidural steroid injections may provide short-term improvement in pain but do not affect long-term outcomes (6)[A].
  • Patients with lumbar disk herniations that are not responding to conservative management should be considered for diskectomy (4,7)[A].
  • Surgery referral for any suspicion of cord compression, bilateral sciatica, significant or progressive neurologic deficit, or disabling sciatica (7)[A]
  • In the absence of severe intractable pain, neurologic deficits, and/or severe disease, surgery should be avoided.
Additional Treatment
Additional Therapies
  • Physical therapy directed toward restoring motor or strength deficits (5).
  • For the best physical therapy outcomes, both aerobic conditioning and core strengthening are essential.
Complementary and Alternative Medicine
Alternative therapies such as acupuncture, traction, and/or manipulative therapy have not been proven effective in randomized, controlled trials (Cochrane reviews).
Ongoing Care
Patient Education
  • Weight loss is beneficial in overweight and obese individuals.
  • Avoid opioids.
  • Stop smoking.
Prognosis
  • Acute pain is almost always self-limited.
  • Estimated recovery time: 90% within 4–6 wks (4)
References
1. Konstantinou K, Dunn KM. Sciatica: review of epidemiological studies and prevalence estimates. Spine. 2008;33:2464–2472.
2. Roelofs PD, Deyo RA, Koes BW, et al. Nonsteroidal anti-inflammatory drugs for low back pain: an updated cochrane review. Spine. 2008;33:1766–1774.
3. Hagen KB, Jamtvedt G, Hilde G, et al. The updated cochrane review of bed rest for low back pain and sciatica. Spine. 2005;30:542–546.
4. Gibson JNA, Waddell G. Surgical interventions for lumbar disc prolapse. Cochrane Database of Systematic Reviews. 2007;2:CD001350. DOI:10.1002/14651858.CD001350.pub4.
5. Hayden J, van Tulder MW, Malmivaara A, et al. Exercise therapy for treatment of non-specific low back pain. Cochrane Database of Systematic Reviews. 2005;3:CD000335. DOI:10.1002/14651858.CD000335.pub2.
6. Chou R, Atlas SJ, Stanos SP, et al. Nonsurgical interventional therapies for low back pain: a review of the evidence for an american pain society clinical practice guideline. Spine. 2009;34:1078–1093.
7. Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical versus nonoperative treatment for lumbar disc herniation: four-year results for the Spine Patient Outcomes Research Trial (SPORT). Spine. 2008;33:2789–2800.
Additional Reading
Caragee EJ. Persistant lower back pain. NEJM. 2005;352:1891–1898.
Codes
ICD9
724.3 Sciatica


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