Herniated Disc


General Information


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Description:

  • Herniated disc can be described as protrusion, extrusion, or sequestration of intervertebral disc from usual anatomic location, which may be asymptomatic, or which may result in radiculopathy or nonradicular pain


Also called:

  • Slipped disc
  • Prolapsed disc
  • Bulging disc
  • Ruptured disc
  • Herniation of nucleus pulposus (HNP)


Definitions:

  • Sciatica – type of radicular pain that originates in lower back and radiates down posterior or lateral thigh; etiology may be disc herniation or other cause


Incidence/Prevalence:

  • High rate of magnetic resonance imaging (MRI)- or computed tomography (CT)-detected disc herniation (20%-36%) among asymptomatic patient population
  • Prevalence of symptomatic herniated disc reported to be 1%-3% in Finland and Italy (Am Fam Physician 2006 Apr 1;73(7):1240)


Causes and Risk Factors

Causes:

  • Disc degeneration associated with normal aging
  • Recent trauma in children (Acta Paediatr 2010 Jan;99(1):19


Pathogenesis:

  • Disc dehydration and increased collagen concentration associated with normal aging may disrupt annular fibers, predisposing disc to herniation of nucleus pulposus
  • Mechanisms of lumbosacral radicular pain include
    • Mechanical compression of nerve root by herniated material
    • Sensitization of nerve root by bioactive molecules, including inflammatory factors


Possible risk factors:

  • Factors associated with increased risk of sciatica include(1)
    • Sedentary lifestyle
    • Chronic cough
    • Pregnancy
    • Smoking
    • Frequent lifting of heavy objects
  • Family history of lumbar disc herniation may increase risk
    • Based on case-control study of 2,010 patients with lumbar disc herniation compared to 2,170 controls
    • Family history of lumbar disc herniation associated with increased risk (odds ratio [OR] 3.55, no p value reported)
    • Reference – Nan Fang Yi Ke Da Xue Xue Bao 2010 Nov;30(11):2488
  • genetic risk factor identified in case-control study, Trp3 allele in collagen IX alpha-3 protein gene present in 12% patients with sciatic pain and lumber disk disease and 5% controls (JAMA 2001 Apr 11;285(14):1843), editorial can be found in JAMA 2001 Apr 11;285(14):1886
  • Increased body mass index (BMI) associated with increased risk for lumbar disc herniation
    • Based on case-control study of 564 patients with lumbar disc herniation compared to 901 population controls
    • Structured personal interviews determined weight at different ages and other lifestyle factors
    • BMI ≥ 24.3 to < 29.21 associated with increased risk (OR 2.1, 95% CI 1.3-3.6)
    • Reference – Arthritis Res Ther 2010;12(5):R193
  • Some cardiovascular risk factors appear associated with increased risk of symptomatic lumbar disc herniation
    • Based on prognostic cohort study
    • 98,407 female nurses without lumbar disc disease at enrollment were followed for 16 years
    • Physician-diagnosed and imaging-confirmed lumbar disc herniation in 2,727 (2.8%) nurses
    • Factors associated with increased risk of lumbar disc herniation included
      • Diabetes (adjusted relative risk [RR] 1.52, 95% CI 1.17-1.98)
      • Hypertension (adjusted RR 1.25, 95% CI 1.11-1.41)
      • High cholesterol (adjusted RR 1.26, 95% CI 1.1-1.44)
      • Having parent with myocardial infarction before age 60 (adjusted RR 1.13, 95% CI 1.02-1.26)
    • Reference – Spine J 2006 Nov-Dec;6(6):684


Factors not associated with increased risk:

  • Lifetime occupational driving patterns did not affect risk for lumbar disc degeneration in study of 45 twins with differing occupational driving patterns (Lancet 2002 Nov 2;360(9343):), commentary can be found in Lancet 2003 Feb 8;361(9356):531


Complications and Associated Conditions

Complications:

  • Acute cauda equina syndrome – neurologic emergency most often caused by large central disc herniation compressing low lumbar and sacral nerve roots
    • Saddle anesthesia
    • Changes in bowel or bladder habits (such as fecal incontinence or urinary retention)
    • Progressive leg weakness (possibly paraplegia)
  • Persistent, long-term back pain


Associated conditions:

  • Degenerative joint disease of the low back
  • Lumbar spinal stenosis
  • Degenerative spondylosis


History and Physical

History:

Chief concern (CC):

  • Herniated disc causing pain typically in back and/or radiating into leg
  • Sensory loss, paraesthesias, or muscle weakness


History of present illness (HPI):

  • Radiating pain involving leg and/or low back, which may be described as
    • Sharp, dull, piercing, aching, burning, or throbbing
    • Severe and function-limiting
    • Worse when bending forward, sitting, coughing, sneezing, or straining
    • Relieved by lying down or walking
    • Worse in leg than in lower back
    • Only in leg and not in back at all
  • Nonradiating lumbar back pain possible
  • Sensory or motor abnormalities in lower extremities, including
    • Cold, tingling, pricking, or numbness
    • Loss of sensation
    • Muscle weakness
  • Patients with cognitive or neurologic impairment may not complain of pain or have typical pain behavior, but may have change in function
  • Ask about “red flag” findings that may indicate serious underlying pathology, or suggest cause other than lumbar disc herniation


Red Flag Symptoms and Findings with Associated Spinal Disorders:

  Cauda Equina  Infection    Fracture    Cancer
Fecal incontinence x
Saddle anesthesia x
Urinary retention x
Immunosuppression x
IV drug use x
Unexplained fever x
Chronic steroid use x x
Osteoporosis x
Significant trauma at any age x
Age > 50 years x x
History of cancer x
Unexplained weight loss, general malaise x
Focal neurologic deficit in lower extremity x x x
Progressive or disabling symptoms x x x
Imaging is highly recommended for patients with positive red flag symptoms