Lumbar Disc Herniation

Aka: Lumbar Disc Herniation, Lumbar Disc Disease

1. Epidemiology
   1. Ages affected
      1. Most common ages 30 to 50 years
      2. Rarely occurs before age 20 years
   2. Most common spinal levels affected (95% of lumbar disc)
      1. Vertebral level L4-5
      2. Vertebral level L5-S1
2. Mechanism
   1. Progressive degeneration of disc nucleus pulposus
      1. Results from normal aging or repetitive trauma
   2. Protrusion of disc (most commonly posterior-lateral)
      1. Herniation affects spinal root one level below
   3. Other Changes: Spondylosis (Chronic disc deterioration)
      1. Spur Formation
      2. Disc space narrowing
      3. Facet joint degeneration
3. Complications
   1. Cauda Equina Syndrome
4. Symptoms
   1. Usually insidious onset
      1. Acute trauma may have preceded symptoms
   2. Low Back Pain (deep aching)
      1. Aggravated by activity, coughing, and sneezing
      2. Relieved by rest
      3. Localized to affected disc
   3. Intense Radicular Pain
      1. See Sciatica
      2. Referred pain to iliac crest or buttock
      3. Radiation of pain down posterior thigh and calf
      4. Pain may radiate into foot
   4. Paresthesias
      1. Numbness or tingling in distal extremity
5. Signs
   1. Restricted low back range of motion
   2. Pain exacerbated by bending to affected side
   3. Local tenderness and muscle guarding
   4. Posturing to avoid pressure on disc
      1. Bent away from affected side
      2. Hip and knee flexed on affected side
   5. Nerve Root Tension Tests
      1. Straight Leg Raise
   6. Neurologic Examination
      1. Deep Tendon Reflexes
         1. L4 Nerve Root (L3-4 disc): Patellar Reflex
         2. S1 Nerve Root (L5-S1 disc): Achilles Reflex
      2. Motor Exam
         1. L4 Nerve Root (L3-4 disc): Ankle dorsiflexion
         2. L5 Nerve Root (L4-5 disc): Great toe dorsiflexion
         3. S1 Nerve Root (L5-S1 disc): Ankle plantar flexion
      3. Sensory Exam
         1. L4 Nerve Root (L3-4 disc): Medial malleolus
         2. L5 Nerve Root (L4-5 disc): Dorsal third metatarsophalangeal joint
         3. S1 Nerve Root (L5-S1 disc): Lateral heel
6. Diagnosis
   1. Findings with strongest Positive Predictive Value for Lumbar Disc Disease
      1. Symptoms: Sciatica pain associated with:
         1. Pain in leg worse than back
         2. Typical dermatomal distribution of pain
         3. Pain provoked by valsalva maneuver
      2. Exam findings
         1. Crossed Straight Leg Raise positive
         2. Weak ankle dorsiflexion
         3. Absent ankle reflex
         4. Calf muscle wasting (late finding)
   2. Findings with strongest Negative Predictive Value for Lumbar Disc Disease
      1. No Sciatica
      2. Negative Straight Leg Raise
7. Differential diagnosis
   1. See Sciatica
   2. See Low Back Pain Red Flags
   3. See Musculoskeletal Low Back Pain
   4. Spinal Cord Tumor
      1. Consider especially in age under 20 or over 60 years
      2. Relentless pain aggravated or not relieved with rest
8. Management: Rehabilitation
   1. See Lumbar Disc Disease Management
   2. See Low Back Rehabilitation
   3. See Low Back Muscle Fusion Rehabilitation
9. Course
   1. Spontaneous recovery is the rule (90% in 6 weeks)
   2. Long-term outcomes are not improved with surgery (outcomes the same at 2 years)
10. References
    1. Gregory (2008) Am Fam Physician 78(7):835-44
    2. Humphreys (1999) Am Fam Physician 59(3):575-82
    3. McCall (2000) Radiol Clin North Am 38(6):1293-309
    4. Milette (2000) Radiol Clin North Am 38(6):1267-92