Degenerative Lumbar Spine

Key Points

  • Back pain worse with leaning forward = discogenic back pain
  • Leg pain worse with leaning forward = herniated disc
  • Back pain worse with extension = posterior elements (spondy)
  • Leg pain worse with extension = stenosis
  • Nicotine has increased effect of disc deterioration
  • Vibratory
    • 4-5 Hz (Truck Drivers)
  • Most disc herniations are L4/5, L5/S1 (90+%)
    • next up is L3/4
  • Lumbar and cervical root numbering differs, but pathology is the same (most herniations affect the nerve root number which corresponds with the bottom vertebra, e.g. a C5/6 herniation affects the C6 nerve root)

 

Low Back Pain

  • Mechanical, axial back pain for less than 6 weeks does not need an MRI
    • Mechanical: worse with activity, better with rest
    • Axial: hurts in the back, not down the leg
  • Red flag signs (indications for X-rays and MRI)

    • red flag: pain at night, hurts at rest, weight loss
    • radiates down leg
    • history of cancer
    • patients on steroids (think compression fracture)
    • more than 6 weeks duration
  • To indicate operative treatment, you really want to see pain (+/- sensory and motor symptoms) in a specific nerve root distribution

Physical Exam Findings 

  • Straight Leg Raise Test

    • Specifically for L4, L5, S1 nerve roots 
    • Patient is supine, knee extended, lift leg into hip flexion
      • during this test, the nerve root travels 3-5mm within the foramen, and causes pain as it passes over a herniated disc
    • Positive test is reproduction of symptoms on ipsilateral side
      • reproduction of back pain only is not a positive test, it has to be a reproduction of the same symptoms in a radicular pattern, on the ipsilateral side
  • Contralateral Straight Leg Raise Test

    • Symptoms are in radicular pattern, but on the contralateral side of the leg raised
    • This is specific for axillary (as opposed to posterolateral) disc herniation (side with symptoms)
  • Femoral Tension Sign

    • Prone or on side
    • Knee flexion, hip extension
    • L1, L2, L3