Low Back Pain - Introduction - Spine

Introduction

Low back pain affects 50-80% of population in lifetime
- $100 billion in annual cost
- second only to respiratory infection as cause to visit doctors office
Etiology
- muscle strain
  - most common cause of low back pain
- most common degenerative disorders
  - lumbar spinal stenosis
  - lumbar disc herniation
  - discogenic back pain
Risk factors
- obesity, smoking, gender
- lifting, vibration, prolonged sitting
- job dissatisfaction
Red flags
- infection (IV drug user, h/o of fever and chills)
- tumor (h/o or cancer)
- trauma (h/o car accident or fall)
- cauda equina syndrome (bowel/bladder changes)
Outcomes
- 90% of low back pain resolves within one year

Presentation

Symptoms
- axial pain
  - musculogenic
    - most common cause of back pain
    - associated with activity
    - characterized by stiffness and difficulty bending
  - discogenic pain
    - controversial
    - confirmed by discogram
  - mechanical pain
    - caused by
      - facet degeneration
      - micro and macro instability
    - worse with activity such as lifting objects and prolonged standing
  - sacroiliac symptoms
    - pain originating from sacroiliac joint
- peripheral / neurogenic
  - radicular pain
    - unilateral leg pain
    - usually dermatomal
  - referred pain
    - buttocks
    - posterior thighs
    - inguinal region (think L5-S1)
  - neurogenic claudication
    - pain in buttock and legs that is worse with prolonged standing
    - fairly specific for spinal stenosis
  - myelopathy
    - clumsiness in hands
    - gait instability
    - due to injury of spinal cord (~ L1 or above)
  - conus medullaris syndrome
  - cauda equina syndrome
    - bilateral leg pain
    - LE weakness
    - saddle anesthesia
    - bowel/bladder symptoms
  - spinal cord injury
    - incomplete
    - complete
Wadell Signs
- system to evaluate non-organic back pain symptoms,
- clinically significant if three positive signs are present
  - superficial and non-anatomic tenderness
  - pain with axial compression or simulated rotation of the spine
  - negative straight-leg raise with patient distraction
  - regional disturbances which do not follow dermatomal pattern
  - overreaction to physical examination

Imaging

Radiographs
- indications for radiographs
  - pain lasting > one month and not responding to not nonoperative management
  - red flags are present
MRI
- highly sensitive and specific
- high rate of abnormal findings on MRI in normal people

Positive MRI Findings in Asymptomatic Patients
Age	% HNP	% Disc Bulge	% Degeneration
20-39	21	56	34
40-59	22	50	59
60-79	36	79	93

Differential

Neck and arm pain
- trauma
- cervical spondylosis
- metastatic disease / infection
- cervical radiculopathy
- cervical myelopathy
- ankylosing spondylitis
Thoracic back and rib pain
- trauma
- metastatic disease / infection
- thoracic disc herniation
- osteoporotic comression fracture
- trauma
Low back pain
- muscles strain
- disc herniation / discogenic pain
- degenerative spondylolithesis
- spinal stenosis
- lumbar radiculopathy
- abdominal aortic aneurism
Sacroiliac pain
- SI infection
- ankylosing spondylitis
Sacral pain
- coccydynia
- sacral insufficiency fracture

Treatment

Treatment dictated by cause of pain.