Lumbar Disc Herniation

Etiology

• Most Common:
  • L5/S1 90%
  • 4-5th decade
  • Male to female 3:1
    
• 90% improved over time
  
• Sequestered most likely to resorb

Nerve Root Anatomy

• Cervical root travels underneath a mismatched pedicle (above)
  
• Lumbar nerve root travel under associated pedicle
  
• Cervical roots horizontal, so C5/6 will hit C6
  
• Lumbar nerve roots are vertical, l4/5 paracentral will hit L4 with lateral herniation hitting L5

Classifications

• Central prolapse: back pain only
• Posterolateral (MC): PLL weakest
• Foramina (far lateral or extraforaminal): l4/5 hit l4
• Axillary: hits both roots
• Protrusion: bulging nucleus contained within annul
• Sub-anular extrusion: annular extrusion: annulus intact but fragment above or below disc
• Trans-anular disc herniation: fragment ruptured through annulus but maintains continuity within disc space
• Sequestration: disc material herniates through annulus and is no longer continuous with disc space

Provocative Tests

• Straight leg Test: tension on L5 and S1
  
• Contralateral SLR
  
• Leseague: SLR with dorsiflexion of ankle
  
• Bowstring: SLR with compression of popliteal fossa
  
• Kernig: pain with neck flexion, hip flexion leg extension
  
• Naffziger test: pain with coughing
  
• Milgram: pain reproduced with straight leg elevation for 30 seconds

Imaging

• XR:
  • Loss of lordosis, loss disc height, lumbar spondylosis
    
• MRI w/o gas:
  • Can be abnormal in asymptomatic person, pain >1 month, or red flags
    
• MRI with gadolinium:
  • Revision surgery
  • Distinguish post surgical fibrosis(enhances with gadolinium) vs recurrent herniated disc

Non Operative Treatment

• 90% of LDH resolved at 6 weeks and 12 weeks
• Rest, PT , NSAIDS – first line 90% improve
• Avoid bed rest
  
• NO EVIDENCE that oral steroids help
• Epidural injections does have some pain relief
  
• Selective nerve root corticosteroid injection: 2nd line, (epidural or selective nerve block), long lasting improvement

Operative Treatment

• Surgery proves greater improvements in pain and disability in the 1st 2 years vs nonsurgical improvements
  • microscopic discectomy just as effective as open discectomy
• Laminectomy and discectomy (microdiscectomy):
  • disabling pain >6 months, progressive and significant weakness, caudal equine syndrome – return to medium to high intensity activities at 4-6 weeks
• Outcomes better with surgery
  
  • Positive predictors of good outcome:
    • leg pain chief complaint
    • +SLR
    • corresponding weakness and MRI
    • absence of joint problems, age >41
  • Negative:
    • WC
    • smoking
• Far lateral microdiscectomy:
  • Far lateral herniation, use paraspinal approach of Wilts
• Complications:
  • Dural tear, recurrent HNP, disci tis, vascular catastropher: breaking through anterior annulus and injuring vena cava/aorta
• Revision surgery has equal outcomes as primary surgery that is – equal pain and equal function