Cauda Equina

• Cauda equina


  Central aspect of most concern is S2-4
• S2-S4

  • Innervates bladder
  • Innervates bowel
  • Prolonged Compromise leads to irreversible deficits
• Mechanical nerve root syndrome

  • Spondylosis degenerative changes
  • Disc herniation
  • Central
  • Posteriomedial
  • Posteriolateral
  • Bertoletti's syndrome
• Cauda equina syndrome affects 0.5% of disc herniations
• Cauda equina syndrome


  • Affects bladder more than bowel
  • Can be due to non-mechanical space occupying lesions
• Types of cauda equina syndrome

  • Type 1 = Acute onset as early/first symptoms of disc herniation
  • Type 2 = End point of long history of low back pain with/without leg radicular symptoms
  • Type 3 = Insidious, slow, chronic progression to numb urinary symptoms
• Patients may present late if symptoms are slow, insidious and well tolerated, or if they have pre-existing bladder/bowel control problems, or are embarrassed by symptoms
• Red flags for cauda equina syndrome

  • Bilateral sciatica
  • Severe or progressive bilateral neurological deficit of legs
  • Difficulty initiating micturition or impaired sensation of urinary flow
  • Loss of sensation of rectal fullness
  • Perianal, perineal or genital sensory loss
  • Laxity of anal sphincter
• Cauda equina syndrome requires emergency MRI referral
• Focused neurological examination


  1. Sensation in legs

  2. Motor reflexes in lower limbs

  3. Motor power in lower limbs

  4. Sensation in anal and perineal region

  5. Anal tone
• Questions to ask?


  Do they have any sense of bladder filling?

  Can they feel urine passing?

  Can they stop urine passing midstream at will?

  Does their bladder leak continually or suddenly pass large volumes?

  Is there any associated rectal disorder?

  Is there any disorder of potency in male?

  Is there any numbness in the perineium?
• What are the common causes of CES??

  Massive Central disc herniation

  congenital narrowed lumbar canal or stenosis

  non-mechanical space occupying lesion