👢 Cauda equina syndrome, Acute foot drop & neurogenic claudication

August 3, 2024

Cauda equina syndrome, Acute foot drop & neurogenic claudication #

Cauda equina syndrome #

• Triad of symptoms - Cauda equina syndrome (CESR) is defined as a triad of symptoms including:

1. bilateral lower limb radicular pain
2. perianal sensory loss
3. insensate urinary retention and subsequent incontinence.

• Often the first symptom is the radiculopathy. Urogenital symptoms last.

• Terms

  • Cauda equina syndrome (CESR)
  • Cauda equina in evolution (CESE) = A patient progressing through these symptoms.
  • Impending cauda equina syndrome (CESI ) = A clinical picture with the absence of the urinary dysfunction.

• Investigation: CESI, CESE and CESR represent a neurosurgical emergency and when seen mandate an urgent MRI scan

• Management:

  • surgical decompression within 24-48 hours.
  • Delays leads to devastating urogenital dysfunction

Danger

Red flags of cauda equina syndrome #

• Bilateral leg neurological deficit
  • major motor weakness
    • knee extension,
    • ankle eversion,
    • or foot dorsiflexion
• Recent-onset urinary retention +/- incontinence
• Recent-onset faecal incontinence
• Perianal or perineal sensory loss
• lax anal sphincter

Acute foot drop #

• An acute painful foot drop suggests compression and may need surgical treatment.

• Painless foot drop is likely a ‘medical’ aetiology such as diabetes.

• Ankle dorsiflexion

  • Muscles
    • tibialis anterior,
    • extensor hallucis longus and
    • extensor digitorum longus.
  • Nerve supply mostly L5, with a few from L4.

• L5 outflow is through common peroneal nerve.

Question

How to differentiate between a foot drop of L5 root aetiology and a foot drop from a common peroneal nerve aetiology?

Feature	L5 Root Weakness	Common Peroneal Nerve Aetiology
Back Pain	Present	Absent
Gluteal Weakness	Present	Absent
Radicular Pain and Paraesthesia	Present in a dermatomal distribution	Pain and paraesthesia limited to the first webspace
Foot Eversion	Relative preservation (normal foot eversion due to peroneus muscle group, L4-S1)	Impaired

• Management
  • early decompression
  • foot drop splints
• Good prognosis, with two-thirds improving by 6 months.

Lumbar canal stenosis #

• Neurogenic claudication
• older patients
• Clinical features
  • Spine extension - Classical feature: walking and standing results in U/L or B/L leg pain/numbness/pins and needles
  • Spine flexion: improves symptoms ‘shopping trolley sign’
  • often vague symptoms - legs feel dead
  • symptoms usually slowly alleviated with rest
  • significant limitation to walking distance
• Differential diagnosis: vascular claudication.
• Pathology
  • often insidiously progresses
  • The compression is mainly from hypertrophy and liagmentum flavum degeneration facet joint to narrow the neural canal and lateral recess.
  • symptomatic when walking due to relative ischaemia of the roots.
• Management
  • antineuropathics are unhelpful.
  • Due to the non-inflammatory nature, steroid injections also unhelpful.
  • Posterior decompression can improve the claudicant symptoms greatly