1. Conus Medullaris and
Cauda Equina Syndromes
Temple University Hospital
November 22, 2006
Presented by Darric E. Baty, M.D.

2. Outline of Discussion
• Introduction
• Anatomical Overview
• Conus Medullaris Syndrome
• Trauma As An Etiology
• Cauda Equina Syndrome
• Questions

3. Introduction
• Conus medullaris and cauda equina
syndromes are clinical entities
– Diagnosis based on clinical findings
• History and Physical Examination
– Diagnosis prompts emergent acquisition of
appropriate radiographic workup
• Exclude psychogenic causes
• Identify the pathology to aid in formulation of a
treatment plan
– Etiology is variable

4. Introduction
• What’s the Difference?
– Idealistically
• Patients with conus medullaris syndrome typically present
with symptoms consistent with:
– Spinal cord compression
– Spinal cord dysfunction
– “Intrinsic pathology”
• Patients with cauda equina syndrome typically present with
symptoms consistent with:
– Lumbosacral radiculopathies
– “Extrinsic pathology”
– Practically
• There is much overlap in symptomatology
• Both require complete evaluation, including imaging, to
manage appropriately

5. Anatomical Overview
• For Zak • For Bong Soo

6. Anatomical Overview

7. Conus Medullaris Syndrome
• Definitions
– Historically (i.e., in the “pure, classic” syndrome) defined as
signs consisting of:
• Paralytic bladder incontinence
• Bowel incontinence
• Impotence
• Perineal sensory changes
• Absence of lower extremity weakness
– Presently, a constellation of signs and symptoms including:
• Bowel dysfunction
• Bladder dysfunction
• Sexual dysfunction
• Poor rectal tone
• Perianal sensory changes
• Sometimes, lower extremity weakness

8. Conus Medullaris Syndrome
• Etiologies
– Tumor
– Vascular lesion
– Diabetic neuropathy
– Trauma
– Disc herniation

9. Conus Medullaris Syndrome
• Symptoms
– Back pain
– Unilateral or bilateral leg pain
– Bladder dysfunction
– Bowel dysfunction
– Sexual dysfunction
– Diminished rectal tone
– Perianal sensory loss
– Lower extremity weakness

10. Trauma As An Etiology

11. Trauma As An Etiology
• Acute Spinal Cord Injury Syndromes in Trauma Patients
– Complete spinal cord injury
• ASIA/IMSOP Grade A
• Unilevel: no zone of partial preservation
• Multiple level: zone of partial preservation
– Incomplete spinal cord injury
• ASIA/IMSOP Grades B, C, and D
• Cervicomedullary syndrome
• Central cord syndrome
• Anterior cord syndrome
• Posterior cord syndrome
• Brown-Séquard syndrome
• Conus medullaris syndrome
– Complete cauda equina injury
• ASIA/IMSOP Grade A
– Incomplete cauda equina injury
• ASIA/IMSOP Grade B, C, and D
– Reversible or transient syndromes
• Cord concussion
• Burning hands syndrome
• Contusio cervicalis
• Hysteria

12. Trauma As An Etiology
• Conus Medullaris Syndrome: Trauma
Definition
– Combination of upper and lower motor neuron
deficits, with initial flaccid paralysis of the legs
and anal sphincter

13. Trauma As An Etiology
• Conus Medullaris Syndrome: Trauma
Symptoms
– Acute Phase
• Flaccid paralysis of the legs
• Paralysis of the anal sphincter
– Chronic Phase
• Muscle atrophy of the legs
• Lower extremity spasticity
• Lower extremity hyperreflexia
– Extensor plantar response may be present
• Development of a low-pressure, high-capacity neurogenic
bladder
– Sensory deficits are variable

14. Cauda Equina Syndrome
• Definitions
– Historically
• Bilateral sciatica
– Expanded to include unilateral sciatica
• What about a central disc herniation at L5-S1 sparing the
motor and sensory roots of the lower extremities but affecting
bowel and/or bladder function?
• The frequency of daily urination is much greater than bowel
evacuation, so…
– Presently
• Bladder dysfunction with a decrease in perianal sensation

15. Cauda Equina Syndrome
• Etiologies
– Disc herniation
– Disc fragment migration
– Iatrogenic epidural hematoma
• Post LP or spinal anesthesia
• Postoperatively
– Infection
– Tumor
– Trauma

16. Cauda Equina Syndrome
• Symptoms
– Back pain
– Radicular pain
• Bilateral
• Unilateral
– Motor loss
– Sensory loss
– Urinary dysfunction
• Overflow incontinence
• Inability to void
• Inability to evacuate the bladder completely
– Decrease in perianal sensation

17. Cauda Equina Syndrome
• Avoid the Trap
– Acute central disc herniation at L4-5 or L5-S1
• The sacral roots lie centrally within the dural sac
• Sparing of the lumbar, and even S1, roots may be
present
– Total preservation of leg strength possible
– Bowel and bladder may be completely paralyzed
– Perineal anesthesia present
• The sacral roots are very delicate
– Recovery may not occur, even with relatively expeditious
decompression

18. Questions
• Please give two etiologies of conus
medullaris and/or cauda equina syndrome
• Please recall the most common location
for the end of the spinal cord in the adult
human