Definition

• Cauda Equina Syndrome: characteristic pattern of neuromucscular and urogenital symptoms which occurs due to the compression of multiple lumbosacral nerve roots below the level of the conus medullaris

Etiology

• Spinal Infection
  • Spinal Epidural Abscess (see Spinal Epidural Abscess, [[Spinal Epidural Abscess]])
  • Tuberculosis (see Tuberculosis, [[Tuberculosis]])
• Spinal Inflammatory Conditions
  • Ankylosing Spondylitis (see Ankylosing Spondylitis, [[Ankylosing Spondylitis]])
  • Chronic Inflammatory Demyelinating Neuropathy (CIDP) (see xxxx, [[]])
  • Paget’s Disease
  • Sarcoidosis (see Sarcoidosis, [[Sarcoidosis]])
• Spinal Stenosis
• Spinal Trauma
• Spinal Tumors
  • Primary Spinal Tumors
  • Metastatic Spinal Tumors

Spinal Cord Anatomy and Physiology

Spinal Cord

• Conus Medullaris: the spinal cord tapers and ends between L1 and L2, with the conus medullaris representing the most distal bulbous part of the spinal cord
  • Blood Supply
    • Spinal arteries (anterior median longitudinal arterial trunk and 2 posterolateral trunks): main supply
    • Radicular Arterial Branches from Aorta: less prominent arterial supply
    • Lateral Sacral Artery: less prominent arterial supply
    • Fifth Lumbar Artery: less prominent arterial supply
    • Iliolumbar Artery: less prominent arterial supply
    • Middle Sacral Artery: less prominent arterial supply
• Cauda Equina (“horse tail”): mass of lower lumbar and S1-S5 nerve roots distal to the conus medullaris (and within the subarachnoid space)
  • Sensory Innervation: to the saddle area (perineal dermatomes) and lower extremity dermatomes
  • Motor Innervation
    • S2-S4 -> inferior rectal nerve -> voluntary muscles of external anal sphincter
    • S2-S4 -> pudendal nerve -> voluntary muscles of urethral sphincter
    • Lower extremity myotomes
  • Parasympathetic Innervation: to the bladder and lower part of the colon (from splenic flexure to the rectum)
    • S2-S4 -> pelvic splanchnic nerves -> detrusor muscle of bladder
  • Compression of the cauda equina technically represents a “peripheral” nerve injury
  • Blood Supply: middle sacral artery
• Filum Terminale: the fibrous (non-neural) extension of the spinal cord, which extends down to the coccyx

Epidural Space

• Posterolateral Epidural Space
  • Anatomy
    • Posterolateral epidural space extends vertically down the spinal canal and contains arteries, venous plexus, and fat
    • Posterolateral epidural space is larger than the anterior epidural space
    • Posterolateral epidural space is larger in the sacral region than it is in the cervical region
• Anterior Epidural Space
  • Anatomy
    • Anterior epidural space is a virtual space under normal circumstances (due to adherence of dura to bone of vertebral bodies from the foramen magnum down to L1)

Clinical

• Areflexia
  • Ankle
• Bladder/Bowel Dysfunction
  • Decreased Anal Tone/Fecal Incontinence
  • Urinary Retention: due to detrusor muscle weakness
  • Urinary Incontinence
• Low Back Pain/Sciatica: sciatica may be unilateral or bilateral
• Variable Lower Extremity Sensory/Motor Dysfunction
  • Lower Extremity Weakness: bilateral or unilateral
  • Lower Extremity Paraplegia: bilateral or unilateral
• Saddle Anesthesia: involving genitals, uretha, anus, and inner thighs
• Sexual Dysfunction

References

• xxxx