What is the etiology of cauda equina syndrome?

From the Guidelines

Cauda equina syndrome is primarily caused by lumbar disc herniation at the L4-L5 and L5-S1 levels, which is the most common etiology. The etiology of cauda equina syndrome (CES) can be attributed to various causes, including:

• Lumbar disc herniation, particularly at L4-L5 and L5-S1 levels, as the most common cause 1
• Neoplasm, infection/inflammation, spinal stenosis, and hemorrhage as other significant etiologies 1
• Other less common causes, such as trauma, spinal infections, inflammatory conditions, postoperative complications, and spinal hematomas

The pathophysiology of CES involves compression of the sacral and lumbar nerve roots within the vertebral canal, leading to impairment of bladder, bowel, or sexual function, and perianal or saddle numbness 1. The symptoms of CES can include back pain with or without radicular symptoms, weakness in the lower limbs, sensory changes or numbness in the lower limbs, or absent lower limb reflexes 1. Prompt diagnosis and intervention are crucial to prevent permanent neurological deficits, making CES a true surgical emergency.

From the Research

Etiology of Cauda Equina Syndrome

The etiology of cauda equina syndrome is multifactorial, involving various compressive and non-compressive causes. Some of the key causes include:

• Lumbar disc herniation, which is the most common cause, accounting for approximately 45% of all cases 2
• Spinal stenosis, which can cause compression of the nerve roots 3
• Spinal neoplasms, which can compress the cauda equina nerve roots 3
• Non-compressive etiologies, such as ischemic insults, inflammatory conditions, spinal arachnoiditis, and other infectious etiologies 3
• Space-occupying lesions within the canal of the lumbosacral spine, which can cause direct mechanical compression and venous congestion or ischemia 4

Pathophysiology

The pathophysiology of cauda equina syndrome is not fully understood but is thought to be related to damage to the nerve roots composing the cauda equina from direct mechanical compression and venous congestion or ischemia 4. The compression of the cauda equina nerve roots can cause impairment of impulse propagation and changes in neurotransmitters in the spinal cord 3.

Clinical Presentation

The clinical presentation of cauda equina syndrome can vary, but common symptoms include:

• Low back pain
• Sciatica
• Sensorimotor deficits
• Bowel and bladder dysfunction
• Saddle anesthesia of the perineum
• Bilateral lower extremity pain, numbness, and weakness 5, 2, 4, 6