Cauda Equina Syndrome

Cauda Equina Syndrome (direct translation from Latin cauda equina — horse’s tail) is a life-threatening neurological condition caused by massive and acute compression of the bundle of lumbar, sacral, and coccygeal nerve roots in the lower spinal canal.

Etiology and pathophysiology

A distinctive anatomical feature in humans is that the dense spinal cord ends at the level of the first to second lumbar vertebra. Below this level, within the wide dural sac, only long nerve roots (from L2 to S5) freely pass, their appearance visually reminiscent of a horse’s tail.

The syndrome develops with a sudden and critical narrowing of the spinal canal lumen at the level of the lumbar spine. The absolute leading cause is a massive (sequestered) central herniated intervertebral disc that directly falls into the canal’s lumen and compresses the entire nerve bundle at once. Less commonly, the cause can be a comminuted fracture of the lumbar vertebra or a large epidural hematoma.

Clinical significance

In traumatology and neurosurgery, this diagnosis is categorized as an absolute “red flag” and requires immediate hospitalization. The clinical picture consists of a specific symmetrical triad of symptoms.

The main symptom is “saddle anesthesia” — a complete loss of sensitivity in the perineal area, inner thighs, and genitals. The second critical symptom is severe dysfunction of the pelvic organs: acute urinary retention (the patient does not feel bladder fullness) and fecal incontinence due to sphincter paralysis. The third sign is flaccid paresis of the lower extremities with loss of Achilles reflexes. The condition requires urgent decompressive surgery within the first 24 hours to prevent irreversible disability.