What is Cauda Equina Syndrome (CES)?

Cauda Equina Syndrome (CES)

Cauda equina syndrome (CES) is a rare but serious neurological condition characterized by dysfunction of the sacral and lumbar nerve roots within the vertebral canal due to compression, producing impairment of bladder, bowel, or sexual function along with perianal or saddle numbness. 1

Definition and Pathophysiology

• CES results from compression of the nerve roots at the terminus of the spinal cord (cauda equina), most commonly caused by lumbar disc herniation at the L4-L5 and L5-S1 levels 1
• Other etiologies include neoplasm, infection/inflammation, spinal stenosis, and hemorrhage 1
• The pathophysiology involves direct mechanical compression of nerve roots and potential venous congestion or ischemia 2
• CES occurs in approximately 2% of cases of herniated lumbar discs and is considered a spinal surgical emergency 3

Clinical Presentation

Core Symptoms and Signs

• Urinary retention (90% sensitivity) - most frequent and sensitive finding 4
• Saddle anesthesia (numbness in perineal/genital region) 1, 2
• Bilateral radiculopathy (bilateral radicular pain, sensory disturbance, or motor weakness) 1, 4
• Bowel dysfunction (including fecal incontinence) 1
• Sexual dysfunction 1
• Low back pain with or without radicular symptoms 1

Progressive Stages of CES

1. Suspected CES (CESS): Bilateral radiculopathy with risk of developing CES but without objective evidence yet 1
2. Incomplete CES (CESI): Objective evidence of CES but with retained voluntary control of micturition (may have urgency, poor stream, hesitancy) 1
3. CES with Retention (CESR): Complete urinary retention and overflow incontinence - considered a "white flag" indicating advanced disease 1

Diagnostic Approach

• MRI lumbar spine without IV contrast is the imaging study of choice due to its ability to accurately depict soft-tissue pathology, assess vertebral marrow, and evaluate spinal canal patency 1
• Urgent MRI assessment is recommended for all patients presenting with new-onset urinary symptoms in the context of low back pain or sciatica 1
• CT lumbar spine without IV contrast can be used if MRI is contraindicated, with 50% thecal sac effacement on CT predicting significant spinal stenosis 1
• CT myelography can be useful for surgical planning in patients with CES and significant spinal stenosis 1

Clinical Pitfalls to Avoid

• Delayed diagnosis can occur in patients without urinary retention, with a probability of CES approximately 1 in 10,000 among those with low back pain 4
• Late recognition of CES by the time "white flag" symptoms appear (complete incontinence, perineal anesthesia) may result in permanent damage 1, 4
• No single symptom or sign has high positive predictive value in isolation, making diagnosis challenging 4
• Early signs and symptoms of developing CES may be subtle or attributed to common postoperative findings in surgical patients 2

Management

• Urgent surgical decompression is the definitive treatment for CES 2, 5
• Patients treated at the CESI stage typically have better outcomes with normal or socially normal bladder and bowel control 1
• Patients treated at the CESR stage may improve (48-93% of cases), but many have severe impairment requiring intermittent self-catheterization, manual evacuation of feces, and/or bowel irrigation 1
• Only a minority of patients with severe deficits post-CES return to work 1

Prognosis

• Outcomes are significantly better when surgical intervention occurs before complete loss of bladder function 1
• Recovery of function is more likely if there is some preservation of perineal sensation preoperatively 1
• The trend shows better outcomes with surgery at any time from 12-72 hours post-CESR compared to further delayed surgery 1
• Long-term morbidity can include permanent neurological deficits affecting bowel, bladder, and sexual function 5