What is cauda equina syndrome?

From the Guidelines

Cauda equina syndrome is a serious medical emergency that requires immediate attention, and treatment typically involves emergency surgical decompression within 24-48 hours of symptom onset to relieve pressure on the nerve roots and prevent permanent damage. The cauda equina is a bundle of nerve roots located at the lower end of the spinal cord, resembling a horse's tail, and consists of nerve roots that branch off from the spinal cord's lower end, typically at the level of the first lumbar vertebra (L1) 1. These nerve roots travel through the spinal canal before exiting at their respective levels to innervate the lower limbs, pelvic organs, and perineum. Cauda equina syndrome occurs when these nerve roots are compressed, typically due to a herniated disc, tumor, infection, or trauma. Symptoms include severe low back pain, bilateral sciatica, saddle anesthesia (loss of sensation in areas that would touch a saddle when riding), bladder and bowel dysfunction, and lower extremity weakness.

Some key points to consider in the diagnosis and treatment of cauda equina syndrome include:

• The most common cause of cauda equina syndrome is lumbar disc herniation at the L4-L5 and L5-S1 levels 1.
• Other etiologies include neoplasm, infection/inflammation, spinal stenosis, and hemorrhage 1.
• MRI lumbar spine without IV contrast is the preferred initial study for evaluating suspected cauda equina syndrome due to its ability to accurately depict soft-tissue pathology, assess vertebral marrow, and assess the spinal canal patency 1.
• CT lumbar spine without IV contrast can answer the question of whether or not cauda equina compression is present, but MRI is superior in soft-tissue contrast and characterizing the etiology of cauda equina syndrome 1.
• Treatment typically involves emergency surgical decompression within 24-48 hours of symptom onset to relieve pressure on the nerve roots and prevent permanent damage 1.

Overall, prompt recognition and treatment of cauda equina syndrome are crucial to prevent permanent neurological damage and improve outcomes.

From the Research

Definition and Causes of Cauda Equina Syndrome

• Cauda equina syndrome is a rare but serious cause of lower back pain resulting from compression of the cauda equina nerve roots, most commonly by lumbar disc herniation 2.
• It is a condition that affects the nerves in the spine supplying the bladder, bowel, and sexual function 3.
• The syndrome is characterized by varying patterns of low back pain, sciatica, lower extremity sensorimotor loss, and bowel and bladder dysfunction 4.

Symptoms and Diagnosis

• Red flag symptoms, such as bladder dysfunction, saddle anesthesia, and sciatica, should lead to high clinical suspicion of cauda equina syndrome 2.
• Symptoms may include bilateral neurogenic sciatica, reduced perineal sensation, altered bladder function leading to painless urinary retention, loss of anal tone, and loss of sexual function 5.
• Diagnosis is often delayed, which may result in a poor prognosis, and typically involves magnetic resonance imaging (MRI) or computed tomography myelography if MRI is not available 5.
• Postvoid bladder volume assessments can assist in the evaluation of cauda equina syndrome 5.

Treatment and Management

• Urgent decompressive surgery is usually recommended for the best outcomes, to reduce morbidity and complication rates 2.
• Timely diagnosis and treatment is imperative for optimal outcomes and for avoiding medicolegal ramifications 6.
• Emergent spinal surgery referral is indicated, along with urgent decompression, once cauda equina syndrome is suspected 6.
• Early intervention has been shown to portend greater chance of neurologic recovery, although improvements remain inconsistent even with expeditious surgery 6.