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Cauda equina syndrome

Cauda Equina Syndrome: A Spine Emergency You Need to Recognize

THIS IS A MEDICAL EMERGENCY

If you have new numbness in your groin or inner thighs, trouble urinating or controlling your bladder or bowels, or weakness in both legs, call 911 or go to the nearest emergency room now. Cauda equina syndrome needs emergency treatment.

Rarity
Rare, but serious
Key warning sign
Saddle numbness
Most common cause
Large disc herniation
Best results
Fast surgery

What Is Cauda Equina Syndrome?

At the bottom of the spinal canal, the spinal cord ends and continues as a bundle of nerve roots that looks like a horse’s tail, which is what “cauda equina” means in Latin. These nerves control your legs, bladder, bowels and sexual function, and carry feeling from the groin and buttocks.

Cauda equina syndrome happens when something suddenly squeezes these nerves. It is rare, but it is a true surgical emergency. Fast diagnosis and surgery to relieve the pressure give the best chance of preserving bladder, bowel, sexual and leg function.

Sagittal MRI of the lumbar spine showing a large disc herniation pressing on the nerves of the cauda equina
Lumbar spine MRI (side view) showing a large disc herniation compressing the nerves of the cauda equina.

What’s Happening in Your Spine

The nerves of the cauda equina share a tight space in the lower spinal canal. When that space is suddenly filled, all of the nerves are compressed at once. The most common causes are:

Large herniated disc
A large herniated disc in the lower back is the most common cause.
Severe spinal stenosis
Severe spinal stenosis can narrow the canal until the nerves are squeezed.
Tumors
Tumors in or near the spinal canal can press on the nerves.
Infection
An infection such as an epidural abscess can fill the canal.
Bleeding
A blood collection (hematoma), including after spine surgery or injury.
Trauma
Fractures or other injuries that narrow the spinal canal.

Warning Signs

Red-flag symptoms: go to the emergency room

  • Numbness in the “saddle” area: groin, genitals, buttocks or inner thighs
  • Trouble starting urination, a weak stream, or not feeling when your bladder is full
  • Leaking urine or losing control of your bowels
  • New sexual dysfunction or loss of sensation
  • Weakness or numbness in both legs, or rapidly worsening weakness
Chart of red-flag symptoms of cauda equina syndrome
Image: Claire Cesa, CC BY-SA 4.0 (source)

Symptoms that often come first

  • Severe low back pain
  • Sciatica in one or both legs

Not everyone with severe sciatica has cauda equina syndrome. But anyone with back or leg pain who develops any of the red-flag symptoms above should be seen in an emergency room right away, not at a routine office visit.

If You Think You Have It: What to Do

1
Go to the emergency room now
Call 911 or have someone drive you. Don’t wait for an office appointment or to see if symptoms improve.
2
Say the words “cauda equina syndrome”
Tell the triage team your symptoms and that you are worried about cauda equina syndrome. Mention any recent back surgery or injury.
3
Expect a quick exam and an urgent MRI
The team will check sensation and strength, scan your bladder, and order an emergency MRI of the lower spine.
4
Surgery to relieve the pressure
If the MRI confirms compression, a spine surgeon decompresses the nerves as quickly as possible.

How Cauda Equina Syndrome Is Diagnosed

Urgent neurological exam
Checks sensation in the saddle area, leg strength and reflexes.
Bladder scan
Measures how much urine stays in your bladder after you try to empty it.
Emergency MRI
Confirms the diagnosis and shows exactly what is compressing the nerves.
An option if MRI isn’t possible.

Treatment

Cauda equina syndrome is treated with urgent surgery to remove whatever is compressing the nerves. Research shows that outcomes are best when decompression happens quickly, ideally within the first 24 to 48 hours of symptoms. Depending on the cause, surgery may include:

Removing a large disc herniation.
Opening the spinal canal to relieve pressure.
Tumor, abscess or blood removal
Removing the problem, along with treatment of the underlying cause.
Stabilization
Added if the spine is unstable.

Recovery

Hospital stay
Usually a few days, with monitoring of bladder function.
First weeks
Walking and gradual activity; some patients need a catheter for a period of time.
Months 1-12
Leg strength, sensation, bladder, bowel and sexual function can continue to improve for a year or longer.
Rehabilitation
Physical therapy, and sometimes pelvic floor therapy or urology follow-up.

Recovery depends a great deal on how severe the compression was and how quickly it was treated. Some patients recover fully, while others have lasting effects.

Frequently Asked Questions

How fast do I need to get to the hospital?
Immediately. If you have red-flag symptoms, go to the emergency room now. Don’t wait for an office appointment or to see if symptoms improve.
I have bad sciatica. Do I have cauda equina syndrome?
Probably not. Most sciatica is not cauda equina syndrome. The warning signs to watch for are saddle numbness, bladder or bowel changes, sexual dysfunction, or weakness in both legs.
Will my bladder function come back?
Many patients improve after surgery, especially when surgery happens early and before complete loss of bladder control. Recovery can take months.
Can cauda equina syndrome happen after spine surgery?
Rarely, bleeding or swelling after surgery can compress the nerves. Any new saddle numbness, bladder changes or leg weakness after surgery should be reported immediately.
What should I do if I’m not sure?
Go to the emergency room and tell them you are worried about cauda equina syndrome. It’s always better to be checked.

Follow-Up Care with Southern Neurosurgery

For red-flag symptoms, call 911 or go to the nearest emergency room. Do not wait for an appointment.

For follow-up care, a second opinion, or questions about back and leg symptoms that are not an emergency, call 470-293-9800 or contact us online. Have a non-urgent question? Ask our virtual assistant, 24/7.

We see patients across metro Atlanta and North Georgia at our offices in:

GainesvilleSandy SpringsSouth Atlanta (Riverdale)

Find the office nearest you.

This page is for educational purposes only and is not a substitute for medical advice. If you have sudden weakness, numbness in the groin, or bladder or bowel changes, call 911 or go to the nearest emergency room.