Cauda Equina Syndrome (Emergency Nerve Compression in the Lower Back)

Cauda equina syndrome is a rare condition where the bundle of nerves at the bottom of your spine is suddenly squeezed. It needs same-day assessment, because early surgery gives the best chance of a full recovery. If you have new bladder or bowel problems, or numbness around your groin, go to a hospital emergency department now.

Reviewed by Dr. Kshitij Chaudhary — Last reviewed September 2026

What Is Cauda Equina Syndrome?

Your spinal cord ends in the upper part of your lower back. Below that, a bundle of nerve roots carries on down the spine. Doctors call it the cauda equina, Latin for "horse's tail". These nerves control your legs, bladder, bowel and sexual function, and give feeling to the area you sit on.

In cauda equina syndrome, something presses hard on this bundle. The nerves stop working properly, and the damage can become permanent if the pressure isn't relieved quickly.

What Causes It?

• A large disc herniation: The most common cause. See Lumbar Disc Herniation & Sciatica
• Severe narrowing of the spinal canal: See Lumbar Spinal Stenosis
• Less common causes: Tumours, infection, fractures, or bleeding around the spine, sometimes linked to blood thinners

Who Gets It?

It is rare. Most cases come from a large disc herniation in working-age adults.

How Serious Is It?

It is serious, but treatable. Having sciatica does not mean you are heading towards cauda equina syndrome. The vast majority of slipped discs never cause it.

What matters is spotting it early. The sooner the nerves are freed, the better they recover.

What Are the Warning Signs?

• Difficulty passing urine, or losing control of your bladder
• Losing control of your bowel
• Numbness around the groin, inner thighs or buttocks, the area you would sit on a saddle
• New problems with sexual function
• Weakness in one or both legs that is getting worse quickly
• Severe back pain with leg pain in one or both legs

You don't need every sign. New numbness around the groin and new bladder problems are the two to act on straight away.

How Is It Diagnosed?

• Examination: Your doctor checks the feeling around your groin and back passage, your leg strength, reflexes and bladder
• Urgent MRI: This confirms the diagnosis and shows what is pressing on the nerves
• Bladder scan: An ultrasound checks how well your bladder is emptying

Will It Get Worse?

It can, often over hours to a few days. Some cases come on more slowly. That is why any new bladder or groin symptoms need checking the same day, however they started.

Can It Be Treated Without Surgery?

No. Once cauda equina syndrome is confirmed, surgery is the treatment. Rest, medicines or physiotherapy will not relieve the pressure.

When Is Surgery Needed?

As soon as possible after the diagnosis is confirmed. The earlier the pressure is relieved, the better the chance of the nerves recovering.

What Does Surgery Involve?

Your surgeon removes whatever is pressing on the nerves. Most often this is a microdiscectomy to take out a large disc herniation. If the canal is narrow, your surgeon may also remove bone and ligament (decompression). The exact operation depends on the cause.

How Long Is Recovery?

Leg pain and leg weakness often improve fairly quickly after surgery. Bladder, bowel and sexual function recover more slowly, sometimes over months.

Many people recover fully, especially when treated early. Some are left with lasting changes, particularly if treatment was delayed.

Can I Prevent It?

Not entirely. If you have sciatica or a known disc herniation, learn the warning signs above. Acting fast is the best protection.

What Questions Should I Ask My Doctor?

• What is pressing on the nerves?
• How soon should surgery be done?
• What recovery can I expect for my bladder, bowel and legs?
• Will I need a catheter or bladder follow-up after surgery?
• What should I watch for once I'm home?

Treatments We Offer for This

• Microdiscectomy (Slipped Disc Surgery)
• Laminectomy (Lumbar Decompression)

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About Dr. Kshitij Chaudhary

This page was written by Dr. Kshitij Chaudhary, a fellowship-trained spine surgeon at P.D. Hinduja Hospital, Mumbai, trained in complex spine surgery at Harvard Medical School (Beth Israel Deaconess) and the Twin Cities Spine Center, Minneapolis. 🏃🏾About Dr. Chaudhary

This information is for general education and does not replace a consultation with your doctor.