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Key points
- Cauda equina syndrome (CES) happens when the bundle of nerves at the bottom of the spinal canal is squashed, most often by a large disc prolapse. It is an emergency.
- Back pain or sciatica together with new numbness around your bottom or genitals, or a change in bladder, bowel or sexual function, needs same-day emergency assessment.
- The national NHS pathway says an emergency MRI should happen as soon as possible, and no later than four hours after it is requested.
- Surgery aims to protect the nerve function you still have. It cannot reverse damage that has already happened, and recovery can continue for up to two years.
- Bladder recovery varies. Long-term studies suggest about a third of people have some ongoing bladder problems, and those who had lost bladder control before surgery tend to recover less.
Seek urgent medical help (A&E or 999) if you have back pain or sciatica with any of these:
- Numbness or altered feeling around your back passage, genitals or inner thighs (the saddle area)
- Difficulty starting to pass urine, or not being able to feel the flow
- Loss of control of your bladder or bowels that is new for you
- Not being able to feel when your bowel is full
- New problems getting an erection or ejaculating, or loss of genital sensation
- Severe or worsening weakness in both legs
What is cauda equina syndrome?
Below the end of the spinal cord, the nerves to the legs, bladder, bowel and genitals run down the spinal canal in a bundle that looks like a horse’s tail, the cauda equina. These nerves also carry feeling from the skin of the buttocks and around the anus.[1] If they are compressed suddenly, the result is cauda equina syndrome.
The commonest cause is a large disc prolapse pushing straight back into the middle of the canal. Other causes include a smaller bulge on top of existing narrowing (stenosis), tumours, infection, bleeding and serious injury.[2] CES is rare, affecting about 1 to 3 in every 100,000 people.[3] You can read more about the condition in our guide to cauda equina syndrome.
From A&E to the operating theatre
In England, care follows the National Suspected Cauda Equina Syndrome Pathway, produced by NHS England’s Getting It Right First Time (GIRFT) programme and backed by BASS.[3]
1. Assessment
A doctor will examine your leg strength, reflexes and feeling, including around the bottom and genitals, and may check the back passage.[2] You may have a bladder scan to see how much urine is left after you pass water. GIRFT stresses that this scan helps but is never used on its own to decide whether you need an MRI. If your bladder is holding a large amount, a catheter will be passed to drain it.[3]
Pain alone can make it harder to pass urine, so good pain relief early on helps both your comfort and the assessment.[1]
2. Emergency MRI
An MRI scan is the key test. The pathway says it should happen as soon as possible and no later than four hours after it is requested. You will be kept nil by mouth in case you need surgery. If your hospital cannot scan or operate, you may be transferred by blue-light ambulance. No single symptom or scan proves CES: the diagnosis rests on your symptoms, examination and MRI together. If the scan shows a different cause, such as a disc pressing on one nerve, you should be given clear advice about warning signs and onward care.[3]
3. Deciding on surgery
If the MRI confirms compression, the spinal team will see you straight away, explain the findings and ask for your consent. For people who still have some bladder control, GIRFT says surgery should happen as quickly as possible as an emergency. For people who already have painless retention of urine, surgery should still take place within 24 hours of the scan, and around 70% of these patients still benefit from decompression.[3] Operations due to start between midnight and 07:30 need the on-call consultant’s agreement, so a short wait overnight can be a deliberate safety decision. If you take blood thinners, you may be given medicine to reverse them.[2]
4. The operation
Under general anaesthetic, the surgeon makes a cut in the middle of the lower back and removes some bone from the roof of the spinal canal, either the whole lamina (laminectomy) or a smaller window (laminotomy). This gives room to remove the disc fragment and free the nerves, often using a microscope.[2] A catheter is placed before surgery begins.[3]
Why timing matters
BASS states that outcomes appear better when decompression happens within 48 hours of symptoms starting, and that most surgeons prefer to operate as soon as it is safe.[1] A 2026 meta-analysis by Najjar and colleagues, covering 15 studies and 26,627 adults, found that surgery within 48 hours of symptom onset was linked to better early bladder and leg recovery, especially in people who still had some bladder control. Operating within 24 hours was not consistently better than at 24 to 48 hours, and by a year or more, bladder function before surgery mattered more than timing.[4] An earlier review by Chau and colleagues argued there is no strong basis for treating 48 hours as a safe window, and that earlier surgery is probably better for acutely compressed nerves.[5] The message is simple: seek help the moment symptoms appear.
After surgery
You will wake in the recovery area with a drip, and sometimes a wound drain that usually comes out the next day.[2] Most people get up on the first day after surgery.[3] Some people notice leg pain easing straight away, but it can take 8 to 12 weeks or longer to settle. Numbness and tingling may take 18 months to 2 years to improve.[2]
Bladder recovery
Bladder problems often remain straight after surgery. The pathway recommends a trial without catheter as soon as possible, with bladder scans before and after you pass urine. If very little is left behind (under 100ml), you can go home without a catheter. If not, a longer-term catheter with a valve is fitted, and you will be taught intermittent self-catheterisation where possible, with follow-up from a spinal cord injury or urology service.[3] Self-catheterisation usually means passing a thin tube 3 to 4 times a day to empty the bladder.[2]
Bladder and bowel control can keep improving for up to two years.[2] A 2026 review of 16 studies and 987 patients found ongoing bladder problems in about a third of people at a year or more, with worse outcomes in those who had urinary retention before surgery.[6]
Bowel, sexual function and wellbeing
You may be prescribed laxatives and taught a bowel routine. Sexual difficulties can occur and should be checked at follow-up. People with lasting symptoms should be put in touch with their regional spinal cord injury service, and offered psychological support and contact with groups such as the Cauda Equina Champions Charity and the Spinal Injuries Association.[3]
Going home
- Shower after 48 hours, keeping the dressing dry, and avoid baths for two weeks. Removable stitches or clips usually come out at 10 to 14 days.[2]
- Avoid heavy lifting for at least 2 to 3 weeks, possibly up to three months.[2]
- Most people can drive at 4 to 6 weeks if they can do an emergency stop. BASS also advises informing the DVLA.[2]
- After a full recovery, people typically return to work at about four weeks, or up to eight for a physical job.[2]
Risks and complications
GIRFT notes that complications are about six times more common after emergency surgery for CES than after routine decompression.[3] The figures below are from BASS.[2]
| Risk | Approximate frequency (BASS) |
|---|---|
| Tear in the lining around the nerves (dural tear) | 5 to 15 in 100 (up to 25 in 100 in repeat surgery) |
| Recurrent or worsening leg pain | More than 5 in 100 |
| Superficial wound infection | Up to 4 in 100 |
| Nerve root damage | Fewer than 1 in 100 (up to 10 in 100 in repeat surgery) |
| Deep wound infection | Fewer than 1 in 100 |
| Blood clot in the leg or lung | Fewer than 1 in 700 |
| Further surgery for a persistent fluid leak | Fewer than 5 in 10,000 |
| Injury to a major blood vessel | 1 in 4,000 |
| Death from damage to major blood vessels or organs | 1 in 10,000 |
| Fatal anaesthetic complication | 1 in 250,000 |
Very rarely, bleeding into the spinal canal or reduced blood supply can cause further nerve damage, including paralysis.[2]
When to seek help after surgery
Go to A&E straight away if your numbness, bladder or bowel control, or leg strength gets worse. Contact the hospital or your GP if your wound becomes red or leaks, if you develop a high temperature, or if you get repeated urine infections or feel your bladder is not emptying.[2]
Further reading
References
- British Association of Spine Surgeons. Cauda equina syndrome (patient information web page). BASS. Link
- British Association of Spine Surgeons. Cauda equina syndrome: surgical options (patient booklet, issue 2). BASS; 2022. Link
- Getting It Right First Time, NHS England. Spinal surgery: National Suspected Cauda Equina Syndrome (CES) Pathway. February 2023, updated March 2026. Link
- Najjar E, et al. Reassessing the clock in cauda equina syndrome: a systematic review and meta-analysis of surgical timing and outcomes. Spine J. 2026;26(9):1653-70. Link
- Chau AM, et al. Timing of surgical intervention in cauda equina syndrome: a systematic critical review. World Neurosurg. 2014;81(3-4):640-50. Link
- Najjar E, et al. Reassessing bladder recovery in cauda equina syndrome: long-term outcomes after surgical decompression: a systematic review and meta-analysis. Spine J. 2026; online ahead of print. Link
This guide is general information and is not a substitute for advice about your own situation. Please discuss the benefits and risks of any procedure with your surgeon.
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