Cauda equina syndrome (CES) emergency decompression is an urgent operation to relieve pressure on the nerve roots at the bottom of the spinal canal. CES is one of the few true spinal surgical emergencies — delay causes irreversible bladder, bowel, and sexual dysfunction.
An emergency lumbar decompression (wide laminectomy) is performed. A midline incision is made over the lower lumbar spine. The lamina is removed at one or more levels to expose the compressed cauda equina nerve roots. The compressing pathology — usually a large central disc herniation, but occasionally a tumour, haematoma, or abscess — is removed. The nerve roots are confirmed to be decompressed. The operation takes one to two hours.
CES is diagnosed by the combination of bilateral leg pain/weakness, saddle anaesthesia (numbness around the anus, perineum, and genitals), and bladder dysfunction (urinary retention or incontinence). Any of these features in combination with back pain or sciatica is an emergency requiring MRI and urgent surgical assessment.
There are no non-operative alternatives for established CES. Delay in decompression directly worsens the prognosis for bladder and bowel recovery.
Emergency MRI confirming cauda equina compression. Urinary catheterisation to measure bladder residual volume. This is a time-critical emergency — ideally decompressed within 24–48 hours of symptom onset, though earlier is better.
Prevention or reversal of bladder, bowel, and sexual dysfunction. Relief of leg pain and weakness. The outcome depends critically on the timing of surgery — patients decompressed before complete urinary retention have significantly better outcomes than those decompressed after.
Even with prompt surgery, some patients have permanent bladder, bowel, or sexual dysfunction.
Nerve damage from the compression may not fully resolve.
Post-operative back pain is common.
The longer the compression, the higher the risk of permanent incontinence or retention. Risk is highest when complete retention has been present for more than 48 hours.
Faecal incontinence.
Erectile dysfunction, loss of genital sensation.
Risk approximately 5–10% in emergency surgery.
Wound or disc space infection.
The disc may herniate again.
General anaesthesia. Emergency. Prone positioning. May be performed at any hour.
Urinary catheter management — may take days to weeks for bladder function to recover. Physiotherapy for leg weakness. Pelvic floor rehabilitation. Sexual health support. Many patients require ongoing bladder management. Recovery continues over twelve to eighteen months — nerves recover slowly.
Bladder function assessment at two weeks, six weeks, three months, and six months. Neurological monitoring. Urology referral if bladder dysfunction persists. Pelvic floor physiotherapy.
The cauda equina nerves control the bladder, bowel, and sexual function. Once damaged by prolonged compression, these functions may never recover. Every hour of delay worsens the prognosis. Patients with suspected CES should attend A&E immediately.
Recovery depends on timing. Patients decompressed before complete urinary retention have a much better prognosis than those decompressed after. Some degree of permanent bladder dysfunction is common in CES, but many patients achieve significant recovery with time.
Any patient with back pain or sciatica who develops difficulty passing urine, loss of bladder or bowel control, or numbness in the saddle area (around the anus, perineum, or genitals) should attend A&E immediately — do not wait for a GP or outpatient appointment.