Cauda Equina Syndrome
1. Introduction
The cauda equina consists of 20 nerve roots that originate at the base of the spinal cord. The cauda equina is responsible for sensory and motor innervation to the pelvis and lower limbs, as well as bowel and bladder function. If the cauda equina is damaged by inflammation or compression in the lower back, symptoms may be severe and may develop quickly. Early medical attention and treatment are crucial for making as full a recovery as possible (2).
Cauda equina syndrome is a medical emergency and requires immediate referral for investigation (typically an MRI scan) (7). Therefore, whilst extremely rare, it is important that patients and medical professionals identify the possible symptoms suggestive of cauda equina syndrome and take appropriate action.
Frequently Asked Questions
- The cauda equina is the bundle of nerves at the base of the spine (given its name because it looks like a horse’s tail).
- Cauda equina syndrome occurs as a result of compression of these nerves, normally by one of the discs at the base of the spine.
- It is an extremely rare, yet potentially serious, medical condition (1).
- The incidence of cauda equina syndrome in the UK has been estimated to be 0.3% of people with back pain (2, 9).
- Yes.
- Although cauda equina syndrome is extremely rare, it can have life changing consequences if not acted upon in a timely manner.
- If surgical intervention is delayed, irreversible damage can occur to the bladder, bowel and sexual function (2).
- If you believe that you have the symptoms listed below then you should contact your GP or call 111 immediately.
- People with a history of back pain, particularly those who have a herniated disk.
- Previous or recent back surgery.
- People who are overweight or obese.
- A job that requires a lot of heavy lifting, twisting, pushing, and bending sideways.
- Bilateral sciatica – shooting pain running down the back of both legs.
- Reduced perineal sensation – sensation loss in the genitals and back passage.
- Altered bladder function – increased frequency, incontinence or unable to fully empty the bladder.
- Loss of anal tone – incontinence.
- Loss of sexual function – such as difficulties gaining or sustaining an erection or a loss of sensation in the vagina.
- Again, if you believe that you have the symptoms listed then you should contact your GP or call 111 immediately.
- If a medical professional considers it a possibility that you have the symptoms, you will be given a scan of the lower back to investigate further.
- If the condition is confirmed, you will require surgery to reduce the pressure on the nerves.
- The outcome following surgery is variable and depends on a number of factors, but particularly how the nerve is decompressed and the degree of nerve damage at the time of surgery (3).
- Surgery will in most cases reduce the symptoms although some people may still experience back pain, leg pain and bladder issues.
We recommend consulting a musculoskeletal physiotherapist to ensure exercises are best suited to your recovery. If you are carrying out an exercise regime without consulting a healthcare professional, you do so at your own risk.
2. Signs and Symptoms
Clinical diagnosis of cauda equina syndrome is not easy (6). Most cases are of sudden onset and progress rapidly within hours or days. However, cauda equina syndrome can evolve slowly and patients do not always complain of pain. The most commonly reported symptoms of cauda equina syndrome include:
- Numbness, pins and needles or tingling between your upper thighs, or around your genitals or bottom. This is sometimes called ‘saddle anaesthesia’. You may notice this when wiping after going to the toilet (in a study, 76% of cauda equina syndrome patients were found to have ‘saddle anaesthesia’) (3).
- New or increased difficulty in emptying a full bladder or in controlling your urine, such as leaking or incontinence or a need to use pads.
- Loss of, or reduced feeling, when urinating or not being able to tell when your bladder is full.
- Loss of bowel control or leaking, or loss of feeling in your back passage during bowel movements (75 patients of 173 tested had decreased anal tone) (4).
- New or increased difficulty with sexual functions, such as achieving/maintaining an erection, reaching orgasm or loss of feeling in your genitals during sex.
3. Causes
- Herniation of a lumbar disc – the most common cause of cauda equina syndrome is compression arising from a large central lumbar disc herniation (prolapsed/slipped disc) at the two lowest levels of the spine (6).
- Spinal conditions – late-stage ankylosing spondylitis, spondylolisthesis, spinal stenosis.
- Infections of the spinal canal (osteomyelitis) – such as a spinal epidural abscess, which in turn may potentially press into the spinal canal, producing neurological symptoms.
- Post-operative complications from lumbar surgery – a small number of patients experience cauda equina syndrome following surgery to repair a lumbar herniated disc.
- Tumours/neoplasms – tumours may originate in the spine, but it is more likely that cancer from another part of the body spreads toward the spine (malignancy) (5).
4. Risk Factors
This is not an exhaustive list. These factors could increase the likelihood of someone developing cauda equina syndrome. It does not mean everyone with these risk factors will develop symptoms.
A wide range of pre-existing conditions may lead to the development of cauda equina syndrome including the following:
- Spinal stenosis, causing a narrowing of the spinal canal which houses the cauda equina nerves.
- A herniated disc, which might lead to pressure on, and distortion of, the spinal canal causing compression of the cauda equina nerves.
- Inflammation of the spine due, for example, to ankylosing spondylitis.
General health or life risk factors which might make someone susceptible to the development of cauda equina syndrome include:
- Being over the age of 30.
- Being overweight.
- Undertaking regular work that might put considerable strain on the spine.
5. Prevalence
Cauda equina syndrome is an extremely rare condition. It is reported in approximately 0.04% of all patients presenting with low back pain. Cauda equina syndrome occurs in approximately 2% of cases of herniated lumbar discs (2,9).
6. Assessment & Diagnosis
The diagnosis of cauda equina syndrome is primarily based on a thorough history and clinical examination, assisted by appropriate radiological investigation (7). The only way to exclude the diagnosis of cauda equina syndrome is with an emergency MRI scan. About 40% of requested scans show no evidence of cauda equina compression (1).
Cauda equina syndrome is often categorised as a progressive problem with worsening back pain, sometimes affecting one leg and then the other. There are various, less-alarming reasons for some of the above symptoms, therefore a thorough assessment is necessary to establish the likely cause.
The following is what constitutes an objective exam to assess for cauda equina syndrome. Your physiotherapist will assess your sensation, muscle power, reflexes and will also perform upper and lower neuron testing.
7. Self-Management
Cauda equina syndrome is not a condition that can be managed by yourself as it requires urgent medical attention. As already mentioned, the important thing is that if you suspect you have the symptoms of the condition you contact your GP or call 111 immediately.
8. Rehabilitation
Post-operative care includes addressing lifestyle issues, e.g. obesity, and physiotherapy/occupational therapy, depending on residual lower limb dysfunction. While it is generally thought that neurological damage caused by cauda equina syndrome is permanent, some studies have reported that long-term management may allow patients further improvement following surgery to eventually regain a near-normal voiding of a bladder with little daily interruption (10). Management of this condition should be carried out on a case by case basis and you will require specialist physiotherapy to maximise your recovery.
9. Cauda Equina Syndrome
Rehabilitation Plans
Our team of expert musculoskeletal physiotherapist have created rehabilitation plans to enable people to manage their condition. If you have any questions or concerns about a condition, we recommend you book an consultation with one of our clinicians.
Due to the severity of cauda equina syndrome, please go to A&E as soon as possible if you suspect you have symptoms that suggest this condition.
10. Return to Sport / Normal life
The ability to return to sporting activities and activities of daily life will be dependent on the success of the surgery. However, in all cases working alongside your physiotherapist on a comprehensive rehabilitation programme will provide you the best outcome possible (10).
11. Other Treatment Options
Patients should be referred immediately for a neurosurgical consultation if diagnosed with cauda equina syndrome. Urgent surgical spinal decompression is indicated for most patients to prevent permanent neurological damage (7). Following surgery, the extent of recovery is variable. Patients may continue to experience some low back or leg pain, bladder or bowel dysfunction, and other physical problems depending on the duration of nerve compression and the severity of symptoms at the time of surgery. The data suggests that the severity of bladder dysfunction at the time of surgery is the dominant factor in recovery of bladder function (10).
References
- Fairbank, J., & Mallen, C. (2014). Cauda equina syndrome: Implications for primary care. The British Journal of General Practice. 64, 67–68. https://doi.org/10.3399/bjgp14X676988.
- Finucane, L. M., Downie, A., Mercer, C., Greenhalgh, S. M., Boissonnault, W. G., Pool-Goudzwaard, A. L., Beneciuk, J. M., Leech, R. L., & Selfe, J. (2020). International Framework for Red Flags for Potential Serious Spinal Pathologies. Journal of Orthopaedic & Sports.
- Gitelman, A., Hishmeh, S., Morelli, B. N., Joseph Jr, S. A., Casden, A., Kuflik, P., Neuwirth, M., & Stephen, M. Cauda equina syndrome: A comprehensive review. American Journal of Orthopedics (Belle Mead, N.J.), 37, 556-62.
- Gooding, B. W., Higgins, M. A., & Calthorpe, D. A. Does rectal examination have any value in the clinical diagnosis of cauda equina syndrome? British Journal of Neurosurgery, 27, 156–159.
- Kostuik, J. P. (2004). Medicolegal consequences of cauda equina syndrome: An overview. Neurosurgical Focus, 27, 156–159.
- Lavy, C., James, A., Wilson-MacDonald, J., & Fairbank, J. (2009). Cauda equina syndrome. BMJ (Clinical Research Ed.), 338, b936. https://doi.org/10.1136/bmj.b936
- Ma, B., Wu, H., Jia, L., Yuan, W., Shi, G., & Shi, J. (2009). Cauda equina syndrome: A review of clinical progress. Chinese Medical Journal, 122, 1214–1222.
- Mtui, E., Gruener, G., & Dockery, P. (2015). Fitzgerald’s Clinical Neuroanatomy and Neuroscience E-Book. Elsevier Health Sciences.
- Mukherjee, S., Thakur, B., & Crocker, M. (2013). Cauda equina syndrome: A clinical review for the frontline clinician. British Journal of Hospital Medicine. 74, 460–464. https://doi.org/10.12968/hmed.2013.74.8.460.
- Qureshi, A., & Sell, P. (2007). Cauda equina syndrome treated by surgical decompression: The influence of timing on surgical outcome. European Spine Journal, 16, 2143-2151. https://doi.org/10.1007/s00586-007-0491-y.
Other Conditions in
Lower Back, Neurological, Orthopaedics
Spondylolysis
An injury due to a stress fracture through part of a vertebra known as the pars interarticularis of the lumbar vertebrae (lower back).
Spondylolisthesis
A term to describe a slight change in position (usually further forward) of one vertebra relative to the vertebrae below.
Sacroiliac Joint Dysfunction
Pain originating from the sacroiliac joint at the base of your back where the spine joins the pelvis.
Mechanical Back Pain
Lower back pain caused by structures in the back, such as joints, bones and soft tissues.
Lumbar Spinal Stenosis
Narrowing of the spaces though which lower back spinal nerves travel which can result in weakness, pain and reduced function.
Lumbar Disc Injury
Lumbar discs sit between each of the bones of the spine. Problems can occur when these discs become irritated.
Low Back Pain and Sciatica
Sciatica is a symptom describing pain and/or pins and needles down the back of the leg.
Greater Trochanteric Pain Syndrome
A condition affecting the tendons that insert into outside of the hip. A common cause of pain felt around the hip and pelvis.
Femoroacetabular Impingement
A condition that results in pain in the groin, hip and down the front of the thigh.
Femoral Nerve Radiculopathy
This is where the nerve that supplies the front of the leg is irritated and causes pain/numbess.
Deep Gluteal/Piriformis Syndrome
A presentation where the sciatic nerve is irritated in the buttock and can cause sciatica symptoms in the leg.
Benign Joint Hypermobility Syndrome
Common age related changes to the structure of the knee joint which may be associated with pain, stiffness and loss of function.
Ankylosing Spondylitis
A rare condition that can cause joint stiffness and pain, often worse at night and when resting.