Cauda Equina Syndrome: revisited

A recent study done in a hospital in Scotland highlighted some observations we have noticed in clinical practice. Namely that many patients who present with the physical symptoms of Cauda Equina Syndrome do not have cauda equina compression, but a different problem.

They assessed 198 patients that presented with cauda equina symptoms and signs, including urinary retention, and found:

• 1/3 had genuine cauda equina compression as demonstrated by MRI.
• 1/3 had a mixed picture – some spine disease, such as disc protrusion but not actual compression.

These patients may have sciatica or a painful disc herniation, but the urinary retention is atypical. The latter could well have a pharmacological cause such as opioid analgesics or gabapentinoid medication.

• 1/3 displayed the classic symptoms, including urinary retention, but a scan of the spine revealed there was no compression.

The people in this latter group had developed a functional neurological disorder, were in discomfort and so needed help. It is just that their problem was not caused by cauda equina compression.  These people tend to higher rates of mental health disorders.

The best support for them is a blend of physio and psychological support, available through specialist clinics. Some neurology departments run functional disorders clinics, or a pain clinic would also offer help. The starting point is to refer them.

So, it is accepted that the usual rate of ‘positive’ MRI scans for potential cauda equina syndrome is about 30%.

Nonetheless true cauda equina syndrome is a serious condition and unfortunately it can be missed.

As a result, for an uncommon condition, cauda equina syndrome is over-represented in medico-legal actions.

If your patients are displaying any of the classic symptoms:

• urinary retention – the primary indicator
• numbness in the buttocks 
• neurological deficit in the lower limbs
• back pain

then it is important to act immediately and arrange an urgent MRI, or send them straight to the emergency department of your nearest hospital.

It is just worth highlighting to them before they go that two-thirds of those who display the symptoms do not have cauda equina compression, and may need a different kind of specialist care. This can be identified after the MRI scan and diagnosis.

Diagnosis

If the symptoms are blurred and you want to do an in-clinic diagnosis, then a post void residual urine test can help to narrow that down.

If they have more than 200ml then they are in the high-risk category and should be investigated urgently.

If you have any questions about your patient’s diagnosis, feel free to call me on 02 9650 4893 for an opinion. You can also reach me via ralphstanford@powspine.com.au.

Webinar – Cauda Equina Revisited

I held an educative webinar on 7 August 2024, as a refresher to bring GPs up to date on the latest research about the condition. 

Click here to watch the replay >>

Dr Ralph Stanford is a spinal surgeon with over 20 years’ experience. He is adept in all surgical approaches to successfully treat his patients.

Dr Stanford is Head of the Department of Orthopaedics at Prince of Wales Hospital. As a teacher, he is Conjoint Senior Lecturer at the University of New South Wales; Supervisor of Training for Orthopaedic Trainees, Prince of Wales Hospital; and has previously been Education Secretary for the Spine Society of Australia.

As a researcher and scientist, Dr Stanford is a well-published author and Honorary Senior Scientist at Neuroscience Research Australia (NeuRA). He is also a current member of Spinal PFET.

Further Resources for GPs include:

• Cauda Equina: the dangerous misconception
• Foot Drop
• The limited role of cortisone injections for spinal conditions
• Cervical myelopathy – a disease of the spinal cord that may pass unnoticed
• Back pain and how to manage it

Posted 18 July 2024