Understanding Cauda Equina Syndrome: A Guide

Cauda equina syndrome (CES) is a neurological condition characterised by a sudden loss of function of the lumbar plexus – the nerve roots of the spinal canal in the spinal cord – usually due to compression, trauma or other damage to the area.

The spinal canal contains a mass of nerves (the cauda equina which means ‘horse tail’) that branches off at the lower end of the spinal cord and houses the nerve roots from L1-5 and S1-5.¹

The nerve roots from L4-S4 connect in the sacral plexus, affecting the sciatic nerve as it heads to the feet.

Causes of cauda equina syndrome

Cauda equina syndrome can be caused by a slipped disc, fractures, wounds (knife, bullets), or tumours or other lesions that upset the function of the nerves.

A bad lumbar puncture, trauma created by catheters, or high doses of anaesthetics in the area can also trigger CES. Lumbar spinal stenosis can also cause CES, with the spinal canal narrowing, often due to osteoarthritis or other degenerative diseases, or in fact an anatomical abnormality.^2,3

The most severe case of CES is called spondylolisthesis cauda equina syndrome, and can result in death. Chronic spinal inflammation may be a cause, including Paget’s disease, ankylosing spondylitis, tuberculosis, or polyneuropathy.

It can also occur during pregnancy due to lumbar disc herniation, with age of the mother increasing the risk. Surgery can be performed on pregnant women.^4,5

Signs and symptoms of cauda equina syndrome

The lower extremities may become weak
Lower extremities may become paralysed
Smooth muscle of the bladder (detrusor) may become weak, causing urinary retention and post-void residual incontinence
Loss of anal tone and faecal incontinence
Sexual dysfunction
Saddle anaesthesia (numbness)
Leg pain
Leg weakness
Lack of ankle reflexes
Usually there is no pain and the person can walk

Treatment of cauda equina syndrome

Treatments usually include surgery to decompress the spine and remove problematic bone, tumours or blood, depending on the cause.

CES is considered a medical emergency, because if not treated quickly, long-term damage to nerves can occur.⁶ Steroids may be used. Physiotherapy may be required.

Outcomes of cauda equina syndrome

Typically a complete recovery is seen, but this depends on many factors.⁷ Severity and duration of nerve compression matters a lot when it comes to outcomes, so the longer time the nerve was compressed, the worse the outcome.⁸

Nerve regrowth may be impossible at certain stages of damage. Nerves take a very long time to grow, so recovery may be years.

Early detection can significantly improve outcomes, with early signs being changes in the bowel and bladder, and a loss of sensation in the groin area.⁹

References

1.
Shahmohammadi M, Khoshuod R, Zali A, Seddeghi A, Kabir N. Examination of The Predictive Power of Electromyography and Urodynamic Study in Patients with Cauda Equina Syndrome (Horse Tail Syndrome). Acta Inform Med. Published online 2016:328. doi:10.5455/aim.2016.24.328-331
2.
Choudhury AR, Taylor JC. Cauda Equina Syndrome in Lumbar Disc Disease. Acta Orthopaedica Scandinavica. Published online January 1980:493-499. doi:10.3109/17453678008990830
3.
Woodfield J, Lammy S, Jamjoom AAB, et al. Demographics of Cauda Equina Syndrome: A Population-Based Incidence Study. Neuroepidemiology. Published online 2022:460-468. doi:10.1159/000527727
4.
Hakan T. Lumbar disk herniation presented with cauda equina syndrome in a pregnant woman. Journal of Neurosciences in Rural Practice. Published online May 2012:197-199. doi:10.4103/0976-3147.98243
5.
Viseu Pinheiro JFJ, Hernández DP, Blanco JFB. Cauda equina syndrome during pregnancy: A condition to consider. International Journal of Surgery Case Reports. Published online 2018:14-16. doi:10.1016/j.ijscr.2018.05.026
6.
Heyes G, Jones M, Verzin E, McLorinan G, Darwish N, Eames N. Influence of timing of surgery on Cauda equina syndrome: Outcomes at a national spinal centre. Journal of Orthopaedics. Published online March 2018:210-215. doi:10.1016/j.jor.2018.01.020
7.
Woodfield J, Hoeritzauer I, Jamjoom AAB, et al. Presentation, management, and outcomes of cauda equina syndrome up to one year after surgery, using clinician and participant reporting: a multi-centre prospective cohort study. The Lancet Regional Health – Europe. Published online January 2023:100545. doi:10.1016/j.lanepe.2022.100545
8.
Fuso FAF, Dias ALN, Letaif OB, Cristante AF, Marcon RM, Barros Filho TEP de. Estudo epidemiológico da síndrome da cauda equina. Acta ortop bras. Published online June 2013:159-162. doi:10.1590/s1413-78522013000300006
9.
Thakur JD, Storey C, Kalakoti P, et al. Early intervention in cauda equina syndrome associated with better outcomes: a myth or reality? Insights from the Nationwide Inpatient Sample database (2005–2011). The Spine Journal. Published online October 2017:1435-1448. doi:10.1016/j.spinee.2017.04.023