Cauda equina syndrome can be caused by a large disc prolapse in the spine at the L4/5 level.
Large L4/5 disc prolapse
A disc prolapse is also called a slipped disc or disc herniation. It happens when the inside of a vertebral disc bulges through a weakness in the exterior wall. This may not cause any problems, but for some the bulging disc will press upon surrounding structures, most notably the nerves.
Disc prolapses vary in size. If there is a large disc prolapse in the L4/5 segment of the spine, it is possible that the disc will compress the cauda equina nerves which sit nearby. The L4/5 segment of the spine is in the lower back in the lumbar region.
Cauda equina syndrome from L4/5 disc prolapse
If there is a large L4/5 disc prolapse which compresses the cauda equina nerves, the nerves will quickly become damaged. Once injured the nerves will not function properly and the patient will start to experience neurological dysfunction including:
- Back pain
- Loss of sensation in the genitals, perineum and buttocks
- Reduced power in the lower limbs
- Reduced anal tone
- Urinary symptoms such as poor flow and reduced sensation
When someone develops these symptoms because of cauda equina compression, he/she should be diagnosed with cauda equina syndrome. Anyone suspected of having cauda equina syndrome must have an emergency MRI scan – firstly to confirm a diagnosis, and secondly to determine the cause of compression.
MRI scan for disc prolapse
If there is indeed a slipped disc, the MRI scan will reveal a large extruded disc prolapse at L4/5, perhaps also with caudal migration. This will be compressing the cauda equina, resulting in a loss of function which in turn causes the patient to experience symptoms.
Along with the extruded disc prolapse, the MRI scan may show concurrent abnormalities, including a narrowing of the spinal canal by ligamentum flavum, facet hypertrophy, compression of exiting nerve roots, signs of degeneration and disc bulge at L3/4.
Once a diagnosis can be verified and the large disc prolapse identified, emergency surgery should be arranged. This is the only way to successfully treat cauda equina syndrome. There is only a small window of opportunity before the nerves become permanently harmed, so immediate action is required.
Delayed diagnosis and treatment of cauda equina syndrome
If there is a delay in the diagnosis and treatment of cauda equina syndrome from a large prolapsed disc, there may be a case of medical negligence. If this has happened to you, please get in touch with us today.