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Cauda Equina Syndrome

Cauda Equina Syndrome

Cauda equina syndrome must be properly managed by medical practitioners or a patient could face long-term complications. If the standard of care falls below what is considered reasonable, and this causes a patient undue suffering, there will be grounds for a medical negligence compensation claim.

What is cauda equina syndrome?

Cauda equina syndrome (CES) refers to the compression of the lumbosacral nerve roots, located at the end of the spinal cord. These nerves are called the cauda equina nerves.

'Cauda equina' is Latin for horse's tail, and the nerves are so called because early anatomists believed that is what they looked like. Together the nerves provide motor and sensory function to the lower limbs, pelvic and sexual organs (including the bladder and bowel), and to the perineum.

When the nerves are compressed they will become damaged. Subsequently motor and sensory function will begin to diminish. When neurological problems arise due to cauda equina compression, a person is said to have cauda equina syndrome.

Causes of cauda equina compression

The cauda equina nerves can be compressed in a number of ways, including (but not limited to):-

  • Prolapsed (slipped/herniated) disc
  • Space occupying lesion such as a spinal tumour or abscess
  • Fracture of the spine
  • Traumatic accident
  • Infection
  • Inflammatory disease such as ankylosing spondylitis

Of all of these, a central prolapsed disc is the most common cause of cauda equina compression.

Prolapsed disc and cauda equina syndrome

A prolapsed lumbar intervertebral disc usually causes unilateral nerve root irritation. This will lead to the clinical features of sciatica in one leg, accompanying muscle weakness, an area of altered sensation (such as pins and needles) or numbness. The may also be reflex alteration. This clinical syndrome is by far and away the most frequent.

In less than 5% of cases, a lumbar intervertebral disc will prolapse centrally. When there is a large central disc prolapse, it will lead to cauda equina syndrome.

Cauda equina syndrome arises as a result of a central or centrolateral disc prolapse. The distinguishing features are bilateral sciatica (i.e. sciatica in both legs), a sensory disturbance in the saddle area, numbness or pins and needles, low back pain and motor weakness of the lower extremities. There will also be bowel and bladder dysfunction, sexual dysfunction, erectile dysfunction or altered sexual sensation, particularly lack of sensation.

Symptoms of cauda equina syndrome

Whatever the underlying cause of compression, the effect will be the same. The blood supply to the nerves will be restricted, leaving the nerves deficient in oxygen. This will damage the nerves, resulting in loss of function. This loss of function will become gradually worse with time, until eventually there is complete neurological dysfunction.

When the cauda equina nerves are injured, it will lead to the following symptoms:-

  • Severe lower back pain
  • Sciatic pain in one or both legs
  • Perineal numbness
  • Weakness and numbness in the legs and buttocks
  • Difficulty with urinary function (see below)
  • Difficulty with bowel function

Difficulty with urinary function is perhaps one of the most obvious symptoms of cauda equina compression, as humans tend to empty their bladder on a frequent basis. The urinary symptoms associated with cauda equina syndrome include:-

  • Altered urethral sensation
  • Loss of desire to void
  • Hesitancy and poor urinary flow
  • Loss of sensation of bladder fullness
  • Feeling of retention or incomplete voiding
  • Need to strain to void
  • Perirectal numbness
  • Loss of rectal control
  • Sensory abnormalities in the rectum/anal canal e.g. inability to differentiate between faeces and flatus

Red flag symptoms of cauda equina syndrome

When a patient presents to their GP or A&E department, he/she may not be displaying all of the symptoms of cauda equina syndrome, as mentioned above. There are, however, certain red flag symptoms that should alert medical practitioners to the possibility of cauda equina compression. If these red flag symptoms are present together, it should quickly prompt further investigations.

The red flag symptoms of cauda equina syndrome are:-

  • Recent onset of urinary dysfunction
  • Saddle anaesthesia (numbness in the perineum, buttocks and genitals)
  • Severe or progressive neurological deficit in the lower extremities (e.g. severe restriction of straight leg raise)

Investigating cauda equina syndrome

When cauda equina syndrome is suspected, the investigation of choice is an MRI scan. Even resident neurosurgeons cannot always tell if a patient has cauda equina syndrome from the clinical features alone. There is approximately a 43% false positive rate, so doctors often believe a patient has CES, when in actual fact a different condition is present altogether. It is for this reason that accurate imaging tests are vitally important.

Depending upon the urgency of the clinical situation, the scan needs to be performed on either an emergency or urgent basis.

When deciding if the patient must be treated on an urgent or an emergency basis, medical practitioners must establish whether or not their condition is incomplete or complete. Incomplete cauda equina syndrome (CES-I) is the initial stage of the condition and means the patient retains some bladder control. Complete cauda equina syndrome (CES-R) is the second and final stage of the condition, and means the patient is in retention and has no control over their bladder.

Complete and incomplete cauda equina syndrome is explored in more detail below.

Incomplete and complete cauda equina syndrome

The importance of distinguishing between incomplete and complete cauda equina syndrome was highlighted in an article by Gleave and Macfarlane.

Incomplete cauda equina syndrome is characterised by urinary difficulties of a neurogenic origin, including altered urinary sensation, loss of desire to void, poor urinary stream and a need to strain in order to micturate.

Complete cauda equina syndrome is characterised by painless urinary retention and overflow incontinence. Implicit in this is that the bladder is no longer under executive control. There is no sensation and so the patient does not feel any pain and is not aware when their bladder is full. Eventually the bladder will become so full that urine leaks out.

It is accepted that patients with incomplete cauda equina syndrome will progress to a complete one. This happens because the compressed nerves gradually become more and more deficient in oxygen. In medical terms, this is called ischaemia. Eventually the nerve roots will become so deficient in oxygen that they die, after which function will be lost altogether.

Therefore cauda equina syndrome needs to be treated while the condition is still incomplete, as this will give a patient the best chance of making a recovery. Once the condition is complete, it will be difficult to reverse the damage.

Treating cauda equina syndrome

Cauda equina syndrome must be treated with surgical decompression of the dural sac by discectomy. Again, dependant on the clinical presentation, the surgical indication is either emergency or urgent if the patient is still incomplete, emergency surgery is required, but if the patient is in retention, urgent surgery will suffice.

The operation of choice is usually a laminectomy followed by a discectomy. For those surgeons who are experienced in microsurgery, a lumbar micro discectomy is a reasonable alternative.

Timing of treatment what do the experts say?

As mentioned above, it is important that cauda equina syndrome is treated while the condition is still incomplete. Medical experts are at odds as to the amount of time it takes for the condition to progress from incomplete to complete.

In 2000, an analysis by Ahn et al reviewed 322 cauda equina patients. The analysis concluded that there was significant improvement in recovery of motor, sensory and pelvic autonomic deficits (bowel, bladder and erectile function in males) in patients treated within 48 hours of the onset of symptoms compared to those treated after 48 hours.

In 2004, a review by Kohles and Polissar et al criticised Ahn, saying it understated 'the value of surgical intervention'. The review recommended surgery within 24 hours of the onset of symptoms.

Other medical experts such as Todd et all have also advocated surgery within 24 hours. But some such as Jennett and Hussain suggest that emergency surgery is not justified, and will not produce a different outcome to urgently operated patients.

There is, therefore, considerable uncertainty in the literature regarding surgical outcomes in relations to timing of the operation. It is, however, reasonable to state that surgery is best performed when the neurological deficient is least.

Timing of cauda equina syndrome surgery

Despite the indecision amongst medical experts, it is standard practice to treat patients with incomplete cauda equina syndrome as an emergency.

Indeed, patients who undergo surgery when the syndrome remains incomplete are true emergencies and require emergency scanning and emergency surgical intervention, even if that requires an operation during the night. This will give the best opportunity to prevent the incomplete syndrome deteriorating into CES with retention.

In a patient where the cauda equina syndrome is complete and there is evidence of urinary retention the basis for investigation and surgery becomes urgent rather than emergency. It is fair to say that even in the case of those patients who have progressed to urinary retention, up to 70% of them will enjoy improvement in bladder function, but whether this is secondary to neurological improvement or adaptation of the individual to their condition is uncertain.

Delayed treatment of cauda equina decompression surgery

If cauda equina decompression surgery is delayed, a patient may progress from the incomplete stage to the complete stage while in a medical environment. This will be very troubling, as once the condition has become complete there is little that can be done. Treatment can still be carried out on an urgent basis, but this will not be particularly effective as the nerves will be irreparably damaged.

Once the condition has become complete, a patient will be left with permanent neurological complications. The severity of these problems will differ from patient to patient, but will involve some or all of the following:-

  • Partial or total paralysis in the leg
  • Urinary dysfunction with the need for intermittent self-catheterisation
  • Bowel dysfunction with either constipation or incontinence
  • Sexual dysfunction with loss of sensation and inability to achieve orgasm/maintain an erection
  • Chronic back pain
  • Psychological injuries

Does a delay amount to medical negligence?

Knowing that earlier treatment could have prevented cauda equina complications will be very hard to cope with. But will a delay in treatment amount to medical negligence?

The answer depends whether or not a patient's condition was incomplete or complete when he/she presented. For example, if a patient arrives at A&E and he/she is already in retention, treatment does not need to be provided on an emergency basis as the dye is already cast. If, on the other hand, a patient arrives with incomplete cauda equina syndrome, there must not be a delay in diagnosis and surgical intervention.

If there is a delay in this is the fault of medical practitioners, the standard of care will be deemed unacceptable. For example, doctors may fail to make a diagnosis, fail to refer a patient for an emergency MRI scan, fail to interpret the test results accurately, or fail to carry out immediate treatment. If such medical errors cause a patient to suffer injuries that could otherwise have been avoided, there will be a case of medical negligence.

Can I claim for cauda equina syndrome medical negligence?

If you suspect that your cauda equina syndrome was negligently managed by medical professionals, you will want to know whether or not you can make a claim. To find out, you simply need to contact a solicitor who specialises in such claims.

A medical negligence lawyer will listen to the details of your medical care before advising upon the options open to you. If there is a case to be answered, your solicitor will begin a claim on your behalf, working to obtain the compensation to which you are legally entitled.

This compensation cannot give you your health back. Nevertheless, it will provide some form of redress. It will also recover all the money you have lost because of your injuries, including past and future loss of earnings. This financial provision will be a great help, particularly if your injuries have affected your capacity to work.

Contact us today

To speak to a solicitor about claiming compensation for cauda equina syndrome, please get in touch with us today.

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