Whilst Cauda Equina Syndrome is a relatively rare condition, it is a fairly common source of Clinical Negligence claims. In this article Jonathan Fuggle explores some of the issues that commonly arise when dealing with CES claims.
What is Cauda Equina Syndrome?
Cauda Equina means “tail of the horse”. It refers to the anatomy at the terminal end of the spinal cord where a mass of nerves branch off the conus. Although they are protected, the nerve roots at this point can become compressed resulting in a condition called Cauda Equina Syndrome. Compression of these nerve roots can cause a number of typical symptoms such as: -
- Bladder Disturbance (including inability to urinate, difficulty initiating urination, decreased sensation and loss of control)
- Bowel Disturbance (including incontinence, constipation and loss of anal tone and sensation)
- Sciatica (lower back pain or pain in buttock, or various parts of the leg and foot)
- Saddle sensory changes (numbness in the groin area)
- Loss of sensation and motor function weakness in the legs
- Reduced or absent leg reflexes
What Causes Cauda Equina Syndrome?
The condition can be caused by any condition that results in direct irritation or pinching of these nerve roots such as: -
- Injury or Trauma
- Herniation of lumbar intervertebral discs
- Tumours adjacent to the spinal cord
- Localised bleeding or infection near the spinal cord
The diagnostic challenge
CES is clinically diagnosed from the presence of the characteristic symptoms described above. The condition can be confirmed using neurological tests (e.g. nerve conduction velocity or electromyography). Alternatively CT or MRI scanning can show compressed spinal cord tissue.
The challenge facing clinicians is that many patienst with CES will present without a full complement of classic symptoms especially if there is only be a partial compression of the cauda equina (Cauda Equina Syndrome Incomplete or CESI). Various degrees and combinations of the usual symptoms result in a range of different presentations. For example patients can present with symptoms of sciatica and loss of sensation / weakness in their legs. Whilst this could be due to the onset of CESI those same symptoms may well be consistent with other causes such as underlying disc degeneration.
Treatment of Cauda Equina Syndrome
Cauda Equina syndrome can lead to permanent dysfunction of the legs as well as permanent bladder and bowel dysfunction. Once the cause of the CES has been determined, management usually involves operative intervention to release compression on the nerve root. Lesion de-bulking followed by chemo-radiotherapy may be required where the cause is a tumour. Anti inflammatory drugs and antibiotics will be appropriate in cases where the cause is due to an inflammatory process or infection.
The time window for effective intervention
There are differing views. One study concluded that the key issue is the time at which the lesion probably became complete (a condition known as Cauda Equina Syndrome with Retention – CESR). CESR is distinguished by the patient having new symptoms of painless urinary retention and overflow incontinence. By the time that those new symptoms are present some academic studies have concluded that the timing of surgery has no bearing on the outcome. Certainly Defendants have successfully defended claims by contending that, by the time that surgery should have been performed, it was already too late for it to have altered the outcome. See the recent case of Hussain v Bradford Teaching Hospitals NHS Trust (2011 EWCH 2914).
Establishing a start time
It is common for there to be disagreement between the parties as to the time at which the cauda equina lesion first occurred. Indeed there is a notable lack of consistency in the definition of cauda equina lesion. A useful definition in one study is that there is deemed to be a cauda equina lesion where one or more of the following are present:
- bladder and/or bowel dysfunction
- reduced sensation in the saddle area
- sexual dysfunction, with possible neurologic deficit in the lower limb
The importance of factual causation
A key line of enquiry for Defendant solicitors will be a careful investigation of the factual causation position. This will include investigating: -
- When the lesion probably first occurred?
- When reasonably should CES first have been suspected?
- How long would it have taken for an urgent MRI to be performed and reported?
- How long after the MRI would it reasonably have taken to arrange for surgical intervention if appropriate?