HSIB report highlights safety risks in delayed diagnosis and treatment of cauda equina syndrome (CES)

The Healthcare Safety Investigation Branch (HSIB) has published its national learning report, Timely detection and treatment of cauda equina syndrome.  HSIB’s investigation and report was based on a reference event, in which a woman with red flag symptoms of CES waited four days for an MRI scan, a further ten hours for transfer to a specialist spinal centre and then experienced hours of further delay before undergoing decompression surgery. 

The report highlights safety risks in the NHS which are causing delay in diagnosing and treating patients with spinal nerve compression conditions. These include the lack of NICE guidance and a clear national pathway for CES management, variations in practise and timescales, and difficulties with access to MRI scanning. HSIB’s report recommends changes to reduce the risk of delays in detection and treatment of spinal nerve compression.

Cauda equina syndrome is a medical emergency. Delayed diagnosis and treatment of CES can lead to life-changing physical disability and psychological injury.

What is cauda equina syndrome?

CES or cauda equina syndrome is a rare but serious neurological condition which is caused by compression (or squeezing) of a bundle of nerve roots at the base of the spinal column. These ‘cauda equina’ nerves provide feeling and control to the bladder, bowel, anal and genital areas, and also control the legs and feet. When these nerves are compressed, often as a result of a slipped disc or an injury to the lower back, the patient is at risk of permanent disability. A patient with suspected cauda equina must be referred for an MRI scan, urgent neurosurgical review and emergency surgery to release the pressure on their spinal cord.

Background to HSIB’s cauda equina report and reference event

HSIB has been aware of the potential safety risks associated with the diagnosis and management of cauda equina syndrome since June 2018. By August 2019, repeated safety concerns and further research into CES incidents led HSIB to carry out a national investigation.

The report references a CES safety incident involving a 32-year-old woman who was left with back pain and neurological symptoms after delays in obtaining an MRI scan, onward referral to a regional specialist spinal centre, neurosurgical review and decompression surgery for cauda equina. Within a two-month period, she had visited her GP on six occasions and the hospital twice with pelvic, back and low abdominal pain. She then visited her GP,  the hospital A&E and an out-of-hours GP with increasing pain in her pelvis, abdomen and back, radiating down her leg and into her calf. The two GPs agreed that she had a slipped disc and she was told she should go to the hospital if she experienced any ‘red flag’ symptoms for CES. After an episode of urinary incontinence (red flag symptom) she immediately went to A&E where a consultant agreed with the slipped disc diagnosis and noted a plan for her to have an MRI scan within a week. The MRI scan took place four days later and showed spinal nerve compression. She was referred to an orthopaedic surgeon who saw her later that evening and referred her electronically for neurosurgical review at the regional specialist spinal centre. Three hours later a neurosurgery registrar saw the referral when he logged onto the computer referral system. After discussing the referral with the on-call consultant, who noted significant cauda equina compression on the MRI scan, they arranged emergency transfer of the patient to the specialist centre. The patient was taken by emergency ambulance and arrived at the specialist centre in the early hours of the morning, 12 hours after her MRI scan. The consultant surgeon reviewed the patient at 9am but surgery was delayed until 2.10pm for another priority case and because X-ray facilities were not available in the operating theatre. The patient was left with ongoing pain and neurological symptoms despite intensive rehabilitation.

HSIB’s national report finds safety risks causing delay in diagnosis and treatment of cauda equina syndrome

The reference event clearly illustrates how delays commonly occur in achieving timely treatment for patients with suspected cauda equina syndrome. Despite national standards which say that CES should be suspected in any patient presenting with back pain and/or sciatic pain with any disturbance of their bladder or bowel function, saddle or genital sensory disturbance or bilateral leg pain, HSIB’s investigation highlighted a number of factors which continue to threaten the safety of CES patients at a national level.

HSIB found that diagnosis of CES is not straightforward and many doctors will never have seen the condition before, as it is rare.  CES often presents in ways which are not as clear as the description in general standards or medical textbooks might suggest. Some symptoms of CES, such as bowel and bladder symptoms, are often seen in other conditions.  Patients may find it difficult to describe their symptoms and identify exactly when they began, and for a GP working within a ten minute consultation, taking a full history from a patient and carrying out a clinical examination to exclude other causes of low back pain can take time.

Red flag symptoms are listed for CES and, where they are identified, the patient must be admitted to hospital or referred urgently for specialist assessment.  However, research suggests that waiting for red flags may not be the best way to diagnose or avoid injury from cauda equina syndrome. Some red flags, such as urinary or faecal incontinence, can be indicators that irreversible, neurological damage has probably already occurred. This raises the question of whether it would be more helpful to have guidance describing early features of CES, rather than red flags based on signs that occur when it is already too late to avoid permanent harm from the condition.  In general, doctors do not routinely screen for red flags, but tend to manage the low back pain condition that they see. In addition, safety-netting leaflets advising patients on the symptoms associated with CES are inconsistent.  

NICE provides guidance on low back pain and sciatica, but the guidance does not cover the evaluation of CES. There is no NICE guidance specifically relating to CES, which leads to variation in practise. There is also a lack of standardised diagnostic criteria and management pathways for patients with suspected CES.

Further problems arise once CES is suspected. MRI scanning  is currently the recommended investigation for diagnosing CES and must be carried out as an emergency where CES is suspected, but timeframes vary, and terms, such as ‘emergency scan’ and ‘urgent scan’,  are used interchangeably, with different meanings at different locations. MRI scanning should be available at the patient’s referring hospital 24 hours a day, 7 days a week, but there are often difficulties with getting an MRI scan out of hours. The UK has fewer MRI scanners per person than other European countries. A national lack of trained staff, such as radiographers, often means that local hospitals do not have staff available to carry out an MRI scan outside the working day, and where a hospital has access to an MRI scan it may be owned by an independent organisation which uses it for other patient lists out of hours. Further difficulties exist with accessing specialist spinal or neurosurgical advice.

HSIB found that treatment pathways for CES vary between hospitals and geographical areas. A clear national pathway is needed for management of CES, with appropriate tests and assessments by suitably senior staff, timely MRIs and early communication to ensure the receiving hospital can plan for the patient.  

The report makes various recommendations and safety observations designed to simplify, clarify and prioritise the treatment of patients with CES, including:

• the development of a decision-making tool to help identify suspected cauda equina patients needing immediate MRI;
• prioritising the first MRI slot of the day for suspected CES patients who did not get an emergency scan overnight;
• the development of guidance on defining and prioritising ‘urgent’ and ‘emergency’ requests for MRI scans;
• updating of NICE guidance on low back pain to include symptoms and early management of CES;
• the development of a national cauda equina syndrome pathway;
• 24hr/7day MRI scanning and reporting facilities in relevant hospitals with additional training for radiographers where required;
• clearly worded safety-netting leaflets to be given to patients with low back pain advising what to do if red flag symptoms develop.

Claiming compensation after delayed cauda equina treatment leads to permanent disability

Cauda equina syndrome is rare, but its physical and psychological impact can last a lifetime. We welcome HSIB’s call for national guidance and a dedicated NHS pathway to reduce delays in CES patients’ diagnosis and specialist review and neurosurgical care. Where misdiagnosis and delays have led to avoidable harm and shattered lives, we remain committed to helping the injured restore their independence and rebuild their lives through their legal right to compensation.

If you have suffered severe injury as a result of negligent delays in medical treatment, and you would like to find out more about making a claim, you can talk to one of our specialist solicitors, free and confidentially, by contacting us here.