HSIB releases a report following a national investigation into timely detection and treatment of cauda equina syndrome

The Healthcare Safety Investigation Branch (HSIB) has released a report, which examines the potential causes of delay in diagnosing of Cauda Equina Syndrome (CES).

The report was conducted following multiple incidents where it was identified that delays in diagnosing CES had resulted in poor outcomes. 

The Cauda Equina is located at the lower end of the spinal cord, where it splits into individual nerves (Latin for horse’s tail). CES is a condition in which there is narrowing of the spinal cord at this level. Damage to this area can lead to permanent problems unless it is treated as an emergency. It is an injury which can result in significant levels of compensation in clinical negligence claims, sometimes exceeding over £500,000. Unfortunately, cases of delayed diagnosis of CES are very common.

Reference Event

The report focuses on the example of a patient who had presented to her GP in and around February 2019 with increasing pelvic pain. The Claimant had previously undergone investigations for pain that was suspected to be due to endometriosis (and it was assumed this was likely the explanation for her pelvic pain).

Upon development of severe pain, the Claimant contacted the out of hours GP at the local hospital where is was suspected that she may have been suffering from a slipped disc. She was advised to visit her own GP the following day. Her GP reviewed and noted lower back pain down to the right thigh as well as numbness and pins and needles in the left thigh (bilateral changes) however, the patient was not suffering saddle anaesthesia and had not lost any control of her bladder or bowel functions. Red flag symptoms were explained to the patient and she was told to go straight to hospital if any occur. It is said that whilst leaving the GP surgery, the patient suspected that she may have had a period of incontinence and went straight to the local emergency department.

The emergency department consultant agreed the diagnosis of spinal disc protrusion and the documented plan was for an MRI scan as an outpatient within 1 week. The scan took place four days later.

On the day of her MRI appointment, the scan was completed at 15:15hrs. At 17:45 it was reported as showing L5/S1 spinal nerve compression. At 19:12 hours, the orthopaedic doctor referred the patient (using an electronic referral system) to the neurosurgery department at a regional specialist centre. At 22:00 hours, the referral was picked up when the neurosurgery registrar logged on to the system. Following discussion with a consultant, arrangements were then made for the patient to be transferred to the specialist centre as an emergency as it was of the consultant’s view that the MRI scan showed an almost 75% occlusion of the spinal canal.

Surgery did not take place until 14:10 hours the following day (almost 12 hours after the diagnosis of 75% occlusion of the spinal canal). Problems were the lack of available theatre overnight and unavailable radiographer for theatre the following morning.

The Claimant underwent rehabilitation but is said to continue to suffer with ongoing back pain and neurological symptoms (primarily urinary issues).

Outcomes of the Investigation

The investigation found that there were inefficiencies in the diagnostic pathway. There were local difficulties in obtaining 24/7 MRI scans and the threshold for requesting an MRI scan was largely dependent on the individual clinician’s suspicions as opposed to there being any clear guideline to mandate this.

Once the decision was made that the patient needed to be referred to the specialist centre, this was done via an electronic system, which relied on the receiving centre to wait for someone to access the system. In this case, the referral was received 3 hours after it had been made (this was despite the software having the ability to trigger a phone call – a function that was not being utilised).

Once the results of the MRI were available, there were then difficulties in arranging for the patient to receive emergency transfer to the specialist centre. The patient’s case was still not prioritised to be the first case of the day and there was limited operating theatre space with it being the weekend. Once the theatre became available, there was no radiographer available until the afternoon to assist in theatre.

Recommendations made by HSIB

HSIB have made the following safety recommendations to various bodies following this investigation:

1. A decision-making tool should be developed to support the identification of patients who need an immediate MRI for suspected cauda equina syndrome.
    
2. Guidance is developed stating that all hospitals should reserve the first MRI slot of the day for patients with suspected cauda equina syndrome who do not meet the criteria for emergency/immediate scan overnight.
    
3. There should be national guidance on how to identify how “urgent” and “emergency” requests for scans are defined and prioritised.
    
4. The NICE Guidelines for lower back pain should be updated to include symptoms and initial management of cauda equina. This should include the role of supplemental investigations such as bladder scanning.
    
5. A national cauda equina pathway should be developed.

The organisations were asked to respond with their thoughts on the recommendations. Presumably they will have to consider firstly whether they agree with all the recommendations, and if they do, what changes need to be made to allow all NHS bodies to realistically implement them. There is no point making a recommendation if the resources of the NHS do not permit implementation.