In this article, Nicholas Todd, a Neurosurgeon and Spinal Surgeon on MAPS’ expert panel, examines the medico-legal implications of recent national guidance on symptom-only cauda equina syndrome (SO-CES). He explores how updated guidance has changed expectations around diagnosis, referral and treatment, particularly in primary care, and considers the potential impact on standards of care, clinical negligence claims and future litigation involving delayed diagnosis.
The article was originally published in the Medico-Legal Journal on 18/01/26.
Introduction
Patients with a cauda equina syndrome (CES) can present with symptoms and signs of CES or with symptoms of CES without objective signs (symptom-only CES, SO-CES)1. Traditionally it had been thought that a clinical diagnosis of a cauda equina syndrome (CES) requires both symptoms and objective signs of CES. That is no longer the case. Several national guidelines say that in primary care, symptoms of CES should mandate referral to secondary care (for magnetic resonance imaging [MRI]) to diagnose or exclude CES regardless of objective signs of CES.
Indeed, current guidance is that GPs, and others in primary care, should not examine for objective signs of CES (typically perianal sensation (PAS), anal tone (AT) or anal squeeze (AS)). It is also current practice to perform decompressive surgery in patients with SO-CES where there is a large central disc prolapse that is capable of causing CES.
Diagnosis and treatment of SO-CES cases is an advantage to claimant lawyers because the standard of care is less onerous than previously, and causation and quantum will be more favourable because earlier treatment will be associated with better outcomes.
Prevalence
The commonest cause of CES is a large central disc prolapse compressing the cauda equina nerve roots. A small proportion are caused by lumbar spinal stenosis, tumour, fracture or infection.
The incidence of CES in working adults is 7 per 100,000 patient years. Of all patients with low back pain, 0.3% will have CES. In clinically suspected CES, about 20% have clinical and radiological confirmation of CES2.
Clinical diagnosis
There is no universally agreed definition of cauda equina syndrome (CES). CES is a syndrome of symptoms and signs which range from modest cauda equina irritation through to catastrophic neurological and visceral injury.
In cases of acute CES caused by a disc prolapse the following symptoms are found3: back pain, often severe (96%); sciatica (93%), more often unilateral (54%) than bilateral (46%); urinary retention (41%) and bowel dysfunction (39%).
Other bladder symptoms include: incontinence (40%), altered sensation (22%), poor stream (37%) and urinary urgency or frequency (9%). On examination, saddle anaesthesia (complete loss of saddle sensation) is uncommon; reduced saddle sensation occurs in 67% of cases (bilaterally in 63%, unilaterally in 37%).
Change in UK national guidelines
Since 2020, four national guidelines4-7 state that:
(i) symptoms of CES in the absence of objective signs mandate an urgent MRI;
(ii) rectal examination is not necessary in primary care so the assessment of PAS and AT is not required to diagnose CES clinically; an urgent same day MRI should be requested on the basis of symptoms alone; and
(iii) a history to elicit early symptoms of CES is required.
Most, typically young, patients present acutely with symptoms present for hours, days or weeks. Under the revised national guidance4-7 ,in the context of a patient with low back pain and/or sciatica, any new symptom of bladder dysfunction including any change in the pattern of micturition, hesitancy, frequency, dribbling, incomplete emptying, loss of the sensation of passing urine, retention or incontinence, or any subjective change in saddle sensation (genital and/or perianal sensation, including paraesthesia and/or numbness) are symptoms that should now prompt an urgent same day MRI regardless of objective signs.
The latest NICE guidance7 emphasises “difficulty initiating micturition or impaired sensation of urinary flow,” as early symptoms. If those early symptoms are untreated, this can lead to “irreversible urinary retention with overflow urinary incontinence”.
Change in neurosurgical practice
In the more distant past, some spinal surgeons tended not to operate in the absence of objective signs, but that is no longer good practice. In the cohort study recruited in 2019, 27% had symptoms of CES with normal PAS on examination (SO-CES)3.
Management in primary care
In a patient with low back pain, sciatica or neurogenic claudication it is essential to establish whether there are any new bladder problems (the range of potential symptoms is set out above) and whether there is any alteration in saddle area sensation (perianal and genital sensation) .
If the answer to either of these questions is yes, the patient must be referred for urgent same-day MRI scanning. Examination for altered PAS and AT cannot exclude CES and does not need to be performed in primary care8.
It is essential to record what symptoms were asked about. Delayed diagnosis is a major cause of clinical negligence claims. GPs commonly record “no red flags”. The wise GP will now record that there was an enquiry into early symptoms of CES8. If there is litigation in respect of an alleged delay in referral, GPs should be able to show that an enquiry of all potentially relevant symptoms of early CES (see above for details) was made and not just questions about symptoms of late CES such as urinary incontinence or saddle anaesthesia.
Standard of care for doctors
The two fundamental judgments are Bolam9 and Bolitho10.
In Bolam, McNair J said a doctor “… is not guilty of negligence if he has acted in accordance with a practice accepted as proper by a respectable body of medical men skilled in that particular art…putting it the other way round, a man is not negligent, if he is acting in accordance with such a practice, merely because there is a body of opinion who would take a contrary view.”
In Bolitho, the principle that the basis of assessing duty of care is expert opinion was qualified by Browne-Wilkinson SCJ:
“It is only where a judge can be satisfied that the body of expert opinion cannot be logically supported at all that such opinion will not provide the benchmark by reference to which the defendant’s conduct falls to be assessed.”
Duty of care for doctors is determined by expert evidence that must be reasonable, responsible and logical (rational). Of course, ultimately, the duty of care in an individual case is determined by a court and the Judge can reject all expert opinion.
In Hucks v. Cole11, Sachs LJ said:
“When the evidence shows that a lacuna in professional practice exists by which risks of grave danger are knowingly taken, then, however small the risk, the court must anxiously examine that lacuna, particularly if the risk can be easily and inexpensively avoided. If the court finds, on an analysis of the reasons given for not taking those precautions that, in the light of current professional knowledge, there is no proper basis for the lacuna, and that it is definitely not reasonable that those risks should have been taken, its function is to state that fact and where necessary to state that it constitutes negligence…The court must be vigilant to see whether the reasons given for putting a patient at risk are valid in the light of any well-known advance in medical knowledge, or whether they stem from a residual adherence to out-of-date ideas.”
The legal basis of national guidelines
Many UK authorities offer guidelines for clinical management. The most authoritative emanates from the National Institute for Health and Care Excellence (NICE). NICE guidelines can promote good medical practice. Doctors have a duty to keep up-to-date and advice from the General Medical Council (GMC) in 202112 advised doctors to “take account of the clinical guidelines published by NICE….”
There can be a difference in the extent to which NHS organisations and individual doctors have to adhere to NICE guidance. There is a statutory duty upon NHS England to implement NICE guidance within three months of publication13. The general principle in respect of state institutions and national guidance can be found in Fisher14, where Dyson J found that the failure of a public sector organisation to implement guidance from the Secretary of State could only be lawful if there was a “special factor which it considered exceptionally justified departure”. NICE guidance has the same status. In Rose15, Jay J found that NICE guidance “has the same status as that of the Secretary of State in ex parte Fisher… [and] it would surely follow that the CCG could not disagree with NICE; it would need to find an exceptional basis for not following the NICE recommendation”.
Individual doctors have an overriding responsibility to make decisions appropriate to the care of the individual patient and, although NICE guidance should be taken into account, this guidance must not be followed if it is not in a patient’s best interests. As the then Chair of NICE said16, “there appears to be confusion about the circumstances in which it is obligatory for… [doctors] to follow NICE guidance… the quick answer is ‘never’”.
It is not possible for guidelines to regulate every clinical encounter. Treatments shown to be effective at a population level might not be best for individual patients, and some guidelines may be aspirational and not achievable in all eligible cases. There has been an increased willingness for courts to follow national guidelines as objective tests in determining the legal standard of care. In Fotedar17,Gray J gave greater weight to guidance from the Royal College of Obstetricians and Gynaecologists than the expert witnesses in a case of vacuum extraction delivery before the cervix is fully dilated, saying: “protocols such as these appear to me to give valuable guidance as to what is and what is not acceptable practice”.
Courts understand that NICE guidelines are developed through a detailed and structured process which is beyond the resources of most other organisations. Weight will rightly be given to such guidelines, but doctors will not be in breach of their duty of care to a patient if they can demonstrate why their treatment differed and that the divergence was reasonable, responsible and logical.
In O’Brien18, the patient had renal failure with worsening sepsis. The defendant doctor gave a dose of gentamycin (400 mg) that was much higher than NICE guidance. Mr O’Brien developed ototoxicity as a consequence of the high dose gentamycin, which would not have occurred with the lower dose recommended in the guidelines. The claim was dismissed because there were good and cogent reasons for departing from the national guidance, mainly that the more cautious dose had been tried yet sepsis was progressing and the higher dose was mandated because the risk of infection was greater than that of ototoxicity.
Clinicians must take account of national guidelines when treating patients. Any departure from a relevant guideline must be justified and a court will expect an explanation for the departure from the clinician. It remains the role of the courts to consider all available evidence when determining the standard of care.
An Illustrative Case
SJ was a 2021 case that considered duty of care for SO-CES in events of 201519. SJ was a 41-year-old woman. There was an accident at work; immediately following the accident there was a “burning” pain radiating down the right leg and into the genitalia on the right side. Two weeks later, SJ was assessed by an experienced orthopaedic registrar in A&E. The symptoms were perianal paraesthesia with no urge to pass urine nor to open the bowels. A thorough clinical examination showed no objective signs of CES. The bladder emptied to completion. In the absence of objective signs, a diagnosis of CES was discounted, no MRI was performed and she was discharged. An MRI performed 15 days later demonstrated a large central disc prolapse at L5/S1 causing severe compression of the cauda equina nerve roots. She was recalled but, by that time, she had had painless urinary incontinence for about five days, with other severe neurological deficits. Surgery was performed with no neurological improvement. There was permanent bladder, bowel and sexual dysfunction, with neuropathic pain in the pelvis and legs, motor weakness, balance problems, fatigue and a depressive illness. There were five spinal experts (three neurosurgeons [one of whom was the author of this article] and two orthopaedic spinal surgeons). All three neurosurgeons said that in 2015 the duty of care was to perform an MRI within 24 hours; one orthopaedic expert said within one week (in court reducing this to four days, which was not well received by the judge); one orthopaedic expert said that it was reasonable practice to scan within two weeks. The judge accepted that an MRI within two weeks was reasonable and found in favour of the defendant. This in part reflects judicial practice that, even where a body of appropriate opinion says that the act or omission was negligent, a court will attach substantial weight to expert opinion that advises that an alleged negligent act or omission is reasonable. As will be discussed below, this case would very probably have been decided in favour of the claimant if the events had occurred after 2020.
Discussion
I am not aware of any published judgment that has considered duty of care for SO-CES since the new national guidelines were introduced. In the 2016 case set out above19, the standard of care for SO-CES was found to be an MRI within two weeks. Unfortunately for the claimant, she developed severe, irreversible CES before the MRI was performed.
The first national guideline, issued in 20204, said that SO-CES cases should immediately be referred to the secondary service for an MRI. Examination for objective signs of CES (PAS, AT, AS) is not needed and should not be performed in primary care. The same guidance was also issued by NICE in 20235 and 20257 and by GIRFT in 20236. Since 2020, four guidelines from various national authorities have said that SO-CES should have immediate MR imaging. Although it is not specifically stated, the implication is that those with positive MRIs (showing a disc prolapse that compresses the cauda equina nerve roots) should have emergency surgery.
In future cases, Judges will recognise the authority of four national guidelines all saying the same thing, with no national guideline suggesting anything different. This will almost certainly satisfy a Bolam-competent (reasonable and responsible doctor) test. It would also satisfy a Bolitho test of logic because it is well recognised that no symptom or sign, or combination of symptoms and signs, accurately predicts a positive MRI (the diagnosis of CES is a clinical suspicion supported by MRI). It also reflects the change that has occurred in surgical practice. When I was in training (before 1991), no-one with SO-CES was offered surgery. In 2019, 27% of CES cases undergoing emergency surgery had SO-CES3. As a first-order estimate, this probably represents most of the SO-CES cases that were seen in 2019. If so, one can say that, on a balance of probabilities, an SO-CES case in 2019 (and by presumption since 2019) will have emergency surgery.
The current standard of care for doctors in primary care is to identify any and all symptoms of CES, which most commonly means any new change in the pattern of micturition or PAS. The court might infer that, if there is no record of this, the questions were not asked. There is a specific duty to ask about early symptoms, not symptoms of severe CES such as urinary incontinence or saddle anaesthesia.
This emphasis on identifying symptoms of early CES makes proving that there was a breach of duty of care more favourable for claimants and less so for defendants. Moreover, causation will be more favourable for claimants because surgery where there are no, or minimal, objective signs will have a more favourable outcome than in those with objective signs, particularly signs of severe and often irreversible CES.
Citation
Todd NV. Symptom-only cauda equina syndrome. A medicolegal assessment of new national guidelines. Medico-Legal Journal. 2026;94(1):39–42. doi:10.1177/00258172251405164.
Original Article
Symptom-only cauda equina syndrome: A medicolegal assessment of new national guidelines
Nicholas Todd
Medico-Legal Journal 94(1) 39–42
© The Author(s) 2026
DOI: 10.1177/00258172251405164
journals.sagepub.com/home/mlj
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