Research Review By Dr. Michael Haneline©


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Date Posted:

February 2019

Study Title:

Assessment and management of cauda equina syndrome


Greenhalgh S, Finucane L, Mercer C & Selfe J

Author's Affiliations:

Bolton NHS Foundation Trust, United Kingdom; Sussex MSK Partnership, UK; Western Sussex Hospitals NHS Foundation Trust, UK, Department of Health Professions, Faculty of Health, Psychology and Social Care, Manchester Metropolitan University, UK.

Publication Information:

Musculoskeletal Science and Practice 2018; 37: 69-74.

Background Information & Summary:

This paper is an overview of cauda equina syndrome (CES) that highlights the challenges faced by clinicians (including chiropractors, physiotherapists and others) in recognizing and managing this condition.

CES is a rare condition that has been reported to occur in one patient annually for every 50,000 patients seen in primary care in the UK – a rate of approximately 0.002%. On the other hand, a CES rate of 3.5% was reported during an 18-month period in a Primary Care Interface service in the UK in which 28 CES patients were managed as emergency cases and referred to a specialist spinal service. CES is so rare that it has been suggested that a general medical practitioner will likely only see one CES patient in their entire career, although spine-care practitioners should undoubtedly see more.

Unfortunately, approximately one fifth of CES patients will have a poor outcome that involves continuing treatment for bladder, bowel and sexual dysfunction, as well as significant associated psychosocial consequences. Therefore, it is imperative that portal of entry clinicians recognize CES cases early and refer them urgently for appropriate care.

CES is most commonly caused by lumbar disc herniation and occurs most frequently in people between the ages of 31 and 50. Other possible causes include spinal stenosis, tumours, cysts, infection or anything else that can narrow the spinal canal.

CES can be difficult to recognize in clinical practice and the most commonly used diagnostic model – the system of Red Flags – has been widely criticized as being ineffective (1). Furthermore, systematic reviews have reported on the diagnostic accuracy of Red Flags as being low, making them poor predictors of CES and also other serious lower back conditions.

There has been little consensus on how to define CES, although Todd and Dickson (2) recently described 5 clinical characteristics of CES that are becoming increasingly recognized. The 5 characteristics are as follows:
  1. Bilateral neurogenic sciatica – lower back pain and/or unilateral/bilateral leg symptoms may be present. EDITOR’S NOTE: in cases I have reviewed in the literature and as a legal expert – be on the lookout for unilateral sciatica that BECOMES bilateral – this certainly warrants careful evaluation!)
  2. Reduced perineal sensation – affecting the perineum and saddle region is one of the most commonly reported symptoms (this is often missed because clinicians don’t ask about it specifically!).
  3. Altered bladder function leading to painless urinary retention – another commonly reported symptom which can range from increased urinary frequency, difficulty in micturition, change in urine stream, urinary incontinence and urinary retention.
  4. Loss of anal tone – may be evident if a patient reports bowel dysfunction, including fecal incontinence, inability to control bowel movements and/or inability to feel when the bowel is full with resulting overflow.
  5. Loss of sexual function – is not widely discussed in the literature, but is an important aspect of health and wellbeing that needs discussion with patients, despite the potential embarrassment for both patient and clinician.

Patient History:

The patient history is the most important part of the CES examination, since early symptoms are often subtle and vague. However, history taking is complicated by the fact that a patient in severe pain may not see the relevance of personal questions about private issues like bladder or sexual function (3). The authors therefore recommend that doctor-patient communication in these cases should involve clear and unambiguous terms that are not easily misunderstood. For instance, a patient may not know what ‘saddle numbness’ means, so an explanation using other terms may be required. A qualitative study found that male patients understood what was meant by the question ‘Do you have a change in ability to get an erection or ejaculate?’; whereas, when questioned about ‘problems with sexual function’ all the participants thought the question had to do with being sexually active.

To facilitate communication between the clinician and a CES patient, reference card questions are available that can be replicated and given to at risk patients. In addition to clear questions about CES symptoms, the reference card also contains information on timely action to be taken if CES symptoms develop. These cards are available as a free download in 30 different languages on the Musculoskeletal Association of Chartered Physiotherapists (MACP) web site - HERE.

Todd and Dickson (1) described the four stages of CES, which include:

CESS Suspected:
  • Bilateral radicular pain
CESI Incomplete – Urinary difficulties of neurogenic origin:
  • Altered urinary sensation
  • Loss of desire to void
  • Poor urinary stream
  • Need to strain to micturate
CESR Retention – Neurogenic retention of urine:
  • Painless urinary retention and overflow incontinence where the bladder is no longer under executive control
CESC Complete:
  • Objective loss of cauda equina function
  • Absent perineal sensation
  • Patulous anus (spread open)
  • Paralyzed insensate bladder and bowel
The authors stressed the importance of recording the chronology of developing CES symptoms/signs and mentioned that just because a patient’s pain improves does not necessarily mean that their CES symptoms are improving.

CES symptoms can also be the result of comorbidities (ex. diabetes and infection), prior surgery, psychological issues, and others, so all relevant questions become important during history taking.

Physical Examination:

A complete, pertinent neurological examination should be performed on any patient suspected of having CES that includes an assessment of dermatomes, myotomal strength, reflexes as well as upper motor neuron tests to rule out any central nervous system disorders.

Many authorities and guidelines consider digital rectal examination (DRE) to be an essential part of evaluating the loss of anal sphincter tone; however, the evidence for its use is weak and some question whether it should be included in a CES examination. A study that compared findings of decreased anal tone and the presence of cauda equina compression on MRI scan showed no direct correlation (4). Furthermore, physical tests for anal tone have been shown to have variable reliability as well as low sensitivity and specificity. Despite this controvertible evidence, not performing DRE on a patient with CES may leave the clinician open to challenge and possible litigation because of its wide acceptance and inclusion in guidelines.

The examination of sensory disturbances in the saddle region has been shown to be a more valid and reliable indicator of CES than DRE. Thus, sensation to light touch and pin prick throughout the saddle region must be tested as part of a CES examination. Regions to be tested include the buttocks, inner thighs and perianal region. The authors emphasized that these intimate tests should only be performed by a trained clinician who is accompanied by a chaperone.

Summary and Guidance:

Given the potentially devastating, negative effects that may occur to a patient when a clinician mishandles a CES case, plus the resulting strong possibility of litigation against the clinician, it is imperative that these patients are managed properly. Nevertheless, due to the rarity of the condition, some clinicians may become complacent and mis-diagnose a CES case, especially when the patient’s symptoms are vague. A CES diagnosis may even be missed in the presence of obvious symptoms/signs for a variety of reasons, for instance:
  • the patient’s symptoms being vague or masked by severe pain;
  • failure of the clinician to ask sensitive questions or perform examination procedures that are embarrassing to both the clinician and patient;
  • the patient refusing to report embarrassing symptoms; or
  • the clinician performing an incomplete or otherwise inadequate CES examination.
Any patient who has unilateral or bilateral radicular pain and/or dermatomal reduced sensation and/or myotomal weakness is at risk for developing CES. If the patient’s symptoms are accompanied by changes in bladder or bowel function, even if the changes are minor, CES should be suspected. The patient should be referred for emergency MRI that must be carried out on the same day to confirm or negate CES, and when necessary, surgery should be performed as soon as possible. “Nothing is to be gained by delaying surgery and potentially much to be lost; surgery should be carried out as soon as is practically possible” (5). To avoid a potentially devastating outcome, time is of the essence in CES cases and the patient must be managed according to emergency protocols that every clinician should already have in place.

Additional References:

  1. Underwood M, Buchbinder R. Red flags for back pain. BMJ 2013; 347: f7432.
  2. Todd NV, Dickson RA. Standards of care in cauda equina syndrome. Br J Neurosurg 2016; 30(5): 518-22.
  3. Greenhalgh S, Truman C, Webster V, Selfe J. An Investigation into the Patient Experience of Cauda Equina Syndrome (CES). Physiother Practice Res 2015; 36(1): 23-31.
  4. Gooding B, Higgins M, Calthorpe D. Does rectal examination have any value in the clinical diagnosis of cauda equina syndrome? Br J Neurosurg 2012; 27(2): 156-9.
  5. Germon T, Ahuja S, Casey A, Rai A. British Association of Spine Surgeons standards of care for cauda equina syndrome. Spine J 2015; 15(3): S2–S4.