What is the diagnosis of Cauda Equina Syndrome (CES)?

From the Guidelines

Cauda equina syndrome diagnosis should be made through a combination of clinical evaluation and urgent MRI of the lumbar spine without IV contrast, as it is the most accurate and efficient method to depict soft-tissue pathology and assess spinal canal patency. The diagnosis begins with a thorough neurological examination looking for key symptoms including lower back pain, bilateral sciatica, saddle anesthesia (numbness in the groin and buttocks), bladder or bowel dysfunction, and lower extremity weakness or sensory deficits, as described in the study by Fairbank et al 39.

Key Symptoms

• Lower back pain
• Bilateral sciatica
• Saddle anesthesia (numbness in the groin and buttocks)
• Bladder or bowel dysfunction
• Lower extremity weakness or sensory deficits Urgent MRI assessment is recommended in all patients who present with new-onset urinary symptoms in the context of LBP or sciatica, as suggested by Bell et al 41. A recent study has also shown that a single 3-D heavily T2-weighted fat-saturated sequence protocol can be a rapid and highly sensitive tool for evaluating CES in the emergency department 42.

Imaging Studies

• MRI lumbar spine without IV contrast is the preferred initial study
• MRI lumbar spine without and with IV contrast may be helpful to delineate etiology of CES when underlying malignancy, infection, or inflammation is clinically suspected
• CT lumbar spine without IV contrast can answer the question of whether or not cauda equina compression is present, but is not the first line of imaging
• CT myelography of the lumbar spine can be useful for surgical planning in patients with CES and in patients with significant spinal stenosis on CT lumbar spine without IV contrast, as described in the study 22. If MRI is unavailable, CT myelography can be used as an alternative, but MRI remains the gold standard due to its superior soft-tissue contrast and ability to characterize the etiology of CES, as stated in the study 27. Laboratory tests including complete blood count, C-reactive protein, and erythrocyte sedimentation rate may help identify infection as a potential cause 1. Once diagnosed, cauda equina syndrome requires emergency surgical decompression, typically within 24-48 hours of symptom onset to prevent permanent neurological damage, as emphasized in the study 1. The urgency of diagnosis cannot be overstated as delays in treatment significantly worsen outcomes. Post-surgical management includes physical therapy, pain management, and potentially bladder/bowel retraining depending on residual deficits. Early recognition of this condition is critical, so any patient presenting with a combination of lower back pain and urinary retention should be considered for urgent evaluation 1.

From the Research

Cauda Equina Syndrome Diagnosis

• Cauda equina syndrome is a relatively uncommon condition typically associated with a large, space-occupying lesion within the canal of the lumbosacral spine 2.
• The syndrome is characterized by varying patterns of low back pain, sciatica, lower extremity sensorimotor loss, and bowel and bladder dysfunction 2.
• Red flag symptoms, such as bladder dysfunction, saddle anaesthesia, and sciatica, should lead to high clinical suspicion of cauda equina syndrome 3.

Diagnostic Challenges

• Early diagnosis is often challenging because the initial signs and symptoms frequently are subtle 2.
• Clinical signs of CES, including direct rectal examination (DRE), do not reliably correlate with cauda equina (CE) compression on MRI 4.
• The only reliable way of including or excluding CES is to perform MRI on all patients with suspected CES 4.

Importance of Prompt Diagnosis and Treatment

• Immediate magnetic resonance imaging, within 1 hour of presentation to the emergency department, is crucial in patients with suspected cauda equina syndrome to allow prompt diagnosis and treatment 3.
• Urgent decompressive surgery is usually recommended for the best outcomes, to reduce morbidity and complication rates 3, 4.
• The timing of decompression remains debated, with some studies reporting no significant difference in outcomes between decompression within 24 hours vs. 48 hours, while others emphasize the importance of immediate intervention 5.