spine
Cauda Equina Syndrome
advanced
6 min
28 marks
6 questions
Clinical Scenario
A 45-year-old woman presents to the emergency department with a 2-day history of worsening low back pain and bilateral leg pain. She now reports difficulty passing urine and has not opened her bowels for 24 hours. On examination, she has reduced perianal sensation bilaterally and a post-void residual of 350mL.
Sagittal T2-weighted MRI demonstrating large L4-5 disc herniation with severe canal stenosis. Axial image shows the disc occupying >50% of the canal with compression of the cauda equina nerve roots. There is obliteration of CSF signal around the roots. This represents cauda equina syndrome requiring emergency surgical decompression.
Image source: Open Access medical literature (NIH/PubMed Central) • CC-BY License
Questions
Question 1 (4 marks)
Describe the MRI findings and define cauda equina syndrome.
Question 2 (5 marks)
What are the clinical features and how do you classify the severity?
Question 3 (6 marks)
What is the optimal timing of surgery and what does the evidence show?
Question 4 (5 marks)
Describe your surgical technique for emergency decompression.
Question 5 (4 marks)
What are the expected outcomes and prognostic factors?
Question 6 (4 marks)
What documentation and consent issues are specific to this condition?
Exam Day Cheat Sheet
Must Mention
- •CES-I (incomplete) vs CES-R (retention) classification
- •Bladder dysfunction is the DEFINING feature
- •Post-void residual >200mL significant
- •Operate ASAP - earlier is better
- •CES-I → CES-R conversion = worse outcome
- •Prognosis depends on pre-op bladder status
- •Document everything (medicolegal)
Common Pitfalls
- •Missing the diagnosis (not checking red flags)
- •Not measuring PVR
- •Delaying surgery
- •Poor documentation
- •Not discussing prognosis realistically
- •Back pain alone is NOT CES