Abstract
Introduction
Cauda Equina Syndrome(CES) is a potentially disabling condition caused by compression of the thecal sac in the lumbar spine. Traditional teaching suggests red flags include back pain, sciatica, saddle anaesthesia and bladder disturbance. Current guidelines from the British Association of Spinal Surgeons recommend prompt investigation with MRI should these symptoms be present.
Method
A retrospective electronic case note review was undertaken from a one-year period to identify patients referred to the on call orthopaedic team with suspected CES and were investigated with MRI. Notes were reviewed for the presence of each clinical characteristic and correlated with MRI findings.
Results
334 referrals underwent urgent MRI with 25 scans showing CES. Poor statistical association was observed with unilateral leg pain (sensitivity 0.28, specificity 0.48), back pain (sensitivity 0.92, specificity 0.13) and bladder dysfunction (sensitivity 0.72, specificity 0.36). Much closer statistical association was seen with bilateral leg pain (sensitivity 0.6, specificity 0.7, OR 5.03, 95% CI 2.16-11.68, p0.0002), leg weakness (sensitivity 0.68, specificity of 0.72, OR 5.35, 95% CI 2.23-12.85, p0.0002), leg sensory deficit (sensitivity 0.72, specificity 0.60, OR 3.79, 95% CI 1.54-9.36, p0.004) and altered perianal sensation (sensitivity 0.6, specificity 0.67, OR 3.03, 95% CI 1.31-6.99, p 0.009)
Conclusions
The diagnostic accuracy for some conventional red flag characteristics in CES is low. In our series back pain, unilateral sciatica and bladder disturbance showed low predictive value while bilateral sciatica, saddle anesthesia and lower limb sensorimotor deficits showed closer association and therefore should be closely evaluated for when reviewing such patients.
Back pain and leg weakness