Neuron-specific enolase as a Biomarker in Nerve Compression and Cauda Equina Syndrome (BioNCCES) Study.

Background: Cauda equina syndrome (CES) is a neurosurgical emergency, and suspected cases require urgent magnetic resonance imaging (MRI) scanning of the lumbosacral spine. This pilot study explores whether serum levels of neuron-specific enolase (NSE) can predict the degree of nerve compression seen on MRI scanning.

Methods: This was a prospective, diagnostic cohort pilot study of adult patients presenting to the emergency department (ED) in York between February 2024 and July 2024 with symptoms suggestive of CES in the opinion of the treating clinician (eg, back pain, sciatica, perianal paraesthesia, bladder or bowel dysfunction, sexual dysfunction). Patients either self-presented to the ED or had been referred by local primary care doctors or physiotherapists. All patients underwent MRI scanning (or fine-slice computed tomography scan if MRI contraindicated) of the lumbosacral spine and measurement of serum NSE. Imaging was classified as positive if the radiological report described cauda equina compression, nerve root compression or impingement and negative if none of these were described. We compared the serum levels of NSE in patients with positive imaging with those in patients with negative scans.

Results: 98 patients were included. 97 patients had urgent MRI of the lumbosacral spine and 1 patient had fine-slice CT. 52 patients had imaging classified as positive, and 46 patients had scans classified as negative. Patients with positive scans had a mean serum NSE level of 7.16 µg/L (SD 2.54) and those with negative imaging had a mean serum NSE level of 6.82 µg/L (SD 2.91). NSE did not demonstrate any ability to discriminate between patients with positive and negative imaging with an area under the receiver operating characteristic curve of 0.542.

Conclusion: The study shows that serum NSE is not a useful biomarker in the management of patients presenting to an ED with symptoms of CES.