Scan-Negative Cauda Equina Syndrome: A Prospective Cohort Study

OBJECTIVE:To describe clinical features relevant to diagnosis, mechanism and aetiology in patients with ‘scan-negative’ cauda equina syndrome (CES). METHODS:We carried out a prospective study of consecutive patients presenting with the clinical features of CES to a regional neurosurgery centre comprising semi-structured interview and questionnaires investigating presenting symptoms, neurological examination, psychiatric and functional disorder comorbidity, bladder/bowel/sexual function, distress and disability. RESULTS:198 patients presented consecutively over 28 months. 47 were diagnosed with ‘scan-positive’ CES (mean age 48yrs, 43% female). 76 ‘mixed’ category patients had nerve root compression/displacement without CES compression, (mean age 46yrs, 71% female) and 61 patients had ‘scan-negative’ CES (mean age 40yrs, 77% female). An alternative neurological cause of CES emerged in 14/198 patients during admission and 4/151 patients with mean duration 25 months follow up.Patients with ‘scan-negative’ CES had more positive clinical signs of a functional neurological disorder (11%‘scan positive’ CES v. 34%mixed and 68%‘scan-negative’, p