Scan-Negative Cauda Equina Syndrome: A Prospective Cohort Study
Ingrid Hoeritzauer1, Alan Carson2, Patrick Statham2
1From the Centre for Clinical Brain Sciences (I.H., A.C., A.K.D., J.S.), University of EdinburghDepartments of Clinical Neurosciences (I.H., A.C., P.S., A.K.D., J.S.), Neurosurgery (P.S., A.K.D.), Urology (V.G.), Gastroenterology (M.E.), and Neuroradiology (D.S.), Western General HospitalDepartment of Rehabilitation Medicine (A.C.), NHS Lothian, EdinburghDepartment of Uro-Neurology (J.N.P.), The National Hospital of Neurology and Neurosurgery and UCL Queen Square Institute of Neurology, LondonEdinburgh Spinal Surgery Outcomes Study Group (I.H., P.S., A.K.D.), UK. Ingrid.hoeritzauer@ed.ac.uk.
Objective:
To describe clinical features relevant to diagnosis, mechanism, and etiology 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 center comprising semi-structured interview and questionnaires investigating presenting symptoms, neurologic examination, psychiatric and functional disorder comorbidity, bladder/bowel/sexual function, distress, and disability.
Results:
A total of 198 patients presented consecutively over 28 months. A total of 47 were diagnosed with scan-positive CES (mean age 48 years, 43% female). A total of 76 mixed category patients had nerve root compression/displacement without CES compression (mean age 46 years, 71% female) and 61 patients had scan-negative CES (mean age 40 years, 77% female). An alternative neurologic 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 neurologic disorder (11% scan-positive CES vs 34% mixed and 68% scan-negative, p < 0.0001), were more likely to describe their current back pain as worst ever (41% vs 46% and 70%, p = 0.005), and were more likely to have symptoms of a panic attack at onset (37% vs 57% and 70%, p = 0.001). Patients with scan-positive CES were more likely to have reduced/absent bilateral ankle jerks (78% vs 30% and 12%, p < 0.0001). There was no significant difference between groups in the frequency of reduced anal tone and urinary retention.
Conclusion:
The first well-phenotyped, prospective study of scan-negative CES supports a model in which acute pain, medication, and mechanisms overlapping with functional neurologic disorders may be relevant.
