Rising Suspicion, Stable Disease: An Eight-Year Analysis of Suspected and Confirmed Cauda Equina Syndrome.

Abstract

Suspected cauda equina syndrome (CES) referral pathways are designed to maximise sensitivity, often prompting urgent MRI based on single red-flag features. Rising referral volumes have raised concern that pathway-driven behaviour may not reflect true disease incidence. Longitudinal analyses anchored to robust diagnostic adjudication remain limited. To evaluate temporal trends in suspected CES referrals over eight years within a regional tertiary spinal service, using multidisciplinary team (MDT) clinico-radiological consensus as the diagnostic gold standard. Retrospective observational cohort study at a regional tertiary spinal centre. Consecutive adult patients referred with suspected CES between 2016 and 2023. Confirmed CES (CES+) based on MDT consensus; referral volume, red-flag prevalence, objective bladder metrics, and diagnostic yield. Temporal trends were analysed across the study period. Objective urinary retention was defined as post-void residual (PVR) >200 mL or catheterisation at presentation. A total of 1,188 referrals were included, of which 163 (13.7%) were confirmed as CES+. Referral volume increased significantly over time (p<0.001) with substantial inter-annual variability, whereas confirmed CES incidence and demographic characteristics remained stable. The prevalence of individual red-flag features showed no consistent directional change, and diagnostic yield did not improve over time. Measured bladder volumes (pre-void >500 mL and PVR >200 mL) declined significantly (p=0.0165 and p=0.0238, respectively); however, composite objective urinary retention demonstrated no significant linear trend (p=0.120). Among confirmed CES+ cases, symptom profiles varied non-directionally across years, and objective urinary retention remained a common feature. MDT-confirmed CES demonstrates epidemiologic and phenotypic stability despite substantial fluctuation in suspected referral activity. Referral volume appears highly sensitive to pathway structure and system-level factors and should not be interpreted as a surrogate for disease incidence. Declining bladder volumes do not indicate earlier detection, and CES remains a heterogeneous neurological syndrome not defined by isolated red-flag features.