Rising suspicion, stable disease: an 8-year analysis of suspected and confirmed cauda equina syndrome.

BACKGROUND CONTEXT: 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.

PURPOSE: To evaluate temporal trends in suspected CES referrals over 8 years within a regional tertiary spinal service, using multidisciplinary team (MDT) clinico-radiological consensus as the diagnostic gold standard.

STUDY DESIGN/

SETTING

Retrospective observational cohort study at a regional tertiary spinal centre.

PATIENT SAMPLE: Consecutive adult patients referred with suspected CES between 2016 and 2023.

OUTCOME MEASURES: Confirmed CES (CES+) based on MDT consensus; referral volume, red-flag prevalence, objective bladder metrics, and diagnostic yield.

METHODS

Temporal trends were analysed across the study period. Objective urinary retention was defined as postvoid residual (PVR) >200 mL or catheterisation at presentation.

RESULTS

A total of 1,188 referrals were included, of which 163 (13.7%) were confirmed as CES+. Referral volume increased significantly over time (p<.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 (prevoid>500 mL and PVR>200 mL) declined significantly (p=.0165 and p=.0238, respectively); however, composite objective urinary retention demonstrated no significant linear trend (p=.120). Among confirmed CES+ cases, symptom profiles varied nondirectionally across years, and objective urinary retention remained a common feature.

CONCLUSIONS

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.