Demographics of Cauda Equina Syndrome: A Population-Based Incidence Study.

INTRODUCTION: Cauda equina syndrome (CES) has significant medical, social, and legal consequences. Understanding the number of people presenting with CES and their demographic features is essential for planning healthcare services to ensure timely and appropriate management. We aimed to establish the incidence of CES in a single country and stratify incidence by age, gender, and socioeconomic status. As no consensus clinical definition of CES exists, we compared incidence using different diagnostic criteria. METHODS: All patients presenting with radiological compression of the cauda equina due to degenerative disc disease and clinical CES requiring emergency surgical decompression during a 1-year period were identified at all centres performing emergency spinal surgery across Scotland. Initial patient identification occurred during the emergency hospital admission, and case ascertainment was checked using ICD-10 diagnostic coding. Clinical information was reviewed, and incidence rates for all demographic and clinical groups were calculated. RESULTS: We identified 149 patients with CES in 1 year from a total population of 5.4 million, giving a crude incidence of 2.7 (95% CI: 2.3-3.2) per 100,000 per year. CES occurred more commonly in females and in the 30-49 years age range, with an incidence per year of 7.2 (95% CI: 4.7-10.6) per 100,000 females age 30-39. There was no association between CES and socioeconomic status. CES requiring catheterization had an incidence of 1.1 (95% CI: 0.8-1.5) per 100,000 adults per year. The use of ICD-10 codes alone to identify cases gave much higher incidence rates, but was inaccurate, with 55% (117/211) of patients with a new ICD-10 code for CES found not to have CES on clinical notes review. CONCLUSION: CES occurred more commonly in females and in those between 30 and 49 years and had no association with socioeconomic status. The incidence of CES in Scotland is at least four times higher than previous European estimates of 0.3-0.6 per 100,000 population per year. Incidence varies with clinical diagnostic criteria. To enable comparison of rates of CES across populations, we recommend using standardized clinical and radiological criteria and standardization for population structure.