Temporal Trends in Hippocampal Sclerosis Surgery: An Observational Study From a Tertiary Epilepsy Centre

Temporal lobe epilepsy with hippocampal sclerosis (HS) is a surgically remediable syndrome. We determined temporal trends in the prevalence of hippocampal sclerosis surgeries and related factors.

We analysed a prospective cohort of adults who underwent epilepsy surgery at the NHNN, London, between 1990 and 2019. HS group was compared with other pathologies. Demographics, surgical trends for HS and associations with sex, age, prior neurological insults and febrile seizures were analysed. Temporal trends were assessed by one-way or Welch ANOVA, with post hoc analysis. Surgery latency over three decades was evaluated with the Kruskal-Wallis H test, using Dunn's procedure for pairwise comparisons. Chi-squared analyses examined associations with sex, age at operation, febrile seizures, and between resection side and handedness.

Of 1069 people operated, 586 had hippocampal sclerosis. After increasing, surgeries declined in the last decade (from 322 to 131), as did the number of people with hippocampal sclerosis and a history of childhood febrile seizures (from 87 to 23). The median interval from epilepsy onset to surgery increased from 22 to 24 and 27 years over each decade. Female sex and febrile seizures were associated with pathology (HS vs. non-HS) but not age at surgery, previous neurological insults, or the resection side and handedness.

Our study confirms the decline in hippocampal surgeries. This trend may be due to changes in the syndrome's natural history, possibly from improved paediatric care, and an increase in complex cases. The impact of delayed referrals, surgical risk fears and newer anti-seizure medications remains unclear.