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Reliability of patterns of hippocampal sclerosis as predictors of postsurgical outcome
Author(s) -
Thom Maria,
Liagkouras Ioannis,
Elliot Kathryn J.,
Martinian Lillian,
Harkness William,
McEvoy Andrew,
Caboclo Luis O,
Sisodiya Sanjay M.
Publication year - 2010
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1167.2010.02681.x
Subject(s) - hippocampal sclerosis , temporal lobe , epilepsy , hippocampal formation , medicine , epilepsy surgery , pathology , psychology , neuroscience
Summary Purpose: Around one‐third of patients undergoing temporal lobe surgery for the treatment of intractable temporal lobe epilepsy with hippocampal sclerosis (HS) fail to become seizure‐free. Identifying reliable predictors of poor surgical outcome would be helpful in management. Atypical patterns of HS may be associated with poorer outcomes. Our aim was to identify atypical HS cases from a large surgical series and to correlate pathology with clinical and outcome data. Methods: Quantitative neuropathologic evaluation on 165 hippocampal surgical specimens and 21 control hippocampi was carried out on NeuN‐stained sections. Neuronal densities (NDs) were measured in CA4, CA3, CA2, and CA1 subfields. The severity of granule cell dispersion (GCD) was assessed. Results: Comparison with control ND values identified the following patterns based on the severity and distribution of neuronal loss: classical HS (CHS; n = 60) and total HS (THS; n = 39). Atypical patterns were present in 30% of cases, including end‐folium sclerosis (EFS; n = 5), CA1 predominant pattern (CA1p; n = 9), and indeterminate HS (IHS, n = 35). No HS was noted in 17 cases. Poorest outcomes were noted for no‐HS, and CA1p groups with 33–44% International League Against Epilepsy (ILAE) class I at up to 2 years follow‐up compared to 69% for CHS (p < 0.05). GCD associated with HS type (p < 0.01), but not with outcome. Conclusions: These findings support the identification and delineation of atypical patterns of HS using quantitative methods. Atypical patterns may represent distinct clinicopathologic subtypes and may have predictive value following epilepsy surgery.