Abstracts

There has been extensive discussion about whether hippocampal sclerosis (HS) is the best prognostic factor concerning outcome measurements after surgical treatment of mesial temporal lobe epilepsy (TLE). HS is characterised by pronounced cell loss and gliosis in various regions of the hippocampal formation. On the other hand there are temporal lobe epilepsies with no HS. Due to the grading system as proposed by A. R. Wyler et al. (1992) tissue changes graded as Wyler 0 up to Wyler 2 are considered to be non-HS, whereas changes graded as Wyler 3 and 4 are grouped as HS. We were interested in how far outcome results would differ in regard to the above mentioned grouping between these two groups in our TLE patients (pts) treated surgically (temporal lobe resection/TLR). We identified 164 pts who underwent TLR at our centre between December 1996 and December 2003 (7 years). The group comprised of 76 female and 88 male pts of a mean age of 35,2 years at the time of operation (Range: 4 [ndash] 68 yrs.). 77 patients underwent a TLR on the right side and 87 on the left side. We excluded for further analysis all pts with insufficient follow-up of less then 6 months or missing histopathological data. We were left with 159 pts which we subdivided according to the postoperative histological results of the resected specimen into HS (Wyler 3[deg] and 4[deg]), Non-HS (Wyler 0[deg],1[deg] [amp] 2[deg]), Neoplasias, Dysplasias, and others (e.g. traumatic lesions). We evaluated outcome results following the classification proposed by J. Engel jr.. We also worked up electroclinical and history differences in these groups. Of the 159 pts in whom we were able to obtain all the target data 90 were classified as HS following the histopathological results. The specimen of 14 pts was graded as Wyler 0[deg], 1[deg] or 2[deg] (non-HS). 55 pts belonged to the other groups.
Outcome results showed that seizure freedom (Engel class1) was achieved in 74 of the 90 HS-pts [equals 82%], in 9 of the 14 pts graded as non-HS [equals 64%], in 15 out of 19 pts belonging to the Neoplastic lesion group [equals 79%] and in 3 pts of 6 pts with Dysplasias [equals 50%] and 19 pts of 30 pts in the [quot]others[quot] group [equals 63%]. It was astonishing to find that all 9 pts in the non-HS-group became completely seizure free (also without auras) according to Engel[rsquo]s class: 1A. Even though significantly more patients with a histologically proven HS became completely seizure free in the long run, we found a high degree of excellent outcome (completely seizure free) in the patient group with a non-HS finding in the histopathology. This shows that even slight hippocampal changes (graded as non-HS type) seems to be a relatively important prognostic factor for this group of epilepsies.