Long-term outcome of epilepsy surgery among 399 patients with nonlesional seizure foci including mesial temporal lobe sclerosis.

OBJECT: The authors reviewed the long-term outcome of focal resection in a large group of patients who had intractable partial nonlesional epilepsy, including mesial temporal lobe sclerosis (MTS), and who were treated consecutively at a single institution. The goal of this study was to evaluate the long-term efficacy of epilepsy surgery and the preoperative factors associated with seizure outcome. METHODS: This retrospective analysis included 399 consecutive patients who underwent epilepsy surgery at Mayo Clinic in Rochester, Minnesota, between 1988 and 1996. The mean age of the patients at surgery was 32 +/- 12 years (range 3-69 years), and the mean age at seizure onset was 12 +/- 11 years (range 0-55 years). There were 214 female (54%) and 185 male (46%) patients. The mean duration of epilepsy was 20 +/- 12 years (range 1-56 years). The preceding values are given as the mean +/- standard deviation. Of the 399 patients, 237 (59%) had a history of complex partial seizures, 119 (30%) had generalized seizures, 26 (6%) had simple partial seizures, and 17 (4%) had experienced a combination of these. Preoperative evaluation included a routine and video-electroencephalography recordings, magnetic resonance imaging of the head according to the seizure protocol, neuropsychological testing, and a sodium amobarbital study. Patients with an undefined epileptogenic focus and discordant preoperative studies underwent an intracranial study. The mean duration of follow up was 6.2 +/- 4.5 years (range 0.6-15.7 years). Seizure outcome was categorized based on the modified Engel classification. Time-to-event analysis was performed using Kaplan-Meier curves and Cox regression models to evaluate the risk factors associated with outcomes. Among these patients, 372 (93%) underwent temporal and 27 (7%) had extratemporal resection of their epileptogenic focus. Histopathological examination of the resected specimens revealed MTS in 113 patients (28%), gliosis in 237 (59%), and normal findings in 49 (12%). Based on the Kaplan-Meier analysis, the probability of an Engel Class I outcome (seizure free, auras, or seizures related only to medication withdrawal) for the overall patient group was 81% (95% confidence interval [CI] 77-85%) at 6 months, 78% (CI 74-82%) at 1 year, 76% (CI 72-80%) at 2 years, 74% (CI 69-78%) at 5 years, and 72% (CI 67-77%) at 10 years postoperatively. The rate of Class I outcomes remained 72% for 73 patients with more than 10 years of follow up. If a patient was in Class I at 1 year postoperatively, the probability of seizure remission at 10 years postoperatively was 92% (95% CI 89-96%); almost all seizures occurred during the 1st year after surgery. Factors predictive of poor outcome from surgery were normal pathological findings in resected tissue (p = 0.038), male sex (p = 0.035), previous surgery (p < 0.001), and an extratemporal origin of seizures (p < 0.001). CONCLUSIONS: The response to epilepsy surgery during the 1st follow-up year is a reliable indicator of the long-term Engel Class I postoperative outcome. This finding may have important implications for patient counseling and postoperative discontinuation of anticonvulsant medications.

Lateralized and focal clinical, EEG, and FLAIR MRI abnormalities in Creutzfeldt-Jakob disease.

OBJECTIVE: Creutzfeldt-Jakob disease (CJD) is a rapidly progressive fatal prion disorder with typical clinical findings of dementia, motor dysfunction, and myoclonus and characteristic electroencephalographic (EEG) findings of bilateral synchronous periodic sharp waves. Advances in neuroimaging capabilities with diffusion-weighted and fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) techniques have shown promise in the non-invasive diagnosis of CJD. This series illustrates the correlation between the lateralized and focal clinical, EEG, and MRI FLAIR sequence abnormalities in 8 patients (7 men and one woman 55-73 years old) with CJD. METHODS: A case series of 8 patients, evaluated at Mayo Clinic, who had a history of rapidly progressive lateralized or focal neurologic dysfunction and laboratory findings consistent with CJD between 1996 and 1999 were identified. EEG, MRI of the head with FLAIR sequence, and cerebrospinal fluid studies were performed in all patients. RESULTS: Mean time to death from symptom onset was 4 months. Symptoms were lateralized to the left hemisphere in 5 patients and to the right hemisphere in two. One patient showed bilateral occipital lobe involvement. In all patients, the EEG showed lateralized or focal periodic sharp waves that colocalized with clinical cerebral dysfunction. FLAIR MRI images revealed increased signal in the cortical ribbon and deep gray matter corresponding to the lateralized clinical and EEG findings in 7 patients. The other patient had bilateral occipital increased signal on FLAIR MRI. CONCLUSIONS: CJD may present with lateralized or focal cortical syndromes with colocalizing EEG and MRI findings. With the appropriate clinical history and laboratory evaluation, the corresponding areas of increased signal on FLAIR MRI provide supportive evidence of the disease. SIGNIFICANCE: CJD can sometimes present with more focal or lateralized clinical findings, and the colocalizing EEG and MRI findings can help make or confirm the diagnosis of CJD.