Devin K. Binder, Paul A. Garcia, Ganesh K. Elangovan and Nicholas M. Barbaro
Prior studies suggest that aura semiology may have localizing value. However, temporal lobe aura characteristics and response to surgery have not been studied in large patient series.
The authors retrospectively analyzed the case records of 182 patients undergoing temporal lobectomy for medically intractable epilepsy at a single institution. They analyzed the frequency and type of auras and seizures preoperatively, and at 3 months and 1 year after temporal lobectomy. Auras were divided into medial semiology (rising epigastric, olfactory/gustatory, experiential, and fear) and lateral semiology (auditory, somatosensory, and visual), or other.
Of 182 patients, 150 were included in this study. The preoperative prevalence of auras was 77%. Multiple types of auras were present in 20% of patients. The most common aura was rising epigastric (26% of all auras). Postoperatively, auras were eliminated in 63% of patients at 3 months and in 64% at 1 year. Seventy-seven patients (51%) were seizure-free and aura-free, 22 (15%) were seizure-free with auras, 26 (17%) had seizures but no auras, and 25 (17%) had seizures with auras. Despite having their auras eliminated, 6.7% of patients continued to have complex partial seizures. Lateral temporal auras were more than twice as likely as medial temporal auras to persist after surgery (p < 0.002).
While the majority of patients in the authors' series became seizure- and aura-free, a significant minority still had persistent auras. Patients with lateral temporal auras appear to be at increased risk for having persistent postoperative auras. The discrepancy between aura and seizure outcomes results in a small group of patients having persistent seizures but losing their auras postoperatively.
Doris D. Wang, Abby E. Deans, A. James Barkovich, Tarik Tihan, Nicholas M. Barbaro, Paul A. Garcia and Edward F. Chang
Focal cortical dysplasia (FCD) represents a spectrum of developmental cortical abnormalities and is one of the most common causes of intractable epilepsy in children and young adults. Outcomes after surgery for FCD are highly variable, and prognosticators of seizure freedom are unclear. In a subset of FCDs, a transmantle sign is observed on imaging that focally spans the entire cerebral mantle from the ventricle to the cortical surface. The aim of this study was to characterize seizure control outcomes and prognostic significance of the transmantle sign in FCD epilepsy.
Fourteen patients with the transmantle sign underwent epilepsy surgery for medically refractory epilepsy. Thirteen patients underwent resective surgery and 1 underwent multiple subpial transections with vagus nerve stimulator placement. Patient demographics, MRI, electroencephalography, intraoperative electrocorticography (ECoG), and pathology were reviewed. The results of this series were compared with those of 114 previously reported patients with FCD without the transmantle sign.
All patients were found to have childhood seizure onset and concordant MRI and ECoG findings. The primary MRI findings associated with transmantle sign included gray-white junction blurring, appearance of cortical thickening, T2 or FLAIR abnormality, and bottom-of-the-sulcus dysplasia. The transmantle sign was usually a focal finding, typically confined to 1 or several gyri with well-circumscribed epileptic tissue. Correlation of the transmantle sign with FCD histopathological subtypes was highly variable. Patients who underwent complete resection of MRI and ECoG abnormalities (12 of 13 patients) became seizure free. When compared with 114 FCD patients without the transmantle sign, patients with the transmantle sign showed significantly improved seizure-free outcomes after complete resections (p = 0.04).
The presence of the transmantle sign in patients with medically refractory partial epilepsy is associated with highly favorable seizure control outcomes after surgical treatment.
Edward F. Chang, Catherine Christie, Joseph E. Sullivan, Paul A. Garcia, Tarik Tihan, Nalin Gupta, Mitchel S. Berger and Nicholas M. Barbaro
Dysembryoplastic neuroepithelial tumors (DNETs) are a subset of relatively rare glioneuronal tumors that typically present with epilepsy during childhood. The authors' aim was to identify factors that predict seizure control following excision.
The authors reviewed the cases of 50 patients who underwent resection of DNETs at the University of California, San Francisco, between 1990 and 2006. Demographic, seizure history, radiographic, and histopathological data were collected and analyzed for statistical association with postoperative seizure control.
Of the 50 patients, 86% presented with intractable epilepsy. The median age at surgery was 21 years (range 4–46 years; 40% were < 18 years old at time of surgery), with a median duration of 8 years from onset of seizures (24% were adult-onset seizures). Fifty-two percent of the cases were associated with adjacent focal cortical dysplasia. Complete resection was achieved in 78% of cases. Intraoperative electrocorticography in 23 patients identified extralesional interictal activity in 16 cases, which led to extended lesionectomy or lobectomy. The remaining patients underwent lesionectomy alone. The median follow-up was 5.6 years, during which time tumor progression occurred after subtotal resection. The proportional estimates of seizure freedom (Engel Class I outcome) were 0.86 at 1 year and 0.85 at 5 years. Seizure freedom was predicted by complete or extended resection (OR 1.68, 95% CI 1.39–2.03; p < 0.0001) and extratemporal location (OR 1.20, 95% CI 1.02–1.42; p = 0.03) on multivariate analysis. Secondary analysis for intraoperative electrocorticography cases demonstrated that seizure outcome was better when extralesional spiking foci were detected (94% seizure free) compared with when they were absent (43% seizure free).
Excision of DNETs and, when present, adjacent dysplastic cortex was highly effective for seizure control. Excellent seizure-free outcomes and tumor control were seen with lesionectomy alone in most cases. Electrocorticography with extended resection was useful for patients with pharmacoresistant epilepsy.