Intracranial intraoperative radiotherapy (IORT): evaluation of electrocorticography and peri-operative seizure risk.

BACKGROUND: Intra-operative radiotherapy (IORT) for brain metastases (BMs) and primary brain tumors has emerged as an adjuvant radiation modality that allows for consolidation of care into a single anesthetic episode with surgical resection. Yet, there is a paucity of data regarding the impact that IORT may have on peri-operative and long-term seizure risk. METHODS: A retrospective analysis of patients receiving IORT during tumor resection was performed via registry including data regarding peri-operative anti-seizure medications and anesthetic agents. Intra-operative neuromonitoring was performed using electrocorticography (ECoG) captured before-, during-, and after-IORT then analyzed for evidence of seizure or significant baseline changes. Kaplan-Meir estimations were used for overall survival analysis relative to documented clinical seizure incidence post-IORT. RESULTS: Of the 24 consecutive patients treated with IORT during tumor resection included, 18 (75%) patients were diagnosed with BMs while 6 (25%) had newly-diagnosed glioblastoma. Mean and median survival times were 487 and 372 days, respectively. Clinical seizures occurred in 3 patients post-IORT, 2 BMs patients within 9 months and 1 glioblastoma patient at 14 months. IORT time represented 9.5% of anesthetic time. ECoG recordings were available for 5 patients (4 BMs; 1 glioblastoma), with mean recording durations of 13% of the total anesthetic time and no evidence of high-frequency oscillations or seizure activity. CONCLUSIONS: IORT is an option for delivery of definitive radiation in surgically resected brain tumors without increasing the peri-operative or long-term risk of seizure. ECoG data during the delivery of radiation fail to demonstrate any electrophysiological changes in response to ionizing radiation.

Determinants of postictal agitation and recovery after tonic-clonic seizures in generalized and focal epilepsy.

OBJECTIVE: The postictal state after bilateral tonic-clonic seizures is often prolonged and can have significant impact on a patient's quality of life. Considerable variability exists in the magnitude of postictal agitation and in the speed of recovery, the determinants of which are not well understood. We studied postictal behavior after tonic-clonic seizures in various epilepsy localizations, focusing on postictal agitation and time to responsiveness. METHODS: We retrospectively identified 15 adult patients each with idiopathic generalized, left temporal lobe, right temporal lobe and frontal lobe epilepsy. Localization in focal epilepsy was validated by good outcome after resective surgery at one-year of follow-up. The first tonic-clonic seizure with reliable video and EEG for each patient was analyzed by two reviewers, one of whom was blinded to clinical data. Clinical, ictal and postictal variables were collected for each patient and analyzed. Postictal agitation was classified as mild and marked. RESULTS: We reviewed 60 tonic-clonic seizures, 15 in each of four patient groups. Postictal agitation was observed in 14 patients (23.3%; marked in one and mild in 13). Postictal agitation was most common in patients with left temporal (seven patients) and least common in idiopathic generalized epilepsy (one patient) groups (p=0.035). Based on subgroup analysis (n=28), time to responsiveness was 6.6 minutes for frontal, 7.2 minutes for generalized, 10 minutes for right temporal and 15.7 minutes for the left temporal groups (p<0.05 for frontal vs. left temporal, generalized vs. left temporal). Time to responsiveness was longer in patients with agitation than without (13.9 minutes vs. 7.7 minutes; p=0.048). Patient ictal and postictal characteristics demonstrated no relationship to agitation or latency to postictal recovery. SIGNIFICANCE: To mitigate harm, patients must be monitored carefully after tonic-clonic seizures, especially patients with left temporal lobe epilepsy. Studies evaluating medical and behavioral interventions to promote postictal recovery are needed.

Drug-resistant high grade glioma-related epilepsy surgery for focal motor status epilepticus localized by CT-PET imaging.

Tumor-related epilepsy is a frequent complication of glioblastoma with seizures often representing the first manifestation of the malignancy. Though tumor resection is associated with improved seizure control, extensive surgery is not always feasible if eloquent cortex is involved in seizure generation and early propagation. We describe a case of a patient with glioblastoma with drug-resistant focal status epilepticus where fluorodeoxyglucose positron emission tomography imaging was successfully used to localize the seizure-onset and optimize tumor resection. This led to successful resection of hypermetabolic tumor tissue and resolution of focal status epilepticus without damage to eloquent cortex.

Post-ictal Modulation of Baroreflex Sensitivity in Patients With Intractable Epilepsy.

Objective: Seizure-related autonomic dysregulation occurs in epilepsy patients and may contribute to Sudden Unexpected Death in Epilepsy (SUDEP). We tested how different types of seizures affect baroreflex sensitivity (BRS) and heart rate variability (HRV). We hypothesized that BRS and HRV would be reduced after bilateral convulsive seizures (BCS). Methods: We recorded blood pressure (BP), electrocardiogram (ECG) and oxygen saturation continuously in patients (n = 18) with intractable epilepsy undergoing video-EEG monitoring. A total of 23 seizures, either focal seizures (FS, n = 14) or BCS (n = 9), were analyzed from these patients. We used 5 different HRV measurements in both the time and frequency domains to study HRV in pre- and post-ictal states. We used the average frequency domain gain, computed as the average of the magnitude ratio between the systolic BP (BPsys) and the RR-interval time series, in the low-frequency (LF) band as frequency domain index of BRS in addition to the instantaneous slope between systolic BP and RR-interval satisfying spontaneous BRS criteria as a time domain index of BRS. Results: Overall, the post-ictal modulation of HRV varied across the subjects but not specifically by the type of seizures. Comparing pre- to post-ictal epochs, the LF power of BRS decreased in 8 of 9 seizures for patients with BCS; whereas following 12 of 14 FS, BRS increased. Similarly, spontaneous BRS decreased following 7 of 9 BCS. The presence or absence of oxygen desaturation was not consistent with the changes in BRS following seizures, and the HRV does not appear to be correlated with the BRS changes. These data suggest that a transient decrease in BRS and temporary loss of cardiovascular homeostatic control can follow BCS but is unlikely following FS. Significance: These findings indicate significant post-ictal autonomic dysregulation in patients with epilepsy following BCS. Further, reduced BRS following BCS, if confirmed in future studies on SUDEP cases, may indicate one quantifiable risk marker of SUDEP.