Negative MRI and a seizure onset zone close to eloquent areas in FCD type II: Application of MRg-LiTT after a SEEG re-evaluation in pediatric patients with a previous failed surgery.

OBJECTIVE: Negative MRI and an epileptogenic zone (EZ) adjacent to eloquent areas are two main issues that can be encountered during pre-surgical evaluation for epilepsy surgery. Focal Cortical Dysplasia type II (FCD type II) is the most common aetiology underlying a negative MRI. The objective of this study is to present three cases of pediatric patients exhibiting negative MRI and a seizure onset zone close to eloquent areas, who previously underwent traditional open surgery or SEEG-guided radiofrequency thermocoagulations (RF-TC). After seizure seizure recrudescence, pre-surgical SEEG was re-evaluated and Magnetic Resonance-guided laser interstitial thermal therapy (MRg-LiTT) was performed. We discuss the SEEG patterns, the planning of laser probes trajectories and the outcomes one year after the procedure. METHODS: Pediatric patients who underwent SEEG followed by MRg-LiTT for drug-resistant epilepsy associated with FCD type II at our Centre were included. Pre-surgical videoEEG (vEEG), stereoEEG (sEEG), and MRI were reviewed. Post-procedure clinical outcome (measured by Engel score) and complications rates were evaluated. RESULTS: Three patients underwent 3 MRg-LiTT procedures from January 2022 to June 2022. Epileptogenic zone was previously studied via SEEG in all the patients. All the three patients pre-surgical MRI was deemed negative. Mean age at seizure onset was 47 months (21-96 months), mean age at MRg-LiTT was 12 years (10 years 10 months - 12 years 9 months). Engel class Ia outcome was achieved in patients #2 and #3, Engel class Ib in patient #1. Mean follow-up length was of 17 months (13 months - 20 months). Complications occurred in one patient (patient #2, extradural hematoma). CONCLUSIONS: The combined use of SEEG and MRg-LiTT in complex cases can lead to good outcomes both as a rescue therapy after failed surgery, but also as an alternative to open surgery after a successful SEEG-guided Radiofrequency Thermocoagulation (RF-TC). Specific SEEG patterns and a previous good outcome from RF-TC can be predictors of a favourable outcome.

Stereo-EEG tailored resection in a child with presumed perinatal post-stroke epilepsy: The complex organization of epileptogenic zone.

Introduction: Only a few studies have focused on tailored resection in post-stroke epilepsy, in which hemispherectomy and hemispherotomy are the most recognized treatments. Case description: We describe the case of a patient with drug-resistant, presumed perinatal, post-stroke epilepsy and moderate right hemiparesis. The seizures were stereotyped, both spontaneous and induced by sudden noises and somatosensory stimuli. Considering the discordant anatomic-electro-clinical data - left perisylvian malacic lesion with electrical onset over the left mesial fronto-central leads - and the patient's functional preservation, SEEG was performed. SEEG revealed sub-continuous abnormalities in the perilesional regions. Several seizures were recorded, with onset over the premotor area, rapidly involving the motor and insular-opercular regions. We decided for a combined surgical approach, SEEG-guided radiofrequency thermocoagulation, on the fronto-mesial structure but also on the central operculum, followed by resective surgery including only the fronto-mesial structures. Discussion and conclusion: The SEEG allowed to localize the epileptogenic zone far away from the anatomical lesion but connected to part of it. A combined surgical approach tailored on SEEG results allowed a good outcome (Engel Ib) without additional deficits.

Clinical characterization of status epilepticus in childhood: a retrospective study in 124 patients.

PURPOSE: The aim of this study is to describe demographic data, semiology and etiology in a pediatric population with status epilepticus (SE) and refractory SE (RSE). METHOD: We retrospectively reviewed patients with the following inclusion criteria: i) age between two months and eighteen years; ii) SE diagnosis; iii) admission from January 2001 to December 2016; iv) available clinical data. RESULTS: We enrolled 124 patients. Mean and median age was 4.6 ± 4.2 years and 3.3 [1.2-7.5] years respectively. SE had a "de novo" onset in 66.9%. Focal convulsive-SE was the most common semiology (50.8%) whilst generalised (32.3%) and nonconvulsive-SE (NCSE) (16.9%) were less represented. Some etiologies showed a different age distribution: febrile in youngest age (p = 0.002, phi 0.3) and idiopathic-cryptogenic in older children (p = 0.016, phi 0.2). A statistical significance correlation was detected between semiology and etiology (p < 0.001, Cramer's V 0.4), chemotherapy and NCSE (n = 6/21 vs 3/103, p < 0.001) as well as PRES and NCSE (n = 7/21 vs 5/103, p < 0.001). Only 17.7% had a RSE. No correlation was found in demographic and clinical data, but NCSE, acute and idiopathic-cryptogenic etiologies were more frequently associated to RSE. Encephalitis was the most common diagnosis in acute etiologies whereas unknown epilepsy in idiopathic-cryptogenic group. CONCLUSION: Most of our findings were previously described however we found a significant role of non-antiepileptic treatments (chemotherapy-dialysis) and comorbidity (PRES) determining acute etiology and NCSE. Acute (mostly encephalitis), idiopathic-cryptogenic (mainly unknown-epilepsy) and NCSE were frequently detected in RSE. In the above mentioned conditions a high level of suspicion was recommended.

Computerized local anesthetic delivery vs. traditional syringe technique. Subjective pain response.

A study was designed to determine if there are changes in the perception of pain when the flow rate and pressure of an injected anesthetic are precisely controlled. Fifty dentists were given contralateral palatal injections. One side was injected with the Wand injector, a new delivery system that uses a microprocessor and an electric motor to precisely regulate flow rate during administration. The control side was injected using a standard manual syringe, in which flow rate and pressure are operator-dependent and cannot be controlled accurately. The subjects used two subjective scales to describe their perceived pain experience. When their responses were analyzed the Wand injector was found to be two- to three-times less painful than the manual injection. The results were statistically significant (p < .001). The authors conclude that there is an optimal flow rate of anesthetic solution at which the perception of pain during an injection is minimized.

Fast-atom bombardment mass spectrometry and metastable-ion studies for the characterization of isomeric fluorosugars.

Characterization of stereoisomeric 3,4-dideoxy-3-fluoro-hexoses has been carried out using fast-atom bombardment. Diagnostic fragments were observed in the daughter-ion spectra of the [M - H]- and [M + H]+ ionic species. Notable differences were also observed in the relative abundances of ionic species corresponding to [M - H]-, [M - H - HF]- and [C11H11O2]- ions.

Mass spectrometric approaches in structural characterization of cephalosporins.

The mass spectrometric behaviour of five structurally different cephalosporins has been studied in detail by means of different ionization/desorption methods (electron impact, fast atom bombardment, desorption chemical ionization, laser-induced vaporization) and metastable ion studies (linked scans and mass-analysed ion kinetic energy spectrometry). The best results were obtained by fast atom bombardment mass spectrometry, leading to both molecular ions and fragment ions diagnostic for structural identification.