André Turmel

Electrical stimulation of the human brain in epilepsy.

Summary: The concordance between the epileptogenic area as determined by intracranially recorded spontaneous seizure onset and that determined by electrically induced auras or seizures in 126 patients with medically intractable epilepsy was studied. Four to 11 multicontact depth electrodes were chronically implanted in patients as part of a preoperative investigation procedure. Local‐ ization of the epileptic area was obtained from the record‐ ing of three spontaneous seizures and from stimulation data including self‐reported auras, seizures, and intracra‐ nial EEG afterdischarges recorded during an incremental stimulation sequence at all cortical pairs of contacts. Positive responses to stimulation were obtained in 63% of patients. Concordance between spontaneous and induced auras or seizures was >90% with single unilateral foci and less with multiple foci. Stimulation data reliably predicted the resection area in unilateral and bilateral temporal foci but not in other locations. Afterdischarge thresholds were not reliable predictors of the spontaneous seizure focus. The intracranial stimulation procedure used appears to provide useful confirmatory and complementary localiz‐ ing information in relation to that obtained from sponta‐ neous seizures.

Sensitization of rat forebrain neurons to serotonin by adinazolam, an antidepressant triazolobenzodiazepine.

Adinazolam , a triazolobenzodiazepine , has been reported to be an effective antidepressant treatment in major depression. In the present study, a 14-day (but not a five-day) treatment with adinazolam enhanced the responsiveness of rat hippocampal pyramidal neurons to microiontophoretically applied 5-HT but not to NE. A 14-day treatment with diazepam failed to induce sensitization to either 5-HT or NE. Acute intravenous administration of adinazolam did not modify dorsal raphe 5-HT neuron firing rate. It is proposed that the antidepressant activity of adinazolam might be mediated by a heightened 5-HT neurotransmission.

Spinal man after declaration of brain death.

Complex spinal automatism in a patient who was declared brain dead is described. These movements tend to appear once cerebrospinal shock has abated. We postulate that these manifestations are a reflection of the physiological potential of the isolated spinal cord. These spinal movements should be included in the revised guidelines for the determination of cerebral death.

Predicting success of endoscopic third ventriculostomy: validation of the ETV Success Score in a mixed population of adult and pediatric patients

OBJECTnEndoscopic third ventriculostomy (ETV) has become the first line of treatment in obstructive hydrocephalus. The Toronto group (Kulkarni et al.) developed the ETV Success Score (ETVSS) to predict the clinical response following ETV based on age, previous shunt, and cause of hydrocephalus in a pediatric population. However, the use of the ETVSS has not been validated for a population comprising adults. The objective of this study was to validate the ETVSS in a closed-skull population, including patients 2 years of age and older.nnnMETHODSnIn this retrospective observational study, medical charts of all consecutive cases of ETV performed in two university hospitals were reviewed. The primary outcome, the success of ETV, was defined as the absence of reoperation or death attributable to hydrocephalus at 6 months. The ETVSS was calculated for all patients. Discriminative properties along with calibration of the ETVSS were established for the study population. The secondary outcome is the reoperation-free survival.nnnRESULTSnThis study included 168 primary ETVs. The mean age was 40 years (range 3-85 years). ETV was successful at 6 months in 126 patients (75%) compared with a mean ETVSS of 82.4%. The area under the receiver operating characteristic curve was 0.61, revealing insufficient discrimination from the ETVSS in this population. In contrast, calibration of the ETVSS was excellent (calibration slope = 1.01), although the expected low numbers were obtained for scores < 70. Decision curve analyses demonstrate that ETVSS is marginally beneficial in clinical decision-making, a reduction of 4 and 2 avoidable ETVs per 100 cases if the threshold used on the ETVSS is set at 70 and 60, respectively. However, the use of the ETVSS showed inferior net benefit when compared with the strategy of not recommending ETV at all as a surgical option for thresholds set at 80 and 90. In this cohort, neither age nor previous shunt were significantly associated with unsuccessful ETV. However, better outcomes were achieved in patients with aqueductal stenosis, tectal compressions, and other tumor-associated hydrocephalus than in cases secondary to myelomeningocele, infection, or hemorrhage (p = 0.03).nnnCONCLUSIONSnThe ETVSS did not show adequate discrimination but demonstrated excellent calibration in this population of patients 2 years and older. According to decision-curve analyses, the ETVSS is marginally useful in clinical scenarios in which 60% or 70% success rates are the thresholds for preferring ETV to CSF shunt. Previous history of CSF shunt and age were not associated with worse outcomes, whereas posthemorrhagic and postinfectious causes of the hydrocephalus were significantly associated with reduced success rates following ETV.

Relative localizing value of common tests used in the preoperative investigation of epileptic patients

We have compared the relative localizing value of common tests in the presurgical evaluation of epilepsy in 73 patients with depth electrode (SEEG) confirmed epileptogenic foci and excellent surgical outcome. We found the tests of abnormality (CT, amytal, neuropsychology) to be frequently non-informative and often discordant with SEEG. The EEG was concordant with the SEEG in 38% of cases and provided lateralization in 78%. EEG was less localizing than ictal behavior in frontals but not in temporals. The need for SEEG is rather evident in these results but could become attenuated by the development of the localizing power of scalp EEG.

Internal Audit of Compliance with a Perioperative Checklist in a Tertiary Care Neurosurgical Unit.

BACKGROUNDnIn 1999, the Institute of Medicine reported that, in the United States, 44,000 to 98,000 people die annually as a result of avoidable medical errors. Among the many initiatives undertaken to stem avoidable surgical errors, the World Health Organization (WHO) Surgical Safety Checklist has certainly been one of the most successful. Many surgical units have implemented adapted versions of the WHO Surgical Safety Checklist, audited their performance and discussed issues relating to the implementation process. However, such literature is still lacking in neurosurgery.nnnMETHODSnA prospective observational study of 171 neurosurgical cases was conducted over an 8-week period. An independent observer assessed compliance with and completeness of the three steps in the perioperative checklist: Sign-in, Time-out and Sign-out. Factors that may reduce compliance were also analyzed.nnnRESULTSnCompliance with the Sign-in, Time-out and Sign-out steps was 82%, 99% and 93% respectively. On average, 92% of the Time-out elements were verified. The emergent nature of a surgery was the only factor that caused a statistically significant reduction in compliance with the checklist. Overall compliance diminished during the observation period.nnnCONCLUSIONnIn this internal audit study, compliance with the preoperative checklist reached a satisfactory level. Further work is still needed, however, on some aspects of our surgical strategy, namely, a relatively low compliance rate with the Sign-in process was recorded and emergent cases were associated with decreased performance.