John P. Girvin

Cardiovascular effects of human insular cortex stimulation

Recent investigations indicate a site of cardiac representation within the left insular cortex of the rat. Moreover, the results of lesion studies suggest left-sided insular dominance for sympathetic cardiovascular effects. It is unclear whether similar representation exists within the human insular cortex. Five epileptic patients underwent intraoperative insular stimulation prior to temporal lobectomy for seizure control. On stimulation of the left insular cortex, bradycardia and depressor responses were more frequently produced than tachycardia and pressor effects (p < 0.005). The converse applied for the right insular cortex. We believe this to be the first demonstration of cardiovascular changes elicitable during insular stimulation in humans, and of lateralization of such responses for a cortical site. In humans, unlike the rat, there appears to be right-sided dominance for sympathetic effects. These findings may be of relevance in predicting the autonomie effects of stroke in humans and in the explanation of sudden unexpected epileptic death.

Propofol sedation during awake craniotomy for seizures: patient-controlled administration versus neurolept analgesia.

This prospective study evaluated the safety and efficacy of patient-controlled sedation (PCS) using propofol during awake seizure surgery performed under bupivacaine scalp blocks. Thirty-seven patients were randomized to receive either propofol PCS combined with a basal infusion of propofol (n = 20) or neurolept analgesia using an initial bolus dose of fentanyl and droperidol followed by a fentanyl infusion (n = 17). Both groups received supplemental fentanyl and dimenhydrinate for intraoperative pain and nausea, respectively. Comparisons were made between groups for sedation, memory, and cognitive function, patient satisfaction, and incidence of complications. Levels of intraoperative sedation and patient satisfaction were similar between groups. Memory and cognitive function were well preserved in both groups. The incidence of transient episodes of ventilatory rate depression (<8 bpm) was more frequent among the propofol patients (5 vs 0, P = 0.04), particularly after supplemental doses of opioid. Intraoperative seizures were more common among the neurolept patients (7 vs 0, P = 0.002). PCS using propofol represents an effective alternative to neurolept analgesia during awake seizure surgery performed in a monitored care environment. (Anesth Analg 1997;84:1285-91)

Significance of Spikes at Temporal Lobe Electrocorticography

Summary: Among 87 consecutive patients operated on under local anesthesia, few aspects of pre‐ and posttemporal lobe resection electrocorticograms (ECoG) yielded prognostic data. Preresection spikes were most common in the hippocampus, followed in order of frequency by the anterior temporal convexity and the inferior temporal surface. Moderately frequent (>10 spikes/100 s) preresection spikes appeared beyond the subsequent resection line in the posterior temporal region in 16 of 87 (18%) and in orbital frontal cortex in 12 of 87 (14%). Although many hippocampus spikes portended a favorable outcome and rare spikes an unfavorable one, preresection spike quantity otherwise failed to distinguish outcome groups. Absolute quantity of postresection spikes and change from preresection quantity in any region did not correlate with outcome except for the insula, where relatively abundant spikes portended favorable outcomes. Postresection electrographic seizures were rare but occurred equally in all outcome groups. No significant change in spike incidence occurred between the first and last 10‐min epoch of the 30‐min postresection recording.

Propofol sedation during awake craniotomy for seizures: electrocorticographic and epileptogenic effects.

This prospective study evaluated the effects of propofol sedation on the incidence of intraoperative seizures and the adequacy of electrocorticographic (ECoG) recordings during awake craniotomy performed for the management of refractory epilepsy.Thirty patients scheduled for temporal or frontal lobectomy for epilepsy under bupivacaine scalp block were randomized to receive patient-controlled propofol sedation (PCS) combined with a basal infusion of propofol (n = 15) or neurolept analgesia using an initial bolus dose of fentanyl (0.7 micro g/kg) and droperidol (0.04 mg/kg) followed by a fentanyl infusion (n = 15). Propofol administration was suspended 15 min before ECoG recording in the PCS group. The occurrence of inappropriate intraoperative seizures was noted and, based on blind review, the adequacy of ECoG recordings was compared. A higher incidence of intraoperative seizures was noted among the neurolept patients (6 vs 0, P = 0.008). Intraoperatively, ECoG recordings were adequate to proceed with resection in both groups. Evidence of low spike activity on ECoG did not correlate with the type of sedation administered. Higher frequency background ECoG activity was noted among patients who received propofol, but this did not interfere with ECoG interpretation. The use of propofol sedation does not appear to interfere with ECoG during epilepsy surgery, provided administration is suspended at least 15 min before recording. (Anesth Analg 1997;84:1280-4)

Isolation and culture of cells derived from human cerebral microvessels

SummaryMicrovessels were isolated from non-neoplastic human cerebral cortical fragments resected for treatment of intractable seizure disorder. The microvessels were incubated in modified Lewis medium with 20 or 30% fetal bovine serum. Within 1–2 weeks, two cell populations emerged from the isolates. One type of cells had polygonal morphology, showed density-dependent contact inhibition at confluence in vitro, showed lectin-binding characteristics of endothelium (but only moderate positivity for factor VIII antigen), demonstrated induction of γ-glutamyl trans-peptidase when exposed to astrocyte-conditioned media, and responded to insulin by a pronounced increase in DNA synthesis. The other variety of cells grew in vitro more slowly in irregular strands separated by clear zones, showed ultrastructural features of smooth muscle, and isoelectric focusing of cell proteins revealed the presence of smooth-musclespecific α-isoactin. Both types of cells could be serially subcultured. The ability to isolate and grow the two cell types, tentatively identified as human cerebral microvascular endothelium and smooth muscle, may facilitate studies of human blood-brain barrier function as well as the pathogenesis of cerebral microangiopathies unique to the human brain.

An economic evaluation of surgery for temporal lobe epilepsy

Abstract We wished to determine whether surgery in adults with difficult to control temporal lobe epilepsy (TLE) is more effective and less costly than medical therapy. We evaluated the costs and consequences of surgical versus medical treatment of TLE, using decision-analysis modeling and an intention-to-treat approach. Data on outcome probabilities and resource utilization were obtained from critical appraisal of the literature, local experience, a panel of experts, and community patient survey. Surgically treating 100 patients for 35 years results in 57 seizure-free patients and a cost of

Effectiveness of temporal lobectomy measured by yearly follow-up and multivariate analysis

8,117,911. Medically treating 100 patients results in 12 seizure-free patients and a cost of

Temporal lobectomy for intractable epilepsy in patients over age 45 years

10,741,425. Surgery required a larger initial expenditure than medical treatment (

Spreading depression of Lea˜o in rodent and human cortex

2,775,640 vs.

Trigeminal Neuralgia: A Comparison of the Results of Percutaneous Rhizotomy and Microvascular Decompression

856,970), but cost-time curves intersect at 8.5 years and surgery remained cheaper thereafter. Results were unchanged by extensive sensitivity analyses. The major determinant of surgical dominance is its greater effectiveness (seizure-free rate) as compared with medical treatment. Surgery remained less costly, with concurrent effectiveness rates >41 and