Bertil Rydenhag

Increased Sympathetic Nervous Activity in Patients With Nontraumatic Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE Activation of the sympathetic nervous system, which leads to elevation of circulating catecholamines, is implicated in the genesis of cerebral vasospasm and cardiac aberrations after subarachnoid hemorrhage. To this juncture, sympathetic nervous testing has relied on indirect methods only. METHODS We used an isotope dilution technique to estimate the magnitude and time course of sympathoadrenal activation in 18 subarachnoid patients. RESULTS Compared with 2 different control groups, the patients with subarachnoid hemorrhage exhibited an approximately 3-fold increase in total-body norepinephrine spillover into plasma within 48 hours after insult (3.2+/-0.3 and 4.2+/-0.7 versus 10.2+/-1.4 nmol/L; P<0.05 versus both). This sympathetic activation persisted throughout the 7- to 10-day examination period and was normalized at the 6-month follow-up visit. CONCLUSIONS The present study has established that massive sympathetic nervous activation occurs in patients after subarachnoid hemorrhage. This overactivation may relate to the well-known cardiac complications described in subarachnoid hemorrhage.

Complications of epilepsy surgery after 654 procedures in Sweden, September 1990-1995 : a multicenter study based on the Swedish National Epilepsy Surgery Register

OBJECTIVETo present the first national multicenter study on complications after epilepsy surgery procedures to include all epilepsy surgery centers in Sweden: Göteborg, Linköping, Lund, Stockholm, Umeå, and Uppsala. METHODSEvery epilepsy surgery procedure in Sweden is reported to the Swedish National Epilepsy Surgery Register. The report includes relevant social and medical items and complications. A complication is defined as minor if it resolves within 3 months and major if it affects activities of daily living and lasts longer than 3 months. Follow-up data are recorded for 2 years after the operation. Intrinsic checkpoints and external revision validate the register data. RESULTSDuring the inclusion period (September 1990–December 1995), 654 surgical procedures were performed (age range, 6 mo–67 yr). Of these, 205 were invasive electrode procedures (182 first investigations and 23 reinvestigations), and 449 were therapeutic procedures (375 first operations and 74 reoperations). After invasive electrode procedures, only minor complications were reported (6.3%). For all 449 therapeutic procedures (including reoperations), minor complications were reported in 8.9% and major complications in 3.1%. Only one major complication was reported in a patient under the age of 35 years. CONCLUSIONThis is the first national multicenter study on complications after epilepsy surgery. It demonstrates that these procedures as performed at six different centers in Sweden are safe, but also that risk is related to age. In patients younger than age 35 years, the risk for a major complication after invasive subdural strip electrode investigation and epilepsy surgery is low.

Intersubject variability in the anterior extent of the optic radiation assessed by tractography.

INTRODUCTION Temporal lobe resection for epilepsy involves a risk of damaging the anterior part of the optic radiation, Meyers loop, causing a contralateral upper quadrant visual field defect. This study aims to assess the intersubject variability in the course of Meyers loop in vivo by diffusion tensor imaging and tractography. METHODS Seven healthy volunteers and two patients with previous temporal lobe resection were recruited. Diffusion tensor imaging and tractography were used to visualize the optic radiation. The distances from the anterior edge of Meyers loop to landmarks in the temporal lobe were calculated. RESULTS In the healthy subjects, the mean distance between the most anterior part of Meyers loop and the temporal pole was 44 mm (range 34-51 mm). Meyers loop did not reach the tip of the temporal horn in any subject. A disruption in Meyers loop could be demonstrated in the patient with quadrantanopia after temporal lobe resection. CONCLUSIONS Meyers loop has a considerable variability in its anterior extent. Tractography may be a useful method to visualize Meyers loop, and assess the risk of a visual field defect, prior to temporal lobe resection.

A standardized neurosurgical/neurointensive therapy directed toward vasogenic edema after severe traumatic brain injury: clinical results

Objective: Analysis of a standardized therapy focusing on prevention and treatment of vasogenic edema in patients suffering severe traumatic brain injury (TBI). Design: A retrospective analysis. Setting: Neurointensive care unit at Sahlgrenska University Hospital, Göteborg, Sweden. Patients: 38 patients with severe TBI were included. The median Glasgow Coma Score was 5 (range 3–8) and median age 27 years (range 5–70 years). Interventions: Measurement of intracranial pressure (ICP). Surgical evacuation of hematomas and contusions. Volume expansion aiming at normovolemia. Sedation with continuous intravenous infusion of low-dose thiopentone and reduction of stress response by clonidine. Normalization of capillary hydrostatic pressure by metoprolol and clonidine. If ICP and cerebral perfusion pressure (CPP) were not stabilized (ICP < 20 mm Hg and CPP > 60 mm Hg), a continuous infusion of dihydroergotamine was added. In 4 patients a craniectomy was performed. Results: Of the 38 patients, 27 (71 %) survived with good recovery or moderate disability, 5 (13 %) survived with severe disability, 1 (3 %) remained in a vegetative state, and 5 (13 %) died. The mortality due to intracranial hypertension was 11 % (4 patients). Conclusion: A therapy focusing on treatment of the assumed vasogenic edema in combination with aggressive neurosurgery resulted in an outcome as good as the best previously reported.

Surgical treatment of epilepsy ‐ clinical, radiological and histopathological findings in 139 children and adults

The present study relates clinical and radiological data to histopathological diagnoses in the first 139 patients (children and adults) in the Göteborg Epilepsy Surgery series. Temporal lobe resections were most common (54.0%) followed by frontal lobe (18.0%) and multilobar resections (11.5%). All histopathological specimens were re‐evaluated in connection with this study. Parenchymal malformations and atrophic‐gliotic lesions were the most common histopathological findings. Microdysgenesis was more common than major malformations (24.5% versus 11.5%). When the MRI scans were blindly re‐evaluated the MRI findings correlated with histopathological diagnosis in all of the vascular malformations, in 77.8% of the tumours, in 76.5% of the cases with hippocampal sclerosis but only in 28.6% of the major cortical development malformations. Hemispherectomies carried the best seizure outcome prognosis followed by temporal lobe resections (75.0% versus 57.3% seizure free 2 years after surgery). Vascular malformations carried the best, and microdysgenesis the worst prognosis (76.9% versus 39.4% seizure free).

Long term follow-up of the first 70 operated adults in the Göteborg Epilepsy Surgery Series with respect to seizures, psychosocial outcome and use of antiepileptic drugs

Objective: To compare long term (10 years) seizure outcome, psychosocial outcome and use of antiepileptic drugs (AED) with the 2 year follow-up in adults after resective epilepsy surgery. Methods: All adults (n = 70) who underwent resective epilepsy surgery from 1987 to 1995 in the Göteborg Epilepsy Surgery Series were included. Fifty-four had undergone temporal lobe resections and 16 extratemporal resections (12 frontal). A cross-sectional follow-up in the form of a semistructured interview was performed in late 2003. Results: Mean follow-up was 12.4 years (range 8.6–16.2). Of the 70 patients (51% males), five (7%) were dead (three as a result of non-epilepsy related causes). Of the 65 patients interviewed, 38 (58%) were seizure-free at the long term follow-up: 65% of the patients with temporal lobe resections and 36% of the patients with extratemporal resections. Of the 35 patients who were seizure-free at the 2 year follow-up, 3 (9%) had seizures at the long term follow-up. Of the 30 patients who had seizures at the 2 year follow-up, 6 (20%) were seizure-free at the long term follow-up. Of all 65 patients, 45 (69%) had the same seizure status as the 2 year follow-up. Sixteen (25%) had an improved seizure status and 4 (6%) had a worsened status. Of the seizure-free patients, 11 (29%) had ceased taking AED, 28 (74%) were working and 25 (66%) had a driving license. Conclusions: Adult patients who are seizure-free 2 years after resective epilepsy surgery are most likely to still be seizure-free 10 years later. Most are working and have obtained a driving license.

Long-term outcomes of epilepsy surgery in Sweden A national prospective and longitudinal study

Objective: To investigate prospective, population-based long-term outcomes concerning seizures and antiepileptic drug (AED) treatment after resective epilepsy surgery in Sweden. Methods: Ten- and 5-year follow-ups were performed in 2005 to 2007 for 278/327 patients after resective epilepsy surgery from 1995 to 1997 and 2000 to 2002, respectively. All patients had been prospectively followed in the Swedish National Epilepsy Surgery Register. Ninety-three patients, who were presurgically evaluated but not operated, served as controls. Results: In the long term (mean 7.6 years), 62% of operated adults and 50% of operated children were seizure-free, compared to 14% of nonoperated adults (p < 0.001) and 38% of nonoperated children (not significant). Forty-one percent of operated adults and 44% of operated children had sustained seizure freedom since surgery, compared to none of the controls (p < 0.0005). Multivariate analysis identified ≥30 seizures/month at baseline and long epilepsy duration as negative predictors and positive MRI to be a positive predictor of long-term seizure-free outcome. Ten years after surgery, 86% of seizure-free children and 43% of seizure-free adults had stopped AEDs in the surgery groups compared to none of the controls (p < 0.0005). Conclusions: This population-based, prospective study shows good long-term seizure outcomes after resective epilepsy surgery. The majority of the patients who are seizure-free after 5 and 10 years have sustained seizure freedom since surgery. Many patients who gain seizure freedom can successfully discontinue AEDs, more often children than adults. Classification of evidence: This study provides Class III evidence that more patients are seizure-free and have stopped AED treatment in the long term after resective epilepsy surgery than nonoperated epilepsy patients.

Tonic GABA(A) receptor-mediated currents in human brain.

GABAA receptors can mediate both phasic (synaptic) and tonic (extrasynaptic) forms of inhibition. It has been proposed that tonic inhibition plays a critical part in controlling neuronal and network excitability. Although tonic GABAA receptor‐mediated currents have been well characterized in rodents, their existence in human tissue has yet to be demonstrated. Here we show that tonic currents can be recorded from human tissue obtained from patients undergoing temporal lobectomies. Tonic GABAA receptor‐mediated currents were present in pyramidal cells and interneurons in layer V‐VI of temporal neocortex and granule cells in the dentate gyrus. These tonic currents have cell type‐specific pharmacologies, opening up the possibility of targeted therapeutics.

Bilateral diffusion tensor abnormalities of temporal lobe and cingulate gyrus white matter in children with temporal lobe epilepsy.

PURPOSE Bilateral diffusion tensor imaging (DTI) abnormalities have been reported in the white matter associated to the hippocampus in adults with mesial temporal lobe epilepsy (TLE). In children with a shorter duration of epilepsy, such changes may not have yet emerged. The aim of this study was to investigate interictal changes in the temporal lobe white matter (TLWM) and cingulate gyrus white matter (CGWM) of children with TLE using DTI. METHODS DTI was performed in eight children with TLE and 10 healthy, age-matched controls. Fractional anisotropy (FA), trace, parallel (lambda(||)) and perpendicular (lambda( perpendicular)) diffusivity were calculated for a volume of interest in the TLWM and CGWM on the seizure focus side and the contralateral side. Data were compared for differences between sides for patients and between patients and controls. RESULTS There was no significant difference in FA, trace, lambda(||) and lambda( perpendicular) between TLWM and CGWM on the seizure focus side versus the contralateral side in TLE patients. Increased diffusivity, lambda(||) and lambda( perpendicular) within the TLWM and CGWM were found in TLE patients compared to controls, but no significant difference in FA was seen. CONCLUSIONS Bilaterally increased diffusivity, lambda(||) and lambda( perpendicular) in the white matter in children with TLE may be related to seizure induced functional or structural changes. The preserved FA in our pediatric cohort is in contrast to the reduced FA in the white matter of adults with TLE and may relate to differences in the duration of epilepsy or in the vulnerability of white matter to seizures.

Visual field defects after temporal lobectomy – comparing methods and analysing resection size

Objectives – The frequency of visual field defects (VFD) after temporal lobe resections (TLR) was compared for two types of TLR and VFD frequency was correlated to resection size.