Operative Nuances of Stereotactic Leksell Frame-Based Depth Electrode Implantation.

Background: For intracranial electroencephalographic monitoring, stereotactically implanted depth electrodes are increasingly used at epilepsy centers around the world. Objective: To identify pearls and pitfalls from our experience with stereotactic Leksell (Elekta AB, Stockhom, Sweden) frame-based depth electrode implantation. Methods: An intraoperative video of the implantation technique was recorded. Results: A detailed description and a video on how to implant depth electrodes using the stereotactic Leksell frame is provided. Conclusion: Neurosurgeons implanting depth electrodes for intracranial electroencephalographic monitoring might find the technical nuances and caveats described in this technical note useful for their practice.

Case Report: Free Latissimus Dorsi Flap in Combination With Subdural Space Reduction for the Prevention of Recurrent Hemorrhage Following Hemispherectomy.

BACKGROUND AND IMPORTANCE: Extensive cerebral resections for the treatment of epilepsy may result in a large intracranial dead space that is prone to recurrent hemorrhage, either due to mechanical dislodgement or the development of extensive subdural membranes. Several techniques have been proposed to decrease the risk of hemorrhage by either reducing or filling the remaining intracranial dead space. CLINICAL PRESENTATION: We present a case of persistent hemorrhage following functional hemispherectomy in a patient with a large porencephalic cyst. A treatment strategy involving both subdural space reduction and cranial vault filling with a vascularized free latissimus dorsi flap is discussed. CONCLUSION: Subdural space reduction and cranial vault filling with a vascularized free latissimus dorsi flap is a viable treatment alternative in patients with large areas of intracranial dead space.

Electroencephalographic Recordings During Withdrawal of Life-Sustaining Therapy Until 30 Minutes After Declaration of Death.

BACKGROUND: The timing of the circulatory determination of death for organ donation presents a medical and ethical challenge. Concerns have been raised about the timing of electrocerebral inactivity in relation to the cessation of circulatory function in organ donation after cardio-circulatory death. Nonprocessed electroencephalographic (EEG) measures have not been characterized and may provide insight into neurological function during this process. METHODS: We assessed electrocortical data in relation to cardiac function after withdrawal of life-sustaining therapy and in the postmortem period after cardiac arrest for four patients in a Canadian intensive care unit. Subhairline EEG and cardio-circulatory monitoring including electrocardiogram, arterial blood pressure (ABP), and oxygen saturation were captured. RESULTS: Electrocerebral inactivity preceded the cessation of the cardiac rhythm and ABP in three patients. In one patient, single delta wave bursts persisted following the cessation of both the cardiac rhythm and ABP. There was a significant difference in EEG amplitude between the 30-minute period before and the 5-minute period following ABP cessation for the group, but we did not observe any well-defined EEG states following the early cardiac arrest period. CONCLUSIONS: In a case series of four patients, EEG inactivity preceded electrocardiogram and ABP inactivity during the dying process in three patients. Further study of the electroencephalogram during the withdrawal of life sustaining therapies will add clarity to medical, ethical, and legal concerns for donation after circulatory determined death.

Traumatic encephalopathy.

Traumatic brain injury is the leading cause of death and disability among young adults. Clinical evaluation is of limited value in the assessment of patients with traumatic brain injury and is often inaccurate in determining the extent of brain damage. Neurophysiological techniques and neuroimaging can provide valuable prognostic information and are useful in monitoring for seizures and other causes of secondary brain damage and in tracking the effects of therapy. More recently, cognitive electrophysiology and functional magnetic resonance imaging have shown that many patients clinically deemed to be in vegetative or in minimally conscious states are, in fact, aware. This opens new frontiers for further research into establishing communication with otherwise unresponsive patients.

New guidelines for the initial management of head injury.

The majority of patients presenting with mild head trauma will have no intracranial pathology and can be safely discharged home. It is estimated that 10% to 15% of these patients will have clinically significant findings on computed tomography imaging and up to 1% may require neurosurgical intervention. The revised Scandinavian Head Trauma Guidelines provide an evidence- and consensus-based algorithm to assist physicians in determining which patients presenting with minimal, mild or moderate blunt head injury are at higher risk for intracranial pathology and thus require neuroimaging and hospital admission. Striking a balance between health care costs and risk of morbidity remains an ongoing challenge and we will present our concerns with this useful, but conservative management algorithm.

Brain type carnosinase in dementia: a pilot study.

BACKGROUND: The pathological processes underlying dementia are poorly understood and so are the markers which identify them. Carnosinase is a dipeptidase found almost exclusively in brain and serum. Carnosinase and its substrate carnosine have been linked to neuropathophysiological processes. METHODS: Carnosinase activity was measured by a flourometric method in 37 patients attending a Geriatric Outpatient Clinic. There were 17 patients without dementia, 13 had Alzheimer's disease (AD) and 7 had mixed dementia (MD). RESULTS: The range of serum carnosinase activity for patients without dementia was 14.5 - 78.5 micromol/ml/h. There was no difference in carnosinase activity between patients without dementia (40.3 +/- 15.2 micromol/ml/h) and patients with AD (44.4 +/- 12.4 micromol/ml/h) or MD (26.6 +/- 15 micromol/ml/h). However, levels in the MD group were significantly lower than the AD group (p = 0.01). This difference remained significant after adjusting for gender, MMSE score, exercise, but not age, one at a time and all combined. The effect of other medical conditions did not remove the significance between the AD and MD groups. The MD group, but not the AD group, demonstrated a significant trend with carnosinase activity decreasing with duration of disease (from first recorded date of diagnosis to date of blood collection) (r = -0.76, p = 0.049). There was no association with carnosinase activity and MMSE score in the AD or MD group. Both AD and MD patients on any dementia medication (donepezil, galantamine, memantine) had higher carnosinase activity compared to those not taking a dementia medication. Carnosinase activity was higher in patients who regularly exercised (n = 20) compared to those who did not exercise regularly (n = 17)(p = 0.006). CONCLUSION: This exploratory study has shown altered activities of the enzyme carnosinase in patients with dementia.