Werner J Z'Graggen

Werner J Z'Graggen
Inselspital, Universitätsspital Bern

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124
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Introduction

Publications

Publications (124)
Article
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Background: The objective was to investigate the role of gene expression and plasma levels of the muscular protein myostatin in intensive care unit-acquired weakness (ICUAW). This was performed to evaluate a potential clinical and/or pathophysiological rationale of therapeutic myostatin inhibition. Methods: A retrospective analysis from pooled d...
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Background Brain fog is a common and highly disturbing symptom for patients with neuropathic postural tachycardia syndrome (POTS). Cognitive deficits have been measured exclusively in the upright body position and mainly comprised impairments of higher cognitive functions. The cause of brain fog is still unclear today. This study aimed to investiga...
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Background and purpose: Knowledge about different etiologies of non-traumatic intracerebral hemorrhage (ICH) and their outcomes is scarce. Methods: We assessed prevalence of pre-specified ICH etiologies and their association with outcomes in consecutive ICH patients enrolled in the prospective Swiss Stroke Registry (2014 to 2019). Results: We...
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Background: The COVID-19 pandemic has greatly increased the incidence and clinical importance of critical illness myopathy (CIM), because it is one of the most common complications of modern intensive care medicine. Current diagnostic criteria only allow diagnosis of CIM at an advanced stage, so that patients are at risk of being overlooked, espec...
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Purpose of review Critical illness myopathy (CIM) is a common neuro-muscular complication of intensive care treatment associated with increased morbidity and mortality. The current guidelines for diagnosis include clinical and electrophysiological criteria as well as a muscle biopsy, and allow diagnosis only at an advanced stage of the disease. To...
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Objectives Cerebral vasospasm is a severe and potentially lethal complication in patients with subarachnoid hemorrhage (SAH). Its pathogenesis is still not completely understood. The efficacy of current treatments, such as triple-H therapy or calcium channel blockers, is unsatisfactory, and a new therapy model would therefore be valuable. Electrica...
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Background: Postural tachycardia syndrome (POTS) is a form of autonomic dysregulation. There is increasing evidence that the etiology may be immune-mediated in a subgroup of patients. Patients with POTS often experience an exacerbation of their symptoms associated with (viral) infections and often fear the same symptom aggravation after vaccination...
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Background We demonstrated experimentally that inhaled nitric oxide (iNO) dilates hypoperfused arterioles, increases tissue perfusion, and improves neurological outcome following subarachnoid hemorrhage (SAH) in mice. We performed a prospective pilot study to evaluate iNO in patients with delayed cerebral ischemia after SAH. Methods SAH patients w...
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Aims We assessed the association of prior antiplatelet therapy (APT) at onset of intracerebral haemorrhage (ICH) with haematoma characteristics and outcome. Methods We performed a systematic review and meta-analysis of studies comparing ICH outcomes of patients on APT (APT-ICH) with patients not taking APT (non–APT-ICH). Primary outcomes were haem...
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Purpose In neuropathic postural tachycardia syndrome, peripheral sympathetic dysfunction leads to excessive venous blood pooling during orthostasis. Up to 84% of patients report leg pain and weakness in the upright position. To explore possible pathophysiological processes underlying these symptoms, the present study examined muscle excitability de...
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Objective Uremic myopathy is a condition seen in end-stage renal disease (ESRD), characterized by muscle weakness and muscle fatigue, in which the pathophysiology is uncertain. The aim of this study was to assess the role of abnormal serum constituents in ESRD patients by relating them to the excitability properties of the tibialis anterior muscle,...
Article
OBJECTIVE Postoperative internal carotid artery (ICA) intimal flap (IF) is a potential complication after carotid endarterectomy (CEA) for carotid artery stenosis. There are no clear recommendations in the current literature on the management of this condition due to sparse evidence. Some authors advocate carotid stent placement or reoperation, whi...
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Background: Delayed cerebral ischemia and cerebral vasospasm remain the leading causes of poor outcome in survivors of aneurysmal subarachnoid hemorrhage. Refractory cerebral vasospasms can be treated with endovascular vasodilator therapy, which can either be performed in conscious sedation or general anesthesia. The aim of this study is to compare...
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The technique of multi-fiber muscle velocity recovery cycle recordings was developed as a diagnostic tool to assess muscle membrane potential changes and ion channel function in vivo. This study was undertaken to assess the impact of intermittent high frequency stimulation on muscle velocity recovery cycle components, and to study whether the chang...
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Background: Delayed cerebral ischemia and cerebral vasospasm remain the leading causes of poor outcome in survivors of aneurysmal subarachnoid hemorrhage. Refractory cerebral vasospasms can be treated with endovascular vasodilator therapy, which can either be performed in conscious sedation or general anesthesia. The aim of this study is to compare...
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Background The postural tachycardia syndrome (POTS) is a form of autonomic dysfunction characterized by symptoms of orthostatic intolerance, often accompanied by sudomotor dysfunction and gastrointestinal dysmotility. Recently, evidence has accumulated that in a subset of patients, the pathogenesis of dysautonomia may be immune‐mediated. The aim of...
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Background/Objective In order to monitor tissue oxygenation in patients with acute neurological disorders, probes for measurement of brain tissue oxygen tension (ptO 2 ) are often placed non-specifically in a right frontal lobe location. To improve the value of ptO 2 monitoring, placement of the probe into a specific area of interest is desirable....
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Background Early prognostication in patients with acute consciousness impairment is a challenging but essential task. Current prognostic guidelines vary with the underlying etiology. In particular, electroencephalography (EEG) is the most important paraclinical examination tool in patients with hypoxic ischemic encephalopathy (HIE), whereas it is n...
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Background: Muscular weakness and/or muscle wasting is recognized as a key medical problem in critically ill patients on intensive care units (ICUs) worldwide. Methods and results: Intensive care unit-acquired weakness (ICUAW) results from various diseases leading to critical illness and is observed in about 40% [1080/2686 patients, 95% confidence...
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OBJECTIVE With global aging, elective craniotomies are increasingly being performed in elderly patients. There is a paucity of prospective studies evaluating the impact of these procedures on the geriatric population. The goal of this study was to assess the safety of elective craniotomies for elderly patients in modern neurosurgery. METHODS For t...
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Although conventional nerve conduction studies (NCS) and electromyography (EMG) are suitable for the diagnosis of neuromuscular disorders, they provide limited information about muscle fiber membrane properties and underlying disease mechanisms. Muscle velocity recovery cycles (MVRCs) illustrate how the velocity of a muscle action potential depends...
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Metal artifacts resulting from coiling or clipping of a brain aneurysm degrade image quality and reduce diagnostic usefulness of computed tomography perfusion CTP. Our aim was to assess the diagnostic value of the iterative metal artifact reduction algorithm (iMAR) in CTP studies after coiling or clipping of ruptured intracranial aneurysms. Fifty-e...
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Background: Early diagnosis of delayed cerebral ischemia (DCI) in patients after aneurysmal subarachnoid hemorrhage (aSAH) still poses a leading problem in neurointensive care. The aim of this study was to analyze the effect of oral Nimodipine administration on systemic blood pressure in patients with evolving DCI compared to patients without DCI....
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Background Postural orthostatic tachycardia syndrome is a disorder of the autonomic nervous system. Approximately 30% of patients experience orthostatic headaches. Orthostatic headaches also are a hallmark symptom in spontaneous intracranial hypotension. While the cause of orthostatic headaches in spontaneous intracranial hypotension can be linked...
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Background: Postural tachycardia syndrome (POTS) is a form of autonomic dysregulation and is characterized by an excessive heart rate (HR) increment upon the upright body position while blood pressure is maintained. Patients experience typical symptoms of orthostatic intolerance such as dizziness, nausea and cognitive impairments. The present study...
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In a single-center, randomized trial involving 361 patients, the use of routine computed tomography after the removal of a chronic hematoma had no advantage over CT performed only in patients with clinical deterioration.
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Background: Electrical bicycles (E-bikes) allow people of all ages to ride at high speeds but have an inherent risk of traumatic brain injury (TBI). Their sales have increased tremendously in recent years. Methods: We performed a retrospective cohort study to compare the incidence and severity of TBI in E-bikers and conventional bicyclists. We i...
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Introduction Intensive care unit-acquired weakness (ICU-AW) is often observed in critically ill patients with prolonged intensive care unit (ICU) stay. We hypothesized that evolving metabolic abnormalities during prolonged ICU stay are reflected by changing nutrient patterns in blood, urine and skeletal muscle, and that these patterns differ in pat...
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Background and Purpose— Whether maximal treatment should be offered to elderly patients suffering from poor-grade aneurysmal subarachnoid hemorrhage (aSAH) is controversial. The survival of patients in this subgroup beyond the usual outcome measurements 6 to 12 months after aSAH is unclear. The purpose of this study is to provide survival and outco...
Article
Over the past decades, survival rates of critical illness have constantly increased. As a consequence, the incidences of important complications of intensive care unit (ICU) treatment become more and more prevalent. Critical illness myopathy (CIM) belongs to one of the most frequent neuromuscular complications and its presence is associated with pr...
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INTRODUCTION Chronic subdural hematoma has a high recurrence rate after surgery and postoperative scans often show substantial residuals, eventually leading to a higher rate of reoperation. However, the benefit of postsurgical imaging for patient outcome remains unknown. METHODS We randomly assigned 368 patients with newly diagnosed chronic subdur...
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Objective Spontaneous intracranial hypotension is caused by spinal cerebrospinal fluid leakage. Patients with orthostatic headaches and cerebrospinal fluid leakage show a decrease in optic nerve sheath diameter upon movement from supine to upright position. We hypothesized that the decrease in optic nerve sheath diameter upon gravitational challeng...
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Die Morbidität und Mortalität von Hirnschlagpatientinnen und -patienten konnten in den letzten Jahren dank Fortschritten der Akuttherapie, Schaffung von Stroke Centers und Optimierung der intensivmedizinschen Behandlung gesenkt werden.
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Au cours de ces dernières années, nous avons assisté à une diminution de la morbidité et de la mortalité des patients victimes d’un accident vasculaire cérébral grâce aux progrès accomplis dans le traitement aigu, à la création de «Stroke Units» et de «Stroke Centers», et à l’optimisation du traitement en soins intensifs.
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Spontaneous intracranial hypotension (SIH) has gained more attention in the eyes of clinicians in the past years and is now recognized as an important cause of headaches. While usually self-limiting and benign, some patients suffer from debilitating symptoms that interfere significantly with their social and professional life. Thus, recognition and...
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Background: External ventricular drainage (EVD) catheter placement is one of the most commonly performed neurosurgical procedures. The study's objective was to compare a computed tomography (CT) bolt scan-guided approach for the placement of EVDs with conventional landmark-based insertion. Methods: In this retrospective case-control study, we an...
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Introduction: Sepsis-induced myopathy and critical illness myopathy are common causes of muscle weakness in intensive care patients. This study investigated the effect of different mean arterial blood pressure (MAP) levels on muscle membrane properties following experimental sepsis. Methods: Sepsis was induced with faecal peritonitis in 12 out o...
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Introduction: The gain-of-function mutations that underlie sodium channel myotonia(SCM) and paramyotonia congenita(PMC) produce differing clinical phenotypes. We used muscle velocity recovery cycles (MVRCs) to investigate membrane properties. Methods: MVRCs and responses to trains of stimuli were compared in patients with SCM (n=9), PMC (N=8), a...
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In this study, we compared contrast-enhanced ultrasound perfusion imaging with magnetic resonance perfusion-weighted imaging or perfusion computed tomography for detecting normo-, hypo-, and nonperfused brain areas in acute middle cerebral artery stroke. We performed high mechanical index contrast-enhanced ultrasound perfusion imaging in 30 patient...
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Background and purpose: For patients with cerebral vasospasm refractory to medical and hemodynamic therapies, endovascular therapies often remain the last resort. Data from studies in large cohorts on the efficacy and safety of multiple immediate endovascular interventions are sparse. Our aim was to assess the feasibility and safety of multiple re...
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Objective: To visualize and treat spinal dural CSF leaks in all patients with intractable spontaneous intracranial hypotension (SIH) who underwent spinal microsurgical exploration. Methods: Patients presenting between February 2013 and July 2015 were included in this consecutive case series. The workup included spinal MRI without and with intrat...
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Introduction: Human muscle membrane properties can be assessed in vivo by recording muscle velocity recovery cycles (MVRCs). This study was undertaken to study the effect of muscle force training on MVRC parameters. Methods: MVRCs with 1 to 5 conditioning stimuli were recorded from brachioradialis muscle before and after 2 weeks of muscle force...
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Introduction: Patient management following elective cranial surgery often includes routine postoperative computed tomography (CT). We analyzed whether a regime of early extubation and close neurological monitoring without routine CT is safe, and compared the rate of postoperative emergency neurosurgical intervention with published data. Methods:...
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Muscular weakness and muscle wasting may often be observed in critically ill patients on intensive care units (ICUs) and may present as failure to wean from mechanical ventilation. Importantly, mounting data demonstrate that mechanical ventilation itself may induce progressive dysfunction of the main respiratory muscle, i.e. the diaphragm. The resp...
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Background: Perihematomal edema contributes to secondary brain injury in the course of intracerebral hemorrhage. The effect of decompressive surgery on perihematomal edema after intracerebral hemorrhage is unknown. This study analyzed the course of PHE in patients who were or were not treated with decompressive craniectomy. Methods: More than 10...
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Introduction: Myotonia in myotonic dystrophy types 1 (DM1) and 2 (DM2) is generally attributed to reduced chloride channel conductance. We used muscle velocity recovery cycles (MVRCs) to investigate muscle membrane properties in DM1 and DM2, with comparisons with myotonia congenita (MC). Methods: MVRCs and responses to repetitive stimulation wer...
Article
OBJECT Current data show a favorable outcome in up to 50% of patients with World Federation of Neurosurgical Societies (WFNS) Grade V subarachnoid hemorrhage (SAH) and a rather poor prediction of worst cases. Thus, the usefulness of the current WFNS grading system for identifying the worst scenarios for clinical studies and for making treatment dec...
Article
Full-text available
Spontaneous intracranial hypotension (SIH) is most commonly caused by cerebrospinal fluid (CSF) leakage. Therefore, we hypothesised that patients with orthostatic headache (OH) would show decreased optic nerve sheath diameter (ONSD) during changes from supine to upright position. Transorbital B-mode ultrasound was performed employing a high-frequen...
Article
Recording of muscle velocity recovery cycles (MVRCs) has been developed as a technique to investigate the pathophysiology of muscle diseases. MVRCs have been measured by direct muscle stimulation and concentric EMG needle recording. This study was undertaken to determine if recordings can be made with surface electrodes. MVRCs with 1 and 2 conditio...
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Introduction: Repeated diaphragm compound muscle action potential (CMAP) recordings may help to understand the pathophysiology of respiratory muscle weakness. Neurally adjusted ventilator assist (NAVA) uses esophageal EMG electrodes to drive the ventilator. We evaluated the feasibility of CMAP recordings using these electrodes and established norma...
Article
In susceptibility-weighted imaging (SWI) in the normal brain, cortical veins appear hypointense due to paramagnetic properties of deoxy-hemoglobin. Global cerebral anoxia decreases cerebral oxygen metabolism, thereby increasing oxy-hemoglobin levels in cerebral veins. We hypothesized that a lower cerebral oxygen extraction fraction in comatose pati...
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Object: After subarachnoid hemorrhage (SAH), seizure occurs in up to 26% of patients. The impact of seizure on outcome has been studied, yet its impact on grading is unknown. The authors evaluated the impact of early-onset seizures (EOS) on grading of spontaneous SAH and on outcome. Methods: This retrospective analysis included consecutive patie...
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Background and purposeHead-up tilt (HUT) testing is a widely used diagnostic tool in patients with suspected vasovagal syncope (VVS). However, no gold standard exists for this examination and the various protocols used have a limited sensitivity and specificity. Our aim was to determine the sensitivity of a sequential HUT testing protocol including...
Article
A 58-year old woman with a long-standing history of chronic recurrent headache, depression and anxiety presented with new onset occipital headaches, tinnitus, gait instability and worsening of mood disorder. A first extensive work-up failed to objectify a somatic disorder and a psychiatric origin was suspected. However, 6 weeks later focal neurolog...
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Object: The etiology of chronic subdural hematoma (CSDH) in nongeriatric patients (≤ 60 years old) often remains unclear. The primary objective of this study was to identify spinal CSF leaks in young patients, after formulating the hypothesis that spinal CSF leaks are causally related to CSDH. Methods: All consecutive patients 60 years of age or...
Article
Aims: Patient management following elective cranial surgery varies between different neurosurgical institutions. Early routine postoperative cranial computed tomography (CT) is often performed while keeping patients sedated and ventilated for several hours. We hypothesize that fast track management without routine CT scanning, i.e., early extubatio...
Article
Aim: Current data show a favorable outcome in up to 50% of patients with World Federation of Neurosurgical Societies (WFNS) grade V subarachnoid hemorrhage (SAH) and a rather poor prediction of worst cases. Thus, the usefulness of the current WFNS grading for clinical studies and for making treatment decisions is limited. One reason for this lack o...
Article
Aim: The etiology of chronic subdural hematoma (cSDH) in non-geriatric patients (≤60 years) often remains unclear. The primary objective of this study was to identify spinal cerebrospinal fluid (CSF) leaks in young patients with the hypothesis that spinal CSF leaks are causally related to cSDH. Methods: All consecutive patients 60 years of age or...
Article
Full-text available
Hyperkalemia is an important cause of membrane depolarization in renal failure. A recent theoretical model of axonal excitability explains the effects of potassium on threshold electrotonus, but predicts changes in superexcitability in the opposite direction to those observed. To resolve this contradiction we assessed the relationship between serum...