Wolfram Scharbrodt

Clinical and methodological precision of spinal navigation assisted by 3D intraoperative O-arm radiographic imaging

OBJECT In recent years, the importance of intraoperative navigation in neurosurgery has been increasing. Multiple studies have proven the advantages and safety of computer-assisted spinal neurosurgery. The use of intraoperative 3D radiographic imaging to acquire image information for navigational purposes has several advantages and should increase the accuracy and safety of screw guidance with navigation. The aim of this study was to evaluate the clinical and methodological precision of navigated spine surgery in combination with the O-arm multidimensional imaging system. METHODS Thoracic, lumbar, and sacral pedicle screws that were placed with the help of the combination of the O-arm and StealthStation TREON plus navigation systems were analyzed. To evaluate clinical precision, 278 polyaxial pedicle screws in 139 vertebrae were reviewed for medial or caudal perforations on coronal projection. For the evaluation of the methodological accuracy, virtual and intraoperative images were compared, and the angulation of the pedicle screw to the midsagittal line was measured. RESULTS Pedicle perforations were recorded in 3.2% of pedicle screws. None of the perforated pedicle screws damaged a nerve root. The difference in angulation between the actual and virtual pedicle screws was 2.8° ± 1.9°. CONCLUSIONS The use of the StealthStation TREON plus navigation system in combination with the O-arm system showed the highest accuracy for spinal navigation compared with other studies that used traditional image acquisition and registration for navigation.

The prediction of long-term outcome after subarachnoid hemorrhage as measured by the Short Form-36 Health Survey

The Glasgow Outcome Scale (GOS) score is widely used to assess outcome after a subarachnoid hemorrhage (SAH). Patients who have recovered fully or with a mild disability (GOS scores 4 and 5) frequently complain about difficulties in conducting their daily activities. The Short Form-36 (SF-36) Health Survey is a questionnaire that assesses outcomes in multiple categories. This study was conducted to compare the quality of outcome assessment between the SF-36 Health Survey and GOS scores. A total of 128 patients with SAH (all data expressed as mean+/-standard deviation) aged 53.1+/-12.1 years, and a mean Hunt and Hess grade on admission of 2+/-1, were retrospectively included in the study. Medical charts were reviewed to assess previous medical history, location of the aneurysm and the presence of vasospasm. The SF-36 and GOS scores were collected in structured interviews approximately 5 years (+/-2 years) after the SAH. The SF-36 data were compared to a historical healthy control cohort of 2,474 individuals. The results showed that 52% of patients experienced a favourable outcome after SAH (GOS scores 4 and 5). Vasospasm was recorded in 25% of patients. However, the average SF-36 results were lower in all tested categories for patients after SAH than the healthy normal controls. None of the SF-36 categories except physical function correlated significantly with the GOS score. Aneurysm location did not have an impact on SF-36 data. Patients after a SAH assessed as GOS score 5 are significantly impaired in social functioning and general health. We conclude that patients continue to suffer neuropsychological deficits years after a SAH. The GOS score is a rough outcome measure that primarily focuses on physical functioning. SF-36 is a useful tool to include in the neuropsychological outcome assessment of patients with SAH.

Cytosolic Ca2+ Oscillations in Human Cerebrovascular Endothelial Cells after Subarachnoid Hemorrhage

Molecular mechanisms of cerebral vasospasm after subarachnoid hemorrhage (SAH) include specific modes of cell signaling like activation of nuclear factor (NF)-kB and vascular cell adhesion molecules (VCAM)-1 expression. The studys hypothesis is that cisternal cerebral spinal fluid (CSF) from patients after SAH may cause Ca2+ oscillations which induce these modes of vascular inflammation in an in vitro model of human cerebral endothelial cells (HCECs). HCECs were incubated with cisternal CSF from 10 SAH patients with confirmed cerebral vasospasm. The CSF was collected on days 5 and 6 after hemorrhage. Cytosolic Ca2+ concentrations and cell contraction as an indicator of endothelial barrier function were examined by fura-2 microflurometry. Activation of NF-κB and VCAM-1 expression were measured by immunocytochemistry. Incubation of HCEC with SAH-CSF provoked cytosolic Ca2+ oscillations (0.31 ± 0.09 per min), cell contraction, NF-κB activation, and VCAM-1 expression, whereas exposure to native CSF had no significant effect. When endoplasmic reticulum (ER) Ca2+-ATPase and ER inositol trisphosphate (IP3)-sensitive Ca2+ channels were blocked by thapsigargin or xestospongin, the frequency of the Ca2+ oscillations was reduced significantly. In analogy to the reduction of Ca2+ oscillation frequency, the blockers impaired HCEC contraction, NF-κB activation, and VCAM-1 expression. Cisternal SAH-CSF induces cytosolic Ca2+ oscillations in HCEC that results in cellular constriction, NF-κB activation, and VCAM-1 expression. The Ca2+ oscillations depend on the function of ER Ca2+-ATPase and IP3-sensitive Ca2+ channels.

Cerebral energy failure after subarachnoid hemorrhage: the role of relative hyperglycolysis.

After subarachnoid hemorrhage (SAH) cerebral metabolism is significantly impaired. Hyperglycolysis describes the reduction of oxidative metabolism followed by a relative increase of anaerobic glycolysis to maintain energy supply. This phenomenon is known in head injury but has not as yet been shown after SAH. This study was conducted to test the hypothesis that hyperglycolysis is present in SAH patients and is associated with vasospasm. A total of 105 measurements were conducted on 21 SAH patients (age 49+/-15 years, median World Federation of Neurosurgical Societies Grade 4) over the first 5 days following admission. Arteriovenous differences were calculated for oxygen (avDO2) and glucose (avDGlc). Relative hyperglycolysis was defined as metabolic ratio (MR=avDO2[mmol/L]/avDGlc[mmol/L])<3.44. Jugular-venous saturation for oxygen (SjvO2), mean arterial blood pressure (MAP), intracranial pressure (ICP), cerebral perfusion pressure (CPP) were monitored. Relative hyperglycolyis was recorded in 34% of studies after SAH. In hyperglycolytic studies both jugular-venous lactate and SjvO2 were significantly elevated (jugular-venous lactate 14.9+/-9.9 vs. 11.8+/-5.5 mg/dL, p=0.04; SjvO2: 70.0+/-18% vs. 81.7+/-9%, p=0.002). Relative hyperglycolysis is associated with outcome after SAH. In patients who died after SAH almost 50% of studies showed hyperglycolysis, whereas patients who survived without neurological deficit had no hyperglycolytic events. Relative hyperglycolysis is a common event after SAH. It may be associated with relative hyperemia but most importantly with outcome.

Endoscopic surgical anatomy of the paediatric third ventricle studied using virtual neuroendoscopy based on 3-D ultrasonography

IntroductionEndoscopic treatment for occlusive hydrocephalus requires knowledge of individual ventricular and vascular anatomies of the ventricular system.MethodsWe studied the feasibility of virtual neuroendoscopy (VNE) based on 3-D ultrasonography (3-D US) for the identification of parenchymal and vascular anatomical landmarks of the third ventricle and its impact on the surgical planning of endoscopic third ventriculostomy (ETV) in paediatric patients. 3-D US was performed through the anterior fontanel in four infants with hydrocephalus.ResultsVirtual neuroendoscopy revealed the size of the foramen of Monro, anatomical landmarks of the floor of the third ventricle crucial for correct fenestration during ETV, but not the premesencephalic cistern. The basilar bifurcation was identified in relation to the floor of the third ventricle by VNE (power-Doppler ultrasonography) and confirmed intraoperatively after ETV.Conclusion3-D US-based VNE reveals detailed anatomical information on the ventricular system including the foramen of Monro and the floor of the third ventricle. Within the premesencephalic cistern vascular anatomy can be visualized, but not non-vascular structures.

Mean hemoglobin concentration after acute subarachnoid hemorrhage and the relation to outcome, mortality, vasospasm, and brain infarction.

Lower mean hemoglobin (HGB) levels are associated with unfavorable outcome after spontaneous subarachnoid hemorrhage (SAH). Currently, there is no cutoff level for mean HGB levels associated with unfavorable outcome. This study was conducted to evaluate a threshold for mean HGB concentrations after SAH, and to observe the relation to outcome. The medical records of 702 patients with spontaneous SAH were reviewed. Predictors of outcome were proved by univariate analysis. Predictors with p<0.1 were included in a multivariate binary logistic regression model. Cutoff points for mean HGB levels were calculated by receiver operating characteristic curve analysis. Mean HGB was 11.9 g/dl (±standard deviation [SD] 1.7 g/dl) in patients with favorable outcome compared to 10.8 g/dl (±SD 1.1g/dl) in patients with unfavorable outcome (p<0.001). The highest Youdens index value was found for a HGB cutoff at 11.1 g/dl. In a binary logistic regression model, predictors of unfavorable outcome were identified as an initially high Hunt-Hess grade (odds ratio [OR]: 7.7; 95% confidence interval [CI]: 4.4-13.4; p<0.001), cerebral infarction on a CT scan during hospital stay (OR: 3.8; 95% CI: 2.0-7.3; p<0.001), rebleeding during the hospital stay (OR: 3.5; 95% CI: 1.6-8.0; p=0.002), mean HGB concentration <11.1g/dl (OR: 3.3; 95% CI: 2.0-5.3; p<0.001), and hydrocephalus (OR: 2.3; 95% CI: 1.4-3.7; p=0.001). In conclusion, a mean HGB concentration <11.1 g/dl during the hospital stay was associated with unfavorable outcome after acute SAH.

Basic Fibroblast Growth Factor–Induced Endothelial Proliferation and NO Synthesis Involves Inward Rectifier K+ Current

Objectives—Inward rectifier K+ currents (Kir) determine the resting membrane potential and thereby modulate essential Ca2+-dependent pathways, like cell growth and synthesis of vasoactive agents in endothelial cells. Basic fibroblast growth factor (bFGF) acts as a vasodilatator and angiogenic factor. Therefore, we investigated the effect of bFGF on Kir and assessed the role in proliferation and nitric oxide (NO) formation of endothelial cells. Methods and Results—Using the patch-clamp technique, we found characteristic Kir in human umbilical cord vein endothelial cells (HUVEC), which were dose-dependently blocked by barium (10 to 100 μmol/L). Perfusion with bFGF (50 ng/mL) caused a significant increase of Kir, which was blocked by 100 μmol/L barium (n=18, P <0.01). The bFGF-induced HUVEC proliferation was significantly inhibited when using 50 to 100 μmol/L barium (n=6; P <0.01). NO production was examined using a cGMP radioimmunoassay. bFGF caused a significant increase of cGMP levels (n =10; P <0.05), which were blocked by barium. Conclusions—Modulation of Kir plays an important role in bFGF-mediated endothelial cell growth and NO formation.

Parenteral and enteral nutrition in the management of neurosurgical patients in the intensive care unit

The iatrogenic malnutrition of neurosurgical patients in intensive care units (ICU) is an underestimated problem. It may cause a decrease in plasma albumin and oncotic pressure, leading to an increase in the amount of water entering the brain and increased intracranial pressure (ICP). This study was conducted to test the hypothesis that combined high-protein parenteral and enteral nutrition is beneficial for neurosurgical patients in ICU. A total of 202 neurosurgical patients in ICU (mean age+/-standard deviation, 56 years+/-16 years; male:female=1.2:1) were studied. Two consecutive 1-year time periods were compared, during which two different nutritional regimens were followed. In the first time period (Y1) patients were given a low-protein/high-fat formulation parenterally, followed by a standard enteral regimen. In the second time period (Y2) a protein-rich, combined parenteral and enteral diet was prospectively administered. The Glasgow Outcome Score was measured at 3-6 months after discharge. The following clinical parameters were recorded during the first 2 weeks after admission: ICP; albumin; cholinesterase (CHE); daily hours of ICP > 20 mmHg and cerebral perfusion pressure<70 mmHg; and Acute Physiology and Chronic Health Evaluation II (APACHE II) score. It was found that overall albumin (32.4 g/L+/-4.1g/L vs. 27.5 g/L+/-3.6g/L) and CHE was higher during Y2, although the total energy supply, glucose and fat intake was lower. Higher GOS scores were seen when patients had lower APACHE II scores and received the Y2 nutritional regimen. During Y2, the total hours of ICP > 20 mmHg were fewer. With the Y2 nutrition, maintenance of adequate cerebral perfusion required less catecholamine medication and colloidal fluid replacement. Therefore, adequate nutrition is an important parameter in the management of neurosurgical patients in ICU.

The Mechanisms of Energy Crisis in Human Astrocytes After Subarachnoid Hemorrhage

BACKGROUND Calcium (Ca2+) is a cofactor of multiple cellular processes. The mechanisms that lead to elevated cytosolic Ca2+ concentration are unclear. OBJECTIVE To illuminate how bloody cerebrospinal fluid (bCSF) from patients with intraventricular hemorrhage causes cell death of cultured human astrocytes. METHODS Cultured astrocytes were incubated with bCSF. In control experiments, native CSF was used. Cytosolic Ca2+ concentration was measured by fura-2 fluorescence. Apoptosis and necrosis were evaluated by staining with Hoechst-3342 and propidium iodide. RESULTS Incubation of astrocytes with bCSF provoked a steep Ca2+ concentration peak that was followed by a slow Ca2+ rise during the observation period of 50 minutes. Necrosis, but not apoptosis, was induced. Blockade of ATP-sensitive P2 receptors with suramin inhibited the bCSF-induced initial Ca2+ peak and necrosis. Blockade of P1 receptors with 8-phenyltheophylline or of N-methyl-D-aspartate receptors with D(-)-2-amino-5-phosphopentanoic acid had no significant effect. Preincubation with xestospongin D, a blocker of inositol 1,4,5-trisphosphate receptors, prevented the initial Ca2+ rise and reduced the rate of necrosis. Preemptying of the endoplasmic reticulum with thapsigargin protected astrocytes from the bCSF-induced Ca2+ peak. Inhibition of mitochondrial permeability transition pores opening with cyclosporin A reduced the rate of astrocytic necrosis significantly, although it did not influence the initial Ca peak. CONCLUSION bCSF elicits a steep, transient Ca rise when administered to human astrocytes by activation of ATP-sensitive P2 receptors and subsequent inositol 1,4,5-trisphosphate-dependent Ca release from endoplasmic reticulum. This massive Ca overload leads to subsequent mitochondrial permeability transition pores opening and necrosis of the cells.

The Prediction of 30-Day Mortality and Functional Outcome in Spontaneous Intracerebral Hemorrhage with Secondary Ventricular Hemorrhage: A Score Comparison

The original ICH (oICH) score was tested in different populations and showed good accuracy in the prediction of outcome and 30-day mortality after spontaneous ICH. The oICH was developed to stratify patients with all types of spontaneous intracerebral hemorrhage (SICH). Several modifications of the oICH score exist in the literature.In the current study, we tested the oICH score, two modified ICH scores, and the IVH score on a cohort of 171 patients with SICH and mandatory secondary intraventricular hemorrhage (IVH). Receiver-operating characteristic (ROC) curves were plotted, and the areas under the curves (AUC) were calculated for each score.The calculated AUCs for the prediction of 30-day mortality in the cohort were 0.736, 0.816, 0.805, and 0.836 for the original ICH, the mICH-A, the mICH-B, and the new IVH score, respectively. The best AUC for functional outcome was observed for the mICH-B score (0.823). For the mICH-A and the IVH score, an AUC of 0.811 was calculated.The scores that include the quantification of IVH or the grading of hydrocephalus show good accuracy in the prediction of 30-day mortality and functional outcome at 6 months in SICH with secondary IVH.