Claudius Thomé

University of Innsbruck, Innsbruck, Tyrol, Austria

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Publications (108)279.91 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: There is a substantial amount of evidence from animal models that early brain injury (EBI) may play an important role for secondary brain injury after aneurysmal subarachnoid hemorrhage (aSAH). Cerebral microdialysis (CMD) allows online measurement of brain metabolites including the pro-inflammatory-cytokine interleukin-6 (IL-6) and matrix-metalloproteinase-9 (MMP-9) which is indicative for disruption of the blood-brain-barrier. Twenty-six consecutive poor-grade aSAH patients with multimodal neuromonitoring were analyzed for brain hemodynamic and metabolic changes including CMD-IL-6 and CMD-MMP-9 levels. Statistical analysis was performed using a generalized estimating equation with an autoregressive function. The baseline metabolic central nervous system (CNS) profile revealed brain metabolic distress and an excitatory response which improved over the following 5 days (P <0.001). Brain tissue hypoxia (PbtO2 < 20 mmHg) was common (>60% of patients) in the first 24 hours of neuromonitoring and improved thereafter (P <0.05). Baseline CMD-IL-6 and CMD-MMP-9-levels were elevated in all patients (median = 4059 pg/ml, interquartile range (IQR) = 1316 to 12456 pg/ml and median = 851 pg/ml, IQR = 98 to 25860 pg/ml) and significantly decreased over the days (P <0.05). A higher pro-inflammatory response was associated with the development of delayed cerebral ischemia (P = 0.04), whereas admission disease severity and early brain tissue hypoxia were associated with higher CMD-MMP-9 levels (P <0.03). Brain metabolic distress and increased IL-6 levels were associated with poor functional outcome (mRS >3, P ≤0.01). All models were adjusted for probe location, aneurysm securing procedure and disease severity as appropriate. Multimodal neuromonitoring techniques allow insight into pathophysiologic changes in the early phase after aSAH. The results may be used as endpoints for future interventions targeting early brain injury in poor-grade aSAH patients.
    Critical Care 12/2015; 19(1). DOI:10.1186/s13054-015-0809-9 · 5.04 Impact Factor
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    ABSTRACT: Background Cerebral edema and delayed cerebral infarction (DCI) are common complications after aneurysmal subarachnoid hemorrhage (aSAH) and associated with poor functional outcome. Experimental data suggest that the amino acid taurine is released into the brain extracellular space secondary to cytotoxic edema and brain tissue hypoxia, and therefore may serve as a biomarker for secondary brain injury after aSAH. On the other hand, neuroprotective mechanisms of taurine treatment have been described in the experimental setting. Methods We analyzed cerebral taurine levels using high-performance liquid chromatography in the brain extracellular fluid of 25 consecutive aSAH patients with multimodal neuromonitoring including cerebral microdialysis (CMD). Patient characteristics and clinical course were prospectively recorded. Associations with CMD-taurine levels were analyzed using generalized estimating equations with an autoregressive process to handle repeated observations within subjects. Results CMD-taurine levels were highest in the first days after aSAH (11.2 ± 3.2 µM/l) and significantly decreased over time (p N = 20; 80 %) and patients developing DCI (N = 5; 20 %) had higher brain extracellular taurine levels compared to those without (Wald = 7.3, df = 1, p p = 0.001, respectively) even after adjusting for disease severity and CMD-probe location. There was no correlation between parenteral taurine supplementation and brain extracellular taurine (p = 0.6). Moreover, a significant correlation with brain extracellular glutamate (r = 0.82, p r = 0.56, p r = 0.39, p r = 0.37, p = 0.01), and lactate-to-pyruvate ratio (r = 0.24, p = 0.02) was found. Conclusions Significantly higher CMD-taurine levels were found in patients with brain edema or DCI after aneurysmal subarachnoid hemorrhage. Its value as a potential biomarker deserves further investigation.
    Neurocritical Care 04/2015; DOI:10.1007/s12028-015-0140-y · 2.60 Impact Factor
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    ABSTRACT: Cell-based regenerative approaches have been suggested as primary or adjuvant procedures for the treatment of degenerated intervertebral disc (IVD) diseases. Our aim was to evaluate the regenerative and immunogenic properties of mildly and severely degenerated cervical nucleus pulposus (NP) cells with regard to cell isolation, proliferation and differentiation, as well as to cell surface markers and co-cultures with autologous or allogeneic peripheral blood mononuclear cells (PBMC) including changes in their immunogenic properties after 3-dimensional (3D)-culture. Tissue from the NP compartment of 10 patients with mild or severe grades of IVD degeneration was collected. Cells were isolated, expanded with and without basic fibroblast growth factor and cultured in 3D fibrin/poly (lactic-co-glycolic) acid transplants for 21 days. Real-time reverse-transcription polymerase chain reaction (RT-PCR) showed the expression of characteristic NP markers ACAN, COL1A1 and COL2A1 in 2D- and 3D-culture with degeneration- and culture-dependent differences. In a 5,6-carboxyfluorescein diacetate N-succinimidyl ester-based proliferation assay, NP cells in monolayer, regardless of their grade of degeneration, did not provoke a significant proliferation response in T cells, natural killer (NK) cells or B cells, not only with donor PBMC, but also with allogeneic PBMC. In conjunction with low inflammatory cytokine expression, analyzed by Cytometric Bead Array and fluorescence-activated cell sorting (FACS), a low immunogenicity can be assumed, facilitating possible therapeutic approaches. In 3D-culture, however, we found elevated immune cell proliferation levels, and there was a general trend to higher responses for NP cells from severely degenerated IVD tissue. This emphasizes the importance of considering the specific immunological alterations when including biomaterials in a therapeutic concept. The overall expression of Fas receptor, found on cultured NP cells, could have disadvantageous implications on their potential therapeutic applications because they could be the targets of cytotoxic T-cell activity acting by Fas ligand-induced apoptosis.
    PLoS ONE 01/2015; 10(5):e0126954. DOI:10.1371/journal.pone.0126954 · 3.53 Impact Factor
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    ABSTRACT: Intervertebral disc (IVD) degeneration has been described as an aberrant, cell-mediated, age- and genetics-dependent molecular degeneration process, which can be accelerated by nutritional, mechanical and toxic factors. Collective involvement of these factors can result in structural failures, which are often associated with pain. Current treatment approaches are restricted to symptomatic therapies, not addressing options of restoring structural or biological deterioration of the IVD as the underlying problem. Therapeutic potentials of IVD cell transplantation, biomaterials, inhibiting or activating bioactive factors, including gene-therapeutic approaches, have been shown in vitro or in small animal models. Since human degenerative IVD cells display distinctive features with regard to cell biology and regenerative potential, we attempted a systematic review, investigating the in vitro response of human nucleus pulposus cells to different stimuli. Therefore, we conducted an electronic database search on Medline through July 2011 to identify, compare and discuss publications concerning the effects of cell-cell stimulation, bioactive factors, biomaterials and combinations thereof in terms of cell isolation, proliferation, differentiation and matrix protein synthesis. This survey and discussion might serve as a source for designing future biological treatment strategies for the human IVD. Copyright © 2012 John Wiley & Sons, Ltd.
    Journal of Tissue Engineering and Regenerative Medicine 12/2014; 8(12). DOI:10.1002/term.1583 · 4.43 Impact Factor
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    ABSTRACT: Cervical radiculopathy caused by spondylotic foraminal stenosis may require surgical treatment. Surgical options include anterior cervical foraminotomy and fusion or posterior cervical foraminotomy. Controversy remains regarding the preferable surgical approach. Pertinent clinical evidence is limited to low-quality observational reports. Therefore, treatment decisions are predominantly based on the individual surgeon's preference and skill. The study objective is to evaluate the efficacy and safety of posterior foraminotomy in comparison to anterior foraminotomy with fusion for the treatment of spondylotic foraminal stenosis. Methods/design: This is a multicenter randomized, controlled, parallel group superiority trial. A total of 88 adult patients are allocated in a ratio of 1:1. Sample size and power calculations were performed to detect the minimal clinically important difference of 14 points, with an expected standard deviation of 20 in the primary outcome parameter, Neck Disability Index, with a power of 80%, based on an assumed maximal dropout rate of 20%. Secondary outcome parameters include the Core Outcome Measures Index, which investigates pain, back-specific function, work disability, social disability and patient satisfaction. Changes in physical and mental health are evaluated using the Short Form-12 (SF-12) questionnaire. Moreover, radiological and health economic outcomes are evaluated. Follow-up is performed 3, 6, 12, 24, 36, 48 and 60 months after surgery. Major inclusion criteria are cervical spondylotic foraminal stenosis causing radiculopathy of C5, C6 or C7 and requiring decompression of one or two neuroforaminae. Study data generation (study sites) and data storage, processing and statistical analysis (Department of Medical Statistics, Informatics and Health Economics) are clearly separated. Data will be analyzed according to the intention-to-treat principle.
    Trials 11/2014; 15(1):437. DOI:10.1186/1745-6215-15-437 · 2.12 Impact Factor
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    ABSTRACT: Traumatic brain injury (TBI) is an important cause of death and disability. Safety and pharmacodynamics of 4-amino-tetrahydrobiopterin (VAS203), a nitric oxide (NO)-synthase inhibitor, were assessed in TBI in an exploratory Phase IIa study (NOSynthase Inhibition in TRAumatic brain injury=NOSTRA). The study included 32 patients with TBI in six European centers. In a first open Cohort, eight patients received three 12-h intravenous infusions of VAS203 followed by a 12-h infusion-free interval over 3 days (total dose 15 mg/kg). Patients in Cohorts 2 and 3 (24) were randomized 2:1 to receive either VAS203 or placebo as an infusion for 48 or 72 h, respectively (total dose 20 and 30 mg/kg). Effects of VAS203 on intracranial pressure (ICP), cerebral perfusion pressure (CPP), brain metabolism using microdialysis, and the therapy intensity level (TIL) were end points. In addition, exploratory analysis of the extended Glasgow Outcome Score (eGOS) after 6 months was performed. Metabolites of VAS203 were detected in cerebral microdialysates. No significant differences between treatment and placebo groups were observed for ICP, CPP, and brain metabolism. TIL on day 6 was significantly decreased (p<0.04) in the VAS203 treated patients. The eGOS after 6 months was significantly higher in treated patients compared with placebo (p<0.01). VAS203 was not associated with hepatic, hematologic, or cardiac toxic effects. At the highest dose administered, four of eight patients receiving VAS203 showed transitory acute kidney injury (stage 2-3). In conclusion, the significant improvement in clinical outcome indicates VAS203-mediated neuroprotection after TBI. At the highest dose, VAS203 is associated with a risk of acute kidney injury. KEYWORDS: NO-synthase inhibition; clinical trial; microdialysis; traumatic brain injury
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    ABSTRACT: Background Spontaneous intracerebral hemorrhage (ICH) is associated with high morbidity and mortality. Cortical spreading depolarizations (CSDs) increase brain matrix metalloproteinase (MMP)-9 activity leading to perihematomal edema expansion in experimental ICH. Methods The purpose of this report is to describe cerebral metabolic changes and brain extracellular MMP-9 levels in a patient with CSDs and perihematomal edema expansion after ICH. Results We present a 66-year-old male patient with ICH who underwent craniotomy for hematoma evacuation. Multimodal neuromonitoring data of the perihematomal region revealed metabolic distress and increased MMP-9 levels in the brain extracellular fluid during perihematomal edema progression. At the same time, subdural electrocorticography showed clusters of CSDs, which disappeared after ketamine anesthesia on day six. Perihematomal edema regression was associated with decreasing cerebral MMP-9 levels. Conclusions This novel association between clusters of CSDs, brain metabolic distress, and increased MMP-9 levels expands our knowledge about secondary brain injury after ICH. The role of ketamine after this devastating disorder needs further studies.
    Neurocritical Care 08/2014; 22(2). DOI:10.1007/s12028-014-0050-4 · 2.60 Impact Factor
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    ABSTRACT: Background Three-dimensional (3D) culture in porous biomaterials as well as stimulation with growth factors are known to be supportive for intervertebral disc cell differentiation and tissue formation. Unless sophisticated releasing systems are used, however, effective concentrations of growth factors are maintained only for a very limited amount of time in in vivo applications. Therefore, we investigated, if an initial boost with transforming growth factor-beta 1 (TGF-beta 1) is capable to induce a lasting effect of superior cartilaginous differentiation in slightly and severely degenerated human annulus fibrosus (AF) cells.Methods Human AF tissue was harvested during surgical treatment of six adult patients with lumbar spinal diseases. Grading of disc degeneration was performed with magnet resonance imaging. AF cells were isolated and expanded in monolayer culture and rearranged three-dimensionally in a porous biomaterial consisting of stepwise absorbable poly-glycolic acid and poly-(lactic-co-glycolic) acid and a supportive fine net of non-absorbable polyvinylidene fluoride. An initial boost of TGF-beta 1 or TGF-beta 1 and hyaluronan was applied and compared with controls. Matrix formation was assessed at days 7 and 21 by (1) histological staining of the typical extracellular matrix molecules proteoglycan and type I and type II collagens and by (2) real-time gene expression analysis of aggrecan, decorin, biglycan, type I, II, III, and X collagens as well as of catabolic matrix metalloproteinases MMP-2 and MMP-13.ResultsAn initial boost with TGF-beta 1 or TGF-beta 1 and hyaluronan did not enhance the expression of characteristic AF matrix molecules in our 3D culture system. AF cells showed high viability in the progressively degrading biomaterial. Stratification by grade of intervertebral disc degeneration showed that AF cells from both, slightly degenerated, or severely degenerated tissue are capable of significant up-regulations of characteristic matrix molecules in 3D culture. AF cells from severely degenerated tissue, however, displayed significantly lower up-regulations in some matrix molecules such as aggrecan.Conclusions We failed to show a supportive effect of an initial boost with TGF-beta 1 in our 3D culture system. This underlines the need for further investigations on growth factor releasing systems.
    Journal of Orthopaedic Surgery and Research 08/2014; 9(1):73. DOI:10.1186/s13018-014-0073-8 · 1.58 Impact Factor
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    ABSTRACT: Introduction Elevated brain potassium levels ([K+]) are associated with neuronal damage in experimental models. The role of brain extracellular [K+] in patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH) and its association with hemorrhage load, metabolic dysfunction and outcome has not been studied so far. Methods Cerebral microdialysis (CMD) samples from 28 poor grade aSAH patients were analyzed for CMD [K+] for 12 consecutive days after ictus, and time-matched to brain metabolic and hemodynamic parameters as well as corresponding plasma [K+]. Statistical analysis was performed using a generalized estimating equation with an autoregressive function to handle repeated observations of an individual patient. Results CMD [K+] did not correlate with plasma [K+] (Spearman’s ρ = 0.114, P = 0.109). Higher CMD [K+] was associated with the presence of intracerebral hematoma on admission head computed tomography, CMD lactate/pyruvate ratio >40 and CMD lactate >4 mmol/L (P < 0.05). In vitro retrodialysis data suggest that high CMD [K+] was of brain cellular origin. Higher CMD [K+] was significantly associated with poor 3-month outcome, even after adjusting for age and disease severity (P < 0.01). Conclusions The results of this pilot study suggest that brain extracellular [K+] may serve as a biomarker for brain tissue injury in poor-grade aSAH patients. Further studies are needed to elucidate the relevance of brain interstitial K+ levels in the pathophysiology of secondary brain injury after aSAH.
    Critical care (London, England) 06/2014; 18(3):R119. DOI:10.1186/cc13916
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    ABSTRACT: Degenerative disc disease (DDD) of the cervical spine is common after middle age and can cause loss of disc height with painful nerve impingement, bone and joint inflammation. Despite the clinical importance of these problems, in current publications the pathology of cervical disc degeneration has been studied merely from a morphologic view point using magnetic resonance imaging (MRI), without addressing the issue of biological treatment approaches. So far a wide range of endogenously expressed bioactive factors in degenerative cervical disc cells has not yet been investigated, despite its importance for gene therapeutic approaches. Although degenerative lumbar disc cells have been targeted by different biological treatment approaches, the quantities of disc cells and the concentrations of gene therapeutic factors used in animal models differ extremely. These indicate lack of experimentally acquired data regarding disc cell proliferation and levels of target proteins. Therefore, we analysed proliferation and endogenous expression levels of anabolic, catabolic, ant-catabolic, inflammatory cytokines and matrix proteins of degenerative cervical disc cells in three-dimensional cultures. Preoperative MRI grading of cervical discs was used, then grade III and IV nucleus pulposus (NP) tissues were isolated from 15 patients, operated due to cervical disc herniation. NP cells were cultured for four weeks with low-glucose in collagen I scaffold. Their proliferation rates were analysed using 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide. Their protein expression levels of 28 therapeutic targets were analysed using enzyme-linked immunosorbent assay. During progressive grades of degeneration NP cell proliferation rates were similar. Significantly decreased aggrecan and collagen II expressions (P<0.0001) were accompanied by accumulations of selective catabolic and inflammatory cytokines (disintegrin and metalloproteinase with thrombospondin motifs 4 and 5, matrix metalloproteinase 3, interleukin-1β, interleukin-1 receptor) combined with low expression of anti-catabolic factor (metalloproteinase inhibitor 3) (P<0.0001). This study might contribute to inhibit inflammatory catabolism of cervical discs.
    PLoS ONE 05/2014; 9(5):e96870. DOI:10.1371/journal.pone.0096870 · 3.53 Impact Factor
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    ABSTRACT: Recent evidence suggests axonal injury after aneurysmal subarachnoid haemorrhage (aSAH). The microtubule-associated protein, tau, has been shown to be elevated in the cerebrospinal fluid after aSAH, however, brain extracellular tau levels and their relation to long-term neurological and cognitive outcomes have not been investigated. Serial cerebral microdialysis (CMD) samples were collected from 22 consecutive aSAH patients with multimodal neuromonitoring to determine CMD-total-tau by ELISA. CMD-total-tau was analysed considering other brain metabolic parameters, brain tissue oxygen tension (PbtO2), and functional and neuropsychological outcome at 12 months. All outcome models were analysed using generalised estimating equations with an autoregressive working correlation matrix to account for multiple measurements of brain extracellular proteins per subject. CMD-total-tau levels positively correlated with brain extracellular fluid levels of lactate (r=0.40, p<0.001), glutamate (r=0.45, p<0.001), pyruvate (r=0.26, p<0.001), and the lactate-pyruvate ratio (r=0.26, p<0.001), and were higher in episodes of hypoxic (PbtO2<20 mm Hg) brain extracellular lactate elevation (>4 mmol/L) (p<0.01). More importantly, high CMD-total-tau levels were associated with poor functional outcome (modified Rankin Scale ≥4) 12 months after aSAH even after adjusting for disease severity and age (p=0.001). A similar association was found with 3/5 neuropsychological tests indicative of impairments in cognition, psychomotor speed, visual conceptualisation and frontal executive functions at 1 year after aSAH (p<0.01). These results suggest that CMD-total tau may be an important biomarker for predicting long-term outcome in patients with severe aSAH. The value of axonal injury needs further confirmation in a larger patient cohort, preferably combined with advanced imaging techniques.
    Journal of neurology, neurosurgery, and psychiatry 04/2014; DOI:10.1136/jnnp-2013-307326 · 5.58 Impact Factor
  • Stroke 02/2014; 45(3):e49-e49. DOI:10.1161/STROKEAHA.114.004575 · 6.02 Impact Factor
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    ABSTRACT: Over the last decades, spinal fusion has become one of the most important principles in surgical treatment of spinal pathologies. Despite the undoubted benefits of fusion surgery, there are several drawbacks associated with this technique, including adjacent segment degeneration and pseudoarthrosis. Based on biomechanical data, dynamic stabilization of the spine is intended to ameliorate adjacent level degeneration by stabilizing vertebral motion in defined planes and mimicking natural spine movements.In this paper, we review the literature and discuss past and present pedicle-based non-fusion dynamic stabilization devices. Although there is a paucity of high-quality prospective trials, studies have indicated both promising and disappointing results. In comparison to 360° fusion surgery, the perioperative risk seems to be lower. Other complications like screw loosening, however, have been reported with various systems, while a reduction of adjacent segment disease has not yet been demonstrated. The necessary degree of restabilization to achieve pain-free motion seems to vary greatly between patients and current systems are far from perfection. If these problems can be solved, dynamic stabilization may nevertheless be an important option of spinal surgery in the future.
    Advances and technical standards in neurosurgery 01/2014; 41:131-42. DOI:10.1007/978-3-319-01830-0_6
  • Jochen Obernauer, Claudius Thomé
    Neurochirurgie - Handbuch für die Weiterbildung und interdisziplinäres Nachschlagewerk, 2 edited by Dag Moskopp, Hansdetlef Wassmann, 01/2014; Schattauer GmbH Stuttgart., ISBN: 978-3-7945-2442-6
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    ABSTRACT: Painful degenerative disc diseases have been targeted by different biological treatment approaches. Nucleus pulposus (NP) cells play a central role in intervertebral disc (IVD) maintenance by orchestrating catabolic, anabolic and inflammatory factors that affect the extracellular matrix. IVD degeneration is associated with imbalances of these factors, resulting in a catabolic inflammatory metabolism. Therefore, accurate knowledge about their quantity and quality with regard to matrix synthesis is vital for a rational gene therapeutic approach. NP cells were isolated from 63 patients operated due to lumbar disc herniation (mean age 56 / range 29 - 84 years). Then, three-dimensional culture with low-glucose was completed in a collagen type I scaffold for four weeks. Subsequently cell proliferation evaluation was performed using 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide and intracellular concentration of 28 endogenously expressed anabolic, catabolic, inflammatory factors and relevant matrix proteins was determined by enzyme-linked immunosorbent assay. Specimen-related grades of degeneration were confirmed by preoperative magnetic resonance imaging. Independent from gender, age and grade of degeneration proliferation rates remained similar in all groups of NP cells. Progressive grades of degeneration, however, showed a significant influence on accumulation of selective groups of factors such as disintegrin and metalloproteinase with thrombospondin motifs 4 and 5, matrix metalloproteinase 3, metalloproteinase inhibitor 1 and 2, interleukin-1β and interleukin-1 receptor. Along with these changes, the key NP matrix proteins aggrecan and collagen II decreased significantly. The concentration of anabolic factors bone morphogenetic proteins 2, 4, 6 and 7, insulin-like growth factor 1, transforming growth factor beta 1 and 3, however, remained below the minimal detectable quantities. These findings indicate that progressive degenerative changes in NP may be problematic with regard to biologic treatment strategies. Hence, gene therapeutic interventions regulating relevant bioactive factors identified in this work might contribute to the development of regenerative treatment approaches for degenerative disc diseases.
    PLoS ONE 11/2013; 8(11):e81467. DOI:10.1371/journal.pone.0081467 · 3.53 Impact Factor
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    ABSTRACT: Moyamoya disease (MMD) is characterized by unique angiographic features of collateralization. However, a detailed quantification as well as comparative analysis with cerebrovascular atherosclerotic disease (CAD) and healthy controls have not been performed to date. We reviewed 67 patients with MMD undergoing Xenon-enhanced computed tomography, as well as 108 patients with CAD and 5 controls. In addition to cortical, central, and infratentorial regions of interest, particular emphasis was put on regions that are typically involved in MMD (pericallosal territory, basal ganglia). Cerebral blood flow (CBF), cerebrovascular reserve capacity (CVRC), and hemodynamic stress distribution were calculated. MMD is characterized by a significant, ubiquitous decrease in CVRC and a cortical but not pericallosal decrease in CBF when compared with controls. Baseline perfusion is maintained within the basal ganglia, and hemodynamic stress distribution confirmed a relative preservation of central regions of interest in MMD, indicative for its characteristic proximal collateralization pattern. In MMD and CAD, cortical and central CBF decreased significantly with age, whereas CVRC and hemodynamic stress distribution are relatively unaffected by age. No difference in CVRC of comparable regions of interest was seen between MMD and CAD, but stress distribution was significantly higher in MMD, illustrating the functionality of the characteristic rete mirabilis. Our data provide quantitative support for a territory-specific perfusion pattern that is unique for MMD, including central preservation of CBF compared with controls and patients with CAD. This correlates well with its characteristic feature of proximal collateralization. CVRC and hemodynamic stress distribution seem to be more robust parameters than CBF alone for assessment of disease severity.
    Stroke 11/2013; 45(3). DOI:10.1161/STROKEAHA.113.003370 · 6.02 Impact Factor
  • 11/2013; 2013(1):225-238. DOI:10.1055/s-0033-1358827
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    ABSTRACT: Annulus fibrosus repair techniques for the intervertebral disc (IVD) address the unsolved problem of reherniation after IVD herniation and might facilitate the development of nucleus pulposus replacement techniques for IVD diseases. This study investigates the suitability of a bio-integrative annulus implant.Standardized box defects were applied to the annulus L3/4 and L4/5 of 16 sheep, followed by randomized insertion of the textile polyglycolic acid/polyvinylidene fluoride annulus implant in one of the defects. Explantation was conducted after 2, 6 and 12 weeks, followed by provocative pressure testing and histological analysis. At 2 weeks' follow-up, all specimens of the control defect group demonstrated uncontained herniated nucleus pulposus tissue in the annulus defects. For the treated specimens, the annulus implant consistently provided an effective barrier for herniating nucleus pulposus tissue, with no implant dislocation at all time-points. After 2 weeks, a homogeneous cell infiltration of the annulus implant was observed, leading to a progressive directional matrix build-up. Repair tissue thickness was significantly stronger with the annulus implant at all follow-ups (p < 0.01). No pronounced foreign body reaction and no difference in the amount of supra-annular scar tissue over the defect sites were observed. The implantation procedure inflicted annulus damage adjacent to the defect. At later time-points, however, no difference in comparison with the control defect group was evident. The investigated biointegrative annulus implant showed promising results with regard to biointegration, enhancement of repair tissue and function as a mechanical barrier in an ovine model. © 2013 The Authors. Journal of Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd.
    Journal of Tissue Engineering and Regenerative Medicine 11/2013; 9(4). DOI:10.1002/term.1831 · 4.43 Impact Factor
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    ABSTRACT: Study Design. prospective cohort studyObjective. to determine the value of routine postoperative MR imaging early after lumbar decompression in patients with non-specific symptoms.Summary of background data. Imaging after lumbar surgery may be performed more readily even with non-specific symptoms and without neurological deficit.Methods. Patients undergoing elective lumbar decompression surgery completed standardized questionnaires, were assessed neurologically on admission, and underwent MRI scanning within 72h after surgery. Residual stenosis was graded as absent or mild (outcome A) or moderate to severe (outcome B). Surgical technique and intraoperative complications and postoperative neurological status were recorded.Results. We recruited 28 consecutive patients who reported significant improvement of preoperative symptoms. In 2/3 of all patients, postoperative imaging showed at least one segment with moderate or severe residual stenosis (B). Radiological outcome did not correlate with postoperative pain. Patient satisfaction index was comparable in group A and B. The cross section of the spinal canal was significantly wider with a drain in situ. This did not, however, translate into a difference in overall VAS or wound discomfort. Patients tended to report more back and leg pain with drains and were less satisfied with the result of the operation.Conclusions. Early postoperative MR imaging in patients with non-specific symptoms frequently shows radiologically relevant stenosis, which is neither associated with outcome nor patient satisfaction. Drain placement is associated with less radiological narrowing, but with lower patient satisfaction. Imaging without clinical correlate may yield non-discriminatory information likely to unsettle and puzzle both patient and health care provider.
    Spine 09/2013; 38(20):E1263-8. DOI:10.1097/BRS.0b013e31829fc6a6 · 2.45 Impact Factor
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    ABSTRACT: Cerebral revascularization procedures are a treatment option in Moyamoya disease patients, but recent studies failed to show an immediate benefit in cerebrovascular atherosclerotic disease. To facilitate optimal efficacy of the procedure, a detailed characterization of a representative perioperative complication rate and the role of potential risk factors such as underlying pathology, antiplatelet therapy and the type of surgery performed is warranted and the purpose of this study. We included 158 consecutive patients with Moyamoya disease or cerebrovascular atherosclerotic disease undergoing 168 direct revascularization procedures. Type of disease, antiplatelet therapy, coagulation disorders, surgical technique, intraoperative complications, postoperative imaging, the need for revision and outcome at time of discharge were analyzed. Complication rate was low with a high patency rate of 97%. Six hemispheres (3.6%) needed to undergo surgical revision, early morbidity was 10.7% with no mortality, with evidence of ischemia in 6.9% of patients. Type of pathology treated and surgical technique did not influence outcome. Antiplatelet treatment was not associated with an increased risk for hemorrhage or revision, but improved outcome (p<0.05). Ischemia, hemorrhage and the need for revision aggravated outcome at time of discharge. EC-IC bypass surgery remains a treatment option in patients with Moyamoya disease, while its use in the context of atherosclerotic disease was recently put into question. Regardless, a detailed characterization of perioperative risk factors is needed to optimize a potential longterm benefit of surgery. At a high-volume center, the complication rate is low independent from the underlying pathology with a high patency rate. Antiplatelet treatment does not increase the risk of hemorrhagic complications, but may improve outcome. Longer follow-up is required to adequately assess the true efficacy of revascularization on stroke prevention.
    World Neurosurgery 07/2013; 82(5). DOI:10.1016/j.wneu.2013.06.010 · 2.42 Impact Factor

Publication Stats

2k Citations
279.91 Total Impact Points

Institutions

  • 2010–2015
    • University of Innsbruck
      • Institute of Analytical Chemistry and Radiochemistry
      Innsbruck, Tyrol, Austria
  • 2012
    • Charité Universitätsmedizin Berlin
      Berlín, Berlin, Germany
  • 2000–2011
    • Universität Heidelberg
      Heidelburg, Baden-Württemberg, Germany
  • 2003–2010
    • Universität Mannheim
      Mannheim, Baden-Württemberg, Germany