Journal: Acta Neurochirurgica

Abbreviation

Acta Neurochir

Publisher

Springer

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ISSN

0001-6268
0942-0940

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Publications1 - 9 of 9
  • Comparison of anti-siphon devices - How do they affect CSF dynamics in supine and upright posture?
    Item type: Journal Article
    Gehlen, Manuel; Eklund, Anders; Kurtcuoglu, Vartan; et al. (2017)
    Acta Neurochirurgica
    Background Three different types of anti-siphon devices (ASDs) have been developed to counteract siphoning-induced overdrainage in upright posture. However, it is not known how the different ASDs affect CSF dynamics under the complex pressure environment seen in clinic due to postural changes. We investigated which ASDs can avoid overdrainage in upright posture best without leading to CSF accumulation. Methods Three shunts each of the types Codman Hakim with SiphonGuard (flow-regulated), Miethke miniNAV with proSA (gravitational), and Medtronic Delta (membrane controlled) were tested. The shunts were compared on a novel in vitro setup that actively emulates the physiology of a shunted patient. This testing method allows determining the CSF drainage rates, resulting CSF volume, and intracranial pressure in the supine, sitting, and standing posture. Results The flow-regulated ASDs avoided increased drainage by closing their primary flow path when drainage exceeded 1.39 ± 0.42 mL/min. However, with intraperitoneal pressure increased in standing posture, we observed reopening of the ASD in 3 out of 18 experiment repetitions. The adjustable gravitational ASDs allow independent opening pressures in horizontal and vertical orientation, but they did not provide constant drainage in upright posture (0.37 ± 0.03 mL/min and 0.26 ± 0.03 mL/min in sitting and standing posture, respectively). Consequently, adaptation to the individual patient is critical. The membrane-controlled ASDs stopped drainage in upright posture. This eliminates the risk of overdrainage, but leads to CSF accumulation up to the volume observed without shunting when the patient is upright. Conclusions While all tested ASDs reduced overdrainage, their actual performance will depend on a patient’s specific needs because of the large variation in the way the ASDs influence CSF dynamics: while the flow-regulated shunts provide continuous drainage in upright posture, the gravitational ASDs allow and require additional adaptation, and the membrane-controlled ASDs show robust siphon prevention by a total stop of drainage.
  • Biomechanical comparison of sagittal-parallel versus non-parallel pedicle screw placement
    Item type: Journal Article
    Farshad, Mazda; Farshad-Amacker, Nadja A.; Bachmann, Elias; et al. (2014)
    Acta Neurochirurgica
    Background While convergent placement of pedicle screws in the axial plane is known to be more advantageous biomechanically, surgeons intuitively aim toward a parallel placement of screws in the sagittal plane. It is however not clear whether parallel placement of screws in the sagittal plane is biomechanically superior to a non-parallel construct. The hypothesis of this study is that sagittal non-parallel pedicle screws do not have an inferior initial pull-out strength compared to parallel placed screws. Methods The established lumbar calf spine model was used for determination of pull-out strength in parallel and non-parallel intersegmental pedicle screw constructs. Each of six lumbar calf spines (L1-L6) was divided into three levels: L1/L2, L3/L4 and L5/L6. Each segment was randomly instrumented with pedicle screws (6/45 mm) with either the standard technique of sagittal parallel or non-parallel screw placement, respectively, under fluoroscopic control. CT was used to verify the intrapedicular positioning of all screws. The maximum pull-out forces and type of failure were registered and compared between the groups. Results The pull-out forces were 5,394 N (range 4,221 N to 8,342 N) for the sagittal non-parallel screws and 5,263 N (range 3,589 N to 7,554 N) for the sagittal-parallel screws (p = 0.838). Interlevel comparisons also showed no statistically significant differences between the groups with no relevant difference in failure mode. Conclusion Non-parallel pedicle screws in the sagittal plane have at least equal initial fixation strength compared to parallel pedicle screws in the setting of the here performed cadaveric calf spine experiments.
  • A new subdural probe for combined intracranial pressure (ICP) and cerebral blood flow (CBF) monitoring
    Item type: Journal Article
    Keller, E.; Nadler, A.; Niederer, P.; et al. (2003)
    Acta Neurochirurgica
  • A basic model for training of microscopic and endoscopic transsphenoidal pituitary surgery: the Egghead
    Item type: Journal Article
    Engel, Doortje C.; Ferrari, Andrea; Tasman, Abel-Jan; et al. (2015)
    Acta Neurochirurgica
  • Flow diversion treatment
    Item type: Journal Article
    Kulcsár, Zsolt; Augsburger, Luca; Reymond, Philippe; et al. (2012)
    Acta Neurochirurgica
  • Expanding applications of deep brain stimulation
    Item type: Review Article
    Halpern, Casey H.; Torres, Napoleon; Hurtig, Howard I.; et al. (2011)
    Acta Neurochirurgica
  • Introducing e-Motions: a novel intraoperative test for social cognition mapping. Triple validation in normative, schizophrenia, and autism spectrum disorder populations
    Item type: Journal Article
    Martín-Fernández , Jesús; Caballero-Estebaranz , Nayra; Félez , Esteban; et al. (2025)
    Acta Neurochirurgica
    Background Social cognition is essential for daily functioning, as it influences quality of life, return to work, and interpersonal communication. While schizophrenia and autism spectrum disorder (ASD) have been the paradigmatic conditions in which social cognition is markedly impaired, emerging evidence suggests that up to 30% patients with brain tumors may experience persistent deficits in this domain. Despite its clinical relevance, social cognition remains insufficiently studied in neuro-oncology and lacks dedicated intraoperative assessment tools specifically tailored for its use during awake brain surgery. Method This study introduces e-Motions, a new test designed ad hoc to address this gap. The e-Motions test comprises 34 four-second video stimuli depicting two hyper-realistic avatars (one male, one female) expressing complex emotions. These avatars were developed using an AI-based facial motion capture system applied to 60 professional actors. Validation was performed in three groups: (1) healthy adults (n = 226), (2) individuals with schizophrenia (n = 33), and (3) ASD (n = 30). Results Internal consistency (KR-20), test–retest reliability (ICC), and correlations with established social cognition tools (Reading the Mind in the Eyes [RMET], Ekman-60 faces test [Ekman-60F], and the Movie for the Assessment of Social Cognition [MASC]) were evaluated. The e-Motions test demonstrated high global internal consistency (KR-20 = 0.86) and good test–retest reliability (ICC₂,₁ = 0.73). Scores showed positive moderate correlations with both lower-level mentalizing tests (RME: ρ = 0.44; Ekman-60F: ρ = 0.48) and higher-level mentalizing test (MASC: ρ = 0.57). Discriminative power was strong for distinguishing healthy participants from individuals with schizophrenia (AUC = 0.89) and ASD (AUC = 0.79). Conclusions e-Motions test is the first AI-based test created ad hoc for awake brain mapping. Its good internal consistency and significant correlation with low-level and high-level mentalizing tests make this tool a novel, ecological and promising way to identify critical regions involved in social cognition during awake brain mapping. Future studies should be performed to demonstrate its validity preserving this complex higher-order cognitive construct during and after brain tumor surgery.
  • Neurologists, neurosurgeons, and psychiatrists' personality traits: a comparison
    Item type: Journal Article
    Surbeck, Werner; Samuel, Robin; Spieler, Derek; et al. (2020)
    Acta Neurochirurgica
  • Air travel with pneumocephalus: a systematic review
    Item type: Review Article
    Bichsel, Oliver; Hauck, Annalisa; Oertel, Markus (2022)
    Acta Neurochirurgica
    Introduction Concerns arise when patients with pneumocephalus engage in air travel. How hypobaric cabin pressure affects intracranial air is largely unclear. A widespread concern is that the intracranial volume could relevantly expand during flight and lead to elevated intracranial pressure. The aim of this systematic review was to identify and summarise models and case reports with confirmed pre-flight pneumocephalus. Methods The terms (pneumocephalus OR intracranial air) AND (flying OR fly OR travel OR air transport OR aircraft) were used to search the database PubMed on 30 November 2021. This search returned 144 results. To be included, a paper needed to fulfil each of the following criteria: (i) peer-reviewed publication of case reports, surveys, simulations or laboratory experiments that focussed on air travel with pre-existing pneumocephalus; (ii) available in full text. Results Thirteen studies met the inclusion criteria after title or abstract screening. We additionally identified five more articles when reviewing the references. A notion that repeatedly surfaced is that any air contained within the neurocranium increases in volume at higher altitude, much like any extracranial gas, potentially resulting in tension pneumocephalus or increased intracranial pressure. Discussion Relatively conservative thresholds for patients flying with pneumocephalus are suggested based on models where the intracranial air equilibrates with cabin pressure, although intracranial air in a confined space would be surrounded by the intracranial pressure. There is a discrepancy between the models and case presentations in that we found no reports of permanent or transient decompensation secondary to a pre-existing pneumocephalus during air travel. Nevertheless, the quality of examination varies and clinicians might tend to refrain from reporting adverse events. We identified a persistent extracranial to intracranial fistulous process in multiple cases with newly diagnosed pneumocephalus after flight. Finally, we summarised management principles to avoid complications from pneumocephalus during air travel and argue that a patient-specific understanding of the pathophysiology and time course of the pneumocephalus are potentially more important than its volume.
Publications1 - 9 of 9