Assessment of a Reliable Fractional Anisotropy Cutoff in Tractography of the Corticospinal Tract for Neurosurgical Patients

Background: Tractography has become a standard technique for planning neurosurgical operations in the past decades. This technique relies on diffusion magnetic resonance imaging. The cutoff value for the fractional anisotropy (FA) has an important role in avoiding false-positive and false-negative results. However, there is a wide variation in FA cutoff values. Methods: We analyzed a prospective cohort of 14 patients (six males and eight females, 50.1 ± 4.0 years old) with intracerebral tumors that were mostly gliomas. Magnetic resonance imaging (MRI) was obtained within 7 days before and within 7 days after surgery with T1 and diffusion tensor image (DTI) sequences. We, then, reconstructed the corticospinal tract (CST) in all patients and extracted the FA values within the resulting volume. Results: The mean FA in all CSTs was 0.4406 ± 0.0003 with the fifth percentile at 0.1454. FA values in right-hemispheric CSTs were lower (p < 0.0001). Postoperatively, the FA values were more condensed around their mean (p < 0.0001). The analysis of infiltrated or compressed CSTs revealed a lower fifth percentile (0.1407 ± 0.0109 versus 0.1763 ± 0.0040, p = 0.0036). Conclusion: An FA cutoff value of 0.15 appears to be reasonable for neurosurgical patients and may shorten the tractography workflow. However, infiltrated fiber bundles must trigger vigilance and may require lower cutoffs

Usefulness and Limits of Tractography for Surgery in the Precentral Gyrus: A Case Report

The resection of tumors within the primary motor cortex is a constant challenge. Although tractography may help in preoperative planning, it has limited application. While it can give valuable information on subcortical fibers, it is less accurate in the cortical layer of the brain. A 38-year-old patient presented with paresis of the right hand and focal epileptic seizures due to a tumor in the left precentral gyrus. Transcranial magnetic stimulation was not applicable due to seizures, so microsurgical resection was performed with preoperative tractography and intraoperative direct electrical stimulation. A histopathological assessment revealed a diagnosis of glioblastoma. Postoperative magnetic resonance imaging (MRI) showed complete resection. The paresis dissolved completely during follow-up. Surgery within the precentral gyrus is of high risk and requires multimodal functional planning. If interpreted with vigilance and consciousness of the underlying physical premises, tractography can provide helpful information within its limitations, which is especially subcortically. However, it may also help in the identification of functional cortex columns of the brain in the presence of a tumor

In situ impedance measurements on postmortem porcine brain

The paper presents an experimental study where the distinctness of grey and white matter of an in situ postmortem porcine brain by impedance measurements is investigated. Experimental conditions that would allow to conduct the same experiment on in vivo human brain tissue are replicated

The Prognostic Value of NANO Scale Assessment in IDH-Wild-Type Glioblastoma Patients

Background: IDH-wild-type glioblastoma (GBM) is the most frequent brain-derived malignancy. Despite intense research efforts, it is still associated with a very poor prognosis. Several parameters were identified as prognostic, including general physical performance. In neuro-oncology (NO), special emphasis is put on focal deficits and cognitive (dys-)function. The Neurologic Assessment in Neuro-Oncology (NANO) scale was proposed in order to standardize the assessment of neurological performance in NO. This study evaluated whether NANO scale assessment provides prognostic information in a standardized collective of GBM patients. Methods: The records of all GBM patients treated between 2014 and 2019 at our facility were retrospectively screened. Inclusion criteria were age over 18 years, at least 3 months postoperative follow-up, and preoperative and postoperative cranial magnetic resonance imaging. The NANO scale was assessed pre- and postoperatively as well as at 3 months follow-up. Univariate and multivariate survival analyses were carried to investigate the prognostic value. Results: One hundred and thirty-one patients were included. In univariate analysis, poor postoperative neurological performance (HR 1.13, p = 0.004), poor neurological performance at 3 months postsurgery (HR 1.37, p < 0.001), and neurological deterioration during follow-up (HR 1.38, p < 0.001), all assessed via the NANO scale, were associated with shorter survival. In multivariate analysis including other prognostic factors such as the extent of resection, adjuvant treatment regimen, or age, NANO scale assessment at 3 months postoperative follow-up was independently associated with survival prediction (HR 1.36, p < 0.001). The optimal NANO scale cutoff for patient stratification was 3.5 points. Conclusion: Neurological performance assessment employing the NANO scale might provide prognostic information in patients suffering from GBM

Die Rolle der SK-Kanäle in alpha-Synuclein-aktivierter primärer Mikroglia

Hintergrund: Die Parkinson-Erkrankung gehört zu den weltweit häufigsten neurodegenerati-ven Krankheiten und ist die häufigste Bewegungsstörung beim Menschen. In der jüngeren Vergangenheit wurde α-Synuclein als möglicher Auslöser der Parkinsonkrankheit identifiziert. Seit einigen Jahren wird die Rolle der Mikroglia in neurodegenerativen Krankheiten diskutiert. Sie stehen im Verdacht, im Rahmen einer überschießenden Entzündungsreaktion Neurone zu schädigen und so zur Pathogenese beizutragen. Hypothese: Der spezifische Wirkstoff CyPPA kann SK-Kanäle selektiv öffnen. Wie zuvor in anderen Modellsystemen gezeigt werden konnte, führt dies zu einer Verringerung der inflammatorischen Antwort der Mikroglia. Wir vermuten eine ähnliche Wirkung auch in einem Modellsystem, das α-Synuclein als Induktor mikroglialer Inflammation verwendet. Mit α-Synuclein aktivierte Mikroglia sollten sich also hinsichtlich ihrer inflammatorischen Antwort durch CyPPA positiv beeinflussen lassen und die Entzündungsreaktion verringert werden. Methoden: Wir gewannen Mikroglia aus postnatalen Mäusen und legten Primärkulturen an. Diese behandelten wir mit α-Synuclein, um sie proinflammatorisch zu aktivieren. Als Endpunkte der inflammatorischen Antwort bestimmten wir die Proliferation mittels Impedanzmessungen. Zellmorphologische Veränderungen wurden durch Immunfluoreszenz bildgebend dargestellt. Die proinflammatorische Antwort im Hinblick auf ausgeschüttete Mediatoren wurde anhand der produzierten Zytokine (IL-6, IL1β, TNF-α) analysiert. In einem zweiten Schritt erfolgte die gleichzeitige, Vor- und Nachbehandlung dieser aktivierten Kulturen mit CyPPA. Die Reduktion der inflammatorischen Antwort wurde ebenfalls anhand der oben genannten Parameter evaluiert. Ergebnisse: Die Studie zeigt, dass die selektive Beeinflussung der SK-Kanäle zu einem signifikanten Rückgang α-Synuclein-vermittelter mikroglialer Aktivierung führt. Hierbei zeigte sich sowohl eine Reduktion der Proliferation und der Ausschüttung von Entzündungsmediatoren, als auch eine geringere Veränderung der Zellmorphologie. Die α -Synuclein-vermittelte Aktivierung von Mikroglia als Modell der Inflammation in PD konnte etabliert werden. Schlussfolgerung: Der SK-Kanal-Modulator CyPPA reduziert in vitro die inflammatorische Antwort von Mikroglia in einem Parkinson-Modell. Sollte dieser Effekt in der Übertragung auf Co-Kultursysteme bestand haben und eine geringere Schädigung primärer Neurone durch eine überschießende Immunreaktion zur Folge haben, sind sie damit ein potentielles pharmakologisches Agens in der Behandlung der Parkinsonkrankheit

Die Rolle der SK-Kanäle in alpha-Synuclein-aktivierter primärer Mikroglia

Hintergrund: Die Parkinson-Erkrankung gehört zu den weltweit häufigsten neurodegenerati-ven Krankheiten und ist die häufigste Bewegungsstörung beim Menschen. In der jüngeren Vergangenheit wurde α-Synuclein als möglicher Auslöser der Parkinsonkrankheit identifiziert. Seit einigen Jahren wird die Rolle der Mikroglia in neurodegenerativen Krankheiten diskutiert. Sie stehen im Verdacht, im Rahmen einer überschießenden Entzündungsreaktion Neurone zu schädigen und so zur Pathogenese beizutragen. Hypothese: Der spezifische Wirkstoff CyPPA kann SK-Kanäle selektiv öffnen. Wie zuvor in anderen Modellsystemen gezeigt werden konnte, führt dies zu einer Verringerung der inflammatorischen Antwort der Mikroglia. Wir vermuten eine ähnliche Wirkung auch in einem Modellsystem, das α-Synuclein als Induktor mikroglialer Inflammation verwendet. Mit α-Synuclein aktivierte Mikroglia sollten sich also hinsichtlich ihrer inflammatorischen Antwort durch CyPPA positiv beeinflussen lassen und die Entzündungsreaktion verringert werden. Methoden: Wir gewannen Mikroglia aus postnatalen Mäusen und legten Primärkulturen an. Diese behandelten wir mit α-Synuclein, um sie proinflammatorisch zu aktivieren. Als Endpunkte der inflammatorischen Antwort bestimmten wir die Proliferation mittels Impedanzmessungen. Zellmorphologische Veränderungen wurden durch Immunfluoreszenz bildgebend dargestellt. Die proinflammatorische Antwort im Hinblick auf ausgeschüttete Mediatoren wurde anhand der produzierten Zytokine (IL-6, IL1β, TNF-α) analysiert. In einem zweiten Schritt erfolgte die gleichzeitige, Vor- und Nachbehandlung dieser aktivierten Kulturen mit CyPPA. Die Reduktion der inflammatorischen Antwort wurde ebenfalls anhand der oben genannten Parameter evaluiert. Ergebnisse: Die Studie zeigt, dass die selektive Beeinflussung der SK-Kanäle zu einem signifikanten Rückgang α-Synuclein-vermittelter mikroglialer Aktivierung führt. Hierbei zeigte sich sowohl eine Reduktion der Proliferation und der Ausschüttung von Entzündungsmediatoren, als auch eine geringere Veränderung der Zellmorphologie. Die α -Synuclein-vermittelte Aktivierung von Mikroglia als Modell der Inflammation in PD konnte etabliert werden. Schlussfolgerung: Der SK-Kanal-Modulator CyPPA reduziert in vitro die inflammatorische Antwort von Mikroglia in einem Parkinson-Modell. Sollte dieser Effekt in der Übertragung auf Co-Kultursysteme bestand haben und eine geringere Schädigung primärer Neurone durch eine überschießende Immunreaktion zur Folge haben, sind sie damit ein potentielles pharmakologisches Agens in der Behandlung der Parkinsonkrankheit

Assessment of a Reliable Fractional Anisotropy Cutoff in Tractography of the Corticospinal Tract for Neurosurgical Patients

Background: Tractography has become a standard technique for planning neurosurgical operations in the past decades. This technique relies on diffusion magnetic resonance imaging. The cutoff value for the fractional anisotropy (FA) has an important role in avoiding false-positive and false-negative results. However, there is a wide variation in FA cutoff values. Methods: We analyzed a prospective cohort of 14 patients (six males and eight females, 50.1 ± 4.0 years old) with intracerebral tumors that were mostly gliomas. Magnetic resonance imaging (MRI) was obtained within 7 days before and within 7 days after surgery with T1 and diffusion tensor image (DTI) sequences. We, then, reconstructed the corticospinal tract (CST) in all patients and extracted the FA values within the resulting volume. Results: The mean FA in all CSTs was 0.4406 ± 0.0003 with the fifth percentile at 0.1454. FA values in right-hemispheric CSTs were lower (p &lt; 0.0001). Postoperatively, the FA values were more condensed around their mean (p &lt; 0.0001). The analysis of infiltrated or compressed CSTs revealed a lower fifth percentile (0.1407 ± 0.0109 versus 0.1763 ± 0.0040, p = 0.0036). Conclusion: An FA cutoff value of 0.15 appears to be reasonable for neurosurgical patients and may shorten the tractography workflow. However, infiltrated fiber bundles must trigger vigilance and may require lower cutoffs

Assessment of a Reliable Fractional Anisotropy Cutoff in Tractography of the Corticospinal Tract for Neurosurgical Patients

Background: Tractography has become a standard technique for planning neurosurgical operations in the past decades. This technique relies on diffusion magnetic resonance imaging. The cutoff value for the fractional anisotropy (FA) has an important role in avoiding false-positive and false-negative results. However, there is a wide variation in FA cutoff values. Methods: We analyzed a prospective cohort of 14 patients (six males and eight females, 50.1 ± 4.0 years old) with intracerebral tumors that were mostly gliomas. Magnetic resonance imaging (MRI) was obtained within 7 days before and within 7 days after surgery with T1 and diffusion tensor image (DTI) sequences. We, then, reconstructed the corticospinal tract (CST) in all patients and extracted the FA values within the resulting volume. Results: The mean FA in all CSTs was 0.4406 ± 0.0003 with the fifth percentile at 0.1454. FA values in right-hemispheric CSTs were lower (p < 0.0001). Postoperatively, the FA values were more condensed around their mean (p < 0.0001). The analysis of infiltrated or compressed CSTs revealed a lower fifth percentile (0.1407 ± 0.0109 versus 0.1763 ± 0.0040, p = 0.0036). Conclusion: An FA cutoff value of 0.15 appears to be reasonable for neurosurgical patients and may shorten the tractography workflow. However, infiltrated fiber bundles must trigger vigilance and may require lower cutoffs

Tinzaparin vs. Nadroparin Safety and Efficacy in Neurosurgery

Background: An outbreak of African swine fever (ASF) in China in 2020 has led to an unprecedented shortage of nadroparin. Most patients, especially those kept in hospital for surgery, are currently treated with prophylactic anticoagulation (AC). In search of alternatives for nadroparin (fraxiparine), we found no sufficient data on alternatives for neurosurgical patients, such as tinzaparin of European origin. We compared nadroparin and tinzaparin concerning adverse events (bleeding versus thromboembolic events) in neurosurgical patients. Methods: Between 2012 and 2018, 517 neurosurgical patients with benign and malignant brain tumors as well as 297 patients with subarachnoid hemorrhage (SAH) were treated in the Department of Neurosurgery, University Hospital Leipzig, receiving prophylactic anticoagulation within 48 h. In 2015, prophylactic anticoagulation was switched from nadroparin to tinzaparin throughout the university hospital. In a retrospective manner, the frequency and occurrence of adverse events (rebleeding and thromboembolic events) in connection with the substance used were analyzed. Statistical analysis was performed using Fisher’s exact test and the chi-squared test. Results: Rebleeding rates were similar in both nadroparin and tinzaparin cohorts in patients being treated for meningioma, glioma, and SAH combined (8.8% vs. 10.3%). Accordingly, the rates of overall thromboembolic events were not significantly different (5.5% vs. 4.3%). The severity of rebleeding did not vary. There was no significant difference among subgroups when compared for deep vein thrombosis (DVT) or pulmonary embolism (PE). Conclusion: In this retrospective study, tinzaparin seems to be a safe alternative to nadroparin for AC in patients undergoing brain tumor surgery or suffering from SAH

Tinzaparin vs. Nadroparin Safety and Efficacy in Neurosurgery

Background: An outbreak of African swine fever (ASF) in China in 2020 has led to an unprecedented shortage of nadroparin. Most patients, especially those kept in hospital for surgery, are currently treated with prophylactic anticoagulation (AC). In search of alternatives for nadroparin (fraxiparine), we found no sufficient data on alternatives for neurosurgical patients, such as tinzaparin of European origin. We compared nadroparin and tinzaparin concerning adverse events (bleeding versus thromboembolic events) in neurosurgical patients. Methods: Between 2012 and 2018, 517 neurosurgical patients with benign and malignant brain tumors as well as 297 patients with subarachnoid hemorrhage (SAH) were treated in the Department of Neurosurgery, University Hospital Leipzig, receiving prophylactic anticoagulation within 48 h. In 2015, prophylactic anticoagulation was switched from nadroparin to tinzaparin throughout the university hospital. In a retrospective manner, the frequency and occurrence of adverse events (rebleeding and thromboembolic events) in connection with the substance used were analyzed. Statistical analysis was performed using Fisher’s exact test and the chi-squared test. Results: Rebleeding rates were similar in both nadroparin and tinzaparin cohorts in patients being treated for meningioma, glioma, and SAH combined (8.8% vs. 10.3%). Accordingly, the rates of overall thromboembolic events were not significantly different (5.5% vs. 4.3%). The severity of rebleeding did not vary. There was no significant difference among subgroups when compared for deep vein thrombosis (DVT) or pulmonary embolism (PE). Conclusion: In this retrospective study, tinzaparin seems to be a safe alternative to nadroparin for AC in patients undergoing brain tumor surgery or suffering from SAH