Sektionstage Frühjahr 2025 der Deutschen Gesellschaft für Neurochirurgie

Prof. Dr. med.

Prof. Dr.

Dr. med.

Clinical Relevance of Interictal PET and SPECT in Localizing Epileptogenic Foci for Surgical PlanningKlinische Relevanz von interiktalem PET und SPECT bei der Lokalisierung epileptogener Herde für die chirurgische Planung

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What is the clinical relevance of interictal PET and SPECT in localizing the seizure onset zone (SOZ) in patients with mesial temporal sclerosis (MTS) and drug-resistant epilepsy (DRE), and how do these imaging modalities influence surgical outcomes when combined with positive VEEG and MRI findings?A retrospective analysis was conducted on 60 patients who underwent SPECT and 49 who underwent PET, comparing the results with VEEG and MRI. Key variables included seizure type, epileptogenic foci identified by SPECT and PET, and Engel outcomes at the latest follow-up. Kendall"s tau and Krippendorf's alpha tests assessed imaging agreement. Logistic regression was used to identify variables associated with SOZ localization and Engel I outcomes.PET identified the epileptogenic lesion in 87.8% of cases, compared to 85% for SPECT. PET showed a stronger correlation with VEEG and MRI (τb = 0.713 for both, p < 0.001) and greater concordance (α = 0.8171) compared to SPECT (τb = 0.536 for both, p < 0.001; α = 0.6999). Adding one second to the ictal phase in VEEG increased the likelihood of detecting the SOZ by 1.02 times (p = 0.009). Concordance between three neuroimaging modalities improved the probability of optimal surgical success (Engel I) by eight times (p = 0.041).Interictal PET and SPECT improve SOZ localization in MTS patients, contributing to better surgical outcomes. PET showed slightly higher sensitivity, correlation, and concordance, highlighting the importance of multimodal imaging in the presurgical evaluation of DRE.

Klinische Relevanz von interiktalem PET und SPECT bei der Lokalisierung epileptogener Herde für die chirurgische Planung

Sektion Funktionelle Neurochirurgie:

Abstractvortrag

Implantation of SEEG Electrodes Using Mobile Intraoperative AIRO-CT

Stereoelectroencephalography (SEEG) is an essential invasive diagnostic tool used to localize the epileptic zone in patients with medically refractory focal epilepsy. Traditionally, frame-based stereotactic procedures require a stereotactic CT scan performed with the frame fixed on the patient's skull. This approach often necessitates transfers of intubated patients to imaging facilities, which are complex and require systematic patient-safety work. To address these challenges, we implemented the intraoperative use of the mobile AIRO-CT, which is widely used for navigated spinal surgery, to enable SEEG electrode implantation without patient transport outside the operating room.Trajectory data (planned trajectories and postoperative localization of electrodes) from 10 patients undergoing frame-based stereotactic implantation of SEEG electrodes were analyzed. A total of 62 SEEG electrodes were implanted using the intraoperative AIRO-CT and assessed through postoperative CT on the same day. Euclidean distances (√((xp - xa)² + (yp - ya)² + (zp - za)²)) between the planned and actual (intracranial) entry/target points were calculated to evaluate implantation accuracy.The average patient age was 38.1 years, with seven females. Underlying conditions included six cases of non-lesional focal temporal lobe epilepsy, two cases of focal cortical dysplasia (FCD), one case of tuberous sclerosis, and one case of embolized arteriovenous malformation. The mean Euclidean distances between the planned and actual entry points and target points were 1.81 mm (SD 1.02) and 2.11 mm (SD 1.08), respectively. The average planned and actual trajectory lengths were 36.53 mm and 36.49 mm. All invasive recordings provided relevant information for subsequent therapy planning, leading to selective amygdalohippocampectomy or temporal lobe resection in four cases and extended lesionectomy in three cases. Due to the bitemporal origin of seizures recorded by SEEG, a resective approach was not feasible in two cases. Routine postoperative CT revealed electrode-associated intracranial bleeding in one patient.The intraoperative use of AIRO-CT achieved implantation accuracy comparable to published results of frame-based SEEG electrode implantations with fixed CT scanners and exceeded the accuracy of frameless implantation systems. The AIRO-CT system facilitates all procedural steps within the OR, enhancing workflow efficiency and minimizing patient safety risks associated with transport.

PD Dr.

Diagnostic Yield and Complications in Frame-based Stereotactic Biopsies – Analysis of 622 consecutive patientsDiagnostische Erfolgsrate und Komplikationen rahmenbasierter stereotaktischer Biopsien - Eine Analyse von 622 PatientInnen

Frame-based stereotactic brain biopsy is a reliable technique for obtaining tissue samples from intracranial lesions, essential for integrated molecular and histopathological diagnoses, particularly in cases unsuitable for resection. Despite advances in imaging, significant discrepancies between radiological and histopathological diagnoses persist. Although generally safe, rare but serious complications may occur. This study evaluates the safety, diagnostic accuracy, and complications of frame-based stereotactic brain biopsy, focusing on lesion location and radiological features.A retrospective analysis of our stereotactic database was conducted for the period 2015–2023. N= 622 patients who underwent stereotactic biopsy for unclear brain lesions were included. Neuropathological, surgical, radiological, and clinical follow-up data was analyzed regarding diagnostic yield and complications.The overall diagnostic yield was 88.9%, with glioblastoma (48.6%) and lymphoma (19.6%) being the most common diagnoses. A concordance rate of 75.1% was found between the suspected diagnoses and the final molecular and histological diagnoses. Diagnostic yield was positively associated with the suspected diagnoses of "lymphoma", "glioma,", the presence of necrosis and contrast enhancement in presurgical imaging. Negative associations were observed for the suspected entities "inflammatory processes", "unclear lesion", non-enhancing lesions and lesions located in the occipital lobe. Complications were identified in 61 cases (9.8%), predominantly presenting as neurological deterioration (48 cases, 7.7%), which was temporary in 25 cases (4.0%) and permanent in 23 cases (3.7%). New Neurological deterioration was associated with post-surgical hemorrhage in 50% of the cases (n=24, 32.0 % temporary deterioration, 69.9% permanent deterioration). Other complications were surgical site infections (n=4), wound healing disorders (n=8), and seizures (n=6). 30-day mortality rate was 3.4%, a direct relation with surgery-was found in 3 cases (0.5%).Frame-based stereotactic brain biopsy for unclear CNS lesions is a reliable neurosurgical procedure with a high diagnostic yield. The diagnostic outcome is influenced by the suspected diagnosis and radiological features, underscoring the importance of precise clinical questions. Although complications are rare, neurological deterioration is the most common adverse event, warranting careful risk-benefit evaluation in clinical decision-making.

Diagnostische Erfolgsrate und Komplikationen rahmenbasierter stereotaktischer Biopsien - Eine Analyse von 622 PatientInnen

Prof.Dr.

The rise of functional stereotactic neurosurgery in the realm of a newly born republicDie Anfänge der Stereotaktischen Neurochirurgie in Freiburg und ihre Implikation für die Stereotaktische Neurochirurgie in Deutschland

The main purpose of this article is to report on the life, work and achievements of functional neurosurgeons, neurologists, psychiatrists and neuroanatomists located in Freiburg in the era of the newly founded Federal Republic of Germany along with the depiction of their long-lasting impact for functional stereotactic neurosurgery in Germany and abroad.Review of available literature and personal records (e.g. communications, biographical reports) was assessed and summarized providing an overview of the Freiburg School of Stereotaxy including the main protagonists Traugott Riechert (1905-1983), Rolf Hassler (1914-1984), Fritz Mundinger (1924-2012), Kurt Beringer (1893-1949) and Richard Jung (1911-1986) covering the years around 1950.The rise of stereotactic functional neurosurgery after World War II, was inaugurated mainly by the Department of Neurosurgery in Freiburg through an interplay across neuro-associated disciplines. Close by working relationships between neurosurgery (Traugott Riechert, Fritz Mundinger), neurology/psychiatry/neurophysiology (Kurt Beringer, Richard Jung) and neuroanatomy (Rolf Hassler) enabled the foundation, implementation and further development of stereotactic techniques targeting movement disorders, psychiatric indication, pain, epilepsy and brain tumors. Furthermore, educational efforts were underwent to provide state of the art stereotactic neurosurgery, which led to the spread of the so-called Freiburg School of Stereotaxy throughout Germany (Gert Dieckmann 1925-2007; Fritz Roeder 1906-1988 / Hans Orthner 1914-2000; Konrad Nittner 1921-1994; Wilhelm Umbach 1915-1976) (Fig. 1).The fate and work of the protagonists presented herein underlines the eminent role of the Freiburg School of Stereotaxy for the development and maintenance of functional stereotactic neurosurgery in Germany. This accounts for the broad range of treated neurological disorders along with the passion to steadily strive for innovations and education displayed by the below dissemination of stereotactic functional neurosurgeons across german universities ultimately leading to an increased numbers of stand-alone functional units and/or departments over the coming decades of the past century.

Die Anfänge der Stereotaktischen Neurochirurgie in Freiburg und ihre Implikation für die Stereotaktische Neurochirurgie in Deutschland

Segmentation and structural connectivity of the Putamen for targeted Convection Enhanced Drug Delivery in Parkinson"s Disease: A tractography-based approach

Convection-enhanced drug delivery (CED) for Parkinson's disease (PD) is costly, and current methods lack precision, often targeting the entire putamen, leading to potential inefficient use of resources. Our study proposes a targeted approach, which could reduce treatment costs by focusing therapy on specific regions of putamen. By optimising drug delivery, we aim to make treatments more cost-effective without compromising efficacy.Twenty PD patients underwent diffusion-weighted imaging (DWI) to visualise the structural connectivity within the brain. A commercial subcortical auto-segmentation tool was used to define the putamen as well as the amygdala, the STN and the cerebellum. Utilising the Julich Brain Atlas, nine cortical regions (Brodmann areas 44, 45, 3a/b, 4a/p, pre-SMA, SMA, and insula) were semi-automatically segmented. Structural connectomes were analysed through tractography, allowing for the parcellation of the putamen into four segments in relation to the anterior commissure. Two trajectories, occipital and frontal, were tested for segment coverage using stepwise injection of the therapeutic agent. A genetic algorithm was employed to simulate these injections and to compare the coverage of the target region.Tractography revealed a significant projection of motor areas to the superior posterior segment of the putamen, suggesting this region as more specific target for treating motor symptoms in PD via CED. Non-motor connections were most common in the inferior posterior segment for the amygdala and in the superior anterior segment for the insula. Both occipital and frontal trajectories were found to be equally feasible for targeting the putamen segments, with surgical feasibility varying by individual patient anatomy, and achieved comparable coverage, with no significant difference between them, highlighting the need for personalised surgical approaches.The application of DWI and tractography for the segmentation of the putamen by its cortical connections offers a pathway towards targeted gene therapy in PD. Identifying the posterior superior segment as the primary recipient of motor area projections and confirming the feasibility of using either the occipital or frontal trajectory underscores the flexibility in optimising therapeutic efficacy while conserving resources. This precise targeting could potentially allow for reduced dosages and more focused treatment, minimising exposure to non-motor segments of the putamen and associated risks.

OCT-kontrollierte Laserosteotomie für neurochirurgische Eingriffe: Ein neuer Ansatz für sicheren Knochenabtrag

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Stereotaxie

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FNCH 1Stereotaxie

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FNCH 1
Stereotaxie