Sektionstage Herbst 2023 der Deutschen Gesellschaft für Neurochirurgie

PD Dr. med.

Prof. Dr. med.

Dr. med.

KD Dr. med.

The tailored, patient-adapted, transnasal endoscopic approach to the skull-base

Endoskopie in der Schädelbasischirurgie

Personalisierte Medizin & Metastasen

Abstract-Text Introduction: The conventional microsurgical technic has been the gold standard in the transnasal surgery of pituitary adenomas and central skull base tumors for many years. Nonetheless, over the past 2 decades, a slow shift towards purely endoscopic techniques has been observed (Májovský 2022). The endoscopic techniques not only offer a safe approach with better surgical and oncological outcomes (Karppinen 2015, Razak 2013, Castaño-Leon 2020) but with the proper interdisciplinary work the postoperative rhinological quality of life can be minimized or even improved (Graham 2009, Kahilogullari 2013, Eördögh 2017). Moreover, because of the avoidance of the speculum, the use of the endoscope comes with a better range of movement, allowing the surgeon to expand the approach widely in all directions. Methods and results: In our center, all endoscopic approaches are performed interdisciplinary in a 4-hand technique. The surgical plan is always considered depending on individual tumor location and extension, as well as, the anatomical nasal conditions of each patient. The transnasal endoscopic technique not only allows to reach the sellar and parasellar space but also to control inferiorly through the transclival approach, and superiorly over the transtuberculum/transplanum approach. In addition, with the lateral extension according to the transmaxillary/transpterigoyd/infratemporal approach, we are able to visualize the sinus cavernosus and petrous apex. If necessary, we tailor the approach from mono-nostril to bi-nostril or even combine the transnasal dissection with a transcranial exposure in one session. In this way, a combined transnasal-transcranial can be used in cases where the intracranial expansion of the tumor cannot be reached in a purely transnasal way. Conclusion: Over the past 14 years, our interdisciplinary rhino-neurosurgical team in Zürich has been developing a minimal-invasive tailored transnasal endoscopic approach. The main idea is to generate enough working space through the nose without compromising the olfactory mucosa and without the removal of nasal turbinates. The concept is to be as minimal-invasive as possible but to be able to expand the approach as much as necessary. The design of a structured, case-specific, surgical plan allows the surgical treatment of all anterior skull-base tumors, going from small midline tumors to large extensive ones (a.e. chordomas, sarcomas, and aesthesioneuroblastomas).

Abstractvortrag

PD Dr.

Prof.

IMAGINER – Improving accuracy with augmented reality navigation system during placement of external ventricular drains: A feasibility study

Wachoperation und Kognition

Abstract-Text Abstract: Background: Placement of a ventricular catheter (i.e. external ventricular drain, EVD) is a common and essential neurosurgical procedure. In addition, this procedure is one of the first procedures performed by young neurosurgeons. With or without surgical experience, placement of an EVD according to anatomical landmarks only can be difficult with the potential risk for inaccurate catheter placement. Repeated corrections always imply the risk of avoidable complications. Augmented reality (AR) could provide a useful guide and improve the accuracy of drain placement, especially in patients with acute pathology leading to displacement of anatomical structures. We therefore performed a feasibility study using AR in EVD placement procedures performed in a human cadaver model. Methods: 20 medical students performed the EVD placement procedure with a Cushing´s ventricular cannula on the right and on the left side. The cannula was placed according to landmarks on one and with the assistance of AR (Microsoft Hololens 2) on the other side. With AR a planned trajectory was displayed in the field of view which guides the placement of the cannula. Subsequently, the actual position of the cannula was assessed with the help of a CT with 1mm layer thickness. The bony structure as well as the left and right cannula positions were registered to the CT with the planned target point before the placement procedure. The software Cloudcompare was applied for the registration and the evaluation of accuracy. Results: EVD placement using AR was easily performed by all medical students. The predefined target point (inside the lateral ventricle) was stuck with both techniques. However, it could be shown that the scattering radius of the target point reached with AR (12mm) could be reduced by more than 54% compared to the puncture without AR (26mm) and this represents a doubling of the puncture accuracy. Conclusion: This feasibility study specifically showed that the integration and use of augmented reality helps to achieve more than double the accuracy in the placement of ventricular catheters. Due to the easy availability of these new tools and the intuitive handling, we see great potential in AR to improve the accuracy.

Mixed reality for spine surgery – A step into the future – A human cadaveric accuracy study

Abstract-Text Objective Current application of mixed reality (MR) as a navigation aid in the field of spinal navigation point to the potential of this technology in spinal surgery. Crucial factors for acceptance include intuitive workflow system stability, reliability, and accuracy of the method. We therefore aimed to investigate the accuracy in visualization of anatomical structures using MR on the example of pedicles of the thoracic spine in a human cadaveric study. Potential difficulties and limitations are discussed. Methods. Computed tomography (CT) scans of a human cadaveric spinal column specimen was performed. After segementation, and import into the advanced Holoens 2 software, the vertebrae were exposed. The vertebral arches were preserved on one side for a landmark-based surface registration, while pedicles were exposed on the other side in order to measure and evaluate deviation of the overlay holographs to the exact anatomical structure. Accuracy was measured and statistically evaluated. Results. In this work it could be demonstrated that the overlay of the virtual 3D model pedicles with the real anatomical structures with anatomical landmark registration is with the mean value of 2.1mm (max. 3.8mm, min. 1.2mm) within an acceptable surgical accuracy. The highest accuracy could be registered at the medial and lateral pedicle wall and the measurement results were best in the region of the middle thoracic spine. Conclusion. The accuracy analysis for MR, i.e. between virtual and real anatomical situation of the thoracic spine shows a very good agreement with focus on the pedicles. The work is thus a rare proof of the precision of segmentation to the potential surgical area. The results encourage to open up MR technology in its development and application for spinal navigation.

Student´s perspectives regarding needs and opportunities on mixed-reality education at German medical schools in neurosurgery

Freie Themen

Abstract-Text Objective: Despite mixed-reality being an emerging tool for tailored neurosurgical treatment and safety enhancement, the use of mixed-reality in the education of german medical students is not established in the field of neurosurgery. The present study aimed to investigate medical students" perspectives on mixed-reality in medical education of neurosurgical knowledge. Methods: Between July 3 rd , 2023 and August 30 th , 2023, an online survey was performed among German medical students through their student"s associations and the educational institutions they were affiliated with. The survey included 17 items related to mixed-reality in neurosurgery, with participants providing ratings on a 4-point Likert scale to indicate their level of agreement with the statements. Results: A total of 150 students from 27 medical faculties in Germany took part in the survey. A significant majority (87.3%) comprising 131 students expressed strong to intense interest in mixed-reality courses in neurosurgery and 108 (72%) reported an interest in incorporating mixed-reality into their curriculum. Furthermore, 94.7% agreed, that mixed-reality might enhance their understanding of operative neuroanatomy and 72.7% agreed with the idea that the teaching via mixed-reality methods might increase the probability to use mixed- reality in their future career. The majority (116/150; 77.3%) reported that the preferred optimum timepoint for teaching with mixed-reality might be within the first three years of medical school. Students studying within the first two years particularly preferred to start mixed-reality courses in the first two years of medical school compared to students within their third to sixth year of medical school (71.9% vs. 41.5%, p = 0.003). Residents and attending specialists are believed to be the appropriate teachers by 118 students (78.7%). Conclusions: German medical students exhibit significant interest and willingness to engage in mixed-reality in neurosurgery. Evidently, there is a high demand for medical schools to provide mixed-reality courses. Students seem to prefer the courses as early as possible in their medical school to transfer the preclinical neuroanatomical knowledge into operative neurosurgical anatomy using this promising technique.

ioMRI in a state-of-the-art neuro-oncological setup – Impact on glioblastoma resection and clinical outcomes

Kognition & Konnektom

Abstract-Text Objective Intraoperative magnetic resonance imaging (ioMRI) is applied to improve the extent of resection in patients suffering from brain lesions, especially primary brain tumors. While the safety and feasibility have been proven in several studies and are generally acknowledged, the role of ioMRI in a modern neurooncological setting has not been sufficiently investigated so far. This study aimed to evaluate the effect of ioMRI on the extent of resection, neurological outcome, and progression-free survival (PFS) in GBM patients in a modern high-volume center. Methods Patients undergoing ioMRI for the resection of supratentorial GBM were prospectively included between March 2018 and June 2020. ioMRI was performed after complete macroscopic tumor resection in all cases. Volumetric analysis was performed to assess the extent of resection (EOR), with gross total resection (GTR) being defined as EOR ³95%. The progression-free survival (PFS) was analyzed using univariate and multivariate Cox proportional regression analysis. Results In total, 172 patients were included in this study. The mean EOR increased from 93·9% on ioMRI to 98·3% (p&lt;0·0001) on postoperative MRI, with the GTR rate increasing from 78·5% to 93·0% (p=0·0002). The residual tumor volume decreased from 1·3 ± 4·2 cm3 to 0·6 ± 2·5 cm3 (p=0·0037). Recurrent GBM (odds ratio [OR] =3·047, 95% confidence interval [CI] 1·165–7·974, p=0·023) and tumor volume less than 15 cm3 (OR=3·031, 95% CI 1·062–8·651, p=0·038) were identified as independent risk factors leading to STR. Additional tumor resection after ioMRI achieved equally long PFS, compared to patients with complete tumor resection before ioMRI (HR=0·898, 95%CI 0·543–1·483, p=0·67). Furthermore, regarding neurological outcomes three months postoperatively, no significant differences in surgery-related motor deficits (p=0·063) and language deficits (p=0·12) were found. Conclusion ioMRI serves as a valuable tool in a modern neurooncological setting. It severely decreases residual tumor volume and helps to achieve comparable clinical outcomes in terms of surgery-related neurological deficits and PFS, even in cases where an unexpected tumor residual is found on ioMRI after initial resection. Disclosure: This research has already been published: Zhang W, Ille S, Schwendner M, Wiestler B, Meyer B, Krieg SM. The Impact of ioMRI on Glioblastoma Resection and Clinical Outcomes in a State-of-the-Art Neuro-Oncological Setup. Cancers (Basel). 2023;15(14).

Univ.-Prof. Dr. med.

Combined use of 3D printing and mixed reality technology for neurosurgical training: Getting ready for brain surgery

Abstract-Text Objective Learning surgical skills is an essential part of neurosurgical training. Ideally, these skills are acquired to a sufficient extent in an ex vivo setting. We previously described an in vitro brain tumor model, consisting of a cadaveric animal brain injected with fluorescent agar-agar, for acquiring a wide range of basic neuro-oncological skills. This model focuses on haptic skills such as safe tissue ablation technique and the training of fluorescence-based resection. As important didactical technologies such as mixed reality and 3D printing become more readily available, we developed a readily available training model that integrates the haptic aspects into a mixed reality setup. Methods The anatomical structures of a brain tumor patient were segmented from medical imaging data to create a digital twin of the case. Bony structures were 3D printed and combined with the in vitro brain tumor model. The segmented structures were visualized in mixed reality headsets and the congruence of the printed and the virtual objects allowed them to be spatially superimposed. In this way, users of the system were able to train the entire treatment process from surgery planning to instrument preparation and execution of the surgery. Results Mixed reality visualization in the joint model facilitated model (patient) positioning as well as the craniotomy and the extent of resection planning respecting case-dependent specifications. The advanced physical model allowed brain tumor surgery training including skin incision, craniotomy, dura opening, fluorescence-guided tumor resection and dura, bone, and skin closure. Conclusions Combining mixed reality visualization with the corresponding 3D printed physical hands-on model allowed advanced training of sequential brain tumor resection skills. 3D printing technology facilitates the production of a precise, reproducible, and world-wide accessible brain tumor surgery model. The described model for brain tumor resection advanced regarding important aspects of skills training for neurosurgical residents, e.g., locating the lesion, head position planning, skull trepanation, dura opening, tissue ablation techniques, fluorescence-guided resection and closure. Mixed reality enriches the model with important structures that are difficult to model (e.g., vessels, fibre tracts etc.) and advanced interaction concepts (e.g., craniotomy simulations). Finally, this concept demonstrates a bridging technology towards intraoperative application of mixed reality.

Seminarraum 4

Technik & Innovation

Endoskopie und Visualisierung

Sektion Technik & Innovation

Technik & Innovation
Endoskopie und Visualisierung

Appointment

Chairs

Programme

Technik & InnovationEndoskopie und Visualisierung

Appointment

Chairs

Programme

Technik & Innovation
Endoskopie und Visualisierung