During the last 15 years, neuronavigation has become an essential neurosurgical tool for pursuing minimal invasiveness and safety. One drawback of such devices is the fact, that the neurosurgeon has to look away from the surgical field onto a dedicated workstation screen. Additionally, the operator is required to transfer this information from the "virtual" environment of the navigation system to the real surgical field - whereas the real patient may be fixated and positioned differently compared to the visualization on the screen.

Mixed-reality may have the potential to support this, by merging data from the real environment with virtual information and vice-versa. In the context of surgical navigation, the main goal of mixed reality systems is to provide a real-time updated 3D virtual model of anatomical details, overlaid on the real surgical field. In this sense, the mixed reality is the process of enrichment of reality with additional virtual contents.

This clinical investigation aims at the collecting of clinical data about the mixed-reality supported planning, the registration accuracy and overall precision of the navigation system and the clinical outcome.

The CORTEXPLORER MED system is a platform that enables surgical navigation using radiological images of patients. The application software reads, formats and merges patient-specific multimodal images such as pre-surgical computed tomography (CT), magnetic resonance imaging (MRI, fMRI) as well as intraoperatively taken fluoroscopic scans. These digital representations of the patient are displayed on a computer screen from different anatomical perspectives (axial, sagittal, coronal, diagonal). Moreover, a 3D digital model can be computed based on the 2D imaging data. Before the operation, the surgeon can create, save, and simulate the course along one or more surgical trajectories. During surgery, the system tracks the position of specific surgical instruments in or on the patient's anatomy and continuously updates their position, which can be displayed on a computer screen or trough mixed reality glasses (Microsoft HoloLens).

Generally, this clinical investigation aims at the collecting of clinical data to indicate the difference between the planning of a neurosurgery without and with the mixed reality feature of CORTEXPLORER MED.

Additionally, clinical data is collected to indicate the difference between the planning of a surgery with the CORTEXPLORER MED and without the system (conventional approach for this indication).

The data from this pilot phase are used for the planning of a larger clinical investigation and for the overall clinical evaluation of the navigation system.

Inclusion Criteria:

• Patients of any gender in the age older or eqal 18 years
• Patients who be informed of the nature of the clinical investigation and provide written informed consent
• Patients with a cerebral aneurysm for which surgical clipping is indicated
• Patients with a cerebral aneurysm where clipping is not routinely supported by navigation
• Patients with current (not longer than 4 months) 3D image data of the brain

Exclusion Criteria:

• Patients for whom required imaging is not available
• Patients with ruptured cerebral aneurysm
• Detained patients
• Patients performing mandatory military service / community service
• Patients who refuse to participate in the clinical investigation
• Pregnant or nursing patients
• Patients who are not able to sign the consent form
• Patients who do not speak German
• Patients who are taking part in any other clinical investigations