Use of Augmented Reality and 3D Simulation for Anterior Skull Base Approach

The use of advanced technology, simulation and visualization in neurosurgery has been an evolving field in the past 5 years. Navigation assisted neurosurgery and now simulation integrated neurosurgery, has shown to be a highly useful step in the preoperative phase.

The neurosurgical team prepared the patient for computer-assisted resection creating a 3D-simulated view of the patient’s anatomy. Standard volumetric sequence isotropic MRI and contrast CT sequences were obtained, loaded, and fused to one another using Brainlab’s curve and Surgical Theater’s SNAP technology. This was followed by segmentation of operative structures. Where MRI data can be used to extract information about soft tissue anatomical structures and pathology where CT and CTA data can help to define boney and vascular structures.

During preoperative planning we employed Brainlab Cranial Software for navigation and used the Smartbrush element to create objects of interest. The Smartbrush tool is a computer-assisted paintbrush that allows the user to outline the critical structures from the patient’s radiographic data. These objects are then uploaded into the navigation platform and used in a heads up display (HUD) configuration with an intraoperative microscope. Here, the objects of interest were overlaid onto the patient’s anatomy through the eyepieces in real time. Stereotactic navigation defines the coordinate frame for the microscope. The registration information may also be exported to a 3D simulation platform to help increase visualization and situational awareness during surgery.

In a few specific cases tumor located in the anterior skull base involved one or more of the following: optic nerves, optic chiasm, carotid artery, or basilar artery. Reviewing the simulation during the preoperative planning phase allowed for an enhanced ability to make decisions about surgical approach.

Case 1: A 54-year-old female presented with a tuberculum meningioma compressing the optic nerve. During the preoperative planning phase the team was able to visualize the transbrow approach to confirm simulated findings.

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Case 2: A 52-year-old female presented with a known tuberculum sella meningioma causing vision loss. Patient underwent a bicoronal incision, during the procedure critical structures (carotid artery, and branches of ACA, optic nerves) outlined by HUD were identified and helped to guide resection with the goal of preserving the left optic nerve which had been displaced and compressed by tumor. On the left side, the tumor had grown into the optic canal, between the internal carotid artery and the optic nerve.

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Case 3: A 57-year-old male with a large recurrent pituitary tumor compressing the optic nerve and surrounding carotid arteries. The case was approach in two parts: both cranial and endoscopic as determined by the extent of the tumor. Intraoperatively patient was positioned and transbrow incision was outlined for a minimal exposure that would allow for access to the area of tumor that was causing vision loss. HUD was utilized to confirm positioning would allow for appropriate approach to tumor/optic intersection.

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