Minimally invasive skull base surgery, once a niche, is now a cornerstone, driven by major technological advances and maturing anatomical understanding. Improvements in visualization, particularly the widespread availability of highdefinition and 4K systems, combined with classic cadaveric dissections, have raised the bar of minimally invasive skull base surgery. However, the clinical exposure required to build proficiency remains limited. Many of these pathologies are uncommon, and case volumes for complex extended skull base approaches may be sporadic even in high volume centers. While cadaveric dissection remains the gold standard for anatomical education and procedural rehearsal, access to cadavers is constrained by availability, cost, and logistics. These realities create a persistent training gap, particularly for residents and fellows who need repeated, deliberate practice to assimilate corridor anatomy and operative choreography.
Augmented reality (AR) entered the neurosurgical arena in the late twentieth century. It has expanded across multiple neurosurgical avenues, including skull base, cerebrovascular, neuro-oncology, spine, epilepsy, and functional neurosurgery. In practical terms, augmented reality refers to a process in which the software ingests patient imaging data and reconstructs relevant anatomy, such as a tumor and adjacent critical structures, including cranial nerves and major blood vessels. These reconstructions can then be displayed as an overlay on the operative field, through the operating microscope, endoscopes, or dedicated AR eyeglasses. Unlike virtual reality (VR), which replaces the user’s real-world view with a fully simulated environment, augmented reality preserves the real patient and superimposes digital information on top of what the surgeon is seeing. This overlay can be particularly useful when normal tissue planes are distorted by factors such as scarring, adhesions, or tumor-related displacement, making anatomical boundaries less distinct. By projecting the preoperative imaging-derived anatomy onto the surgical view after exposure, augmented reality can help the surgeon maintain spatial orientation and anticipate the likely location of vessels and cranial nerves relative to the lesion. With skull base lesions, the target is often deep, and normal landmarks may be obscured by overlying brain, narrow corridors, and tumor-related distortion. In that setting, this anatomy can be initially disorienting. This is particularly evident during intratumoral work, where the operative view is limited and the usual reference landmarks are no longer within the operative frame. For example, in an endoscopic approach to an anterior skull base pathology, as dissection proceeds deeper within the lesion, the relationship to critical vascular structures such as the paraclival internal carotid artery can become difficult to judge, especially if the artery is displaced, splayed, or partially encased by bone or tumor. If the surgeon’s attention is too focused and spatial awareness is lost, complications may arise
Augmented reality can mitigate this problem by projecting a translucent, imaging-derived overlay onto the live surgical view. When aligned appropriately, the overlay helps the surgeon reestablish spatial awareness by indicating where key anatomical structures are relative to the current field of view. In deep corridors, this reorients the surgeon and allows them to focus on the task while remaining spatially aware. During the superficial stages, it can support predissection planning by clarifying the lesion’s depth and boundaries, thereby informing the intended trajectory and angle of approach. This utility is particularly relevant for middle fossa and posterior fossa skull base lesions. Taken together, these advantages suggest that augmented reality may indirectly improve operative efficiency by helping surgeons maintain orientation, confirm trajectories, and identify critical anatomy more rapidly. In turn, this has the potential to shorten operative time and, by reducing uncertainty and unintended deviation in deep corridors, may also lower the risk of complications. That said, broader adoption and more standardized evaluation are needed before these benefits can be quantified reliably and synthesized across studies.
Neurosurgery today is fundamentally different from what it was a century ago. Contemporary practice operates under heightened medicolegal scrutiny, rising patient expectations, and minimal tolerance for complications. In parallel, exposure to highly complex skull base pathology may be limited in many training environments, which can dilute experiential learning and widen the gap between the skills trainees must acquire and the opportunities available to acquire them. This reality supports the case for adjunct technology not as a luxury but as a practical tool to bridge training needs while maintaining the standard of care patients deserve. When residents and fellows incorporate augmented reality into their routine learning and operative workflows, it can reinforce anatomical orientation, sharpen three-dimensional corridor-based understanding, and promote safer intraoperative decision-making. If the infrastructure exists to overlay imaging-derived anatomy onto the operative field, augmented reality can also function as a “double-check” in moments of uncertainty, helping the surgeon confirm the proximity of ongoing dissection planes to critical neurovascular structures. When in doubt, a surgeon is unlikely to hesitate to use a readily available tool that enhances spatial awareness and situational confidence. Of course, augmented reality must be applied thoughtfully. Limitations such as brain shift can reduce overlay accuracy if the system relies solely on preoperative imaging. However, these constraints are increasingly addressable through multimodal integration, such as coupling augmented reality with real-time intraoperative ultrasound to dynamically update anatomy.
It is also important to distinguish between augmented reality and the emerging concept of mixed reality. Mixed reality extends beyond simple overlay by allowing the virtual content to be spatially anchored to the real world and interact with the user in an immersive, dynamic way, effectively behaving like a manipulable hologram that remains registered to the live scene the operator is viewing. In some training programs, 3D-printed skull base models have been paired with augmented reality software. Once the physical model is generated after being scanned or derived from digital segmentation, key structures such as cranial nerves and major vessels are displayed as overlays while trainees rehearse skull base approaches on the model. This creates a repeatable environment in which learners can practice approaches and maintain awareness of critical anatomy that is otherwise difficult to visualize consistently during early training.¹ A natural next step, contingent on appropriate consent and ethical oversight, is patient-specific rehearsal. Imaging-derived datasets can be used to generate 3D prints of actual skull base tumors, including their relationships to cranial nerves and vascular structures. Trainees can then practice tumor removal on these patient-specific 3D-printed models with augmented reality guidance to anticipate operative planes, corridor constraints, and points of risk. Such simulations will never fully replicate live surgery, for example there is no true bleeding and deep down mentally we are cognizant of this fact. However, these models can still improve spatial orientation and set more accurate expectations for intraoperative anatomy.
Looking forward, the most compelling opportunity may be the integration of 3D-printed patient-specific models with augmented or mixed reality to simulate intraoperative contingencies, not just “ideal” anatomy. For instance, one could envision a scenario in which the AR/mixed reality overlay reproduces an inadvertent internal carotid artery injury: the trainee encounters the event during a simulated tumor resection, applies a temporary clip, performs a repair maneuver on the model vessel (e.g., suturing a printed carotid analog), and then removes the temporary clip within a defined time window. Building structured, interactive crisis modules of this kind would meaningfully raise the ceiling of skull base training by rehearsing both routine corridor work and high-stakes complication management in a controlled laboratory setting.
More broadly, augmented reality should not be framed as a standalone technological milestone. In a training ecosystem, immersive virtual reality, cadaveric dissection, 3D-printed models, wet-lab simulation, and mixed reality are complementary modalities, each addressing different components of skill acquisition. The long-term goal is clear: augmented reality or mixed reality, paired with high-fidelity, patient-specific 3D-printed models, should closely resemble the operative experience so that trainees can rehearse not only the ideal approach but also the decision points, risk zones, and contingency planning that define safe skull base surgery. In parallel, objective assessment must be built into the curriculum. Standardized metrics such as approach completion, anatomical violations, operative efficiency, instrument discipline, and situational awareness can be used to aid faculty in evaluating the readiness of trainees to perform surgery in a reproducible manner. The practical payoff is a safer, more trustworthy transition
from the laboratory to the operating room: when a trainee demonstrates consistency and judgment in simulation, the attending neurosurgeon can confidently delegate discrete operative steps under supervision, rather than relying solely on subjective impressions or sporadic case exposure.
Reference
- Lee MH, Lee TK. Cadaver-Free Neurosurgical Simulation Using a 3-Dimensional Printer and Augmented Reality. Oper Neurosurg. 2022;23(1):46-52. doi:10.1227/ons.0000000000000184
