Intraoperative Neuronavigation Research Articles

Evaluation of the Efficiency of Neuronavigation in Patients with Glioblastoma

Objective: To investigate the effect of neuronavigation use on mortality in patients with glioblastoma. Methods: For each of the 26 patients that underwent neuronavigation-assisted supratotal resection for glioblastoma between 2018 and 2020, one patient that underwent supratotal resection without navigation was selected. Results: Radiographic radicality was observed in 35% of the cases in the neuronavigation-assisted surgery group and 29% of those in the conventional surgery group. Absolute and relative residual tumor volumes were significantly lower in the neuronavigation-assisted surgery group. Radical tumor resection was associated with a very significant increase in survival. There was no significant difference in the survival rates between the patients that underwent surgery with and without neuronavigation. This was attributed to the small number of participants and supratotal resection being performed in all statistically determined patients The low median survival period of glioblastoma may have also contributed to this finding. Conclusions: Surgery plays an important role in the treatment of glioblastoma. A combination of techniques including intraoperative magnetic resonance imaging, neuronavigation, ultrasound, and fluorescence guidance allows for safe and maximum surgical resection, leading to better outcomes in terms of survival and postoperative functional recovery. However, despite maximal surgical resection and adjuvant chemotherapy-radiotherapy, most cases develop tumor recurrence within 10 months, which is considered to be due to established cancer stem cells. Therefore, there is an urgent need to develop more effective treatment strategies for glioblastoma.

Use of Mixed Reality in Neuro-Oncology: A Single Centre Experience

(1) Background: Intra-operative neuronavigation is currently an essential component to most neurosurgical operations. Recent progress in mixed reality (MR) technology has attempted to overcome the disadvantages of the neuronavigation systems. We present our experience using the HoloLens 2 in neuro-oncology for both intra- and extra-axial tumours. (2) Results: We describe our experience with three patients who underwent tumour resection. We evaluated surgeon experience, accuracy of superimposed 3D image in tumour localisation with standard neuronavigation both pre- and intra-operatively. Surgeon training and usage for HoloLens 2 was short and easy. The process of image overlay was relatively straightforward for the three cases. Registration in prone position with a conventional neuronavigation system is often difficult, which was easily overcome during use of HoloLens 2. (3) Conclusion: Although certain limitations were identified, the authors feel that this system is a feasible alternative device for intra-operative visualization of neurosurgical pathology. Further studies are being planned to assess its accuracy and suitability across various surgical disciplines.

Robotics and computer-assisted procedures in cranial neurosurgery

The medical technical innovations over the last decade have made operations in the highly sensitive regions of the brain much safer. Presentation of how far computer assistance and robotics have become incorporated into clinical neurosurgery. Evaluation of the scientific literature and analysis of the certification status of the corresponding medical devices. The rapid development of computer technology and the switch to digital imaging has led to the widespread introduction of neurosurgical planning software and intraoperative neuronavigation. In the field of robotics, the penetration into clinical neurosurgery is currently still largely limited to the automatic setting of trajectories. The digitalization of imaging has fundamentally transformed neurosurgery. In the field of cranial neurosurgery, computer-assisted procedures can now be distinguished from noncomputer-assisted procedures only in ahandful of cases. In the coming years important innovations for the clinical implementation can be expected in the field of robotics.

Combined Transoral Exoscope and OARM-Assisted Approach for Craniovertebral Junction Surgery. New Trends in an Old-Fashioned Approach.

The introduction of recent innovations in the field of intraoperative imaging and neuronavigation, such as the O-arm StealthStation, allows for obtaining crucial intraoperative data by performing safer and controlled surgical procedures. As part of the improvement of surgical visual magnification and wide expansion of surgical corridors, the 3D 4 K exoscope (EX) has nowadays become an interesting and useful tool. The transoral approach (TOA) is the historical gold-standard direct microsurgical route to ventral craniovertebral junction (CVJ). We herein report our experience, consisting of ten cases via TOA concerning the simultaneous application of an O-arm with a StealthStation navigation system (Medtronic, Memphis, TN) and an imaging system, along with the 3D 4 K exoscopes in the TOA, for the treatment of CVJ pathologies. No intraoperative neurophysiological changes or postoperative infections occurred, but neurological improvement was evident in all the patients. A complete decompression and a stable instrumentation and fusion of the CVJ were accomplished in all cases at the maximum follow-up time. With EX, the role of the surgeon becomes self-sufficient with better individual surgical freedom compared to endoscopic surgery and excellent 3D vision and magnification. O-arms offer absolutely reliable intraoperative support for more-effective CVJ decompression. Nevertheless, with O-arm-assisted neuronavigation, it can be difficult to navigate C1 lateral masses and C2 isthmi, and converting 3D into 2D real-time navigation can be quite complicated. Finally, the combination of an EX with an O-arm appears more time-consuming compared to the old-fashion one.

Deep motor cortex cavernoma resection supported by navigational intraoperative monitoring

Introduction: Cavernomas are benign hamartomas of cerebral and spinal vessels, accounting for less than 1% of all arteriovenous malformations. In general, surgical resection is the treatment of choice for enlarging cavernomas or those associated with medically refractory seizures. Herein, we report a case of an enlarged deep precentral gyrus cavernoma, with a discussion of the surgical approach and the impact of intra-operative neurophysiological monitoring on the preservation of motor function. Case description: A 30-year-old male was referred to our hospital due to 2-month history of focal seizures. Initial magnetic resonance imaging revealed right precentral cavernoma with minimal right parietal subarachnoid haemorrhage. Revealed the location of the cavernoma deep in the right primary motor cortex. Surgery was performed, trans-sulcal dissection was done with the aid of intraoperative ultrasonography neuro-navigation. The cortical motor map was localized by functional mapping with intra-operative neurophysiological monitoring, including somatosensory evoked potentials (SEP) and motor evoked potentials (MEP). Post-operatively, the left side weakness grade was 4/5, and the Glasgow coma scale was 15. Postoperative imaging confirmed successful resection of the cavernoma and associated hemosiderin ring with no SAH. Conclusion: The use of preoperative MRI and intraoperative ultrasonography supplemented by neurophysiological monitoring utilizing SEP, MEP, and cortical mapping is essential for the safe resection of paracentral cavernomas.

Bayesian Inference for Brain Activity from Functional Magnetic Resonance Imaging Collected at Two Spatial Resolutions.

Neuroradiologists and neurosurgeons increasingly opt to use functional magnetic resonance imaging (fMRI) to map functionally relevant brain regions for noninvasive presurgical planning and intraoperative neuronavigation. This application requires a high degree of spatial accuracy, but the fMRI signal-to-noise ratio (SNR) decreases as spatial resolution increases. In practice, fMRI scans can be collected at multiple spatial resolutions, and it is of interest to make more accurate inference on brain activity by combining data with different resolutions. To this end, we develop a new Bayesian model to leverage both better anatomical precision in high resolution fMRI and higher SNR in standard resolution fMRI. We assign a Gaussian process prior to the mean intensity function and develop an efficient, scalable posterior computation algorithm to integrate both sources of data. We draw posterior samples using an algorithm analogous to Riemann manifold Hamiltonian Monte Carlo in an expanded parameter space. We illustrate our method in analysis of presurgical fMRI data, and show in simulation that it infers the mean intensity more accurately than alternatives that use either the high or standard resolution fMRI data alone.

FUTURE-GB: functional and ultrasound-guided resection of glioblastoma – a two-stage randomised control trial

IntroductionSurgery remains the mainstay for treatment of primary glioblastoma, followed by radiotherapy and chemotherapy. Current standard of care during surgery involves the intraoperative use of image-guidance and 5-aminolevulinic acid (5-ALA)....

Surgical treatment of tumors of the supplementary motor area

Background. The supplementary motor area is a part of the medial frontal cortex, that is located just anterior to the primary motor cortex entirely within the interhemispheric fissure. This area belongs traditionally to the secondary motor cortex and perhaps it is the least studied motor region of the brain. While functions and symptoms of a damage to the primary motor and the premotor cortex areas have been well known and described for a long time, study of the supplementary motor area has been limited to fundamental neuroimaging and electrophysiological researches, and a practical side of the issue and clinical significance of this region remained outside the interest of researchers.Aim. To present the anatomical and functional features of the supplementary motor area, the clinical symptoms of its lesion, to analyze all the data available today and aspects of surgical treatment of tumors in this region.Materials and methods. A search in scientific databases (PubMed, etc.) led to the selection and analysis of sixty-two literary sources. The review is mainly devoted to the aspects and risk factors of surgical treatment of pathologies localized in this region.Results. According to its anatomical and functional characteristics, the supplementary motor area is a heterogeneous region - it has two separate subregions in it. In addition to the motor function of the supplementary motor area, its role has also been reliably established in the implementation of working memory processes, language, perceptual, cognitive and other functions. Such a number of functions performed by the supplementary motor area is associated with numerous neural connections of this area. For example, the frontal aslant tract has been described recently, and it connects medial part of the superior frontal gyrus with the pars opercularis of the inferior frontal gyrus. This tract, apparently, is associated with the implementation of language function in the dominant hemisphere and function of working memory in the non-dominant hemisphere.When the supplementary motor area is affected, various neurological motor and speech symptoms can occur, in particular, the supplementary motor area syndrome, which is characterized by the development of akinetic mutism in patients and, in most cases, is completely reversible within a few days or months. Among all pathologies in this area, tumors are most common, especially gliomas, which can also manifest themselves with various clinical symptoms both in the preoperative and postoperative periods.Conclusion. Critically important preoperative planning, informing the patient about the spatio-temporal picture of the predicted postoperative clinical disorders and the timing of rehabilitation are critically important. It is recommended to use methods of intraoperative neuronavigation, as well as intraoperative neurophysiological monitoring. It is necessary to further study the supplementary motor area and the peculiarities of its surgery in order to standardize approaches to the treatment of pathologies.

The Current State of Visualization Techniques in Endoscopic Skull Base Surgery.

Skull base surgery has undergone significant progress following key technological developments. From early candle-lit devices to the modern endoscope, refinements in visualization techniques have made endoscopic skull base surgery (ESBS) a standard practice for treating a variety of conditions. The endoscope has also been integrated with other technologies to enhance visualization, including fluorescence agents, intraoperative neuronavigation with augmented reality, and the exoscope. Endoscopic approaches have allowed neurosurgeons to reevaluate skull base neuroanatomy from new perspectives. These advances now serve as the foundation for future developments in ESBS. In this narrative review, we discuss the history and development of ESBS, current visualization techniques, and future innovations.

Karawun: a software package for assisting evaluation of advances in multimodal imaging for neurosurgical planning and intraoperative neuronavigation

PurposeThe neuroimaging research community—which includes a broad range of scientific, medical, statistical, and engineering disciplines—has developed many tools to advance our knowledge of brain structure, function, development, aging, and disease. Past research efforts have clearly shaped clinical practice. However, translation of new methodologies into clinical practice is challenging. Anything that can reduce these barriers has the potential to improve the rate at which research outcomes can contribute to clinical practice.In this article, we introduce Karawun, a file format conversion tool, that has become a key part of our work in translating advances in diffusion imaging acquisition and analysis into neurosurgical practice at our institution.MethodsKarawun links analysis workflows created using open-source neuroimaging software, to Brainlab (Brainlab AG, Munich, Germany), a commercially available surgical planning and navigation suite. Karawun achieves this using DICOM standards supporting representation of 3D structures, including tractography streamlines, and thus offers far more than traditional screenshot or color overlay approaches.ResultsWe show that neurosurgical planning data, created from multimodal imaging data using analysis methods implemented in open-source research software, can be imported into Brainlab. The datasets can be manipulated as if they were created by Brainlab, including 3D visualizations of white matter tracts and other objects.ConclusionClinicians can explore and interact with the results of research neuroimaging pipelines using familiar tools within their standard clinical workflow, understand the impact of the new methods on their practice and provide feedback to methods developers. This capability has been important to the translation of advanced analysis techniques into practice at our institution.

Pre- and intraoperative thoracic spine localization techniques: a systematic review.

In the era of modern medicine with an armamentarium full of state-of-the art technologies at our disposal, the incidence of wrong-level spinal surgery remains problematic. In particular, the thoracic spine presents a challenge for accurate localization due partly to body habitus, anatomical variations, and radiographic artifact from the ribs and scapula. The present review aims to assess and describe thoracic spine localization techniques. The authors performed a literature search using the PubMed database from 1990 to 2020, compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A total of 27 articles were included in this qualitative review. A number of pre- and intraoperative strategies have been devised and employed to facilitate correct-level localization. Some of the more well-described approaches include fiducial metallic markers (screw or gold), metallic coils, polymethylmethacrylate, methylene blue, marking wire, use of intraoperative neuronavigation, intraoperative localization techniques (including using a needle, temperature probe, fluoroscopy, MRI, and ultrasonography), and skin marking. While a number of techniques exist to accurately localize lesions in the thoracic spine, each has its advantages and disadvantages. Ultimately, the localization technique deployed by the spine surgeon will be patient-specific but often based on surgeon preference.

Single-Stage Posterior Transpedicular Corpectomy and 360-Degree Reconstruction for Thoracic and Lumbar Burst Fractures: Technical Nuances and Outcomes.

We evaluate the feasibility of a single-stage posterior corpectomy and circumferential arthrodesis with the aid of spinal navigation for the treatment of traumatic thoracolumbar burst fractures. This was a single-center, retrospective study. Demographics, clinical, and radiologic data of 19 patients who underwent surgery at our institution for thoracolumbar burst fractures between 2016 and 2019 were collected. All patients enrolled in the present study underwent surgery by means of posterior fixation and transpedicular corpectomy with the aid of an intraoperative image-guided neuronavigation system. Postoperative correction of the vertebral height ratio was achieved in all cases, with an average increase of 23.6% (p = 0.0005). No statistical differences (p = 0.9) were found comparing 1- and 3-month postoperative CT scans, in relation to vertebral height ratio. A statistically significant difference was found between the pre- and postoperative kyphotic angles for the thoracolumbar and lumbar segments (p = 0.0018 and 0.005, respectively), but no difference was found between kyphotic angles at the 3-month follow-up. A unilateral approach was performed on 15 patients (79%), while 4 cases (21%) required a bilateral laminectomy. We did not observe any significant intraoperative complication. Single-stage posterior corpectomy and fixation is a safe and effective approach for thoracic and lumbar burst fractures. It provides excellent 360-degree reconstruction in a single surgical stage with satisfactory results in terms of kyphosis reduction, biomechanical stability, and reduced invasiveness. Spinal navigation represents a fundamental tool to overcome some anatomical limits of the presented technique.

Multimodal Intraoperative Image-Driven Surgery for Skull Base Chordomas and Chondrosarcomas.

Simple SummaryAchieving gross total resection during the first surgical intervention is particularly important for chondrosarcomas and chordomas, as recurrences are frequently impossible to resect due to post-surgical and post-radiation scarring and vascular fragility. Despite overall survival and progression-free survival being strongly dictated by gross total resection, it is reportedly achieved in less than 70% of patients. While the individual utility of several imaging modalities such as intraoperative CT, MRI, ultrasound, endoscopy, fluoroscopy and neuronavigation has already been demonstrated in previous literature; our case series highlights the importance and methodology of their simultaneous, real-time integration in the Advanced Multimodality Image-Guided Operating (AMIGO) suite at our institution to maximize of resection and mitigate complications.Given the difficulty and importance of achieving maximal resection in chordomas and chondrosarcomas, all available tools offered by modern neurosurgery are to be deployed for planning and resection of these complex lesions. As demonstrated by the review of our series of skull base chordoma and chondrosarcoma resections in the Advanced Multimodality Image-Guided Operating (AMIGO) suite, as well as by the recently published literature, we describe the use of advanced multimodality intraoperative imaging and neuronavigation as pivotal to successful radical resection of these skull base lesions while preventing and managing eventual complications.

Incorporating Uncertainty Into Path Planning for Minimally Invasive Robotic Neurosurgery

New robotics devices can provide minimally invasive access to deep lesions in the brain through small openings in the skull, which can reduce infection risk and improve recovery times when compared to larger craniotomies. Several groups have introduced semi and fully automatic path planning tools to optimize lesion access while avoiding damage to critical structures along the path. These tools utilize preoperative imaging and intraoperative neuronavigation to plan and execute lesion access. However, several factors can introduce uncertainty into path planning, including segmentation, patient-to-image registration, brain shift during surgery, and mechanical uncertainty in the robotic device during path following. Most systems handle uncertainty by adding a ‘safety margin’ (typically 2–3 mm) around structures to be avoided or around the path. However, safety margins are somewhat arbitrary. We propose using more rigorous models of uncertainty during path planning. We explore two sources of uncertainty in path planning, namely segmentation uncertainty and uncertainty due to brain shift, propose a method for computing brain shift uncertainty, show how to combine these uncertainties into a single risk volume, and provide clinical motivation by presenting our approach in the context of a path planning system for robotic neurosurgery designed for treating mesial temporal lobe epilepsy.

CT-Based Intraoperative Navigation for Quick Identification of the Stylomastoid Foramen During Hypoglossal-Facial Nerve Anastomosis.

To present the ability of standard intraoperative neuronavigation to reliably identify the stylomastoid foramen, thus providing a quick and effective recognition of the facial nerve at its exit from the skull base. We describe the technical nuances of this procedure by presenting two surgical cases who underwent hypoglossal-facial nerve anastomosis for complete facial nerve palsy occurring post removal of a giant vestibular schwannoma 6 months earlier. CT-based neuronavigation allowed a quick and reliable identification of the stylomastoid foramen and of the facial nerve at its exit from the skull. The entire procedure lasted for 3 hours. Three months after the anastomosis, the first signs of facial muscle reinnervation were visible. The use of neuronavigation during hypoglossal-facial nerve anastomosis is a simple and cost-effective strategy to decrease operative duration and increase surgical effectiveness.

TMOD-17. A NOVEL GLIOBLASTOMA INVASION MODEL USING HUMAN BRAIN SLICE CULTURES

Abstract OBJECTIVE Glioblastoma (GBM) is among the most common of malignant brain tumours, with a median post-surgical survival of less than one year. Over the past several decades, therapies that appeared promising in mice models have failed during clinical trials due to the differences encountered during translation of research from model organisms to humans. To partially mitigate these difficulties in translation, we present a human cortical organotypic culture based GBM model, which allows us to manipulate individual components of the tumour environment in order to investigate the influence of different cell types in the immunosuppressive tumour microenvironment. METHODS Human neocortical tissue (at least 2 cm away from the tumour core) or entry cortex from epilepsy surgery guided by intraoperative neuro navigation, was cultured for up to 14 days post resection using an optimized medium. The cultured tissue was further injected with patient derived human GBM cells to create an ex vivo human model of glioblastoma model. The role of astrocytes in the tumour microenvironment was studied using microglia loss of function model. RESULTS Our established human neo-cortical slice model can recapitulate an in-vivo characteristics of glioblastoma from functional and imaging aspect. Our data corroborate differences between astrocytes in human and murine models in different reactive states, shows that the glioblastoma microenvironment can be difficult to be accurately modelled using murine models. Results from our human microglia depletion model, provided ample evidence that complex interaction of astrocytes and microglia cells, promotes an immunosuppressive environment in Glioblastoma by releasing high concentration of IL10 and TGFbeta (p< 0.001). CONCLUSION Our model therefore has potential applications to the fields of neuroscience, neuro-oncology, and pharmacotherapy.

Virtual reality-based 3-dimensional localization of stereotactic EEG (SEEG) depth electrodes and related brain anatomy in pediatric epilepsy surgery.

The increasing use of stereoelectroencephalography (SEEG) in the USA and the need for three-dimensional (3D) appreciation of complex spatial relationships between implanted stereotactic EEG depth electrodes and surrounding brain and cerebral vasculature are a challenge to clinicians who are used to two-dimensional (2D) appreciation of cortical anatomy having been traditionally trained on 2D radiologic imaging. Virtual reality and its 3D renderings have grown increasingly common in the multifaceted practice of neurosurgery. However, there exists a paucity in the literature regarding this emerging technology in its utilization of epilepsy surgery. An IRB-approved, single-center retrospective study identifying all SEEG pediatric patients in which virtual reality was applied was observed. Of the 46 patients identified who underwent an SEEG procedure, 43.5% (20/46) had a 3D rendering (3DR) of their SEEG depth electrodes. All 3DRs were used during patient-family education and discussion among the Epilepsy multidisciplinary team meetings, while 35% (7/20) were used during neuronavigation in surgery. Three successful representative cases of its application were presented. Our institution's experience regarding virtual reality in the 3D representation of SEEG depth electrodes and the application to pre-surgical planning, patient-family education, multidisciplinary communication, and intraoperative neuronavigation demonstrate its applicability in comprehensive epilepsy patient care.

P14.88 Management of primary CNS lymphomas. Experience of 32 cases

Abstract BACKGROUND Lymphomas (primary and secondary) are rare tumors of the central nervous system. They can involve both the supratentorial areas and the posterior cranial fossa. Modern management of patients with suspected CNS lymphoma should include a stereotactic or navigation-guided biopsy and subsequently carrying out chemotherapy and, in rare cases, radiosurgery. MATERIAL AND METHODS We analyzed our experience of the diagnosis and treatment of PCNSL. Our work included 32 patients with PCNSL. The study did not include patients with suspected CNS lymphoma, according to MRI data, in whom the diagnosis was not confirmed after biopsy. RESULTS Thirty patients underwent biopsy (20 - navigation guided, 1 - open, 9 - “burr hole”) with preliminary intraoperative histological verification. Gross total resection was performed in 2 cases since, according to preoperative MRI data, it was assumed that the patient had glial tumors. Postoperative histological examination confirmed the diagnosis of CNS lymphoma in all cases. Subsequently, after detailed histological and immunohistochemical studies, 30 patients underwent intra-arterial chemotherapy or high-dose chemotherapy according to NCCN protocols. Palliative treatment was recommended in 2 cases due to acute deterioration of patients. In our work, we would like to present a diagnostic algorithm and treatment regimens used in the management of our patients. CONCLUSION In the treatment of CNS lymphomas, careful histological verification is required, which is possible if several key points are performed - discontinuation of dexamethasone at least 24 hours before the biopsy, MRI for intraoperative neuronavigation after discontinuation of dexamethasone, intraoperative preliminary histological verification. In our opinion, complete removal of the tumor is possible if there are no risks of developing a persistent neurological deficit. Various methods of opening the blood-brain barrier are currently used, which can significantly reduce the effective dosage of drugs and, accordingly, the side effects. Further research is needed to determine the dependence of the prognosis of the disease on the type of surgery (biopsy or resection).

Computer-Aided Three-Dimensional Virtual Surgical Planning in Complex Skull Base Reconstruction for Sphenoid Wing Dysplasia in Neurofibromatosis Type 1.

Unilateral sphenoid dysplasia is a rare but distinctive manifestation of neurofibromatosis type 1, causing pulsatile exophthalmos, decreased vision, and facial deformity. Surgical intervention is required to prevent visual deterioration. However, the reconstruction of a complex cranial base defect while fulfilling cosmetic needs is challenging. The asymmetric anatomy impedes identification and preservation of vital structures, and the use of bone grafts is often unsustainable due to resorption. Here we demonstrate a multimodal technique combining mirror-image-based virtual surgical planning, stereolithography, and neuronavigation to achieve skull base reconstruction and restore facial symmetry in an neurofibromatosis type 1 patient with sphenoid dysplasia. Preoperative surgical planning involved mirror-image simulation based on the unaffected contralateral counterpart and a stereolithographic skull-base model fabricated to design a patient-specific titanium mesh. Surgical reconstruction via the transcranial approach under intraoperative neuronavigation was performed. Immediate resolution of pulsatile proptosis was observed postoperatively. With the help of virtual surgical planning, stereolithography, and neuronavigation, precise and sustainable reconstruction with patient-specific implants can be tailored for a complex skull base defect.

Augmented reality head-mounted display-based incision planning in cranial neurosurgery: a prospective pilot study.

Monitor and wand-based neuronavigation stations (MWBNSs) for frameless intraoperative neuronavigation are routinely used in cranial neurosurgery. However, they are temporally and spatially cumbersome; the OR must be arranged around the MWBNS, at least one hand must be used to manipulate the MWBNS wand (interrupting a bimanual surgical technique), and the surgical workflow is interrupted as the surgeon stops to "check the navigation" on a remote monitor. Thus, there is need for continuous, real-time, hands-free, neuronavigation solutions. Augmented reality (AR) is poised to streamline these issues. The authors present the first reported prospective pilot study investigating the feasibility of using the OpenSight application with an AR head-mounted display to map out the borders of tumors in patients undergoing elective craniotomy for tumor resection, and to compare the degree of correspondence with MWBNS tracing. Eleven consecutive patients undergoing elective craniotomy for brain tumor resection were prospectively identified and underwent circumferential tumor border tracing at the time of incision planning by a surgeon wearing HoloLens AR glasses running the commercially available OpenSight application registered to the patient and preoperative MRI. Then, the same patient underwent circumferential tumor border tracing using the StealthStation S8 MWBNS. Postoperatively, both tumor border tracings were compared by two blinded board-certified neurosurgeons and rated as having an excellent, adequate, or poor correspondence degree based on a subjective sense of the overlap. Objective overlap area measurements were also determined. Eleven patients undergoing craniotomy were included in the study. Five patient procedures were rated as having an excellent correspondence degree, 5 had an adequate correspondence degree, and 1 had poor correspondence. Both raters agreed on the rating in all cases. AR tracing was possible in all cases. In this small pilot study, the authors found that AR was implementable in the workflow of a neurosurgery OR, and was a feasible method of preoperative tumor border identification for incision planning. Future studies are needed to identify strategies to improve and optimize AR accuracy.