Microsurgical clipping of middle cerebral artery aneurysms: preoperative planning using virtual reality to reduce procedure time.

OBJECTIVE: The authors sought to evaluate the impact of virtual reality (VR) applications for preoperative planning and rehearsal on the total procedure time of microsurgical clipping of middle cerebral artery (MCA) ruptured and unruptured aneurysms compared with standard surgical planning. METHODS: A retrospective review of 21 patients from 2016 to 2019 was conducted to determine the impact on the procedure time of MCA aneurysm clipping after implementing VR for preoperative planning and rehearsal. The control group consisted of patients whose procedures were planned with standard CTA and DSA scans (n = 11). The VR group consisted of patients whose procedures were planned with a patient-specific 360° VR (360VR) model (n = 10). The 360VR model was rendered using CTA and DSA data when available. Each patient was analyzed and scored with a case complexity (CC) 5-point grading scale accounting for aneurysm size, incorporation of M2 branches, and aspect ratio, with 1 being the least complex and 5 being the most complex. The mean procedure times were compared between the VR group and the control group, as were the mean CC score between the groups. Comorbidities and aneurysm conduction (ruptured vs unruptured) were also taken into consideration for the comparison. RESULTS: The mean CC scores for the control group and VR group were 2.45 ± 1.13 and 2.30 ± 0.48, respectively. CC was not significantly different between the two groups (p = 0.69). The mean procedure time was significantly lower for the VR group compared with the control group (247.80 minutes vs 328.27 minutes; p = 0.0115), particularly for the patients with a CC score of 2 (95% CI, p = 0.0064). A Charlson Comorbidity Index score was also calculated for each group, but no statistical significance was found (VR group, 2.8 vs control group, 1.8, p = 0.14). CONCLUSIONS: In this study, usage of 360VR models for planning the craniotomy and rehearsing with various clip sizes and configurations resulted in an 80-minute decrease in procedure time. These findings have suggested the potential of VR technology in improving surgical efficiency for aneurysm clipping procedures regardless of complexity, while making the procedure faster and safer.

Real-time navigation guidance with intraoperative CT imaging for pedicle screw placement using an augmented reality head-mounted display: a proof-of-concept study.

OBJECTIVE: Augmented reality (AR) has the potential to improve the accuracy and efficiency of instrumentation placement in spinal fusion surgery, increasing patient safety and outcomes, optimizing ergonomics in the surgical suite, and ultimately lowering procedural costs. The authors sought to describe the use of a commercial prototype Spine AR platform (SpineAR) that provides a commercial AR head-mounted display (ARHMD) user interface for navigation-guided spine surgery incorporating real-time navigation images from intraoperative imaging with a 3D-reconstructed model in the surgeon's field of view, and to assess screw placement accuracy via this method. METHODS: Pedicle screw placement accuracy was assessed and compared with literature-reported data of the freehand (FH) technique. Accuracy with SpineAR was also compared between participants of varying spine surgical experience. Eleven operators without prior experience with AR-assisted pedicle screw placement took part in the study: 5 attending neurosurgeons and 6 trainees (1 neurosurgical fellow, 1 senior orthopedic resident, 3 neurosurgical residents, and 1 medical student). Commercially available 3D-printed lumbar spine models were utilized as surrogates of human anatomy. Among the operators, a total of 192 screws were instrumented bilaterally from L2-5 using SpineAR in 24 lumbar spine models. All but one trainee also inserted 8 screws using the FH method. In addition to accuracy scoring using the Gertzbein-Robbins grading scale, axial trajectory was assessed, and user feedback on experience with SpineAR was collected. RESULTS: Based on the Gertzbein-Robbins grading scale, the overall screw placement accuracy using SpineAR among all users was 98.4% (192 screws). Accuracy for attendings and trainees was 99.1% (112 screws) and 97.5% (80 screws), respectively. Accuracy rates were higher compared with literature-reported lumbar screw placement accuracy using FH for attendings (99.1% vs 94.32%; p = 0.0212) and all users (98.4% vs 94.32%; p = 0.0099). The percentage of total inserted screws with a minimum of 5° medial angulation was 100%. No differences were observed between attendings and trainees or between the two methods. User feedback on SpineAR was generally positive. CONCLUSIONS: Screw placement was feasible and accurate using SpineAR, an ARHMD platform with real-time navigation guidance that provided a favorable surgeon-user experience.

Extended reality platform for minimally invasive endoscopic evacuation of deep-seated intracerebral hemorrhage: illustrative case.

BACKGROUND: Extended reality (XR) offers an interactive visualization platform that combines virtual reality (VR) for preoperative planning and augmented reality (AR) for intraoperative navigation overlay. OBSERVATIONS: XR was used for treating a case of spontaneous intracerebral hemorrhage (ICH) requiring neurosurgical intervention to decompress a hemorrhage in the subcortical area involving the thalamus that was starting to compress the midbrain. The selected surgical technique was an endoscopic aspiration combined with neurosurgical navigation. Because of the deep-seated location of this ICH, a patient-specific 360XR model rendered using Surgical Theater was used for preoperative planning and intraoperative navigation to allow for enhanced visualization and understanding of the pathology and surrounding anatomy. LESSONS: The XR platform enabled visualization of critical structures near the ICH by extracting and highlighting the white matter tracts from magnetic resonance imaging (MRI) with tractography, which improved preoperative planning beyond using state-of-the-art neuronavigation techniques alone. Once the trajectory was set, the model was integrated with the neuronavigation system, and the planned approach was referenced throughout the procedure to evacuate the clots without further injuring the brain. The patient tolerated the procedure well and was doing well 11 months after his spontaneous ICH.

Patient-specific virtual reality technology for complex neurosurgical cases: illustrative cases.

BACKGROUND: Virtual reality (VR) offers an interactive environment for visualizing the intimate three-dimensional (3D) relationship between a patient's pathology and surrounding anatomy. The authors present a model for using personalized VR technology, applied across the neurosurgical treatment continuum from the initial consultation to preoperative surgical planning, then to intraoperative navigation, and finally to postoperative visits, for various tumor and vascular pathologies. OBSERVATIONS: Five adult patients undergoing procedures for spinal cord cavernoma, clinoidal meningioma, anaplastic oligodendroglioma, giant aneurysm, and arteriovenous malformation were included. For each case, 360-degree VR (360°VR) environments developed using Surgical Theater were used for patient consultation, preoperative planning, and/or intraoperative 3D navigation. The custom 360°VR model was rendered from the patient's preoperative imaging. For two cases, the plan changed after reviewing the patient's 360°VR model from one based on conventional Digital Imaging and Communications in Medicine imaging. LESSONS: Live 360° visualization with Surgical Theater in conjunction with surgical navigation helped validate the decisions made intraoperatively. The 360°VR models provided visualization to better understand the lesion's 3D anatomy, as well as to plan and execute the safest patient-specific approach, rather than a less detailed, more standardized one. In all cases, preoperative planning using the patient's 360°VR model had a significant impact on the surgical approach.

De novo formation of large arteriovenous shunting and a vascular nidus mimicking an arteriovenous malformation within an anaplastic oligodendroglioma: treatment with embolization and resection.

The authors report the de novo occurrence and treatment of an arteriovenous lesion within an anaplastic oligodendroglioma in a patient with previously unremarkable brain imaging. Intracranial arteriovenous malformations (AVMs) are believed to be congenitally acquired lesions, and their association with brain neoplasms is extremely rare. Diagnostic imaging revealed a mass lesion with large arteriovenous shunts and a vascular nidus mimicking a true AVM. Histological and immunohistochemical testing showed an anaplastic oligodendroglioma mixed with an AVM. The clinical, radiological, and operative data are reviewed, as are the histopathological findings. To the authors' knowledge this is the first case of de novo occurrence of an arteriovenous lesion with large shunts and a vascular nidus within an anaplastic oligodendroglioma.

An Unusual Presentation of Creutzfeldt-Jakob Disease and an Example of How Hickam's Dictum and Ockham's Razor Can Both Be Right.

Patients can have more than one neurological problem, and sorting out acute from chronic disease can be challenging. The authors report a middle-aged patient who presented with ataxia, right hemiparesis, and abnormal nystagmus. Magnetic resonance imaging (MRI) showed a Chiari and an arachnoid cyst with brainstem compression that appeared to explain his abnormal examination. Shortly after admission, he was noted to have intermittent abnormal behavior and confusion. History from family revealed significant acute and chronic psychiatric problems that appeared to explain his abnormal mental status; this delayed the diagnosis of intermittent complex partial seizures. The multitude of various symptoms resulted in a delay of the final diagnosis of Creutzfeldt-Jakob disease (CJD), which in retrospect explained the entire new physical examination, seizures, and mental status changes.

Endoscopic removal of cisternal neurocysticercal cysts. Technical note.

The authors report the use of neuroendoscopy for the treatment of cisternal neurocysticercosis. The utilization of the endoscope is meant to provide a safe and minimally invasive procedure for the removal of symptomatic cysts, minimizing morbidity and mortality relating to the natural history of the disease, as well as possibly avoiding a more extensive standard open craniotomy. A retrospective review of three cases of cisternal cysticercosis was performed. The presenting signs and symptoms, neuroimaging findings, endoscopic treatment, and outcomes are presented. The technical aspect of the endoscopic resection is described, with visual support provided by intraoperative video. Cerebrospinal fluid shunt placement was avoided in one patient in whom complete resection of the cyst was required. In one patient there were extensive interhemispheric and premesencephalic cisternal cysts, some of which could not be removed because of their multiplicity and extensive adhesions. Despite the intraoperative rupture of cysts, there were no cases of arachnoiditis or ventriculitis postoperatively. The minimally invasive endoscopic resection of cisternal cysticercosis is possible and effective in selected patients. Although the most appropriate treatment of cisternal cysticercosis remains a controversial issue, endoscopic resection should be considered as a primary treatment in symptomatic patients in cases that are amenable to endoscopic intervention.

Rosai-Dorfman disease manifesting as intracranial and intraorbital lesion.

Rosai-Dorfman disease is a rare benign idiopathic histioproliferative disorder usually manifesting as massive painless adenopathy. Extranodal involvement of the Central Nervous System (CNS) mimicking a skull base meningioma is rare. A 42-year-old male presented with painless, progressive left visual loss of 4 months duration. Clinically, he had a left ptosis, proptosis and ophthalmoplegia. Magnetic Resonance Imaging (MRI) of the brain with gadolinium revealed a destructive lesion of the left orbital apex, middle cranial fossa and cavernous sinus. He was treated with corticosteroids and underwent debulking. Pathology showed inflammatory infiltrate in the absence of an infectious agent, emperipolesis and a positive S100 stain was consistent with Rosai-Dorfman disease. As there was no improvement following steroids and debulking, he underwent radiation therapy with significant improvement of his symptoms. Although a rare entity, Rosai-Dorfman disease should be considered in the differential of a skull base lesion.