Undergoing Brain Tumor Surgery Research Articles

BIOM-01. CARBONIC ANHYDRASE IX INTERPLAY WITH LOCAL AND SYSTEMIC IMMUNE RESPONSE IN PEDIATRIC BRAIN TUMORS

Abstract BACKGROUND Brain tumors (BT) remain the leading cause of death among childhood cancers. There is an urgent need to identify novel targets in these patients. BT progression depends on the adaptive responses to hypoxia. Carbonic anhydrase IX (CAIX) helps cancer cells survive in a hypoxic environment and can be potentially as a therapeutic target. The role of CAIX in the interplay between the tumor and immune cells requires in-depth investigation to design effective therapies. METHODS Fresh BT, blood, and intraoperative cerebrospinal fluid (iCSF) samples were collected prospectively from pediatric patients, who underwent brain tumor surgery at Vilnius University Hospital Santaros Klinikos from March 2022 to December 2023. All tumor types were included. Immunohistochemistry (IHC) and flow cytometry (FC) were performed to analyze the expression of CAIX and selected immunological markers in the fresh tumor, iCSF and peripheral blood mononuclear cells (PBMCs). Soluble CAIX content in serum and iCSF was assessed by ELISA. In addition, a retrospective analysis of previously diagnosed pediatric glioma specimens was performed by IHC. RESULTS Twelve patients with heterogeneous BT types have been enrolled prospectively and 17 patients with glioma were reviewed retrospectively. Glioma accounted for 72% (21/29) of all samples. IHC showed that 57% of gliomas were positive for CAIX as well as a moderate correlation between the CAIX score and the expression of CD44, CD206, and CCR2 markers. PD-1/PD-L1 expression was negligible. In the prospective cohort, 83% (10/12) of BT tissue was positive for CAIX by IHC and FC. Soluble CAIX was detectable in 40% of iCSF samples, but not in serum. We found a correlation trend of CAIX expression in the fresh tumor cells and iCSF with increased CCR2 expression on CD45+ PBMCs. CONCLUSIONS This interim analysis showed a correlation between CAIX tumor expression and immune biomarkers, prompting further investigation by enrolling more patients.

Nutritional status and clinical outcomes of brain tumor surgery in pediatric intensive care unit: A prospective cohort study

To determine whether nutritional status affects mortality and length of stay in the pediatric intensive care unit (PICU) after brain tumor surgery. Subjects aged 2 months to 13 years with brain tumor surgery were included in the study. Z-scores of BMI for age, weight for age, and weight for length were calculated at admission. Undernutrition was defined as Z-score<-2. Nutritional intake was measured daily by a clinical nutritionist. Outcomes to be measured included duration of hospitalization and mortality. Regression analyses was used to investigate the relationship between nutritional variables and outcomes. A total of 63 patients met the inclusion criteria. Undernutrition at admission was found in 33% of subjects based on Z-scores of BMI and weight for length. The mortality rate was 17.5%. Calorie and protein intake was <50% of the target in 50.7% and 42.8 % of children, respectively. Undernutrition by weight for age Z-score, BMI for age and weight for length Z-scores, and low protein intake increased mortality risk by 5, 5.9 and 4.7 times, respectively. The risk of shorter PICU-free days was independently 80% and 90% lower in those receiving <50% of protein and calorie requirements. Undernutrition at admission is prevalent in children undergoing brain tumor surgery and is associated with a higher risk of mortality. Caloric and protein intake during hospitalization is generally low, leading to longer PICU stay.

Hydrocephalus following Brain Tumor Surgery: Factors Correlating with Occurrence of Postoperative Hydrocephalus and Predictive Scoring Model.

Hydrocephalus following brain tumor surgery is found, although cause of hydrocephalus is optimally eradicated. This study aimed to investigate factors associated with development of postoperative hydrocephalus that requires shunt procedure and generate predictive scoring model of this condition. Demographic, clinical, radiographic, treatment, laboratory, complication, and postoperative data were collected. Binary logistic regression was used to investigate final model for generating predictive scoring system of postoperative hydrocephalus. A total of 179 patients undergoing brain tumor surgery were included. Forty-five (25.1%) patients had postoperative hydrocephalus that required shunt surgery. In univariate analysis, several factors were found to be associated with postoperative hydrocephalus. Strong predictors of postoperative hydrocephalus revealed in multivariate analysis included tumor recurrence before surgery (odds ratio [OR], 4.38; 95% confidence interval [CI], 1.28-14.98; p = 0.018), preoperative hydrocephalus (OR, 6.52; 95% CI, 2.44-17.46; p < 0.001), glial tumor (OR, 3.76; 95% CI, 1.14-12.43; p = 0.030), metastasis (OR, 5.19; 95% CI, 1.72-15.69; p = 0.004), intraventricular hemorrhage (OR, 7.08; 95% CI, 1.80-27.82; p = 0.005), and residual tumor volume (OR, 1.05; 95% CI, 1.01-1.09; p = 0.007). A cutoff predictive score with the best area under curve and optimum cutoff point was utilized for discriminating patients with high risk from individuals with low risk in occurrence of postoperative hydrocephalus. This study reported predictive factors strongly associated with development of postoperative hydrocephalus. Predictive scoring system is useful for identifying patients with an increased risk of postoperative hydrocephalus. Patients classified in the high-risk group require closed surveillance of the hydrocephalus.

Linear Scalp Incision in Brain Tumor Surgery: Intraoperative and Postoperative Considerations

BackgroundAlthough the linear scalp incision is commonly used in neurosurgical practice, a systematic study elucidating its pros and cons in a specific surgical setting is lacking. Herein, we analyzed our experience with linear scalp incision in brain tumor surgery and the impact on intra-operative variables and post-operative complications. MethodsPatients undergoing brain tumor surgery (January 2014-December 2021) at two neurosurgical departments were included and divided into two groups: linear or flap scalp incision. Patients’ demographics characteristics, surgical variables and wound related complications were analyzed. ResultsOver a total of 1036 craniotomies, linear incision (mean length 6cm) was adopted in 282 procedures (27.2 %). Mean maximum diameter of the craniotomy was 5.25 cm, with no statistical difference between the two groups. In emergency surgery (36 cases), the linear and flap incisions were used indifferently. Linear incision was predominant in supratentorial and suboccipital lesions. Flap incision was significantly more frequent among meningiomas (p<0.01). Neuronavigation, operative microscope, and subgaleal drain were more frequently used in the flap scalp incision group (p=0.01). Overall complication rate was comparable to flap scalp opening (p= 0.40). ConclusionsThe use of the linear incision was broadly applied for the removal of supratentorial and suboccipital tumors granting adequate surgical exposure with a low rate of post-operative complications. Tumors skull base localization resulted the only factor hindering the use of the linear incision. The choice of one incision over another didn’t show to have any impact on intra- and post-operative variables and it remains mainly based on surgeon expertise/preference.

Neurosurgical treatment of pediatric brain tumors - results from a single center multidisciplinary setup

ObjectiveThe challenge of pediatric brain tumor surgery is given due to a relative low prevalence but high heterogeneity in age, localization, and pathology. Improvements of long-term overall survival rates were achieved during the past decades stressing the importance of a multidisciplinary decision process guided by a national treatment protocol. We reviewed the entire spectrum of pediatric brain tumor surgeries from the perspective of an interdisciplinary pediatric neuro-oncology center in Germany.MethodsEvery patient who underwent brain tumor surgery from January 2010 to June 2017 in our Pediatric Neurosurgery department was retrospectively included and evaluated regarding the course of treatment. Perioperative data such as tumor localization, timing of surgery, extent of resection, neuropathological diagnosis, transfusion rates, oncologic and radiation therapy, and neurological follow-up including morbidity and mortality were evaluated.ResultsTwo hundred ninety-three pediatric brain tumor patients were applicable (age: 8.28 ± 5.62 years, 1.22:1.0 m:f). A total of 531 tumor surgical interventions was performed within these patients (457 tumor resections, 74 tumor biopsies; mean interventions per patient 1.8 ± 1.2). Due to a critical neurologic status, 32 operations (6%) were performed on the day of admission. In 65.2% of all cases, tumor were approached supratentorially. Most frequent diagnoses of the cases were glial tumors (47.8%) and embryonal tumors (17.6%). Preoperative planned extent of resection was achieved in 92.7%. Pre- and postoperative neurologic deficits resolved completely in 30.7%, whereas symptom regressed in 28.6% of surgical interventions. New postoperative neurologic deficit was observed in 10.7%, which resolved or improved in 80% of these cases during 30 days. The mortality rate was 1%.ConclusionWe outlined the center perspective of a specialized pediatric neuro-oncological center describing the heterogeneous distribution of cases regarding age-related prevalence, tumor localization, and biology, which requires a high multidisciplinary expertise. The study contributes to define challenges in treating pediatric brain tumors and to develop quality indicators for pediatric neuro-oncological surgery. We assume that an adequate volume load of patients within a interdisciplinary infrastructure is warranted to aim for effective treatment and decent quality of life for the majority of long-term surviving pediatric tumor patients.

The Effect of Postoperative Pain on Sleep Quality in Patients with Brain Tumor Surgery

This descriptive study investigated the effect of postoperative pain on sleep quality in patients who underwent brain tumor surgery in neurosurgical clinics.The study population consisted of all patients who underwent surgery for a brain tumor between April and October 2022 in the neurosurgical units of a university hospital and a city hospital. The sample consisted of 90 volunteers. Data were collected using a patient information form, the Numerical Rating Scale for Pain (NRS), and the Richards-Campbell Sleep Scale (RCSQ). The data were analyzed using the number, percentage, mean, standard deviation, correlation, and regression analysis. Participants had a mean age of 47.36±16.17 years. Half of the participants were men (50%). Less than half of the participants had a primary school degree (44.4%). Most participants were married (82.2%). Less than half of the participants slept ≥8 hours before hospitalization (43.3%). Most participants had no sleep problems (88.9%) and were not on sleeping pills (98.8%). Participants’ pain scores significantly differed by measurement times (ꭓ2=60.715; p=0.000). They had significantly lower mean second- (4.20±2.58) and third-measurement (3.13±2.36) NRS scores than the first-measurement NRS score (5.57±2.83) in the morning. In the morning, they had a significantly lower mean third-measurement NRS score (3.13±2.36) than the second-measurement NRS score (4.20±2.58). There was a weak negative correlation between the mean first-measurement RCSQ score and the first-measurement NRS (morning) and NRS (evening) scores (p&lt;0.05).There is a negative correlation between sleep quality and pain in patients who underwent surgery for a brain tumor

P19.05.A THE NEURONAL CORRELATES OF BRAIN TUMOR ASSOCIATED SEIZURES IN HUMAN AND MOUSE PERITUMORAL CORTEX

Abstract BACKGROUND The occurrence of seizures is the most common comorbidity in malignant brain tumors. Recent advancements in the field of cancer neuroscience indicate that seizures can potentially influence brain tumor progression through intricate neuron-glioma interactions in the peritumoral infiltrated cortex of glioma patients. Therefore, understanding not only the tumor processes but also the neuronal properties in the tumor microenvironment could provide key insights into the relationship between epilepsy and tumor progression. To investigate this, we conducted a study to characterize neuronal alterations in glioma infiltrated neocortex of both patients and a glioma mouse model. MATERIAL AND METHODS Infiltrated peritumoral cortex was obtained from both epileptic and non-epileptic patients undergoing brain tumor surgery. Ex vivo brain slices were prepared and single-cell electrophysiology was performed on peritumoral neurons. High grade gliomas were induced into compound LoxP-conditional mice via stereotactic viral injection in combination with serial electro-corticographic activity to monitor epileptogenesis. RESULTS Ex vivo recordings from infiltrated human peritumoral cortex revealed electrophysiological and morphological alterations in neocortical neurons of patients experiencing seizures. Using an inducible immunocompetent high-grade glioma mouse model, we tracked the progression of cortical epileptogenesis during tumor infiltration. We observed several spatial and temporal changes in the peritumoral cortex of glioma mice, including progressive glial reaction and gradual neuronal reduction. We also identified intrinsic and network alterations in the cortical neurons of glioma mouse model, consistent with the electrophysiological characteristics of human peritumoral cortex prior to seizure onset. CONCLUSION Overall, our study demonstrated dynamic electrophysiological and histological changes in human and mouse peritumoral cortex during the course of tumor progression and epileptogenesis. These findings provide important insights into brain tumor associated seizures and cast light on new therapeutical targets for treatments.

Intraoperative microscopic autofluorescence detection and characterization in brain tumors using stimulated Raman histology and two-photon fluorescence.

The intrinsic autofluorescence of biological tissues interferes with the detection of fluorophores administered for fluorescence guidance, an emerging auxiliary technique in oncological surgery. Yet, autofluorescence of the human brain and its neoplasia is sparsely examined. This study aims to assess autofluorescence of the brain and its neoplasia on a microscopic level by stimulated Raman histology (SRH) combined with two-photon fluorescence. With this experimentally established label-free microscopy technique unprocessed tissue can be imaged and analyzed within minutes and the process is easily incorporated in the surgical workflow. In a prospective observational study, we analyzed 397 SRH and corresponding autofluorescence images of 162 samples from 81 consecutive patients that underwent brain tumor surgery. Small tissue samples were squashed on a slide for imaging. SRH and fluorescence images were acquired with a dual wavelength laser (790 nm and 1020 nm) for excitation. In these images tumor and non-tumor regions were identified by a convolutional neural network that reliably differentiates between tumor, healthy brain tissue and low quality SRH images. The identified areas were used to define regions.of- interests (ROIs) and the mean fluorescence intensity was measured. In healthy brain tissue, we found an increased mean autofluorescence signal in the gray (11.86, SD 2.61, n=29) compared to the white matter (5.99, SD 5.14, n=11, p<0.01) and in the cerebrum (11.83, SD 3.29, n=33) versus the cerebellum (2.82, SD 0.93, n=7, p<0.001), respectively. The signal of carcinoma metastases, meningiomas, gliomas and pituitary adenomas was significantly lower (each p<0.05) compared to the autofluorescence in the cerebrum and dura, and significantly higher (each p<0.05) compared to the cerebellum. Melanoma metastases were found to have a higher fluorescent signal (p<0.01) compared to cerebrum and cerebellum. In conclusion we found that autofluorescence in the brain varies depending on the tissue type and localization and differs significantly among various brain tumors. This needs to be considered for interpreting photon signal during fluorescence-guided brain tumor surgery.

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Glycaemic Response to Intraoperative Dexamethasone in Non-Diabetic Patients Undergoing Brain Tumor Surgery

Risk factors and the nomogram model for intraoperatively acquired pressure injuries in children with brain tumours: A retrospective study.

This study aimed to investigate the clinical features and incidence of Intraoperatively Acquired Pressure Injuries (IAPIs) of brain tumours in children, to screen the risk factors and to establish a nomogram model for making prevention strategies against the development of IAPIs. Clinical data of 628 children undergoing brain tumour surgery from August 2019 to August 2021 were extracted from the adverse events and the electronic medical systems. They were randomly divided into a training cohort(n = 471) and a validation cohort(n = 157). The univariate and multivariate analysis was performed to identify the risk factors in training cohort; R software was used to construct a nomogram model; the area under the receiver operator characteristic curve (AUC) and calibration plots were used to judge the predictive performance of the nomogram model; decision curve analysis (DCA) was used to assess the clinical usefulness of the nomogram model. Age, haemorrhage, use of vasopressor, temperature, operation time and operation position were considered as significant risk factors, and enrolled to construct a nomogram model. The results of AUC showed satisfactory discrimination of the nomogram; the calibration plots indicated favourable consistency between the prediction of the nomogram and actual observations in both the training and validation cohorts; DCA showed better net benefit and threshold probability of the nomogram model. The nomogram model illustrates significant predictive ability, which can provide scientific and individual guidance for preventing development of IAPIs.

Time to surgery after radiological diagnosis of brain tumours in Pakistan: A nationwide cross-sectional study.

To investigate waiting times for brain tumour surgery in Pakistan from a nationwide sample and highlight specific affected patient populations. A nationwide study was conducted as part of the Pakistan Brain Tumour Epidemiology Study; data from 32 high-volume neurosurgical centres were collected. The national sample included 2,750 patients. Time to surgery was calculated by the difference in dates recorded for radiological diagnosis and the date of the first surgery. This was further stratified according to demographic factors, histopathological diagnosis, type of surgical procedure performed and survival outcomes. The data of 1,474 patients for time to surgery was available. Patients travelling to public hospitals had significantly longer mean wait times (94.07 (CI: 85.29, 102.84) vs 75.14 (CI: 54.72, 95.56) days, p<0.001). Significant differences were seen between patients of various age groups, as adolescents (116.63 (CI: 65.27, 167.98) days) and young adults (103.34 (CI: 85.96, 120.72) days) had higher waiting times compared to middle-aged (72.44 (CI: 61.26, 83.61) days) and older (48.58 (CI: 31.17, 65.98) days) adults. No difference was seen between the genders. A significantly longer time to surgery was observed for middle- and lower-socioeconomic class patients. Those undergoing gross total resection of the tumour had significantly (p<0.001) longer waiting times for surgery when compared to STR (sub-total resection), biopsy, and CSF-diversion procedures, for all tumour types. Patients diagnosed with meningioma had the most prolonged waiting periods (106 (CI: 76, 95) days). Gliomas had a mean waiting period of 88 (CI: 73, 103) days across the country. Low-grade gliomas had significantly (p=0.031) longer mean waiting times (99.73 (CI: 61.91, 127.36) days) in comparison to high-grade gliomas (70.13 (CI: 43.39, 89.69 ) days). A significant difference was seen between waiting times for patients who survived surgical procedures for a brain tumour on the most recent follow-up and those who had expired (91.87 (CI: 79, 107.74) vs 77.41 (CI: 59.90, 94.91) days, p<0.001). Prolonged delays to surgery are a significant barrier within low-and-middle-income countries, leading to adverse outcomes for patients. Patients undergoing brain tumour surgery at public hospitals from lower or middle SES and electing for gross resections were more likely to have longer delays.

QLTI-21. SAFETY OF THE UTILIZATION OF TELEMEDICINE FOR BRAIN TUMOR NEUROSURGERY FOLLOW-UP

Abstract BACKGROUND There is a need to evaluate the outcomes of patients who underwent brain tumor surgery and were followed by telemedicine or in-person consults during the COVID-19 pandemic. METHODS We retrospectively included all patients who underwent surgery for brain tumor resection by a single neurosurgeon at our Institution from the beginning of the COVID-19 pandemic restrictions (March 2020) to August 2021. Outcomes were assessed by stratifying the patients using their preference for follow-up method (telemedicine or in-person). RESULTS Three-hundred and eighteen (318) brain tumor patients who were included. The follow-up method of choice was telemedicine in 185 patients (58.17%), and in-person consults in 133 patients. We found that patients followed by telemedicine lived significantly farther, with a median of 22.23 miles, compared to a median of 36.34 miles in the TM cohort (p = 0.0025). When comparing visits to the emergency department (ED) within 30 days after surgery, and we found no statistical difference between the TM and the IP group (7.3% vs 6.01%, p=0.72). Readmission rates, wound infections and 30-day mortality were similar in both cohorts. These findings were also consistent after matching cohorts using a propensity score. The percentage of telemedicine follow-up consults was higher in the first semester (73.17%) of the COVID-19 pandemic, compared to the second (46.21%) and third semesters (47.86%). CONCLUSIONS Telehealth follow-up alternatives may be safely offered to patients after brain tumor surgery, thereby reducing patient burden in those with longer distances to the hospital or special situations as the COVID-19 pandemic.

QLTI-13. FEASIBILITY OF SAMEDAY DISCHARGE AFTER BRAIN TUMOR RESECTION: A PROSPECTIVE QUALITY INTERVENTION STUDY

Abstract INTRODUCTION Cranial neurosurgery confers psychological stress, as well as the stress of being in the hospital rather than in one’s preferred surroundings. Compared with inpatient admissions, same-day discharges reduce patient exposure to nosocomial infection, thromboembolic complications, and medical error. Also, it reduces costs to the health care system. OBJECTIVE To report the results of a pilot study that prospectively evaluated for the first time in a United States hospital, the outcomes of patients that underwent brain tumor surgery and are discharged home the same day as surgery. METHODS A quality intervention study including patients who underwent outpatient craniotomy for brain tumors by a single neurosurgeon (R.J.K) at the University of Miami from August 2020 to August 2021 was performed. Patients included were between 16 to 85 years old, with a Karnofsky Performance Status score of ≥ 70, and with supratentorial tumors with a maximum diameter of 4 cm. Complete demographic and clinical data were collected prospectively for each patient. In all patients, the minimum observation period was 6 h after surgery. RESULTS 37 of 334 patients met the inclusion criteria for the outpatient protocol. Thirty-two patients were discharged on the same day as surgery. Five patients (14%) were considered eligible for outpatient surgery but were ultimately admitted to the hospital postoperatively and were discharged after overnight observation. No postoperative complications were noted at two-week follow-up. CONCLUSION With appropriate selection and postoperative monitoring, same-day discharge can be considered a safe and feasible option for certain craniotomy cases. Establishing a multidisciplinary team of physicians, nurses, radiologists, and physical therapists is critical to achieving this aim. Physicians should have a low threshold to admit a patient with concerning exam findings, complications, or complicated past medical history

The Comprehensive Complication Index (CCI) as a Measure of Postoperative Morbidity and Neurological Outcome after Elective Intracranial Surgery.

The Comprehensive Complication Index (CCI) is a numerical scale based on the Clavien-Dindo classification (CDC) and both are widely used to assess outcome. However, the CCI had not been described for neurosurgical procedures. We aimed to investigate the value of the CCI to predict outcome in patients who underwent elective intracranial surgery. Prospective cohort study including patients who underwent elective intracranial surgery. Complications were graded using CDC, and the CCI was calculated daily. Neurological outcome was assessed using mRS, NANO, NIHSS, and KPS. Of 294 patients who underwent an elective intracranial procedure, 211 (71.8%) patients underwent a craniotomy, while 28 (9.5%) patients had a burr hole procedure and 55 (18.7%) patients a transsphenoidal approach. A higher blood loss was the only significant predictor for a higher CCI (OR 1.09, 95% CI 1.00-1.12, P < 0.01). Patients with a higher CCI had a longer LOS (mean: 5.4 versus 10.9 days, P < 0.01) and ICU stay (mean: 0.8 versus 2.4 days, P < 0.01). Daily CCI revealed a risk for complications after craniotomies until postoperative day (POD) 7. In patients who underwent brain tumor surgery, the resection of meningiomas and metastasis showed a similar developmental course of CCI. A significantly higher CCI was observed in patients who had a neurological deterioration at discharge ( P < 0.01). CCI is a valid scale to measure outcome after intracranial procedures and correlates with neurological outcome. Risk for adverse events after craniotomy is at highest until postoperative day 7.

네비게이션 시스템을 이용한 증강현실의 개별화된 뇌종양 수술

Background : With the recent development of augmented reality (AR) systems, it has become possible to implement three-dimensional (3D) images directly with a microscope using a navigation system. The authors would like to show how this AR system is used in brain tumor surgery. Materials and Methods : From November 2020 to August 2021, consecutive patients who underwent brain tumor surgery were enrolled in this study. Preoperatively, magnetic resonance imaging (MRI) was obtained using a 3-Tesla scanner. Surrounding significant structures were segmented from MRI. Segmented objects were stored as analyzed images and imported into the navigation system. During the operation, a neuro-navigation system and a microscope were linked and applied. Through the eyepiece of the microscope, segmented objects could be overlaid in AR format on the actual operative field. Results : Thirty-four cases were enrolled in the study. Patients comprised 19 male patients and 15 female patients. The median age was 60 years (range, 36-81 years); 11 cases were meningiomas, 10 cases were metastatic brain tumors, 8 cases were glioblastomas, 2 were hemangioblastomas, and there were 1 ependymoma, 1 giant pituitary adenoma, and 1 primary intracranial lymphoma. All cases were resected gross totally, except two cases (one glioblastoma, and one giant pituitary adenoma). There was no postoperative hemorrhage or infection. Conclusions : Brain tumor surgery using the AR system can increase the convenience of surgery by providing intuitive information to the surgeon. The AR system may become an invaluable tool in delivering safer care to brain tumor patients.