Response of treatment-naive brain metastases to stereotactic radiosurgery.

With improvements in survival for patients with metastatic cancer, long-term local control of brain metastases has become an increasingly important clinical priority. While consensus guidelines recommend surgery followed by stereotactic radiosurgery (SRS) for lesions >3 cm, smaller lesions (≤3 cm) treated with SRS alone elicit variable responses. To determine factors influencing this variable response to SRS, we analyzed outcomes of brain metastases ≤3 cm diameter in patients with no prior systemic therapy treated with frame-based single-fraction SRS. Following SRS, 259 out of 1733 (15%) treated lesions demonstrated MRI findings concerning for local treatment failure (LTF), of which 202 /1733 (12%) demonstrated LTF and 54/1733 (3%) had an adverse radiation effect. Multivariate analysis demonstrated tumor size (>1.5 cm) and melanoma histology were associated with higher LTF rates. Our results demonstrate that brain metastases ≤3 cm are not uniformly responsive to SRS and suggest that prospective studies to evaluate the effect of SRS alone or in combination with surgery on brain metastases ≤3 cm matched by tumor size and histology are warranted. These studies will help establish multi-disciplinary treatment guidelines that improve local control while minimizing radiation necrosis during treatment of brain metastasis ≤3 cm.

Repeated blood-brain barrier opening with a nine-emitter implantable ultrasound device in combination with carboplatin in recurrent glioblastoma: a phase I/II clinical trial.

Here, the results of a phase 1/2 single-arm trial (NCT03744026) assessing the safety and efficacy of blood-brain barrier (BBB) disruption with an implantable ultrasound system in recurrent glioblastoma patients receiving carboplatin are reported. A nine-emitter ultrasound implant was placed at the end of tumor resection replacing the bone flap. After surgery, activation to disrupt the BBB was performed every four weeks either before or after carboplatin infusion. The primary objective of the Phase 1 was to evaluate the safety of escalating numbers of ultrasound emitters using a standard 3 + 3 dose escalation. The primary objective of the Phase 2 was to evaluate the efficacy of BBB opening using magnetic resonance imaging (MRI). The secondary objectives included safety and clinical efficacy. Thirty-three patients received a total of 90 monthly sonications with carboplatin administration and up to nine emitters activated without observed DLT. Grade 3 procedure-related adverse events consisted of pre syncope (n = 3), fatigue (n = 1), wound infection (n = 2), and pain at time of device connection (n = 7). BBB opening endpoint was met with 90% of emitters showing BBB disruption on MRI after sonication. In the 12 patients who received carboplatin just prior to sonication, the progression-free survival was 3.1 months, the 1-year overall survival rate was 58% and median overall survival was 14.0 months from surgery.

Subependymomas of the fourth ventricle: To operate or not to operate?

BACKGROUND: There is a paucity of literature regarding the clinical characteristics and management of subependymomas of the fourth ventricle due to their rarity. Here, we describe the operative and non-operative management and outcomes of patients with such tumors. METHODS: This retrospective single-institution case series was gathered after Institutional Review Board (IRB) approval. Patients diagnosed with a subependymoma of the fourth ventricle between 1993 and 2021 were identified. Clinical, radiology and pathology reports along with magnetic resonance imaging (MRI) images were reviewed. RESULTS: Patients identified (n = 20), showed a male predominance (n = 14). They underwent surgery (n = 9) with resection and histopathological confirmation of subependymoma or were followed with imaging surveillance (n = 11). The median age at diagnosis was 51.5 years. Median tumor volume for the operative cohort was 8.64 cm3 and median length of follow-up was 65.8 months. Median tumor volume for the non-operative cohort was 0.96 cm3 and median length of follow-up was 78 months. No tumor recurrence post-resection was noted in the operative group, and no tumor growth from baseline was noted in the non-operative group. Most patients (89 %) in the operative group had symptoms at diagnosis, all of which improved post-resection. No patients were symptomatic in the non-operative group. CONCLUSIONS: Surgical resection is safe and is associated with alleviation of presenting symptoms in patients with large tumors. Observation and routine surveillance are warranted for smaller, asymptomatic tumors.

Study Protocol STEREOLAB: Stereotactic Liver Ablation Assisted with Intra-Arterial CT Hepatic Arteriography and Ablation Confirmation Software Assessment.

PURPOSE: This study aims to evaluate the technical efficacy and local tumor progression-free survival (LTPFS) of a standardized workflow for thermal ablation of colorectal liver metastases (CRLM) consisting of CT during hepatic arteriography (CTHA)-based imaging analysis, stereotactic thermal ablation, and computer-based software assessment of ablation margins. MATERIALS AND METHODS: This investigator initiated, single-center, single-arm prospective trial will enroll up to 50 patients (≤ 5 CRLM, Measuring ≤ 5 cm). Procedures will be performed in an angio-CT suite under general anesthesia. The primary objective is to estimate LTPFS with a follow-up of up to 2 years and secondary objectives are analysis of the impact of minimal ablative margins on LTPFS, adverse events, contrast media utilization and radiation exposure, overall oncological outcomes, and anesthesia/procedural time. Adverse events (AE) will be recorded by CTCAE (Common Toxicity Criteria for Adverse Events), and Bayesian optimal phase-2 design will be applied for major intraprocedural AE stop boundaries. The institutional CRLM ablation registry will be used as benchmark for comparative analysis with the historical cohort. DISCUSSION: The STEREOLAB trial will introduce a high-precision and standardized thermal ablation workflow for CRLM consisting of CT during hepatic arteriography imaging, stereotactic guidance, and ablation confirmation. Trial Registration ClinicalTrials.gov identifier: (NCT05361551).

Nivolumab and ipilimumab with concurrent stereotactic radiosurgery for intracranial metastases from non-small cell lung cancer: analysis of the safety cohort for non-randomized, open-label, phase I/II trial.

BACKGROUND: Up to 20% of patients with non-small cell lung cancer (NSCLC) develop brain metastasis (BM), for which the current standard of care is radiation therapy with or without surgery. There are no prospective data on the safety of stereotactic radiosurgery (SRS) concurrent with immune checkpoint inhibitor therapy for BM. This is the safety cohort of the phase I/II investigator-initiated trial of SRS with nivolumab and ipilimumab for patients with BM from NSCLC. PATIENTS AND METHODS: This single-institution study included patients with NSCLC with active BM amenable to SRS. Brain SRS and systemic therapy with nivolumab and ipilimumab were delivered concurrently (within 7 days). The endpoints were safety and 4-month intracranial progression-free survival (PFS). RESULTS: Thirteen patients were enrolled in the safety cohort, 10 of whom were evaluable for dose-limiting toxicities (DLTs). Median follow-up was 23 months (range 9.7-24.3 months). The median interval between systemic therapy and radiation therapy was 3 days. Only one patient had a DLT; hence, predefined stopping criteria were not met. In addition to the patient with DLT, three patients had treatment-related grade ≥3 adverse events, including elevated liver function tests, fatigue, nausea, adrenal insufficiency, and myocarditis. One patient had a confirmed influenza infection 7 months after initiation of protocol treatment (outside the DLT assessment window), leading to pneumonia and subsequent death from hemophagocytic lymphohistiocytosis. The estimated 4-month intracranial PFS rate was 70.7%. CONCLUSION: Concurrent brain SRS with nivolumab/ipilimumab was safe for patients with active NSCLC BM. Preliminary analyses of treatment efficacy were encouraging for intracranial treatment response.

Retrospective Analysis of Imaging Characteristics of Tectal Gliomas.

BACKGROUND AND PURPOSE: Tectal gliomas (TGs) are rare tumors that involve critical locations in the brainstem, including the superior and inferior colliculi and the Sylvian aqueduct. The rarity of these tumors and the lack of large clinical studies have hindered adequate understanding of this disease. We sought to determine the association between imaging characteristics of TG and progression-free survival (PFS). MATERIALS AND METHODS: In this retrospective cohort study, impact of imaging characteristics (contrast enhancement, calcifications, cystic changes, presence of hydrocephalus) on survival was analyzed for 39 patients with TG. We used the Kaplan-Meier survival analysis method for determining the association between imaging characteristics and PFS. Progression-free survival was measured from time of diagnosis to radiographic or pathological disease progression during observation period. Progression was defined as more than 25% increase of the lesion in size, per response assessment in neuro-oncology, together with clinical deterioration and/or a need for intervention. Progression-free survival differences by various imaging characteristics were assessed using the log-rank test and univariable Cox proportional hazard regression. Because most of the studies in the current literature tend to overrepresent pediatric patients, we aimed to determine the association between TG tumors' imaging characteristics and PFS in both adult and pediatric patients. All statistical analyses were performed using STATA version 16.1 (Stata Corp, College Station, Tex). RESULTS: Of the 39 patients, radiographic tumor progression was observed in 15 cases (38.5%). Median PFS for 39 patients during observation was 21.8 years. Tectal gliomas that showed contrast enhancement initially or developed contrast enhancement during surveillance on magnetic resonance imaging had significantly lower PFS than those without (hazard ratio, 3.55; 95% confidence interval, 1.09-11.58; log-rank P value, 0.02). CONCLUSIONS: Analysis of this patient population showed that contrast-enhancing TGs should not be categorically defined as benign lesions. This subgroup of patients should be followed closely for signs of progression.

Changes in outcomes and factors associated with survival in melanoma patients with brain metastases.

BACKGROUND: Treatment options for patients with melanoma brain metastasis (MBM) have changed significantly in the last decade. Few studies have evaluated changes in outcomes and factors associated with survival in MBM patients over time. The aim of this study is to evaluate changes in clinical features and overall survival (OS) for MBM patients. METHODS: Patients diagnosed with MBMs from 1/1/2009 to 12/31/2013 (Prior Era; PE) and 1/1/2014 to 12/31/2018 (Current Era; CE) at The University of Texas MD Anderson Cancer Center were included in this retrospective analysis. The primary outcome measure was OS. Log-rank test assessed differences between groups; multivariable analyses were performed with Cox proportional hazards models and recursive partitioning analysis (RPA). RESULTS: A total of 791 MBM patients (PE, n = 332; CE, n = 459) were included in analysis. Median OS from MBM diagnosis was 10.3 months (95% CI, 8.9-12.4) and improved in the CE vs PE (14.4 vs 10.3 months, P < .001). Elevated serum lactate dehydrogenase (LDH) was the only factor associated with worse OS in both PE and CE patients. Factors associated with survival in CE MBM patients included patient age, primary tumor Breslow thickness, prior immunotherapy, leptomeningeal disease, symptomatic MBMs, and whole brain radiation therapy. Several factors associated with OS in the PE were not significant in the CE. RPA demonstrated that elevated serum LDH and prior immunotherapy treatment are the most important determinants of survival in CE MBM patients. CONCLUSIONS: OS and factors associated with OS have changed for MBM patients. This information can inform contemporary patient management and clinical investigations.

An interdisciplinary consensus on the management of brain metastases in patients with renal cell carcinoma.

Brain metastases are a challenging manifestation of renal cell carcinoma. We have a limited understanding of brain metastasis tumor and immune biology, drivers of resistance to systemic treatment, and their overall poor prognosis. Current data support a multimodal treatment strategy with radiation treatment and/or surgery. Nonetheless, the optimal approach for the management of brain metastases from renal cell carcinoma remains unclear. To improve patient care, the authors sought to standardize practical management strategies. They performed an unstructured literature review and elaborated on the current management strategies through an international group of experts from different disciplines assembled via the network of the International Kidney Cancer Coalition. Experts from different disciplines were administered a survey to answer questions related to current challenges and unmet patient needs. On the basis of the integrated approach of literature review and survey study results, the authors built algorithms for the management of single and multiple brain metastases in patients with renal cell carcinoma. The literature review, consensus statements, and algorithms presented in this report can serve as a framework guiding treatment decisions for patients. CA Cancer J Clin. 2022;72:454-489.

Assessing mobility in primary brain tumor patients: A descriptive feasibility study using two established mobility tests.

Background: Patients with primary brain tumors (PBT) face significant mobility issues related to their disease and/or treatment. Here, the authors describe the preliminary utility and feasibility of two established mobility measures, the Timed-Up-and-Go (TUG) and Five-Times Sit-to-Stand (TSS) tests, in quickly and objectively assessing the mobility status of PBT patients at a single institution's neuro-oncology clinic. Methods: Adult patients undergoing routine PBT care completed the TUG/TSS tests and MD Anderson Symptom Inventory-Brain Tumor module (MDASI-BT), which assessed symptom burden and interference with daily life, during clinic visits over a 6-month period. Research staff assessed feasibility metrics, including test completion times/rates, and collected demographic, clinical, and treatment data. Mann-Whitney tests, Kruskal-Wallis tests, and Spearman's rho correlations were used to interrogate relationships between TUG/TSS test completion times and patient characteristics. Results: The study cohort included 66 PBT patients, 59% male, with a median age of 47 years (range: 20-77). TUG/TSS tests were completed by 62 (94%) patients. Older patients (P < .001) and those who were newly diagnosed (P = .024), on corticosteroids (P = .025), or had poor (≤80) KPS (P < .01) took longer to complete the TUG/TSS tests. Worse activity-related (work, activity, and walking) interference was associated with longer TUG/TSS test completion times (P < .001). Conclusions: The TUG/TSS tests are feasible for use among PBT patients and may aid in clinical care. Older age, being newly diagnosed, using corticosteroids, poor (≤80) KPS, and high activity-related interference were associated with significant mobility impairment, highlighting the tests' potential clinical utility. Future investigations are warranted to longitudinally explore feasibility and utility in other practice and disease settings.

Circumferential sulcus-guided resection technique for improved outcomes of low-grade gliomas.

OBJECTIVE: Many neurosurgeons resect nonenhancing low-grade gliomas (LGGs) by using an inside-out piecemeal resection (PMR) technique. At the authors' institution they have increasingly used a circumferential, perilesional, sulcus-guided resection (SGR) technique. This technique has not been well described and there are limited data on its effectiveness. The authors describe the SGR technique and assess the extent to which SGR correlates with extent of resection and neurological outcome. METHODS: The authors identified all patients with newly diagnosed LGGs who underwent resection at their institution over a 22-year period. Demographics, presenting symptoms, intraoperative data, method of resection (SGR or PMR), volumetric imaging data, and postoperative outcomes were obtained. Univariate analyses used ANOVA and Fisher's exact test. Multivariate analyses were performed using multivariate logistic regression. RESULTS: Newly diagnosed LGGs were resected in 519 patients, 208 (40%) using an SGR technique and 311 (60%) using a PMR technique. The median extent of resection in the SGR group was 84%, compared with 77% in the PMR group (p = 0.019). In multivariate analysis, SGR was independently associated with a higher rate of complete (100%) resection (27% vs 18%) (OR 1.7, 95% CI 1.1-2.6; p = 0.03). SGR was also associated with a statistical trend toward lower rates of postoperative neurological complications (11% vs 16%, p = 0.09). A subset analysis of tumors located specifically in eloquent brain demonstrated SGR to be as safe as PMR. CONCLUSIONS: The authors describe the SGR technique used to resect LGGs and show that SGR is independently associated with statistically significantly higher rates of complete resection, without an increase in neurological complications, than with PMR. SGR technique should be considered when resecting LGGs.

Long term outcomes following surgery for pineal region tumors.

PURPOSE: Pineal region tumors are surgically demanding tumors to resect. Long term neuro-oncologic outcomes following surgical excision of tumors from this region have been underreported. We sought to define the long term outcomes of patients undergoing resection of pineal region tumors. METHODS: A retrospective analysis of a prospectively maintained database was performed on patients who underwent intended surgical excision of pineal region tumors. Overall survival (OS) and progression free survival (PFS) were the primary endpoints of this study. Factors associated with OS, PFS and the degree of resection were analyzed, along with 30-day complication rates and dependence on CSF diversion. RESULTS: Sixty-eight patients with a mean age of 30.9 ± 15.3 years were analyzed. The median clinical and radiographic follow-up was 95.7 and 48.2 months, respectively. The supracerebellar infratentorial and the occipital transtentorial corridors were utilized in the majority of cases (80.9%). The gross total resection (GTR) rate was 52.9% (n=36). The 5-year OS and PFS rates were 70.2% and 58.5%, respectively. Achieving GTR was associated with improved OS (HR 0.39, p = 0.03) and PFS (HR 0.4, p = 0.006). The 30-day mortality rate was 5.9%. The need for CSF diversion was high with 77.9% of patients requiring a shunt or ETV by last follow-up. CONCLUSIONS: This is the first modern surgical series providing long term follow-up for patients undergoing surgical resection of pineal region tumors. Obtaining a GTR of these challenging tumors is beneficial with regards to PFS/OS. Higher grade tumors have diminished PFS/OS and are treated with adjuvant chemotherapy and/or radiotherapy.

Middle meningeal artery embolization for chronic subdural hematoma in cancer patients with refractory thrombocytopenia.

OBJECTIVE: Surgical evacuation of chronic subdural hematoma (SDH) in cancer patients is often contraindicated owing to refractory thrombocytopenia. Middle meningeal artery embolization (MMAE) recently emerged as a potential alternative to surgical evacuation for patients with chronic SDH. The goal of this study was to evaluate the safety and efficacy of MMAE for chronic SDH in cancer patients with refractory thrombocytopenia. METHODS: A multiinstitutional registry was reviewed for clinical and radiographic outcomes of cancer patients with transfusion-refractory thrombocytopenia and baseline platelet count < 75 K/µl, who underwent MMAE for chronic SDH. RESULTS: MMAE was performed on a total of 31 SDHs in 22 patients, with a mean ± SD (range) platelet count of 42.1 ± 18.3 (9-74) K/µl. At the longest follow-up, 24 SDHs (77%) had reduced in size, with 15 (48%) showing > 50% reduction. Two patients required surgical evacuation after MMAE. There was only 1 procedural complication; however, 16 patients (73%) ultimately died of cancer-related complications. Median survival was significantly longer in the 16 patients with improved SDH than the 6 patients with worsened SDH after MMAE (185 vs 24 days, p = 0.029). Length of procedure, technical success rate, SDH size reduction, and complication rate were not significantly differ between patients who underwent transfemoral and transradial approaches. CONCLUSIONS: Transfemoral or transradial MMAE is a potential therapeutic option for thrombocytopenic cancer patients with SDH. However, treatment benefit may be marginal for patients with high disease burden and limited life expectancy. A prospective trial is warranted to address these questions.

Treatment for Brain Metastases: ASCO-SNO-ASTRO Guideline.

PURPOSE: To provide guidance to clinicians regarding therapy for patients with brain metastases from solid tumors. METHODS: ASCO convened an Expert Panel and conducted a systematic review of the literature. RESULTS: Thirty-two randomized trials published in 2008 or later met eligibility criteria and form the primary evidentiary base. RECOMMENDATIONS: Surgery is a reasonable option for patients with brain metastases. Patients with large tumors with mass effect are more likely to benefit than those with multiple brain metastases and/or uncontrolled systemic disease. Patients with symptomatic brain metastases should receive local therapy regardless of the systemic therapy used. For patients with asymptomatic brain metastases, local therapy should not be deferred unless deferral is specifically recommended in this guideline. The decision to defer local therapy should be based on a multidisciplinary discussion of the potential benefits and harms that the patient may experience. Several regimens were recommended for non-small-cell lung cancer, breast cancer, and melanoma. For patients with asymptomatic brain metastases and no systemic therapy options, stereotactic radiosurgery (SRS) alone should be offered to patients with one to four unresected brain metastases, excluding small-cell lung carcinoma. SRS alone to the surgical cavity should be offered to patients with one to two resected brain metastases. SRS, whole brain radiation therapy, or their combination are reasonable options for other patients. Memantine and hippocampal avoidance should be offered to patients who receive whole brain radiation therapy and have no hippocampal lesions and 4 months or more expected survival. Patients with asymptomatic brain metastases with either Karnofsky Performance Status ≤ 50 or Karnofsky Performance Status < 70 with no systemic therapy options do not derive benefit from radiation therapy.Additional information is available at www.asco.org/neurooncology-guidelines.

Viscoelastic biomechanical models to predict inward brain-shift using public benchmark data.

Brain-shift during neurosurgery compromises the accuracy of tracking the boundaries of the tumor to be resected. Although several studies have used various finite element models (FEMs) to predict inward brain-shift, evaluation of their accuracy and efficiency based on public benchmark data has been limited. This study evaluates several FEMs proposed in the literature (various boundary conditions, mesh sizes, and material properties) by using intraoperative imaging data (the public REtroSpective Evaluation of Cerebral Tumors [RESECT] database). Four patients with low-grade gliomas were identified as having inward brain-shifts. We computed the accuracy (using target registration error) of several FEM-based brain-shift predictions and compared our findings. Since information on head orientation during craniotomy is not included in this database, we tested various plausible angles of head rotation. We analyzed the effects of brain tissue viscoelastic properties, mesh size, craniotomy position, CSF drainage level, and rigidity of meninges and then quantitatively evaluated the trade-off between accuracy and central processing unit time in predicting inward brain-shift across all models with second-order tetrahedral FEMs. The mean initial target registration error (TRE) was 5.78 ± 3.78 mm with rigid registration. FEM prediction (edge-length, 5 mm) with non-rigid meninges led to a mean TRE correction of 1.84 ± 0.83 mm assuming heterogeneous material. Results show that, for the low-grade glioma patients in the study, including non-rigid modeling of the meninges was significant statistically. In contrast including heterogeneity was not significant. To estimate the optimal head orientation and CSF drainage, an angle step of 5° and an CSF height step of 5 mm were enough leading to <0.26 mm TRE fluctuation.

Proposed definition of competencies for surgical neuro-oncology training.

OBJECTIVE: The aim of this work is to define competencies and entrustable professional activities (EPAs) to be imparted within the framework of surgical neuro-oncological residency and fellowship training as well as the education of medical students. Improved and specific training in surgical neuro-oncology promotes neuro-oncological expertise, quality of surgical neuro-oncological treatment and may also contribute to further development of neuro-oncological techniques and treatment protocols. Specific curricula for a surgical neuro-oncologic education have not yet been established. METHODS: We used a consensus-building approach to propose skills, competencies and EPAs to be imparted within the framework of surgical neuro-oncological training. We developed competencies and EPAs suitable for training in surgical neuro-oncology. RESULT: In total, 70 competencies and 8 EPAs for training in surgical neuro-oncology were proposed. EPAs were defined for the management of the deteriorating patient, the management of patients with the diagnosis of a brain tumour, tumour-based resections, function-based surgical resections of brain tumours, the postoperative management of patients, the collaboration as a member of an interdisciplinary and/or -professional team and finally for the care of palliative and dying patients and their families. CONCLUSIONS AND RELEVANCE: The present work should subsequently initiate a discussion about the proposed competencies and EPAs and, together with the following discussion, contribute to the creation of new training concepts in surgical neuro-oncology.

Rate of incidental central nervous system meningioma detected in patients undergoing 18F-fluciclovine PET/CT imaging for evaluation of prostate cancer.

OBJECTIVE: To evaluate the rate of incidental detection of central nervous system (CNS) meningioma in patients undergoing 18F-fluciclovine PET/computed tomography (CT) imaging for the evaluation of prostate cancer. METHODS: The reports of 850 18F-fluciclovine PET/CT scans in 566 patients with pathologically proven prostate cancer performed from April 2017 to July 2019, were retrospectively reviewed for the presence of CNS meningioma. RESULTS: A total of 14 patients (2.8%) (age range: 54-82 years old) had abnormal focal intracranial 18F-fluciclovine uptake, all extra-axial in location (SUVmax range: 3.2-19.3). Two cases out of 14 (0.35%) were diagnosed as metastatic lesions. Twelve out of the 14 patients, had 18F-fluciclovine PET/CT imaging findings suspicious for CNS meningioma, 2 of them received another diagnosis on further imaging, and only 10 cases (2%) had the diagnosis of meningioma according to follow-up MRI and 18F-fluciclovine PET/CT. CONCLUSION: Focal 18F-fluciclovine avid intracranial lesions incidentally detected in patients undergoing PET/CT imaging for prostate cancer are most often CNS meningiomas.

Intraoperative MRI for Brain Tumors.

INTRODUCTION: The use of intraoperative imaging has been a critical tool in the neurosurgeon's armamentarium and is of particular benefit during tumor surgery. This article summarizes the history of its development, implementation, clinical experience and future directions. METHODS: We reviewed the literature focusing on the development and clinical experience with intraoperative MRI. Utilizing the authors' personal experience as well as evidence from the literature, we present an overview of the utility of MRI during neurosurgery. RESULTS: In the 1990s, the first description of using a low field MRI in the operating room was published describing the additional benefit provided by improved resolution of MRI as compared to ultrasound. Since then, implementation has varied in magnetic field strength and in configuration from floor mounted to ceiling mounted units as well as those that are accessible to the operating room for use during surgery and via an outpatient entrance to use for diagnostic imaging. The experience shows utility of this technique for increasing extent of resection for low and high grade tumors as well as preventing injury to important structures while incorporating techniques such as intraoperative monitoring. CONCLUSION: This article reviews the history of intraoperative MRI and presents a review of the literature revealing the successful implementation of this technology and benefits noted for the patient and the surgeon.

Challenges Associated with Reoperation in Patients with Glioma.

Reoperation for glioma is increasingly common but there is neither firm agreement on the indications nor unequivocally proven benefit from clinical trials. Patient and tumor factors should be considered when offering reoperation and a clear surgical goal set. Reoperation is challenging because of placement of previous incisions, wound devascularization by preceding radiotherapy and/or chemotherapy, chronic steroid use, the need for further adjuvant therapy, and adherent and defective dura. This article reviews indications, challenges, and recommendations for repeat surgery in the patient with glioma.