Spatial analysis of recurrent glioblastoma reveals perivascular niche organization.

Tumor evolution is driven by genetic variation; however, it is the tumor microenvironment (TME) that provides the selective pressure contributing to evolution in cancer. Despite high histopathological heterogeneity within glioblastoma (GBM), the most aggressive brain tumor, the interactions between the genetically distinct GBM cells and the surrounding TME are not fully understood. To address this, we analyzed matched primary and recurrent GBM archival tumor tissues with imaging-based techniques aimed to simultaneously evaluate tumor tissues for the presence of hypoxic, angiogenic, and inflammatory niches, extracellular matrix (ECM) organization, TERT promoter mutational status, and several oncogenic amplifications on the same slide and location. We found that the relationships between genetic and TME diversity are different in primary and matched recurrent tumors. Interestingly, the texture of the ECM, identified by label-free reflectance imaging, was predictive of single-cell genetic traits present in the tissue. Moreover, reflectance of ECM revealed structured organization of the perivascular niche in recurrent GBM, enriched in immunosuppressive macrophages. Single-cell spatial transcriptomics further confirmed the presence of the niche-specific macrophage populations and identified interactions between endothelial cells, perivascular fibroblasts, and immunosuppressive macrophages. Our results underscore the importance of GBM tissue organization in tumor evolution and highlight genetic and spatial dependencies.

Endoscope-assisted endonasal versus supraorbital keyhole resection of olfactory groove meningiomas: comparison and combination of 2 minimally invasive approaches.

OBJECTIVE: Although the endonasal endoscopic approach has been applied to remove olfactory groove meningiomas, controversy exists regarding the efficacy and safety of this approach compared with more traditional transcranial approaches. The endonasal endoscopic approach was compared with the supraorbital (eyebrow) keyhole technique, as well as a combined "above-and-below" approach, to evaluate the relative merits of each approach in different situations. METHODS: Nineteen cases were reviewed and divided according to operative technique into 3 different groups: purely endonasal (6 cases); supraorbital eyebrow (microscopic with endoscopic assistance; 7 cases); and combined endonasal endoscopic with either the bicoronal or eyebrow microscopic approach (6 cases). Resection was judged on postoperative MRI using volumetric analysis. Tumors were assessed based on the Mohr radiological classification and the presence of the lion's mane sign. RESULTS: The mean age at surgery was 61.4 years. The mean tumor volume was 19.6 cm(3) in the endonasal group, 33.5 cm(3) in the supraorbital group, and 37.8 cm(3) in the combined group. Significant frontal lobe edema was identified in 10 cases (52.6%). The majority of tumors were either Mohr Grade II (moderate) (42.1%) or Grade III (large) (47.4%). Gross-total resection was achieved in 50% of the endonasal cases, 100% of the supraorbital eyebrow cases with endoscopic assistance, and 66.7% of the combined cases. The extent of resection was 87.8% for the endonasal cases, 100% for the supraorbital eyebrow cases, and 98.9% for the combined cases. Postoperative anosmia occurred in 100% of the endonasal and combined cases and only 57.1% of the supraorbital eyebrow cases. Excluding anosmia, permanent complications occurred in 83.3% of the cases in the endoscopic group, 0% of the cases in the supraorbital eyebrow group, and 16.7% of cases in the combined group (p = 0.017). There were 3 tumor recurrences: 2 in the endonasal group and 1 in the combined group. CONCLUSIONS: The supraorbital eyebrow approach, with endoscopic assistance, leads to a higher extent of resection and lower rate of complications than the purely endonasal endoscopic approach. The endonasal endoscopic approach by itself may be suitable for a small percentage of cases. The combined above-and-below approaches are useful for large tumors with invasion of the ethmoid sinuses.

Endoscopic endonasal clip ligation of cerebral aneurysms: an anatomical feasibility study and future directions.

OBJECTIVE: The expansion of endovascular procedures for obliteration of cerebral aneurysms highlights one of the drawbacks of clip ligation through the transcranial route, namely brain retraction or brain transgression. Sporadic case reports have emerged over the past 10 years describing endonasal endoscopic clip ligation of cerebral aneurysms. The authors present a detailed anatomical study to evaluate the feasibility of an endoscopic endonasal approach for application of aneurysm clips. METHODS: Nine human cadaveric head specimens were used to evaluate operative exposures for clip ligation of aneurysms in feasible anterior and posterior circulation locations. Measurements of trajectories were completed using a navigation system to calculate skull base craniectomy size, corridor space, and the surgeon's ability to gain proximal and distal control of parent vessels. RESULTS: In each of the 9 cadaveric heads, excellent exposure of the target vessels was achieved. The transplanum, transtuberculum, and transcavernous approaches were used to explore the feasibility of anterior circulation access. Application of aneurysm clips was readily possible to the ophthalmic artery, A1 and A2 segments of the anterior cerebral artery, anterior communicating artery complex, and the paraclinoid and paraclival internal carotid artery. The transclival approach was explored, and clips were successfully deployed along the proximal branches of the vertebrobasilar system and basilar trunk and bifurcation. The median sizes of skull base craniectomy necessary for exposure of the anterior communicating artery complex and basilar tip were 3.24 cm(2) and 4.62 cm(2), respectively. The mean angles of surgical corridors to the anterior communicating artery complex and basilar tip were 11.4° and 14°, respectively. Although clip placement was feasible on the basilar artery and its branches, the associated perforating arteries were difficult to visualize, posing unexpected difficulty for safe clip application, with the exception of ventrolateral-pointing aneurysms. CONCLUSIONS: The authors characterize the feasibility of endonasal endoscopic clip ligation of aneurysms involving the paraclinoid, anterior communicating, and basilar arteries and proximal control of the paraclival internal carotid artery. The endoscopic approach should be initially considered for nonruptured aneurysms involving the paraclinoid and anterior communicating arteries, as well as ventrolateral basilar trunk aneurysms. Clinical experience will be mandatory to determine the applicability of this approach in practice.

Pneumocephalus patterns following endonasal endoscopic skull base surgery as predictors of postoperative CSF leaks.

OBJECTIVES: Postoperative pneumocephalus is a common occurrence after endoscopic endonasal skull base surgery (ESBS). The risk of cerebrospinal fluid (CSF) leaks can be high and the presence of postoperative pneumocephalus associated with serosanguineous nasal drainage may raise suspicion for a CSF leak. The authors hypothesized that specific patterns of pneumocephalus on postoperative imaging could be predictive of CSF leaks. Identification of these patterns could guide the postoperative management of patients undergoing ESBS. METHODS: The authors queried a prospectively acquired database of 526 consecutive ESBS cases at a single center between December 1, 2003, and May 31, 2012, and identified 258 patients with an intraoperative CSF leak documented using intrathecal fluorescein. Postoperative CT and MRI scans obtained within 1-10 days were examined and pneumocephalus was graded based on location and amount. A discrete 0-4 scale was used to classify pneumocephalus patterns based on size and morphology. Pneumocephalus was correlated with the surgical approach, histopathological diagnosis, and presence of a postoperative CSF leak. RESULTS: The mean follow-up duration was 56.7 months. Of the 258 patients, 102 (39.5%) demonstrated pneumocephalus on postoperative imaging. The most frequent location of pneumocephalus was frontal (73 [71.5%] of 102), intraventricular (34 [33.3%]), and convexity (22 [21.6%]). Patients with craniopharyngioma (27 [87%] of 31) and meningioma (23 [68%] of 34) had the highest incidence of postoperative pneumocephalus compared with patients with pituitary adenomas (29 [20.6%] of 141) (p < 0.0001). The incidence of pneumocephalus was higher with transcribriform and transethmoidal approaches (8 of [73%] 11) than with a transsellar approach (9 of [7%] 131). There were 15 (5.8%) of 258 cases of postoperative CSF leak, of which 10 (66.7%) had pneumocephalus, compared with 92 (38%) of 243 patients without a postoperative CSF leak (OR 3.3, p = 0.027). Pneumocephalus located in the convexity, interhemispheric fissure, sellar region, parasellar region, and perimesencephalic region was significantly correlated with a postoperative CSF leak (OR 4.9, p = 0.006) and was therefore termed "suspicious" pneumocephalus. In contrast, frontal or intraventricular pneumocephalus was not correlated with postoperative CSF leak (not significant) and was defined as "benign" pneumocephalus. The amount of convexity pneumocephalus (p = 0.002), interhemispheric pneumocephalus (p = 0.005), and parasellar pneumocephalus (p = 0.007) (determined using a scale score of 0-4) was also significantly related to postoperative CSF leaks. Using a series of permutation-based multivariate analyses, the authors established that a model containing the learning curve, the transclival/transcavernous approach, and the presence of "suspicious" pneumocephalus provides the best overall prediction for postoperative CSF leaks. CONCLUSIONS: Postoperative pneumocephalus is much more common following extended approaches than following transsellar surgery. Merely the presence of pneumocephalus, particularly in the frontal or intraventricular locations, is not necessarily associated with a postoperative CSF leak. A "suspicious" pattern of air, namely pneumocephalus in the convexity, interhemispheric fissure, sella, parasellar, or perimesencephalic locations, is significantly associated with a postoperative CSF leak. The presence and the score of "suspicious" pneumocephalus on postoperative imaging, in conjunction with the learning curve and the type of endoscopic approach, provide the best predictive model for postoperative CSF leaks.

The transplanum transtuberculum approaches for suprasellar and sellar-suprasellar lesions: avoidance of cerebrospinal fluid leak and lessons learned.

OBJECTIVE: To present a large series of patients and examine the learning curve of the endonasal endoscopic transplanum, transtuberculum approach for primarily suprasellar or sellar-suprasellar tumors. METHODS: We identified 122 patients who underwent 126 surgeries using the transplanum, transtuberculum approach. Extent of resection was determined with volumetric analysis of magnetic resonance imagings. Results concerning vision, endocrine function, and complications were noted. RESULTS: Average tumor volume was 14 cm(3). The most frequent pathologies were pituitary macroadenoma (51.6%), craniopharyngioma (20.6%), and meningioma (15.9%). A total of 73% patients presented with visual compromise. Rates of gross total resection (GTR) and near total resection for the group as a whole were 58.1% and 13.7%, and for the patients in whom GTR was intended (n = 90), rates of GTR and near total resection were 77.5% and 12.5% for a total of 90%. Extent of resection in this group was 97.6%. Vision improved in 52.4% and deteriorated in 4.8%. Favorable endocrine outcome occurred in 63.5%. The cerebrospinal fluid leak rate was 3.1% for the series as a whole. It improved from 6.3% in the first half of the series to 0 in the second half. Leak rates varied with technique from 11% (fat graft only) to 4.2% (gasket seal only) to 1.8% (fat plus nasoseptal flap) to 0 (gasket plus nasoseptal flap). The rate of other complications was 14.3% in the first half of the series and 1.6% in the second half. There was one infection (0.8%). CONCLUSIONS: The endonasal endoscopic transtuberculum transplanum approach is a safe and effective minimal access approach to midline pathology in the suprasellar cistern.

Case-specific protocol to reduce cerebrospinal fluid leakage after endonasal endoscopic surgery.

OBJECT: Endoscopic transsphenoidal surgery is expanding in acceptance, yet postoperative CSF leak rates remain a concern. This study presents the Cornell closure protocol, which has yielded significantly lower postoperative CSF leak rates compared with prior reports, as an algorithm that can be used by centers having difficulty with CSF leak. METHODS: A single closure algorithm for endoscopic surgery has been used since January 2010 at Weill Cornell Medical College. A prospective database noting intraoperative CSF leak, closure technique, and postoperative CSF leak was reviewed. The authors used a MEDLINE search to identify similar studies and compared CSF leak rates to those of patients treated using the Cornell algorithm. RESULTS: The retrospective study of a prospectively acquired database included 209 consecutive patients. In 84 patients (40%) there was no intraoperative CSF leak and no postoperative CSF leak. In the 125 patients (60%) with an intraoperative CSF leak, 35 of them with high-flow leaks, there were 0 (0%) postoperative CSF leaks. CONCLUSIONS: It is possible to achieve a CSF leak rate of 0% by using this closure protocol. With proper experience, endoscopic skull base surgery should not be considered to have a higher CSF leak rate than open transcranial or microscopic transsphenoidal surgery.

Cranioplasty after postinjury decompressive craniectomy: is timing of the essence?

BACKGROUND: The appropriate timing of cranioplasty after decompressive craniectomy for trauma is unknown. Potential benefits of delayed intervention (>6 weeks) for reducing the risk of infection must be balanced by persistent altered cerebrospinal fluid dynamics leading to hydrocephalus. We reviewed our recent 5-year experience in an effort to improve patient throughput and develop a rational decision making plan. METHODS: A 5-year query (2003-2007) of our level I neurotrauma database. From 2,400 head injuries, we performed a total of 350 craniotomies. Of the 350 patients who underwent craniotomy for trauma, 70 patients (20%) underwent decompressive craniectomy requiring cranioplasty. Timing of cranioplasty, cranioplasty material, postoperative infections, and incidence of hydrocephalus were evaluated with logistic regression to study potential associations between complications and timing, adjusted for risk factors. RESULTS: No specific time frame was predictive of hydrocephalus or infection, and logistic regression failed to identify significant predictors among the collected variables. CONCLUSION: In our experience, the prior practice of delayed cranioplasty (3-6 months postdecompressive craniectomy), requiring repeat hospital admission, does not seem to lower postcranioplasty infection rates nor the need for cerebrospinal fluid diversion procedures. Our current practice emphasizes cranioplasty during the initial hospital admission, as soon as there is resolution on computed tomography scan of brain swelling outside of the cranial vault with concurrent clinical examination. This occurs as early as 2 weeks postcraniectomy and should lower the overall cost of care by eliminating the need for additional hospital admissions.

Genetically engineered T cells to target EGFRvIII expressing glioblastoma.

Glioblastoma remains a significant therapeutic challenge, warranting further investigation of novel therapies. We describe an immunotherapeutic strategy to treat glioblastoma based on adoptive transfer of genetically modified T-lymphocytes (T cells) redirected to kill EGFRvIII expressing gliomas. We constructed a chimeric immune receptor (CIR) specific to EGFRvIII, (MR1-zeta). After in vitro selection and expansion, MR1-zeta genetically modified primary human T-cells specifically recognized EGFRvIII-positive tumor cells as demonstrated by IFN-gamma secretion and efficient tumor lysis compared to control CIRs defective in EGFRvIII binding (MRB-zeta) or signaling (MR1-delzeta). MR1-zeta expressing T cells also inhibited EGFRvIII-positive tumor growth in vivo in a xenografted mouse model. Successful targeting of EGFRvIII-positive tumors via adoptive transfer of genetically modified T cells may represent a new immunotherapy strategy with great potential for clinical applications.

Traumatic unilateral lumbosacral jumped facet without fracture in a child - presentation of a safe treatment strategy for a rare injury.

The vast majority of pediatric lumbosacral spondylolisthesis have developmental etiology. Of the very rare type of pediatric lumbosacral facet dislocations, there are only three reported cases of a pediatric unilateral jumped facet injury. All of these cases are associated with fracture dislocation of L5-S1. Hyperflexion with rotation is thought to provoke this uncommon type of spine injury.The authors report the first pediatric patient reported in literature to date with a traumatic unilateral jumped facet at the lumbosacral joint without fracture. The presentation, surgical treatment, hospital course, outcome and management options with the review of the literature is summarized.

Genetic and cellular therapies for cerebral infarction.

Neurosurgeons, working as surgical scientists, can have a prominent role in developing and implementing genetic and cellular therapies for cerebral ischemia. The rapid emergence of both genetic and cellular therapies for neural regeneration warrants a careful analysis before implementation of human studies to understand the pitfalls and promises of this strategy. In this article, we review the topic of genetic and cellular therapy for stroke to provide a foundation for practicing neurosurgeons and clinical scientists who may become involved in this type of work. In Part 1, we review preclinical approaches with gene transfer, such as 1) improved energy delivery, 2) reduction of intracellular calcium availability, 3) abrogation of effects of reactive oxygen species, 4) reduction of proinflammatory cytokine signaling, 5) inhibition of apoptosis mediators, and 6) restorative gene therapy, that are paving the way to develop new strategies to treat cerebral infarction. In Part 2, we discuss the results of studies that address the possibility of using cellular therapies for stroke in animal models and in human trials by reviewing 1) the basics of stem cell biology, 2) exogenous and 3) and endogenous cell sources for therapy, and 4) clinical considerations in cell therapy applications. These emerging technologies based on the advancements made in recent years in the fields of genetics, therapeutic cloning, neuroscience, stem cell biology, and gene therapy provide significant potential for new therapies for stroke.

Successful inhibition of intracranial human glioblastoma multiforme xenograft growth via systemic adenoviral delivery of soluble endostatin and soluble vascular endothelial growth factor receptor-2: laboratory investigation.

OBJECT: Glioblastoma multiforme (GBM) is characterized by neovascularization, raising the question of whether angiogenic blockade may be a useful therapeutic strategy for this disease. It has been suggested, however, that, to be useful, angiogenic blockade must be persistent and at levels sufficient to overcome proangiogenic signals from tumor cells. In this report, the authors tested the hypothesis that sustained high concentrations of 2 different antiangiogenic proteins, delivered using a systemic gene therapy strategy, could inhibit the growth of established intracranial U87 human GBM xenografts in nude mice. METHODS: Mice harboring established U87 intracranial tumors received intravenous injections of adenoviral vectors encoding either the extracellular domain of vascular endothelial growth factor receptor-2-Fc fusion protein (Ad-VEGFR2-Fc) alone, soluble endostatin (Ad-ES) alone, a combination of Ad-VEGFR2-Fc and Ad-ES, or immunoglobulin 1-Fc (Ad-Fc) as a control. RESULTS: Three weeks after treatment, magnetic resonance imaging-based determination of tumor volume showed that treatment with Ad-VEGFR2-Fc, Ad-ES, or Ad-VEGFR2-Fc in combination with Ad-ES, produced 69, 59, and 74% growth inhibition, respectively. Bioluminescent monitoring of tumor growth revealed growth inhibition in the same treatment groups to be 62, 74, and 72%, respectively. Staining with proliferating cell nuclear antigen and with terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling showed reduced tumor cell proliferation and increased apoptosis in all antiangiogenic treatment groups. CONCLUSIONS: These results suggest that systemic delivery and sustained production of endostatin and soluble VEGFR2 can slow intracranial glial tumor growth by both reducing cell proliferation and increasing tumor apoptosis. This work adds further support to the concept of using antiangiogenesis therapy for intracranial GBM.

Noninvasive bioluminescence imaging of luciferase expressing intracranial U87 xenografts: correlation with magnetic resonance imaging determined tumor volume and longitudinal use in assessing tumor growth and antiangiogenic treatment effect.

OBJECTIVE: Outcome studies in rodent tumor models rely on both histological and noninvasive study end points. Intracranial models require special tools to observe tumor growth over time noninvasively, such as magnetic resonance imaging (MRI), computed tomographic scanning, or cranial window techniques. These techniques share disadvantages in terms of cost, technical expertise required, and overall animal throughput for analysis. In this report, we sought to validate the use of the relatively newer technique of bioluminescence imaging (BLI) of intracranial glioblastoma xenograft growth by comparing it with gadolinium-enhanced MRI. METHODS: U87MG glioma cell lines genetically engineered to express the firefly luciferase gene were stereotactically injected into nude mice in the left frontal lobe. Weekly BLI and MRI were performed after the inoculation of tumor cells. For BLI, tumor growth was assessed as the peak BLI after systemic injection of luciferin substrate. MRI-based growth curves were created by three-dimensional volumetric reconstruction of axial gadolinium-enhanced MRI data covering the whole brain. In a separate experiment, mice were treated with adenoviruses encoding antiangiogenic soluble vascular endothelial growth factor receptors, and treatment effect was monitored by BLI. RESULTS: Untreated tumor growth was readily detected and observed over time by serial BLI measurements. Furthermore, tumor-derived light emission was highly correlated with volume of tumor as assessed by MRI. Furthermore, the tested antiangiogenic treatment effect was readily detected using this technique, suggesting the power of the technique for sensitive monitoring of novel therapeutics. CONCLUSION: BLI offers a simple and rapid technique for assessing intracranial glioblastoma growth in rodent models noninvasively, which correlates well with MRI. The speed of the BLI technique can increase experimental throughput, allows for targeted histological analysis in animals showing the greatest treatment effects, and provides new insights into the kinetics of intracranial tumor growth in the setting of different treatments.

Adult-born and preexisting olfactory granule neurons undergo distinct experience-dependent modifications of their olfactory responses in vivo.

Neurogenesis continues throughout adulthood in the mammalian olfactory bulb and hippocampal dentate gyrus, suggesting the hypothesis that recently generated, adult-born neurons contribute to neural plasticity and learning. To explore this hypothesis, we examined whether olfactory experience modifies the responses of adult-born neurons to odorants, using immediate early genes (IEGs) to assay the response of olfactory granule neurons. We find that, shortly after they differentiate and synaptically integrate, the population of adult-born olfactory granule neurons has a greater population IEG response to novel odors than mature, preexisting neurons. Familiarizing mice with test odors increases the response of the recently incorporated adult-born neuron population to the test odors, and this increased responsiveness is long lasting, demonstrating that the response of the adult-born neuron population is altered by experience. In contrast, familiarizing mice with test odors decreases the IEG response of developmentally generated neurons, suggesting that recently generated adult-born neurons play a distinct role in olfactory processing. The increased IEG response is stimulus specific; familiarizing mice with a set of different, "distractor" odors does not increase the adult-born neuron population response to the test odors. Odor familiarization does not influence the survival of adult-born neurons, indicating that the changes in the population response of adult-born neurons are not attributable to increased survival of odor-stimulated neurons. These results demonstrate that recently generated adult-born olfactory granule neurons and older, preexisting granule neurons undergo contrasting experience-dependent modifications in vivo and support the hypothesis that adult-born neurons are involved in olfactory learning.

Genetic and cellular therapies for cerebral infarction.

Neurosurgeons, working as surgical scientists, can have a prominent role in developing and implementing genetic and cellular therapies for cerebral ischemia. The rapid emergence of both genetic and cellular therapies for neural regeneration warrants a careful analysis before implementation of human studies to understand the pitfalls and promises of this strategy. In this article, we review the topic of genetic and cellular therapy for stroke to provide a foundation for practicing neurosurgeons and clinical scientists who may become involved in this type of work. In Part 1, we review preclinical approaches with gene transfer, such as 1) improved energy delivery, 2) reduction of intracellular calcium availability, 3) abrogation of effects of reactive oxygen species, 4) reduction of proinflammatory cytokine signaling, 5) inhibition of apoptosis mediators, and 6) restorative gene therapy, that are paving the way to develop new strategies to treat cerebral infarction. In Part 2, we discuss the results of studies that address the possibility of using cellular therapies for stroke in animal models and in human trials by reviewing 1) the basics of stem cell biology, 2) exogenous and 3) and endogenous cell sources for therapy, and 4) clinical considerations in cell therapy applications. These emerging technologies based on the advancements made in recent years in the fields of genetics, therapeutic cloning, neuroscience, stem cell biology, and gene therapy provide significant potential for new therapies for stroke.