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Statistically and clinically significant cognitive declines are observed in a small subset of individuals with Parkinson's Disease (PD) following treatment with Deep Brain Stimulation (DBS).We examine the association between multi-domain cognitive decline (MCD) and demographic and baseline clinical variables and the incidence of serious adverse events (SAE) arising within a six-month interval following DBS for PD.Study participants with PD who displayed MCD at 6-month follow-up evaluation after DBS (n = 18) were contrasted with individuals with PD from the same study who did not show cognitive decline after DBS (n = 146). Logistic regression analyses were employed to assess relationship between predictors, including age (70 years old), pre-DBS cognitive screening test performance, SAE, and MCD. MCD+ and MCD-groups were also compared on other baseline clinical and demographic variables.MCD showed modest association with older age and lower baseline neurocognitive screening performance, whereas the groups did not differ on most other baseline clinical and demographic variables. SAEs during the study interval were the most robust predictor of MCD in the DBS group. A variety of SAEs were documented in study participants experiencing MCD after DBS surgery, including, but not limited to, infections and small intracranial hemorrhages.Older age and lower baseline cognition measured prior to treatment are associated with MCD measured at six-months after DBS. SAE occurring following DBS surgery are also predictive of MCD. These predictors may reflect aspects of "frailty" in advanced PD. Risk factors for SAE warrant careful consideration in clinical trials.

The purpose of this report is to chronicle a 2-decade period of educational innovation and improvement, as well as governance reform, across the specialty of neurological surgery. Neurological surgery educational and professional governance systems have evolved substantially over the past 2 decades with the goal of improving training outcomes, patient safety, and the quality of US neurosurgical care. Innovations during this period have included the following: creating a consensus national curriculum; standardizing the length and structure of neurosurgical training; introducing educational outcomes milestones and required case minimums; establishing national skills, safety, and professionalism courses; systematically accrediting subspecialty fellowships; expanding professional development for educators; promoting training in research; and coordinating policy and strategy through the cooperation of national stakeholder organizations. A series of education summits held between 2007 and 2009 restructured some aspects of neurosurgical residency training. Since 2010, ongoing meetings of the One Neurosurgery Summit have provided strategic coordination for specialty definition, neurosurgical education, public policy, and governance. The Summit now includes leadership representatives from the Society of Neurological Surgeons, the American Association of Neurological Surgeons, the Congress of Neurological Surgeons, the American Board of Neurological Surgery, the Review Committee for Neurological Surgery of the Accreditation Council for Graduate Medical Education, the American Academy of Neurological Surgery, and the AANS/CNS Joint Washington Committee. Together, these organizations have increased the effectiveness and efficiency of the specialty of neurosurgery in advancing educational best practices, aligning policymaking, and coordinating strategic planning in order to meet the highest standards of professionalism and promote public health.

Molecular classification has transformed the management of brain tumors by enabling more accurate prognostication and personalized treatment. However, timely molecular diagnostic testing for patients with brain tumors is limited, complicating surgical and adjuvant treatment and obstructing clinical trial enrollment. In this study, we developed DeepGlioma, a rapid ($< 90$ seconds), artificial-intelligence-based diagnostic screening system to streamline the molecular diagnosis of diffuse gliomas. DeepGlioma is trained using a multimodal dataset that includes stimulated Raman histology (SRH); a rapid, label-free, non-consumptive, optical imaging method; and large-scale, public genomic data. In a prospective, multicenter, international testing cohort of patients with diffuse glioma ($n=153$) who underwent real-time SRH imaging, we demonstrate that DeepGlioma can predict the molecular alterations used by the World Health Organization to define the adult-type diffuse glioma taxonomy (IDH mutation, 1p19q co-deletion and ATRX mutation), achieving a mean molecular classification accuracy of $93.3\pm 1.6\%$. Our results represent how artificial intelligence and optical histology can be used to provide a rapid and scalable adjunct to wet lab methods for the molecular screening of patients with diffuse glioma., Paper published in Nature Medicine

BACKGROUNDHigh-grade gliomas are fatal with universally poor prognosis. Initiation of effective cancer immune responses requires functional immune cells, especially afferent antigen presenting cells, which are absent from the brain parenchyma.1, 2To address this requirement, two adenoviral vectors expressing HSV1-TK and Flt3L were combined to target human gliomas. This first in human trial assessed safety, cytotoxicity, and immune recruitment to the tumor.METHODSEighteen treatment-naïve adults with high-grade glioma received injections of HSV1-TK- and Flt3L-expressing adenoviral vectors to the tumor bed after maximal safe resection, at six escalating doses (total 1.1×1010-2×1011vp), followed by two 14-day courses of valacyclovir, and standard upfront chemoradiation. Key inclusion criteria were: age 18-75, KPS ≥70, and treatment-naïve high-grade glioma amenable to gross total resection. Patients were consented pre-operatively. Enrollment occurred intraoperatively, upon pathology confirmation.RESULTSThe treatment was well tolerated without dose-limiting toxicity in patients with glioblastoma (n=17) (3 of the gliosarcoma variant), or anaplastic ependymoma (n=1). The maximal-tolerated dose was not reached. The median overall-survival was 21.3 months (95%CI: 11.1, 26.1). Tissues from subsequent resections from 8 subjects showed elevated markers for CD3+ and CD8+ T cells indicating potential successful anti-glioma immunity recruitment. Multiplex immunohistochemistry on two patients indicated a change in the intratumoral redistribution of CD8+ T cells and microglia/macrophages.CONCLUSIONSUse of two adenoviral vectors expressing HSV1-TK and Flt3L is safe and well tolerated in newly diagnosed high-grade glioma patients. Promising multiplex immunocytochemical evidence of immune infiltration warrants further efficacy studies, possibly in combination with blockade of the inhibitory tumor microenvironment.(Funded in part by Phase One Foundation, Los Angeles, CA, The Board of Governors at Cedars-Sinai Medical Center, and The Rogel Cancer Center at The University of Michigan; clinicaltrials.gov:NCT01811992)

Molecular classification has transformed the management of brain tumors by enabling more accurate prognostication and personalized treatment. However, timely molecular diagnostic testing for brain tumor patients is limited [1–3], complicating surgical and adjuvant treatment and obstructing clinical trial enrollment [4]. Here, we developed DeepGlioma, a rapid (

AimsTargeting tumor metabolism may improve the outcomes for patients with glioblastoma (GBM). To further preclinical efforts targeting metabolism in GBM, we tested the hypothesis that brain tumors can be stratified into distinct metabolic groups with different patient outcomes. Therefore, to determine if tumor metabolites relate to patient survival, we profiled the metabolomes of human gliomas and correlated metabolic information with clinical data.ResultsWe found that isocitrate dehydrogenase-wildtype (IDHwt) GBMs are metabolically distinguishable from IDH mutated (IDHmut) astrocytomas and oligodendrogliomas. Survival of patients with IDHmut gliomas was expectedly more favorable than those with IDHwt GBM, and metabolic signatures can stratify IDHwt GBMs subtypes with varying prognoses. Patients whose GBMs were enriched in amino acids had improved survival while those whose tumors were enriched for nucleobases and carbohydrates fared more poorly. These findings were recapitulated in validation cohorts using both metabolomic and transcriptomic data.InnovationOur results suggest the existence of metabolic subtypes of GBM with differing prognoses and further support the concept that metabolism may drive the aggressiveness of human gliomas.ConclusionsOur data show that metabolic signatures of human gliomas can inform patient survival. These findings may be used clinically to tailor novel metabolically targeted agents for GBM patients with different metabolic phenotypes.

Background Detection of glioma recurrence remains a challenge in modern neuro-oncology. Noninvasive radiographic imaging is unable to definitively differentiate true recurrence versus pseudoprogression. Even in biopsied tissue, it can be challenging to differentiate recurrent tumor and treatment effect. We hypothesized that intraoperative stimulated Raman histology (SRH) and deep neural networks can be used to improve the intraoperative detection of glioma recurrence. Methods We used fiber laser–based SRH, a label-free, nonconsumptive, high-resolution microscopy method ( Results Using patch-level CNN predictions, the inference algorithm returns a single Bernoulli distribution for the probability of tumor recurrence for each surgical specimen or patient. The external SRH validation dataset consisted of 48 patients (recurrent, 30; pseudoprogression, 18), and we achieved a diagnostic accuracy of 95.8%. Conclusion SRH with CNN-based diagnosis can be used to improve the intraoperative detection of glioma recurrence in near-real time. Our results provide insight into how optical imaging and computer vision can be combined to augment conventional diagnostic methods and improve the quality of specimen sampling at glioma recurrence.

Intraoperative diagnosis is essential for providing safe and effective care during cancer surgery1. The existing workflow for intraoperative diagnosis based on hematoxylin and eosin staining of processed tissue is time, resource and labor intensive2,3. Moreover, interpretation of intraoperative histologic images is dependent on a contracting, unevenly distributed, pathology workforce4. In the present study, we report a parallel workflow that combines stimulated Raman histology (SRH)5-7, a label-free optical imaging method and deep convolutional neural networks (CNNs) to predict diagnosis at the bedside in near real-time in an automated fashion. Specifically, our CNNs, trained on over 2.5 million SRH images, predict brain tumor diagnosis in the operating room in under 150 s, an order of magnitude faster than conventional techniques (for example, 20-30 min)2. In a multicenter, prospective clinical trial (n = 278), we demonstrated that CNN-based diagnosis of SRH images was noninferior to pathologist-based interpretation of conventional histologic images (overall accuracy, 94.6% versus 93.9%). Our CNNs learned a hierarchy of recognizable histologic feature representations to classify the major histopathologic classes of brain tumors. In addition, we implemented a semantic segmentation method to identify tumor-infiltrated diagnostic regions within SRH images. These results demonstrate how intraoperative cancer diagnosis can be streamlined, creating a complementary pathway for tissue diagnosis that is independent of a traditional pathology laboratory.

BACKGROUND De novo purine synthesis promotes glioblastoma growth and stemness, invasiveness, and resistance to chemoradiation. Mycophenolate mofetil (MMF) is an FDA-approved inhibitor of de novo purine synthesis that sensitizes glioblastoma to radiation and chemotherapy in mice. This Phase 0/I trial of MMF with Radiotherapy in Recurrent Glioblastoma (NCT04477200) aims to determine the maximum-tolerated dose of MMF that can be combined with radiation,and the extent to which the active metabolite of MMF accumulates in brain tumors and inhibits de novo purine synthesis. METHODS Key eligibility criteria are age ≥18, KPS score ≥60%, and recurrent glioblastoma or gliosarcoma with clinical indication for re-irradiation (phase I) or re-resection/biopsy (phase 0). Patients with tumors involving ≥3 lobes or leptomeningeal space or bevacizumab use within 8 weeks are excluded. MMF 500-2000mg PO BID is given one week pre-operatively in Phase 0 (N=8), and up to 2000mg PO BID (starting 1000mg) on TITE-CRM dose escalation on Phase 1 cohort (N=30). RESULTS Since 7/2020, three Phase 0 and six Phase I subjects have been enrolled. On the phase I cohort, 1500mg BID dose has been reached. Studyrelated toxicities have been limited to mainly grade 1-2 nausea and fatigue. No notable study related hematotoxicity have been noted. Additionally, mass spectrometry-based correlative measurements of the activity of de novo GTP synthesis are ongoing. CONCLUSION MMF has been well tolerated up to 1500mg BID combined with radiotherapy in recurrent glioblastoma patients in this interim analysis. An additional upfront glioblastoma cohort with MMF with standard of care will activate in 2021. These studies will determine the maximum tolerated dose of MMF in combination with radiation and chemotherapy and provide a preliminary efficacy estimate at that dose. Encouraging results would support a randomized clinical trial to determine efficacy of MMF combined with chemoradiation in glioblastoma, and to define potential biomarkers for effectiveness.

BACKGROUND Purine metabolism promotes glioblastoma growth, stemness, invasiveness, and treatment resistance. The purine synthesis inhibitor, mycophenolate mofetil (MMF), improves radiation and temozolomide efficacy in preclinical glioblastoma models. This phase 0/1 trial (NCT04477200) aims to determine the maximum-tolerated dose of MMF combined with chemoradiation in glioblastoma. It also aims to quantify the levels of the active metabolite of MMF and the extent of purine synthesis inhibition in enhancing and non-enhancing tumor tissue. METHODS Key eligibility criteria are age ≥ 18 and KPS ≥ 60%. TITE-CRM dose-escalation is used for MMF dosing starting at 1000mg PO BID (range 500-2000mg BID). Thirty recurrent glioblastoma patients receive MMF one-week prior to and concurrently with re-irradiation (40.5 Gy in 15 fractions), with 28 days of dose-limiting toxicity (DLT) period. Thirty newly diagnosed glioblastoma patients receive MMF one-week prior to and concurrently with standard radiation with concurrent temozolomide and followed for 28 days for DLT1-period, then MMF is given days 0-5 of each adjuvant cyclic temozolomide using a separate dose-escalation with the first two cycles as the DLT2-period. In phase 0, eight recurrent glioblastoma patients receive MMF 500-2000mg PO BID one-week pre-operatively and tissues are analyzed using mass spectrometry. RESULTS Eighteen phase 1 subjects (11 recurrent, 7 new) have received study treatment with no DLT to date up to MMF 2000mg BID. Main toxicities are mild nausea, fatigue, and elevated liver enzymes. No notable study-related hematotoxicity nor opportunistic infection have been observed. The active metabolite of MMF accumulated to active concentrations in enhancing and non-enhancing tumor tissue and appeared to inhibit purine synthesis. CONCLUSION MMF combined with chemoradiation has been reasonably well tolerated in glioblastoma patients with preliminary evidence of intracranial target engagement of its active metabolite. This study will yield a recommended phase 2 dose and preliminary efficacy estimate for future randomized phase 2/3 trial.

PurposeGlioblastoma (GBM) is a lethal disease characterized by inevitable recurrence. Here we investigate the molecular pathways mediating resistance, with the goal of identifying therapeutic opportunities to target this tumor.Experimental DesignWe developed a longitudinal in vivo recurrence model utilizing patient-derived explants to produce paired specimens (pre- and post-recurrence) following temozolomide(TMZ) and radiation(IR). These specimens were evaluated for treatment response and to identify gene expression pathways driving treatment resistance. Findings were clinically validated using spatial transcriptomics of human GBMs.ResultsThese studies reveal in replicate cohorts, a gene expression profile characterized by upregulation of mesenchymal and stem-like genes at recurrence. Analyses of clinical databases revealed increased expression of this transcriptional profile to be significantly associated with worse median overall survival (248 days vs 430 days, p=0.0004), and upregulation of this profile at recurrence. Most notably, we identified upregulation of TGFβ signaling, and more than one-hundred-fold increase in THY1 levels at recurrence. Utilizing cell sorting, we observed that THY1-positive cells represented THY1+ regions characterized by mesenchymal/stem-like gene expression, analogous to our recurrent mouse model samples, which co-localized with macrophages within the perivascular niche. Since TGFβ signaling contributes to a mesenchymal/stem-like phenotype, we inhibited TGFβRI activity in vivo which resulted in decreased mesenchymal/stem-like protein levels, including THY1, and restored sensitivity to TMZ/IR in recurrent tumors.ConclusionsThese findings reveal that GBM recurrence may result from tumor repopulation by pre-existing, therapy-resistant, THY1-positive, mesenchymal/stem-like cells within the perivascular niche. Furthermore, our data demonstrate the promise of targeting upregulated pathways in resistant subclones as a novel mechanism to achieve therapeutic response, and specifically that THY1 expression may represent a biomarker of response to TGFβ inhibition.

Purpose: Glioblastoma (GBM) is a lethal disease characterized by inevitable recurrence. Here we investigate the molecular pathways mediating resistance, with the goal of identifying therapeutic opportunities to target this tumor. Experimental Design: We developed a longitudinal in vivo recurrence model utilizing patient-derived explants to produce paired specimens (pre- and post-recurrence) following temozolomide(TMZ) and radiation(IR). These specimens were evaluated for treatment response and to identify gene expression pathways driving treatment resistance. Findings were clinically validated using spatial transcriptomics of human GBMs. Results: These studies reveal in replicate cohorts, a gene expression profile characterized by upregulation of mesenchymal and stem-like genes at recurrence. Analyses of clinical databases revealed increased expression of this transcriptional profile to be significantly associated with worse median overall survival (248 days vs 430 days, p=0.0004), and upregulation of this profile at recurrence. Most notably, we identified upregulation of TGFβ signaling, and more than one-hundred-fold increase in THY1 levels at recurrence. Utilizing cell sorting, we observed that THY1-positive cells represented Conclusions: These findings reveal that GBM recurrence may result from tumor repopulation by pre-existing, therapy-resistant, THY1-positive, mesenchymal/stem-like cells within the perivascular niche. Furthermore, our data demonstrate the promise of targeting upregulated pathways in resistant subclones as a novel mechanism to achieve therapeutic response, and specifically that THY1 expression may represent a biomarker of response to TGFβ inhibition. Citation Format: Wajd N. Al-Holou, Hanxiao Wang, Visweswaran Ravikumar, Morgan Oneka, Roel G. Verhaak, Hoon Kim, Drew Pratt, Sandra Camelo-Piragua, Corey Speers, Daniel Wahl, Sunita Shankar, Todd Hollon, Oren Sagher, Jason Heth, Karin M. Muraszko, Theodore S. Lawrence, Ana C. deCarvalho, Tom Mikkelsen, Arvind Rao, Alnawaz Rehemtulla. Subclonal evolution and expansion of spatially distinct THY1-positive cells is associated with recurrence in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB013.

The rate of interictal high frequency oscillations (HFOs) is a promising biomarker of the seizure onset zone, though little is known about its consistency over hours to days. Here we test whether the highest HFO-rate channels are consistent across different 10-min segments of EEG during sleep. An automated HFO detector and blind source separation are applied to nearly 3000 total hours of data from 121 subjects, including 12 control subjects without epilepsy. Although interictal HFOs are significantly correlated with the seizure onset zone, the precise localization is consistent in only 22% of patients. The remaining patients either have one intermittent source (16%), different sources varying over time (45%), or insufficient HFOs (17%). Multiple HFO networks are found in patients with both one and multiple seizure foci. These results indicate that robust HFO interpretation requires prolonged analysis in context with other clinical data, rather than isolated review of short data segments., High frequency oscillations (HFO) are a promising biomarker for identifying epileptogenic zones without the need to monitor spontaneous seizure episodes. Here the authors report that there is much variability in the location of HFOs offering a note of caution toward using HFO locations from short recordings as a guide for surgery.

This is an interim report on a first in human Phase I dose escalation trial of the combination of two adenoviral vectors expressing HSV1-TK or Flt3L for the treatment of newly diagnosed, resectable malignant gliomas. Lack of dendritic cells from the brain precludes anti-glioma immune responses. We combined tumor cytotoxicity (Ad-HSV1TK) with recruitment of dendritic cells to gliomas (Ad-Flt3L) to induce anti-glioma immunity. In experimental models this treatment induces powerful cytotoxic CD8 and CD4 T-dependent anti-glioma immunity, immunological memory, and the capacity to recognize neo-antigens. The trial was approved through a FDA-IND, and all institutional cttees. Treatment was administered intraoperatively following complete glioma resection in newly diagnosed tumors. The trial consisted of vector dose escalation, starting at 1x10^9 v.p., and increasing to 1x10^11 v.p. of each vector, through 6 cohorts of 3 patients each. Two cycles of 14 days of valacyclovir were administered to activate HSV1-TK cytotoxicity. Cycle 1 starts on Day 1–3 post surgery for 14 days, and Cycle 2 on Week 8–12. Standard radiation, i.e., 60 Gy in 2 Gy fractions over 6 weeks, with concurrent temozolomide, was followed by cyclic temozolomide. Examination of tumor samples at primary resection and first recurrence show an increase in the infiltration of inflammatory cells. The experimental treatment was well tolerated. An MTD was not reached. There were approx. 248 AEs, and 26 SAEs; these were not linked to treatment. As secondary outcome, median survival of contemporary controls was 604 days, and median survival of trial patients was 742 days. Our results show for the first time that reprogramming of the host’s brain immune system to recognize gliomas reveals a new approach for the treatment of highly malignant brain tumors. Clinical trial information: NCT01811992.

Idiopathic trigeminal neuralgia is one of the most common pain syndromes encountered in a typical neurosurgical practice. The approach to these patients is nuanced, and is based on their overall health status, the characteristics of their pain, and the distribution of symptoms. This chapter describes the assessment of a healthy patient with trigeminal neuralgia and provides key differential diagnoses of this pain syndrome. The counseling of the patient regarding treatment options is also described. Finally, the chapter outlines the operative management of a healthy patient using a microvascular decompression (MVD), including surgical pearls and strategies for complication avoidance and management.

Glossopharyngeal neuralgia is an uncommon, but devastating pain condition. It shares many features with trigeminal neuralgia, but predominantly affects the posterior tongue and pharynx. Since glossopharyngeal neuralgia pain is frequently triggered by swallowing or movement of the tongue, patients frequently present with weight loss and dehydration. This chapter describes the classic features of this condition, including its association with syncope. The medical management of glossopharyngeal neuralgia is outlined as a primary treatment modality. Surgical considerations are also described, including microvascular decompression or sectioning of the glossopharyngeal nerve. Surgical pearls for both of these procedures are outlined, as well as strategies for complication avoidance and management.

The treatment of spinal cord injury pain is one of the most challenging clinical problems in pain neurosurgery. It represents a type of deafferentation pain that resists most treatment modalities. And while ablative neurosurgical procedures have largely been abandoned in the treatment of deafferentation pain, it still plays an important role in transitional zone pain. This chapter outlines the essential clinical features of transitional zone pain following spinal cord injury and describes the use of dorsal root entry zone lesioning (DREZ) in its management. The decision-making process involved in offering this procedure is nuanced, and this chapter provides key considerations important in counseling patients prior to surgery.

BACKGROUND Radiation resistance is one of the major limitations for effective control of glioblastoma. Guanosine triphosphate (GTP) supplementation promotes glioblastoma radioresistance. Conversely, GTP depletion overcomes glioblastoma radioresistance by slowing the repair of radiation-induced DNA damage. Mycophenolate mofetil (MMF) inhibits de novo GTP synthesis by inhibiting the key enzyme, inosine-5′-monophosphate dehydrogenase, and radiosensitizes glioblastoma in mice. These pre-clinical findings have led to Phase 0/I Dose Escalation Study of Mycophenolate Mofetil Combined with Radiation Therapy in Recurrent Glioblastoma (NCT04477200) to measure the concentration of active metabolite of MMF in glioblastoma, and to determine the safe dose of MMF when given in combination with radiation. METHODS Key eligibility criteria are age ≥18, patients with Karnofsky Performance Scale score ≥60, and recurrent glioblastoma or gliosarcoma with clinical indication for re-irradiation (phase I) or re-resection or biopsy (phase 0). Those with tumor involving ≥3 lobes or leptomeningeal space or bevacizumab use within 8 weeks are excluded. Eight participants will receive MMF 500–2000 mg PO BID for one week before surgery (phase 0). Approximately 30 subjects will receive MMF 250–2000 mg PO BID (starting: 1000mg) on TITE-CRM dose escalation model (phase I). RESULTS From 7/2020 to 11/2020, two phase 0 and three phase I subjects have completed MMF treatment without notable toxicity. Additionally, correlative measurements of the activity of de novo GTP synthesis are explored. The anticipated study duration is 48 months. CONCLUSION The results of this trial will aid in designing a randomized clinical trial to determine the efficacy of MMF combined with chemoradiation in glioblastoma, and to define potential biomarkers for effectiveness. MMF is widely available and inexpensive, so if positive efficacy result is observed, a brisk acceptance of MMF combined with the standard of care is anticipated.

Purpose To evaluate the tolerability and efficacy of gemcitabine plus radiation therapy (RT) in this phase 1 study of patients with newly diagnosed malignant glioma (HGG). Patients and Methods Between 2004 and 2012, 29 adults with HGG were enrolled. After any extent of resection, RT (60 Gy over 6 weeks) was given concurrent with escalating doses of weekly gemcitabine. Using a time-to-event continual reassessment method, 5 dose levels were evaluated starting at 500 mg/m 2 during the last 2 weeks of RT and advanced stepwise into earlier weeks. The primary objective was to determine the recommended phase 2 dose of gemcitabine plus RT. Secondary objectives included progression-free survival, overall survival (OS), and long-term toxicity. Results Median follow-up was 38.1 months (range, 8.9-117.5 months); 24 patients were evaluable for toxicity. After 2005 when standard practice changed, patients with World Health Organization grade 4 tumors were no longer enrolled. Median progression-free survival for 22 patients with grade 3 tumors was 26.0 months (95% confidence interval [CI] 15.6-inestimable), and OS was 48.5 months (95% CI 26.8-inestimable). In 4 IDH mutated, 1p/19q codeleted patients, no failures occurred, with all but 1 alive at time of last follow-up. Seven with IDH mutated, non-codeleted tumors with ATRX loss had intermediate OS of 73.5 months (95% CI 32.8-inestimable). Six nonmutated, non-codeleted patients had a median OS of 26.5 months (95% CI 25.4-inestimable). The recommended phase 2 dose of gemcitabine plus RT was 750 mg/m 2 /wk given the last 4 weeks of RT. Dose reductions were most commonly due to grade 3 neutropenia; no grade 4 or 5 toxicities were seen. Conclusions Gemcitabine concurrent with RT is well-tolerated and yields promising outcomes, including in patients with adverse molecular features. It is a candidate for further study, particularly for poor-prognosis patient subgroups with HGG.

High grade gliomas (HGG) such as glioblastoma lack effective treatment with poor prognosis of median overall survival (OS) around 14-16 months with standard of care. Initiation of effective immune response against cancer requires functional dendritic cells, which are absent from the central nervous system, resulting in lack of anti-HGG immune responses. An effective anti-glioma immune response can be achieved by combining glioma cytotoxicity with HSV1-TK and valacyclovir, and recruitment of dendritic cells to the brain with Flt3L. This dual approach makes endogenous tumor antigens available to infiltrating dendritic cells in its microenvironment by causing: (i) dendritic cells' infiltration of gliomas, (ii) CD8+, CD4+ T cell immune cytotoxicity and memory, and (iii) the systemic immune system to recognize tumor neoantigens. We report the first in human phase I dose escalation trial of adenoviral vectors expressing HSV1-TK and Flt3L (NCT01811992). Injection of dose escalated HSV1-TK and Flt3L adenovectors (range 1x10^9 vp - 1x10^11 vp) to the tumor bed post-resection of newly diagnosed HGG was followed by two cycles of 14-day course of valacyclovir starting 1-3 days and 10-12 weeks post-op combined with standard of care upfront radiation, concurrent and adjuvant temozolomide. Key inclusion criteria were ages 18-75, KPS ≥70, and suspected newly diagnosed HGG amenable to gross total resection. Enrollment and vector injection occurred after frozen pathology confirmed HGG. Out of 18 patients, six are still alive. The primary endpoint of maximal tolerated dose was not reached and the experimental treatment was well tolerated without dose limiting toxicity. The secondary endpoint of OS is promising with median of 21.9 months (range 5.4-52.7). Five out of six patients (83%) who had re-resection at the time of suspected radiographic progression had treatment effect rather than true progression, and increase in markers for dendritic cells, CD4+ T cells, and macrophages were noted, indicating successful immunity recruitment consistent with pre-clinical findings. Updated survival data, as well as comparison to matched controls, and detailed toxicities will be presented at the time of the meeting. In conclusion, the use of dual adenoviral vectors expressing Flt3L and HSV1-TK is safe and well tolerated in newly diagnosed HGG patients. Our results indicate promising preliminary survival outcome and histological evidence of immune infiltration. Future studies to assess treatment efficacy is warranted. Citation Format: Pedro Lowenstein, Daniel Orringer, Yoshie Umemura, Oren Sagher, Jason Heth, Shawn Hervey-Jumper, Aaron Mammoser, Denise Leung, Ted Lawrence, Mishell Kim, Daniel Wahl, Paul McKeever, Sandra Camelo-Piragua, Andrew Lieberman, Sriram Venneti, Kait Verbal, Karen Sagher, Patrick Dunn, Daniel Zamler, Andrea Comba, David Altshuler, Lili Zhao, Karin Muraszko, Larry Junck, Maria G. Castro. First in human phase I trial of adenoviral vectors expressing Flt3L and HSV1-TK to treat newly diagnosed high-grade glioma by reprogramming the brain immune system [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT105.

OBJECTIVEMaximal safe tumor resection in language areas of the brain relies on a patient’s ability to perform intraoperative language tasks. Assessing the performance of these tasks during awake craniotomies allows the neurosurgeon to identify and preserve brain regions that are critical for language processing. However, receiving sedation and analgesia just prior to experiencing an awake craniotomy may reduce a patient’s wakefulness, leading to transient language and/or cognitive impairments that do not completely subside before language testing begins. At present, the degree to which wakefulness influences intraoperative language task performance is unclear. Therefore, the authors sought to determine whether any of 5 brief measures of wakefulness predicts such performance during awake craniotomies for glioma resection.METHODSThe authors recruited 21 patients with dominant hemisphere low- and high-grade gliomas. Each patient performed baseline wakefulness measures in addition to picture-naming and text-reading language tasks 24 hours before undergoing an awake craniotomy. The patients performed these same tasks again in the operating room following the cessation of anesthesia medications. The authors then conducted statistical analyses to investigate potential relationships between wakefulness measures and language task performance.RESULTSRelative to baseline, performance on 3 of the 4 objective wakefulness measures (rapid counting, button pressing, and vigilance) declined in the operating room. Moreover, these declines appeared in the complete absence of self-reported changes in arousal. Performance on language tasks similarly declined in the intraoperative setting, with patients experiencing greater declines in picture naming than in text reading. Finally, performance declines on rapid counting and vigilance wakefulness tasks predicted performance declines on the picture-naming task.CONCLUSIONSCurrent subjective methods for assessing wakefulness during awake craniotomies may be insufficient. The administration of objective measures of wakefulness just prior to language task administration may help to ensure that patients are ready for testing. It may also allow neurosurgeons to identify patients who are at risk for poor intraoperative performance.

INTRODUCTION: Accurate intraoperative diagnosis is essential for providing optimal neurosurgical care. In many centers caring for brain tumor patients, neuropathology resources are limited. To augment existing neuropathology resources, we developed and validated a new paradigm combining optical histology and artificial intelligence (AI) to accurately predict diagnosis during brain tumor surgery. METHODS: A total of 1026 specimens from 501 patients undergoing brain tumor resection at two tertiary hospitals were imaged using an optical technique, called stimulated Raman histology (SRH). SRH images were used to train and validate a convolutional neural network (CNN) for state-of-the-art computer vision. We redesigned the GoogleNet InceptionV3 CNN architecture to optimize performance on SRH histologic image fields of view (FOVs) and trained the network using 466 patients (3.1 million unique 300m2 FOVs) to classify into 13 common brain tumor subtypes. Final intraoperative diagnosis was determined using the most commonly predicted FOV diagnosis within each specimen. Model testing was completed on 1 million unique FOVs from 35 prospectively enrolled patients whose data was not included in the training set. RESULTS: In the validation set, our trained CNN differentiated lesional from normal tissue with 100% accuracy, surgical from nonsurgical lesions with 100% accuracy, glial from non-glial tumors with 100% accuracy. When evaluating our model for tumor subtype classification, we achieved an accuracy of 97% (35/36 patients) compared to final clinical diagnosis. Corresponding clinical frozen section diagnostic accuracy was 97% and interrater agreement between CNN and clinical frozen section diagnosis was near-perfect (k>0.96). The sole CNN error was misclassification of a WHO grade 1 pilocytic astrocytoma as a WHO grade II astrocytoma. CONCLUSION: Our prospective, multi-institutional validation suggests that AI can be applied to predict diagnosis in neurosurgical specimens in an automated fashion. AI-based diagnosis may ultimately be used to augment the current neuropathology workflow where resources are limited.

In this surgical video, the operative technique is presented for awake implantation of a thoracic paddle electrode for spinal cord stimulation. In the first stage, a laminotomy is performed with the patient under conscious sedation. Once the paddle is in optimal position, the patient is tested intraoperatively to confirm adequate coverage and absence of untoward side effects. This paddle electrode is used for the trial period. If the patient derives satisfactory pain relief during the trial, they are returned for the second stage implantation of pulse generator, without moving the initial paddle electrode now already placed in an optimal location. Particular attention in this video is provided toward the optimal positioning and technique for the awake laminotomy to ensure patient comfort and reliability during testing, the use of extension leads tunneled opposite the planned pulse generator site, and the method of removing extension leads to preserve the placement of the initial paddle electrode.

Distinguishing a tumor from non-neoplastic tissue is a challenging task during cancer surgery. Several attempts have been made to use visible or fluorescent agents to aid in the visualization of a tumor during surgery. We describe a novel method to delineate brain tumors, using a highly sensitive photoacoustic imaging technique that is enhanced by tumor-targeting blue nanoparticles serving as a contrast agent. Experiments on phantoms and on rat brains, ex vivo, demonstrate the high sensitivity of photoacoustic imaging in delineating tumors containing contrast agent at a concentration much lower than needed for visualization by the naked eye. The limit of detection of the system for the nanoparticles is about 0.77 μg/mL in water (equivalent to 0.84 μmol/L Coomassie Blue dye). The present exploratory study suggests that photoacoustic imaging, when used with strongly optical absorbing contrast agents, could facilitate cancer surgery intraoperatively by revealing the distribution and extent of the tumor.

In this paper, the authors present a physical model developed to simulate accurate external ventricular drain (EVD) placement with realistic haptic and visual feedbacks to serve as a platform for complete procedural training. Insertion of an EVD via ventriculostomy is a common neurosurgical procedure used to monitor intracranial pressures and/or drain CSF. Currently, realistic training tools are scarce and mainly limited to virtual reality simulation systems. The use of 3D printing technology enables the development of realistic anatomical structures and customized design for physical simulators. In this study, the authors used the advantages of 3D printing to directly build the model geometry from stealth head CT scans and build a phantom brain mold based on 3D scans of a plastinated human brain. The resultant simulator provides realistic haptic feedback during a procedure, with visualization of catheter trajectory and fluid drainage. A multiinstitutional survey was also used to prove content validity of the simulator. With minor refinement, this simulator is expected to be a cost-effective tool for training neurosurgical residents in EVD placement.

Over the past two decades, extent of resection has emerged as a significant prognostic factor in patients with low-grade gliomas. Greater extent of resection has been shown to improve overall survival, progression-free survival, and time to malignant transformation. The operative goal in the majority of low-grade glioma cases is to maximize extent of resection while avoiding post-operative neurologic deficits. Several advanced surgical techniques have been developed in an attempt to better achieve maximal safe resection. Intraoperative magnetic resonance imaging, fluorescence-guided surgery, intraoperative functional pathway mapping, and neuro-navigation are some of the most commonly utilized techniques with multiple studies to support their efficacy in glioma surgery. By utilizing these techniques either alone or in combination, patients harboring low-grade gliomas have a better prognosis with less surgical morbidity following tumor resection.

Hilar ectopic dentate granule cells (DGCs) are a salient feature of aberrant plasticity in human temporal lobe epilepsy (TLE) and most rodent models of the disease. Recent evidence from rodent TLE models suggests that hilar ectopic DGCs contribute to hyperexcitability within the epileptic hippocampal network. Here we investigate the intrinsic excitability of DGCs from humans with TLE and the rat pilocarpine TLE model with the objective of comparing the neurophysiology of hilar ectopic DGCs to their normotopic counterparts in the granule cell layer (GCL). We recorded from 36 GCL and 7 hilar DGCs from human TLE tissue. Compared with GCL DGCs, hilar DGCs in patient tissue exhibited lower action potential (AP) firing rates, more depolarized AP threshold, and differed in single AP waveform, consistent with an overall decrease in excitability. To evaluate the intrinsic neurophysiology of hilar ectopic DGCs, we made recordings from retrovirus-birthdated, adult-born DGCs 2–4 mo after pilocarpine-induced status epilepticus or sham treatment in rats. Hilar DGCs from epileptic rats exhibited higher AP firing rates than normotopic DGCs from epileptic or control animals. They also displayed more depolarized resting membrane potential and wider AP waveforms, indicating an overall increase in excitability. The contrasting findings between disease and disease model may reflect differences between the late-stage disease tissue available from human surgical specimens and the earlier disease stage examined in the rat TLE model. These data represent the first neurophysiological characterization of ectopic DGCs from human hippocampus and prospectively birthdated ectopic DGCs in a rodent TLE model.

Conventional methods for intraoperative histopathologic diagnosis are labour- and time-intensive, and may delay decision-making during brain-tumour surgery. Stimulated Raman scattering (SRS) microscopy, a label-free optical process, has been shown to rapidly detect brain-tumour infiltration in fresh, unprocessed human tissues. Here, we demonstrate the first application of SRS microscopy in the operating room using a portable fibre-laser-based microscope and unprocessed specimens from 101 neurosurgical patients. We also introduce an image-processing method—stimulated Raman histology (SRH)—that leverages SRS images to create virtual haematoxylin-and-eosin-stained slides, revealing essential diagnostic features. In a simulation of intraoperative pathologic consultation in 30 patients, we found a remarkable concordance of SRH and conventional histology for predicting diagnosis (Cohen’s kappa, κ > 0.89), with accuracy exceeding 92%. We also built and validated a multilayer perceptron based on quantified SRH image attributes that predicts brain-tumour subtype with 90% accuracy. Our findings provide insight into how SRH can now be used to improve the surgical care of brain-tumour patients. By taking advantage of stimulated Raman spectroscopy and fibre-laser technology, virtual histology images can be obtained in real time in the operating room, with diagnostic quality comparable with that achieved via conventional histopathology.

2019 Background: This is the initial report on a first in human Phase I dose escalation trial of the combination of two adenoviral vectors expressing HSV1-TK or Flt3L for the treatment of newly diagnosed, resectable malignant gliomas. The absence of functional dendritic cells from the brain precludes anti-brain tumor immune responses. We combined tumor cytotoxicity (Ad-HSV1TK) with recruitment of dendritic cells to the brain (Ad-Flt3L) to induce an effective anti-tumor immune response. This strategy induced an efficacious, cytotoxic CD8 and CD4 T-dependent immune response in many animal models of glioma. This immune response also generated anti-tumor memory, and the capacity for neoantigen recognition. Methods: The trial was approved by FDA and all institutional cttees. Treatment was administered intraoperatively following complete glioma resection in newly diagnosed tumors. The trial consisted of vector dose escalation, starting at 1x10^9 i.u., and increasing to 1x10^11 i.u. of each vector. Dose escalation proceeded by increasing the vector dose through a total of 6 combinations administered to 6 cohorts of 3 patients each. Two cycles of 14 days each of valacyclovir were administered to activate HSV1-TK cytotoxicity. Cycle 1 starts on Day 1-3 post surgery for 14 days, and Cycle 2 on Week 8-12. Standard radiation, i.e., 60 Gy in 2 Gy fractions over 6 weeks, with concurrent temozolomide, was followed by cyclic temozolomide. Results: Examination of tumor samples at primary resection and first recurrence show an increase in the infiltration of inflammatory cells. The experimental treatment was well tolerated. At this time the MTD has not been reached. There were approx. 248 AEs, and 26 SAEs; these have not been linked to treatment. At this time the MTD has not been reached. A secondary outcome is overall survival. Preliminary analysis of partial data may suggest that the combined viral vector therapy may provide a clinically significant survival. Conclusions: Our results show for the first time that reprogramming of the host’s brain immune system to recognize gliomas reveals a new approach for the treatment of highly malignant brain tumors. Clinical trial information: NCT01811992.

erebrovascular etiologies, including arteriovenous malformations (AVMs), account for up to 15% cases of C epilepsy (7). The risks of hemorrhage associated with these lesions have been well documented; however, the treatment of seizures in patients harboring cerebral AVMs is less well studied (16). Epilepsy is the most common clinical manifestation of unruptured AVMs and second only to hemorrhage in those with ruptures (12). Crawford et al. (4) studied the factors associated with AVMs that increase the likelihood of seizures and found that, overall, the incidence was low, with just 6% carrying a diagnosis of epilepsy before hemorrhage. This is in contrast to prior studies that cited an incidence of 17%e40% in unruptured AVMs (11, 13). Turjman et al. (16) reported their findings on seizure risk related to the angioarchitecture of the AVMs and found that superficial location with feeding by the external carotid artery, or a temporoparietal superficial location and feeding by the middle cerebral artery, were more predictive of epilepsy, an expected result when considering that proximity to cortex results in a more epileptogenic state. Most of these patients present with a first-time seizure; however, up to 43% of patients with newly diagnosed AVMs present with recurrent seizures (9).

Background The risk of suicide behaviours post–deep brain stimulation (DBS) surgery in Parkinson’s disease (PD) remains controversial. We assessed if suicide ideation and behaviours are more common in PD patients (1) randomised to DBS surgery versus best medical therapy (BMT); and (2) randomised to subthalamic nucleus (STN) versus globus pallidus interna (GPi) DBS surgery. Methods In Phase 1 of the Veterans Affairs CSP 468 study, 255 PD patients were randomised to DBS surgery (n=121) or 6 months of BMT (n=134). For Phase 2, a total of 299 patients were randomised to STN (n=147) or GPi (n=152) DBS surgery. Patients were assessed serially with the Unified Parkinson9s Disease Rating Scale Part I depression item, which queries for suicide ideation; additionally, both suicide behaviour adverse event data and proxy symptoms of increased suicide risk from the Parkinson9s Disease Questionnaire (PDQ-39) and the Short Form Health Survey (SF-36) were collected. Results In Phase 1, no suicide behaviours were reported, and new-onset suicide ideation was rare (1.9% for DBS vs 0.9% for BMT; Fisher9s exact p=0.61). Proxy symptoms of relevance to suicide ideation were similar in the two groups. Rates of suicide ideation at 6 months were similar for patients randomised to STN versus GPi DBS (1.5% vs 0.7%; Fisher9s exact p=0.61), but several proxy symptoms were worse in the STN group. Conclusions Results from the randomised, controlled phase of a DBS surgery study in PD patients do not support a direct association between DBS surgery and an increased risk for suicide ideation and behaviours.

Ventriculostomy is a common neurosurgical procedure with a relatively steep learning curve. A low-cost, high-fidelity simulator paired with procedure-specific performance measures would provide a safe environment to teach ventriculostomy procedural skills. The same validated simulation model could also allow for assessment of trainees' proficiencies with measures that align with Accreditation Council for Graduate Medical Education milestones. This study extends previous work to evaluate validity evidence from the simulator, its newly developed performance assessment, the Ventricolostomy Procedural Assessment Tool, and the Objective Structured Assessment for Technical Skills.After Institutional Review Board exemption, performance data were collected from 11 novice and 3 expert neurosurgeons (n = 14). Participants self-reported their ability to perform tasks on the simulator using the Ventricolostomy Procedural Assessment Tool, an 11-item, step-wise instrument with 5-point rating scales ranging from 1 (unable to perform) to 5 (performs easily and smoothly). De-identified operative performances were videotaped and independently rated by 3 neurosurgeons, using the Ventricolostomy Procedural Assessment Tool and Objective Structured Assessment for Technical Skills. We evaluated multiple sources of validity evidence (2014 Standards) to examine psychometric quality of the measures and to test our assumption that the tools could discriminate between novice and expert performances adequately. We used a multifacet Rasch model and traditional indices, such as Cronbach alpha, intraclass correlation, and Wilcoxon signed-rank test estimates.Validity evidence relevant to test content and response processes was supported adequately. Evidence of internal structure was supported by high interitem consistency (n = 0.95) and inter-rater agreement for most Ventricolostomy Procedural Assessment Tool items (Intraclass correlation coefficient = [0.00, 0.91]) and all Objective Structured Assessment for Technical Skills items (Intraclass correlation coefficient = [0.80, 0.93]). Overall, novices performed at a lower level than experts on both scales (P .05), supporting evidence relevant to relationships to other variables. Deeper analysis of novice/expert ratings indicated novices attained lower performances ratings for all Ventricolostomy Procedural Assessment Tool and Objective Structured Assessment for Technical Skills items, but statistical significance was only achieved for the Objective Structured Assessment for Technical Skills items (P .01). Rater bias estimates were favorable, supporting evidence relevant to consequences of testing.Despite a small sample, favorable evidence using current Standards supports the use of the novel simulator and both tools combined for skills training and performance assessment, but challenges (potential threats to validity) should be considered prior to implementation.

Object The extent of resection (EOR) is a known prognostic factor in patients with glioblastoma. However, gross-total resection (GTR) is not always achieved. Understanding the factors that prevent GTR is helpful in surgical planning and when counseling patients. The goal of this study was to identify demographic, tumor-related, and technical factors that influence EOR and to define the relationship between the surgeon's impression of EOR and radiographically determined EOR. Methods The authors performed a retrospective review of the electronic medical records to identify all patients who underwent craniotomy for glioblastoma resection between 2006 and 2009 and who had both preoperative and postoperative MRI studies. Forty-six patients were identified and were included in the study. Image analysis software (FIJI) was used to perform volumetric analysis of tumor size and EOR based on preoperative and postoperative MRI. Using multivariate analysis, the authors assessed factors associated with EOR and residual tumor volume. Perception of resectability was described using bivariate statistics, and survival was described using the log-rank test and Kaplan-Meier curves. Results The EOR was less for tumors in eloquent areas (p = 0.014) and those touching ventricles (p = 0.031). Left parietal tumors had significantly greater residual volume (p = 0.042). The average EOR was 91.0% in this series. There was MRI-demonstrable residual tumor in 69.6% of cases (16 of 23) in which GTR was perceived by the surgeon. Expert reviewers agreed that GTR could be safely achieved in 37.0% of patients (17 of 46) in this series. Among patients with safely resectable tumors, radiographically complete resection was achieved in 23.5% of patients (4 of 17). An EOR greater than 90% was associated with a significantly greater 1-year survival (76.5%) than an EOR less than 90% (p = 0.005). Conclusions The authors' findings confirm that tumor location affects EOR and suggest that EOR may also be influenced by the surgeon's ability to judge the presence of residual tumor during surgery. The surgeon's ability to judge completeness of resection during surgery is commonly inaccurate. The authors' study confirms the impact of EOR on 1-year survival.

Conventional histopathology with hematoxylin & eosin (H&E) has been the gold standard for histopathological diagnosis of a wide range of diseases. However, it is not performed in vivo and requires thin tissue sections obtained after tissue biopsy, which carries risk, particularly in the central nervous system. Here we describe the development of an alternative, multicolored way to visualize tissue in real-time through the use of coherent Raman imaging (CRI), without the use of dyes. CRI relies on intrinsic chemical contrast based on vibrational properties of molecules and intrinsic optical sectioning by nonlinear excitation. We demonstrate that multicolor images originating from CH(2) and CH(3) vibrations of lipids and protein, as well as two-photon absorption of hemoglobin, can be obtained with subcellular resolution from fresh tissue. These stain-free histopathological images show resolutions similar to those obtained by conventional techniques, but do not require tissue fixation, sectioning or staining of the tissue analyzed.

Expert evaluation of electrocorticographic (ECoG) recordings forms the linchpin of seizure onset zone localization in the evaluation of epileptic patients for surgical resection. Numerous methods have been developed to analyze these complex recordings, including uni-variate (characterizing single channels), bi-variate (comparing channel pairs) and multivariate measures. Developing reliable algorithms may be helpful in clinical tasks such as localization of epileptogenic zones and seizure anticipation, as well as enabling better understanding of neuronal function and dynamics. Recently we have developed the frequency-entropy (F-E) similarity measure, and have tested its capability in mapping the epileptogenic zones. The F-E similarity measure compares time-frequency characterizations of two recordings. In this study, we examine the method's principles and utility and compare it to previously described bi-variate correspondence measures such as correlation, coherence, mean phase coherence and spectral comparison methods. Specially designed synthetic signals were used for illuminating theoretical differences between the measures. Intracranial recordings of four epileptic patients were then used for the measures' comparative analysis by creating a mean inter-electrode matrix for each of the correspondence measures and comparing the structure of these matrices during the inter-ictal and ictal periods. We found that the F-E similarity measure is able to discover spectral and temporal features in data which are hidden for the other measures and are important for foci localization.

Transorbital penetrating injury (TPI), an uncommon subset of head trauma, requires prompt multidisciplinary surgical intervention. While numerous case reports appear in the literature, there is a lack of discrete recommendations for initial evaluation, surgical intervention, and postoperative care of patients with TPI. A retrospective review of 4 cases of TPI at the University of Michigan Health System was undertaken to assess for diagnosis, treatment, and follow-up. In addition, a PubMed search using the terms “penetrating orbital trauma,” “penetrating orbital injury,” “transorbital penetration,” and “transorbital penetrating injury” were used to search for articles discussing the presentation and management of penetrating orbital trauma. All 4 of the patients at the University of Michigan underwent focused physical examination performed by a multidisciplinary trauma team followed by dedicated maxillofacial and head CT scanning. The patients' treatments varied, depending on the mechanism and extent of the injury. An analysis of the case series presented here as well as other published cases suggests an algorithm for diagnosis and treatment for patients with TPI, which includes focused evaluation, diagnostic imaging with maxillofacial CT scanning, and management of the injury that focuses on the path of penetration and the presence of the foreign body in situ at the time of presentation. Magnetic resonance imaging is indicated in patients who have indwelling wooden foreign bodies. Angiography should be performed in patients with suspected vascular injury. Treatment decisions should be made by a multidisciplinary team with input from neurosurgery, ophthalmology, otolaryngology, and maxillofacial surgery.

Deep-brain stimulation is the surgical procedure of choice for patients with advanced Parkinson's disease. The globus pallidus interna and the subthalamic nucleus are accepted targets for this procedure. We compared 24-month outcomes for patients who had undergone bilateral stimulation of the globus pallidus interna (pallidal stimulation) or subthalamic nucleus (subthalamic stimulation).At seven Veterans Affairs and six university hospitals, we randomly assigned 299 patients with idiopathic Parkinson's disease to undergo either pallidal stimulation (152 patients) or subthalamic stimulation (147 patients). The primary outcome was the change in motor function, as blindly assessed on the Unified Parkinson's Disease Rating Scale, part III (UPDRS-III), while patients were receiving stimulation but not receiving antiparkinsonian medication. Secondary outcomes included self-reported function, quality of life, neurocognitive function, and adverse events.Mean changes in the primary outcome did not differ significantly between the two study groups (P=0.50). There was also no significant difference in self-reported function. Patients undergoing subthalamic stimulation required a lower dose of dopaminergic agents than did those undergoing pallidal stimulation (P=0.02). One component of processing speed (visuomotor) declined more after subthalamic stimulation than after pallidal stimulation (P=0.03). The level of depression worsened after subthalamic stimulation and improved after pallidal stimulation (P=0.02). Serious adverse events occurred in 51% of patients undergoing pallidal stimulation and in 56% of those undergoing subthalamic stimulation, with no significant between-group differences at 24 months.Patients with Parkinson's disease had similar improvement in motor function after either pallidal or subthalamic stimulation. Nonmotor factors may reasonably be included in the selection of surgical target for deep-brain stimulation. (ClinicalTrials.gov numbers, NCT00056563 and NCT01076452.)

Object The authors developed a wavelet-based measure for quantitative assessment of neural background activity during intraoperative neurophysiological recordings so that the boundaries of the subthalamic nucleus (STN) can be more easily localized for electrode implantation. Methods Neural electrophysiological data were recorded in 14 patients (20 tracks and 275 individual recording sites) with dopamine-sensitive idiopathic Parkinson disease during the target localization portion of deep brain stimulator implantation surgery. During intraoperative recording, the STN was identified based on audio and visual monitoring of neural firing patterns, kinesthetic tests, and comparisons between neural behavior and the known characteristics of the target nucleus. The quantitative wavelet-based measure was applied offline using commercially available software to measure the magnitude of the neural background activity, and the results of this analysis were compared with the intraoperative conclusions. Wavelet-derived estimates were also compared with power spectral density measurements. Results The wavelet-derived background levels were significantly higher in regions encompassed by the clinically estimated boundaries of the STN than in the surrounding regions (STN, 225 ± 61 μV; ventral to the STN, 112 ± 32 μV; and dorsal to the STN, 136 ± 66 μV). In every track, the absolute maximum magnitude was found within the clinically identified STN. The wavelet-derived background levels provided a more consistent index with less variability than measurements with power spectral density. Conclusions Wavelet-derived background activity can be calculated quickly, does not require spike sorting, and can be used to identify the STN reliably with very little subjective interpretation required. This method may facilitate the rapid intraoperative identification of STN borders.

Nanoparticles have the potential for advancing the diagnosis, operative management and adjuvant therapy brain tumors in the future. Nanoparticle-based MR contrast agents have the potential to uncover portions of tumor, especially along the tumor-brain interface, that would have been unclear with traditional gadolinium-enhanced MRI. In addition, several nanoparticles, developed with the objective of allowing the surgeon to see tumor margins intraoperatively, may ultimately enable neurosurgeons to improve the extent of brain tumor resection. Moreover, the delivery of chemotherapy and non-traditional therapies to brain tumors will likely be greatly improved by nanoparticle based-drug delivery devices. As our knowledge of their pharmacology and long-term health effects expands, nanoparticles are likely to play a central role in the future management of the brain tumor patient.

Objective Accurate localization of functionally significant brain regions reduces risks of post-operative neurological deficits. The gold standard for presurgical brain mapping is subdural electrocortical stimulation (ECS), which is an open-cranium surgical procedure. Functional MRI (fMRI) may be a noninvasive alternative if it can be shown that fMRI and ECS maps are spatially consistent. We formulate new 3D current density weighted ECS–fMRI correspondence indices and illustrate their use on human data. Methods Current density maps were computed for simulated and human datasets by solving the electrostatic Laplace equation. The proposed indices were characterized and compared with fixed radii and Euclidean distance indices. Results Results from simulated datasets showed that the proposed indices quantify correspondence between fMRI and the ECS truth predictably, and provide conspicuous sensitivity increase from fixed radii indices, whereas Euclidean distances may not be suitable measures of the correspondence. Conclusions The proposed indices reflect contextual information from surrounding electrodes and may be physiologically more meaningful in evaluating ECS–fMRI correspondence. Significance To identify safe limits of resection, an ECS map requires placement of electrodes on a patient’s brain. Our proposed indices accurately quantify ECS–fMRI correspondence and may be used to evaluate fMRI as a noninvasive alternative for defining resection limits.