3D Models as a Source for Neuroanatomy Education: A Stepwise White Matter Dissection Using 3D Images and Photogrammetry Scans.

White matter dissection (WMD) involves isolating bundles of myelinated axons in the brain and serves to gain insights into brain function and neural mechanisms underlying neurological disorders. While effective, cadaveric brain dissections pose certain challenges mainly due to availability of resources. Technological advancements, such as photogrammetry, have the potential to overcome these limitations by creating detailed three-dimensional (3D) models for immersive learning experiences in neuroanatomy. This study aimed to provide a detailed step-by-step WMD captured using two-dimensional (2D) images and 3D models (via photogrammetry) to serve as a comprehensive guide for studying white matter tracts of the brain. One formalin-fixed brain specimen was utilized to perform the WMD. The brain was divided in a sagittal plane and both cerebral hemispheres were stored in a freezer at -20 °C for 10 days, then thawed under running water at room temperature. Micro-instruments under an operating microscope were used to perform a systematic lateral-to-medial and medial-to-lateral dissection, while 2D images were captured and 3D models were created through photogrammetry during each stage of the dissection. Dissection was performed with comprehensive examination of the location, main landmarks, connections, and functions of the white matter tracts of the brain. Furthermore, high-quality 3D models of the dissections were created and housed on SketchFab®, allowing for accessible and free of charge viewing for educational and research purposes. Our comprehensive dissection and 3D models have the potential to increase understanding of the intricate white matter anatomy and could provide an accessible platform for the teaching of neuroanatomy.

Elucidating the pathogenesis behind arteriovenous malformations of the central nervous system: a bibliometric analysis.

Arteriovenous malformations (AVMs) are vascular malformations of the central nervous system (CNS) with potential for significant consequences. The exact pathophysiologic mechanism of AVM formation is not fully understood. This study aims to evaluate bibliometric parameters and citations of the literature of AVMs to provide an overview of how the field has evolved. We performed an electronic search on Web of Science to identify the top 100 published and indexed articles with the highest number of citations discussing the pathogenesis of AVMs. This study yielded 1863 articles, of which the top 100 were selected based on the highest total citation count. These articles included 24% basic science, 46% clinical, and 30% review articles. The most-cited article was a clinical article from 2003, and the most recent was published in 2022. The median number of authors was 6, with the highest being 46 for a clinical article. The top 5 journals were identified, with the highest impact factor being 20.1. 13 countries were identified, with the US contributing the most articles (approximately 70%). Regarding genes of investigation, VEGF was one of the early genes investigated, while more interested in RAS/MAPK has been garnered since 2015. There is a growing interest in AVM genomics and pathogenesis research. While progress has been made in understanding clinical aspects and risk factors, the exact pathophysiological mechanisms and genetic basis of AVM formation remain incompletely understood. Further investigation of key genes in AVM pathogenesis can allow identification of potential therapeutic targets.

360° around the orbit: key surgical anatomy of the microsurgical and endoscopic cranio-orbital and orbitocranial approaches.

OBJECTIVE: Several pathologies either invade or arise within the orbit. These include meningiomas, schwannomas, and cavernous hemangiomas among others. Although several studies describing various approaches to the orbit are available, no study describes all cranio-orbital and orbitocranial approaches with clear, surgically oriented anatomical descriptions. As such, this study aimed to provide a comprehensive guide to the microsurgical and endoscopic approaches to and through the orbit. METHODS: Six formalin-fixed, latex-injected cadaveric head specimens were dissected in the surgical anatomy laboratory at the authors' institution. In each specimen, the following approaches were modularly performed: endoscopic transorbital approaches (ETOAs), including a lateral transorbital approach and a superior eyelid crease approach; endoscopic endonasal approaches (EEAs), including those to the medial orbit and optic canal; and transcranial approaches, including a supraorbital approach, a fronto-orbital approach, and a 3-piece orbito-zygomatic approach. Each pertinent step was 3D photograph-documented with macroscopic and endoscopic techniques as previously described. RESULTS: Endoscopic endonasal approaches to the orbit afforded excellent access to the medial orbit and medial optic canal. Regarding ETOAs, the lateral transorbital approach afforded excellent access to the floor of the middle fossa and, once the lateral orbital rim was removed, the cavernous sinus could be dissected and the petrous apex drilled. The superior eyelid approach provides excellent access to the anterior cranial fossa just superior to the orbit, as well as the dura of the lesser wing of the sphenoid. Craniotomy-based approaches provided excellent access to the anterior and middle cranial fossa and the cavernous sinus, except the supraorbital approach had limited access to the middle fossa. CONCLUSIONS: This study outlines the essential surgical steps for major cranio-orbital and orbitocranial approaches. Endoscopic endonasal approaches offer direct medial access, potentially providing bilateral exposure to optic canals. ETOAs serve as both orbital access and as a corridor to surrounding regions. Cranio-orbital approaches follow a lateral-to-medial, superior-to-inferior trajectory, progressively allowing removal of protective bony structures for proportional orbit access.

The utility of PET for detecting corticotropinomas in Cushing disease: a scoping review.

While magnetic resonance imaging (MRI) is the current standard imaging method for diagnosing and localizing corticotropinomas in Cushing disease, it can fail to detect adenomas in up to 40% of cases. Recently, positron emission tomography (PET) has shown promise as a diagnostic tool to detect pituitary adenomas in Cushing disease. We perform a scoping review to characterize the uses of PET in diagnosing Cushing disease, with a focus on describing the types of PET investigated and defining PET-positive disease. A scoping review was conducted following the PRISMA-ScR guidelines. Thirty-one studies fulfilled our inclusion criteria, consisting of 10 prospective studies, 8 retrospective studies, 11 case reports, and 2 illustrative cases with a total of 262 patients identified. The most commonly utilized PET modalities in prospective/retrospective studies were FDG PET (n = 5), MET PET (n = 5), 68 Ga-DOTATATE PET (n = 2), 13N-ammonia PET (n = 2), and 68 Ga-DOTA-CRH PET (n = 2). MRI positivity ranged from 13 to 100%, while PET positivity ranged from 36 to 100%. In MRI-negative disease, PET positivity ranged from 0 to 100%. Five studies reported the sensitivity and specificity of PET, which ranged from 36 to 100% and 50 to 100%, respectively. PET shows promise in detecting corticotropinomas in Cushing disease, including MRI-negative disease. MET PET has been highly investigated and has demonstrated excellent sensitivity and specificity. However, preliminary studies with FET PET and 68 Ga-DOTA-CRH PET show promise for achieving high sensitivity and specificity and warrant further investigation.

Association of moyamoya vasculopathy with autoimmune disease: a systematic review and pooled analysis.

Despite more than six decades of extensive research, the etiology of moyamoya disease (MMD) remains unknown. Inflammatory or autoimmune (AI) processes have been suggested to instigate or exacerbate the condition, but the data remains mixed. The objective of the present systematic review was to summarize the available literature investigating the association of MMD and AI conditions as a means of highlighting potential treatment strategies for this subset of moyamoya patients. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the PubMed, Embase, Scopus, Web of Science, and Cochrane databases were queried to identify studies describing patients with concurrent diagnoses of MMD and AI disease. Data were extracted on patient demographics, clinical outcomes, and treatment. Stable or improved symptoms were considered favorable outcomes, while worsening symptoms and death were considered unfavorable. Quantitative pooled analysis was performed with individual patient-level data. Of 739 unique studies identified, 103 comprising 205 unique patients (80.2% female) were included in the pooled analysis. Most patients (75.8%) identified as Asian/Pacific Islanders, and the most commonly reported AI condition was Graves' disease (57.6%), with 55.9% of these patients presenting in a thyrotoxic state. Of the 148 patients who presented with stroke, 88.5% of cases (n = 131) were ischemic. Outcomes data was available in 152 cases. There were no significant baseline differences between patients treated with supportive therapy alone and those receiving targeted immunosuppressant therapy. Univariable logistic regression showed that surgery plus medical therapy was more likely than medical therapy alone to result in a favorable outcome. On subanalysis of operated patients, 94.1% of patients who underwent combined direct and indirect bypass reported favorable outcomes, relative to 76.2% of patients who underwent indirect bypass and 82% who underwent direct bypass (p < 0.05). On univariable analysis, the presence of multiple AI disorders was associated with worse outcomes relative to having a single AI disorder. Autoimmune diseases have been uncommonly reported in patients with MMD, but the presence of multiple AI comorbidities portends poorer prognosis. The addition of surgical intervention appears to improve outcomes and for patients deemed surgical candidates, combined direct and indirect bypass appears to offer better outcomes that direct or indirect bypass alone.

The evolving landscape of pilocytic astrocytoma: a bibliometric analysis of the top-100 most cited publications.

BACKGROUND: Pilocytic astrocytomas are the most common low-grade glioma of the central nervous system that typically occurs in children, and much research has been dedicated to characterizing their molecular features and clinical courses. We provide an overview of the current literature through the use of a bibliometric analysis of the top 100 most cited publications discussing pilocytic astrocytomas. METHODS: We identified the top 100 most cited publications discussing pilocytic astrocytomas. Articles were ranked based on the number of citations. Descriptive statistics and univariate analysis were used to determine any trends or significant differences in the data. RESULTS: Of the top 100 articles, 50 were basic science (50%), 34 were clinical (34%), and 16 were review (16%). The number of citations ranged from 79 to 921, with 123 being the median. The US had the most first authors and principal authors (n = 53 and n = 54, respectively). Years of publication had a left-skewed distribution and peaked during 2011 with 12 articles published in that year. Sixty percent of basic science articles investigated BRAF/MAPK pathways, while 67.6% of clinical articles focused on evaluating treatment options for pilocytic astrocytomas. Compared to basic science and clinical articles, review articles were published more recently (p < 0.001), had fewer authors (p = 0.025) and were published in journals with higher impact factors (p = 0.022). CONCLUSION: Research regarding pilocytic astrocytomas has increased over the past three decades. Future directions of research point towards employing targeted therapies and discovering additional cellular pathways contributing to disease pathogenesis.

Management strategies for pediatric patients with tectal gliomas: a systematic review.

Pediatric tectal gliomas generally have a benign clinical course with the majority of these observed radiologically. However, patients often need treatment for obstructive hydrocephalus and occasionally require cytotoxic therapy. Given the lack of level I data, there is a need to further characterize management strategies for these rare tumors. We have therefore performed the first systematic review comparing various management strategies. The literature was systematically searched from January 1, 2000, to July 30, 2020, to identify studies reporting treatment strategies for pediatric tectal gliomas. The systematic review included 355 patients from 14 studies. Abnormal ocular findings-including gaze palsies, papilledema, diplopia, and visual field changes-were a common presentation with between 13.6 and 88.9% of patients experiencing such findings. CSF diversion was the most performed procedure, occurring in 317 patients (89.3%). In individual studies, use of CSF diversion ranged from 73.1 to 100.0%. For management options, 232 patients were radiologically monitored (65.4%), 69 received resection (19.4%), 30 received radiotherapy (8.4%), and 19 received chemotherapy (5.4%). When examining frequencies within individual studies, chemotherapy ranged from 2.5 to 29.6% and radiotherapy ranged from 2.5 to 28.6%. Resection was the most variable treatment option between individual studies, ranging from 2.3 to 100.0%. Most tectal gliomas in the pediatric population can be observed through radiographic surveillance and CSF diversion. Other forms of management (i.e., chemotherapy and radiotherapy) are warranted for more aggressive tumors demonstrating radiological progression. Surgical resection should be reserved for large tumors and/or those that are refractory to other treatment modalities.

Strategies, considerations, and recent advancements in the development of liquid biopsy for glioblastoma: a step towards individualized medicine in glioblastoma.

OBJECTIVE: Glioblastoma (GBM) is a devasting primary brain tumor with less than a 5% 5-year survival. Treatment response assessment can be challenging because of inflammatory pseudoprogression that mimics true tumor progression clinically and on imaging. Developing additional noninvasive assays is critical. In this article, the authors review various biomarkers that could be used in developing liquid biopsies for GBM, along with strengths, limitations, and future applications. In addition, they present a potential liquid biopsy design based on the use of an extracellular vesicle-based liquid biopsy targeting nonneoplastic extracellular vesicles. METHODS: The authors conducted a current literature review of liquid biopsy in GBM by searching the PubMed, Scopus, and Google Scholar databases. Articles were assessed for type of biomarker, isolation methodology, analytical techniques, and clinical relevance. RESULTS: Recent work has shown that liquid biopsies of plasma, blood, and/or CSF hold promise as noninvasive clinical tools that can be used to diagnose recurrence, assess treatment response, and predict patient outcomes in GBM. Liquid biopsy in GBM has focused primarily on extracellular vesicles, cell-free tumor nucleic acids, and whole-cell isolates as focal biomarkers. GBM tumor signatures have been generated via analysis of tumor gene mutations, unique RNA expression, and metabolic and proteomic alterations. Liquid biopsies capture tumor heterogeneity, identifying alterations in GBM tumors that may be undetectable via surgical biopsy specimens. Finally, biomarker burden can be used to assess treatment response and recurrence in GBM. CONCLUSIONS: Liquid biopsy offers a promising avenue for monitoring treatment response and recurrence in GBM without invasive procedures. Although additional steps must be taken to bring liquid biopsy into the clinic, proof-of-principle studies and isolation methodologies are promising. Ultimately, CSF and/or plasma-based liquid biopsy is likely to be a powerful tool in the neurosurgeon's arsenal in the near future for the treatment and management of GBM patients.

Does surgical management still play a role in the management of ectopic lingual thyroid: Institutional experience and systematic review of the literature.

OBJECTIVE: Management of ectopic lingual thyroid (ELT) must balance the morbidity of disease with the morbidity of treatment. We investigate clinical outcomes associated with modern treatment options and analyze the role of transoral surgery in the treatment algorithm for ELT. METHODS: This was a retrospective chart review of ELT patients treated at a tertiary care center from 1/1/1979 to 12/31/2019. In addition, a systematic review of the literature from 1979 to 2021 for reports of ELT was performed. Symptoms defined as high-risk were dysphagia, dysphonia, dyspnea, neck swelling, bleeding, and obstructive sleep apnea (OSA). RESULTS: 36 patients within the institutional cohort (IC) and 224 cases in the systematic review (SRC) met criteria. The most common presenting symptoms for both cohorts were dysphagia, globus sensation, and dysphonia. One third of each cohort were hypothyroid, while 3% (n = 1) and 9% (n = 21) of the IC and SRC, respectively, had clinical suspicion of malignancy at presentation. 27% (n = 10) of the IC and 55% (n = 121) of the SRC underwent surgical therapy. There was a 4% (3/72) transoral bleed rate for all patients undergoing transoral surgery. Other reported complications were minor. There were no tracheostomies, and no deaths. Among observed, medically treated, and surgically treated patients, symptoms improved during follow up for 43% or 68% in the IC and SRC, respectively. Following surgery, symptoms improved or resolved for 86% or 93% in the IC and SRC, respectively. CONCLUSIONS: Asymptomatic ELTs with no concern for malignancy can be managed with observation. Patients with mild symptoms or hypothyroidism may trial thyroid suppressive therapy or RAI. RAI can be considered for patients with high-risk symptoms. For patients with symptoms resistant to conservative therapy, concern for malignancy or high-risk symptoms not conducive to RAI, surgery should be considered. Transoral approaches offer acceptable morbidity, and most patients experience resolution of symptoms following this approach.

HIT in the head: a systematic review of cerebral venous sinus thrombosis in classical and autoimmune heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) causes thrombosis and thrombocytopenia, usually due to prior heparin exposure, so-called classical HIT. However, in the autoimmune form, the signs and symptoms of HIT occur without prior heparin exposure. Development of cerebral venous sinus thrombosis (CVST) secondary to HIT is a rare occurrence, with relatively few reports in the literature. There is a need to better understand the clinical presentation and treatment paradigms in these rare cases. Therefore, we present the first systematic review of CVST occurring in classical and autoimmune HIT. Cases of HIT-induced CVST were identified through a systematic search of Pubmed from the date of inception to March 2021. Literature search revealed 21 cases of HIT and associated CVST with six cases (28.6%) of autoimmune HIT. Patients presented with signs and symptoms consistent with increased intracranial pressure, intracerebral hemorrhage (ICH), and/or focal neurologic deficits. Headache was the most common symptom with 12 patients (60.0%) presenting as such. 10 patients (47.6%) included in the study developed ICH. Non-heparin anticoagulants, especially direct thrombin inhibitors, were the first-line treatment for the majority of patients (55.6%). Intravenous immunoglobulin (IVIG) was used as treatment for select patients (16.7%) with autoimmune HIT. Few patients received surgical intervention for CVST (14.3%) or ICH (30.0%). Four patients had a full recovery, four patients had residual deficits, and seven patients ultimately expired. Symptoms of HIT-induced CVST are often related to CNS dysfunction. Non-heparin anticoagulants are important to treat CVST, even when patients have concomitant ICH, and may be supplemented with IVIG if treating autoimmune HIT. Rapid identification and treatment of HIT-induced CVST is imperative in order to prevent morbidity and mortality.

International trends in grant and fellowship funding awarded to women in neurosurgery.

OBJECTIVE: Metric tracking of grant funding over time for academic neurosurgeons sorted by gender informs the current climate of career development internationally for women in neurosurgery. METHODS: Multivariate linear trend analysis of grant funding awarded to neurosurgeons in the NIH and World Research Portfolio Online Reporting Tools Expenditures and Results (RePORTER) was performed. Traveling fellowships for international neurosurgery residents sponsored by the AANS and Congress of Neurological Surgeons (CNS) were also analyzed. RESULTS: Within the US, funding awarded to female neurosurgeons has remained static from 2009 to 2019 after adjusting for inflation and overall trends in NIH funding (ß = -$0.3 million per year, p = 0.16). Internationally, female neurosurgeons represented 21.7% (n = 5) of project leads for World RePORTER grants. Traveling fellowships are also an important building block for young international female neurosurgeons, of which 7.4% (n = 2) of AANS international traveling fellowships and 19.4% (n = 7) of AANS/CNS pediatrics international traveling fellowships are women. CONCLUSIONS: Over the past decade, funding has increased in neurosurgery without a concordant increase in funding awarded to women. Recognition of this trend is essential to focus efforts on research and career development opportunities for women in neurosurgery. Worldwide, female neurosurgeons head one-fifth of the funded project leads and constitute a minority of international traveling fellowships awarded by organized neurosurgery.

Surgical Treatment of Hemifacial Spasm via Microvascular Decompression of a Large, Ectatic Vertebral Artery.

Hemifacial spasm is a neuromuscular disorder caused by compression of the facial nerve at the nerve root entry zone, often due to ectatic or aberrant vasculature. Pathologic compression of the nerve-brainstem interface results in involuntary, paroxysmal contractions of ipsilateral facial muscles that may cause considerable impairments in quality of life. For those with severe symptoms, have positive imaging demonstrating vascular compression, or who fail other management modalities, 1 2 3 4 microvascular decompression offers potential definitive treatment. 5 6 Traditionally, nonabsorbable packing agent is used to pack between the nerve and offending vascular structure. However, for large and more complex arterial structures, simple nonabsorbable padding is often not sufficient. In this operative video, we demonstrate microvascular decompression for intractable hemifacial spasm in a 52-year-old female using a specialized sling tacked to the petrous dura for management of a large, ectatic vertebral artery. Following a standard left retrosigmoid craniotomy, an atheromatous ectatic vertebral artery was identified. We fashioned a bovine pericardium sling around the vessel and used a permanent aneurysm clip to secure it to an incision portion of petrous dura. We subsequently identified potential additional facial nerve root compression by anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA) branches, which were elevated and secured using Teflon felt packing. Following elevation of all three vessels, the lateral spread response resolved. At 2 weeks postoperatively, the patient reported substantial relief in her hemifacial spasms and endorsed highly improved quality of life.

The Mayo, Cushing, and Osler Influence on A. L. Rhoton: A Historical Vignette of the Interconnectedness Between Highly Influential Neurosurgery Leaders over 100 Years.

The careers of the Mayo brothers, Harvey Cushing, and Sir William Osler greatly shaped medical and surgical practice in the late 19th century and early 20th century and created a legacy to influence decades of physicians to follow. Additionally, these individuals were instrumental in the founding of neurosurgery as a distinct surgical specialty. Alongside these great men, Dr. Albert L. Rhoton Jr., revolutionized neurosurgical practice through his study of neuroanatomy and development of microsurgical technique in the second half of the 20th century. This review of the interactions and relationships between the Mayo brothers, Cushing, and Osler and their influences on Rhoton highlights the 100-year-long interconnectedness shared between these giants in the history of neurosurgery.

Full Recovery of Hearing After Resection of a Large Epidermoid Tumor at the Cerebellopontine Angle: 2-Dimensional Operative Video.

Epidermoid tumors are benign, slow-growing lesions, originating from misplaced ectodermal cells that become trapped during neural tube closure.1 The cerebellopontine angle (CPA) is the most common intracranial location for epidermoid tumors, accounting for approximately 60% of cases.2 Treatment of epidermoid tumors consists of surgical resection, with the goal of gross total resection.3 Here, we describe the case of a patient with a large epidermoid tumor at the CPA causing near-complete hearing loss, who remarkably experienced full recovery of hearing after resection of the tumor. The patient is a 37-year-old woman who presented to our clinic with a CPA tumor causing severe hearing loss consisting of class D hearing and a word recognition score of 5% on audiological examination. Radiographically, the tumor demonstrated significant mass effect on the right cranial nerves VII and VIII with prominent extension into the internal auditory canal. Given the patient's profound hearing loss, she consented to receive a right retrosigmoid craniotomy for resection of the lesion. Although cranial nerves VII and VIII were heavily invested in the tumor, we were able to systematically resect the lesion from the CPA and internal auditory canal, and achieve a gross total resection. Histological examination confirmed the diagnosis of an epidermoid tumor. Remarkably, the patient's audiogram at 3-month follow-up demonstrated complete recovery of hearing in her right ear with a word recognition score of 100% and normal hearing sensitivity across all tested frequencies.

The 2-by-2 Inch "Key Window" in the Upper Extremity: An Anatomical Appraisal of the Accessibility and Proximity of the Major Nerves and Vessels.

BACKGROUND: The brachial plexus is a network of nerves located between the neck and axilla, which receives input from C5-T1. Distally, the nerves and blood vessels that supply the arm and forearm form a medial neurovascular bundle. The purpose of this study was to illustrate that a peripheral nerve dissection via a 2 × 2 inch window would allow for identification and isolation of the major nerves and blood vessels that supply the arm and forearm. METHODS: A right side formalin-fixed latex-injected cadaveric arm was transected at the proximal part of the axillary fold and included the scapular attachments. Step-by-step anatomical dissection was carried out and documented with three-dimensional digital imaging. RESULTS: A 2 × 2 inch window centered 2 inches distal to the axillary fold on the medial surface of the arm enabled access to the major neurovascular structures of the arm and forearm: the median nerve, ulnar nerve, medial antebrachial cutaneous nerve, radial nerve and triceps motor branches, musculocutaneous nerve and its biceps and brachialis branches and lateral antebrachial cutaneous nerve, basilic vein and brachial artery and vein, and profunda brachii artery. CONCLUSIONS: Our study demonstrates that the majority of the neurovascular supply in the arm and forearm can be accessed through a 2 × 2 inch area in the medial arm. Although this "key window" may not be entirely utilized in the operative setting, our comprehensive didactic description of peripheral nerve dissection in the cadaver laboratory can help in safer identification of complex anatomy encountered during surgical procedures.

Lower Cranial Nerve Schwannomas: Cohort Study and Systematic Review.

BACKGROUND AND OBJECTIVES: Schwannomas originating from the lower cranial nerves (LCNS) are rare and pose a significant surgical challenge. Resection is the mainstay treatment; however, risk of treatment morbidity is considerable, and the available literature regarding differential treatment outcomes in this vulnerable population is sparse. METHODS: A single-institution cohort study and systematic literature review of LCNS were performed. RESULTS: Fifty-eight patients were included: 34 underwent surgical resection and 24 underwent stereotactic radiosurgery (SRS). The median age at diagnosis was 48 years (range 17-74). Presenting symptoms were dysphagia (63%), dysarthria/hypophonia (47%), imbalance (33%), and hearing loss/tinnitus (30%). Tumor size was associated with surgical resection, as compared with initial SRS (4.1 cm vs 1.5 cm, P = .0001). Gross total resection was obtained in 52%, with tumor remnants predominantly localized to the jugular foramen (62%). Post-treatment worsening of symptoms occurred in 68% of surgical and 29% of SRS patients ( P = .003). Postoperative symptoms were mostly commonly hypophonia/hoarseness (63%) and dysphagia (59%). Seven patients (29%) had new neurological issues after SRS treatment, but symptoms were overall milder. The median follow-up was 60 months (range 12-252); 98% demonstrated meaningful clinical improvement. Eighteen surgical patients (53%) underwent adjuvant radiation at a median of 5 months after resection (range 2-32). At follow-up, tumor control was 97% in the surgical cohort and 96% among SRS patients. CONCLUSION: Although LCNS resection is potentially morbid, most postoperative deficits are transient, and patients achieve excellent tumor control-particularly when paired with adjuvant SRS. For minimally symptomatic patients undergoing surgical intervention, we advise maximally safe resection with intracapsular dissection to preserve nerve integrity where possible. For residual or as a primary treatment modality, SRS is associated with low morbidity and high rates of long-term tumor control.

Patterns of recurrence and disease progression in patients with positive-margin olfactory neuroblastoma following primary resection.

OBJECTIVE: Olfactory neuroblastoma (ONB) is a rare, malignant tumor of the sinonasal tract that arises from olfactory epithelium. Although surgery is the preferred first-line treatment, tumor involvement of adjacent structures may preclude the ability to achieve negative margins during initial resection. Herein, the authors examine the oncological outcomes of patients with positive margins after primary resection of ONB, with the aim of determining predictors of disease progression and patterns of recurrence. METHODS: The authors performed an institutional review of 25 patients with positive-margin ONB after resection. Cox survival analyses were used to determine any statistically significant predictors of worse progression-free survival (PFS) and overall survival (OS). RESULTS: A total of 93 patients who were diagnosed with ONB were identified, of whom 25 patients had positive margins following their primary resection. Eleven (44%) had a delayed finding of positive margins that were initially negative in the operating room but returned as positive on final pathology. Four patients had subtotal resection (STR), whereas the remaining patients underwent gross-total resection. Twenty-four patients received adjuvant radiotherapy (96%), and 15 additionally received adjuvant chemotherapy (60%). Fourteen patients (56%) experienced recurrence/progression at a median time of 35 months following resection (IQR 19-70 months). Local recurrence occurred in 10 patients (40%), regional in 9 (36%), and distant metastasis in 2 (8%). In Cox survival analyses, the 5-year PFS and OS were 55.1% and 79.2%, respectively. Kadish stage D was predictive of worse PFS in univariate (hazard ratio [HR] 15.67, 95% CI 3.38-72.61, p < 0.001) and multivariate (HR 15.46, 95% CI 1.45-164.91, p = 0.023) analyses. Hyams grade, adjuvant chemotherapy, and primary radiotherapy were not associated with PFS. Furthermore, Kadish stage D and STR were predictive of worse OS in univariate analysis (HR 12.64, 95% CI 2.03-78.86, p = 0.007; HR 7.31, 95% CI 1.45-36.84, p = 0.016; respectively). However, local and regional recurrence was not associated with worse OS. CONCLUSIONS: Approximately half of patients with positive-margin ONB may experience disease recurrence. Patients with an advanced disease stage (Kadish D) may have a higher likelihood of developing recurrence/progression. Furthermore, patients with tumor burden following resection (STR and Kadish D) may have worse OS. However, in positive-margin ONB with no gross disease following initial resection, the presence of disease recurrence does not significantly alter survival when receiving salvage therapy.

Barriers to neurosurgery for medical students: a national study focused on the intersectionality of gender and race.

OBJECTIVE: Despite 51.2% of medical school graduates being female, only 29.8% of neurosurgery residency applicants are female. Furthermore, only 12.6% of neurosurgery applicants identify as underrepresented in medicine (URM). Evaluating the entry barriers for female and URM students is crucial in promoting the equity and diversity of the neurosurgical workforce. The objective of this study was to evaluate barriers to neurosurgery for medical students while considering the interaction between gender and race. METHODS: A Qualtrics survey was distributed widely to US medical students, assessing 14 factors of hesitancy toward neurosurgery. Likert scale responses, representing statement agreeability, converted to numeric values on a 7-point scale were analyzed by Mann-Whitney U-test and ANOVA comparisons with Bonferroni correction. RESULTS: Of 540 respondents, 68.7% were female and 22.6% were URM. There were 22.6% male non-URM, 7.4% male URM, 53.5% female non-URM, and 15.2% female URM respondents. The predominant reasons for hesitancy toward neurosurgery included work/life integration, length of training, competitiveness of residency position, and perceived malignancy of the field. Females were more hesitant toward neurosurgery due to maternity/paternity needs (p = 0.005), the absence of seeing people like them in the field (p < 0.001), and opportunities to pursue health equity work (p < 0.001). Females were more likely to have difficulties finding a mentor in neurosurgery who represented their identities (p = 0.017). URM students were more hesitant toward neurosurgery due to not seeing people like them in the field (p < 0.001). Subanalysis revealed that when students were stratified by both gender and URM status, there were more reasons for hesitancy toward neurosurgery that had significant differences between groups (male URM, male non-URM, female URM, and female non-URM students), suggesting the importance of intersectionality in this analysis. CONCLUSIONS: The authors highlight the implications of gender and racial diversity in the neurosurgical workforce on medical student interest and recruitment. Their findings suggest the importance of actively working to address these barriers, including 1) maternity/paternity policy reevaluation, standardization, and dissemination; and 2) actively providing resources for the creation of mentorship relationships for both women and URM students in an effort to create a workforce that aligns with the changing demographics of medical graduates to continue to improve diversity in neurosurgery.

Photogrammetry scans for neuroanatomy education - a new multi-camera system: technical note.

Photogrammetry scans has directed attention to the development of advanced camera systems to improve the creation of three-dimensional (3D) models, especially for educational and medical-related purposes. This could be a potential cost-effective method for neuroanatomy education, especially when access to laboratory-based learning is limited. The aim of this study was to describe a new photogrammetry system based on a 5 Digital Single-Lens Reflex (DSLR) cameras setup to optimize accuracy of neuroanatomical 3D models. One formalin-fixed brain and specimen and one dry skull were used for dissections and scanning using the photogrammetry technique. After each dissection, the specimens were placed inside a new MedCreator® scanner (MedReality, Thyng, Chicago, IL) to be scanned with the final 3D model being displayed on SketchFab® (Epic, Cary, NC) and MedReality® platforms. The scanner consisted of 5 cameras arranged vertically facing the specimen, which was positioned on a platform in the center of the scanner. The new multi-camera system contains automated software packages, which allowed for quick rendering and creation of a high-quality 3D models. Following uploading the 3D models to the SketchFab® and MedReality® platforms for display, the models can be freely manipulated in various angles and magnifications in any devices free of charge for users. Therefore, photogrammetry scans with this new multi-camera system have the potential to enhance the accuracy and resolution of the 3D models, along with shortening creation time of the models. This system can serve as an important tool to optimize neuroanatomy education and ultimately, improve patient outcomes.