Fully automated delineation of the optic radiation for surgical planning using clinically feasible sequences.

Quadrantanopia caused by inadvertent severing of Meyer's Loop of the optic radiation is a well-recognised complication of temporal lobectomy for conditions such as epilepsy. Dissection studies indicate that the anterior extent of Meyer's Loop varies considerably between individuals. Quantifying this for individual patients is thus an important step to improve the safety profile of temporal lobectomies. Previous attempts to delineate Meyer's Loop using diffusion MRI tractography have had difficulty estimating its full anterior extent, required manual ROI placement, and/or relied on advanced diffusion sequences that cannot be acquired routinely in most clinics. Here we present CONSULT: a pipeline that can delineate the optic radiation from raw DICOM data in a completely automated way via a combination of robust pre-processing, segmentation, and alignment stages, plus simple improvements that bolster the efficiency and reliability of standard tractography. We tested CONSULT on 696 scans of predominantly healthy participants (539 unique brains), including both advanced acquisitions and simpler acquisitions that could be acquired in clinically acceptable timeframes. Delineations completed without error in 99.4% of the scans. The distance between Meyer's Loop and the temporal pole closely matched both averages and ranges reported in dissection studies for all tested sequences. Median scan-rescan error of this distance was 1 mm. When tested on two participants with considerable pathology, delineations were successful and realistic. Through this, we demonstrate not only how to identify Meyer's Loop with clinically feasible sequences, but also that this can be achieved without fundamental changes to tractography algorithms or complex post-processing methods.

Alexander disease: The story behind an eponym.

In 1949, William Stewart Alexander (1919-2013), a young pathologist from New Zealand working in London, reported the neuropathological findings in a 15-month-old boy who had developed normally until the age of seven months, but thereafter had progressive enlargement of his head and severe developmental delay. The most striking neuropathological abnormality was the presence of numerous Rosenthal fibers in the brain. The distribution of these fibers suggested to Alexander that the primary pathological change involved astrocytes. In the next 15 years, five similar patients were reported, and in 1964 Friede recognized these cases reflected a single disease process and coined the eponym "Alexander's disease" to describe the disorder. In the 1960s, electron microscopy confirmed that Rosenthal fibers were localized to astrocytes. In 2001, it was shown that Alexander disease is caused by mutations in the gene encoding glial fibrillary acidic protein, the major intermediate filament protein in astrocytes. Although the clinical, imaging, and pathological manifestations of Alexander disease are now well known, few people are familiar with Alexander's career. Although he did not make a further contribution to the literature on Alexander disease, his observations and accurate interpretation of the neuropathology have justified the continued use of the eponym "Alexander disease."

Properties and Implementation of 3-Dimensionally Printed Models in Spine Surgery: A Mixed-Methods Review With Meta-Analysis.

OBJECTIVE: Spine surgery addresses a wide range of spinal pathologies. Potential applications of 3-dimensional (3D) printed in spine surgery are broad, encompassing education, planning, and simulation. The objective of this study was to explore how 3D-printed spine models are implemented in spine surgery and their clinical applications. METHODS: Methods were combined to create a scoping review with meta-analyses. PubMed, EMBASE, the Cochrane Library, and Scopus databases were searched from 2011 to 7 September 2021. Results were screened independently by 2 reviewers. Studies utilizing 3D-printed spine models in spine surgery were included. Articles describing drill guides, implants, or nonoriginal research were excluded. Data were extracted according to reporting guidelines in relation to study information, use of model, 3D printer and printing material, design features of the model, and clinical use/patient-related outcomes. Meta-analyses were performed using random-effects models. RESULTS: Forty articles were included in the review, 3 of which were included in the meta-analysis. Primary use of the spine models included preoperative planning, education, and simulation. Six printing technologies were utilized. A range of substrates were used to recreate the spine and regional pathology. Models used for preoperative and intraoperative planning showed reductions in key surgical performance indicators. Generally, feedback for the tactility, utility, and education use of models was favorable. CONCLUSIONS: Replicating realistic spine models for operative planning, education, and training is invaluable in a subspeciality where mistakes can have devastating repercussions. Future study should evaluate the cost-effectiveness and the impact spine models have of spine surgery outcomes.

Evaluation of 3D Printed Burr Hole Simulation Models Using 8 Different Materials.

OBJECTIVE: 3D printing is increasingly used to fabricate three-dimensional neurosurgical simulation models, making training more accessible and economical. 3D printing includes various technologies with different capabilities for reproducing human anatomy. This study evaluated different materials across a broad range of 3D printing technologies to identify the combination that most precisely represents the parietal region of the skull for burr hole simulation. METHODS: Eight different materials (polyethylene terephthalate glycol, Tough PLA, FibreTuff, White Resin, BoneSTN, SkullSTN, polymide [PA12], glass-filled polyamide [PA12-GF]) across 4 different 3D printing processes (fused filament fabrication, stereolithography, material jetting, selective laser sintering) were produced as skull samples that fit into a larger head model derived from computed tomography imaging. Five neurosurgeons conducted burr holes on each sample while blinded to the details of manufacturing method and cost. Qualities of mechanical drilling, visual appearance, skull exterior, and skull interior (i.e., diploë) and overall opinion were documented, and a final ranking activity was performed along with a semistructured interview. RESULTS: The study found that 3D printed polyethylene terephthalate glycol (using fused filament fabrication) and White Resin (using stereolithography) were the best models to replicate the skull, surpassing advanced multimaterial samples from a Stratasys J750 Digital Anatomy Printer. The interior (e.g., infill) and exterior structures strongly influenced the overall ranking of samples. All neurosurgeons agreed that practical simulation with 3D printed models can play a vital role in neurosurgical training. CONCLUSIONS: The study findings reveal that widely accessible desktop 3D printers and materials can play a valuable role in neurosurgical training.

Pituitary Metastasis of Renal Cell Carcinoma Characterized by 18F-Prostate-Specific Membrane Antigen-1007 PET/CT.

ABSTRACT: Renal cell carcinoma (RCC) is one of the most common oncological diagnoses worldwide. Accurate staging and restaging imaging continue to be a priority in clinical practice as 20% to 30% of patients present with advanced metastatic disease at diagnosis, and 20% to 30% develop recurrence after surgical resection. We present a case of a 71-year-old man presenting with an isolated pituitary RCC metastasis accurately defined on 18F-prostate-specific membrane antigen-1007 masquerading as a macroadenoma on conventional imaging (CT and MRI). This demonstrates the potential utility of 18F-prostate-specific membrane antigen-1007 in characterizing RCC brain metastasis.

Emergent craniotomy in rural and regional settings: recommendations from a tertiary neurosurgery unit: diagnosis and surgical decision-making.

Largely attributed to the tyranny of distance, timely transfer of patients with major traumatic brain injuries (TBI) from rural or regional hospitals to metropolitan trauma centres is not always feasible. This has warranted emergent craniotomies to be undertaken by non-neurosurgeons at their local hospitals with previous acceptable results reported in regional Australia. Our institution endorses this ongoing potentially life-saving practice when necessary and emphasize the need for neurosurgical units to provide ongoing TBI education to peripheral hospitals. In this first of a two-part narrative review, the authors describe the recommended diagnostic pathway for patients with a suspected TBI presenting to rural or regional hospitals and discuss local surgical management options in the presence or absence of a CT scanner.

Emergent craniotomy in rural and regional settings - recommendations from a tertiary neurosurgery unit: surgical technique and future prospects.

Kenneth G Jamieson described the emergent craniotomy for traumatic brain injuries (TBI) in the rural and regional setting back in 1965 in his book 'A First Notebook Of Head Injury'. Since then, there has been successful use of the technique in peripheral hospitals prior to the safe transfer of patients to metropolitan trauma centres. Although the procedure can be daunting in inexperienced hands, our institution supports ongoing education to continue implementation of trauma craniotomies by non-neurosurgeons if it means another life is potentially saved. Here we describe the surgical technique for an emergent craniotomy and craniectomy. Although the surgical technique has been described elsewhere, we have done so in a simplified 10-step approach with consideration of available resources in the peripheral hospital setting and the added pearls from the experience of a metropolitan neurosurgical unit. We also discuss future prospects for undertaking neurosurgical operations in peripheral hospitals but with intra-operative tele-surgery monitoring and supervision.

Unilateral hydrocephalus from a gangliocytoma-somatotrophinoma: first reported case.

SUMMARY: Although pituitary macroadenomas often cause mass effects on surrounding structures, it is extremely rare for pituitary lesions to disturb cerebrospinal fluid circulation. Sellar gangliocytoma-pituitary adenomas (SGPAs) are also extremely rare. Here we report the unique case of a man with the unusual combination of acromegaly from an SGPA, who presented with unilateral hydrocephalus. A 60-year-old man presented with rapid neurological deterioration, bitemporal hemianopia, and acromegalic features. Neuroimaging revealed a large sellar lesion extending superiorly into the left foramen of Monro, causing acute obstructive unilateral hydrocephalus. External ventricular drain placement improved consciousness immediately. Biochemical assessment confirmed acromegaly. Following trans-sphenoidal debulking, histology revealed a mixed gangliocytoma/sparsely-granulated somatotrophinoma. Despite the residual disease, his vision recovered remarkably, low-dose cabergoline controlled residual excess growth hormone (GH) secretion, and the residual tumour has remained extremely stable over 2 years. Hydrocephalus is an extremely rare complication of pituitary lesions, and unilateral hydrocephalus has never been reported previously. GH secretion in SGPAs is more common than for pituitary adenomas in general, raising questions regarding the aetiology and therapeutic approach to this rare combination tumour. LEARNING POINTS: Pituitary tumours most commonly present with symptoms related to endocrine disturbance or mass effects upon visual pathways (e.g. optic chiasm, nerves in the lateral cavernous sinus). However, extremely rarely, pituitary masses may disrupt cerebrospinal fluid (CSF) circulation resulting in hydrocephalus. Sellar gangliocytomas are very rare tumours and most of them are hybrid tumours with pituitary adenomas (SGPAs). SGPAs are typically indolent and may be functioning or non-functioning tumours. Growth hormone (GH)-producing SGPAs are less likely to respond to somatostatin agonists than classic somatotrophinomas. Primary surgical debulking via a trans-sphenoidal approach was effective in this individual, leading to the restoration of CSF circulation and improvement in visual disturbance, while also negating the need for permanent CSF diversion despite the residual tumour burden.

Properties and Characteristics of Three-Dimensional Printed Head Models Used in Simulation of Neurosurgical Procedures: A Scoping Review.

BACKGROUND: Intracranial surgery can be complex and high risk. Safety, ethical and financial factors make training in the area challenging. Head model 3-dimensional (3D) printing is a realistic training alternative to patient and traditional means of cadaver and animal model simulation. OBJECTIVE: To describe important factors relating to the 3D printing of human head models and how such models perform as simulators. METHODS: Searches were performed in PubMed, the Cochrane Library, Scopus, and Web of Science. Articles were screened independently by 3 reviewers using Covidence software. Data items were collected under 5 categories: study information; printers and processes; head model specifics; simulation and evaluations; and costs and production times. RESULTS: Forty articles published over the last 10 years were included in the review. A range of printers, printing methods, and substrates were used to create head models and tissue types. Complexity of the models ranged from sections of single tissue type (e.g., bone) to high-fidelity integration of multiple tissue types. Some models incorporated disease (e.g., tumors and aneurysms) and artificial physiology (e.g., pulsatile circulation). Aneurysm clipping, bone drilling, craniotomy, endonasal surgery, and tumor resection were the most commonly practiced procedures. Evaluations completed by those using the models were generally favorable. CONCLUSIONS: The findings of this review indicate that those who practice surgery and surgical techniques on 3D-printed head models deem them to be valuable assets in cranial surgery training. Understanding how surgical simulation on such models affects surgical performance and patient outcomes, and considering cost-effectiveness, are important future research endeavors.

Management trends and outcomes of pineal germinoma in a multi-institutional Australian cohort.

Pineal germinoma is rare with high cure rates following craniospinal radiotherapy. Efforts to reduce the radiotherapy dose and field via combination with chemotherapy suggest comparable disease control and reduced neurocognitive impairments, while the efficacy of immunotherapy in pineal germinoma remains undetermined. This report aimed to review clinical outcomes in patients treated for pineal germinoma in Queensland, Australia, and assess for Programmed Death-Ligand1 (PD-L1) expression. Patients who commenced radiation and/or chemotherapy for pineal germinoma from 2005 to 2017 were retrospectively identified using Queensland Oncology Online database. Demographic, diagnostic, treatment, and outcome data was obtained from electronic medical records. PD-L1 immuno-histochemistry was performed on available specimens. Eighteen patients with long-term follow-up data were identified. Median age at diagnosis was 16.8 years (range 9-46 years). Diagnosis was made histologically in fifteen patients, and radiologically in three. All patients underwent radiotherapy (median 36 Gy (range 21-54 Gy)) with lower median dose delivered with whole ventricle irradiation (12/18patients) than craniospinal irradiation (5/18patients). Sixteen patients received chemotherapy preceding radiotherapy. All patients are alive at median 7.25 years from primary treatment completion (range 2.03-13.1 years). Relapse occurred in three patients (16.67%) following treatment response, all of whom achieved remission following high-dose chemotherapy with stem-cell support and craniospinal radiotherapy. Post-treatment functional outcomes were similarly excellent. PD-L1 expression was low (1-49% cells) or negative in 87% of tumours tested but results were confounded by specimen quality and availability. Reduced-dose radiotherapy with chemotherapy does not compromise outcome and is standard of care at this institution. Immunotherapy is unlikely to become standard treatment in the near future.

Classic type intradural extramedullary ependymoma of the lumbar spine: A new case report of a usual tumour in an unusual location.

Classic type intradural extramedullary (IDEM) ependymomas of the lumbar spine are rare entities. Only two such cases have previously been reported in the literature. Here the authors report a new case and describe radiological, surgical and histological findings as well as review the literature. Unlike previously encountered lumbar IDEM ependymomas, this case was an incidental finding and surgically managed on the grounds of radiological progression over 8 years.

Q-Cell Glioblastoma Resource: Proteomics Analysis Reveals Unique Cell-States are Maintained in 3D Culture.

Glioblastoma (GBM) is a treatment-refractory central nervous system (CNS) tumour, and better therapies to treat this aggressive disease are urgently needed. Primary GBM models that represent the true disease state are essential to better understand disease biology and for accurate preclinical therapy assessment. We have previously presented a comprehensive transcriptome characterisation of a panel (n = 12) of primary GBM models (Q-Cell). We have now generated a systematic, quantitative, and deep proteome abundance atlas of the Q-Cell models grown in 3D culture, representing 6167 human proteins. A recent study has highlighted the degree of functional heterogeneity that coexists within individual GBM tumours, describing four cellular states (MES-like, NPC-like, OPC-like and AC-like). We performed comparative proteomic analysis, confirming a good representation of each of the four cell-states across the 13 models examined. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified upregulation of a number of GBM-associated cancer pathway proteins. Bioinformatics analysis, using the OncoKB database, identified a number of functional actionable targets that were either uniquely or ubiquitously expressed across the panel. This study provides an in-depth proteomic analysis of the GBM Q-Cell resource, which should prove a valuable functional dataset for future biological and preclinical investigations.

Primary intraventricular abscess of the third ventricle.

Intraventricular abscess is a rare pathology. We present a case of primary intraventricular abscess in an immunocompetent 22 year old male. We review the literature and discuss our management of this case with aspiration via neuroendoscopy.

Progressive dysembryoplastic neuroepithelial tumour.

Dysembryoplastic neuroepithelial tumour (DNET) is a benign tumour characterised by cortical location and presentation with drug resistant partial seizures in children. Recently the potential for malignant transformation has been reported, however progression without malignant transformation remains rare. We report a case of clinical and radiologic progression of a DNET in a girl 10 years after initial biopsy.

Autologous T-cell therapy for cytomegalovirus as a consolidative treatment for recurrent glioblastoma.

Glioblastoma multiforme (GBM) is one of the most aggressive human brain malignancies. Even with optimal treatment, median survival is less than 6 months for patients with recurrent GBM. Immune-based therapies have the potential to improve patient outcome by supplementing standard treatment. Expression of human cytomegalovirus (CMV) antigens in GBM tissues provides the unique opportunity to target viral antigens for GBM therapy. Here, we report findings of a formal clinical assessment of safety and potential clinical efficacy of autologous CMV-specific T-cell therapy as a consolidative treatment for recurrent GBM. From a total of 19 patients with recurrent GBM, CMV-specific T cells were successfully expanded from 13 patients (68.4%), 11 of whom received up to four T-cell infusions. Combination therapy based on T-cell infusion and chemotherapy was well tolerated, and we detected only minor adverse events. The overall survival of these patients since first recurrence ranged from 133 to 2,428 days, with a median overall survival of 403 days. Most importantly, 4 of 10 patients that completed the treatment remained progression free during the study period. Furthermore, molecular profiling of CMV-specific T-cell therapy from these patients revealed distinct gene expression signatures, which correlated with their clinical response. Our study suggests that a combination therapy with autologous CMV-specific T cells and chemotherapy is a safe novel treatment option and may offer clinical benefit for patients with recurrent GBM.

Bilateral retrocerebellar arachnoid cysts exerting mass effect and associated with cerebellar tonsillar ectopia in an otherwise healthy adult.

Rarely, midline or unilateral posterior fossa arachnoid cysts (ACs) exert local mass effect resulting in the symptoms and signs of cerebellar and brainstem dysfunction. These cysts are sometimes seen in conjunction with cerebellar tonsillar ectopia (TE), although the relationship between these two entities is unclear. Bilateral ACs in the posterior fossa are virtually unprecedented. We describe the case of a 33-year-old man with a history of multiple minor head injuries observed to harbour asymptomatic, bilateral cerebrospinal fluid-density collections over the cerebellar hemispheres. Six years later, he presented with headaches, limb paraesthesias, and drop attacks. Computed tomography, magnetic resonance imaging, and operative findings during burrhole drainage of the lesions showed bilateral posterior fossa ACs, with associated cerebellar TE of 11 mm. The cysts partially recurred, necessitating reopening of the burrholes, after which the patient's symptoms resolved entirely. We then discuss the challenges in diagnosing this unusual case, the relationship between AC and TE, and the role of minor head injury in the symptomatic progression of AC.

Endoscopic surgery of skull base chordomas.

Objective To assess our clinical experience in treating midline intracranial pathology using minimally invasive surgical techniques. Design Retrospective chart review of patients undergoing endoscopic endonasal resection of clival chordomas. Setting Two tertiary referral centers in Australia and New Zealand. Main Outcome Measures Patients were assessed by intraoperative findings (macroscopic resection rate, tumor size, and operative complications) and clinical outcomes (residual disease, postoperative complications, recurrence rate, and mortality). Results Fourteen patients underwent endoscopic resection of clival chordomas (seven primary, seven revision) with a mean follow-up of 41.45 months (3 to 104 months). Macroscopic resection rates were 71% and 29%, respectively. Mean operative time was 386 minutes. Overall cerebrospinal fluid (CSF) leak rate was 3/14 (21%) and, using the nasoseptal flap, it was 0/5 (0%). Two patients developed late recurrence; one died of disease and one was treated with intensity modulated radiation therapy. Overall mortality was 2/14 (14%). Conclusion Endoscopic resection of clival chordomas is a safe and viable alternative to the traditional open approach. The nasoseptal flap is an excellent method of obtaining a watertight skull base closure. Furthermore, this series highlighted the fact that the primary attempt at surgery offers the best chance to achieve a total resection.

Endoscopic endonasal resection of anterior skull base meningiomas.

OBJECTIVE: Anterior cranial fossa (ACF) meningiomas are difficult to surgically manage. Endoscopic transnasal approaches have increasingly been used as a minimally invasive route and thus offer significant advantages. However, a paucity of literature describing the intraoperative challenges and postoperative outcomes of this technique still exists. STUDY DESIGN: Case series with chart review. SETTING: The Royal Adelaide Hospital, Flinders Medical Centre, Wellington Hospital. SUBJECTS AND METHODS: Fifteen consecutive patients who underwent endoscopic resection of ACF meningiomas between 2004 and 2010 by the South Australian and Wellington Skull Base Units. Demographic and clinical information was compiled by reviewing patient charts and operation notes. Safety and efficacy of the procedure, role of a team approach, and areas for further improvement were analyzed. RESULTS: Of the patients, 87% were women. Tumor locations: 8 olfactory groove, 2 tuberculum sellae, 1 clinoidal, 1 jugum sphenoidale, 1 planum sphenoidale, 1 subfrontal, and 1 midline ACF floor. Commonest presenting symptom was visual change. Mean volume of tumor was 25.69 cm(3), with a size area of 7.28 cm(2). Five were revision cases. None had previous endonasal surgery. Average operating times decreased over time. Gross total removal was achieved in 14, with no deaths. Four patients had postoperative cerebrospinal fluid (CSF) leak. Rate of CSF leak decreased over time. Sixty percent of patients reported visual improvement. Two patients had radiological evidence of recurrence. CONCLUSION: ACF meningiomas can be safely removed endonasally, offering significant advantages over the traditional transcranial approach for suitable tumors. Early audit of this approach shows results achieved by this unit are comparable with the published literature.

Incidence and management of high grade glioma in Maori and non-Maori patients.

A retrospective analysis of 301 patients was undertaken between 1993 and 2003 to evaluate the relationship of ethnicity with incidence, treatment and survival in patients undergoing surgery for high grade glioma (HGG) in New Zealand. There was no difference in age standardised incidence of HGG in Maori compared to non-Maori patients; 4.2/100,000 person years (95% confidence interval [CI] 2.6-6.9) versus 4.1 (95% CI 3.6-4.6). Maori were more likely to have complete tumour resection (odds ratio 3.59 (95% CI 1.01-12.76)) but waited 1.32 (95% CI 0.98-1.79) times longer for radiotherapy. Median survival was 29 weeks with poorer survival in Maori compared to non-Maori (hazard ratio 1.55 [95% CI 0.95-2.55]). We concluded that the incidence of HGG in Maori is similar to non-Maori. However, Maori with HGG have higher rates of complete resection but wait longer for radiotherapy and may have poorer overall survival than non-Maori.

Endoscopic transsphenoidal resection of a mid-clival meningioma.

Advances in transsphenoidal endoscopic surgery have allowed difficult clival tumours such as meningiomas causing effacement of the pons and basilar artery to be approached by this technique. We report a clival meningioma resected via a transsphenoidal endoscopic approach.