Hemangiopericytomas (HPC) are widely recognized for their aggressive clinical behavior. We report a large multicenter study, through the International Gamma Knife Research Foundation reviewing management and outcome following stereotactic radiosurgery (SRS) for recurrent or newly-discovered HPC’s. Methods: Eight centers participated, reviewing a total of 90 patients harboring 133 tumors. Prior treatments included embolization (n = 8), chemotherapy (n=2), and fractionated radiotherapy (n=34). The median tumor volume at the time of SRS was 4.9 ml (range 0.2-42.4 ml). WHO-grade II (typical) HPC’s formed 78.9% (n=71) of the cohort. The median margin and maximal doses delivered were 15 Gy (2.8-24) and 32 Gy (8-51), respectively. The median clinical and radiographic follow-up period was 59 months (6-190) and 59 months (6-183), respectively. Results: At last follow-up, 55% of tumors and 62.2% of patients demonstrated local tumor control. New remote intracranial tumors were found in 27.8%. 24.4% of patients developed extra-cranial metastases. Adverse radiation effects were noted in 6.7%. The overall survival was 91.5%, 82.1%, 73.9%, 56.7%, and 53.7% at 2, 4, 6, 8, and 10 years, respectively, after initial SRS. Local progression free survival was 81.7%, 66.3%, 54.5%, 37.2%, and 25.5% at 2, 4, 6, 8, and 10 years, respectively, after initial SRS. In our cohort, 32 patients underwent 48 repeat SRS procedures for 76 lesions. Margin dose greater than 16 Gy (p=0.037) and tumor histology (p=0.006) were shown to influence PFS. Conclusions: SRS provides a reasonable rate of local tumor control and a low risk of adverse effects

Gamma knife radiosurgery (GKRS) is well-established in the management of inaccessible, recurrent, or residual benign skull base meningiomas. Most series report clinical outcome parameters and complications in the short -intermediate period after radiosurgery. Reports of long-term tumor control and neurological status are still lacking. Objective: We report the presentation, treatment, and long-term outcome of skull base meningiomas after GKRS. Methods: From a prospectively collected IRB approved database, we selected patients with a WHO grade I skull base meningioma treated with a single-session GKRS and a minimum of 60 months follow up. 135 patients, 54.1% males (n=73) form the cohort. Median age was 54 years (19-80). Median tumor volume was 4.7 cm3 (0.5-23). Median margin dose was 15 Gy (7.5-36). Median follow up was 102.5 months (60.1-235.4). Patient and tumor characteristics were assessed to determine predictors of neurological function and tumor progression. Results: At last follow up, tumor volume control was achieved in 88.1% (n=119). Post-GKRS clinical improvement or stability was reported in 61.5%. The 5, 10, and 15 years actuarial progression free survival rates are 100%, 95.4%, and 68.8%, respectively. Favorable outcome (both tumor control and clinical preservation/improvement) was attained in 60.8% (n=79). Pre-GKRS performance status (KPS) was shown to influence tumor progression (p=0.0001) and post-GKRS clinical improvement / preservation (p=0.003). Conclusion: GKRS offers a highly durable rate of tumor control for WHO-I skull base meningiomas, with an acceptably low incidence of neurological deficits. KPS at the time of radiosurgery serves as a reliable long-term predictor of overall outcome.

Background: Training of surgical residents based on the traditional Halstedian model is becoming increasingly scrutinized. The emergence of competency-based training has put pressure on training programs to provide high-fidelity simulation sessions that compliment residents’ training in the operating room. Here we present a novel combination of perfused cadaveric avian wing model in conjunction with live rats for neurosurgical resident training. Methods: The brachial artery of cadaveric duck wing was cannulated and connected to a roller pump. The duck wings remain perfused while residents performed microvascular anastomoses of the brachial and ulnar arteries. This took place prior to live rat modules. Results: The duck wing brachial artery diameter measured 1.5-2.0 mm, similar to the proximal middle cerebral artery in humans. The ulnar artery diameter measured 1.0-1.5 mm, similar to the cortical vessels. 8 interrupted stitches were placed during anastomosis using a 10-0 Nylon suture. Residents who performed the duck wing module felt more comfortable when they moved onto the live rat model with a shallower learning curve. Conclusions: The perfused cadaveric avian wing model provides intermediate to high fidelity simulation that complements the live rat model well. The number of rats needed for neurosurgical simulation training could be reduced via the use of avian wings.

Background: The Canadian Neurosurgery Research Collaborative (CNRC) is a new consortium of neurosurgery residency programs set-up to facilitate the planning and implementation of multi-center studies. As a trainee-led organization, it will focus on resident-initiated, resident-driven projects. The goal of this study is to assess the demographics of Canadian neurosurgery residents, with particular focus on their academic and subspecialty interests. Methods: After approval by the CNRC, an online survey will be sent to all Canadian neurosurgery residents and fellows with reminders at 2, 4 and 6 weeks. Anonymous, basic demographic data will be collected. Specific interest towards the various subspecialties, research and academic vs community practice will be measured. The data will be crossed with the ongoing Canadian Neurosurgery Operative Landscape study to assess the impact of case volume on academic and subspecialty interests. Results: This is the first study providing a snapshot of Canadian neurosurgery residents at all levels of training. The study is ongoing and the official results will be presented at the meeting. As one of the first CNRC studies, it will also demonstrate the effectiveness of the collaborative. Conclusions: Understanding the demographics and interests of Canadian neurosurgery residents will allow the CNRC to better fulfill its mission.

For patient with a recurrent or residual acromegaly or Cushing’s disease (CD) after resection, Gamma knife radiosurgery (GKRS) is often used. Hypopituitarism is the most common adverse effect after GKRS treatment. The paucity of studies with long-term follow up has hampered understanding of the latent risks of hypopituitarism in patients with a Acromegaly or CD. We report the long-term risks of hypopituitarism for patients treated with GKRS for Acromegaly or CD. Methods: From a prospectively created, IRB approved database, we identified all patients with a Acromegaly or CD treated with GKRS at the University of Virginia from 1989 to 2008. Only patients with a minimum endocrine follow up of 60 months were included. The median follow-up is 159.5 months (60.1-278). Thorough radiological and endocrine assessments were performed immediately before GKRS and at regular follow-up intervals. New onset of hypopituitarism was defined as pituitary hormone deficits after GKRS requiring corresponding hormone replacement. Results: 60 patients with either Acromegaly or CD were included. Median tumor volume at time of GKRS was 1.3 cm3 (0.3-13.4), median margin dose was 25 Gy (6-30). GKRS induced new pituitary deficiency occurred in 58.3% (n=35) of patients. Growth Hormone deficiency was most common (28.3%, n=17). The actuarial overall rates of hypopituitarism at 3, 5, and 10 years were 10%, 21.7%, and 53.3%, respectively. The median time to hypopituitarism was 61 months after GKRS (range, 12-160). Cavernous sinus invasion of the tumor was found to correlate with the occurrence of a new or progressive hypopituitarism after GKRS (p=0.018). Conclusions: Delayed hypopituitarism increases as a function of time after radiosurgery. Hormone axes appear to vary in terms of radiosensitivity. Patients with adenoma in the cavernous sinus are more prone to develop loss of pituitary function after GKRS.

Subependymal giant cell astrocytoma (SEGA) is typically seen in children with tuberous sclerosis (TS), who present with headaches and seizures, and characteristic clinical and cutaneous manifestations of TS. Surgical resection, CSF diversion (for hydrocephalus), radiotherapy, and chemotherapy with a mammalian target of rapamycin (mTOR) inhibitor are treatment options. SEGA can occur in adults without TS, raising diagnostic and therapeutic challenges. A 53 year old man presented with headaches and diplopia. An exophytic, enhancing mass in the left lateral ventricle was resected, confirming SEGA. There was no recurrence on MRI 13 months later. He previously had an “astrocytoma” involving the left frontal horn resected at age 19. Pathology review was SEGA. He had no clinical or cutaneous findings of TS, and no family history of TS. An identical twin was well. A 66 year old man presented with “weakness”, due to diuretic-induced hypokalemia. CT showed a hypodense mass from the right caudate head deforming the frontal horn. MRI showed an exophytic, enhancing mass from the caudate head into the frontal horn. A stereotactic biopsy confirmed SEGA. He had no clinical or cutaneous findings of TS, and negative family history. His mother had a meningioma resected at age 66. Observation is planned. These 2 adult patients had SEGA without clear clinical findings or family history of TS. SEGA should be in the differential diagnosis of tumors involving the lateral ventricle.

Background: Current selection methods for neurosurgical residents lack objective measurements of psychomotor performance. This pilot study was designed to answer three questions: 1) What are the differences in bimanual psychomotor performance among neurosurgical residency applicants using the NeuroVR (formerly NeuroTouch) neurosurgical simulator? 2) Are there exceptionally skilled medical student applicants? 3) Does previous surgical exposure influence surgical performance? Methods: Medical students attending neurosurgery residency interviews at McGill University were asked to participate. Participants were instructed to remove 3 simulated brain tumors. Validated tier 1, tier 2, and advanced tier 2 metrics were utilized to assess bimanual psychomotor performance. Demographic data included weeks of neurosurgical elective and prior operative exposure. Results: Sixteen of 17 neurosurgical applicants (94%) participated. Performances clustered in definable top, middle, and bottom groups with significant differences for all metrics. Increased time spent playing music, increase applicant self-evaluated technical skills, high self-ratings of confidence and increased skin closures statistically influenced performance on univariate analysis. A trend for both self-rated increased operating room confidence and increased weeks of neurosurgical exposure to increase blood loss was seen in multivariate analysis. Conclusions: Simulation technology identifies neurosurgical residency applicants at the extremes of technical ability and extrinsic and intrinsic applicant factors appear to influence performance.

Plasmacytomas are solitary tumours characterized by neoplastic proliferation of plasma cells and can be found isolated or in associated with multiple myeloma. Plasmacytomas uncommonly occur intracranially, and dural plasmacytomas without involvement of the calvarium are exceedingly rare. Reported cases indicate durally-based plasmacytomas mimick the appearance of meningioma, lymphoma or sarcoma of the dura. The authors report a case of a 77-year-old male with known multiple myeloma who presented with a 3-week history of confusion, speech impediment, and right sided weakness. A non-contrast CT scan revealed a dense extra-axial mass in the left frontal lobe with initial concerns of an extra-axial hemorrhage. A subsequent MRI demonstrated a contrast enhancing mass with a broad-based dural tail and no underlying calvarial lesion. Differential diagnosis included meningioma or intracranial plasmacytoma. The patient underwent surgical resection and was found to have intratumoural hemorrhage, with pathology confirming plasmacytoma. In the published literature, there are only 20 prior reports of dural plasmacytomas (with and without primary calvarial infiltration), of which only five previous cases reported associated intratumoural hemorrhage. Our case, along with this literature, suggests that new onset of focal neurologic deficits in patients with a history of multiple myeloma merits careful investigation, and that intracranial plasmacytoma should be considered on the differential diagnosis even when imaging reveals masses consistent with hemorrhage or meningioma.

Background: Anticholinergic and sedating medications are generally contraindicated in those with cognitive decline. We examined trends in medication use by patients presenting to a rural and remote memory clinic (RRMC) between March 2004 and June 2015 to determine whether patterns of medication use have changed. Methods: The first 445 patients seen at the RRMC between 2004 and 2015 were included in this analysis. Medication lists were collected at the patient’s initial visit, and it was noted whether patients were taking anticholinergic or potentially sedating drugs. Statistical analysis (Spearman’s Correlation) was conducted to examine trends in medication use over time. Results: Ninety-one patients (20.5%) were taking at least one anticholinergic medication. There was a statistically significant decline (25.0% in 2004 to 12.5% in 2014) in percentage of patients presenting with anticholinergic medications over the eleven years of this study (Spearman’s correlation coefficient=-0.64, p=0.035). Conclusions: The most encouraging statistic to come from this study is a decline in anticholinergic medication use in this rural population. Prescribers must be properly informed to ensure that the number of medications per patient does not continue to rise, that medications are used only as necessary, and that potentially deleterious medications are avoided.

Background: Septo-Optic Dysplasia is a rare disorder with developmental malformations that was first reported by De Morsier.SOD associated with refractory epilepsy has not been well studied. We report six cases with SOD in patients with malformation of cortical development(MCD) and medically refractory epilepsy that underwent video-EEG telemetry. Methods: Six cases of SOD plus were admitted to the Epilepsy Monitoring Unit at London Health Sciences Centre because of medically refractory epilepsy. Functional hemispherectomy in one patient resulted in significant reduction of her seizures while insertion of a vagus nerve stimulator was not successful in controlling seizures in another patient. Right temporal resection for one patient resulted in about 60% reduction in her seizures. The remaining three patients were not surgical candidates and they remained on antiepileptic drugs. Results: MCD was present in 4/6 patients. Bilateral optic nerve hypoplasia was found in 50% of the patients. EEG was abnormal in all cases(6/6).Intractable epilepsy was found in 6/6 patients. Conclusions: SOD plus was associated with medically refractory epilepsy.

Traditional and advanced magnetic resonance imaging techniques are often unable to differentiate progressive central nervous system neoplasm from post-treatment radiation effect (PTRE). 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) with delayed imaging has been shown to increase the specificity of PET imaging for cerebral neoplasm in small studies. We sought to further evaluate the potential diagnostic benefits of delayed imaging at 5 hours versus standard imaging at 1 hour to differentiate progressive disease (PD) from PTRE in patients with primary or metastatic brain tumors treated with radiation therapy.

Ten patients with primary (n=4) and metastatic (n=6) brain tumors were identified, with diagnostic confirmation of PD or PTRE provided by pathology or>3 month clinical and radiographic follow-up. Maximum standard uptake values (SUV) were calculated for suspicious areas of abnormal contrast enhancement (lesion) and compared to contralateral normal appearing brain (background) at both early and delayed time points. Seven patients were classified as having PD and 3 as having PTRE based pathology or clinical/radiographic follow up. The average lesion to background ratio (L/B) at the early time point (1.16+0.50) was significantly different than L/B for the later time point (1.72+1.10), p=0.030. The mean L/B for PD was 2.17+1.01 at the later time point compared to 0.65+0.06 for PTRE (p=0.010). For the earlier time point, L/B for PD was 1.40+0.42, compared to the L/B for PTRE which was 0.61+0.10 (p=0.003).L/B ratios at early and delayed time points successfully differentiated between patients with PD and PTRE, with significantly greater L/B ratios seen at delayed time points. These initial results are promising and further investigation is underway to evaluate the contribution of delayed imaging in differentiating PD from PTRE.

Background: Regulation of drivers licences aims to strike a balance between autonomy and public safety. In Newfoundland and Labrador, an individual experiencing seizures must have a 6-month seizure-free interval before a driving licence is reinstated, although exceptions apply. There is a paucity of data surrounding driving safety in people with epilepsy. Methods: The Department of Motor Vehicles and Registration extracted data from the charts of drivers experiencing seizures for the period between 2010-2014, inclusive. Two groups were examined: drivers aged 16-24 (n=104) and 75+ (n=115). Given that mandatory reporting is required in Newfoundland and Labrador, this theoretically represents a population-based study. Results: Overall, 5.1% of the population experienced a motor vehicle collision, and collisions were more frequent among younger drivers. Significantly more people in the 75+ category had a medical history that could have contributed to seizures. Only 37.6% of the overall sample had their first seizure reported. This was not different between age groups or seizure types (generalized vs. focal). Though the age groups differed with respect to seizure type, this did not affect driving safety, as measured by motor vehicle collisions and driving disobedience. Conclusions: We found a high rate of driving disobedience despite the requirement for mandatory reporting and seizure type did not affect driving safety.

Background: About 35% of patients with epilepsy may develop drug-resistant epilepsy (DRE). Identifying risk factors associated with DRE will allow us to identify earlier patients in the course of the disease. Methods: This is a case-control study nested within a cohort. Chart reviews of subjects who full fill inclusion criteria were completed. Inclusion criteria included age>18 years, focal epilepsy determined by clinical correlation and EEG. DRE was determined by ILAE criteria. Results: 149 subjects were included. Seventy had DRE (cases), and seventy-nine did not have DRE (controls). DRE group had a mean age of 41 years (SD+14.8) compared to the control group (49+17.5) (p=0.003). DRE group had a mean age at diagnosis of epilepsy of 19+15.3 compared to the control group with a mean of 33.6+21. (p=<0.001). The main risk factors identified in this study were; cortical dysplasia OR 8.67 (CI 1.04-72.3, p=0.026); mesial temporal sclerosis (MTS) (OR 2.69; CI 1.12-6.47; p=0.024); and presence of complex partial seizures (OR 2.04. Conclusions: Young age at diagnosis of focal epilepsy, diagnosis of cortical dysplasia, MTS, and presence of complex partial seizures are risk factors for DRE

Background: Polymicrogyria (PMG), a malformation of cortical development, describes an area of cerebral cortex with excessively small convolutions. This study examines the clinical spectrum of epilepsy associated with PMG, a condition which commonly presents as medically-refractory epilepsy. Methods: All patients investigated in the Epilepsy Monitoring Unit from 2006 to 2015 at our centre and identified to have PMG by MRI were studied by retrospective chart review. Results: We identified 8 patients (4 male), mean age 33 years (range: 28 to 46). Seven had childhood onset of epilepsy. All experienced focal-onset seizures; 6 had occasional evolution to generalized, bilaterally convulsive seizures. PMG was associated with schizencephaly in 3 cases. Five patients were investigated with intracranial electrodes. Two patients underwent resective surgery, 1 achieved seizure-freedom, and 1 had class III (ILAE classification) following parietal corticectomy. Two patients underwent placement of vagus nerve stimulation and one a stimulator of the anterior nuclei of the thalami. Conclusions: Medically-refractory cases of PMG should be considered for presurgical evaluation, despite only a small portion being amenable to resective surgery. Extensive cortical malformation on MRI made intracranial electrodes necessary to identify the epileptic zone. Epilepsy surgery remains an important consideration given the possibility of seizure-freedom, as achieved in our patient.

Background: SIRPIDS were first described in 2004 in patients admitted in an intensive care unit. Despite few studies attempting to better characterize SIRPIDS, their pathophysiology and clinical implication remain uncertain. Methods: Adult patients hospitalized in an intensive care unit with alteration of consciousness who underwent EEG recording in three separate centers were included in this retrospective study. Demographic data and EEG findings were noted. Characteristics of SIRPIDS were documented. The main outcome measures included the incidence of SIRPIDS, association of SIRPIDS with mortality and other EEG characteristics, EEG and clinical predictors of mortality. Results: 416 patients were included and SIRPIDs were identified in 43 patients (10.3%). The proportion of patients with SIRPIDs was not significantly different across the three sites (p=0.3351). Anoxia (p=0.0009), antiepileptic medications (p=0.0109), electrographic seizures (p=0.0259), triphasic waves (p=0.0012) and epileptiform discharges (p=0.0242) were independently associated with the presence of SIRPIDs. Older age (p=0.0050), anoxia (p=<0.0001) and absence of EEG reactivity (p<0.0001), but not SIRPIDs (p=0.1668), were independently associated with in-hospital mortality. Conclusions: In critically ill patients undergoing EEG, SIRPIDs occurred in 10% and were associated with other electrographic abnormalities previously reported to indicate poor prognosis. SIRPIDs were not independently associated with in-hospital mortality.

Background: Deep brain stimulation for epilepsy is becoming an effective option for the treatment of refractory epilepsy. This is the case of a 19-year-old male patient who has had refractory seizures since 2.5 years old. Seizures occur up to 100 times per day, including gelastic, complex partial, and generalized tonic-clonic types. Methods: Continuous video-EEG monitoring, technetium 99 m ECD SPECT, PET-CT and 3T MRI are used for localization. Depth electrodes are implanted in right frontal orbital, cingulate and lateral frontal regions. Results: Video-EEG records 79 seizures arising from the right frontocentral region. Clinically, patient assumes a fencing posture, with left arm extension. Some seizures undergo secondary generalization. SPECT reveals subtle asymmetric hyperperfusion in right mesial frontal area, while PET-CT and MRI do not show focal lesion(s).Stereo-EEG recording and stimulation confirm seizure onset and trigger zone in the premotor cingulate posterior region. Treatment with stimulation in this region at 130-150 Hz, 4-5 mA, and pulse duration 0.1 ms reduces seizure frequency from 100/day to 3/week. Seizures last only 2-3 seconds, without postictal confusion leading to improvements in neuropsychological function. AED dosages are not reduced. Conclusions: Successful intracranial EEG localization of otherwise non-lesional non-resectable seizure focus permits the use of deep brain stimulation that effectively reduces refractory seizure frequency.

Background: The clinical identification of hippocampal sclerosis (HS) is important in predicting surgical outcomes in patients with temporal lobe epilepsy (TLE). In cases where gross hippocampal sclerosis is not identifiable clinically, a more detailed analysis of hippocampal subfields using ultra-high-field magnetic resonance imaging (MRI) may reveal areas of abnormality, which was the focus of our study. Methods: Patients (N=13) with drug-resistant TLE (9 no-HS, 4 HS) and 20 age-matched healthy controls were scanned and compared using a 7T MRI protocol. Using a manual segmentation scheme to delineate hippocampal subfields, subfield-specific volume changes were studied between the two groups. In addition, radiological patient assessment at 7T was correlated with measured subfield changes. Results: Volumetry of the hippocampus at 7T in HS patients revealed significant ipsilateral subfield losses in CA1 and CA4DG. Volumetry also uncovered subfield volume losses in 33% of no-HS patients, which had not been detected conventionally. Furthermore, 89% of no-HS patients showed abnormality (internal architecture or size) at 7T, identified by radiologists blinded to the patient’s initial classification. Conclusions: These preliminary findings indicate that hippocampal subfield volumetry assessed at 7T may be superior to conventional visual inspection by a neuroradiologist in the identification of hippocampal pathologies in TLE.

Background: Seizures and epilepsy are well-recognized complications after stroke. However, the reported incidence varies and so does their management. Methods: We conducted a systematic review and sought observational studies that reported incidence of seizures and/or epilepsy following arterial ischemic stroke in adults, and those that reported the management of epilepsy, specifically the use of EEG to determine the diagnosis, timing of initiation of anti-epileptic drug (AED), and the treatment response to AEDs. We systematically searched in Medline including Pre-Medline and EMBASE databases from their inception to October 1, 2015. First the titles and then the articles were reviewed and rated by two independent reviewers, and disagreements were resolved by consultation with a third reviewer. A pre-set data abstraction form was used for extracting the information of interest. Results: A total of 11,815 titles were found from the initial search strategy across all databases following de-duplication. Of these 130 studies are included for full text review. The adjudication process is underway and the reviewers are sifting through these studies to select the studies that will be included in the final review. Conclusions: Understanding incidence and management of post-stroke epilepsy is important to improve the quality of life of stroke survivors.

Background: Bilateral facial paralysis is a rare manifestation of Human Immunodeficiency Virus (HIV). Few cases of HIV seroconversion syndrome presenting with aseptic meningitis and facial diplegia have been previously reported. Methods: Case Report. Case Description: A 44-year-old male with uncontrolled hypertension who presented with 5-day history of migrainous headache, bucco-labial dysarthria, meningismus and dysguesia. Three weeks prior to presentation, he suffered a transient febrile illness preceded by an unprotected sexual encounter while vacationing in Côte d’Ivoire. Examination was significant for hypertensive urgency, bilateral lower motor neuron (LMN) facial paralysis, and meningeal irritation. Investigations revealed acute on chronic renal impairment and left ventricular hypertrophy. Brain MRI (without contrast) revealed microhemorrhages with dystrophic calcifications and microangiopathic changes. CSF analysis revealed 55 WBC (lymphocytic), normal glucose, and 0.67g/L protein. The infectious work-up was positive for HIV, which was confirmed by Western Blot (WB). CD4 count was 176 cells/μL and the viral load was 419,289 copies/ml. Lyme antibodies were also positive by enzyme-linked immunosorbent assay (ELISA), but negative by WB. Discussion: Facial diplegia is a rare manifestation of HIV, and can be indicative of a seroconversion syndrome. This case illustrates another layer of complexity; deciphering acute from chronic systemic manifestations of hypertension, and appreciating falsely positive Lyme antibodies by ELISA during acute HIV seroconversion.