Reid C Thompson

SickKids, Toronto, Ontario, Canada

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Publications (134)

  • [Show abstract] [Hide abstract] ABSTRACT: Background: Mass cytometry measures 36 or more markers per cell and is an appealing platform for comprehensive phenotyping of cells in human tissue and tumor biopsies. While tissue disaggregation and fluorescence cytometry protocols were pioneered decades ago, it is not known whether established protocols will be effective for mass cytometry and maintain cancer and stromal cell diversity. Methods: Tissue preparation techniques were systematically compared for gliomas and melanomas, patient derived xenografts of small cell lung cancer, and tonsil tissue as a control. Enzymes assessed included DNase, HyQTase, TrypLE, collagenase (Col) II, Col IV, Col V, and Col XI. Fluorescence and mass cytometry were used to track cell subset abundance following different enzyme combinations and treatment times. Results: Mechanical disaggregation paired with enzymatic dissociation by Col II, Col IV, Col V, or Col XI plus DNase for 1 hour produced the highest yield of viable cells per gram of tissue. Longer dissociation times led to increasing cell death and disproportionate loss of cell subsets. Key markers for establishing cell identity included CD45, CD3, CD4, CD8, CD19, CD64, HLA-DR, CD11c, CD56, CD44, GFAP, S100B, SOX2, nestin, vimentin, cytokeratin, and CD31. Mass and fluorescence cytometry identified comparable frequencies of cancer cell subsets, leukocytes, and endothelial cells in glioma (R = 0.97), and tonsil (R = 0.98). Conclusions: This investigation establishes standard procedures for preparing viable single cell suspensions that preserve the cellular diversity of human tissue microenvironments. This article is protected by copyright. All rights reserved.
    Article · Sep 2016 · Cytometry Part B Clinical Cytometry
  • [Show abstract] [Hide abstract] ABSTRACT: Objective: To characterize the risk and predictors of growth during observation of vestibular schwannomas (VS). Study design: Retrospective case series. Setting: Single academic, tertiary care center. Patients: Five hundred sixty-four consecutive VS patients who underwent at least two magnetic resonance imaging (MRI) studies before intervention. Intervention(s): Serial MRI studies. Main outcome measure(s): Tumor growth, defined as a ?2?mm increase in the maximum tumor diameter between consecutive MRI studies, or between the first and last study. Results: A total of 1296 patients (1995-2015) with VS were identified. Of those, 564 patients (median age 59.2 years; 53.5% female) were initially observed and underwent multiple MRI studies (median follow-up 22.9 months, interquartile range [IQR] 11.7-42.7). The median maximum tumor diameter at presentation was 1.00?cm (IQR 0.6-1.51?cm). In all, 40.8% of tumors demonstrated growth and 32.1% underwent intervention (21.5% microsurgery, 10.5% radiation) during the surveillance period. Multivariable Cox regression analysis showed that for each tumor, the risk of growth or intervention was significantly increased for larger initial VS diameters (HR?=?2.22; 95% CI: 1.90-2.61) and when disequilibrium was a presenting symptom (HR?=?1.70; 95% CI: 1.30-2.23). Patient age, sex, aspirin use, and presenting symptoms of asymmetric hearing loss, tinnitus, and vertigo were not associated with tumor growth. Conclusion: To date, this is the largest series of observed VS reported in the literature. Risk of VS growth is significantly increased among patients who present with larger tumors and who have concomitant disequilibrium. IRB:: 151481. Define professional practice gap and educational need: No cohort with this sample size has assessed vestibular schwannoma growth rates in conjunction with this number of variables. Learning objective: To characterize vestibular schwannoma growth rates and predictors of growth.
    Article · Sep 2016 · Otology & Neurotology
  • [Show abstract] [Hide abstract] ABSTRACT: The ventricular-subventricular zone (V-SVZ), which lies in the walls of the lateral ventricles (LV), is the largest neurogenic niche within the adult brain. Whether radiographic contact with the LV influences survival in glioblastoma (GBM) patients remains unclear. We assimilated and analyzed published data comparing survival in GBM patients with (LV+GBM) and without (LV-GBM) radiographic LV contact. PubMed, EMBASE, and Cochrane electronic databases were searched. Fifteen studies with survival data on LV+GBM and LV-GBM patients were identified. Their Kaplan–Meier survival curves were digitized and pooled for generation of median overall (OS) and progression free (PFS) survivals and log-rank hazard ratios (HRs). The log-rank and reported multivariate HRs after accounting for the common predictors of GBM survival were analyzed separately by meta-analyses. The calculated median survivals (months) from pooled data were 12.95 and 16.58 (OS), and 4.54 and 6.25 (PFS) for LV+GBMs and LV-GBMs, respectively, with an overall log-rank HRs of 1.335 [1.204–1.513] (OS) and 1.387 [1.225–1.602] (PFS). Meta-analysis of log-rank HRs resulted in summary HRs of 1.58 [1.35–1.85] (OS, 10 studies) and 1.41 [1.22–1.64] (PFS, 5 studies). Meta-analysis of multivariate HRs resulted in summary HRs of 1.35 [1.14–1.58] (OS, 6 studies) and 1.64 [0.88–3.05] (PFS, 3 studies). Patients with GBM contacting the LV have lower survival. This effect may be independent of the common predictors of GBM survival, suggesting a clinical influence of V-SVZ contact on GBM biology.
    Article · Sep 2016 · Journal of Neuro-Oncology
  • [Show abstract] [Hide abstract] ABSTRACT: Objectives: In recent years, there has been increased recognition of the relationship between type 2 diabetes mellitus (DM) and poor outcomes following a variety of surgical procedures. We sought to study the role of type 2 DM as a prognostic factor affecting the long-term survival of patients undergoing surgical resection of a WHO Grade I meningioma. Methods: We conducted a retrospective cohort study on 196 patients who had a WHO Grade I meningioma resected at our institution between 2001 and 2013. The medical record was reviewed to identify a pre-existing diagnosis of type 2 DM. Patient mortality was reviewed by medical record and Social Security Death Index (SSDI). Variables associated with survival in a univariate analysis were included in the multivariate Cox model if P<0.10. Variables with probability values >0.05 were then removed from the multivariate model in a step-wise fashion. Results: 33 (17%) patients had pre-existing diagnoses of type 2 DM prior to clinical presentation. Mean survival time in diabetic patients was 52.1 months compared to 160.9 months in non-diabetics. The decreased survival rate and time in patients with type 2 DM were found to be statistically significant (p=0.008 and p<0.0001, respectively). In a multivariate Cox analysis, a pre-existing history of type 2 DM was independently associated with decreased survival following the resection of a WHO Grade I meningioma (HR=2.6, p=0.045). Conclusions: A pre-existing diagnosis of type 2 DM is an independent negative prognostic indicator following the resection of a WHO Grade I meningioma.
    Article · Jul 2016 · Clinical neurology and neurosurgery
  • [Show abstract] [Hide abstract] ABSTRACT: OBJECTIVE Antiepileptic drugs (AEDs) are often administered prophylactically following brain tumor resection. With conflicting evidence and unestablished guidelines, however, the nature of this practice among tumor surgeons is unknown. METHODS On November 24, 2015, a REDCap (Research Electronic Database Capture) survey was sent to members of the AANS/CNS Section on Tumors to query practice patterns. RESULTS Responses were received from 144 individuals, including 18.8% of board-certified neurosurgeons surveyed (across 86 institutions, 16 countries, and 5 continents). The majority reported practicing in an academic setting (85%) as a tumor specialist (71%). Sixty-three percent reported always or almost always prescribing AED prophylaxis postoperatively in patients with a supratentorial brain tumor without a prior seizure history. Meanwhile, 9% prescribed occasionally and 28% rarely prescribed AED prophylaxis. The most common agent was levetiracetam (85%). The duration of seizure prophylaxis varied widely: 25% of surgeons administered prophylaxis for 7 days, 16% for 2 weeks, 21% for 2 to 6 weeks, and 13% for longer than 6 weeks. Most surgeons (61%) believed that tumor pathology influences epileptogenicity, with high-grade glioma (39%), low-grade glioma (31%), and metastases (24%) carrying the greatest seizure risk. While the majority used prophylaxis, 62% did not believe or were unsure if prophylactic AEDs reduced seizures postoperatively. The vast majority (82%) stated that a well-designed randomized trial would help guide their future clinical decision making. CONCLUSIONS Wide knowledge and practice gaps exist regarding the frequency, duration, and setting of AED prophylaxis for seizure-naive patients undergoing brain tumor resection. Acceptance of universal practice guidelines on this topic is unlikely until higher-level evidence supporting or refuting the value of modern seizure prophylaxis is demonstrated.
    Article · Jun 2016 · Journal of Neurosurgery
  • [Show abstract] [Hide abstract] ABSTRACT: OBJECTIVE:: To analyze disease presentation, treatment, and clinical course of a consecutive series of patients with primary cerebellopontine angle (CPA) epidermoids. PATIENTS:: Forty-seven consecutive patients with previously untreated CPA epidermoids. INTERVENTION(S):: Observation and microsurgery. MAIN OUTCOME MEASURES:: Disease- and treatment-associated morbidity, recurrence. RESULTS:: Forty-seven patients (mean age 39 years; 53% women) were analyzed and the average duration of follow-up was 42 months. The most common presenting symptom was headache (27; 57%); 13 (28%) exhibited preoperative asymmetric sensorineural hearing loss, 3 (6%) facial nerve paresis, and 3 (6%) hemifacial spasm. Thirteen patients (28%) were initially observed over a mean interval of 56 months; however, five experienced disease progression requiring operation. Thirty-nine patients (83%) underwent surgical resection; 18 (46%) received gross total, 5 (13%) near total, and 16 (41%) aggressive subtotal resection. Three patients (8%) recurred at a median of 53 months; two after subtotal and one after gross total resection. Ninety-three percent of patients with useful hearing maintained serviceable hearing following treatment and one patient (3%) experienced mild long-term postoperative facial nerve paresis (HB II/VI). All patients with preoperative facial nerve paresis recovered normal function postoperatively. There were no episodes of stroke or death. CONCLUSIONS:: Surgical intervention is effective in alleviating symptoms of cranial neuropathy and brainstem compression from CPA epidermoids. Gross total resection is preferred; however, aggressive subtotal removal should be considered with adherent or extensive disease as reoperation rates are low, even in the setting of aggressive subtotal resection. Conservative observation with serial imaging is a viable initial strategy in asymptomatic or minimally symptomatic patients. Copyright © 2016 by Otology & Neurotology, Inc. Image
    Article · Jun 2016 · Otology & Neurotology
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    Full-text Article · Jun 2016 · Otology & Neurotology
  • [Show abstract] [Hide abstract] ABSTRACT: Marginal zone B-cell lymphoma of the meninges is a rare pathological subtype of central nervous system lymphoma that can mimic the radiologic appearance of meningioma. We present a unique case of a 57-year-old male who presented with neurologic symptoms of severe headache, memory loss, mental status changes, and depression. Subsequent magnetic resonance imaging of the brain demonstrated an enhancing mass tracking along the anterior falx and anterior skull base with extension into the ethmoid sinus, which was radiographically consistent with meningioma. However, pathologic examination revealed numerous sheets of plasma cells and plasmacytoid lymphocytes that were immunopositive for CD20. These combined features were indicative of marginal zone B-cell lymphoma. No evidence of systemic disease was found. While rare, marginal zone B-cell lymphoma must be considered in the differential diagnosis of an extra-axial enhancing mass. We review the contemporary literature and discuss pre-operative radiologic differentiation of these two very different histopathologies.
    Article · May 2016 · World Neurosurgery
  • Article · May 2016
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    Rohan Vijayan · Rebekah H. Conley · Reid C. Thompson · [...] · Michael I. Miga
    [Show abstract] [Hide abstract] ABSTRACT: Brain shift describes the deformation that the brain undergoes from mechanical and physiological effects typically during a neurosurgical or neurointerventional procedure. With respect to image guidance techniques, brain shift has been shown to compromise the fidelity of these approaches. In recent work, a computational pipeline has been developed to predict “brain shift” based on preoperatively determined surgical variables (such as head orientation), and subsequently correct preoperative images to more closely match the intraoperative state of the brain. However, a clinical workflow difficulty in the execution of this pipeline has been acquiring the surgical variables by the neurosurgeon prior to surgery. In order to simplify and expedite this process, an Android, Java-based application designed for tablets was developed to provide the neurosurgeon with the ability to orient 3D computer graphic models of the patient’s head, determine expected location and size of the craniotomy, and provide the trajectory into the tumor. These variables are exported for use as inputs for the biomechanical models of the preoperative computing phase for the brain shift correction pipeline. The accuracy of the application’s exported data was determined by comparing it to data acquired from the physical execution of the surgeon’s plan on a phantom head. Results indicated good overlap of craniotomy predictions, craniotomy centroid locations, and estimates of patient’s head orientation with respect to gravity. However, improvements in the app interface and mock surgical setup are needed to minimize error.
    Full-text Conference Paper · Mar 2016
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    [Show abstract] [Hide abstract] ABSTRACT: Brain shift compensation using computer modeling strategies is an important research area in the field of image-guided neurosurgery (IGNS). One important source of available sparse data during surgery to drive these frameworks is deformation tracking of the visible cortical surface. Possible methods to measure intra-operative cortical displacement include laser range scanners (LRS), which typically complicate the clinical workflow, and reconstruction of cortical surfaces from stereo pairs acquired with the operating microscopes. In this work, we propose and demonstrate a craniotomy simulation device that permits simulating realistic cortical displacements designed to measure and validate the proposed intra-operative cortical shift measurement systems. The device permits 3D deformations of a mock cortical surface which consists of a membrane made of a Dragon Skin® high performance silicone rubber on which vascular patterns are drawn. We then use this device to validate our stereo pair-based surface reconstruction system by comparing landmark positions and displacements measured with our systems to those positions and displacements as measured by a stylus tracked by a commercial optical system. Our results show a 1mm average difference in localization error and a 1.2mm average difference in displacement measurement. These results suggest that our stereo-pair technique is accurate enough for estimating intra-operative displacements in near real-time without affecting the surgical workflow.
    Full-text Conference Paper · Mar 2016
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    [Show abstract] [Hide abstract] ABSTRACT: Patients with incomplete surgical resection of medulloblastoma are controversially regarded as having a marker of high-risk disease, which leads to patients undergoing aggressive surgical resections, so-called second-look surgeries, and intensified chemoradiotherapy. All previous studies assessing the clinical importance of extent of resection have not accounted for molecular subgroup. We analysed the prognostic value of extent of resection in a subgroup-specific manner.
    Full-text Article · Mar 2016 · The Lancet Oncology
  • [Show abstract] [Hide abstract] ABSTRACT: OBJECTIVE Seizures are among the most common perioperative complications in patients undergoing craniotomy for brain tumor resection and have been associated with increased disease progression and decreased survival. Little evidence exists regarding the relationship between postoperative seizures and hospital quality measures, including length of stay (LOS), disposition, and readmission. The authors sought to address these questions by analyzing a glioma population over 15 years. METHODS A retrospective cohort study was used to evaluate the outcomes of patients who experienced a postoperative seizure. Patients with glioma who underwent craniotomy for resection between 1998 and 2013 were enrolled in the institutional tumor registry. Basic data, including demographics and comorbidities, were recorded in addition to hospitalization details and complications. Seizures were diagnosed by clinical examination, observation, and electroencephalography. The Student t-test and chi-square test were used to analyze differences in the means between continuous and categorical variables, respectively. Multivariate logistic and linear regression was used to compare multiple clinical variables against hospital quality metrics and survival figures, respectively. RESULTS In total, 342 patients with glioma underwent craniotomy for first-time resection. The mean age was 51.0 ± 17.3 years, 192 (56.1%) patients were male, and the median survival time for all grades was 15.4 months (range 6.2-24.0 months). High-grade glioma (Grade III or IV) was seen in 71.9% of patients. Perioperative antiepileptic drugs were administered to 88% of patients. Eighteen (5.3%) patients experienced a seizure within 14 days postoperatively, and 9 (50%) of these patients experienced first-time seizures. The mean time to the first postoperative seizure was 4.3 days (range 0-13 days). There was no significant association between tumor grade and the rate of perioperative seizure (Grade I, 0%; II, 7.0%; III, 6.1%; IV, 5.2%; p = 0.665). A single ictal episode occurred in 11 patients, while 3 patients experienced 2 seizures and 4 patients developed 3 or more seizures. Compared with their seizure-free counterparts, patients who experienced a perioperative seizure had an increased average hospital (6.8 vs 3.6 days, p = 0.032) and ICU LOS (5.4 vs 2.3 days; p < 0.041). Seventy-five percent of seizure-free patients were discharged home in comparison with 55.6% of seizure patients (p = 0.068). Patients with a postoperative seizure were significantly more likely to visit the emergency department within 90 days (44.4% vs 19.0%; OR 3.41 [95% CI 1.29-9.02], p = 0.009) and more likely to be readmitted within 90 days (50.0% vs 18.4%; OR 4.45 [95% CI 1.69-11.70], p = 0.001). In addition, seizure-free patients had a longer median overall survival (15.6 months [interquartile range 6.6-24.4 months] vs 3.0 months [interquartile range 1.0-25.0 months]; p = 0.013). CONCLUSIONS Patients with perioperative seizures following glioma resection required longer hospital and ICU LOS, were readmitted at higher rates than seizure-free patients, and experienced shorter overall survival. Biological and clinical factors that predispose to the development of seizures after glioma surgery portend a worse outcome. Efforts to identify these factors and reduce the risk of postoperative seizure should remain a priority among neurosurgical oncologists.
    Article · Feb 2016 · Journal of Neurosurgery
  • Kathleen M. Egan · Louis B. Nabors · Zachary J. Thompson · [...] · Reid C. Thompson
    [Show abstract] [Hide abstract] ABSTRACT: Glioma and meningioma are uncommon tumors of the brain with few known risk factors. Regular use of aspirin has been linked to a lower risk of gastrointestinal and other cancers, though evidence for an association with brain tumors is mixed. We examined the association of aspirin and other analgesics with the risk of glioma and meningioma in a large US case–control study. Cases were persons recently diagnosed with glioma or meningioma and treated at medical centers in the southeastern US. Controls were persons sampled from the same communities as the cases combined with friends and other associates of the cases. Information on past use of analgesics (aspirin, other anti-inflammatory agents, and acetaminophen) was collected in structured interviews. Logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for analgesic use adjusted for potential confounders. All associations were considered according to indication for use. A total of 1123 glioma cases, 310 meningioma cases and 1296 controls were included in the analysis. For indications other than headache, glioma cases were less likely than controls to report regular use of aspirin (OR 0.69; CI 0.56, 0.87), in a dose-dependent manner (P trend < 0.001). No significant associations were observed with other analgesics for glioma, or any class of pain reliever for meningioma. Results suggest that regular aspirin use may reduce incidence of glioma.
    Article · Feb 2016 · European Journal of Epidemiology
  • [Show abstract] [Hide abstract] ABSTRACT: The optimal timing and frequency of postoperative imaging surveillance after a meningioma resection are not well-established. The low recurrence rates and slow growth of World Health Organization (WHO) Grade I meningiomas in particular have raised doubts about the utility of postoperative imaging surveillance. We sought to analyze the cost and utility of asymptomatic surveillance imaging in elderly patients after the resection of a WHO Grade I meningioma. We conducted a retrospective cohort study on 45 patients who had a primary WHO Grade I meningioma resected at our institution between 2001-2013 at or above the age of 60 with a minimum of 2years of follow-up. All postoperative clinic notes were reviewed alongside imaging results to verify that patients were asymptomatic during the surveillance period. MRI and CT scan costs (all $USD) were estimated at $599.61 and $334.31 respectively based on the Centers for Medicare and Medicaid national averages. During an average follow-up period of 4.5years, the average number of total imaging studies performed per asymptomatic patient was 3.58 with an average total cost of $2086.30 per patient. Forty-two (93%) patients had no new abnormal findings on any of their imaging. Three (7%) patients demonstrated either a new meningioma or progressive growth of the postoperative residual tumor on imaging. No asymptomatic patient underwent a reoperation. Our data suggest that elderly patients with resected WHO Grade I meningiomas are at low risk for recurrence and may not need asymptomatic surveillance imaging for the first several postoperative years.
    Article · Dec 2015 · Journal of Clinical Neuroscience
  • [Show abstract] [Hide abstract] ABSTRACT: Previous authors have identified a number of factors that predict morbidity, mortality, and recurrence in patients undergoing resection of a meningioma. We sought to study a novel potential prognostic indicator: early postoperative visit to the emergency department (ED). We conducted a retrospective cohort study on 239 patients who underwent a meningioma resection at our institution between 2001 and 2013 with over 3months of follow-up postoperatively. All postoperative entries in the medical record were reviewed to identify any ED visit with a neurologic or wound-related complaint within a 90day postoperative period. The relationships between ED presentation, tumor grade, and extent of surgical resection with future risk of operative recurrence and mortality were analyzed using Fisher's exact test. Variables associated with increased risks of mortality or operative recurrence in a univariate analysis were then included in the multivariate logistic regression model. Patients with a postoperative ED visit were found to be significantly more likely to die during the follow-up period (23.0% versus 4.85%, p<0.0001) or develop an eventual operative recurrence (12.2% versus 3.0%, p=0.0131). Postoperative ED presentation was found to be associated with a higher risk of mortality and operative recurrence independent of pathological tumor grade (p<0.0001 and p=0.0102, respectively). Presentation to the ED is associated with significantly higher rates of future operative recurrence and mortality in patients with recent meningioma resections. This poor prognostic relationship is independent of tumor pathological grade. Increased vigilance and follow-up may be warranted in such patients.
    Article · Nov 2015 · Journal of Clinical Neuroscience
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    [Show abstract] [Hide abstract] ABSTRACT: Current positron emission tomography (PET) imaging biomarkers for detection of infiltrating gliomas are limited. Translocator protein (TSPO) is a novel and promising biomarker for glioma PET imaging. To validate TSPO as a potential target for molecular imaging of glioma, TSPO expression was assayed in a tumor microarray containing 37 high-grade (III, IV) gliomas. TSPO staining was detected in all tumor specimens. Subsequently, PET imaging was performed with an aryloxyanilide-based TSPO ligand, [18F]PBR06, in primary orthotopic xenograft models of WHO grade III and IV gliomas. Selective uptake of [18F]PBR06 in engrafted tumor was measured. Furthermore, PET imaging with [18F]PBR06 demonstrated infiltrative glioma growth that was undetectable by traditional magnetic resonance imaging (MRI). Preliminary PET with [18F]PBR06 demonstrated a preferential tumor-to-normal background ratio in comparison to 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG). These results suggest that TSPO PET imaging with such high-affinity radiotracers may represent a novel strategy to characterize distinct molecular features of glioma growth, as well as better define the extent of glioma infiltration for therapeutic purposes.
    Full-text Article · Oct 2015 · PLoS ONE
  • [Show abstract] [Hide abstract] ABSTRACT: Objectives To quantify the rates of loss of follow-up after meningioma resection and to identify any key demographical associations. Design Retrospective cohort. Setting Vanderbilt University Medical Center, 2001–2013. Participants A total of 281 patients surgically treated for an intracranial meningioma at a single institution between 2001 and 2013. Main Outcome Measures Patient clinical follow-up within the first postoperative year. Results A history of tobacco use (p < 0.0001), ongoing alcohol abuse at time of presentation (p = 0.0014), Medicaid coverage (p < 0.0001), and lack of a college degree (p < 0.0001) were all found to be predictors of loss of follow-up at a statistically significant level. Conclusions Several factors associated with low socioeconomic status are predictors of poor clinical follow-up after meningioma resection. The health risk of poor follow-up in this patient population is significant, and increased measures are needed to ensure regular appointment attendance.
    Article · Oct 2015 · Journal of Neurological Surgery, Part B: Skull Base
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    Michael I Miga · Kay Sun · Ishita Chen · [...] · Reid C Thompson
    [Show abstract] [Hide abstract] ABSTRACT: Purpose: Brain shift during neurosurgical procedures must be corrected for in order to reestablish accurate alignment for successful image-guided tumor resection. Sparse-data-driven biomechanical models that predict physiological brain shift by accounting for typical deformation-inducing events such as cerebrospinal fluid drainage, hyperosmotic drugs, swelling, retraction, resection, and tumor cavity collapse are an inexpensive solution. This study evaluated the robustness and accuracy of a biomechanical model-based brain shift correction system to assist with tumor resection surgery in 16 clinical cases. Methods: Preoperative computation involved the generation of a patient-specific finite element model of the brain and creation of an atlas of brain deformation solutions calculated using a distribution of boundary and deformation-inducing forcing conditions (e.g., sag, tissue contraction, and tissue swelling). The optimum brain shift solution was determined using an inverse problem approach which linearly combines solutions from the atlas to match the cortical surface deformation data collected intraoperatively. The computed deformations were then used to update the preoperative images for all 16 patients. Results: The mean brain shift measured ranged on average from 2.5 to 21.3 mm, and the biomechanical model-based correction system managed to account for the bulk of the brain shift, producing a mean corrected error ranging on average from 0.7 to 4.0 mm. Conclusions: Biomechanical models are an inexpensive means to assist intervention via correction for brain deformations that can compromise surgical navigation systems. To our knowledge, this study represents the most comprehensive clinical evaluation of a deformation correction pipeline for image-guided neurosurgery.
    Full-text Article · Oct 2015 · International Journal of Computer Assisted Radiology and Surgery
  • Scott L Zuckerman · Akshitkumar M Mistry · Rimal Hanif · [...] · Reid C Thompson
    [Show abstract] [Hide abstract] ABSTRACT: Purpose: Exposure to surgical sub-specialties is limited during the preclinical years of medical school. To offset this limitation, the authors created a Neurosurgery Elective for first and second year medical students. The objective was to provide each student with early exposure to neurosurgery by combining clinical experience with faculty discussions about the academic and personal realities of a career in neurosurgery. Methods: From 2012 to 2013, the authors offered a Neurosurgery Elective to first and second year medical students. Each class consisted of the following: 1) peer-reviewed article analysis; 2) student presentation; 3) faculty academic lecture; 4) faculty personal lecture with question and answer period. Results: Thirty-five students were enrolled over a two-year period. After completing the elective, students were more likely to: consider neurosurgery as a future career (p<0.0001), perceive the personalities of attendings to be more collegial and friendly (p=0.0002), perceive attending quality of life to be higher (p<0.0001), and feel it was achievable to be a neurosurgeon and have a family (p<0.0001). The elective did not alter students' perceived difficulty of training (p=0.7105). Conclusions: The Neurosurgery Elective significantly increased knowledge across several areas, changed perception about collegiality, quality of life, and family/work balance, while not altering the students' views about the difficulty of training. Adopting a neurosurgery elective can significantly change attitudes about the field of neurosurgery and has potential to increase interest in pursuing a career in neurosurgery.
    Article · Sep 2015 · World Neurosurgery

Publication Stats

2k Citations


  • 2012
    • SickKids
      Toronto, Ontario, Canada
  • 2010
    • San Diego Zoo
      San Diego, California, United States
  • 2001
    • University of California, Irvine
      Irvine, California, United States
  • 2000
    • University of North Carolina at Chapel Hill
      North Carolina, United States