Response to Preoperative Dexamethasone Predicts Postoperative Neurological Improvement of Focal Neurological Deficits in Patients With Brain Metastases

BACKGROUND

Steroids are used ubiquitously in the preoperative management of patients with brain tumor. The rate of improvement in focal deficits with steroids and the prognostic value of such a response are not known.

OBJECTIVE

To determine the rate at which focal neurological deficits respond to preoperative corticosteroids in patients with brain metastases and whether such an improvement could predict long-term recovery of neurological function after surgery.

METHODS

Patients with brain metastases and related deficits in language, visual field, or motor domains who received corticosteroids before surgery were identified. Characteristics between steroid responders and nonresponders were compared.

RESULTS

Ninety six patients demonstrated a visual field (13 patients), language (19), or motor (64) deficit and received dexamethasone in the week before surgery (average cumulative dose 43 mg; average duration 2.7 days). 38.5% of patients' deficits improved with steroids before surgery, while 82.3% of patients improved by follow-up. Motor deficits were more likely to improve both preoperatively ( P = .014) and postoperatively ( P = .010). All 37 responders remained improved at follow-up whereas 42 of 59 (71%) of nonresponders ultimately improved ( P < .001). All other clinical characteristics, including dose and duration, were similar between groups.

CONCLUSION

A response to steroids before surgery is highly predictive of long-term improvement postoperatively in brain metastasis patients with focal neurological deficits. Lack of a response portends a somewhat less favorable prognosis. Duration and intensity of therapy do not seem to affect the likelihood of response.

Innovative growth and development of a neurological surgery residency cadaveric skull base simulation training program: A single institution experience

OBJECTIVE

Neurosurgical cadaveric and simulation training is a valuable opportunity for residents and fellows to develop as neurosurgeons, further neuroanatomy knowledge, and develop decision-making and technical expertise. The authors describe the growth and development of Oregon Health & Science University (OHSU) Department of Neurological Surgery (NSG) resident hands-on simulation skull base course and provide details of course layout and setup.

METHODS

A three-part surgical simulation series was created to provide training in cadaveric skull base procedures. Course objectives were outlined for participants. Residents participated in NSG hands-on simulation courses (years 2015-2020) and completed annual course curriculum and anonymous course evaluations, which included free text reviews. Courses were evaluated by Likert scale analysis within Python, and free text was quantified using Valence Aware Dictionary for sEntiment Reasoning (VADER). Descriptive statistics were calculated and plotted using Python's Seaborn and Matplotlib library modules.

RESULTS

Analysis included 162 skull base (anterior fossa, middle fossa and lateral, and endoscopic endonasal-based) simulation course evaluations. Resident responses were overwhelmingly positive. Likert responses demonstrated high average responses for each question (4.62 ± 0.56 and above). A positive attitude about simulation courses is supported by an average compound sentiment value of 0.558 ± 0.285.

CONCLUSION

This is the first time Likert responses and sentiment analysis have been used to demonstrate how neurosurgical residents view a comprehensive, multi-year hands-on simulation training program. We hope the information presented serves as a guide for other institutions to develop their own residency educational curriculum in cadaveric skull base procedures.

Fluid dynamics in aging-related dementias

Recent human and animal model experimental studies revealed novel pathways for fluid movement, immune cell trafficking and metabolic waste clearance in CNS. These studies raise the intriguing possibility that the newly discovered pathways, including the glymphatic system, lymphatic meningeal vessels and skull-brain communication channels, are impaired in aging and neurovascular and neurodegenerative diseases associated with dementia, including Alzheimer's disease (AD) and AD-related dementia. We provide an overview of the glymphatic and dural meningeal lymphatic systems, review current methods and approaches used to study glymphatic flow in humans and animals, and discuss current evidence and controversies related to its role in CNS flow homeostasis under physiological and pathophysiological conditions. Non-invasive imaging approaches are needed to fully understand the mechanisms and pathways driving fluid movement in CNS and their roles across lifespan including healthy aging and aging-related dementia.

A technical note on anterolateral mobilization in vertebrobasilar dolichoectasia for relief of brainstem compression

Vascular compression of neural tissue causing neurological symptoms is a wellknown phenomenon. This is commonly seen in trigeminal neuralgia and, less commonly, in hemifacial spasm by small arteries, which can be treated by microvascular decompression. Rarely, larger arteries, such as the vertebral arteries, may compress the brainstem. This can lead to symptoms of pontine or medullary distress like hemiparesis, dysphagia, or respiratory distress. This is treated by macrovascular decompression. Due to the rare and heterogenous nature of this disease, there is no standardized approach. We describe a novel technique whereby the vertebrobasilar system is mobilized anterolaterally towards the occipital condyle with a sling to decompress the brainstem.

We report two cases of vertebrobasilar dolichoectasia causing brainstem compression. A carotid patch graft sling with anterolateral mobilization to the occipital condyle is described as a surgical nuance to macrovascular decompressive surgery. Briefly, the vertebral artery was identified and dissected away from the brainstem and the bulbar cranial nerves. Bovine pericardium graft was used to create a sling around the artery by suturing the two ends together. The sling was then fixed either to the occipital condyle using cranial plating screws or suturing to the dura of the occipital condyle.

A novel surgical technique for management of vertebrobasilar dolichoectasia causing brainstem compression with progressive neurological deterioration is reported. Anatomical location and the offending vessel should guide neurosurgeons to select the best surgical option to achieve complete decompression of the involved neural structures.

Regression of Multiple Meningiomas after Discontinuation of Chronic Hormone Therapy: A Case Report

Introduction  Meningiomas are more common in females and frequently express progesterone and estrogen receptors. Recent studies have revealed a high incidence of meningiomas in situations in which estrogen/progesterone levels are increased such as pregnancy, gender reassignment therapy, and fertility treatment. While the relationship remains unclear and controversial, these findings suggest exposure to high levels of endogenous or exogenous hormones may increase the risk of developing a meningioma.

Patients and Methods  A 40-year-old female with a history of endometriosis treated with chronic progesterone therapy presented with a visual deficit and was found to have multiple meningiomas, which regressed after cessation of exogenous progesterone.

Conclusion  A history of chronic hormone therapy should be included when evaluating patients diagnosed with meningiomas, particularly at a younger age and with multiple meningiomas. Cessation of exogenous progesterone resulting in regression of meningiomas suggests a direct action of progesterone on growth. Future studies are warranted to better elucidate this relationship.

Pituitary society expert Delphi consensus: operative workflow in endoscopic transsphenoidal pituitary adenoma resection

PURPOSE

Surgical workflow analysis seeks to systematically break down operations into hierarchal components. It facilitates education, training, and understanding of surgical variations. There are known educational demands and variations in surgical practice in endoscopic transsphenoidal approaches to pituitary adenomas. Through an iterative consensus process, we generated a surgical workflow reflective of contemporary surgical practice.

METHODS

A mixed-methods consensus process composed of a literature review and iterative Delphi surveys was carried out within the Pituitary Society. Each round of the survey was repeated until data saturation and > 90% consensus was reached.

RESULTS

There was a 100% response rate and no attrition across both Delphi rounds. Eighteen international expert panel members participated. An extensive workflow of 4 phases (nasal, sphenoid, sellar and closure) and 40 steps, with associated technical errors and adverse events, were agreed upon by 100% of panel members across rounds. Both core and case-specific or surgeon-specific variations in operative steps were captured.

CONCLUSIONS

Through an international expert panel consensus, a workflow for the performance of endoscopic transsphenoidal pituitary adenoma resection has been generated. This workflow captures a wide range of contemporary operative practice. The agreed "core" steps will serve as a foundation for education, training, assessment and technological development (e.g. models and simulators). The "optional" steps highlight areas of heterogeneity of practice that will benefit from further research (e.g. methods of skull base repair). Further adjustments could be made to increase applicability around the world.

Echocardiographic findings in acromegaly: prevalence of concentric left ventricular remodeling in a large single-center cohort

PURPOSE

Acromegaly is a rare disease and is associated with increased cardiovascular (CV) morbidity and mortality, especially in patients with uncontrolled disease. We aimed to analyze the prevalence and severity of cardiomyopathy and valvular heart disease in a large cohort of patients with a confirmed acromegaly diagnosis, at baseline and after treatment.

METHODS

We retrospectively reviewed an institutional approved database; 190 patients with confirmed acromegaly and follow-up data available (years 2006-2018). Patients with at least one baseline echocardiogram, were included. Demographic, disease control and echocardiogram variables were collected for analysis.

RESULTS

Of the 190 patients 110 (58%) had a baseline echocardiogram and 43 (39.1%) had at least one follow-up echocardiogram after surgical, medical or multimodal treatment. Baseline left ventricular hypertrophy (LVH) prevalence was 17.8% (64.7% concentric; 35.3% eccentric), diastolic and systolic dysfunction, and overt cardiomyopathy with heart failure were 15.8, 7.9, and 3.0%, respectively. Concentric remodeling of the left ventricle (LV) was noted in 31.4% of patients without LVH. Valve defects were found in 87.3% of patients (14.6% with significant valvular heart disease).

CONCLUSION

Early diagnosis of acromegaly and disease control should be attempted to prevent LVH/LV dysfunction and development of valvular heart disease. Concentric LV remodeling develops prior to obvious LV hypertrophy in almost a third of patients with acromegaly, which is a novel finding. Similar to other epidemiological studies, we found a high prevalence of LVH/LV dysfunction. Although possible, reversal of systolic and diastolic dysfunction is sporadic after treatment of acromegaly.

Determinants of survival in sinonasal and skull base chondrosarcoma: An analysis of the National Cancer Database

BACKGROUND

Chondrosarcomas are rare, malignant chondroid tumors that can occur in the sinonasal and skull base regions. Surgery is a mainstay of treatment, but complete resection can be challenging because of the close proximity of critical neurovascular structures. Because of their rarity and relatively indolent nature, optimal treatment regimens are not established. Our objective was to assess determinants of survival for sinonasal and skull base chondrosarcomas utilizing the National Cancer Database (NCDB).

METHODS

The NCDB (2004-2017) was queried for cases of sinonasal and skull base chondrosarcoma. Multivariate hazard regression modeling was used to identify significant predictors of 60-month and 120-month overall survival (OS).

RESULTS

Seven hundred thirty-six cases met inclusion criteria. OS for all treatment types was 84.7% [SE±0.02] at 60 months and 75.6% [SE±0.02] at 120 months. Surgery with or without adjuvant treatment was found to associate with highest OS at 60 and 120 months. For patients receiving adjuvant radiation during treatment, proton therapy had significantly better OS at 60 months (95.4% [SE±0.03] vs 82.3% [SE±0.03], -²  = 5.27; p = 0.02) and 120 months (85.1% [SE±0.08] vs 72.8% [SE±0.05], -²  = 4.11; p = 0.04) compared with conventional external beam. After adjustment for primary site, multivariate Cox regression modeling (n = 561) identified cofactors significantly associated with variation in mortality risk at 60 and 120 months, including age, Charlson-Deyo total score ≥ 3, insurance provision status, and tumor grade.

CONCLUSIONS

Sinonasal and skull base chondrosarcoma are primarily treated with surgery with favorable OS. Adjuvant treatment may be required and proton radiation was associated with improved 60-month and 120-month survival compared with conventional radiation.

In a model of SAH-induced neurogenic fever, BAT thermogenesis is mediated by erythrocytes and blocked by agonism of adenosine A1 receptors

Neurogenic fever (NF) after subarachnoid hemorrhage (SAH) is a major cause of morbidity that is associated with poor outcomes and prolonged stay in the neurointensive care unit (NICU). Though SAH is a much more common cause of fever than sepsis in the NICU, it is often a diagnosis of exclusion, requiring significant effort to rule out an infectious source. NF does not respond to standard anti-pyretic medications such as COX inhibitors, and lack of good medical therapy has led to the introduction of external cooling systems that have their own associated problems. In a rodent model of SAH, we measured the effects of injecting whole blood, blood plasma, or erythrocytes on the sympathetic nerve activity to brown adipose tissue and on febrile thermogenesis. We demonstrate that following SAH the acute activation of brown adipose tissue leading to NF, is not dependent on PGE₂, that subarachnoid space injection of whole blood or erythrocytes, but not plasma alone, is sufficient to trigger brown adipose tissue thermogenesis, and that activation of adenosine A1 receptors in the CNS can block the brown adipose tissue thermogenic component contributing to NF after SAH. These findings point to a distinct thermogenic mechanism for generating NF, compared to those due to infectious causes, and will hopefully lead to new therapies.

Cystic appearance on magnetic resonance imaging in bihormonal growth hormone and prolactin tumors in acromegaly

PURPOSE

To investigate demographic, imaging and laboratory characteristics, and treatment outcomes of acromegaly patients who have bihormonal (BA) growth hormone (GH) and prolactin (PRL) immunoreactive adenomas compared to patients who have densely granulated GH adenomas (DGA) and sparsely granulated GH adenomas (SGA).

METHODS

Retrospective review of single-center surgically treated acromegaly patients; pathology was analyzed by a single neuropathologist using 2017 WHO criteria. Preoperative magnetic resonance imaging was assessed to evaluate tumor size, cystic component, invasion and T2 signal intensity.

RESULTS

Seventy-seven patients; 19 BA (9 mammosomatotroph and 10 mixed GH and PRL adenomas) were compared with 30 DGA, and 28 SGA. Patients with BA were older than SGA (49.6 vs 38.5 years, p = 0.035), had a higher IGF-1 index (3.3 vs 2.3, p = 0.040) and tumors were less frequently invasive (15.8% vs 57.1%, p = 0.005). BA more frequently had a cystic component on MRI than both SGA and DGA (52.6% vs 14.3%, and 22%, p = 0.005 and 0.033, respectively). When all histological types were combined, biochemical remission postoperatively was more common in non-cystic than cystic tumors (50% vs 22.5%, p = 0.042). Somatostatin receptor ligand response rate was 66.7%, 90.9% and 37.5% in BA, DGA and SGA patients, respectively (p = 0.053).

CONCLUSION

Imaging characteristics are an increasingly important adenoma behavior determinant. An adenoma cystic component may suggest that a GH adenoma is a BA. Cystic tumors exhibited lower rates of surgical remission in this series; therefore, optimized individual patient treatment is needed, as patients could be candidates for primary medical treatment.

Changing Hands: A Rising Role of the Tumor Surgeon in Teaching Sylvian Fissure Dissection

OBJECTIVE

The landscape of microneurosurgery has changed considerably over the past 2 decades, with a decline in indications for open surgery on cerebrovascular pathology and ever-increasing indications for open resection of brain tumors. This study investigated how these trends in case volume affected residents' training experiences in microsurgery and, specifically, Sylvian fissure dissection.

METHODS

Resident case logs were reviewed, identifying open cerebrovascular operations and craniotomies for tumor. Operations involving Sylvian fissure dissection were identified through operative reports. Changes in case number by resident were plotted over time, and linear regression was applied.

RESULTS

Among 23 chief residents, 3045 operations were identified, 1071 of which were for cerebrovascular pathology and 1974 for tumor. Open cerebrovascular experience decreased (P < 0.0001) while tumor volume remained unchanged (P = 0.221). The number of Sylvian fissure dissections per resident did not change over time overall (P = 0.583) or within cerebrovascular operations (P = 0.071). The number of Sylvian fissure dissections in tumor operations increased (P = 0.004). This effect was predominated by an increase in intraaxial tumors approached via Sylvian fissure dissection (P = 0.003). The proportion of Sylvian fissure dissections in tumor surgery increased from 15% in 2009 to 34% by 2019 (P = 0.003).

CONCLUSIONS

Residents are seeing an increasing proportion of their Sylvian fissure dissection experience during tumor operations. The distribution of this experience will continue to evolve as surgical indications change but suggests a growing role for tumor surgeons in resident training in microsurgery.

Pituitary society guidance: pituitary disease management and patient care recommendations during the COVID-19 pandemic-an international perspective

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the viral strain that has caused the coronavirus disease 2019 (COVID-19) pandemic, has presented healthcare systems around the world with an unprecedented challenge. In locations with significant rates of viral transmission, social distancing measures and enforced 'lockdowns' are the new 'norm' as governments try to prevent healthcare services from being overwhelmed. However, with these measures have come important challenges for the delivery of existing services for other diseases and conditions. The clinical care of patients with pituitary disorders typically involves a multidisciplinary team, working in concert to deliver timely, often complex, disease investigation and management, including pituitary surgery. COVID-19 has brought about major disruption to such services, limiting access to care and opportunities for testing (both laboratory and radiological), and dramatically reducing the ability to safely undertake transsphenoidal surgery. In the absence of clinical trials to guide management of patients with pituitary disease during the COVID-19 pandemic, herein the Professional Education Committee of the Pituitary Society proposes guidance for continued safe management and care of this population.

Distinguishing Extravascular from Intravascular Ferumoxytol Pools within the Brain: Proof of Concept in Patients with Treated Glioblastoma

BACKGROUND AND PURPOSE

Glioblastoma-associated macrophages are a major constituent of the immune response to therapy and are known to engulf the iron-based MR imaging contrast agent, ferumoxytol. Current ferumoxytol MR imaging techniques for localizing macrophages are confounded by contaminating intravascular signal. The aim of this study was to assess the utility of a newly developed MR imaging technique, segregation and extravascular localization of ferumoxytol imaging, for differentiating extravascular-from-intravascular ferumoxytol contrast signal at a delayed 24-hour imaging time point.

MATERIALS AND METHODS

Twenty-three patients with suspected post-chemoradiotherapy glioblastoma progression underwent ferumoxytol-enhanced SWI. Segregation and extravascular localization of ferumoxytol imaging maps were generated as the voxelwise difference of the delayed (24 hours) from the early (immediately after administration) time point SWI maps. Continuous segregation and extravascular localization of ferumoxytol imaging map values were separated into positive and negative components. Image-guided biologic correlation was performed.

RESULTS

Negative segregation and extravascular localization of ferumoxytol imaging values correlated with early and delayed time point SWI values, demonstrating that intravascular signal detected in the early time point persists into the delayed time point. Positive segregation and extravascular localization of ferumoxytol imaging values correlated only with delayed time point SWI values, suggesting successful detection of the newly developed extravascular signal.

CONCLUSIONS

Segregation and extravascular localization of ferumoxytol MR imaging improves on current techniques by eliminating intrinsic tissue and intravascular ferumoxytol signal and may inform glioblastoma outcomes by serving as a more specific metric of macrophage content compared with uncorrected T1 and SWI techniques.

MON-308 Pituitary Magnetic Resonance Imaging in the Postoperative Follow-Up of Patients with Acromegaly, Less Is More!

Background Patients (pts) with acromegaly (A) require long term follow up, as up to 15% will develop recurrence. Current guidelines for MRI surveillance recommend 12 week post-operative (postop) imaging for all pts and yearly if on pegvisomant (PEG). Many pts with residual tumor postop undergo repetitive imaging even when controlled with pituitary (PIT) directed therapies. However, gadolinium retention and healthcare costs are of increased concern. Aim Assess tumor growth postop and necessity of serial MRI in medically treated A pts. Methods Retrospective, IRB-approved, data analysis of pathology-proven A pts. Included were pts with at least 1 MRI at ≥1 year postop. Initial tumor size, invasion status, pathology, postop remission, MRIs, radiation and medical therapy data were collected. Biochemical (biochem) remission = normal IGF-1 and GH <1 at 3 mo postop. For pts with radiation, data was only collected up to radiation. Stats: t-test, chi-square. Results 83 pts were included; mean age 46±16 years, 45% female, mean follow up 7.9±5.3 years. 55 pts were on PIT-directed therapy (50 on somatostatin receptor ligands (SRL) alone, 1 on cabergoline (Cab) alone, 4 on SRL/Cab), 12 on PEG > 1 year (9 on PEG alone.) 11/83 (13.25%) had tumor growth at median 3.5 years (range 1-11). Tumors that grew were larger at diagnosis (25.21±10.93 mm vs 17.45±8.37 mm, p=0.004), had larger residuals postop (23.83±5.0 mm vs 11.86±7.47 mm, p=0.0003), and tended to be invasive (77.78% (7/9) vs 53.03% (35/66), p=NS). 7/11 were sparsely granulated and 4 mixed GH-PRL. Of 11 that grew, 8 had postop residual tumor, 3 in remission, 4 with discrepant IGF-1/GH, 2 uncontrolled and 2 with no data at 3 months postop. At the time of growth, 9/11 pts were untreated (6 had active A, 1 with discrepant IGF-1/GH and 2 with no IGF-1/GH data), 1 was controlled on pasireotide and one in biochem remission. Only 1/50 (2%) pts on pasireotide had growth and no pts on PEG >1 year. Discussion 86.75% of pts with A did not have tumor growth after surgery. Only one pt on PIT-targeted medications and none on PEG experienced tumor growth. Almost all pts who had growth had large invasive adenomas, majority were sparsely granulated, residual tumor postop, were biochemically uncontrolled and not on medication at the time of growth. A previous metanalysis of SRLs in A showed that tumor increase occurs in 1.4% (follow up 3-36 months). In our study pt follow up was longer and 1.82% (1/55) of pts who were on SRL/Cab had growth. Conclusion We recommend less frequent MRI monitoring for pts treated with PIT-targeted medications. Conversely, pts with residual adenoma not on medical therapy should be closely monitored biochemically and by serial MRIs. Further studies are needed to identify appropriate imaging interval for pts on medications and based on characteristics of aggression (such as sparsely granulated, large residual tumors, lack of biochemical control despite medications).

Combined iron oxide nanoparticle ferumoxytol and gadolinium contrast enhanced MRI define glioblastoma pseudoprogression

BACKGROUND

Noninvasively differentiating therapy-induced pseudoprogression from recurrent disease in patients with glioblastoma is prospectively difficult due to the current lack of a biologically specific imaging metric. Ferumoxytol iron oxide nanoparticle MRI contrast characterizes innate immunity mediated neuroinflammation; therefore, we hypothesized that combined ferumoxytol and gadolinium enhanced MRI could serve as a biomarker of glioblastoma pseudoprogression.

METHODS

In this institutional review board-approved, retrospective study, we analyzed ferumoxytol and gadolinium contrast enhanced T1-weighted 3T MRI in 45 patients with glioblastoma over multiple clinical timepoints. Isocitrate dehydrogenase 1 (IDH-1) mutational status was characterized by exome sequencing. Sum of products diameter measurements were calculated according to Response Assessment in Neuro-Oncology criteria from both gadolinium and ferumoxytol enhanced sequences. Enhancement mismatch was calculated as the natural log of the ferumoxytol to gadolinium sum of products diameter ratio. Analysis of variance and Student's t-test assessed differences in mismatch ratios. P-value <0.05 indicated statistical significance.

RESULTS

With the development of pseudoprogression we observed a significantly elevated mismatch ratio compared with disease recurrence (P < 0.01) within IDH-1 wild type patients. Patients with IDH-1 mutation demonstrated significantly reduced mismatch ratio with the development of pseudoprogression compared with disease recurrence (P < 0.01). Receiver operator curve analysis demonstrated 100% sensitivity and specificity for the use of mismatch ratios as a diagnostic biomarker of pseudoprogression.

CONCLUSION

Our study suggests that ferumoxytol to gadolinium contrast mismatch ratios are an MRI biomarker for the diagnosis of pseudoprogression in patients with glioblastoma. This may be due to the unique characterization of therapy-induced neuroinflammation.

Subarachnoid Hemorrhage Pattern Predicts Acute Cerebral Blood Flow Response in the Rat

There is considerable variability in the presentation of patients with acute subarachnoid hemorrhage (aSAH). Evidence suggests that a thick, diffuse clot better predicts the development of delayed cerebral ischemia and poor outcomes. In a rodent model of acute SAH, we directly measured the effects of the volume of blood injected versus the pattern of distribution of hemorrhage in the subarachnoid space on markers of early brain injury, namely, cerebral blood flow (CBF), cerebrospinal fluid (CSF) concentrations of P450 eicosanoids and catecholamines, and cortical spreading depolarizations (CSDs). There is a significant decrease in CBF, an increase in CSF biomarkers, and a trend toward increasing frequency and severity of CSDs when grouped by severity of hemorrhage but not by volume of blood injected. In severe hemorrhage grade animals, there was a progressive decrease in CBF after successive CSD events. These results suggest that the pattern of SAH (thick diffuse clots) correlates with the "clinical" severity of SAH.

Hypercoagulability in Cushing Syndrome, Prevalence of Thrombotic Events: A Large, Single-Center, Retrospective Study

Background

The risk of Cushing syndrome (CS) patients experiencing a thrombotic event (TE) is significantly higher (odds ratio; OR 18%) than that of the general population. However, there are currently no anticoagulation guidelines.

Methods

A retrospective, single-center, longitudinal study of patients undergoing all types of treatment—surgical (pituitary, unilateral, and bilateral adrenalectomy) and medical treatment—was undertaken. TEs were recorded at any point up until last patient follow-up; myocardial infarction (MI), deep venous thrombosis (DVT), and pulmonary embolism (PE) or stroke. Patients’ doses and complications of anticoagulation were recorded.

Results

Included were 208 patients; a total of 165 (79.3%) were women, and mean age at presentation was 44 ± 14.7 years. Thirty-nine (18.2%) patients had a TE; extremity DVT (38%), cerebrovascular accident (27%), MI (21%), and PE (14%). Of 56 TEs, 27 (48%) were arterial and 29 (52%) were venous. Patients who underwent bilateral adrenalectomy (BLA) had an odds ratio of 3.74 (95% CI 1.69-8.27) of developing a TE. Of patients with TEs, 40.5% experienced the event within the first 60 days after surgery. Baseline 24-hour urinary free cortisol levels did not differ in patients with or without TE after BLA. Of 197 patients who underwent surgery, 50 (25.38%) received anticoagulation after surgery, with 2% having bleeding complications.

Conclusions

The risk of TEs in patients with CS was approximately 20%. Many patients had more than 1 event, with higher risk 30 to 60 days postoperatively. The optimal prophylactic anticoagulation duration is unknown, but most likely needs to continue up to 60 days postoperatively, particularly after BLA.

External retrospective validation of Brain Injury Guidelines criteria and modified guidelines for improved care value in the management of patients with low-risk neurotrauma

OBJECTIVE

Conventional management of patients with neurotrauma frequently consists of routine, repeat head CT at preordained intervals with ICU-level monitoring, regardless of injury severity. The Brain Injury Guidelines (BIG) are a classification tool for stratifying patients into injury severity and risk-of-progression categories based on presenting clinical and radiographic findings. In the present study, the authors aimed to validate BIG criteria at a single level 1 trauma center.

METHODS

Patients were classified according to BIG criteria and evaluated for subsequent radiographic progression or development of neurological decline. A 2-year retrospective cohort review of consecutive patients with neurotrauma (n = 590) was undertaken. The authors then developed a modified BIG algorithm for use at their institution and followed its implementation prospectively over 555 consecutive patients.

RESULTS

In the retrospective analysis, no patient in the BIG 1 category (n = 88, 14.9%) demonstrated progression or neurological decline, and 7.5% of BIG 2 patients (n = 107, 18.1%) demonstrated mild radiographic progression without any decline or need for additional neurosurgical or medical intervention, whereas 15.4% of BIG 3 patients (n = 395, 66.9%) underwent additional neurosurgical procedures. In the prospective analysis, no BIG 1 (n = 105, 18.9%) or BIG 2 (n = 48, 8.6%) patients demonstrated a clinical decline or required any further neurosurgical intervention. By contrast, 12.9% of BIG 3 patients (n = 402, 72%) required immediate neurosurgical intervention, and a further 2.0% required delayed intervention based on clinical and/or radiographic evidence of injury progression.

CONCLUSIONS

Application of the BIG criteria in a single large level 1 trauma center reliably sorted patients into appropriate risk categories that accurately guided ongoing management.

Arteriovenous Malformation Presenting as Symptomatic, Enlarging and Contrast-Enhancing Mass 12 Years After Being Treated with Embolization and Radiotherapy

BACKGROUND

Gross total resection of arteriovenous malformations (AVMs) of the central nervous system confirmed by formal angiography is accepted as a cure for patients. In some cases, this may not be possible. Even though in these cases other treatment modalities such as endovascular embolization and radiotherapy can be used, long-term follow-up is lacking in the literature.

CASE DESCRIPTION

Here we report a case of a 57-year-old woman with history of a right-sided parieto-occipital/periatrial AVM, initially treated with a combination of endovascular embolization and radiotherapy.

CONCLUSIONS

The patient subsequently presented (12 years later) with a symptomatic, enlarging, contrast-enhancing mass at the same location that was angiographically occult but ultimately proven to be an AVM on a background of reactive changes on pathology.

High prevalence of adrenal insufficiency at diagnosis and headache recovery in surgically resected Rathke's cleft cysts-a large retrospective single center study

BACKGROUND

Rathke's cleft cysts (RCC) are lesions that arise from Rathke's pouch. Though frequently incidental, resulting symptoms in a minority of cases are indicators for surgical resection, which may prove beneficial.

OBJECTIVE

To characterize a cohort of surgically-resected RCC cases at Oregon Health & Science University; tabulate associated hormonal imbalances and symptoms, possible symptom reversal with surgery, determine recurrence risk; identify predictors of recurrence and headache improvement.

METHOD

Electronic records of all RCC resected cases (from 2006-2016; 11 years) were retrospectively reviewed. Patients had been evaluated by one neuroendocrinologist using a uniform protocol.

RESULTS

A pathological RCC diagnosis was established in 73 of 814 (9%) surgical pituitary cases. The RCC cohort was 77% (n = 56/73) female, mean age was 39.5 ± 14.9 years at first surgery, and at presentation headache was reported in 88% and visual defects/diplopia in 18% of patients. Initial RCC maximum diameter was 1.3 ± 0.7 cm. The most frequent hormonal deficit was cortisol; 24% of patients had a new adrenal insufficiency (AI) diagnosis, however, 36% also had AI at 3 months post-operatively. Mean follow up was 4.0 ± 4.5 years. Two-thirds of patients (41/62) had headache improvement 3 months post-operatively. Post-operative imaging revealed no residual cyst in 58% (38/65). In those patients with no residual RCC, 29% had recurrence and 71% had long lasting cure. From the 42% (27/65) of patients with residual cyst on post-operative imaging; 59% (16/27) remained stable, 26% (7/27) progressed and 15% (4/27) regressed.

CONCLUSION

Symptomatic RCC present mostly in women, with a high proportion reporting headaches. Prevalence of AI at diagnosis is high. Surgery may not achieve adrenal axis recovery, but renders a high percentage of headache improvement. Approximately 25% of RCC will recur by 4 years postoperatively. Clinicians should cautiously screen patients with symptomatic RCC, regardless of lesion size for AI.

Surgical Parameters for Minimally Invasive Trans-Eustachian Tube CSF Leak Repair: A Cadaveric Study and Literature Review

BACKGROUND

Cerebrospinal fluid rhinorrhea from a lateral skull base defect refractory to spontaneous healing and/or conservative management is most commonly managed via open surgery. Approach for repair is dictated by location of the defect, which may require surgical exploration. The final common pathway is the eustachian tube (ET). Endoscopic ET obliteration via endonasal and lateral approaches is under development. Whereas ET anatomy has been studied, surgical landmarks have not been previously described or quantified. We aimed to define surgical parameters of specific utility to endoscopic ET obliteration.

METHODS

A literature review was performed of known ET anatomic parameters. Next, using a combination of endoscopic and open techniques in cadavers, we cannulated the intact ET and dissected its posterior component to define the major curvature position of the ET, defined as the genu, and quantified the relative distances through the ET lumen. The genu was targeted as a major obstacle encountered when cannulating the ET from the nasopharynx.

RESULTS

Among 10 ETs, we found an average distance of 23 ± 5 mm from the nasopharynx to the ET genu, distance of 24 ± 3 mm from the genu to the anterior aspect of the tympanic membrane and total ET length of 47 ± 4 mm.

CONCLUSIONS

Although membranous and petrous components of the ET are important to its function, the genu may be a more useful surgical landmark. Basic surgical parameters for endoscopic ET obliteration are defined.

Clinical outcomes in male patients with lactotroph adenomas who required pituitary surgery: a retrospective single center study

PURPOSE

Lactotroph adenomas (LA) are the most frequently encountered pituitary tumors. Although more frequently observed in women, LAs in men were recently included in a more aggressive category regardless of histological grading, by the WHO. We aimed to perform a rigorous retrospective review of a single center's pre-operative evaluation, patient characteristics and outcomes of male LAs patients requiring pituitary surgery.

METHODS

A retrospective review, over 11 years, of patients who underwent resection of a pituitary adenoma at a single center was conducted. Predictors of persistent disease in male LAs patients along with a comparison to predictors of silent corticotroph adenomas (SCAs) patients who also underwent surgery at the center was also conducted.

RESULTS

Thirty-one male patients with LAs were identified. When compared to SCAs patients, LAs male patients were younger (41 vs. 50 years of age, p = 0.01). Men with LAs had more invasive tumors (75% vs. 44.7% p = 0.02). More LAs in men had residual tumor after surgery than patients with SCA (92.6% vs. 42.1%, p < 0.001). Male patients with LAs and patients with SCA had similar rates of requiring additional surgery (28.9% vs. 24.1%, p = NS) and radiation therapy (18.4% vs. 19.4%, p = NS).

CONCLUSIONS

High rates of DA resistance, invasive tumors and postoperative residual disease in male patients with LA who required surgery are shown. Surgery improved optic chiasm compression, PRL level and central hypogonadism but, not surprisingly, failed to normalize other pituitary hormones and/or eliminate need for DA therapy.

Silent somatotroph pituitary adenomas: an update

Silent growth hormone adenomas (SGHA) are a rare entity of non-functioning pituitary neuroendocrine tumors. Diagnosis is invariably made post-operatively of a tumor immunopositive for GH (and Pit-1 in selected cases) but without clinical acromegaly. Mainly young females are affected, and tumors are often uncovered by investigation for headaches or oligoamenorrhea. Integration of clinical, pathological and biochemical data is required for proper diagnosis. Beside normal IGF-1 levels, a third of SGHAs displays elevated GH levels and some will eventually progress to acromegaly. Almost two-thirds will be mixed GH-prolactin tumors and sparsely-granulated monohormonal GH tumors seems the more aggressive subtype. Recurrence and need for radiation is higher than other non-functioning tumors so close follow-up is warranted.

Minimally invasive endoscopic repair of refractory lateral skull base cerebrospinal fluid rhinorrhea: case report and review of the literature

Cerebrospinal fluid (CSF) leaks occur in approximately 10% of patients undergoing a translabyrinthine, retrosigmoid, or middle fossa approach for vestibular schwannoma resection. Cerebrospinal fluid rhinorrhea also results from trauma, neoplasms, and congenital defects. A high degree of difficulty in repair sometimes requires repetitive microsurgical revisions-a rate of 10% of cases is often cited. This can not only lead to morbidity but is also costly and burdensome to the health care system. In this case-based theoretical analysis, the authors summarize the literature regarding endoscopic endonasal techniques to obliterate the eustachian tube (ET) as well as compare endoscopic endonasal versus open approaches for repair. Given the results of their analysis, they recommend endoscopic endonasal ET obliteration (EEETO) as a first- or second-line technique for the repair of CSF rhinorrhea from a lateral skull base source refractory to spontaneous healing and CSF diversion. They present a case in which EEETO resolved refractory CSF rhinorrhea over a 10-month follow-up after CSF diversions, wound reexploration, revised packing of the ET via a lateral microscopic translabyrinthine approach, and the use of a vascularized flap had failed. They further summarize the literature regarding studies that describe various iterations of EEETO. By its minimally invasive nature, EEETO imposes less morbidity as well as less risk to the patient. It can be readily implemented into algorithms once CSF diversion (for example, lumbar drain) has failed, prior to considering open surgery for repair. Additional studies are warranted to further demonstrate the outcome and cost-saving benefits of EEETO as the data until now have been largely empirical yet very hopeful. The summaries and technical notes described in this paper may serve as a resource for those skull base teams faced with similar challenging and otherwise refractory CSF leaks from a lateral skull base source.

Clinical profile of silent growth hormone pituitary adenomas; higher recurrence rate compared to silent gonadotroph pituitary tumors, a large single center experience

PURPOSE

Study and comparison of characteristics of silent growth hormone adenomas (SGHA), silent corticotroph adenomas (SCA), and silent gonadotroph adenomas (SGA) in a single institution cohort of surgically treated pituitary adenomas.

METHODS

Retrospective analysis of SGHA surgically resected over 10 years: SGHA was defined as no clinical or biochemical evidence of acromegaly and positive GH immunostaining.

RESULTS

Of 814 pituitary surgeries; 2.1% (n = 17) were SGHA, 4.5% (n = 37) SCA, and 18.9% (n = 70/371; 2011-2016) SGA. Mean age at SGHA diagnosis was 43 years, with a large female predominance (82%). Mean tumor size and cavernous/sphenoid sinus invasiveness for SGHA, SCA, and SGA were 1.5 ± 1.0 cm and 25%, 2.5 ± 1.2 cm and 43%, 2.9 ± 2.0 cm and 41%, respectively (tumor size p = 0.009, SGHA vs. SGA, and invasion p; not-significant). During mean follow-up of 3.9 years, two patients (11%) developed elevated insulin-like growth factor-1 and five patients (29%) required a second surgery for tumor recurrence. Rate of surgical reintervention was similar to SCA (31%), but higher than SGA (10%) (p = 0.035, SGHA vs. SGA), and 18% underwent radiation therapy, similar to SCA (19%, p; not-significant) but higher than SGA (2.9%, p = 0.018).

CONCLUSION

This is the largest single center study characterizing SGHA behavior with SGA and SCA control groups in a cohort of surgically resected pituitary adenomas. SGHA present mostly in young females, and should be closely followed due to their higher likelihood of recurrence and potential of progression to clinical acromegaly. We propose that a complete hormonal staining panel be routinely performed for all pituitary adenomas.

Candida Meningitis After Transsphenoidal Surgery: A Single-Institution Case Series and Literature Review

Candida meningitis after neurosurgical procedures is a rare but potentially devastating complication. The presentation of meningitis can be insidious in immunosuppressed patients and thus can be easily overlooked. Cerebrospinal fluid studies often resemble bacterial profiles, and cultures can be falsely negative. Candida albicans is the most common species identified in postsurgical Candida meningitis, and delay in diagnosis and treatment can be devastating. The standard induction therapy for Candida meningitis has been amphotericin B combined with flucytosine. A high index of suspicion is needed in any patient with risk factors such as abdominal surgery, bowel perforation, recent broad spectrum antibiotic therapy, intravenous drug use, extremes of age, indwelling catheters, and immunosuppression such as AIDS, malignancy, antineoplastic therapy, and steroid use. Here, we describe 3 case presentations of patients with giant skull base tumors who developed postsurgical Candida meningitis, each with vastly different clinical courses and outcomes, ranging from benign to catastrophic. We performed a literature review with special focus on common risk factors, Candida species, diagnostic criteria, and treatment.

Quantitative Anterior and Posterior Clinoidectomy Analysis and Mobilization of the Oculomotor Nerve during Surgical Exposure of the Basilar Apex Using Frameless Stereotaxis

Background  Anterior and posterior clinoidectomies have been proposed to augment exposure of the basilar apex. A sequential quantitative benefit analysis offered by these maneuvers has not been reported. Methods  Fourteen datasets from eight cadaveric specimens were analyzed. A modified orbitozygomatic frontotemporal craniotomy was performed. The extent of proximal control of the basilar artery was determined through the exposed opticocarotid and carotidoculomotor triangles before and after clinoidectomies and mobilization of the third nerve at the porous oculomotarius. Results  Removal of the anterior and posterior clinoids significantly improved proximal basilar artery access ( p  < 0.012) and increased the opticocarotid triangle and carotidoculomotor triangle areas ( p  < 0.017). Surgical freedom increased inferosuperiorally in the opticocarotid triangle following anterior clinoidectomy ( p  < 0.047) and in carotidoculomotor triangle following posterior clinoidectomy ( p  < 0.047). Mobilization of the third nerve increased surgical freedom in the mediolateral projection of the carotidoculomotor triangle ( p  < 0.047). Conclusion  Anterior and posterior clinoidectomies significantly improved the area of exposure of the opticocarotid triangle, carotidoculomotor triangle, and the exposed length of the basilar artery available for proximal control. This improvement is extremely important for large or giant aneurysms of the upper basilar artery or aneurysms hidden by the posterior clinoid.

Current and potential imaging applications of ferumoxytol for magnetic resonance imaging

Contrast-enhanced magnetic resonance imaging is a commonly used diagnostic tool. Compared with standard gadolinium-based contrast agents, ferumoxytol (Feraheme, AMAG Pharmaceuticals, Waltham, MA), used as an alternative contrast medium, is feasible in patients with impaired renal function. Other attractive imaging features of i.v. ferumoxytol include a prolonged blood pool phase and delayed intracellular uptake. With its unique pharmacologic, metabolic, and imaging properties, ferumoxytol may play a crucial role in future magnetic resonance imaging of the central nervous system, various organs outside the central nervous system, and the cardiovascular system. Preclinical and clinical studies have demonstrated the overall safety and effectiveness of this novel contrast agent, with rarely occurring anaphylactoid reactions. The purpose of this review is to describe the general and organ-specific properties of ferumoxytol, as well as the advantages and potential pitfalls associated with its use in magnetic resonance imaging. To more fully demonstrate the applications of ferumoxytol throughout the body, an imaging atlas was created and is available online as supplementary material.

Dual Endoscopic Endonasal Transsphenoidal and Precaruncular Transorbital Approaches for Clipping of the Cavernous Carotid Artery: A Cadaveric Simulation

Background Endoscopic skull base approaches are being used to address complicated neurovascular pathology. These approaches are safest when proximal vascular control of the cavernous carotid artery (CavCA) can be obtained. Methods We present a cadaver-based anatomic simulation study showing the feasibility of clip placement for the CavCA as it courses through the cavernous sinus. The arterial vessels were injected with red microfil (Flow Tech, Carver, Massachusetts) to enhance visibility. The endoscope was directed through a precaruncular transorbital approach and instrumentation was managed through an endonasal transsphenoidal approach. Results The dual approach minimized the "coning down" and instrument "sword fighting" that occurs as the rod lens endoscope and instruments are used laterally and posterior toward the clivus and brainstem. The precaruncular transorbital approach improved visualization of the clip application and improved the functional working area. The transorbital port allowed better appreciation of the distal clip tines, and the laterally positioned cranial nerves. Conclusions The advantages may be most realized in the setting of endoscopic endonasal resection of highly vascular lesions and/or bleeding from a ruptured aneurysm being clipped. Simulated training provides an excellent opportunity to enhance skill sets and increase familiarity with anatomical visualization before entering the operative arena.

Hibernation, Hypothermia and a Possible Therapeutic "Shifted Homeostasis" Induced by Central Activation of A1 Adenosine Receptor (A1AR)

The positive outcome that hypothermia contributes to brain and cardiac protection following ischemia has stimulated research in the development of pharmacological approaches to induce a hypothermic/hypometabolic state. Pharmacological manipulation of central autonomic thermoregulatory circuits could represent a potential target for the induction of a hypothermic state. Here we present a brief description of the CNS thermoregulatory centers and how the manipulation of these circuits can be useful in the treatment of pathological conditions such as stroke or brain hemorrhage.

Protective role of p450 epoxyeicosanoids in subarachnoid hemorrhage

BACKGROUND

Patients recovering from aneurysmal subarachnoid hemorrhage (SAH) are at risk for developing delayed cerebral ischemia (DCI). Experimental and human studies implicate the vasoconstrictor P450 eicosanoid 20-hydroxyeicosatetraenoic acid (20-HETE) in the pathogenesis of DCI. To date, no studies have evaluated the role of vasodilator epoxyeicosatrienoic acids (EETs) in DCI.

METHODS

Using mass spectrometry, we measured P450 eicosanoids in cerebrospinal fluid (CSF) from 34 SAH patients from 1 to 14 days after admission. CSF eicosanoid levels were compared in patients who experienced DCI versus those who did not. We then studied the effect of EETs in a model of SAH using mice lacking the enzyme soluble epoxide hydrolase (sEH), which catabolizes EETs into their inactive diol. To assess changes in vessel morphology and cortical perfusion in the mouse brain, we used optical microangiography, a non-invasive coherence-based imaging technique.

RESULTS

Along with increases in 20-HETE, we found that CSF levels of 14,15-EET were elevated in SAH patients compared to control CSF, and levels were significantly higher in patients who experienced DCI compared to those who did not. Mice lacking sEH had elevated 14,15-EET and were protected from the delayed decrease in microvascular cortical perfusion after SAH, compared to wild type mice.

CONCLUSIONS

Our findings suggest that P450 eicosanoids play an important role in the pathogenesis of DCI. While 20-HETE may contribute to the development of DCI, 14,15-EET may afford protection against DCI. Strategies to enhance 14,15-EET, including sEH inhibition, should be considered as part of a comprehensive approach to prevent DCI.

Soluble Epoxide Hydrolase in Hydrocephalus, Cerebral Edema, and Vascular Inflammation After Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Acute communicating hydrocephalus and cerebral edema are common and serious complications of subarachnoid hemorrhage (SAH), whose causes are poorly understood. Using a mouse model of SAH, we determined whether soluble epoxide hydrolase (sEH) gene deletion protects against SAH-induced hydrocephalus and edema by increasing levels of vasoprotective eicosanoids and suppressing vascular inflammation.

METHODS

SAH was induced via endovascular puncture in wild-type and sEH knockout mice. Hydrocephalus and tissue edema were assessed by T2-weighted magnetic resonance imaging. Endothelial activation was assessed in vivo using T2*-weighted magnetic resonance imaging after intravenous administration of iron oxide particles linked to anti-vascular cell adhesion molecule-1 antibody 24 hours after SAH. Behavioral outcome was assessed at 96 hours after SAH with the open field and accelerated rotarod tests.

RESULTS

SAH induced an acute sustained communicating hydrocephalus within 6 hours of endovascular puncture in both wild-type and sEH knockout mice. This was followed by tissue edema, which peaked at 24 hours after SAH and was limited to white matter fiber tracts. sEH knockout mice had reduced edema, less vascular cell adhesion molecule-1 uptake, and improved outcome compared with wild-type mice.

CONCLUSIONS

Genetic deletion of sEH reduces vascular inflammation and edema and improves outcome after SAH. sEH inhibition may serve as a novel therapy for SAH.

Genetic variation in soluble epoxide hydrolase: association with outcome after aneurysmal subarachnoid hemorrhage

OBJECT

Patients with aneurysmal subarachnoid hemorrhage (SAH) are at high risk for delayed cerebral ischemia (DCI) and stroke. Epoxyeicosatrienoic acids (EETs) play an important role in cerebral blood flow regulation and neuroprotection after brain injury. Polymorphisms in the gene for the enzyme soluble epoxide hydrolase (sEH), which inactivates EETs, are associated with ischemic stroke risk and neuronal survival after ischemia. This prospective observational study of patients with SAH compares vital and neurologic outcomes based on functional polymorphisms of sEH.

METHODS

Allelic discrimination based on quantitative real-time polymerase chain reaction was used to differentiate wild-type sEH from K55R heterozygotes (predictive of increased sEH activity and reduced EETs) and R287Q heterozygotes (predictive of decreased sEH activity and increased EETs). The primary outcome was new stroke after SAH. Secondary outcomes were death, Glasgow Outcome Scale score, and neurological deterioration attributable to DCI.

RESULTS

Multivariable logistic regression models adjusted for age at admission and Glasgow Coma Scale scores revealed an increase in the odds of new stroke (OR 5.48 [95% CI 1.51-19.91]) and death (OR 7.52 [95% CI 1.27-44.46]) in the K55R group, but no change in the odds of new stroke (OR 0.56 [95% CI 0.16-1.96]) or death (OR 3.09 [95% CI 0.51-18.52]) in patients with R287Q genotype, compared with wild-type sEH. The R287Q genotype was associated with reduced odds of having a Glasgow Outcome Scale score of ≤ 3 (OR 0.23 [95% CI 0.06-0.82]). There were no significant differences in the odds of neurological deterioration due to DCI.

CONCLUSIONS

Genetic polymorphisms of sEH are associated with neurological and vital outcomes after aneurysmal SAH.

Intracisternal administration of tissue plasminogen activator improves cerebrospinal fluid flow and cortical perfusion after subarachnoid hemorrhage in mice

Early brain injury (EBI) during the first 72 h after subarachnoid hemorrhage (SAH) is an important determinant of clinical outcome. A hallmark of EBI, global cerebral ischemia, occurs within seconds of SAH and is thought to be related to increased intracranial pressure (ICP). We tested the hypothesis that ICP elevation and cortical hypoperfusion are the result of physical blockade of cerebrospinal fluid (CSF) flow pathways by cisternal microthrombi. In mice subjected to SAH, we measured cortical blood volume (CBV) using optical imaging, ICP using pressure transducers, and patency of CSF flow pathways using intracisternally injected tracer dye. We then assessed the effects of intracisternal injection of recombinant tissue plasminogen activator (tPA). ICP rose immediately after SAH and remained elevated for 24 h. This was accompanied by a decrease in CBV and impaired dye movement. Intracisternal administration of tPA immediately after SAH lowered ICP, increased CBV, and partially restored CSF flow at 24 h after SAH. Lowering ICP without tPA, by draining CSF, improved CBV at 1 h, but not 24 h after SAH. These findings suggest that blockade of CSF flow by microthrombi contributes to the early decline in cortical perfusion in an ICP-dependent and ICP-independent manner and that intracisternal tPA may reduce EBI and improve outcome after SAH.

Delayed intracranial hypertension after cranial vault remodeling for nonsyndromic single-suture synostosis

OBJECT

Delayed intracranial hypertension may occur after cranial vault remodeling for synostosis and may result in visual loss and developmental delay. Delayed intracranial hypertension is relatively common in children with syndromic, multisuture synostosis, but the incidence is poorly defined in children with single-suture nonsyndromic synostosis. This study evaluates the frequency of reoperation for delayed intracranial hypertension after single-suture synostosis repair.

METHODS

Patients who had undergone cranial vault remodeling for nonsyndromic single-suture synostosis and were treated at a single tertiary pediatric hospital between July 2000 and December 2010 were analyzed for the occurrence of delayed intracranial hypertension and reoperation for cranial vault remodeling.

RESULTS

Eighty-one patients with clinical follow-up of at least 3 years were analyzed from a total of 156 consecutive patients. The average patient age at the initial operation was 9.1 months. Five (6.2%) of 81 patients presented with delayed clinical and ophthalmological signs and symptoms of intracranial hypertension following initial cranial vault reconstruction, confirmed indirectly in each case by CT findings and directly by intracranial pressure monitoring. These 5 patients underwent repeat cranial vault reconstruction.

CONCLUSIONS

Calvarial growth restriction and intracranial hypertension occur sporadically following primary cranial vault reconstruction for single-suture nonsyndromic cranial synostosis. In this series, delayed intracranial hypertension occurred only in male patients who underwent primary repair of isolated sagittal synostoses at an age less than or equal to 5 months.

The deleterious effects of methamphetamine use on initial presentation and clinical outcomes in aneurysmal subarachnoid hemorrhage

Object

The objective of this study was to retrospectively look at methamphetamine (MA) use in patients with aneurysmal subarachnoid hemorrhage (SAH) to determine if MA use affects clinical presentation and outcomes after aneurysmal SAH.

Methods

A retrospective review of patients admitted to the Oregon Health & Science University neurosurgical service with aneurysmal SAH during the past 6 years was undertaken. Variables analyzed included MA use, age, sex, cigarette use, Hunt and Hess grade, Fisher grade, admission blood pressure, aneurysm characteristics, occurrence of vasospasm, hospital length of stay (LOS), cerebral infarction, aneurysm treatment, and Glasgow Outcome Scale (GOS) score. Data differences between MA users and nonusers were statistically analyzed using multivariate logistic regression analysis. A separate comparison with randomly selected age-matched nonuser controls was also performed.

Results

Twenty-eight (7%) of 374 patients with aneurysmal SAH were identified as MA users. Methamphetamine users were younger than nonusers (45.2 vs 55.9 years, respectively; p <0.001). Despite a younger age, MA users had significantly higher Hunt and Hess grades than nonusers (3.0 vs 2.5, respectively; p <0.020) and age-matched controls (3.0 vs 2.0, respectively; p <0.001). Earliest available mean arterial pressure was significantly higher in MA users (122.1 vs 109.7, respectively; p = 0.005) than all nonusers but not age-matched controls. Methamphetamine users had significantly higher vasospasm rates than nonusers (92.9% vs 71.1%, respectively; p = 0.008) but similar rates as age-matched controls (92.9% vs 89.3%, respectively; p = 0.500). Glasgow Outcome Scale score did not differ significantly between users and nonusers (3 vs 4, respectively; p = 0.170), but users had significantly lower GOS scores than age-matched controls (3 vs 5, respectively; p <0.001). There was no statistically significant difference in the LOS between users and nonusers (18 days vs 16 days, respectively; p = 0.431) or users and age-matched controls (18 days vs 14 days, respectively; p = 0.250). In the multivariate analysis, MA use (OR 3.777, p = 0.018), age (p <0.001), Fisher grade (p = 0.011), Hunt and Hess grade (p <0.001), and cerebral infarction (p <0.001) were predictors of poor GOS score. The only predictor of vasospasm was age (p <0.001), although a strong predictive trend in MA use (p = 0.149) was found. Predictors of a hospital LOS >15 days included age (p = 0.002), Fisher grade (p = 0.002), Hunt and Hess grade (p <0.001), and cerebral infarction (p <0.001). Predictors of cerebral infarction include male sex (p = 0.022) and Hunt and Hess grade (p = 0.006), with vasospasm demonstrating a strong trend (p = 0.056).

Conclusions

A history of MA use may predict poorer outcomes in patients who present with aneurysmal SAH. Methamphetamine users have significantly worse presentations and outcomes when compared with age-matched controls.

Steroid psychosis: a review for neurosurgeons

Steroids are beneficial in neurological illness, but have many serious side effects. Having observed several patients with severe steroid psychoses, which greatly prolonged their hospitalizations, the authors sought to improve understanding of this entity. A literature review was conducted. The incidence of severe psychiatric symptoms was estimated in a meta-analysis of 2,555 patients to be 5.7 % and the incidence of any psychiatric symptoms was 18.6 % in patients receiving >80 mg/day of prednisone (12 mg/day dexamethasone). Dose is not predictive of time of onset, severity, type, or duration of symptoms. Symptoms can develop rapidly following exposure to even low doses and with oral, epidural, or intra-articular administration. Glucocorticoid effects on the brain fall into three categories: genomic, non-genomic, and neurotrophic/neurotoxic and can be permanent. Excessive glucocorticoid exposure may result in decreased production of endogenous neurosteroid molecules, resulting in unopposed glucocorticoid effects. Treatment includes early recognition, steroid withdrawal when appropriate, reduction in stimulation, and medication. Atypical antipsychotics like olanzapine and risperidone may cause fewer dystonic reactions and extrapyramidal symptoms than typical antipsychotics like haloperidol, and therefore, are often recommended as first line treatment. Steroids are powerful medications with many undesirable side effects. They should be used with caution. More research is needed on their effects on the human central nervous system.

Abstract 109: Soluble Epoxide Hydrolase Gene Deletion is Protective Against Delayed Microvascular Vasospasm in a Mouse Model of Subarachnoid Hemorrhage

Accumulating evidence supports a role for microvascular dysfunction in the development of delayed cerebral ischemia following subarachnoid hemorrhage (SAH). The mechanism underlying delayed microvascular vasospasm (dMVS) is unknown. Using 3-dimensional, quantitative optical microangiography (OMAG), we assessed early and delayed changes in perfusion and dimensions of cerebrocortical microvessels in a mouse model of SAH. We tested the hypothesis that the development of dMVS after SAH is linked to changes in expression of soluble epoxide hydrolase (sEH), a key enzyme in the metabolism of a group of vasodilator eicosanoids called epoxyeicosatrienoic acids (EETs). Wild-type (WT, n=6) mice and mice lacking the sEH gene (sEHKO, n=4) were subjected to endovascular perforation to induce SAH, and followed for 72 hours to assess dMVS using OMAG. At 24 hours after SAH, no apparent change in cortical perfusion was observed in either WT or sEHKO mice compared to baseline (p>0.05), although both strains experienced constriction of individual cortical microvessels (-7.4 +/- 1.1% and -6.2 +/- 1.2% change from baseline (p<0.05) in WT and sEHKO mice respectively). At 72 hours after SAH, WT mice developed further microvascular vasoconstriction (-9.6 +/- 1% change from baseline (p<0.05 compared to baseline and 24h) ) and sustained a significant decrease (14.5 +/- 4.5% ) in cortical perfusion compared to baseline perfusion (p<0.05), whereas sEHKO mice did not show further changes in microvascular diameters, and were protected from the delayed drop in cortical perfusion. We conclude that genetic deletion of sEH can protect against dMVS in a mouse model of SAH. Our results suggest that EETs pathway may be involved in the pathogenesis of dMVS following SAH.

Preoperative identification of the facial nerve in patients with large cerebellopontine angle tumors using high-density diffusion tensor imaging

OBJECT

Facial nerve paresis can be a devastating complication following resection of large (> 2.5 cm) cerebellopontine angle (CPA) tumors. The authors have developed and used a new high-density diffusion tensor imaging (HD-DT imaging) method, aimed at preoperatively identifying the location and course of the facial nerve in relation to large CPA tumors. Their study objective was to preoperatively identify the facial nerve in patients with large CPA tumors and compare their HD-DT imaging method with a traditional standard DT imaging method and correlate with intraoperative findings.

METHODS

The authors prospectively studied 5 patients with large (> 2.5 cm) CPA tumors. All patients underwent preoperative traditional standard- and HD-DT imaging. Imaging results were correlated with intraoperative findings.

RESULTS

Utilizing their HD-DT imaging method, the authors positively identified the location and course of the facial nerve in all patients. In contrast, using a standard DT imaging method, the authors were unable to identify the facial nerve in 4 of the 5 patients.

CONCLUSIONS

The HD-DT imaging method that the authors describe and use has proven to be a powerful, accurate, and rapid method for preoperatively identifying the facial nerve in relation to large CPA tumors. Routine integration of HD-DT imaging in preoperative planning for CPA tumor resection could lead to improved facial nerve preservation.

Levodopa-responsive parkinsonism after aneurysmal subarachnoid hemorrhage

BACKGROUND

Levodopa-responsive Parkinsonism is a rare complication of subarachnoid hemorrhage and no cases have been reported to occur in the absence of hydrocephalus.

METHODS

Case report.

RESULTS

We describe a 42-year-old woman who developed progressive severe Parkinsonism in the second week after aneurysmal subarachnoid hemorrhage. No hydrocephalus was present. Neuroimaging revealed striking abnormalities of the midbrain in the region of the substantia nigra. She was ultimately treated with high dose levodopa/carbidopa with a dramatic response.

CONCLUSIONS

This case suggests that Parkinsonism may occur as a delayed complication of subarachnoid hemorrhage, and that in these patients, a trial of levodopa-carbidopa may be warranted.

Destructive procedures for control of cancer pain: the case for cordotomy

Object

Historically, destructive procedures for cancer pain were the main line of treatment therapy. However, the use of high-dose opioids has essentially replaced such procedures. Recognition of the limits of medical therapy to treat cancer pain effectively is growing, while conversely, in regions with limited access to pain medications, the importance of destructive surgical techniques is increasing. A critical evaluation of the evidence for destructive techniques is warranted, and the authors review current evidence underlying these procedures.

Methods

A US National Library of Medicine PubMed search for “ablation,” “DREZ,” “dorsal root entry zone,” “cingulotomy,” “cordotomy,” “ganglionectomy,” “mesencephalotomy,” “myelotomy,” “neurotomy,” “neurectomy,” “rhizotomy,” “sympathectomy,” “thalamotomy,” “tractotomy,” and “pain” was undertaken. The search was then limited to human studies, English-language literature, cancer pain, and reports with more than 1 patient.

Results

One hundred twenty papers were identified and reviewed based on the selection criteria described. According to the Canadian and US task forces, classification of clinical research literature only “sympathectomy” was supported by Class I or II studies, with 2 Class I papers and 1 Class II paper identified for cancer pain. All other procedures were supported by Class III studies of variable quality. Cordotomy in particular was the most extensively studied and reviewed procedure. Given the large number of patients studied, consistent results, multiplicity of reports and, even though evidence quality for individual studies was relatively low, cumulative evidence suggests that cordotomy may play an important role in the treatment of cancer pain.

Conclusions

Destructive procedures for cancer pain may play more than a historic role in the management of cancer pain. Cumulative evidence from even the poorest quality studies suggests that some procedures, such as cordotomy, should be included in the armamentarium available to the neurosurgeon today. To renew appropriate interest in these procedures, evidence and studies that meets today's evidence-based research criteria are warranted.

Deep brain stimulation does not silence neurons in subthalamic nucleus in Parkinson's patients

Two broad hypotheses have been advanced to explain the clinical efficacy of deep brain stimulation (DBS) in the subthalamic nucleus (STN) for treatment of Parkinson's disease. One is that stimulation inactivates STN neurons, producing a functional lesion. The other is that electrical stimulation activates the STN output, thus "jamming" pathological activity in basal ganglia-corticothalamic circuits. Evidence consistent with both concepts has been adduced from modeling and animal studies, as well as from recordings in patients. However, the stimulation parameters used in many recording studies have not been well matched to those used clinically. In this study, we recorded STN activity in patients with Parkinson's disease during stimulation delivered through a clinical DBS electrode using standard therapeutic stimulus parameters. A microelectrode was used to record the firing of a single STN neuron during DBS (3-5 V, 80-200 Hz, 90- to 200-micros pulses; 33 neurons/11 patients). Firing rate was unchanged during the stimulus trains, and the recorded neurons did not show prolonged (s) changes in firing rate on termination of the stimulation. However, a brief (approximately 1 ms), short-latency (6 ms) postpulse inhibition was seen in 10 of 14 neurons analyzed. A subset of neurons displayed altered firing patterns, with a predominant shift toward random firing. These data do not support the idea that DBS inactivates the STN and are instead more consistent with the hypothesis that this stimulation provides a null signal to basal ganglia-corticothalamic circuitry that has been altered as part of Parkinson's disease.