Saturday, March 30, 2013

Categorization = Decision Making + Generalization

Available online 30 March 2013
Publication year: 2013
Source:Neuroscience & Biobehavioral Reviews

We rarely, if ever, repeatedly encounter exactly the same situation. This makes generalization crucial for real world decision making. We argue that categorization, the study of generalizable representations, is a type of decision making, and that categorization learning research would benefit from approaches developed to study the neuroscience of decision making. Similarly, methods developed to examine generalization and learning within the field of categorization may enhance decision making research. We first discuss perceptual information processing and integration, with an emphasis on accumulator models. We then examine learning the value of different decision making choices via experience, emphasizing reinforcement learning modeling approaches. Next we discuss how value is combined with other factors in decision making, emphasizing the effects of uncertainty. Finally, we describe how a final decision is selected via thresholding processes implemented by the basal ganglia and related regions. We also consider how memory related functions in the hippocampus may be integrated with decision making mechanisms and contribute to categorization.






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Friday, March 29, 2013

Teamwork in skull base surgery: An avenue for improvement in patient care

Nancy McLaughlin, Ricardo L Carrau, Daniel F Kelly, Daniel M Prevedello, Amin B Kassam

Surgical Neurology International 2013 4(1):36-36

Background: During the past several decades, numerous centers have acquired significant expertise in the treatment of skull base pathologies. Favorable outcomes are not only due to meticulous surgical planning and execution, but they are also related to the collaborative efforts of multiple disciplines. We review the impact of teamwork on patient care, elaborate on the key processes for successful teamwork, and discuss its challenges. Methods: Pubmed and Medline databases were searched for publications from 1970 to 2012 using the following keywords: "teamwork", "multidisciplinary", "interdisciplinary", "surgery", "skull base", "neurosurgery", "tumor", and "outcome". Results: Current literature testifies to the complexity of establishing and maintaining teamwork. To date, few reports on the impact of teamwork in the management of skull base pathologies have been published. This lack of literature is somewhat surprising given that most patients with skull base pathology receive care from multiple specialists. Common factors for success include a cohesive and well-integrated team structure with well-defined procedural organization. Although a multidisciplinary work force has clear advantages for improving today's quality of care and propelling research efforts for tomorrow's cure, teamwork is not intuitive and requires training, guidance, and executive support. Conclusions: Teamwork is recommended to improve quality over the full cycle of care and consequently patient outcomes. Increased recognition of the value of an integrated team approach for skull base pathologies will hopefully encourage centers, physicians, allied health caregivers, and scientists devoted to treating these patients and advancing the field of knowledge to invest the time, effort, and resources to optimize and organize their collective expertise.





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Awake craniotomy for trapping a giant fusiform aneurysm of the middle cerebral artery

Emiliano Passacantilli, Giulio Anichini, Delia Cannizzaro, Francesca Fusco, Francesca Pedace, Jacopo Lenzi, Antonio Santoro

Surgical Neurology International 2013 4(1):39-39

Background: Giant fusiform aneurysms of the distal middle cerebral artery (MCA) are rare lesions that, because of the absence of an aneurysm neck and the presence of calcified walls and partial thrombosis, can be difficult to clip without sacrificing the parent vessel. Moreover, when the aneurysm is located in the dominant hemisphere, it is not possible to test language and cognitive functions during surgical intervention, making the closure of the parent vessel extremely dangerous. Case Description: A 46-year-old woman presented with a one-year history of frontal headache without neurological deficit. A magnetic resonance imaging and an angiography showed a giant fusiform aneurysm of the left M2 tract. Because of the location and the absence of a neck, the aneurysm was considered difficult to coil and not amenable to preoperative balloon occlusion; thus, the patient was a candidate for surgical treatment. After a preoperative psychological evaluation, patient underwent awake craniotomy with the asleep-awake-asleep technique. A standard left pterional approach was performed to expose the internal carotid artery, the MCA and the aneurysm originating from the frontal branch of the MCA. Neurological examination responses remained unchanged during temporary parent artery occlusion, and trapping was successfully performed. Conclusions: Awake craniotomy is a useful option in intracranial aneurysm surgery because it permits neurological testing before vessels are permanently clipped or sacrificed. With the asleep-awake-asleep technique, it is possible to perform a standard pterional craniotomy, which allows good exposure of the vascular structures without cerebral retraction.





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Most Physicians Concerned About Future of Profession

Nearly 6 in 10 physicians say they are concerned about the future of medicine, pointing to declining clinical autonomy and income.
Medscape Medical News





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Monday, March 25, 2013

A multi-disciplinary consensus statement concerning surgical approaches to low-grade, high-grade ast

Astrocytic tumors account for 42% of childhood brain tumors, arising in all anatomical regions and associated with neurofibromatosis type 1 (NF1) in 15%. Anatomical site determines the degree and risk of resectability; the more complete resection, the better the survival rates. New biological markers and modern radiotherapy techniques are altering the risk assessments of clinical decisions for tumor resection and biopsy. The increasingly distinct pediatric neuro-oncology multidisciplinary team (PNMDT) is developing a distinct evidence base.

A multidisciplinary consensus conference on pediatric neurosurgery was held in February 2011, where 92 invited participants reviewed evidence for clinical management of hypothalamic chiasmatic glioma (HCLGG), diffuse intrinsic pontine glioma (DIPG), and high-grade glioma (HGG). Twenty-seven statements were drafted and subjected to online Delphi consensus voting by participants, seeking >70% agreement from >60% of respondents; where <70% consensus occurred, the statement was modified and resubmitted for voting.

Twenty-seven statements meeting consensus criteria are reported. For HCLGG, statements describing overall therapeutic purpose and indications for biopsy, observation, or treatment aimed at limiting the risk of visual damage and the need for on-going clinical trials were made. Primary surgical resection was not recommended. For DIPG, biopsy was recommended to ascertain biological characteristics to enhance understanding and targeting of treatments, especially in clinical trials. For HGG, biopsy is essential, the World Health Organization classification was recommended; selection of surgical strategy to achieve gross total resection in a single or multistep process should be discussed with the PNMDT and integrated with trials based drug strategies for adjuvant therapies.








Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Site: www.neurocirurgiabr.com
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Treatment, prognostic factors, and outcomes in spinal cord astrocytomas

Background

Spinal astrocytomas are rare intramedullary CNS tumors for which there is limited consensus on treatment; the importance of the extent of resection (EOR), postoperative radiotherapy, and chemotherapy remains poorly understood. We report on outcomes associated with surgery, postoperative radiotherapy, and chemotherapy in a series of patients treated at M. D. Anderson Cancer Center (MDACC) with the aim of elucidating the role of these treatments in spinal astrocytomas.

Methods

We retrospectively reviewed charts from a series of 83 patients with histologically confirmed spinal astrocytoma treated at MDACC during 1990–2011. Data collected included patient demographic characteristics, prognostic indicators, and treatment modality at diagnosis. We analyzed overall survival (OS) and progression-free survival (PFS) for pilocytic (World Health Organization [WHO] grade I) and infiltrative (WHO grades II, III, and IV) astrocytomas, separately. Multivariate analysis was performed for the infiltrative patients but not the pilocytic patients because of a limited number of cases.

Results

Higher WHO grade among all patients was associated with worse OS (P < .0001) and PFS (P = .0003). Among patients with infiltrative tumors, neither EOR nor radiotherapy was associated with a difference in outcomes in multivariate analysis; however, among patients with infiltrative astrocytomas, chemotherapy was significantly associated with improved PFS (hazard ratio = .22, P = .0075) but not OS (hazard ratio = .89, P = .83) in multivariate analysis.

Conclusion

WHO grade was the strongest prognostic indicator in patients with spinal cord astrocytomas. Our results also show that chemotherapy improved PFS in infiltrative astrocytomas in multivariate analysis, but neither EOR nor radiation therapy influenced outcomes in this group.








Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Site: www.neurocirurgiabr.com
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Sunday, March 24, 2013

Transventricular Endoscopic Fenestration of Intrasellar Arachnoid Cyst

imageBACKGROUND: To manage arachnoid cysts, incorporation with the normal circulation is the single most important determinant of success. Although the postoperative cerebrospinal fluid leakage rate is 3.9% for all cases of transsphenoidal surgery, it is 21.4% for intrasellar arachnoid cysts. OBJECTIVE: To present a safe, relatively easy, and effective treatment option for very rare intrasellar arachnoid cysts. METHODS: We performed a prospective study of intrasellar cystic lesions without a solid portion. Endoscopic exploration and fenestration were performed for all lesions under neuronavigational guidance. We analyzed presenting symptoms, endocrinological status, and magnetic resonance images. RESULTS: There were 2 male and 4 female patients with a mean age of 45 years (range, 27-67 years). All patients presented with the visual disturbance of bitemporal hemianopsia. Four patients had endocrinological symptoms including galactorrhea, dysmenorrhea, and diabetes insipidus. Endoscopic fenestration of the cyst was successfully performed in all patients. All patients were confirmed to have a pure cystic lesion, namely an arachnoid cyst. The follow-up period was 10 months on average (range, 6-12 months). Visual disturbance improved in 5 patients. Endocrinological problems persisted in all patients for 3 months and then normalized, with the exception of the patient with diabetes insipidus. There was no evidence of recurrence in any of the 6 patients in the 12-month postoperative imaging studies (median follow-up of 10 months). Two patients showed syndrome of inappropriate antidiuretic hormone at 2 and 4 weeks after the operation, but antidiuretic hormones recovered to normal levels after this time point. CONCLUSION: Endoscopic fenestration of an intrasellar arachnoid cyst is a safe and simple procedure without serious complications. ABBREVIATIONS: IAC, intrasellar arachnoid cyst SPAC, suprasellar-prepontine arachnoid cyst







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
Linkedin:http://www.linkedin.com/in/juliommais 
Site: www.neurocirurgiabr.com
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Saturday, March 23, 2013

Neurosurgery App FREE - Android on Google Play #neurosurgery #medicine #medicina #neurocirurgia #neurology #neurologia


https://play.google.com/store/apps/details?id=com.sodavirtual.neurosurgery&feature=more_from_developer#?t=W251bGwsMSwxLDEwMiwiY29tLnNvZGF2aXJ0dWFsLm5ldXJvc3VyZ2VyeSJd

Latest news, researches and blog about Neurology, Neuroscience and Neurosurgery.
To provide neurosurgeons with the most timely comprehensive and relevant clinical information to improve patient care.
The mission of Neurosurgery blog is to facilitate the equitable, global dissemination of high-quality health research; to promote international dialogue and collaboration on health issues; to improve clinical practice; and to expand and deepen the understanding of health and health care.

Signed By:

Dr. Júlio Leonardo Barbosa Pereira - Neurosurgery Blog
Dr. Mauro Cruz Machado Borgo - Neurosurgery Blog e Neurocirurgia da Santa Casa de Barbacena
Dr. Lucas Alverne F. Albuquerque - Neurosurgery Blog e Residente de Neurocirurgia da Santa Casa de Belo Horizonte
Dr. José Lopes Filho - Neurosurgery Blog e Residente de Neurocirurgia da Santa Casa de Belo Horizonte
Dr. Gervásio Teles Cardoso de Carvalho (Assistente de Neurocirurgia da Santa Casa de Belo Horizonte e Faculdade de Ciências Médicas de MG)

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Friday, March 22, 2013

FREE Neuroinfect App (partial) #medicine #medlife #neurology #neurosurgery #health


Neuroinfect App
About infection disease. 




Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Site: www.neurocirurgiabr.com
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Thursday, March 21, 2013

A Phase 3 Trial of Whole Brain Radiation Therapy and Stereotactic Radiosurgery Alone Versus WBRT and

Background: A phase 3 Radiation Therapy Oncology Group (RTOG) study subset analysis demonstrated improved overall survival (OS) with the addition of stereotactic radiosurgery (SRS) to whole brain radiation therapy (WBRT) in non-small cell lung cancer (NSCLC) patients with 1 to 3 brain metastases. Because temozolomide (TMZ) and erlotinib (ETN) cross the blood-brain barrier and have documented activity in NSCLC, a phase 3 study was designed to test whether these drugs would improve the OS associated with WBRT + SRS.Methods and Materials: NSCLC patients with 1 to 3 brain metastases were randomized to receive WBRT (2.5 Gy × 15 to 37.5 Gy) and SRS alone, versus WBRT + SRS + TMZ (75 mg/m2/day × 21 days) or ETN (150 mg/day). ETN (150 mg/day) or TMZ (150-200 mg/m2/day × 5 days/month) could be continued for as long as 6 months after WBRT + SRS. The primary endpoint was OS.Results: After 126 patients were enrolled, the study closed because of accrual limitations. The median survival times (MST) for WBRT + SRS, WBRT + SRS + TMZ, and WBRT + SRS + ETN were qualitatively different (13.4, 6.3, and 6.1 months, respectively), although the differences were not statistically significant. Time to central nervous system progression and performance status at 6 months were better in the WBRT + SRS arm. Grade 3 to 5 toxicity was 11%, 41%, and 49% in arms 1, 2, and 3, respectively (P<.001).Conclusion: The addition of TMZ or ETN to WBRT + SRS in NSCLC patients with 1 to 3 brain metastases did not improve survival and possibly had a deleterious effect. Because the analysis is underpowered, these data suggest but do not prove that increased toxicity was the cause of inferior survival in the drug arms.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
Linkedin:http://www.linkedin.com/in/juliommais 
Site: www.neurocirurgiabr.com
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FDA Approves New Gadolinium-Based MRI Agent

The MRI contrast agent, already on the market in dozens of other countries, helps radiologists visualize abnormalities of the central nervous system.
FDA Approvals







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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FDA Approves New Gadolinium-Based MRI Agent

The MRI contrast agent, already on the market in dozens of other countries, helps radiologists visualize abnormalities of the central nervous system.
FDA Approvals







Júlio Leonardo B. Pereira
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Anti-Nausea Drug Destroys Brain Tumor Cells

New research from the University of Adelaide has shown for the first time that the growth of brain tumors can be halted by a drug currently being used to help patients recover from the side effects of chemotherapy. The discovery has been made during a study looking at the relationship between brain tumors and a peptide associated with inflammation in the brain, called "substance P"...







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Tuesday, March 19, 2013

Craniotomy App #neurosurgery #medicine #medschool #medlife #neurocirurgia

Craniotomy - Android Apps on Google Play
Step-by-Step Craniotomies ... 

Come soon for iPhone And iPad


Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
Linkedin:http://www.linkedin.com/in/juliommais 
Site: www.neurocirurgiabr.com
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Saturday, March 16, 2013

Researchers Predict Unfavorable Outcomes In Surgical Patients With Brain Tumor, Low T3

In a study of 90 patients undergoing surgery for brain tumor, researchers in Lithuania (Lithuanian University of Health Sciences) and the United States (University of North Carolina at Chapel Hill and Brigham & Women's Hospital, Harvard University) have discovered that the finding of low T3 (triiodothyronine) syndrome is predictive of unfavorable clinical outcomes and depressive symptoms...







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Site: www.neurocirurgiabr.com
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Coach: Anti-cancer gets personal

There are a lot of things I learned from my experience with pancreatic cancer. I realized that we all need to be more kind to each other.







Júlio Leonardo B. Pereira
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Scientists diagnose intestinal worms -- using an iPhone

In a discovery that provides doctors in remote areas with invaluable alternatives, scientists recently improvised a microscope using an iPhone, tape, flashlight and camera lens.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Tuesday, March 12, 2013

Cancer incidence and mortality patterns in Europe: Estimates for 40 countries in 2012

Available online 26 February 2013
Publication year: 2013
Source:European Journal of Cancer

Introduction Cancer incidence and mortality estimates for 25 cancers are presented for the 40 countries in the four United Nations-defined areas of Europe and for the European Union (EU-27) for 2012. Methods We used statistical models to estimate national incidence and mortality rates in 2012 from recently-published data, predicting incidence and mortality rates for the year 2012 from recent trends, wherever possible. The estimated rates in 2012 were applied to the corresponding population estimates to obtain the estimated numbers of new cancer cases and deaths in Europe in 2012. Results There were an estimated 3.45 million new cases of cancer (excluding non-melanoma skin cancer) and 1.75 million deaths from cancer in Europe in 2012. The most common cancer sites were cancers of the female breast (464,000 cases), followed by colorectal (447,000), prostate (417,000) and lung (410,000). These four cancers represent half of the overall burden of cancer in Europe. The most common causes of death from cancer were cancers of the lung (353,000 deaths), colorectal (215,000), breast (131,000) and stomach (107,000). In the European Union, the estimated numbers of new cases of cancer were approximately 1.4 million in males and 1.2 million in females, and around 707,000 men and 555,000 women died from cancer in the same year. Conclusion These up-to-date estimates of the cancer burden in Europe alongside the description of the varying distribution of common cancers at both the regional and country level provide a basis for establishing priorities to cancer control actions in Europe. The important role of cancer registries in disease surveillance and in planning and evaluating national cancer plans is becoming increasingly recognised, but needs to be further advocated. The estimates and software tools for further analysis (EUCAN 2012) are available online as part of the European Cancer Observatory (ECO) (http://eco.iarc.fr). 








Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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First Successful Blocking Of Tumor Development In A Genetic Mouse Model Of An Incurable Human Cancer

"To my knowledge, this is the first time that a mouse model of a genetically defined malignant human cancer has been generated in which the formation of the tumor from beginning to end can be monitored and in which blocking the pathway cures the mouse of the tumor," said Dr...







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Monday, March 11, 2013

Aspirin is associated with lower melanoma risk among postmenopausal Caucasian women

Abstract

BACKGROUND:

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with decreased risk of gastric, colorectal, and breast cancer. However, the impact of NSAIDs on the risk of melanoma has been inconsistent. The authors evaluated the association between NSAID use and cutaneous melanoma risk in the Women's Health Initiative (WHI) Observational Study (OS).

METHODS:

At study entry, use of aspirin (acetylsalicylic acid [ASA]) and nonaspirin NSAIDs was assessed among 59,806 postmenopausal Caucasian women ages 50 to 79 years. Cox proportional hazards models were constructed after adjusting for participant skin type, sun exposure history, and medical indications for NSAID use among other confounders.

RESULTS:

During a median follow-up of 12 years, 548 incident melanomas were confirmed by medical review. Women who used ASA had a 21% lower risk of melanoma (hazard ratio, 0.79; 95% confidence interval, 0.63-0.98) relative to nonusers. Increased duration of ASA use (<1 year, 1-4 years, and ≥5 years) was associated with an 11% lower risk of melanoma for each categorical increase (Ptrend = .01), and women with ≥5 years of use had a 30% lower melanoma risk (hazard ratio, 0.70; 95% confidence interval, 0.55-0.94). In contrast, use of non-ASA NSAIDs and acetaminophen were not associated with melanoma risk.

CONCLUSIONS:

Postmenopausal women who used ASA had a significantly lower risk of melanoma, and longer duration of ASA use was associated with greater protection. Although this study was limited by the observational design and self-report of NSAID use, the findings suggest that ASA may have a chemopreventive effect against the development of melanoma and warrant further clinical investigation. Cancer 2012. © 2012 American Cancer Society.








Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Wednesday, March 6, 2013

[News] Research shows four-stranded DNA in human cancer cells

Researchers have for the first time identified an increase in four-stranded G-quadruplex DNA structures at a crucial point in DNA replication in human cancer cells. These structures could be a new target for cancer drugs.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
Linkedin:http://www.linkedin.com/in/juliommais 
Site: www.neurocirurgiabr.com
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[Editorial] Quality and value in cancer care

In these times of stringent financial cuts, it is more important than ever to ensure excellent value for money in health-care delivery. Those that hold the purse strings might well think that value for money equates to the lowest cost. But true economy in health services incorporates quality and efficacy of treatment. For example, an effective therapy with a lower adverse event rate is likely to be more economical than is a lower-cost drug that requires more supportive care. Identifying a biological approach for a cancer treatment inevitably stimulates a race between pharmaceutical companies to bring a drug to market, often resulting in several agents that act against the same target, but with no evidence of their relative effectiveness.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
Linkedin:http://www.linkedin.com/in/juliommais 
Site: www.neurocirurgiabr.com
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Differentiation of local tumor recurrence from radiation-induced changes after stereotactic radiosur

Background: Structural follow-up magnetic resonance imaging (MRI) after stereotactic radiosurgery (SRS) for brain metastases frequently displays local changes in the area of applied irradiation, which are often difficult to interpret (e.g., local tumor recurrence, radiation-induced changes). The use of stereotactic biopsy for histological assessment of these changes has a high diagnostic accuracy and can be considered as method of choice. In order to solve this relevant clinical problem non-invasively, advanced MRI techniques and amino acid positron-emission-tomography (PET) are increasingly used.Case presentationWe report the long-term follow-up of a patient who had been treated with linear accelerator based SRS for cerebral metastases of a lung cancer. Fifty-eight months after SRS, the differentiation of local recurrent brain metastasis from radiation-induced changes using structural MRI was difficult. For further differentiation, perfusion-weighted MRI (PWI), proton magnetic resonance spectroscopy (MRS), and 11C-methyl-L-methionine (MET) PET was performed. Due to artifacts and technical limitations, PWI MRI and MRS findings were not conclusive. In contrast, MET PET findings were suggestive for radiation-induced changes. Finally, a stereotactic biopsy for histological assessment of these changes demonstrated clearly a radiation-induced necrosis and the absence of vital tumor. Conclusion: The use of stereotactic biopsy for histological assessment of indistinguishable lesions on structural MRI after SRS for treatment of brain metastasis represents a highly reliable method to differentiate local tumor recurrence from radiation-induced changes. In this field, results of studies with both advanced MRI techniques and amino acid PET suggest encouraging results. However, artifacts and technical limitations (e.g., lesion size) are still a problem and comparative studies are needed to investigate the relationship, diagnostic performance, and complementary character of advanced MRI techniques and amino acid PET.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
Linkedin:http://www.linkedin.com/in/juliommais 
Site: www.neurocirurgiabr.com
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Saturday, March 2, 2013

Endoscopic endonasal surgery for giant pituitary adenomas: advantages and limitations

Journal of Neurosurgery, Volume 118, Issue 3, Page 621-631, March 2013.
Object Giant pituitary adenomas (> 4 cm in maximum diameter) represent a significant surgical challenge. Endoscopic endonasal surgery (EES) has recently been introduced as a treatment option for these tumors. The authors present the results of EES for giant adenomas and analyze the advantages and limitations of this technique. Methods The authors retrospectively reviewed the medical files and imaging studies of 54 patients with giant pituitary adenomas who underwent EES and studied the factors affecting surgical outcome. Results Preoperative visual impairment was present in 45 patients (83%) and partial or complete pituitary deficiency in 28 cases (52%), and 7 patients (13%) presented with apoplexy. Near-total resection (> 90%) was achieved in 36 patients (66.7%). Vision was improved or normalized in 36 cases (80%) and worsened in 2 cases due to apoplexy of residual tumor. Significant factors that limited the degree of resection were a multilobular configuration of the adenoma (p = 0.002) and extension to the middle fossa (p = 0.045). Cavernous sinus invasion, tumor size, and intraventricular or posterior fossa extension did not influence the surgical outcome. Complications included apoplexy of residual adenoma (3.7%), permanent diabetes insipidus (9.6%), new pituitary insufficiency (16.7%), and CSF leak (16.7%, which was reduced to 7.4% in recent years). Fourteen patients underwent radiation therapy after EES for residual mass or, in a later stage, for recurrence, and 10 with functional pituitary adenomas received medical treatment. During a mean follow-up of 37.9 months (range 1–114 months), 7 patients were reoperated on for tumor recurrence. Three patients were lost to follow-up. Conclusions Endoscopic endonasal surgery provides effective initial management of giant pituitary adenomas with favorable results compared with traditional microscopic transsphenoidal and transcranial approaches.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Long-term hearing outcomes following stereotactic radiosurgery for vestibular schwannoma: patterns o

Journal of Neurosurgery, Volume 118, Issue 3, Page 579-587, March 2013.
Object The goals of this retrospective cohort study were as follows: 1) to describe the long-term prevalence and timing of hearing deterioration following low-dose (12- to 13-Gy marginal dose) stereotactic radiosurgery (SRS) for vestibular schwannoma (VS); and 2) to identify clinical variables associated with long-term preservation of useful hearing following treatment. Methods Patients with serviceable hearing who underwent SRS for VS between 1997 and 2002 were studied. Data including radiosurgery treatment plans, tumor characteristics, pre- and posttreatment pure tone average, speech discrimination scores, and American Academy of Otolaryngology–Head and Neck Surgery hearing class were collected. Time to nonserviceable hearing was estimated using the Kaplan-Meier method. Univariate and multivariate associations with time to nonserviceable hearing were evaluated using Cox proportional hazards regression models. Results Forty-four patients met the study criteria and were included. The median duration of audiometric follow-up was 9.3 years. Thirty-six patients developed nonserviceable hearing at a mean of 4.2 years following SRS. The Kaplan-Meier estimated rates of serviceable hearing at 1, 3, 5, 7, and 10 years following SRS were 80%, 55%, 48%, 38%, and 23%, respectively. Multivariate analysis revealed that pretreatment ipsilateral pure tone average (p < 0.001) and tumor size (p = 0.009) were statistically significantly associated with time to nonserviceable hearing. Conclusions Durable hearing preservation a decade after low-dose SRS for VS occurs in less than one-fourth of patients. Variables including preoperative hearing capacity and tumor size may be used to predict hearing outcomes following treatment. These findings may assist in pretreatment risk disclosure. Furthermore, these data demonstrate the importance of long-term follow-up when reporting audiometric outcomes following SRS for VS.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Hearing preservation in patients with vestibular schwannoma treated with Gamma Knife surgery

Journal of Neurosurgery, Volume 118, Issue 3, Page 571-578, March 2013.
Object Hearing loss after Gamma Knife surgery (GKS) in patients with vestibular schwannoma has been associated with radiation dose to the cochlea. The purpose of this study was to evaluate serviceable hearing preservation in patients with VS who were treated with GKS and to determine if serviceable hearing loss can be correlated with the dose to the cochlea. Methods Forty patients with vestibular schwannoma with serviceable hearing were treated using GKS with a median marginal dose of 12.5 Gy (range 12.5–13 Gy) to the 50% isodose volume. Audiometry was performed prospectively before and after GKS at 1, 3, and 6 months, and then every 6 months thereafter. Hearing preservation was based on pure tone average (PTA) and speech discrimination (SD). Serviceable hearing was defined as PTA less than 50 dB and SD greater than 50%. Results The median cochlear maximum and mean doses were 6.9 Gy (range 1.6–16 Gy) and 2.7 Gy (range 0.7–5.0 Gy), respectively. With a median audiological follow-up of 35 months (range 6–58 months), the 1-, 2-, and 3-year actuarial rates of maintaining serviceable hearing were 93%, 77%, and 74%, respectively. No patient who received a mean cochlear dose less than 2 Gy experienced serviceable hearing loss (p = 0.035). Patients who received a mean cochlear dose less than 3 Gy had a 2-year hearing preservation rate of 91% compared with 59% in those who received a mean cochlear dose of 3 Gy or greater (p = 0.029). Those who had more than 25% of their cochlea receiving 3 Gy or greater had a higher rate of hearing loss (p = 0.030). There was no statistically significant correlation between serviceable hearing loss and age, tumor size, pre-GKS PTA, pre-GKS SD, pre-GKS Gardner-Robertson class, maximum cochlear dose, or the percentage of cochlear volume receiving 5 Gy. On multivariate analysis there was a trend toward significance for serviceable hearing loss with a mean cochlear dose of 3 Gy or greater (p = 0.074). Local control was 100% at 24 months. No patient developed facial or trigeminal nerve dysfunction. Conclusions With a median mean cochlear dose of 2.7 Gy, the majority of patients with serviceable hearing retained serviceable hearing 3 years after GKS. A mean cochlear dose less than 3 Gy was associated with higher serviceable hearing preservation.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Long-term safety and efficacy of stereotactic radiosurgery for vestibular schwannomas: evaluation of

Journal of Neurosurgery, Volume 118, Issue 3, Page 557-565, March 2013.
Object Little is known about long-term outcomes, including tumor control and adverse radiation effects, in patients harboring vestibular schwannomas (VSs) treated with stereotactic radiosurgery > 10 years previously. The aim of this study was to confirm whether Gamma Knife surgery (GKS) for VSs continues to be safe and effective > 10 years after treatment. Methods A total of 440 patients with VS (including neurofibromatosis Type 2) treated with GKS between May 1991 and December 2000 were evaluable. Of these, 347 patients (79%) underwent GKS as an initial treatment and 93 (21%) had undergone prior resection. Three hundred fifty-eight patients (81%) had a solid tumor and 82 (19%) had a cystic tumor. The median tumor volume was 2.8 cm3 and the median marginal dose was 12.8 Gy. Results The median follow-up period was 12.5 years. The actuarial 5- and ≥ 10-year progression-free survival was 93% and 92%, respectively. No patient developed treatment failure > 10 years after treatment. According to multivariate analysis, significant factors related to worse progression-free survival included brainstem compression with a deviation of the fourth ventricle (p < 0.0001), marginal dose ≤ 13 Gy (p = 0.01), prior treatment (p = 0.02), and female sex (p = 0.02). Of 287 patients treated at a recent optimum dose of ≤ 13 Gy, 3 (1%) developed facial palsy, including 2 with transient palsy and 1 with persistent palsy after a second GKS, and 3 (1%) developed facial numbness, including 2 with transient and 1 with persistent facial numbness. The actuarial 10-year facial nerve preservation rate was 97% in the high marginal dose group (> 13 Gy) and 100% in the low marginal dose group (≤ 13 Gy). Ten patients (2.3%) developed delayed cyst formation. One patient alone developed malignant transformation, indicating an incidence of 0.3%. Conclusions In this study GKS was a safe and effective treatment for the majority of patients followed > 10 years after treatment. Special attention should be paid to cyst formation and malignant transformation as late adverse radiation effects, although they appeared to be rare. However, it is necessary to collect further long-term follow-up data before making conclusions about the long-term safety and efficacy of GKS, especially for young patients with VSs.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Prognosis by tumor location in adults with spinal ependymomas

Journal of Neurosurgery: Spine, Volume 18, Issue 3, Page 226-235, March 2013.
Object Ependymomas are primary central nervous system tumors that occur more frequently in the spines of adults than they do there in children. Previous studies consist mainly of retrospective single-institutional experiences or case studies. In this study, a comprehensive literature review was performed on reported cases of spinal ependymoma treated with resection to determine whether tumor location along the spinal axis conveys important prognostic information. Methods A PubMed search was performed to identify all papers that included data on patients with spinal ependymoma. Only cases involving adult patients who underwent ependymoma resection with a clearly reported tumor location were included for analysis. Tumor locations were separated into 6 groups: cervicomedullary, cervical, cervicothoracic, thoracic, thoracolumbar, and conus + cauda equina. Kaplan-Meier survival and Cox regression analyses were performed to determine the effect of tumor location on progression-free survival (PFS) and overall survival (OS). Results A total of 447 patients who underwent resection of spinal ependymomas with clearly indicated location of tumor were identified. The most common locations of spinal ependymomas were the cervical (32.0%) and conus + cauda equina (26.8%) regions. The thoracolumbar and cervicomedullary regions had the fewest tumors (accounting for, respectively, 5.1% and 3.4% of the total number of cases). The conus + cauda equina and thoracolumbar regions had the highest percentage of WHO Grade I tumors, while tumors located above these regions consisted of mostly WHO Grade II tumors. Despite the tendency for benign grades in the lower spinal regions, PFS for patients with spinal ependymomas in the lower 3 regions (thoracic, thoracolumbar, conus + cauda equina) was significantly shorter (p < 0.001) than for those with tumors in the upper regions (cervicomedullary, cervical, cervicothoracic), but the difference in OS did not achieve statistical significance (p = 0.131). Conclusions Spinal ependymomas along different regions of spinal axis have different characteristics and clinical behaviors. Tumor grade, extent of resection, and PFS varied by tumor location (upper vs lower spinal regions), while OS did not. Recurrence rates were higher for the lower spinal cord tumors, despite a greater prevalence of lower WHO grade lesions, compared with upper spinal cord tumors, suggesting that tumor location along the spinal axis is an important prognostic factor.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Management and outcome of focal low-grade brainstem tumors in pediatric patients: the St. Jude exper

Journal of Neurosurgery: Pediatrics, Volume 11, Issue 3, Page 274-281, March 2013.
Object Whereas diffuse intrinsic pontine gliomas generally have a short symptom duration and more cranial nerve involvement, focal brainstem gliomas are commonly low grade, with fewer cranial neuropathies. Although these phenotypic distinctions are not absolute predictors of outcome, they do demonstrate correlation in most cases. Because there is a limited literature on focal brainstem gliomas in pediatric patients, the objective of this paper was to report the management and outcome of these tumors. Methods The authors reviewed the records of all children diagnosed with radiographically confirmed low-grade focal brainstem gliomas from 1986 to 2010. Each patient underwent biopsy or resection for tissue diagnosis. Event-free survival (EFS) and overall survival were evaluated. Univariate analysis was conducted to identify demographic and treatment variables that may affect EFS. Results Fifty-two patients (20 girls, 32 boys) with follow-up data were identified. Median follow-up was 10.0 years, and the median age at diagnosis was 6.5 years (range 1–17 years). The tumor locations were midbrain (n = 22, 42%), pons (n = 15, 29%), and medulla (n = 15, 29%). Surgical extirpation was the primary treatment in 25 patients (48%). The 5- and 10-year EFS and overall survival were 59%/98% and 52%/90%, respectively. An event or treatment failure occurred in 24 patients (46%), including 5 deaths. Median time to treatment failure was 3.4 years. Disease progression in the other 19 patients transpired within 25.1 months of diagnosis. Thirteen of these patients received radiation, including 11 within 2 months of primary treatment failure. Although children with intrinsic tumors had slightly better EFS at 5 years compared with those with exophytic tumors (p = 0.054), this difference was not significant at 10 years (p = 0.147). No other variables were predictive of EFS. Conclusions Surgery suffices in many children with low-grade focal brainstem gliomas. Radiation treatment is often reserved for disease progression but offers comparable disease control following biopsy. In the authors' experience, combining an assessment of clinical course, imaging, and tumor biopsy yields a reasonable model for managing children with focal brainstem tumors.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Neurosurgical treatment of low-grade cerebellar astrocytoma in children and adolescents: a single co

Journal of Neurosurgery: Pediatrics, Volume 11, Issue 3, Page 245-249, March 2013.
Object The objective of this study was to delineate the long-term results of surgical treatment of pediatric low-grade cerebellar astrocytoma. Methods One hundred consecutive children and adolescents (0–19 years old) who underwent primary tumor resection for a low-grade cerebellar astrocytoma during the years 1980–2011 were included in this retrospective study on surgical morbidity, mortality rate, academic achievement, and/or work participation. Gross motor function and activities of daily living were scored according to the Barthel Index. Results Of the 100 patients, 61 children were in the 1st decade, and 39 were 10–19 years old. The male/female ratio was 1.13:1 (53 males, 47 females). No patients were lost to follow-up. There were no deaths in this series and all 100 patients are currently alive. In 29 patients, the follow-up duration was less than 10 years, in 37 it was between 10 and 19 years, and in 34 it was between 20 and 31 years. The Barthel Index was 100 (normal) in 97 patients, 90 in 2 patients, and 40 in the last patient. A total of 113 tumor resections were performed. Two patients underwent further tumor resection due to MRI-confirmed residual tumor demonstrated on the immediate postoperative MR image (obtained the day after the initial procedure). Furthermore, 9 children underwent repeat tumor resection after MRI-confirmed progressive tumor recurrence up to 10 years after the initial operation. Two of these patients also underwent a third resection, without subsequent radiation therapy, and have experienced 8 and 12 years of tumor-free follow-up thereafter, respectively. A total of 15% of the patients required treatment for persistent hydrocephalus. Conclusions Low-grade cerebellar astrocytoma is a surgical disease, in need of long-term follow-up, but with excellent long-term results. Nine percent of the children in this study underwent repeated surgery due to progressive tumor recurrence, and 15% were treated for persistent hydrocephalus.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Endoscopic endonasal skull base surgery in the pediatric population

Journal of Neurosurgery: Pediatrics, Volume 11, Issue 3, Page 227-241, March 2013.
Object The use of endoscopic endonasal surgery (EES) for skull base pathologies in the pediatric population presents unique challenges and has not been well described. The authors reviewed their experience with endoscopic endonasal approaches in pediatric skull base surgery to assess surgical outcomes and complications in the context of presenting patient demographics and pathologies. Methods A retrospective review of 133 pediatric patients who underwent EES at our institution from July 1999 to May 2011 was performed. Results A total of 171 EESs were performed for skull base tumors in 112 patients and bony lesions in 21. Eighty-five patients (63.9%) were male, and the mean age at the time of surgery was 12.7 years (range 2.3–18.0 years). Skull base tumors included angiofibromas (n = 24), craniopharyngiomas (n = 16), Rathke cleft cysts (n = 12), pituitary adenomas (n = 11), chordomas/chondrosarcomas (n = 10), dermoid/epidermoid tumors (n = 9), and 30 other pathologies. In total, 19 tumors were malignant (17.0%). Among patients with follow-up data, gross-total resection was achieved in 16 cases of angiofibromas (76.2%), 9 of craniopharyngiomas (56.2%), 8 of Rathke cleft cysts (72.7%), 7 of pituitary adenomas (70%), 5 of chordomas/chondrosarcomas (50%), 6 of dermoid/epidermoid tumors (85.7%), and 9 cases of other pathologies (31%). Fourteen patients received adjuvant radiotherapy, and 5 received chemotherapy. Sixteen patients (15.4%) showed tumor recurrence and underwent reoperation. Bony abnormalities included skull base defects (n = 12), basilar invagination (n = 4), optic nerve compression (n = 3) and trauma (n = 2); preexisting neurological dysfunction resolved in 12 patients (57.1%), improved in 7 (33.3%), and remained unchanged in 2 (9.5%). Overall, complications included CSF leak in 14 cases (10.5%), meningitis in 5 (3.8%), transient diabetes insipidus in 8 patients (6.0%), and permanent diabetes insipidus in 12 (9.0%). Five patients (3.8%) had transient and 3 (2.3%) had permanent cranial nerve palsies. The mean follow-up time was 22.7 months (range 1–122 months); 5 patients were lost to follow-up. Conclusions Endoscopic endonasal surgery has proved to be a safe and feasible approach for the management of a variety of pediatric skull base pathologies. When appropriately indicated, EES may achieve optimal outcomes in the pediatric population.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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Supratentorial Ependymoma: Disease Control, Complications, and Functional Outcomes After Irradiation

Purpose: Ependymoma is less commonly found in the supratentorial brain and has known clinical and molecular features that are unique. Our single-institution series provides valuable information about disease control for supratentorial ependymoma and the complications of supratentorial irradiation in children.Methods and Materials: A total of 50 children with newly diagnosed supratentorial ependymoma were treated with adjuvant radiation therapy (RT); conformal methods were used in 36 after 1996. The median age at RT was 6.5 years (range, 1-18.9 years). The entire group was characterized according to sex (girls 27), race (white 43), extent of resection (gross-total 46), and tumor grade (anaplastic 28). The conformal RT group was prospectively evaluated for neurologic, endocrine, and cognitive effects.Results: With a median follow-up time of 9.1 years from the start of RT for survivors (range, 0.2-23.2 years), the 10-year progression-free and overall survival were 73% + 7% and 76% + 6%, respectively. None of the evaluated factors was prognostic for disease control. Local and distant failures were evenly divided among the 16 patients who experienced progression. Eleven patients died of disease, and 1 of central nervous system necrosis. Seizure disorders were present in 17 patients, and 4 were considered to be clinically disabled. Clinically significant cognitive effects were limited to children with difficult-to-control seizures. The average values for intelligence quotient and academic achievement (reading, spelling, and math) were within the range of normal through 10 years of follow-up. Central hypothyroidism was the most commonly treated endocrinopathy.Conclusion: RT may be administered with acceptable risks for complications in children with supratentorial ependymoma. These results suggest that outcomes for these children are improving and that complications may be limited by use of focal irradiation methods.







Júlio Leonardo B. Pereira
Phone: (+1) 424-2301706
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