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Dive into the research topics where Siviero Agazzi is active.

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Featured researches published by Siviero Agazzi.


Neurosurgical Focus | 2009

Surgical management of moyamoya disease: a review.

Ali A. Baaj; Siviero Agazzi; Zafar A. Sayed; Maria Toledo; Robert F. Spetzler; Harry R. van Loveren

Moyamoya disease (MMD) is a progressive, occlusive disease of the distal internal carotid arteries associated with secondary stenosis of the circle of Willis. Symptoms include ischemic infarcts in children and hemorrhages in adults. Bypass of the stenotic vessel(s) is the primary surgical treatment modality for MMD. Superficial temporal artery-to-middle cerebral artery bypass is the most common direct bypass method. Indirect techniques rely on the approximation of vascularized tissue to the cerebral cortex to promote neoangiogenesis. This tissue may be in the form of muscle, pericranium, dura, or even omentum. This review highlights the surgical options available for the treatment of MMD.


Stroke | 2011

Paradoxical Trends in the Management of Unruptured Cerebral Aneurysms in the United States: Analysis of Nationwide Database Over a 10-Year Period

Michael C. Huang; Ali A. Baaj; Katheryne Downes; A. Samy Youssef; Eric Sauvageau; Harry R. van Loveren; Siviero Agazzi

Background and Purpose— The objective of this study was to characterize demographics, treatments, and outcomes in the management of unruptured cerebral aneurysms in the United States using a national healthcare database. Methods— Clinical data were derived from the Nationwide Inpatient Sample for the years 1997 through 2006. Patients with unruptured cerebral aneurysms were identified using the appropriate International Classification of Diseases, 9th Revision code (437.3). Hospitalizations, length of stay, hospital charges, discharge pattern, age and gender distribution, and nature of intervention were analyzed. A Bureau of Labor statistics tool was used to adjust hospital and national charges for inflation. Population-adjusted rates were calculated using population estimates generated by the US Census Bureau. Results— Over 100 000 records were retrieved for analysis. During the time period studied, there was a 75% increase in the number of hospitalizations associated with unruptured cerebral aneurysms. Inflation adjusted hospital charges increased by 60%, whereas the total national bill increased by 200%. Overall, length of stay decreased by 37% and in-hospital mortality rates decreased by 54%. The increasing number of hospitalizations and total national charges related to inpatient treatment of unruptured aneurysms were significantly associated with endovascular treatment rather than surgical clipping. Conclusions— Despite recent studies suggesting a low risk of rupture of incidentally diagnosed cerebral aneurysms, data from this study suggest an increasing trend of treatment for this entity in the United States. Furthermore, endovascular intervention is now the major driving force behind the increasing overall national charges. Given the current healthcare climate, the impact of these trends warrants discussion and debate.


Operative Neurosurgery | 2005

Transcranial surgery for pituitary adenomas.

A. Samy Youssef; Siviero Agazzi; Harry R. van Loveren

ALTHOUGH THE TRANSSPHENOIDAL approach is the preferred approach to the vast majority of pituitary tumors with or without suprasellar extension, the transcranial approach remains a vital part of the neurosurgical armamentarium for 1 to 4% of these tumors. The transcranial approach is effective when resection becomes necessary for a portion of a pituitary macroadenoma that is judged to be inaccessible from the transsphenoidal route because of isolation by a narrow waist at the diaphragma sellae, containment within the cavernous sinus lateral to the carotid artery, projection anteriorly onto the planum sphenoidale, or projection laterally into the middle fossa. The application of a transcranial approach in these circumstances may still be mitigated by response to prolactin inhibition of prolactinomas, the frequent lack of necessity to remove asymptomatic nonsecretory adenomas from the cavernous sinus, and the lack of evidence that sustained chemical cures can be reliably achieved by removal of secretory adenomas (adrenocorticotropic hormone, growth hormone) from the cavernous sinus. Cranial base surgical techniques have refined the surgical approach to pituitary adenomas but have had less effect on actual surgical indications than anticipated. Because application of the transcranial approach to pituitary adenomas is and should be rare in clinical practice, it is useful to standardize the technique to a default mode with which the surgical team is most experienced and, therefore, most comfortable. Our default mode for transcranial pituitary surgery is the frontotemporal-orbitozygomatic approach.


Journal of Neurosurgery | 2010

The safety and effectiveness of a dural sealant system for use with nonautologous duraplasty materials

Jason S. Weinstein; Kenneth C. Liu; Johnny B. Delashaw; Kim J. Burchiel; Harry R. van Loveren; Fernando L. Vale; Siviero Agazzi; Mark S. Greenberg; Donald A. Smith; John M. Tew

OBJECT The DuraSeal dural sealant system, a polyethylene glycol hydrogel, has been shown to be safe and effective when used with commercial and autologous duraplasty materials. The authors report on the safety and effectiveness of this sealant when used in conjunction with nonautologous duraplasty materials. METHODS In this retrospective, nonrandomized, multicenter study, the safety and efficacy of a dural sealant system was assessed in conjunction with primarily collagen-based nonautologous duraplasty materials in a sample of 66 patients undergoing elective cranial procedures at 3 institutions. This cohort was compared with 50 well-matched patients from the DuraSeal Pivotal Trial who were treated with this sealant system and autologous duraplasty material. RESULTS The key end points of the study were the incidences of CSF leaks, surgical site infections, and meningitis 90 days after surgery. The incidence of postoperative CSF leakage was 7.6% in the study group (retrospective population) and 6.0% in the Pivotal Trial population. The incidence of meningitis was 0% and 4.0% in the retrospective and Pivotal Trial groups, respectively. There were no serious device-related adverse events or unanticipated adverse device effects noted for either population. CONCLUSIONS This study demonstrates that the DuraSeal sealant system is safe and effective when used for watertight dural closure in conjunction with nonautologous duraplasty materials.


Neurosurgery | 2010

Insertion of intracranial pressure monitors in fulminant hepatic failure patients: early experience using recombinant factor VII.

Tien V. Le; Mark J. Rumbak; Shih Sing Liu; Angel E. Alsina; Harry R. van Loveren; Siviero Agazzi

BACKGROUNDCerebral edema contributes to the high morbidity and mortality of fulminant hepatic failure (FHF). OBJECTIVEWe report the results of our early experience with insertion of intraparenchymal intracranial pressure (ICP) monitors in these highly coagulopathic patients. METHODSEleven consecutive patients with FHF met the criteria for invasive ICP monitoring. Recombinant activated factor VII (rFVIIa) was administered at an average dose of 3 mg intravenous bolus (average, 36.7 μg/kg). We inserted the intraparenchymal ICP monitor within 15 minutes to 2 hours after rFVIIa administration, without waiting for the repeat coagulation results. Postprocedure computed tomographic scans of the brain were obtained in all patients. RESULTSNo hemorrhagic complications were detected on the immediate postprocedure computed tomographic scans. There were no thrombotic complications in this group of patients. CONCLUSIONIn this group of patients with FHF, placement of an ICP monitor without hemorrhagic or thrombotic complications was feasible after administration of rFVIIa. This is a report of our early experience, and caution is advised. Further collaborative randomized studies are needed to prove the efficacy, optimal dosing, and cost effectiveness of rFVIIa for the placement of ICP monitors in this group of patients.


Journal of Neurosurgery | 2012

Paradoxical trends in the management of vestibular schwannoma in the United States

Tsz Lau; Raul Olivera; Timothy Miller; Katheryne Downes; Christopher Danner; Harry R. van Loveren; Siviero Agazzi

OBJECT Recent natural history studies of vestibular schwannomas (VSs) suggest that most of these tumors do not grow. The impact of these new data on management trends in the US is currently unknown. The aim in the present study was to evaluate current trends in the treatment of VS in the US by analyzing a national cancer database. METHODS The Surveillance, Epidemiology, and End Results Program is a national database maintained by the National Cancer Institute representing 26% of the US population. Data from the database were downloaded using provided software. Cases were isolated based on histology codes and the site code. Data from 2004 to 2007 were included in the analysis. The number of patients undergoing resection was compared with the number treated with beam radiation and observation, based on tumor size. RESULTS Three thousand six hundred fifty cases were identified in the database. Over the study period, management choices for VSs showed a significant change only for tumors with a diameter < 2 cm. In this tumor category, a decrease in resection and an increase in radiation were observed, with observation showing a modest increase but remaining low at an average of 25%. CONCLUSIONS Study data demonstrated a shift in the management of small VSs in the US between 2004 and 2007, with microsurgical removal giving way to radiation treatment and the overall rate for observation remaining low and stable. With recent literature suggesting that the majority of small tumors do not grow, the authors assert that VSs are being overtreated in the US.


British Journal of Neurosurgery | 2014

The changing face of acoustic neuroma management in the USA: Analysis of the 1998 and 2008 patient surveys from the acoustic neuroma association

Jaymin Patel; Rohit Vasan; Harry R. van Loveren; Katheryne Downes; Siviero Agazzi

Abstract Objective. A recent review of the national cancer center registry Surveillance Epidemiology and End Results (SEER) database revealed that in the United States, 25% of Acoustic Neuromas (AN) are managed with observation. Several articles have questioned the aggressive treatment of these slow growing tumors. Concern has been raised that data from the SEER database might be biased towards treatment as patients who chose observation are less likely to be seen at a cancer center. To try and adjust for this potential bias, we decided to investigate management trends of AN in the United States using patient surveys conducted by the Acoustic Neuroma Association (ANA). Study design. Database review. Methods. Data from the 1998 and 2008 ANA patients surveys were analyzed to detect trends between tumor size and treatment modality. Management trends including observation, microsurgical resection and radiation were examined as well based on tumor size criteria. Results. During this study period, tumor size at diagnosis decreased significantly (1966–1998: 23.8% ≤ 1.5 cm; 1999–2008: 45.3% ≤ 1.5 cm). The use of microsurgery decreased from 92.7% to 53.4%, while the use of radiosurgery/radiotherapy increased from 5% to 24.2% and observation increased to 22.4%. Conclusion. Review of data from the ANA confirmed that radiosurgery, and watch and wait are gaining popularity as treatment options. Regardless of this shift in tumor management, microsurgery continues to be the primary method of treatment across tumor sizes in the United States of America and observation remains the least common management modality.


Neurosurgery | 2014

Surgical management of trigeminal neuralgia: use and cost-effectiveness from an analysis of the Medicare Claims Database.

Sananthan Sivakanthan; Jamie J. Van Gompel; Puya Alikhani; Harry R. van Loveren; Ren Chen; Siviero Agazzi

BACKGROUND Trigeminal neuralgia is a relatively common neurosurgical pathology with multiple management options. Microvascular decompression (MVD) is nonablative and is considered the gold standard. However, stereotaxic radiosurgery (SRS) and percutaneous stereotaxic rhizotomy (PSR) are 2 noninvasive but ablative options that have rapidly gained support. OBJECTIVE To use Medicare claims data in conjunction with a literature review to assess the usage, effectiveness, and cost-effectiveness of the 3 different invasive treatments for trigeminal neuralgia. METHODS All of the claims of trigeminal neuralgia treatment were extracted from the 2011 5% Inpatient and Outpatient Limited Data Set. Current Procedural Terminology, 4th Edition/International Classification of Diseases, Ninth Revision codes for the 3 different surgical treatment modalities were used to further classify these claims. Kaplan-Meier survival curves in key articles were used to calculate quality-adjusted life years and cost-effectiveness for each procedure. RESULTS A total of 1582 claims of trigeminal neuralgia were collected. Ninety-four (6%) patients underwent surgical intervention. Forty-eight (51.1%) surgical patients underwent MVD, 39 (41.5%) underwent SRS, and 7 (7.4%) underwent PSR. The average weighted costs for MVD, SRS, and PSR were


Neurosurgical Focus | 2009

Graft selection in cerebral revascularization.

Ali A. Baaj; Siviero Agazzi; Harry R. van Loveren

40 434.95,


Acta Neurochirurgica | 2004

The origin of brain metastases in patients with an undiagnosed primary tumour

Siviero Agazzi; S. Pampallona; A. Pica; O. Vernet; Luca Regli; François Porchet; Jean-Guy Villemure; S. Leyvraz

38 062.27, and

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A. Samy Youssef

University of South Florida

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Ramsey Ashour

University of South Florida

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Katheryne Downes

University of South Florida

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Puya Alikhani

University of South Florida

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Rohit Vasan

University of South Florida

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Tsz Lau

University of South Florida

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