A Modified Method for Creating Elastase-Induced Aneurysms by Ligation of Common Carotid Arteries in Rabbits and Its Effect on Surrounding Arteries.

BACKGROUND AND PURPOSE: Rabbit models of intracranial aneurysms are frequently used in pre-clinical settings. This study aimed to demonstrate an alternative, extravascular method for creating elastase-induced aneurysms, and how ligation of the right common carotid arteries (RCCA) can impact flow redistribution into left CCA (LCCA). METHODS: Elastase-induced aneurysms in 18 New Zealand rabbits (4.14 ± 0.314 kg) were created by applying 3-5 U of concentrated elastase solution to the exterior of the right and left CCA roots (RCCA and LCCA). After the induction of the aneurysm, the aneurysm was either kept intact to the rest of the corresponding CCA, severed from the rest of the CCA to allow for a free standing aneurysm, or was anchored to nearby tissue to influence the angle and orientation of the aneurysm with respect to the parent vessel. Ultrasound studies were performed before and after creation of aneurysms to collect blood flow measurements inside the aneurysm pouch and surrounding arteries. Prior to sacrificing the animals, computed tomography angiography studies were performed. Harvested aneurysmal tissues were used for histological analysis. RESULTS: Elastase-induced aneurysms were successfully created by the extravascular approach. Histological studies showed that the biological response was similar to human cerebral aneurysms and previously published elastase-induced rabbit aneurysm models. Ultrasound measurements indicated that after the RCCA was ligated, blood flow significantly increased in the LCCA at one-month follow-up. CONCLUSION: An alternate method for creating elastase-induced aneurysms has been demonstrated. The novel aspects of our method allow for ligation of one or both common carotid arteries to create a single or bilateral aneurysm with an ability to control the orientation of the induced aneurysm.

Spontaneous frontal intradiploic meningoencephalocele.

BACKGROUND: Since 1976, 10 cases of intradiploic encephaloceles have been reported in the literature. This case is the first report of a spontaneous intradiploic meningoencephalocele of the frontal bone hypothesized to be secondary to distant head trauma. CASE DESCRIPTION: A 60-year-old female with a history of multiple traumatic head injuries as a child presenting with new onset generalized tonic-clonic seizures. Work-up revealed a right frontal epileptic focus. Imaging showed a right frontal intradiploic lesion. The patient underwent surgical resection, which during exploration was found to be an intradiploic encephalocele. She had an uneventful postoperative course with a resolution of seizures. CONCLUSIONS: The authors hypothesize that the rare nature of posttraumatic frontal intradiploic encephaloceles is due to the increased thickness of the frontal bone compared to the parietal bone.

Preprocedure change in arterial occlusion in acute ischemic stroke patients undergoing endovascular treatment by computed tomographic angiography.

BACKGROUND: The American Heart Association/American Stroke Association guidelines strongly recommend a noninvasive intracranial vascular study such as computed tomographic (CT) angiogram in acute stroke patient if endovascular treatment is contemplated. OBJECTIVE: The objective was to determine the frequency of change in occlusion site between CT angiogram and cerebral angiogram in acute ischemic stroke patients undergoing endovascular treatment. METHODS: All acute ischemic stroke patients who underwent a CT angiogram and subsequently underwent endovascular treatment were included. The CT and cerebral angiographic images were reviewed independently to determine presence and location of arterial occlusion. Severity of occlusion was classified by a previously described grading scheme. Clinical outcome at discharge was determined using modified Rankin scale. RESULTS: Computed tomographic angiogram was performed in 150 patients (mean age ± SD, 64.7 ± 16 years) before endovascular treatment. The mean interval (±SD) between CT angiogram and cerebral angiogram was 193 ± 164 minutes, and 65 (43.3%) of 150 patients received intravenous recombinant tissue plasminogen activator before cerebral angiography. Recanalization between CT angiogram and cerebral angiography was seen in 28 (18.7%) patients, whereas worsening of occlusion was seen in 31 (20.7%) patients. We noticed a trend towards higher rates of improvement (60.7% vs 42.0%, P = .07) and favorable outcome at discharge (42.9% vs 28.7%, P = .1) among patients who experienced preprocedure recanalization. After adjusting for age and initial National Institutes of Health Stroke Scale score strata, preprocedure recanalization was not associated with significantly higher rate of favorable outcome (modified Rankin scale, 0-2) at discharge (odds ratio, 2.1; 95% confidence interval, 0.8-5.5). After adjusting for age and National Institutes of Health Stroke Scale score strata, preprocedure worsening was not associated with significantly lower rates of favorable outcomes at discharge (odds ratio,0.4; 95% confidence interval, 0.1-1.4). CONCLUSIONS: A relatively high proportion of patients have preprocedure recanalization or worsening between CT angiogram and cerebral angiogram in acute ischemic stroke patients selected for endovascular treatment.

Unsustainable hospital charges are incurred in the treatment of Medicare beneficiaries admitted with subarachnoid hemorrhage.

INTRODUCTION: Rising medical care expenditures and the unchanging Medicare reimbursements have placed restraints on the health care delivery system. OBJECTIVE: The goal of this study is to identify the magnitude and determinants of discrepancy between hospitalization charges and Medicare re-imbursement observed in the management of Medicare beneficiaries admitted with aneurysmal subarachnoid hemorrhage in the United States. METHODS: Patients entered in the Nationwide Inpatient Sample between 2002 and 2010, with a ruptured intracranial aneurysm who underwent either surgical or endovascular treatment were included in the study. Factors associated with higher discrepancy between hospitalization charges and Medicare re-imbursement were identified. RESULTS: Discrepancies in hospital charges and Medicare reimbursement associated with endovascular and surgical treatment have increased over the decade. The median discrepancy per patient for Medicare patients aged 65 years and older treated surgically or endovascularly for a ruptured aneurysm from 2009 to 2010 was $177,380. The predictors of higher than median discrepancy(charges versus reimbursement), included Hispanic ethnicity (OR 2.1, 95% CI 1.1-3.9, p = 0.02), urinary tract infection (OR 2.0, 95% CI 1.4-2.8, p = <0.001), pneumonia (OR 3.0, 95% CI 1.8-4.8, p = <0.001), deep vein thrombosis (OR 2.5, 95% CI 1.2-5.2, p = 0.02), and pulmonary embolism (OR 18, 95% CI 2.0-169, pp = 0.01). CONCLUSIONS: There is a growing gap between hospital charges and Medicare reimbursement. If hospitals continue to be reimbursed at significantly lower rates than charges incurred, this current system may be unsustainable due to losses incurred by hospitals. ABBREVIATIONS: AHRQAgency for Healthcare Research and QualityCMSCenters for Medicare and Medicaid servicesNISNationwide Inpatient Sample.

The emergence of endovascular treatment-only centers for treatment of intracranial aneurysms in the United States.

BACKGROUND: Because of the availability of new technology, the spectrum of endovascular treatment for intracranial aneurysms has expanded widely. Some centers have started offering only endovascular treatment to patients with intracranial aneurysms (endovascular treatment-only centers [ETOCs]). Our objective was to identify the proportion and outcome of patients treated at ETOCs in the United States. METHODS: We determined the proportion of ETOCs in the United States using Nationwide Inpatient Survey data files from 2010. We compared short-term outcomes between ETOCs and endovascular and surgical treatment centers (ESTCs). The outcomes studied were none to minimal disability, moderate to severe disability, in-hospital mortality, postprocedure complications, length of stay, and hospital charges. RESULTS: Out of 85 hospitals performing endovascular treatment of unruptured aneurysms, 13 (15%) were categorized as ETOCs. Out of the 10,447 patients with unruptured aneurysms, 1245 (12%) were treated at ETOCs. ETOCs were more likely to be nonteaching hospitals (55% versus 45%, P=.02). The rates of in-hospital mortality (1.2% versus 1.8%) and none to minimal disability (88% versus 84%) were similar in patients treated at ETOCs and ESTC hospitals. The mean hospitalization charges were similar, but length of stay (4±7 days versus 6±10 days, P<.0001) was significantly shorter among patients treated at ETOCs. Only 2.7% patients required secondary neurosurgical procedures at the ETOCs compared with 5.8% in ESTCs (P=.09). CONCLUSION: The recent emergence of ETOCs and provision of treatment with comparable outcomes and shorter length of stay at these hospitals may change the pattern of intracranial aneurysm treatment in the United States.

Epidemiological and clinical features of moyamoya disease in the USA.

BACKGROUND: An increasing number of cases of Moyamoya disease have been reported in the Japanese and US literature. We performed this study to quantify the rise in the prevalence of Moyamoya disease and to study the unique epidemiological and clinical features in the USA that may explain a change in incidence. METHODS: We analyzed data derived from patients entered in the Nationwide Inpatient Sample between 2005 and 2008, using ICD-9 codes for Moyamoya disease. Data including patient age, gender, ethnicity, secondary diagnosis, medical complications, and hospital costs were obtained. RESULTS: From 2005 to 2008 in the USA, there were an estimated 7,473 patients admitted with a primary or secondary diagnosis of Moyamoya disease. Patients admitted with Moyamoya disease were most frequently women and Caucasian. Overall, ischemic stroke was the most common reason for admission. Hemorrhagic stroke was more frequent in adults compared with children, 18.1 versus 1.5% (p < 0.05). CONCLUSION: The number of patients identified and admitted with Moyamoya disease has risen dramatically in the last decade. This study can lead to a better understanding of the disease pattern and healthcare consequences in the USA and suggests that pathophysiologic differences in Moyamoya disease may exist.

Prevalence and characteristics of concurrent down syndrome in patients with moyamoya disease.

BACKGROUND: An association between moyamoya disease and Down syndrome appears to exist on the basis of reported anecdotal cases in the literature. OBJECTIVE: To determine the prevalence of Down syndrome associated with moyamoya disease in inpatients and to identify the demographic and clinical features of moyamoya disease that may be unique when associated with Down syndrome. METHODS: In this observational study, we analyzed data from the Nationwide Inpatient Sample between 2002 and 2009 using International Classification of Diseases codes for moyamoya disease and Down syndrome for patient identification. Data including patient age, sex, race/ethnicity, secondary diagnosis, procedures, hospital costs, and patient outcomes were obtained. RESULTS: From 2002 to 2009, an estimated 518 patients (mean ± SD age, 16.2 ± 1.68 years) with coexisting moyamoya disease and Down syndrome were admitted. The estimated prevalence was 3.8% (3760 per 100,000) among patients admitted with moyamoya disease and 9.5% (9540 per 100,000) among moyamoya patients < 15 years of age. Patients admitted with moyamoya disease and Down syndrome were most frequently white and Hispanic (P = .02). They were more likely to present with ischemic stroke and less commonly with hemorrhagic stroke (15.3% and 2.7%, respectively; P < .05). CONCLUSION: This is the first study to estimate the prevalence of Down syndrome in patients with moyamoya disease. The 26-fold-greater prevalence of Down syndrome in patients with coexisting moyamoya disease compared with the prevalence of Down syndrome among live births (145 per 100,000) highlights the need for a better understanding of the common pathophysiology of the 2 conditions.

Physiologic changes during helium insufflation in high-risk patients during laparoscopic renal procedures.

OBJECTIVES: To assess the efficacy and safety of helium as an insufflant for transabdominal laparoscopic renal surgery. METHODS: The charts of all patients undergoing laparoscopic renal surgery with helium insufflation by a single physician between May 2003 and April 2006 were reviewed. Ventilatory parameters and postoperative recovery were reviewed. RESULTS: Ten patients underwent laparoscopic renal surgery with helium. These patients had a mean age of 64 years and suffered from a variety of comorbid conditions, including chronic obstructive pulmonary disease (5), congestive heart failure (1), chronic hypoxia from an intrapulmonary shunt (1), malignant hyperthermia (1), and chronic hypoxia from multiple pulmonary infarcts (1). All patients tolerated helium pneumoperitoneum, with mean O2 saturation of 98.6% +/- 0.6%, end-tidal CO2 31.4 +/- 1.7 mm Hg, respiratory rate 9.3 +/- 0.7 breaths per minute, tidal volumes 598.2 +/- 38.0 mL, and peak airway pressures 26.0 +/- 1.2 cm H2O. One patient developed an end-tidal CO2 of greater than 45 mm Hg. Mean operative time was 146.8 +/- 59 minutes, and estimated blood loss was 280.1 +/- 334 mL. Postoperatively 3 patients required continued maintenance of the endotracheal tube, although none required intubation longer than 22 hours. Five patients had critical care monitoring (1.7 +/- 2.9 days on average). CONCLUSIONS: Helium can be used safely as an insufflant during laparoscopic renal surgery. Patients who may benefit are those with potential difficulty in clearing CO2 gas from their bloodstream or those who rely on sensitive monitoring of end-tidal CO2 to manage comorbid pathology.