Person: Walcott, Brian
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Publication Interfacility Helicopter Ambulance Transport of Neurosurgical Patients: Observations, Utilization, and Outcomes from a Quaternary Level Care Hospital
(Public Library of Science (PLoS), 2011) Walcott, Brian; Coumans, Jean-Valery; Mian, Matthew; Nahed, Brian; Kahle, Kristopher T.Background: The clinical benefit of helicopter transport over ground transportation for interfacility transport is unproven. We sought to determine actual practice patterns, utilization, and outcomes of patients undergoing interfacility transport for neurosurgical conditions. Methodology/Principal Findings: We retrospectively examined all interfacility helicopter transfers to a single trauma center during 2008. We restricted our analysis to those transfers leading either to admission to the neurosurgical service or to formal consultation upon arrival. Major exclusion criteria included transport from the scene, death during transport, and transport to any area of the hospital other than the emergency department. The primary outcome was time interval to invasive intervention. Secondary outcomes were estimated ground transportation times from the referring hospital, admitting disposition, and discharge disposition. Of 526 candidate interfacility helicopter transfers to our emergency department in 2008, we identified 167 meeting study criteria. Seventy-five (45%) of these patients underwent neurosurgical intervention. The median time to neurosurgical intervention ranged from 1.0 to 117.8 hours, varying depending on the diagnosis. For 101 (60%) of the patients, estimated driving time from the referring institution was less than one hour. Four patients (2%) expired in the emergency department, and 34 patients (20%) were admitted to a non-ICU setting. Six patients were discharged home within 24 hours. For those admitted, in-hospital mortality was 28%. Conclusions/Significance: Many patients undergoing interfacility transfer for neurosurgical evaluation are inappropriately triaged to helicopter transport, as evidenced by actual times to intervention at the accepting institution and estimated ground transportation times from the referring institution. In a time when there is growing interest in health care cost containment, practitioners must exercise discretion in the selection of patients for air ambulance transport—particularly when it may not bear influence on clinical outcome. Neurosurgical evaluation via telemedicine may be one strategy for improving air transport triage.
Publication Glioblastoma Mimicking an Arteriovenous Malformation
(Frontiers Media S.A., 2013) Khanna, Arjun; Venteicher, Andrew S; Walcott, Brian; Kahle, Kristopher T.; Mordes, Daniel; William, Christopher M.; Ghogawala, Zoher; Ogilvy, ChristopherAbnormal cerebral vasculature can be a manifestation of a vascular malformation or a neoplastic process. We report the case of a patient with angiography-negative subarachnoid hemorrhage (SAH) who re-presented 3 years later with a large intraparenchymal hemorrhage. Although imaging following the intraparenchymal hemorrhage was suggestive of arteriovenous malformation, the patient was ultimately found to have an extensive glioblastoma associated with abnormal tumor vasculature. The case emphasizes the need for magnetic resonance imaging to investigate angiography-negative SAH in suspicious cases to rule out occult etiologies, such as neoplasm. We also discuss diagnostic pitfalls when brain tumors are associated with hemorrhage and abnormal vasculature.
Publication Limitations of Current GABA Agonists in Neonatal Seizures: Toward GABA Modulation Via the Targeting of Neuronal Cl− Transport
(Frontiers Media S.A., 2013) Khanna, Arjun; Walcott, Brian; Kahle, Kristopher T.Neonatal intensive care has advanced rapidly in the last 40 years, with dramatic decreases in mortality and morbidity; however, for neonatal seizures, neither therapies nor outcomes have changed significantly. Basic and clinical studies indicate that seizures in neonates have long-term neurodevelopmental and psychiatric consequences, highlighting the need for novel pharmacotherapeutics. First-line treatments targeting GABAA receptors, like barbiturates and benzodiazepines, are limited in their efficacy and carry significant risks to the developing brain. Here, we review the use of current GABA agonist therapies for neonatal seizures and suggest other treatment strategies given recent developments in the understanding of disease pathogenesis. One promising avenue is the indirect manipulation of the GABAergic system, via the modulation of neuronal Cl− gradients, by targeting the cation-Cl− cotransporters (NKCC1 and KCC2) or their regulatory signaling molecules. This strategy might yield a novel class of more efficacious anti-epileptics with fewer side effects by specifically addressing disease pathophysiology. Moreover, this strategy may have ramifications for other adult seizure syndromes in which GABA receptor-mediated depolarizations play a pathogenic role, such as temporal lobe epilepsy.
Publication Volumetric analysis of syringomyelia following hindbrain decompression for Chiari malformation Type I: syringomyelia resolution follows exponential kinetics
(Journal of Neurosurgery Publishing Group (JNSPG), 2011) Coumans, Jean-Valery; Walcott, Brian; Butler, William; Nahed, Brian; Kahle, Kristopher T.Object: Resolution of syringomyelia is common following hindbrain decompression for Chiari malformation, yet little is known about the kinetics governing this process. The authors sought to establish the volumetric rate of syringomyelia resolution. Methods: A retrospective cohort of patients undergoing hindbrain decompression for a Chiari malformation Type I with preoperative cervical or thoracic syringomyelia was identified. Patients were included in the study if they had at least 3 neuroimaging studies that detailed the entirety of their preoperative syringomyelia over a minimum of 6 months postoperatively. The authors reconstructed the MR images in 3 dimensions and calculated the volume of the syringomyelia. They plotted the syringomyelia volume over time and constructed regression models using the method of least squares. The Akaike information criterion and Bayesian information criterion were used to calculate the relative goodness of fit. The coefficients of determination R2 (unadjusted and adjusted) were calculated to describe the proportion of variability in each individual data set accounted for by the statistical model. Results: Two patients were identified as meeting inclusion criteria. Plots of the least-squares best fit were identified as 4.01459e−0.0180804x and 13.2556e−0.00615859x. Decay of the syringomyelia followed an exponential model in both patients (R2 = 0.989582 and 0.948864). Conclusions: Three-dimensional analysis of syringomyelia resolution over time enables the kinetics to be estimated. This technique is yet to be validated in a large cohort. Because syringomyelia is the final common pathway for a number of different pathological processes, it is possible that this exponential only applies to syringomyelia related to treatment of Chiari malformation Type I.
Publication Deep brain stimulation for medically refractory life-threatening status dystonicus in children
(Journal of Neurosurgery Publishing Group (JNSPG), 2012) Walcott, Brian; Nahed, Brian; Kahle, Kristopher T.; Duhaime, Ann-Christine; Sharma, Nutan; Eskandar, EmadGeneralized dystonic syndromes may escalate into persistent episodes of generalized dystonia known as status dystonicus that can be life-threatening due to dystonia-induced rhabdomyolysis and/or respiratory compromise. Treatment of these conditions usually entails parenteral infusion of antispasmodic agents and sedatives and occasionally necessitates a medically induced coma for symptom control. The authors report a series of 3 children who presented with medically intractable, life-threatening status dystonicus and were successfully treated with bilateral pallidal deep brain stimulation. Bilateral globus pallidus internus stimulation appears to be effective in the urgent treatment of medically refractory and life-threatening movement disorders.
Publication Trends in peptic ulcer disease and the identification of Helicobacter Pylori as a causative organism: Population-based estimates from the US nationwide inpatient sample
(Medknow, 2011) Walcott, Brian; Bashinskaya, Bronislava; Nahed, Brian; Redjal, Navid; Kahle, Kristopher T.Background: Peptic ulcer disease can lead to serious complications including massive hemorrhage or bowel perforation. The modern treatment of peptic ulcer disease has transitioned from the control of gastric acid secretion to include antibiotic therapy in light of the identification of Helicobacter pylori as a causative infectious organism. We sought to determine trends related to this discovery by using a national database. Materials and Methods: Patient discharges with peptic ulcer disease and associated sequelae were queried from the Nationwide Inpatient Sample, 1993 to 2007, under the auspices of a data user agreement. To account for the Nationwide Inpatient Sample weighting schema, design-adjusted analyses were used. Standard error was calculated using SUDAAN software (Research Triangle International, NC, USA). Results: Decreases in the incidences of gastrointestinal perforation, gastrointestinal hemorrhage, and surgical procedures most specific to peptic ulcer disease were statistically significant over the study period [range of P value (two tailed) = 0.000 – 0.00353; significant at P < 0.001 to < 0.01]. The incidence of H. pylori rose dramatically, peaking at an estimated 97,823 cases in 1998 [SE = 3155; 95% CI = 6,184]. Since that time it has decreased and then stabilized. Conclusions:The identification of H. pylori as the causative agent in the majority of peptic ulcer disease has revolutionized the understanding and management of the disease. Medical conditions and surgical procedures associated with end-stage peptic ulcer disease have significantly decreased according to analysis of selected index categories. Resident physician education objectives may need to be modified in light of these trends. Review Criteria: We reviewed patients with peptic ulcer disease. The database used was the Nationwide Inpatient Sample, 1993 to 2007. Message for the Clinic: Medical therapy has resulted in decreased morbidity from H. pylori infection as it is the causative agent in the majority of peptic ulcer disease. Aggressive screening and treatment of this infection will lead to further reduction in morbidity.
Publication Trends in inpatient setting laminectomy for excision of herniated intervertebral disc: Population-based estimates from the US nationwide inpatient sample
(Medknow, 2011) Walcott, Brian; Hanak, Brian W; Caracci, James R; Redjal, Navid; Nahed, Brian; Kahle, Kristopher T.; Coumans, Jean-ValeryBackground: Herniated intervertebral discs can result in pain and neurological compromise. Treatment for this condition is categorized as surgical or non-surgical. We sought to identify trends in inpatient surgical management of herniated intervertebral discs using a national database. Methods: Patient discharges identified with a principal procedure relating to laminectomy for excision of herniated intervertebral disc were selected from the Nationwide Inpatient Sample (Healthcare Cost and Utilization Project - Agency for Healthcare Research and Quality, Rockville, MD), under the auspices of a data user agreement. These surgical patients did not undergo instrumented fusion. To account for the Nationwide Inpatient Sample weighting schema, design-adjusted analyses were used. The estimates of standard errors were calculated using SUDAAN software (Research Triangle International, NC, USA). This software is based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM); a uniform and standardized coding system. Results: Using International Classification of Disease 9th Revision clinical modifier (ICD-9 CM) procedure code 80.51, we were able to identify disc excision, in part or whole, by laminotomy or hemilaminectomy. The incidence of laminectomy for the excision of herniated intervertebral disc has decreased dramatically from 1993 where 266,152 cases were reported [CI = 22,342]. In 2007, only 123,398 cases were identified [CI = 12,438]. The average length of stay in 1993 was 4 days [CI = 0.17], and in 2007 it decreased to just 2 days [CI = 0.17]. Both these comparisons were significantly different at P < 0.001. The average inflation adjusted (2007 buying power) charge of the procedure in 1993 was 14,790.87 USD [CI = 916.85]. This value rose in 2007 to 24,639 USD [CI = 1,485.51]. This difference was significant at P < 0.001.Conclusions: National estimates indicate that the incidence of inpatient laminectomy for the excision of herniated intervertebral disc has decreased significantly. This trend is multifactorial and is likely related to developments in outcomes research, the growing popularity of alternative procedures (intervertebral instrumented fusion), and transition to an ambulatory setting of surgical care.
Publication Cerebral edema and a transtentorial brain herniation syndrome associated with pandemic swine influenza A (H1N1) virus infection
(Elsevier BV, 2011) Kahle, Kristopher T.; Walcott, Brian; Nahed, Brian; Barnard, Zachary R.; Lo, Eng; Buonanno, Ferdinando; Venna, Nagagopal; Ning, MingMingAcute encephalitis, encephalopathy, and seizures are known rare neurologic sequelae of respiratory tract infection with seasonal influenza A and B virus, but the neurological complications of the pandemic 2009 swine influenza A (H1N1) virus, particularly in adults, are ill-defined. We document two young adults suffering from H1N1-associated acute respiratory distress syndrome and renal failure who developed cerebral edema. The patients acutely developed a transtentorial brain herniation syndrome including a unilateral third nerve palsy (dilated and unresponsive pupils), elevated intracranial pressure, coma, and radiological evidence of diffuse cerebral edema. In both patients, neurological deterioration occurred in the context of hyponatremia and a systemic inflammatory state. These patients illustrate that severe neurologic complications, including malignant cerebral edema, can occur in adults infected with H1N1 virus, and illustrate the need for close neurological monitoring of potential neurological morbidities in future pandemics.
Publication Craniectomy for Malignant Cerebral Infarction: Prevalence and Outcomes in US Hospitals
(Public Library of Science (PLoS), 2011) Walcott, Brian; Kuklina, Elena V.; Nahed, Brian; George, Mary G.; Kahle, Kristopher T.; Simard, J. Marc; Asaad, Wael F.; Coumans, Jean-ValeryObject: Randomized trials have demonstrated the efficacy of craniectomy for the treatment of malignant cerebral edema following ischemic stroke. We sought to determine the prevalence and outcomes related to this by using a national database. Methods: Patient discharges with ischemic stroke as the primary diagnosis undergoing craniectomy were queried from the US Nationwide Inpatient Sample from 1999 to 2008. A subpopulation of patients was identified that underwent thrombolysis. Two primary end points were examined: in-hospital mortality and discharge to home/routine care. To facilitate interpretations, adjusted prevalence was calculated from the overall prevalence and two age-specific logistic regression models. The predictive margin was then generated using a multivariate logistic regression model to estimate the probability of in-hospital mortality after adjustment for admission type, admission source, length of stay, total hospital charges, chronic comorbidities, and medical complications. Results: After excluding 71,996 patients with the diagnosis of intracranial hemorrhage and posterior intracranial circulation occlusion, we identified 4,248,955 adult hospitalizations with ischemic stroke as a primary diagnosis. The estimated rates of hospitalizations in craniectomy per 10,000 hospitalizations with ischemic stroke increased from 3.9 in 1999–2000 to 14.46 in 2007–2008 (p for linear trend,0.001). Patients 60+ years of age had in-hospital mortality of 44% while the 18–59 year old group was found to be 24%(p = 0.14). Outcomes were comparable if recombinant tissue plasminogen activator had been administered. Conclusions: Craniectomy is being increasingly performed for malignant cerebral edema following large territory cerebral ischemia. We suspect that the increase in the annual incidence of DC for malignant cerebral edema is directly related to the expanding collection of evidence in randomized trials that the operation is efficacious when performed in the correct patient population. In hospital mortality is high for all patients undergoing this procedure.