Bruce I Tranmer

University of Vermont, Burlington, VT, United States

Are you Bruce I Tranmer?

Claim your profile

Publications (43)125.88 Total impact

  • Anand I Rughani, Travis M Dumont, Bruce I Tranmer
    Journal of neurosurgery. Spine 01/2014; · 1.61 Impact Factor
  • T M Dumont, C T Lin, B I Tranmer, M A Horgan
    [Show abstract] [Hide abstract]
    ABSTRACT: INTRODUCTION: The UNIPLATE (DePuy Spine) was developed to improve operative time and limit dissection at the lateral margins of the vertebral bodies. The distinguishing character of this plate is its thin design requiring only one screw per vertebral level (monovertebral screw plate). Most cervical spine plates, in contrast, are designed for two screws per vertebral level (bivertebral screw plate). Limited reports of the biomechanical efficacy of the UNIPLATE are available, and to the authors' knowledge, this represents the largest clinical study of its use. METHODS: This is a retrospective chart-review study of consecutively treated patients without prior cervical spine surgery undergoing anterior cervical diskectomy and fusion at one or two levels. The primary endpoint is symptomatic pseudarthrosis requiring revision surgery. Pseudarthrosis is defined as a failure of bony fusion on the operated level seen on thin-cut CT scans performed on symptomatic patients. The rate of revision surgery due to symptomatic pseudarthrosis is compared between patients undergoing one and two level fusion surgeries patients treated with UNIPLATE compared to other plates with two screws per vertebral level. The minimum follow-up is 18 months. RESULTS: A total of 162 patients were identified, including 125 patients with one level fusion and 37 patients with two level fusion surgery. The median follow-up period was 3.3 years. A significantly higher incidence (odds ratio 10.2, p = 0.042) of re-operation for symptomatic pseudarthrosis was noted for patients treated with the UNIPLATE (4 of 13, 31%) compared to patients treated with bivertebral screw plates (1 of 24, 2.5%). No significant difference in re-operation due to symptomatic pseudarthrosis was noted for different plating systems for one-level fusion surgeries CONCLUSIONS: There is an increased rate of re-operation for symptomatic pseudarthrosis after anterior cervical diskectomy and fusion surgery with the use of a monovertebral screw semi-constrained plate, particularly in two-level fusion surgeries. Use of the UNIPLATE system has since been abandoned in favor of bivertebral screw plating systems.
    World Neurosurgery 03/2013; · 1.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: : In 2003 the Accreditation Council for Graduate Medical Education implemented duty-hour restrictions for residents, with an unclear impact on patient care. : The authors hypothesize that implementation of duty-hour restrictions is not associated with decreased morbidity for neurosurgical patients. This hypothesis was tested with the Nationwide Inpatient Sample to examine inpatient complications associated with a common elective procedure, craniotomy for meningioma. : The Nationwide Inpatient Sample was queried for all patients admitted for elective craniotomy for meningioma from 1998 to 2008, excluding the year 2003. Each case was queried for common in-hospital postoperative complications. The complication rate was compared for 5-year epochs at teaching and nonteaching hospitals before (1998-2002) and after (2004-2008) the adoption of the Accreditation Council for Graduate Medical Education work-hour restriction. Multivariate analysis was performed to control for the effects of age and medical comorbidities. : We identified 21 177 patients who met inclusion criteria. We identified an effect of age, preexisting medical comorbidity, and timing of surgery on postoperative complication rates. At teaching hospitals, the complication rate increased from 14% to 16% (P < .001). In contrast, this increase was not mirrored at nonteaching hospitals, which saw a nearly constant postoperative complication rate of 15% from 1998 to 2002 and 15% for the years 2004 to 2008 (P = .979). This effect remained significant in a multivariate analysis including age and existing comorbidities as covariates (P = .016). : In patients undergoing craniotomy for meningioma, postoperative complication rates increased at teaching hospitals, but not at nonteaching hospitals over the 5-year epochs before and after 2003. : ACGME, Accreditation Council for Graduate Medical EducationICD-9-CM, International Classification of Diseases, 9th RevisionNIS, Nationwide Inpatient Sample.
    Neurosurgery 08/2012; 71(5):1041-6. · 2.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: : Large intracranial hemorrhages often require surgical management. For large intracranial hemorrhages associated with INR elevation due to oral anticoagulation therapy (OAT), timely evacuation of the hemorrhage provides the best chance for meaningful recovery and rapid correction of their INR is essential prior to surgical management. An understanding of the pharmacokinetics of INR reversal with fresh frozen plasma (FFP) may hasten dosing and decrease delays to life-saving surgery. : This study retrospectively evaluated the corresponding drop in INR per dose of FFP in head injury patients whose INR was being corrected with FFP. Consecutively treated patients with head trauma between January 2007 and July 2010 with INR elevation were studied (149 patients). Individual cases were assessed for FFP doses and resultant INR, as well as relevant demographic data including age, weight, height, BMI and concomitant use of Vitamin K. The change of INR relative to each administered dose of FFP was calculated, and a resultant dose-response curve produced using linear regression analysis. : A linear relationship (delta INR = 0.0725(number FFP dosed) +0.927); R squared = 0.845) between INR change and FFP dose was extrapolated (FIGURE 1). No significant change in this relationship was evident when patient's age, volume of distribution, or vitamin K administration was taken into consideration. A dose response matrix to guide FFP administration to a normal value (less than 1.4) was generated as a quick reference. : Our retrospective analysis of FFP dosing for correction of INR in patients on OAT with intracranial hemorrhage suggests that there is a predictable dose response relationship to units of FFP administered and concomitant decrease in INR. A dose response matrix to guide FFP administration to a normal value (less than 1.4) was generated as a quick reference for clinical use (Table 1).
    Neurosurgery 08/2012; 71(2):E560-1. · 2.53 Impact Factor
  • Anand I Rughani, Bruce I Tranmer, Travis M Dumont
    World Neurosurgery 07/2012; · 1.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: To propose that chronic subdural hematoma (CSDH) should be conceived as a sentinel event in elderly patients and offer an analysis of long-term survival after diagnosis. METHODS: A retrospective review of 301 consecutive patients ≥55 years old admitted to an academic medical center with a primary diagnosis of CSDH between January 1996 and January 2010 was performed. The effects of advanced age and surgical intervention on survival were independently assessed. These groups were compared with standardized mortality ratios (SMRs) on the basis of patient age at time of presentation. RESULTS: Mortality after diagnosis of CSDH increases with increased age at presentation. For all patients, the median survival was roughly 4 years after diagnosis (4.0 years ± 0.5). Median survival is decreased with older age at presentation, to a nadir of 1.5 years ± 0.6 for patients ≥85 years old (P = 0.0003, log-rank test). Compared with the reference data from the U.S. Centers of Disease Control and Prevention, 1-year SMR was increased in all age groups. An asymmetric increase in SMR was seen between age groups, with the greatest effect on the youngest subpopulation (SMR 2.9). CONCLUSIONS: The increased mortality rates in patients with CSDHs relative to standardized mortality data corroborate the conception of subdural hematoma as a sentinel health event.
    World Neurosurgery 06/2012; · 1.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The Accreditation Council for Graduate Medical Education instituted mandatory 80-hour work-week limitations in July 2003. The work-hour restriction was met with skepticism among the academic neurosurgery community and is thought to represent a barrier to teaching, ultimately compromising patient care. The authors hypothesize that the introduction of the mandatory resident work-hour restriction corresponds with an overall increase in morbidity rate. This study compares the morbidity and mortality rates on an academic neurological surgery service before and after institution of the work-hour restriction. Complications are individually assessed at a monthly divisional conference by neurosurgical faculty and residents. A prospective database was commenced in July 2000 recording all complications, complications that were deemed to be potentially avoidable ("possibly preventable"), and complications that were deemed unavoidable. The incidence of morbidity and mortality from July 2000 to June 2003 is compared with the incidence from July 2003 to June 2006. The overall rate of morbidity and mortality increased from 103 to 114 per 1000 patients treated after institution of the work-hour restriction, although this increase was not statistically significant (χ(2)(1, N = 8546) = 2.6, p = 0.106). The morbidity rate increased from 70 to 89 per 1000 patients treated after institution of the work-hour restriction (χ(2)(1, N = 8546) = 10, p = 0.001). The overall mortality rate was diminished from 32 to 27 per 1000 patients treated after institution of the work-hour restriction (χ(2)(1, N = 8546) = 3.2, p = 0.075). Morbidities considered avoidable or possibly preventable were seen to increase from 56 to 66 per 1000 patients treated (χ(2)(1, N = 8546) = 5.7, p = 0.017). Avoidable or possibly preventable mortalities numbered 3 per 1000 patients treated, and this rate did not change after introduction of the work-hour restriction (χ(2)(1, N = 8546) = 0.08, p = 0.777). The morbidity rate on a neurological surgery service is increased after implementation of the work-hour restriction. Mortality rates remain unchanged.
    Journal of Neurosurgery 12/2011; 116(3):483-6. · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Microvascular decompression (MVD) offers an effective and durable treatment for patients suffering from trigeminal neuralgia (TN). Because the disorder has a tendency to occur in older persons, the risks of surgical treatment in the elderly have been a topic of recent interest. To date, evidence derived from several small retrospective and a single prospective case series has suggested that age does not increase the complication rate associated with surgery. Using a large national database, the authors aimed to study the impact of age on in-hospital complications following MVD for TN. Using the Nationwide Inpatient Sample (NIS) for the 10-year period from 1999 to 2008, the authors selected all patients who underwent MVD for TN. The primary outcome of interest was the in-hospital mortality rate. Secondary outcomes of interest were cardiac, pulmonary, thromboembolic, cerebrovascular, and wound complications as well as the duration of hospital stay, total hospital charges, and discharge location. An elderly cohort of patients was first defined as those 65 years of age and older and then redefined as those 75 years and older. A total of 3273 patients who underwent MVD for TN were identified, having a median age of 57 years. Within this sample, 31.5% were 65 years and older and 10.7% were 75 years and older. The in-hospital mortality rate was 0.68% for patients 65 years or older (p = 0.0087) and 1.16% for those 75 years or older (p = 0.0026). In patients younger than 65 years, the in-hospital mortality rate was 0.13% (3 deaths among 2241 patients). As analyzed using the chi-square test (for both 65 and 75 years as the age cutoff) and the Pearson rank correlation coefficient, the risk of cardiac, pulmonary, thromboembolic, and cerebrovascular complications was higher in older patients (that is, those 65 and older and those 75 and older), but the risks of wound complications and CNS infection were not. The risk of any in-hospital complication occurring in a patient 65 years and older was 7.36% (p < 0.0001) and 10.0% in those 75 years and older (p < 0.0001). There was no difference in the total hospital charges associated with age. The duration of the hospital stay was longer in older patients, and the likelihood of discharge home was lower in older patients. Microvascular decompression for TN in the elderly population remains a reasonable surgical option. However, based on data from a large national database, authors of the present study suggest that complications do tend to gradually increase in tandem with an advanced age. While age does not act as a risk factor in isolation, it may serve as a convenient surrogate for complication rates. The authors hope that this information can be of use in guiding older patients through decisions for the surgical treatment of TN.
    Journal of Neurosurgery 05/2011; 115(2):202-9. · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Helmet use has been associated with fewer hospital visits among injured skiers and snowboarders, but there remains no evidence that helmets alter the intracranial injury patterns. The authors hypothesized that helmet use among skiers and snowboarders reduces the incidence of head injury as defined by findings on head CT scans. The authors performed a retrospective review of head-injured skiers and snowboarders at 2 Level I trauma centers in New England over a 6-year period. The primary outcome of interest was intracranial injury evident on CT scans. Secondary outcomes included the following: need for a neurosurgical procedure, presence of spine injury, need for ICU admission, length of stay, discharge location, and death. Of the 57 children identified who sustained a head injury while skiing or snowboarding, 33.3% were wearing a helmet at the time of injury. Of the helmeted patients, 5.3% sustained a calvarial fracture compared with 36.8% of the unhelmeted patients (p = 0.009). Although there was a favorable trend, there was no significant difference in the incidence of epidural hematoma, subdural hematoma, intraparenchymal hemorrhage, subarachnoid hemorrhage, or contusion in helmeted and unhelmeted patients. With regard to secondary outcomes, there were no significant differences between the 2 groups in percentage of patients requiring neurosurgical intervention, percentage requiring admission to an ICU, total length of stay, or percentage discharged home. There was no difference in the incidence of cervical spine injury. There was 1 death in an unhelmeted patient, and there were no deaths among helmeted patients. Among hospitalized children who sustained a head injury while skiing or snowboarding, a significantly lower number of patients suffered a skull fracture if they were wearing helmets at the time of the injury.
    Journal of Neurosurgery Pediatrics 03/2011; 7(3):268-71. · 1.63 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Subarachnoid hemorrhage (SAH) following cerebral aneurysm rupture is associated with high rates of morbidity and mortality. Surviving SAH patients often suffer from neurological impairment, yet little is currently known regarding the influence of subarachnoid blood on brain parenchyma. The objective of the present study was to examine the impact of subarachnoid blood on glial cells using a rabbit SAH model. The astrocyte-specific proteins, glial fibrillary acidic protein (GFAP) and S100B, were up-regulated in brainstem from SAH model rabbits, consistent with the development of reactive astrogliosis. In addition to reactive astrogliosis, cytosolic expression of the pro-inflammatory cytokine, high-mobility group box 1 protein (HMGB1) was increased in brain from SAH animals. We found that greater than 90% of cells expressing cytosolic HMGB1 immunostained positively for Iba1, a specific marker for microglia and macrophages. Further, the number of Iba1-positive cells was similar in brain from control and SAH animals, suggesting the majority of these cells were likely resident microglial cells rather than infiltrating macrophages. These observations demonstrate SAH impacts brain parenchyma by activating astrocytes and microglia, triggering up-regulation of the pro-inflammatory cytokine HMGB1.
    Translational Stroke Research 03/2011; 2(1):72-79.
  • Travis M Dumont, Anand I Rughani, Bruce I Tranmer
    [Show abstract] [Hide abstract]
    ABSTRACT: To create a simple artificial neural network (ANN) to predict the occurrence of symptomatic cerebral vasospasm (SCV) after aneurysmal subarachnoid hemorrhage (aSAH) based on clinical and radiographic factors and test its predictive ability against existing multiple logistic regression (MLR) models. A retrospective database of patients admitted to a single academic medical center with confirmed aSAH between January 2002 and January 2007 (91 patients) was input to a back-propagation ANN program freely available to academicians on the Internet. The resulting ANN was prospectively tested against two previously published MLR prediction models for all patients admitted the following year (22 patients). The models were compared for their predictive accuracy with receiver operating characteristic (ROC) curve analysis. All models were accurate with their prediction of patients with SCV. The ANN had superior predictive value compared with the MLR models, with a significantly improved area under ROC curve (0.960 ± 0.044 vs 0.933 ± 0.54 and 0.897 ± 0.069 for MLR models). A simple ANN model was more sensitive and specific than MLR models in prediction of SCV in patients with aSAH. The conception of ANN modeling for cerebral vasospasm is introduced for a neurosurgical audience. With advanced ANN modeling, the clinician may expect to build improved models with more powerful prediction capabilities.
    World Neurosurgery 01/2011; 75(1):57-63; discussion 25-8. · 1.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Accurate assessment of imaging studies in patients with ventriculoperitoneal shunts can be aided by empirical findings. The authors characterize an objective measurement easily performed on head CT scans with the goal of producing clear evidence of shunt fracture or disconnection in patients with a snap shunt-type system. The authors describe 2 cases of ventriculoperitoneal shunt failure involving a fracture and a disconnection associated with a snap-shunt assembly. In both cases the initial clinical symptoms were not convincing for shunt malfunction, and the interpretation of the CT finding failed to immediately identify the abnormality. As the clinical picture became more convincing for shunt malfunction, each patient subsequently underwent successful shunt revision. The authors reviewed the CT scans of 10 patients with an intact and functioning snap-shunt system to characterize the normal appearance of the snap-shunt connection. On CT scans the distance between the radiopaque portion of the ventricular catheter and the radiopaque portion of the reservoir dome measures an average of 4.72 mm (range 4.6-4.9 mm, 95% CI 4.63-4.81 mm). In the authors' patient with a fractured ventricular catheter, this interval measured 7.8 mm, and in the patient with a disconnection it measured 7.7 mm. In comparison with the range of normal values, a radiolucent interval significantly greater than 4.9 mm should promptly raise concern for a disconnected or fractured shunt in this system. This measurement may prove particularly useful when serial imaging is not readily available.
    Journal of Neurosurgery Pediatrics 09/2010; 6(3):299-302. · 1.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Carcinoma of the anal canal is a relatively rare cancer with a low propensity for metastasis. A literature review identifies two cases of brain metastases from anal cancer. The authors present the case of a 63-year-old female with poorly differentiated squamous cell carcinoma of the anal canal who presented with a solitary dural-based enhancing lesion of the right parietal area. The patient underwent craniectomy and tumor resection. Histopathology confirmed the cerebral lesion to be a poorly differentiated squamous cell carcinoma, consistent with the known primary tumor of the anal canal. Although exceptionally rare, the presence of a cerebral lesion in a patient with carcinoma of the anal canal should raise the possibility of metastatic disease. Treatment decisions in patients with newly diagnosed dural-based enhancing lesions and known anal cancer should bear in mind the possibility of metastatic disease.
    Journal of Neuro-Oncology 05/2010; 101(1):141-3. · 3.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the setting of acute brainstem herniation in traumatic brain injury (TBI), the use of hyperventilation to reduce intracranial pressure may be life-saving. However, undue use of hyperventilation is thought to increase the incidence of secondary brain injury through direct reduction of cerebral blood flow. This is a retrospective review determining the effect of prehospital hyperventilation on in-hospital mortality following severe TBI. All trauma patients admitted directly to a single level 1 trauma center from January 2000 to January 2007 with an initial Glasgow Coma Scale (GCS) score <or=8 were included in the study (n = 77). Patients without documented or with late (>20 min) arterial blood gas at presentation (n = 12) were excluded from the study. The remaining population (n = 65) was sorted into three groups based on the initial partial pressure of carbon dioxide: hypocarbic (Pco(2) < 35 mm Hg), normocarbic (Pco(2) 35-45 mm Hg), and hypercarbic (Pco(2) > 45 mm Hg). Outcome was based on mortality during hospital admission. Survival was found to be related to admission Pco(2) in head trauma patients requiring intubation (p = 0.045). Patients with normocarbia on presenting arterial blood gas testing had in-hospital mortality of 15%, significantly improved over patients presenting with hypocarbia (in-hospital mortality 77%) or hypercarbia (in-hospital mortality 61%). Although there are many reports of the negative impact of prophylactic hyperventilation following severe TBI, this modality is frequently utilized in the prehospital setting. Our results suggest that abnormal Pco(2) on presentation after severe head trauma is correlated with increased in-hospital mortality. We advocate normoventilation in the prehospital setting.
    Journal of neurotrauma 04/2010; 27(7):1233-41. · 4.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Raymond M. P. Donaghy was one of the true pioneers of modern neurosurgery. His restless dedication, innovation, and desire to humbly disseminate his knowledge facilitated the advancement of the field of microneurosurgery. Many of his trainees--most notably M. Gazi Yaşargil--continued to advance the field, developing innovative microsurgical instruments and techniques. The history of microneurosurgery is incomplete without a glimpse at the life of this remarkable man.
    Journal of Neurosurgery 01/2010; 112(6):1176-1181. · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The authors describe the artificial neural network (ANN) as an innovative and powerful modeling tool that can be increasingly applied to develop predictive models in neurosurgery. They aimed to demonstrate the utility of an ANN in predicting survival following traumatic brain injury and compare its predictive ability with that of regression models and clinicians. The authors designed an ANN to predict in-hospital survival following traumatic brain injury. The model was generated with 11 clinical inputs and a single output. Using a subset of the National Trauma Database, the authors "trained" the model to predict outcome by providing the model with patients for whom 11 clinical inputs were paired with known outcomes, which allowed the ANN to "learn" the relevant relationships that predict outcome. The model was tested against actual outcomes in a novel subset of 100 patients derived from the same database. For comparison with traditional forms of modeling, 2 regression models were developed using the same training set and were evaluated on the same testing set. Lastly, the authors used the same 100-patient testing set to evaluate 5 neurosurgery residents and 4 neurosurgery staff physicians on their ability to predict survival on the basis of the same 11 data points that were provided to the ANN. The ANN was compared with the clinicians and the regression models in terms of accuracy, sensitivity, specificity, and discrimination. Compared with regression models, the ANN was more accurate (p < 0.001), more sensitive (p < 0.001), as specific (p = 0.260), and more discriminating (p < 0.001). There was no difference between the neurosurgery residents and staff physicians, and all clinicians were pooled to compare with the 5 best neural networks. The ANNs were more accurate (p < 0.0001), more sensitive (p < 0.0001), as specific (p = 0.743), and more discriminating (p < 0.0001) than the clinicians. When given the same limited clinical information, the ANN significantly outperformed regression models and clinicians on multiple performance measures. While this paradigm certainly does not adequately reflect a real clinical scenario, this form of modeling could ultimately serve as a useful clinical decision support tool. As the model evolves to include more complex clinical variables, the performance gap over clinicians and logistic regression models will persist or, ideally, further increase.
    Journal of Neurosurgery 12/2009; 113(3):585-90. · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The Subdural Evacuating Port System (SEPS) was recently introduced as a novel method of treating chronic subdural hematomas (SDHs). This system is a variation of the existing twist-drill craniostomy methods for treating chronic SDH. Compared with craniotomy or bur hole treatment of chronic SDH, this system offers the possibility of treatment at bedside without general anesthesia. In comparison with existing twist-drill methods, the system theoretically offers the advantage of a hermetically closed system that can evacuate a hematoma without an intracranial catheter. The authors performed a case-control study of all chronic SDHs treated at a single institution over a 5-year period and compared the efficacy and safety of the SEPS to bur hole evacuation. Patients were matched for age, injury mechanism, medical comorbidities, use of anticoagulation, and radiographic appearance of the SDH. The primary outcome of interest was the recurrence rate in each group, which was evaluated by radiographic evidence as well as the number of patients requiring a second procedure. Secondary outcomes examined were mortality, infection, acute hematoma formation, seizure, length of hospital stay, length of intensive care unit stay, and discharge location. The authors found that there were no appreciable differences in symptoms on presentation, existing comorbidities, home medications, or laboratory values between the treatment groups. The average Hounsfield units of preoperative CT scanning was similar in both groups. Radiographic recurrence was statistically similar between the SEPS group (25.9%) and the bur hole group (18.5%; p = 0.37). Although there was a trend toward higher reoperation rates in the SEPS group, the need for a subsequent procedure was also statistically similar between the SEPS group (25.9%) and the bur hole group (14.8%; p = 0.25). The mortality rate was not significantly different between the SEPS group (9.5%) and the bur hole group (4.8%; p = 0.50). The SEPS procedure provided a mean reduction in SDH thickness of 27.3% compared with 37.9% with bur hole (p = 0.05) when comparing the preoperative CT scan with the first postoperative CT scan. The percentage of reduction in SDH thickness when comparing the preoperative CT scan with the most recent postoperative CT scan was 40.5% in the SEPS group and 45.4% in the bur hole group (p = 0.31). The SEPS offers an alternative type of twist-drill craniostomy for the treatment of chronic SDH with a trend toward higher recurrence in our experience. The efficacy and safety of SEPS is similar to that of other twist-drill methods reported in the literature. In the authors' experience, the efficacy of this treatment as measured by radiographic worsening or the need for a subsequent procedure is statistically similar to that of bur hole treatment. There was no difference in mortality or other adverse outcomes associated with SEPS.
    Journal of Neurosurgery 12/2009; 113(3):609-14. · 3.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Symptomatic cerebral vasospasm (SCV) is a morbid sequela of subarachnoid hemorrhage (SAH). Its etiology is multifactorial and predicting onset can be challenging. Diabetes mellitus (DM) is known to affect vasoactive properties of vessels, but it has not been definitively correlated with SCV. We report that pre-existing DM is independently and strongly correlated with SCV, despite intensive glycemic control. This is a retrospective chart review of all patients with aneurysmal subarachnoid hemorrhage (aSAH) admitted to a single academic medical center between January 2002 and January 2008 (n = 145). Patients presenting greater than 14 days after ictus, as well as those not surviving the first 3 days post-ictus were excluded from analysis. Remaining patients (n = 113) were assessed for study parameters including pre-existing DM, mean daily blood glucose, and additional known correlates to SCV. Multivariate analysis was performed to assess risk factors for SCV development. The primary outcome measure was SCV, defined as neurological change in conjunction with evidence of vessel spasm by either angiography or transcranial ultrasound. Of 113 patients included in the study, 42 (37%) had SCV. Patients with DM (80% incidence of SCV) had an increased risk of subsequently developing SCV (OR 9.90, P = 0.031). Elevated blood glucose was not associated with increased risk of vasospasm and no difference in glycemic control was noted between patients with or without DM. SCV resulted in worsened mortality and Glasgow Outcome Score for survivors (P < 0.005). In this group of patients with SAH, diabetes mellitus is identified as a risk factor for development of SCV. Blood glucose management during hospitalization was similar in diabetics and non-diabetics, suggesting that the longstanding effects of microvascular disease may be more relevant in the development of SCV then acute glycemic control in these patients.
    Neurocritical Care 06/2009; 11(2):183-9. · 3.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The author report a case of a 74-year-old man who had presented with transient bilateral brachial diplegia. Investigations led to the diagnosis and treatment of subclavian artery stenosis. There are no known published cases of subclavian artery stenosis associated with transient bilateral arm weakness, and the authors believe that a steal phenomenon leading to vertebrobasilar artery insufficiency and subsequent anterior spinal artery insufficiency may have caused these symptoms, which resolved after correction of the patient's stenosis.
    Journal of Neurosurgery Spine 09/2008; 9(2):191-5. · 1.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cerebral vasospasm after subarachnoid hemorrhage (SAH) is a major contributor to mortality and morbidity after aneurysm rupture. Recently, R-type voltage-dependent Ca(2+) channel (VDCC) expression has been associated with increased cerebral artery constriction in a rabbit model of SAH. The goal of the present study was to examine whether the blood component oxyhemoglobin (oxyHb) can mimic the ability of SAH to cause R-type VDCC expression in the cerebral vasculature. Rabbit cerebral arteries were organ cultured in serum-free media for up to 5 days in the presence or absence of purified oxyHb (10 micromol/L). Diameter changes in response to diltiazem, (L-type VDCC antagonist) and SNX-482 (R-type VDCC antagonist) were recorded at day 1, 3, or 5 in arteries constricted by elevated extracellular potassium. RT-PCR was performed on RNA extracted from arteries cultured for 5 days (+/-oxyHb) to assess VDCC expression. After 5 days, oxyHb-treated arteries were less sensitive and partially resistant to diltiazem compared to similar arteries organ cultured in the absence of oxyHb. Further, SNX-482 dilated arteries organ cultured for 5 days in the presence, but not in the absence, of oxyHb. RT-PCR revealed that oxyHb treated arteries expressed R-type VDCCs (Ca(V) 2.3) in addition to L-type VDCCs (Ca(V) 1.2), whereas untreated arteries expressed only Ca(V) 1.2. These results demonstrate that oxyhemoglobin exposure for 5 days induces the expression of Ca(V) 2.3 in cerebral arteries. We propose that oxyhemoglobin contributes to enhanced cerebral artery constriction after SAH via the emergence of R-type VDCCs.
    Stroke 08/2008; 39(7):2122-8. · 6.16 Impact Factor

Publication Stats

374 Citations
125.88 Total Impact Points


  • 2004–2012
    • University of Vermont
      • • Division of Neurosurgery
      • • Department of Pharmacology
      Burlington, VT, United States
  • 2008
    • Champlain College
      • Division of Information Technology and Sciences
      Burlington, Vermont, United States