bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the local anesthetic agent bupivacaine prior to application of the skull-pin holder for craniotomies
Authors: Mathieu David , Beaudry Mathieu , Martin René , McLelland Hans , Robert Bruno , Kenny Brendan 
Published: May 2009

Object. The authors conducted a double-blind prospective randomized study to determine whether infiltration of Mayfield skull-pin sites with 0.5% bupivacaine, compared with placebo, would prevent hemodynamic stimulation, thus allowing for a reduction in the quantity of anesthetic agents required.
Methods. Thirty patients were randomized into two groups. There was a significant increase in blood pressure (mean systolic blood pressure 10 mm Hg, p = 0.003) in patients in the placebo group compared with that in patients in the bupivacaine group 1 minute after securing the head holder.
Conclusions. The local administration of bupivacaine for anesthetic purposes before skull-pin application may prevent potentially hazardous hemodynamic stimulation.
Clinical application of a physically and chemically processed human substitute for dura mater
Authors: Dufrane Denis , Marchal Christophe , Cornu Olivier , Raftopoulos Christian , Delloye Christian 
Published: May 2009

Object. Allogenic human fascia lata used in neurosurgery as a dura mater substitute can be associated with the risk of virus and bacterium transmission and with a delay in its incorporation due to immunological and inflammatory reactions. The authors review their preliminary experience with a chemically and physically processed fascia lata graft.
Methods. Grafts that had been treated with solvent detergents, freeze-dried for conservation, and gamma irradiated (25,000 Gy) for sterilization were placed into 17 patients during neurosurgical procedures performed to treat brain tumors, cerebral malformations, trigeminal neuralgia, and posttraumatic lesions. The handling properties of the material, surgical wound features, and hematological parameters were evaluated. The average follow-up period was 23.8 ± 2.2 months (mean ± standard deviation). The handling properties and biocompatibility of these human dural substitutes were highly satisfactory and no major complications were observed. Postoperative computerized tomography or magnetic resonance images obtained in 13 patients revealed no abnormal findings at the site of fascia lata implantation. In one patient who underwent a second surgery performed 12 months after the initial operation, this dural substitute was found to have been recolonized by host fibroblastic cells and replaced by autologous collagenous tissue.
Conclusions. Human fascia lata that has been rendered safe by applying physical and chemical treatment is a fully biocompatible alternative to the dural graft materials currently available.
The efficacy and safety of aprotinin for hemostasis during intracranial surgery
Authors: Palmer James D. , Francis John L. , Pickard John D. , Iannotti Fausto 
Published: May 2009

Object. The aim of this study was to determine the safety and efficacy of prophylactic high-dose intravenous aprotinin in reducing intraoperative blood loss in the neurosurgical population.
Methods. A randomized, double-blind, placebo-controlled trial was conducted in parallel groups in two regional neurosurgical departments. One hundred patients with a preoperative diagnosis of intracranial meningioma or vestibular schwannoma subsequently confirmed on histological studies were included. All patients were older than 18 years of age, pregnancy had been excluded, there was no history of bleeding diathesis, no previous exposure to aprotinin, and no ingestion of antiplatelet or anticoagulant medications within the 2 weeks preceding surgery. Aprotinin was administered in doses of 30,000 kallikrein-inhibiting units (KIU)/kg body weight on induction of anesthesia and was continued as an infusion of 10,000 KIU/kg/hr until surgery was complete, or for a maximum of 8 hours. Intraoperative blood loss, blood transfusion, the Glasgow Outcome Scale score, and the Index of Independence were measured, and screening for deep vein thrombosis and the Mini-Mental State Examination were performed.
Conclusions. Intraoperative blood loss was reduced from 1014 ml (geometric mean) to 508 ml (p = 0.028). Although this study was not designed to evaluate the need for blood transfusion, 37 U of blood was used in 11 patients in the aprotinin group and 58 U in 13 patients in the placebo group (not significant). There were no significant differences in postoperative thrombotic risk or other outcome measures between treatment groups. Aprotinin therefore can be safely used to reduce intraoperative blood loss in patients who are not receiving anticoagulation therapy.
Hemorrhagic complication of stereotactic surgery in patients with movement disorders
Authors: Terao Tohru , Takahashi Hiroshi , Yokochi Fusako , Taniguchi Makoto , Okiyama Ryouichi , Hamada Ikuma 
Published: May 2009

Object. Small, asymptomatic hemorrhages are easier to detect during stereotactic surgery when magnetic resonance (MR) imaging is used for targeting rather than when traditional approaches, such as ventriculography, are performed with contrast material. In the present study the authors examined the actual incidence of intraoperative hemorrhages in patients with movement disorders who had undergone MR imaging—targeted surgery, microelectrode recording (MER)-guided implantation of deep brain stimulation (DBS) electrodes, or radiofrequency-induced coagulation surgery performed.
Methods. Ninety-six consecutive patients underwent a total of 116 stereotactic operations for movement disorders (57 operations for radiofrequency-induced coagulation and 59 for DBS electrode implantation) between January 1998 and November 2002. The authors investigated the correlation between hemorrhages and other factors including the location of the hemorrhage and the type of surgery performed.
Postoperative computerized tomography scans demonstrated the occurrence of intraoperative hemorrhages at 12 locations during 11 procedures (9.5% of all procedures). Nine hemorrhages occurred during 57 coagulation operations (15.8%). Within this group, the frequency of hemorrhages was highest during thalamotomy (five [21.7%] of 23 procedures) and lower during pallidotomy (four [11.8%] of 34 procedures). In contrast, only two intraventricular hemorrhages developed during 59 operations in which DBS electrodes were implanted (3.4%). In no case was hemorrhage detected in the main DBS target, that is, the subthalamic nucleus.
Conclusions. When small, asymptomatic hemorrhages were included in the estimation, the actual rate of hemorrhage was higher than that previously reported. Judging from the incidence of hemorrhage during coagulation and DBS surgeries, the authors suggest that the heat induced by coagulation may play a larger role than microelectrode penetration in the development of hemorrhage.
Attenuation of nitric oxide synthase isoform expression by mild hypothermia after focal cerebral ischemia: variations depending on timing of cooling
Authors: Karabiyikoglu Murat , Han Hyung Soo , Yenari Midori A. , Steinberg Gary K. 
Published: May 2009

Object. In this study the authors examined the influence of mild hypothermia on early expression of nitric oxide synthase (NOS) isoforms and peroxynitrite generation after experimental stroke.
Methods. In 82 male Sprague—Dawley rats, middle cerebral artery occlusion was performed for 2 hours by using the intraluminal suture model. The rats were maintained at their normal body temperature or exposed to 2 hours of intraischemic or postischemic (2-hour delay) mild hypothermia. Brains were collected 2, 6, and 24 hours after onset of ischemia for immunohistochemical and Western blot analysis of neuronal (n)NOS and inducible (i)NOS expression and peroxynitrite generation.
Conclusions. Western blots showed significantly increased nNOS and iNOS expression in the ischemic cortex at 2, 6, and 24 hours compared with sham-operated animals. The NOS expression was highest at 24 hours. Postischemic hypothermia attenuated nNOS expression at 6 and 24 hours to a greater extent than intraischemic hypothermia. Intraischemic hypothermia reduced iNOS expression at both 2 and 24 hours, whereas postischemic hypothermia decreased iNOS expression at 24 hours. Results of immunohistochemical studies showed that nNOS colocalized with the neuronal marker MAP-2 at all time points, whereas iNOS was initially localized to vessels, and then localized to activated microglia by 24 hours. Intraischemic but not postischemic hypothermia decreased the number of nitrotyrosine-positive cells in the ischemic cortex at 24 hours. Mild hypothermia significantly but differentially attenuates increases in NOS isoforms, with more robust nNOS suppression when cooling is delayed. This may have important implications for understanding the mechanism of hypothermic neuroprotection and for stroke therapy.
Validation of a near-infrared probe for detection of thin intracranial white matter structures
Authors: Giller Cole A. , Liu Hanli , Gurnani Prem , Victor Sundar , Yazdani Umar , German Dwight C. 
Published: May 2009

Object. The authors have developed an intracranial near-infrared (NIR) probe that analyzes the scattering of light emitted from its tip to measure the optical properties of cerebral tissue. Despite its success in distinguishing gray matter from white matter in humans during stereotactic surgery, the limits of this instrument's resolution remain unclear. In this study, the authors determined the spatial resolution of this new probe by using a rodent model supplemented with phantom measurements and computer simulation.
Methods. A phantom consisting of Intralipid and gelatin was constructed to resemble a layer of white matter overlying a layer of gray matter. Near-infrared measurements were obtained as the probe was inserted through the gray—white matter transition. A computer simulation of NIR measurements through a gray—white matter transition was also performed using Monte Carlo techniques. The NIR probe was then used to study 19 tracks from the cortical surface through the corpus callosum in an in vivo rodent preparation. The animals were killed and histological sections through the tracks were obtained.
Data from the phantom models and computer simulations showed that the NIR probe samples a volume of tissue extending 1 to 1.5 mm in front of the probe tip (this distance is termed the “lookthrough” distance). Measurements obtained from an NIR probe passing through a thin layer of white matter consisted of an initial segment of increasing values, a maximum (peak) value, and a trailing segment of decreasing values. The length of the initial segment is the lookthrough distance, the position of the peak indicates the location of the superficial white matter boundary, and the length of the trailing segment is the thickness of the layer.
These considerations were confirmed in experiments with rodents. All tracks passed through the corpus callosum, which was demonstrated as a broad peak on each NIR graph. The position of the dorsal boundary of the corpus callosum and its width (based on histological measurements) correlated well with the peak of the NIR curve and its trailing segment, respectively. The initial segments correlated well with estimates of the lookthrough distance. Five of the tracks transected the smaller anterior commissure (diameter 0.2 mm), producing a narrow NIR peak at the correct depth.
Conclusions. Data in this study confirm that the NIR probe can reliably detect and measure the thickness of layers of white matter as thin as 0.2 mm. Such resolution should be adequate to detect larger structures of interest encountered during stereotactic surgery in humans.
Primary hypertension—induced cerebellar encephalopathy causing obstructive hydrocephalus
Authors: Verrees Meg , Filho Jose Americo Fernandes , Suarez Jose I. , Ratcheson Robert A. 
Published: May 2009

✓ Hypertension-induced encephalopathy is a recognized pathological process commonly focused in the parietal and occipital lobes of the cerebral hemispheres. The parenchyma of the posterior fossa is infrequently involved. The authors report on two cases of isolated edema of the cerebellar hemispheres, which occurred in the setting of hypertensive crisis and led to complete obstruction of or significant impingement on the fourth ventricle and potentially lethal hydrocephalus. To the best of the authors' knowledge, these are the first reported cases of hypertensive encephalopathy centered in the posterior fossa.
Two patients presented with profound decreases in neurological status subsequent to development of malignant hypertension. Imaging studies revealed diffusely edematous cerebellar hemispheres with effacement of the fourth ventricle, causing dilation of the lateral and third ventricles. Following emergency placement of external ventricular drains, control of systemic blood pressure was accomplished, and neurological functioning returned to baseline.
Although neurological deterioration resolved swiftly following placement of ventricular catheters and administration of diuretic agents, systemic blood pressure did not fluctuate with the release of cerebrospinal fluid and resolution of increased intracranial pressure. Decrease in systemic blood pressure lagged well behind improvement in neurological status; the patients remained morbidly hypertensive until systemic blood pressure was controlled with multiple parenteral medications.
The authors hypothesize that the development of hypertension beyond the limits of cerebral autoregulation led to breakdown of the blood—brain barrier in the cerebellum and development of posterior fossa edema secondary to the focal transudation of protein and fluid. Correction of the elevated blood pressure led to amelioration of cerebellar edema. In the appropriate clinical setting, hypertension as the inciting cause of cerebellar encephalopathy should be considered.
Percutaneous intracranial stent placement for aneurysms
Authors: Han Patrick P. , Albuquerque Felipe C. , Ponce Francisco A. , Mackay Christopher I. , Zabramski Joseph M. , Spetzler Robert F. , McDougall Cameron G. 
Published: May 2009

Object. Intracranial stent placement combined with coil embolization is an emerging procedure for the treatment of intracranial aneurysms. The authors report their results using intracranial stents for the treatment of intracranial aneurysms.
Methods. A prospectively maintained database was reviewed to identify all patients with intracranial aneurysms that were treated with intracranial stents. Ten lesions, including eight broad-based aneurysms and two dissecting aneurysms, were treated in 10 patients. Four lesions were located in the cavernous segment of the internal carotid artery, two at the vertebrobasilar junction, two at the basilar trunk, one at the basilar apex, and one in the intracranial vertebral artery. Attempts were made to place stents in 13 patients, but in three the stents could not be delivered. Altogether, intracranial stents were placed in 10 patients for 10 lesions.
Results that were determined to be satisfactory angiographically were achieved in all 10 lesions. Two patients suffered permanent neurological deterioration related to stent placement. In two patients, the aneurysm recurred after stent-assisted coil embolization. In one case of recurrence a second attempt at coil embolization was successful, whereas in the second case of recurrence parent vessel occlusion was required and well tolerated.
Conclusions. Intracranial stents can be a useful addition to coil embolization by providing mechanical, hemodynamic, and visual benefits in the treatment of complex, broad-based aneurysms.
Reduction in the number of repeated operations for the treatment of subacute and chronic subdural hematomas by placement of subdural drains
Authors: Lind Christopher R. P. , Lind Christina J. , Mee Edward W. 
Published: May 2009

Object. The aim of this study was to determine the influence of closed-system subdural drainage on repeated operation rates after burr hole evacuation of subacute and chronic subdural hematomas (SDHs).
Methods. Five hundred consecutive operations for the treatment of SDH via burr holes were performed between January 1, 1996, and April 15, 2002, at the Auckland Hospital. Hospital records were used to ascertain demographic data, operation, and repeated operation details. Rates of repeated surgeries were compared in patients with and without subdural drains.
Repeated operations were performed less frequently in patients with subdural drains, occurring in 31 (10%) of 310 cases involving drains and in 35 (19%) of 188 cases without drains (p < 0.01). Demographics between the two groups were not significantly different except for mean patient age, which was higher among patients with a subdural drain. A lower rate of repeated operation was observed in patients who had undergone drain placement, regardless of whether there was visible evidence of brain reexpansion.
Conclusions. Patients have lower rates of repeated surgeries if subdural drains are placed following evacuation of an SDH via a burr hole. To reach high clinical significance, 12 patients must undergo this simple intervention. If technically feasible, subdural drains should be inserted regardless of any occurrence of brain expansion during surgery.
Transcranial Doppler ultrasound study of the effects of nitrous oxide on cerebral autoregulation during neurosurgical anesthesia: a randomized controlled trial
Authors: Iacopino Domenico G. , Conti Alfredo , Battaglia Calogero , Siliotti Clotilde , Lucanto Tullio , Santamaria Letterio B. , Tomasello Francesco 
Published: May 2009

Object. Nitrous oxide has an adverse effect on cerebrovascular hemodynamics. Increased intracranial pressure, cerebral blood flow (CBF), cerebral metabolic rate of O2 (CMRO2), and reduced autoregulation indices have been reported, but their magnitudes are still being debated.
This study was designed to evaluate the effect of N2O on CBF and autoregulatory indexes during N2O—sevoflurane anesthesia in a prospective randomized controlled series of patients.
Methods. Two groups of 20 patients were studied on the basis of the use of N2O in the anesthetic gas mixture. The transient hyperemic response test, which relies on transcranial Doppler ultrasound techniques, was used to assess cerebral hemodynamics.
The time-averaged mean flow velocity, considered to be an index of actual CBF, increased significantly (p < 0.001) after introduction of N2O. The hyperemic response, considered as the index of autoregulatory potential, decreased significantly after introduction of N2O into the gas mixture (p < 0.001).
Conclusions. The increase in CBF and the reduction in autoregulatory indices suggest caution in using N2O during sevoflurane anesthesia, especially in patients with reduced autoregulatory reserve and during neurosurgical interventions. Transcranial Doppler ultrasonography is an efficacious method to evaluate the effects of anesthetic agents on CBF.
Bilateral subthalamic stimulation in patients with Parkinson disease: long-term follow up
Authors: Pahwa Rajesh , Wilkinson Steven B. , Overman John , Lyons Kelly E. 
Published: May 2009

Object. Bilateral subthalamic nucleus (STN) stimulation is increasingly used in patients with advanced Parkinson disease (PD). This study was performed to evaluate the long-term efficacy and safety of bilateral STN stimulation in cases of PD.
Methods. The authors performed a prospective, open-label study in patients with PD who underwent bilateral STN stimulation. The authors compared motor scores and activities of daily living (ADL) scores based on the Unified PD Rating Scale (UPDRS) obtained before surgery while patients were in the medication-off state with scores obtained at follow-up evaluations of these patients while in the medication-off/stimulator-on state. Data contained in patient diaries were also compared.
Thirty-three patients with PD were evaluated 12 months postoperatively and 19 were evaluated at a mean follow-up time of 28 months. A comparison between UPDRS scores obtained in patients in the medication-off/stimulator-on state and those obtained when patients were in the baseline medication-off state showed a 27% improvement in ADL scores and a 28% improvement in motor scores after surgery. There was a 57% reduction in the use of levodopa-equivalent medication doses. The percentage of the waking day that patients were in the medication-on state increased from 38 to 72%. Surgical complications included seizures (three patients), confusion (five patients), hemiballismus (one patient), and visual disturbance (one patient). Stimulation-related adverse effects were mild. Device-related events included nine lead replacements, seven lead revisions, six extension replacements, and 12 implantable pulse generator (IPG) replacements; one IPG was cleaned and one IPG was placed in a pocket because of the presence of a shunt.
Conclusions. Bilateral STN simulation is associated with a significant improvement in the motor features of PD. Device-related events were common in the first 20 patients who underwent surgery, often requiring repeated surgeries.
Loss of sensory discrimination after median nerve injury and activation in the primary somatosensory cortex on functional magnetic resonance imaging
Authors: Hansson Thomas , Brismar Tom 
Published: May 2009

Object. The aim of this study was to assess the effects of median nerve injury and regeneration on neuronal activation in the somatosensory cortex by means of functional magnetic resonance (fMR) imaging and somatosensory evoked potentials (SSEPs).
Methods. Ten injured male patients (mean age 26 years) were examined 15 to 58 months after a total transection of the median nerve at the wrist that was repaired with epineural sutures. Two-point discrimination was lost in Digit II–III and sensory nerve conduction displayed decreased velocity (−29%) and amplitude (−84%) in the median nerve at the wrist. The fMR images were obtained during tactile stimulation (gentle strokes) performed separately on the volar surface of either Digit II–III or Digit IV–V (eight patients: two were excluded because of movement artifacts). The SSEPs were obtained using electrical stimulation proximal to the median nerve lesion.
Conclusions. Patients with loss of sensory discrimination after median nerve damage and regeneration had larger areas of activation in fMR imaging near the contralateral central sulcus during tactile stimulation of the injured compared with the noninjured hand. The increase relative to the unaffected hand was 43% (p < 0.02) for Digit II–III stimulation and 46% (p < 0.02) for Digit IV–V stimulation. The SSEP data showed normal latency and amplitude. The enlarged area of cortical activation may be the result of reorganization, and it may indicate that larger cortical areas are involved in the discriminatory task after a derangement of the peripheral input.