bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting recovery in patients suffering from traumatic brain injury by using admission variables and physiological data: a comparison between decision tree analysis and logistic regression
Authors: Andrews Peter J. D. , Sleeman Derek H. , Statham Patrick F. X. , McQuatt Andrew , Corruble Vincent , Jones Patricia A. , Howells Timothy P. , Macmillan Carol S. A.
Published: May 2009

Object. Decision tree analysis highlights patient subgroups and critical values in variables assessed. Importantly, the results are visually informative and often present clear clinical interpretation about risk factors faced by patients in these subgroups. The aim of this prospective study was to compare results of logistic regression with those of decision tree analysis of an observational, head-injury data set, including a wide range of secondary insults and 12-month outcomes.

Methods. One hundred twenty-four adult head-injured patients were studied during their stay in an intensive care unit by using a computerized data collection system. Verified values falling outside threshold limits were analyzed according to insult grade and duration with the aid of logistic regression. A decision tree was automatically produced from root node to target classes (Glasgow Outcome Scale [GOS] score).

Among 69 patients, in whom eight insult categories could be assessed, outcome at 12 months was analyzed using logistic regression to determine the relative influence of patient age, admission Glasgow Coma Scale score, Injury Severity Score (ISS), pupillary response on admission, and insult duration. The most significant predictors of mortality in this patient set were duration of hypotensive, pyrexic, and hypoxemic insults. When good and poor outcomes were compared, hypotensive insults and pupillary response on admission were significant.

Using decision tree analysis, the authors found that hypotension and low cerebral perfusion pressure (CPP) are the best predictors of death, with a 9.2% improvement in predictive accuracy (PA) over that obtained by simply predicting the largest outcome category as the outcome for each patient. Hypotension was a significant predictor of poor outcome (GOS Score 1–3). Low CPP, patient age, hypocarbia, and pupillary response were also good predictors of outcome (good/poor), with a 5.1% improvement in PA. In certain subgroups of patients pyrexia was a predictor of good outcome.

Conclusions. Decision tree analysis confirmed some of the results of logistic regression and challenged others. This investigation shows that there is knowledge to be gained from analyzing observational data with the aid of decision tree analysis.
Implantation of deep brain stimulators into subthalmic nucleus: technical approach and magnetic imaging—verified electrode locations
Authors: Starr Philip A. , Christine Chadwick W. , Theodosopoulos Philip V. , Lindsey Nadja , Byrd Deborah , Mosley Anthony , Marks William J.
Published: May 2009

Object. Chronic deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a procedure that is rapidly gaining acceptance for the treatment of symptoms in patients with Parkinson disease (PD), but there are few detailed descriptions of the surgical procedure itself. The authors present the technical approach used to implant 76 stimulators into the STNs of patients with PD and the lead locations, which were verified on postoperative magnetic resonance (MR) images.

Methods. Implantation procedures were performed with the aid of stereotactic MR imaging, microelectrode recording (MER) in the region of the stereotactic target to define the motor area of the STN, and intraoperative test stimulation to assess the thresholds for stimulation-induced adverse effects. All patients underwent postoperative MR imaging, which was performed using volumetric gradient-echo and T2-weighted fast—spin echo techniques, computational reformatting of the MR image into standard anatomical planes, and quantitative measurements of lead location with respect to the midcommissural point and the red nucleus. Lead locations were statistically correlated with physiological data obtained during MER and intraoperative test stimulation.

Conclusions. The authors' approach to implantation of DBS leads into the STN was associated with consistent lead placement in the dorsolateral STN, a low rate of morbidity, efficient use of operating room time, and robust improvement in motor function. The mean coordinates of the middle of the electrode array, measured on postoperative MR images, were 11.6 mm lateral, 2.9 mm posterior, and 4.7 mm inferior to the midcommissural point, and 6.5 mm lateral and 3.5 mm anterior to the center of the red nucleus. Voltage thresholds for several types of stimulation-induced adverse effects were predictive of lead location. Technical nuances of the surgery are described in detail.
Anatomical analysis of different hemispherotomy procedures based on dissection of cadaveric brains
Authors: Morino Michiharu , Shimizu Hiroyuki , Ohata Kenji , Tanaka Kiyoaki , Hara Mitsuhiro
Published: May 2009

Object. Functional hemispherectomy, itself a modification of anatomical hemispherectomy, has been further modified to a less invasive method (hemispherotomy), in which cortical resection is minimized and the rest of the affected hemisphere is functionally isolated by transecting its projection and commissural fibers. Although descriptions of three different types of hemispherotomy procedures have been published, the authors believe that it is important to develop a common and universally acceptable method based on a systematic analysis of topographic anatomy and neuronal connections. To this end, they have analyzed the three aforementioned procedures on the basis of meticulous fiber dissections in previously frozen formalin-fixed human brains.

Methods. The brain anatomy pertinent to surgical hemispherotomy is described in conjunction with dissection studies in 14 previously frozen, formalin-fixed human brains. The anatomical landmarks necessary for performing particular neuronal fiber resections are identified, and their relationships with operative methods are discussed, with an emphasis on commonalities among the three hemispherotomy procedures.

Conclusions. In this analysis the authors confirmed that hemispherotomy typically consists of four common procedures: 1) interruption of the internal capsule and corona radiata; 2) resection of the medial temporal structures; 3) transventricular corpus callosotomy; and 4) disruption of the frontal horizontal fibers. After meticulous dissection of cadavers, the authors have designated a reliable method for performing these four operations that may be applicable as a commonly used procedure.
Camptocormia treated with bilateral pallidal stimulation
Authors: Nandi Dipankar , Parkin Simon , Scott Richard , Winter Jonathan L. , Joint Carole , Gregory Ralph , Stein John , Aziz Tipu Z.
Published: May 2009

✓ The authors report the neurological, neurophysiological, and neuropsychological effects of using long-term bilateral pallidal high-frequency deep brain stimulation (DBS) in a case of disabling camptocormia. Deep brain stimulation electrodes were implanted stereotactically to target the globus pallidus internus (GPi) bilaterally. Local field potentials (FPs) were recorded using the DBS electrodes and concurrent abdominal flexor electromyography (EMG) potentials during camptocormic episodes. Videotaped assessments of the movement disorder and neuropsychological evaluations of the patient before implantation and 6 months after initiation of pallidal stimulation were recorded.

There was significant functional improvement following long-term pallidal stimulation, and some improvement was noted in neuropsychological scores. A temporal correlation between the GPi FPs and EMG-recorded rectus abdominis potentials was evident. There were no treatment-related adverse effects. The authors have found that long-term pallidal stimulation was safe and offered functional benefit to a patient with this severely disabling condition. The physiological studies may help further the understanding of the pathophysiology of this rare entity.
Carpal tunnel syndrome caused by thrombosis of the median artery: importance of high-resolution ultrasonography for diagnosis
Authors: Kele Henrich , Verheggen Raphaela , Reimers Carl Detlev
Published: May 2009

✓ The rare case of a patient with carpal tunnel syndrome caused by thrombosis of a persistent median artery is presented. Progressive pain in the wrist and dysesthesias in the third and fourth fingers were the atypical complaints. High-resolution ultrasonography revealed a bifid median nerve that was compressed by an occluded median artery. The intraoperative findings are described, and emphasis is placed on the importance of using high-resolution ultrasonography for presurgical diagnosis.
Functional performance following selective posterior rhizotomy: long-term results determined using a validated evaluative measure
Authors: Mittal Sandeep , Farmer Jean-Pierre , Al-Atassi Borhan , Montpetit Kathleen , Gervais Nathalie , Poulin Chantal , Benaroch Thierry E. , Cantin Marie-André
Published: May 2009

Object. Selective posterior rhizotomy (SPR) may result in considerable benefit for children with spastic cerebral palsy. To date, however, there have been few studies in which validated functional outcome measures have been used to report surgical results beyond 3 years. The authors analyzed data obtained from the McGill Rhizotomy Database to determine long-term functional performance outcomes in patients who underwent lumbosacral dorsal rhizotomy performed using intraoperative electrophysiological monitoring.

Methods. The study population was composed of children with debilitating spasticity who underwent SPR and were evaluated by a multidisciplinary team preoperatively and at 6 months and 1 year postoperatively. Quantitative standardized assessments of activities of daily living (ADL) were obtained using the Pediatric Evaluation of Disability Inventory (PEDI). Of 57 patients who met the entry criteria for the study, 41 completed the 3-year assessments and 30 completed the 5-year assessments.

Statistical analysis demonstrated significant improvement in the mobility and self-care domains of the functional skills dimension at 1 year after SPR. The preoperative and 1-, 3-, and 5-year postoperative scaled scores for the mobility domain were 56, 64, 77.2, and 77.8, respectively. The scaled score for the self-care domain increased from 59 presurgery to 67.9, 81.6, and 82.4 at the 1-, 3-, and 5-year postoperative assessments, respectively.

Conclusions. The results of this study support the presence of significant improvements in functional performance, based on PEDI scores obtained 1 year after SPR. The improvements persisted at the 3- and 5-year follow-up examinations. The authors conclude that SPR performed using intraoperative stimulation is valuable in the augmentation of motor function and self-care skills essential to the performance of ADL.
Endoscopic third ventriculostomy in patients with cerebrospinal fluid infection and/or hemorrhage
Authors: Siomin Vitaly , Cinalli Giuseppe , Grotenhuis Andre , Golash Aprajay , Oi Shizuo , Kothbauer Karl , Weiner Howard , Roth Jonathan , Beni-Adani Liana , Pierre-Kahn Alain , Takahashi Yasuhiro , Mallucci Connor , Abbott Rick , Wisoff Jeffrey , Constantini Shlomi
Published: May 2009

Object. In this study the authors evaluate the safety, efficacy, and indications for endoscopic third ventriculostomy (ETV) in patients with a history of subarachnoid hemorrhage or intraventricular hemorrhage (IVH) and/or cerebrospinal fluid (CSF) infection.

Methods. The charts of 101 patients from seven international medical centers were retrospectively reviewed; 46 patients had a history of hemorrhage, 42 had a history of CSF infection, and 13 had a history of both disorders. All patients experienced third ventricular hydrocephalus before endoscopy. The success rate for treatment in these three groups was 60.9, 64.3, and 23.1%, respectively. The follow-up period in successfully treated patients ranged from 0.6 to 10 years. Relatively minor complications were observed in 15 patients (14.9%), and there were no deaths. A higher rate of treatment failure was associated with three factors: classification in the combined infection/hemorrhage group, premature birth in the posthemorrhage group, and younger age in the postinfection group. A higher success rate was associated with a history of ventriculoperitoneal (VP) shunt placement before ETV in the posthemorrhage group, even among those who had been born prematurely, who were otherwise more prone to treatment failure. The 13 premature infants who had suffered an IVH and who had undergone VP shunt placement before ETV had a 100% success rate. The procedure was also successful in nine of 10 patients with primary aqueductal stenosis.

Conclusions. Patients with obstructive hydrocephalus and a history of either hemorrhage or infection may be good candidates for ETV, with safety and success rates comparable with those in more general series of patients. Patients who have sustained both hemorrhage and infection are poor candidates for ETV, except in selected cases and as a treatment of last resort. In patients who have previously undergone shunt placement posthemorrhage, ETV is highly successful. It is also highly successful in patients with primary aqueductal stenosis, even in those with a history of hemorrhage or CSF infection.
Results of stereotactic radiosurgery in patients with hormone-producing pituitary adenomas: factors associated with endocrine normalization
Authors: Pollock Bruce E. , Nippoldt Todd B. , Stafford Scott L. , Foote Robert L. , Abboud Charles F.
Published: May 2009

Object. The goal of this study was to determine factors associated with endocrine normalization after radiosurgery is performed in patients with hormone-producing pituitary adenomas.

Methods. Between 1990 and 1999, 43 patients with hormone-producing pituitary adenomas underwent radiosurgery: 26 patients with growth hormone (GH)—producing tumors, nine with adrenocorticotrophic hormone—producing tumors, seven with tumors that produced prolactin (PRL) alone, and one with a tumor that secreted both GH and PRL. The median patient age was 42 years. Thirty-seven patients (86%) had undergone surgery earlier and in 30 (70%) there was tumor extension into the cavernous sinus. The product-limit method was used to calculate endocrine normalization while patients were not receiving any hormone-suppressive medication. The median follow-up period after radio-surgery was 36 months (range 12–108 months).

In 20 patients (47%) there was normalization of hormone secretion at a median of 14 months (range 2–44 months) after radiosurgery; no correlation was found between tumor type and cure. Actuarial cure rates were 20, 32, and 61% at 1, 2, and 4 years posttreatment. Multivariate analysis demonstrated that the absence of hormone-suppressive medications at the time of radiosurgery (relative risk 8.9, 95% confidence interval [CI] 1.2–68.7, p = 0.04) and maximum radiation doses greater than 40 Gy (relative risk 3.9, 95% CI 1.3–11.7, p = 0.02) correlated with an endocrine cure. A new anterior pituitary deficiency developed in seven patients (16%), temporal lobe necrosis was identified in two patients, an asymptomatic internal carotid artery stenosis was detected in two patients, and unilateral blindness occurred in one patient.

Conclusions. Radiosurgery provides an endocrine cure for many patients with persistent or recurrent hormone-producing pituitary adenomas. Further study is needed to determine whether pituitary hormone—suppressive medications have a radioprotective effect.
Prediction of death in patients with primary intracerebral hemorrhage: a prospective study of a defined population
Authors: Nilsson Ola G. , Lindgren Arne , Brandt Lennart , Säveland Hans
Published: May 2009

Object. Predictors of early (30-day) and long-term (1-year) mortality rates after primary intracerebral hemorrhage (ICH) were studied in a large population in southern Sweden.

Methods. All cases of primary ICH, verified using computerized tomography (CT) scanning or autopsy study, were prospectively registered at the 12 hospitals covering a defined population of 1.14 million during the calendar year 1996. Mortality was analyzed in relation to CT findings (hematoma location and volume and ventricular extension) and clinical parameters (patient age and sex, level of consciousness on admission, and history of preictal risk factors) by using univariate and multivariate statistical methods.

Three hundred forty-one cases of primary ICH were detected. The overall mortality rate was 36% at the 30-day and 47% at the 1-year follow up. Multivariate analysis revealed that initial level of consciousness, hematoma volume, and a history of heart disease were independent predictors of death at 30 days postictus. One year after bleeding, independent predictors of mortality were the initial level of consciousness, patient age, and hematoma location.

Conclusions. Primary ICH remains a stroke subtype associated with a high mortality rate and for which the level of consciousness on admission is the strongest predictor of fatal outcome both at 30 days and during the 1st year after bleeding. A preictal history of heart disease increased the 30-day mortality rate.
Rise in serum soluble intercellular adhesion molecule—1 levels with vasospasm following aneurysmal subarachnoid hemorrhage
Authors: Mocco J , Mack William J. , Kim Grace H. , Lozier Alan P. , Laufer Ilya , Kreiter Kurt T. , Sciacca Robert R. , Solomon Robert A. , Mayer Stephan A. , Connolly E. Sander
Published: May 2009

Object. Proinflammatory adhesion molecule expression has been demonstrated to be elevated in patients with aneurysmal subarachnoid hemorrhage (SAH). Recent studies have shown that elevations in soluble intercellular adhesion molecule—1 (ICAM-1) may be predictive of poor outcome in patients with good grade (Hunt and Hess Grades 1–2) aneurysmal SAH at delayed time points that correspond with the risk period for cerebral vasospasm. In addition, ICAM-1 is upregulated in experimental models of vasospasm. Unfortunately, the relationship of adhesion molecule expression to human vasospasm remains unclear. The authors hypothesized that the delayed elevation of soluble ICAM-1 in patients with aneurysmal SAH is associated with the development of cerebral vasospasm.

Methods. Eighty-nine patients with aneurysmal SAH were prospectively enrolled in a study and stratified according to the presence or absence of vasospasm, as evidenced by daily monitoring of transcranial Doppler (TCD) velocities (presence, > 200 cm/second; absence, ≤ 120 cm/second). Levels of soluble ICAM-1 were determined using enzyme-linked immunosorbent assay every other day for 12 days post-SAH. An analysis of covariance model was used to evaluate trends in soluble ICAM-1 levels from 2 days prior to 6 days after the occurrence of documented vasospasm. Two groups of patients, matched for admission admission Hunt and Hess grade, were compared: nine patients with TCD velocities greater than 200 cm/second and nine patients with TCD velocities less than 120 cm/second. From among the patients with TCD velocities greater than 200 cm/second six patients with angiographically documented vasospasm were selected. Patients with TCD velocities less than 120 cm/second and matched admission Hunt and Hess grades but without angiographically documented vasospasm were selected. Patients with TCD-demonstrated vasospasm showed a significant mean rate of rise (p < 0.01) in soluble ICAM-1 levels during the perivasospasm period, but admission Hunt and Hess grade—matched control patients did not (p = not significant [NS]). There was a significant difference between these groups' rates of soluble ICAM increase (p < 0.01). Patients with both TCD- and angiographically demonstrated vasospasm likewise showed a highly significant mean rate of increase in soluble ICAM-1 levels during the perivasospasm period (p < 0.01), whereas admission Hunt and Hess grade—matched controls did not (p = NS). The difference beween these groups' rates of increase was highly significant (p < 0.001).

Conclusions. These data suggest a role for ICAM-1 in the pathophysiology of cerebral vasospasm or its ischemic sequelae. As this relationship is further elucidated, adhesion molecules such as ICAM-1 may provide novel therapeutic targets in the prevention of vasospasm or its ischemic consequences.
Mechanisms of snowboarding-related severe head injury: shear strain induced by the opposite-edge phenomenon
Authors: Nakaguchi Hiroshi , Tsutsumi Kazuo
Published: May 2009

Object. To date, there has been no published study in which the focus was on the mechanisms of head injuries associated with snowboarding. The purpose of this study was to identify these mechanisms.

Methods. The patient population consisted of 38 consecutive patients with snowboarding-related major head injuries who were treated at two hospitals in Japan, where for years many winter sports injuries have been treated. The skill level of the snowboarder, the cause of the accident, the direction of the fall, the site of impact to the head, and the condition of the ski slope were examined. The injuries were classified as coup, contrecoup, or shear injuries.

The predominant features of snowboarding-related major head injuries included: falling backward (68% of cases), occipital impact (66% of cases), a gentle or moderate ski slope (76% of cases), and inertial injury (76% of cases [shear injury in 68% and contrecoup injury in 8% of the patients]). Acute subdural hematoma frequently occurred after a patient fell on the slope (p = 0.025), fell backward (p = 0.0014), or received an occipital impact (p = 0.0064). Subcortical hemorrhagic contusions frequently occurred after the patient fell during a jump (p = 0.0488), received a temporal impact (p = 0.0404), or fell on the jump platform (p = 0.0075). Shear injury frequently occurred after a fall that occurred during a jump or after simple falls on the ski slope, and contact injury was frequently seen after a collision (p = 0.0441).

Conclusions. The majority of severe head injuries associated with snowboarding that occur after a simple fall on the slope are believed to involve the opposite-edge phenomenon, which results from a fall backward on a gentle or moderate slope causing occipital impact. The use of a device to protect the occiput is proposed to reduce head injuries associated with snowboarding.
Subthalamotomy for advanced Parkinson disease
Authors: Su Philip C. , Tseng Ham-Min , Liu Hon-Man , Yen Ruoh-Fang , Liou Horng-Huei
Published: May 2009

Object. The aim of this study was to determine if subthalamotomy is effective in treating advanced Parkinson disease (PD).

Methods. The authors performed microelectrode mapping—guided stereotactic surgery on the subthalamic nucleus in eight patients with PD. Lesioning was performed using radiofrequency heat coagulation and confirmed with magnetic resonance imaging. Three patients who underwent unilateral and four with bilateral subthalamotomy were evaluated for up to 18 months according to the Unified PD Rating Scale (UPDRS). One patient who underwent unilateral subthalamotomy died 6 months postsurgery.

At 3 months into the “off” period after surgery, there were significant improvements in contralateral bradykinesia (p < 0.0002), rigidity (p < 0.0001), tremor (p < 0.01), axial motor features (p < 0.02), gait (p < 0.03), postural stability (p < 0.03), total UPDRS scores (p < 0.03), and Schwab and England scores (p < 0.04). The benefits were sustained at 6, 12, and 18 months, except for the improvement in tremor. At 12 months into the “on” period, significant benefits were present for motor fluctuation (p < 0.04), on dyskinesia (p < 0.006), off duration (p < 0.05), total UPDRS score (p < 0.02), and contralateral tremor (p < 0.05). Benefits for motor fluctuation, off duration, and off-period tremor were lost after the 18-month follow-up period. The levodopa requirement was reduced by 66% for the unilateral and 38% for the bilaterally treated group. Bilateral subthalamotomy offered more benefits than did unilateral surgery for various parkinsonian features in both the on and off periods. Three patients suffered hemiballismus, two recovered spontaneously, and one died of aspiration pneumonia after discontinuation of levodopa.

Conclusions. These findings indicate that subthalamotomy can ameliorate the cardinal symptoms of PD, reduce the dosage of levodopa, diminish complications of the drug therapy, and improve the quality of life.
Expression of hypoxia inducible factor—1 alpha and correlation with preoperative embolization of meningiomas
Authors: Jensen Randy L. , Soleau Scott , Bhayani Mihir K. , Christiansen Dustin
Published: May 2009

Object. Vascular endothelial growth factor (VEGF) has been implicated in meningioma tumorigenesis and growth. The production of VEGF is regulated by hypoxia inducible factor—1α (HIF-1α), especially under conditions of hypoxia. In this study, the authors examine the expression of HIF-1α and VEGF in meningiomas, with a special emphasis on conditions of hypoxia, such as preoperative embolization, and on in vitro studies in cultured cells.

Methods. Meningiomas obtained in 142 patients were studied using immunohistochemical methods to detect HIF-1α and the results were correlated with the extent or lack of preoperative embolization and expression of VEGF. Primary meningioma cell cultures were established and cell culture experiments were performed using a hypoxia chamber to stimulate HIF-1α and VEGF production. Expression of HIF-1α in primary meningioma cell cultures was measured using immunoblot assays. The VEGF secretion was measured using enzyme-linked immunosorbent assay.

Half of the meningiomas studied were positive for HIF-1α, with a strong correlation between complete embolization and HIF-1α expression. Most of the meningiomas studied expressed VEGF protein, and VEGF expression did not correlate with the degree of embolization. A strong correlation was found between VEGF and HIF-1α expression in immunohistochemical studies. Secretion of VEGF is increased by hypoxia and growth factor stimulation. In meningiomas, growth factors stimulate HIF-1α expression. The role of hypoxia is less clear.

Conclusions. The expression of HIF-1α is increased by complete preoperative embolization of meningiomas. The expression of HIF-1α also correlates with VEGF secretion in meningiomas. Growth factor and hypoxic stimulation both contribute to VEGF control, but which is most important (or whether both are equally important) will require further studies.
Evidence for phosphatidylinositol 3-kinase—Akt—p70S6K pathway activation and transduction of mitogenic signals by platelet-derived growth factor in human meningioma cells
Authors: Johnson Mahlon D. , Okediji Evelyn , Woodard Ann , Toms Steven A. , Allen George S.
Published: May 2009

Object. The intracellular events transducing mitogenic signals from platelet-derived growth factor—β (PDGFβ) receptor tyrosine kinases are not precisely known. In this study the authors evaluated whether the phosphatidylinositol 3-kinase (PI3-K)—Akt—p70S6K pathway is expressed in meningiomas, regulates their growth, and transduces mitogenic signals of PDGF-BB.

Methods. Nine meningioma tumors obtained in humans were evaluated using Western blot analysis for phosphorylated (activated) Akt and phosphorylated p70S6K. Cells cultured from seven of these meningiomas were also screened using Western blot analysis for Akt and for phosphorylated Akt and p70S6K. The authors also evaluated whether PDGF-BB stimulation of meningioma cells was associated with the phosphorylation of Akt and p70S6K known to activate these kinases. In addition, the effects of wortmannin, an inhibitor of PI3-K, on proliferation and activation of Akt and p70S6K in meningioma cells stimulated with PDGF-BB were evaluated.

Western blots of lysates from meningiomas demonstrated phosphorylated Akt and p70S6K. Treatment with PDGF-BB stimulated phosphorylation of Akt and p70S6K in each meningioma cell culture. Wortmannin (500 and 1000 nM) significantly decreased PDGF-BB stimulation of meningioma cells (p < 0.001) while it reduced Akt and p70S6K phosphorylation but not mitogen-activated protein kinase/extracellular signal—regulated kinase (MAPK/ERK) phosphorylation.

Conclusions. These findings indicate that Akt and p70S6K are constitutively expressed and activated in meningioma cells and that the PI3-K—Akt—p70S6K pathway may participate in transduction of mitogenic signals in meningiomas independent of the Raf-1—MEK-1—MAPK/ERK cascade.
Seeding of malignant meningioma along a surgical trajectory on the scalp
Authors: Lüdemann Wolf O. , Obler Richard , Tatagiba Marcos , Samii Madjid
Published: May 2009

✓ The authors report the case of an 11-year-old boy with a malignant meningioma of the right frontal meninges. The tumor was asymptomatic, despite visible exophytic extracranial growth. Neuroimaging demonstrated an en plaque meningioma bulging into the brain. Six months after the tumor had been totally removed by surgery, an isolated subcutaneous metastasis developed at the right preauricular area of the scalp, originating at the scar left by the first surgery. After removal of this metastasis, radiotherapy was conducted.

To date the follow-up examinations have not revealed any additional metastases. To the best of the authors' knowledge, this is the first report of a seeding of a subcutaneous metastasis in a child with a malignant meningioma. The authors review the literature with reference to malignant meningiomas and their formation of metastasis.

In cases of malignant meningiomas, piecemeal tumor removal carries the risk of iatrogenic cell dissemination even when precautions are taken.
Distal anterior inferior cerebellar artery aneurysms
Authors: Zager Eric L. , Shaver Ellen G. , Hurst Robert W. , Flamm Eugene S.
Published: May 2009

✓ Aneurysms of the distal anterior inferior cerebellar artery (AICA) are rare; fewer than 100 cases have been reported. The authors detail their experience with four cases and present endovascular as well as microsurgical management options.

The medical records and neuroimaging studies obtained in four patients who were treated at a single institution were reviewed. Clinical presentations, neuroimaging and intraoperative findings, and clinical outcomes were analyzed.

There were three men and one woman; their mean age was 43 years. Two patients presented with acute subarachnoid hemorrhage (SAH), and two presented with ataxia and vertigo (one with tinnitus, the other with hearing loss). Angiographic studies demonstrated aneurysms of the distal segment of the AICA. In one patient with von Hippel—Lindau syndrome and multiple cerebellar hemangioblastomas, a feeding artery aneurysm was found on a distal branch of the AICA. Three of the patients underwent successful surgical obliteration of their aneurysms, one by clipping, one by trapping, and one by resection along with the tumor. The fourth patient underwent coil embolization of the distal AICA and the aneurysm. All patients made an excellent neurological recovery.

Patients with aneurysms in this location may present with typical features of an acute SAH or with symptoms referable to the cerebellopontine angle. Evaluation with computerized tomography, magnetic resonance (MR) imaging, MR angiography, and digital subtraction angiography should be performed. For lesions distal to branches coursing to the brainstem, trapping and aneurysm resection are viable options that do not require bypass. Endovascular obliteration is also a reasonable option, although the possibility of retrograde thrombosis of the AICA is a concern.
Neurological deterioration after coil embolization of a giant basilar apex aneurysm with resolution following parent artery clip ligation
Authors: Russell Stephen M. , Nelson P. Kim , Jafar Jafar J.
Published: May 2009

✓ The authors present the case of a patient who suffered from progressive cranial nerve dysfunction, radiographically documented brainstem compression, and peduncular hallucinosis after undergoing endosaccular coil placement in a giant basilar apex aneurysm. Symptom resolution was achieved following clip ligation of the basilar artery. The pathogenesis of aneurysm mass effect due to coil placement is discussed and the pertinent literature is reviewed.
Retrospective analysis of a 10-year experience of stereotactic radiosurgery for arteriovenous malformations in children and adolescents
Authors: Shin Masahiro , Kawamoto Shunsuke , Kurita Hiroki , Tago Masao , Sasaki Tomio , Morita Akio , Ueki Keisuke , Kirino Takaaki
Published: May 2009

Object. To obtain information essential to the decision to perform radiosurgery for arteriovenous malformations (AVMs) in children and adolescents, the authors retrospectively analyzed their experience with gamma knife surgery for AVMs in 100 patients ranging in age from 4 to 19 years.

Methods. Follow-up periods ranged from 6 to 124 months (median 71 months), and the actuarial obliteration rates demonstrated by angiography were 84.1, 89.4, and 94.7% at 3, 4, and 5 years, respectively. Factors associated with better obliteration rates in univariate analysis included the following: a patient age of 12 years or younger; a mean nidus diameter of 2 cm or less; a nidus volume of 3.8 cm3 or less; a maximum diameter of the nidus less than 3 cm; and a Spetzler—Martin grade of III or less. Radiation-induced neuropathy was seen in four patients, and the risk factors were considered to be a nidus in the brainstem and a maximum radiation dose greater than 40 Gy. Hemorrhage developed during the latency interval in four patients, and one patient with a cerebellar AVM died of the hemorrhage. The annual bleeding rate was 1.5%. Feeding arteries located in the posterior cranial fossa and an AVM nidus located in the cerebellum were significantly associated with the risk of hemorrhage. After angiographically verified obliteration of the nidus, 51 patients continued to be observed from 1 to 110 months (median 67 months); hemorrhage developed in one patient 38 months after nidus obliteration.

Conclusions. Radiosurgery is an acceptable treatment for small AVMs in children and adolescents in whom a higher obliteration rate can be achieved with lower risks of interval hemorrhage compared with the reported results in the general population. Careful follow-up observation seems to be required, however, even after angiographically verified obliteration.
Organ donation rates in a neurosurgical intensive care unit
Authors: Dickerson John , Valadka Alex B. , LeVert Tina , Davis Kimberly , Kurian Mary , Robertson Claudia S.
Published: May 2009

Object. The number of patients waiting for organ transplantation continues to grow, while organs are donated by very few of the thousands of potential donors who die every year. The authors' neurosurgical intensive care unit (NICU) has worked closely with coordinators from the local organ procurement organization (OPO) for many years. In this study, the authors analyze donation rates in the NICU and discuss factors that may be important in maximizing these rates.

Methods. All referrals from the NICU to the OPO from 1996 to 1999 were analyzed. Of the 180 referrals, 98 patients were found to be medically suitable as potential donors. Another 15 patients died of hemodynamic collapse shortly after admission to the NICU. If one assumes that all 15 patients would have been suitable donors, the unsuccessful resuscitation rate becomes 15 (13.3%) of 113. Of the 98 eligible donors, consent was obtained and organs or tissue were recovered in 72, yielding a successful organ procurement rate of 73.5%.

Conclusions. Close working relationships among physicians, nurses, and OPO coordinators can result in higher donation rates than have been reported previously. Aggressive resuscitation and stabilization of all patients, early identification of potential organ donors, prompt declaration of brain death, and attempts by the OPO coordinator to build rapport with families are all important factors that may increase donation rates. Because most organ donors have sustained catastrophic intracranial events, neurosurgeons are uniquely positioned to influence organ donation policies at their hospitals and thus to salvage some benefit from tragic cases of overwhelming brain injury.
Temporary arterial occlusion in the repair of ruptured intracranial aneurysms: an analysis of risk factors for stroke
Authors: Ferch Richard , Pasqualin Alberto , Pinna Giampietro , Chioffi Franco , Bricolo Albino
Published: May 2009

Object. This study was performed to further elucidate technical and patient-specific risk factors for perioperative stroke in patients undergoing temporary arterial occlusion during the surgical repair of their aneurysms.

Methods. One hundred twelve consecutive patients in whom temporary arterial occlusion was performed during surgical repair of an aneurysm were retrospectively analyzed. Confounding factors (inadvertent permanent vessel occlusion and retraction injury) were identified in six cases (5%) and these were excluded from further analysis. The demographics for the remaining 106 patients were analyzed with respect to age, neurological status, aneurysm characteristics, intraoperative rupture, duration of temporary occlusion, and number of occlusive episodes; end points considered were outcome at 3-month follow up and symptomatic and radiological stroke.

Conclusions. Overall 17% of patients experienced symptomatic stroke and 26% had radiological evidence of stroke attributable to temporary arterial occlusion. A longer duration of clip placement, older patient age, a poor clinical grade (Hunt and Hess Grades IV–V), early surgery, and the use of single prolonged clip placement rather than repeated shorter episodes were associated with a higher risk of stroke based on univariate analysis. Intraoperative aneurysm rupture did not affect stroke risk. On multivariate analysis, only poorer clinical grade (p = 0.001) and increasing age (p = 0.04) were significantly associated with symptomatic stroke risk.
Effects of the nitric oxide donor 3-morpholinosydnonimine (SIN-1) in focal cerebral ischemia dependent on intracellular brain pH
Authors: Coert Bernard A. , Anderson Robert E. , Meyer Fredric B.
Published: May 2009

Object. A nitric oxide (NO) donor that has been successfully used in the treatment of myocardial infarction, 3-morpholinosydnonimine (SIN-1), may be a potential neuroprotective agent. Production of NO in brain microsomes is dependent on the pH. The purpose of this study was to determine the efficacy of SIN-1 and its dependence on pH in vivo during periods of focal cerebral ischemia.

Methods. At 0.1 or 1 mg/kg, SIN-1 was administered to 54 Wistar rats 30 minutes before a 2-hour period of focal cerebral ischemia under moderate hypo-, normo-, and hyperglycemic conditions. Measurements of brain intracellular pH (pHi); regional cortical blood flow, and the redox state of nicotinamide adenine dinucleotide were obtained in three additional animals to confirm the effects of the serum glucose manipulations. The animals were killed at 72 hours after the ischemic period to obtain infarction volumes. Administration of SIN-1 significantly reduced infarction in normoglycemic animals and, to a lesser extent, in hyperglycemic animals, indicating that SIN-1 was less effective under hyperglycemic conditions. At either dose SIN-1 had no significant effect on infarction volume in moderately hypoglycemic animals because moderate hypoglycemia in itself significantly (p < 0.005) reduced infarction volume.

Conclusions. The NO donor SIN-1 may be a useful intraoperative cerebral protective agent. Furthermore, it is hypothesized that a mechanism that could explain the published discrepancies regarding the effects of NO donors in vivo may be affected by differences in ischemic brain acidosis.
Excimer laser—assisted bypass in aneurysm treatment: short-term outcomes
Authors: Brilstra Eva H. , Rinkel Gabriel J. E. , Klijn Catharina J. M. , van der Zwan Albert , Algra Ale , Lo Rob T. H. , Tulleken Cornelis A. F.
Published: May 2009

Object. If clip application or coil placement for treatment of intracranial aneurysms is not feasible, the parent vessel can be occluded to induce thrombosis of the aneurysm. The Excimer laser—assisted anastomosis technique allows the construction of a high-flow bypass in patients who cannot tolerate such an occlusion. The authors assessed the complications of this procedure and clinical outcomes after the construction of high-flow bypasses in patients with intracranial aneurysms.

Methods. Data were retrospectively collected on patient and aneurysm characteristics, procedural complications, and functional outcomes in 77 patients in whom a high-flow bypass was constructed. Logistic regression analysis was used to quantify the relationships between patient and aneurysm characteristics on the one hand and outcome measures on the other.

Fifty-one patients harbored a giant aneurysm, 24 patients suffered from a ruptured aneurysm, and 35 patients from an unruptured symptomatic aneurysm. In 22 patients (29%; 95% confidence interval [CI] 19–40%) a permanent deficit developed from an operative complication. At a median follow-up period of 2.5 months, 25 patients (32%; 95% CI 22–44%) were dependent or had died; in 10 of these patients (13% of all patients; 95% CI 6–23%) operative complications were the single cause of this poor outcome. Univariate analysis demonstrated that a poor clinical condition before treatment (odds ratio [OR] 4.7; 95% CI 1.7–13.3) and a history of cardiovascular disease (OR 4.1; 95% CI 1–16.2) increased the risk of poor outcome. Multivariate analysis demonstrated that only the clinical condition before treatment was significantly related to outcome (OR 4; 95% CI 1.3–11.9).

Conclusions. In patients with an intracranial aneurysm that cannot be treated by clip application or coil placement, and in whom occlusion of the parent artery cannot be tolerated, the construction of a high-flow bypass should be considered. This procedure carries a considerable risk of complications, but this should be weighed against the disabling or life-threatening effects of compression, the high risk of rupture, and the substantial chance of poor outcome after the rupture of such aneurysms.
Efficacy of hyperventilation, blood pressure elevation, and metabolic suppression therapy in controlling intracranial pressure after head injury
Authors: Oertel Matthias , Kelly Daniel F. , Lee Jae Hong , McArthur David L. , Glenn Thomas C. , Vespa Paul , Boscardin W. John , Hovda David A. , Martin Neil A.
Published: May 2009

Object. Hyperventilation therapy, blood pressure augmentation, and metabolic suppression therapy are often used to reduce intracranial pressure (ICP) and improve cerebral perfusion pressure (CPP) in intubated head-injured patients. In this study, as part of routine vasoreactivity testing, these three therapies were assessed in their effectiveness in reducing ICP.

Methods. Thirty-three patients with a mean age of 33 ± 13 years and a median Glasgow Coma Scale (GCS) score of 7 underwent a total of 70 vasoreactivity testing sessions from postinjury Days 0 to 13. After an initial 133Xe cerebral blood flow (CBF) assessment, transcranial Doppler ultrasonography recordings of the middle cerebral arteries were obtained to assess blood flow velocity changes resulting from transient hyperventilation (57 studies in 27 patients), phenylephrine-induced hypertension (55 studies in 26 patients), and propofol-induced metabolic suppression (43 studies in 21 patients). Changes in ICP, mean arterial blood pressure (MABP), CPP, PaCO2, and jugular venous oxygen saturation (SjvO2) were recorded. With hyperventilation therapy, patients experienced a mean decrease in PaCO2 from 35 ± 5 to 27 ± 5 mm Hg and in ICP from 20 ± 11 to 13 ± 8 mm Hg (p < 0.001). In no patient who underwent hyperventilation therapy did SjvO2 fall below 55%. With induced hypertension, MABP in patients increased by 14 ± 5 mm Hg and ICP increased from 16 ± 9 to 19 ± 9 mm Hg (p = 0.001). With the aid of metabolic suppression, MABP remained stable and ICP decreased from 20 ± 10 to 16 ± 11 mm Hg (p < 0.001). A decrease in ICP of more than 20% below the baseline value was observed in 77.2, 5.5, and 48.8% of hyperventilation, induced-hypertension, and metabolic suppression tests, respectively (p < 0.001 for all comparisons). Predictors of an effective reduction in ICP included a high PaCO2 for hyperventilation, a high study GCS score for induced hypertension, and a high PaCO2 and a high CBF for metabolic suppression.

Conclusions Of the three modalities tested to reduce ICP, hyperventilation therapy was the most consistently effective, metabolic suppression therapy was variably effective, and induced hypertension was generally ineffective and in some instances significantly raised ICP. The results of this study suggest that hyperventilation may be used more aggressively to control ICP in head-injured patients, provided it is performed in conjunction with monitoring of SjvO2.
Dynamic autoregulatory response after severe head injury
Authors: Hlatky Roman , Furuya Yu , Valadka Alex B. , Gonzalez Jorge , Chacko Ari , Mizutani Yasu , Contant Charles F. , Robertson Claudia S.
Published: May 2009

Object. The purpose of this study was to evaluate the extent and timing of impairment of cerebral pressure autoregulation after severe head injury.

Methods. In a prospective study of 122 patients with severe head trauma (median Glasgow Coma Scale Score 6), dynamic tests of pressure autoregulation were performed every 12 hours during the first 5 days postinjury and daily during the next 5 days. The autoregulatory index ([ARI] normal value 5 ± 1.1) was calculated for each test. The changes in the ARI over time were examined and compared with other physiological variables.

The ARI averaged 2.8 ± 1.9 during the first 12 hours postinjury, and continued to decrease to a nadir of 1.7 ± 1.1 at 36 to 48 hours postinjury. At this nadir, in 87% of the patients the value was less than 2.8. This continued deterioration in the ARI during the first 36 to 48 hours postinjury occurred despite an increase in cerebral blood flow ([CBF], p < 0.05) and in middle cerebral artery blood flow velocity ([BFV], p < 0.001), and could not be explained by changes in cerebral perfusion pressure, end-tidal CO2, or cerebral metabolic rate of O2. A marked decrease in cerebrovascular resistance ([CVR], p < 0.001) accompanied this deterioration in the ARI. Patients with a relatively higher BFV on Day 1 had a lower CVR (p < 0.05) and more impaired pressure autoregulation than those with a lower BFV.

Conclusions. The inability of cerebral vessels to regulate CBF normally may play a role in the vulnerability of the injured brain to secondary ischemic insults. These studies indicate that this vulnerability continues and even increases beyond the first 24 hours postinjury. Local factors affecting cerebrovascular tone may be responsible for these findings.