bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiosurgery of vestibular schwannomas: summary of experience in 829 cases
Authors: Lunsford L. Dade , Niranjan Ajay , Flickinger John C. , Maitz Ann , Kondziolka Douglas
Published: May 2009

Object.Management options for vestibular schwannomas (VSs) have greatly expanded since the introduction of stereotactic radiosurgery. Optimal outcomes reflect long-term tumor control, preservation of cranial nerve function, and retention of quality of life. The authors review their 15-year experience.

Methods.Between 1987 and 2002, some 829 patients with VSs underwent gamma knife surgery (GKS). Dose selection, imaging, and dose planning techniques evolved between 1987 and 1992 but thereafter remained stable for 10 years. The average tumor volume was 2.5 cm3. The median margin dose to the tumor was 13 Gy (range 10–20 Gy).

No patient sustained significant perioperative morbidity. The average duration of hospital stay was less than 1 day. Unchanged hearing preservation was possible in 50 to 77% of patients (up to 90% in those with intracanalicular tumors). Facial neuropathy risks were reduced to less than 1%. Trigeminal symptoms were detected in less than 3% of patients whose tumors reached the level of the trigeminal nerve. Tumor control rates at 10 years were 97% (no additional treatment needed).

Conclusions.Superior imaging, multiple isocenter volumetric conformal dose planning, and optimal precision and dose delivery contributed to the long-term success of GKS, including in those patients in whom initial microsurgery had failed. Gamma knife surgery provides a low risk, minimally invasive treatment option for patients with newly diagnosed or residual VS. Cranial nerve preservation and quality of life maintenance are possible in long-term follow up.
The long-term results of gamma knife radiosurgery for hemangioblastomas of the brain
Authors: Wang En-Min , Pan Li , Wang Bing-Jiang , Zhang Nan , Zhou Liang-Fu , Dong Ya-Fei , Dai Jia-Zhong , Cai Pei-Wu , Chen Hong
Published: May 2009

Object. The authors assessed the long-term result of gamma knife surgery (GKS) for hemangioblastomas of the brain (HABs) and show histopathological findings after GKS.

Methods. Thirty-five patients, 28 men and seven women, with a mean age of 36 years underwent GKS. Eighteen patients presented with multiple tumors and 17 with a solitary tumor. Twenty-one patients had von Hippel—Lindau (VHL) disease. The mean tumor diameter was 13 mm (range 5–55 mm). The mean follow up after GKS was 66 months (range 24–114 months). The mean prescription dose was 17.2 Gy (range 12–24 Gy) at the tumor margin. For tumors close to or within the brainstem a prescription dose of 12 to 13 Gy was used.

At the most recent follow up, 29 patients were alive, six were dead, and satisfactory tumor control had been achieved in 29. A stable or improved neurological status was obtained in 21 patients. Eight patients underwent open surgery because of tumor-associated cyst enlargement or the development of new tumors after GKS. Seven patients developed new tumors and five of them required a second GKS. The 1-year tumor control rate was 94%; 2 years, 85%; 3 years, 82%; 4 years, 79%; and 5 years, 71%. Histopathology showed that no tumor cells were found and there was degeneration and necrosis in a tumor nodule 48 months after GKS with a prescription dose of 18 Gy.

Conclusions. Gamma knife surgery was a useful choice for small- or medium-sized, solid HAB in the long term, especially when the tumor margin dose was 18 Gy. Although GKS can treat multiple tumors in a single session, for HABs associated with VHL disease, GKS faces the dual problems of tumor recurrence or development of a new tumor.
Tolerance dose in gamma knife surgery of lesions extending to the anterior visual pathway
Authors: Kenai Hiroyuki , Yamashita Masanori , Nakamura Takaharu , Asano Tomoshige , Sainoh Michifumi , Nagatomi Hirofumi
Published: May 2009

Object.The authors performed a retrospective analysis of the radiation dose to the anterior visual pathway (AVP) to assess its tolerance to gamma knife surgery.

Methods.They examined five cases followed for more than 3 years. The AVP was treated with 10-Gy doses or higher.

The mean maximum delivered dose to the AVP was 14 Gy. Ten gray or more was delivered to 25.5% of the ipsilateral AVP, 12 Gy or more to 12.5% of the ipsilateral AVP, and 14 Gy or more to 5.7% of the ipsilateral AVP. Although the mean follow-up period was 40.8 months (36–51 months), no cases of visual function deterioration developed.

Conclusions.The tolerance dose of the AVP is considered to be less than 8 to 10 Gy; however, although the delivered dose to the AVP definitely exceeded the tolerance dose in all five cases, no visual disturbance has been identified. Longer follow up is required before any final conclusions may be drawn. Nonetheless, it is suggested that a visual disturbance may be avoided by using careful accurate dose planning even if the dose delivered to the AVP is higher than currently believed to be acceptable.
Microvascular decompression after gamma knife surgery for trigeminal neuralgia: intraoperative findings and treatment outcomes
Authors: Shetter Andrew G. , Zabramski Joseph M. , Speiser Burton L.
Published: May 2009

Object. The authors sought to determine whether the results of trigeminal microvascular decompression (MVD) are influenced by prior gamma knife surgery (GKS).

Methods. Gamma knife surgery is an established procedure for treating medically intractable trigeminal neuralgia but failures do occur. The authors assessed six patients (two men and four women; mean age 52 years) who experienced pain recurrence after GKS and elected to undergo trigeminal MVD via retrosigmoid craniotomy. Three patients underwent a single GKS to a maximal dose of 80 Gy, whereas three others underwent a second GKS to total of 120 to 135 Gy.

At surgery, none of the six patients demonstrated excess arachnoid thickening, grossly apparent changes in the nerve itself, or any other tissue alterations that made successful mobilization of a blood vessel from the trigeminal root entry zone technically more difficult. A single individual had a small atherosclerotic plaque in the superior cerebellar artery near its contact point with the trigeminal nerve. Follow up at a mean of 25.4 months (range 7.5–42 months) indicated that five patients were pain free. One patient had improved but still relied on medications for pain control.

Conclusions. In the authors' experience, trigeminal MVD can be performed without added difficulty in patients who have previously undergone GKS. The success rates seem similar to those normally associated with MVD. Patients who elect the less invasive option of GKS can be assured that trigeminal MVD remains a viable alternative at a later date if further surgery is required.
Diagnostic value of thallium-201 chloride single-photon emission computerized tomography in differentiating tumor recurrence from radiation injury after gamma knife surgery for metastatic brain tumors
Authors: Serizawa Toru , Saeki Naokatsu , Higuchi Yoshinori , Ono Junichi , Matsuda Shinji , Sato Makoto , Yanagisawa Masamichi , Iuchi Toshihiko , Nagano Osamu , Yamaura Akira
Published: May 2009

Object.The authors assessed the diagnostic value of201Tl Cl single-photon emission computerized tomography (SPECT), performed after gamma knife surgery (GKS) for metastatic brain tumors in differentiating tumor recurrence from radiation injury.

Methods.Of 6503 metastatic brain tumors treated with GKS,201Tl SPECT was required in 72 to differentiate between tumor recurrence and radiation injury. When the Tl index was greater than 5, the lesion was diagnosed as a tumor recurrence. When the index was < 3.0 it was called radiation injury. In cases with a Tl index between 3 and 5,201Tl SPECT was repeated once per month until the Tl index was greater than 5 or less than 3. If the Tl index fluctuated between 3 and 5 for 2 months, the lesion was diagnosed as radiation injury. The final diagnosis was based on histological examination or clinical course.

The sensitivity of the method was 91%; thus201Tl SPECT is effective for differentiating between tumor recurrence and radiation injury in metastatic brain tumors treated with GKS. Caution is necessary, however, for the following reasons: 1) simple interinstitutional comparisons of Tl indices are not possible because measurement methods are institute specific; 2) steroid administration decreases the Tl index to a variable degree; and 3) a severe radiation injury lesion, as is often seen after repeated GKS or very high dose GKS, may have a Tl index greater than 5.

Conclusions.Used with critical insight201Tl Cl SPECT can be useful in distinguishing between tumor regrowth and radiation necrosis in patients with cerebral metastases.
Racial differences in demographics, acute complications, and outcomes in patients with subarachnoid hemorrhage: a large patient series
Authors: Rosen David , Novakovic Roberta , Goldenberg Fernando D. , Huo Dezheng , Baldwin Maria E. , Frank Jeffrey I. , Rosengart Axel J. , Macdonald R. Loch
Published: May 2009

Object

Few studies have focused on the impact of racial differences in demographics, clinical characteristics, acute complications, and outcomes of patients with aneurysmal subarachnoid hemorrhage (SAH). The purpose of this study was to examine this issue.

Methods

The authors evaluated prospectively collected data on 1711 adult patients with aneurysmal SAH who were entered into two randomized, double-blind, placebo-controlled trials conducted at neurosurgical centers in North America between 1991 and 1997. Admission characteristics, treatment modalities, in-hospital complications, and 3-month outcomes assessed by application of the Glasgow Outcome Scale were compared using the chi-square test, a t-test, the Wilcoxon rank-sum test, and multiple logistic regressions based on a significance level of 0.05 in 241 African-American, 1342 Caucasian, and 128 other racial minority patients.

Caucasian patients were significantly older than patients of other races (p < 0.0001). African-American patients more frequently had a history of hypertension (p < 0.0001) and an elevated blood pressure at the time of admission (p < 0.0001). African-Americans and other racial minorities were more likely to have internal carotid artery aneurysms and Caucasians were more likely to have posterior circulation aneurysms (p = 0.0002). Rates of in-hospital complications were not significantly different except that pulmonary edema occurred more commonly in Caucasians (p = 0.036). After an adjustment was made for significant admission characteristics, the 3-month outcome was not significantly different among the races.

Conclusions

Race was not found to be a prognostic factor for outcome after aneurysmal SAH. The higher SAH mortality rate previously observed in African-American patients is likely a result of a higher incidence of SAH in this group. These findings highlight the importance of primary prevention programs aimed at modifying risk factors for SAH.
Estrogen therapy for experimental intracerebral hemorrhage in rats
Authors: Nakamura Takehiro , Hua Ya , Keep Richard F. , Park Jung-Weon , Xi Guohua , Hoff Julian T.
Published: May 2009

Object

The aims of this study were to determine the following: whether there are sex differences in intracerebral hemorrhage (ICH) induced brain injury in rats, whether delayed administration of 17β-estradiol can reduce ICH-induced brain damage, and whether these effects are estrogen receptor (ER)-dependent.

Methods

Male and female Sprague—Dawley rats received an infusion of 100 µl autologous whole blood into the right basal ganglia. Twenty-four hours later the rats were killed. The effects of 17β-estradiol on ICH-induced brain injury were examined by measuring brain edema and neurological deficits. Both ER-α and hemeoxygenase (HO)-1 were investigated through Western blot and immunohistochemical analysis.

Brain edema was significantly less severe in female compared with that in male rats. The ER antagonist ICI 182,780 exacerbated ICH-induced brain edema in female but not in male rats, indicating that ER-α activation during ICH is protective in female rats. Administration of exogenous 17β-estradiol in male, but not in female, rats significantly attenuated brain edema, neurological deficits, and ICH-induced changes in HO-1 when given 2 hours after hemorrhage. The effects of exogenous 17β-estradiol occurred through an ER-independent mechanism.

Conclusions

Results in this study indicate that 17β-estradiol could be a potential therapeutic agent for ICH.
Long-term benefits in quality of life provided by bilateral subthalamic stimulation in patients with Parkinson disease
Authors: Lyons Kelly E. , Pahwa Rajesh
Published: May 2009

Object. The goals of this study were to evaluate long-term benefits in quality of life in patients with Parkinson disease (PD) after bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) and to evaluate the relationship between improvements in motor function and quality of life.

Methods. Seventy-one patients who received bilateral STN stimulation implants and participated in follow-up review for at least 12 months were included in the study. Fifty-nine patients participated in a 12-month follow-up review and 43 patients in a follow-up review lasting at least 24 months. Patients' symptoms were assessed preoperatively by using the Unified PD Rating Scale (UPDRS) in the “medication-on” and “medication-off” conditions and quality of life was examined using the 39-item PD Questionnaire (PDQ-39). Patient evaluations were repeated postoperatively during periods of stimulation.

The UPDRS activities of daily living (ADL) and motor scores as well as the PDQ-39 total, mobility, ADL, emotional well-being, stigma, and bodily discomfort scores were significantly improved at 12 months compared with baseline scores; the UPDRS ADL and motor scores as well as the PDQ-39 total, mobility, ADL, stigma, and bodily discomfort scores were significantly improved at the longest follow-up examination compared with baseline scores. There was a strong correlation between UPDRS motor and ADL scores and the PDQ-39 total, mobility, and ADL scores. Further analyses indicated that improvements in tremor were only correlated with PDQ-39 ADL subscale scores and rigidity was not correlated with any aspect of quality of life. Nevertheless, bradykinesia was strongly correlated with improvements in the PDQ-39 total, mobility, and ADL scores.

Conclusions. Improvements in quality of life following bilateral DBS of the STN are maintained in the long term. These improvements are strongly correlated with improvements in motor function, primarily with regard to bradykinesia.
Discordance between functional magnetic resonance imaging during silent speech tasks and intraoperative speech arrest
Authors: Petrovich Nicole , Holodny Andrei I. , Tabar Viviane , Correa Denise D. , Hirsch Joy , Gutin Philip H. , Brennan Cameron W.
Published: May 2009

Object. The goal of this study was to investigate discordance between the location of speech arrest during awake cortical mapping, a common intraoperative indicator of hemispheric dominance, and silent speech functional magnetic resonance (fMR) imaging maps of frontal language function.

Methods. Twenty-one cases were reviewed retrospectively. Images of silent speech fMR imaging activation were coregistered to anatomical MR images obtained for neuronavigation. These were compared with the intraoperative cortical photographs and the behavioral results of electrocorticography during awake craniotomy. An fMR imaging control study of three healthy volunteers was then conducted to characterize the differences between silent and vocalized speech fMR imaging protocols used for neurosurgical planning.

Conclusions. Results of fMR imaging showed consistent and predominant activation of the inferior frontal gyrus (IFG) during silent speech tasks. During intraoperative mapping, however, 16 patients arrested in the precentral gyrus (PRG), well posterior to the fMR imaging activity. Of those 16, 14 arrested only in the PRG and not in the IFG as silent speech fMR imaging predicted. The control fMR imaging study showed that vocalized speech fMR imaging shifts the location of the fMR imaging prediction to include the motor strip and may be more appropriate for neurosurgical planning.
Microsurgical robotic system for the deep surgical field: development of a prototype and feasibility studies in animal and cadaveric models
Authors: Morita Akio , Sora Shigeo , Mitsuishi Mamoru , Warisawa Shinichi , Suruman Katopo , Asai Daisuke , Arata Junpei , Baba Shoichi , Takahashi Hidechika , Mochizuki Ryo , Kirino Takaaki
Published: May 2009

Object. To enhance the surgeon's dexterity and maneuverability in the deep surgical field, the authors developed a master—slave microsurgical robotic system. This concept and the results of preliminary experiments are reported in this paper.

Methods. The system has a master control unit, which conveys motion commands in six degrees of freedom (X, Y, and Z directions; rotation; tip flexion; and grasping) to two arms. The slave manipulator has a hanging base with an additional six degrees of freedom; it holds a motorized operating unit with two manipulators (5 mm in diameter, 18 cm in length). The accuracy of the prototype in both shallow and deep surgical fields was compared with routine freehand microsurgery. Closure of a partial arteriotomy and complete end-to-end anastomosis of the carotid artery (CA) in the deep operative field were performed in 20 Wistar rats. Three routine surgical procedures were also performed in cadavers.

The accuracy of pointing with the nondominant hand in the deep surgical field was significantly improved through the use of robotics. The authors successfully closed the partial arteriotomy and completely anastomosed the rat CAs in the deep surgical field. The time needed for stitching was significantly shortened over the course of the first 10 rat experiments. The robotic instruments also moved satisfactorily in cadavers, but the manipulators still need to be smaller to fit into the narrow intracranial space.

Conclusions. Computer-controlled surgical manipulation will be an important tool for neurosurgery, and preliminary experiments involving this robotic system demonstrate its promising maneuverability.
Abolition of spindle oscillations and 3-Hz absence seizurelike activity in the thalamus by using high-frequency stimulation: potential mechanism of action
Authors: Lee Kendall H. , Hitti Frederick L. , Shalinsky Mark H. , Kim Uhnoh , Leiter James C. , Roberts David W.
Published: May 2009

Object

The mechanism of action whereby high-frequency stimulation (HFS) in the thalamus ameliorates tremor and epilepsy is unknown. The authors studied the effects of HFS on thalamocortical relay neurons in a ferret in vitro slice preparation to test the hypothesis that HFS abolishes synchronized oscillations by neurotransmitter release.

Methods

Intracellular and extracellular electrophysiological recordings were made in thalamic slices. The neurons in the thalamic slice spontaneously generated spindle oscillations, and treatment with picrotoxin, a γ-aminobutyric acid A receptor antagonist, resulted in 3- to 4-Hz absence seizurelike activity. High-frequency stimulation (stimulation parameters: 10–1000-µA amplitude; 100-µsec pulse width; 100-Hz frequency; 1–60 seconds) was applied using a concentric bipolar stimulating electrode placed adjacent to the recording electrodes.

High-frequency stimulation within the thalamus generated inhibitory and excitatory postsynaptic potentials, membrane depolarization, an increase in action potential firing during the stimulation period, and abolished the spindle oscillations in the thalamocortical relay neurons. High-frequency stimulation applied to 20-µM picrotoxin-treated slices eliminated the 3- to 4-Hz absence seizurelike activity.

Conclusions

High-frequency stimulation eliminates spontaneous spindle oscillations and picrotoxin-induced absence seizurelike activity in thalamic slices by synaptic neurotransmitter release; thus, HFS may abolish synchronous oscillatory activities such as those that generate tremor and seizures. Paradoxically, HFS, which is excitatory, and surgical lesions of the ventrointermedius thalamus, which are presumably inhibitory, both suppress tremors. This paradox is resolved by recognizing that HFS-mediated neurotransmitter release and thalamic surgery both disrupt the circuit generating tremor or seizure, albeit by different mechanisms.
Cerebral acid—base homeostasis after severe traumatic brain injury
Authors: Clausen Tobias , Khaldi Ahmad , Zauner Alois , Reinert Michael , Doppenberg Egon , Menzel Matthias , Soukup Jens , Alves Oscar Luis , Bullock M. Ross
Published: May 2009

Object. Brain tissue acidosis is known to mediate neuronal death. Therefore the authors measured the main parameters of cerebral acid—base homeostasis, as well as their interrelations, shortly after severe traumatic brain injury (TBI) in humans.

Methods. Brain tissue pH, PCO2, PO2, and/or lactate were measured in 151 patients with severe head injuries, by using a Neurotrend sensor and/or a microdialysis probe. Monitoring was started as soon as possible after the injury and continued for up to 4 days.

During the 1st day following the trauma, the brain tissue pH was significantly lower, compared with later time points, in patients who died or remained in a persistent vegetative state. Six hours after the injury, brain tissue PCO2 was significantly higher in patients with a poor outcome compared with patients with a good outcome. Furthermore, significant elevations in cerebral concentrations of lactate were found during the 1st day after the injury, compared with later time points. These increases in lactate were typically more pronounced in patients with a poor outcome. Similar biochemical changes were observed during later hypoxic events.

Conclusions. Severe human TBI profoundly disturbs cerebral acid—base homeostasis. The observed pH changes persist for the first 24 hours after the trauma. Brain tissue acidosis is associated with increased tissue PCO2 and lactate concentration; these pathobiochemical changes are more severe in patients who remain in a persistent vegetative state or die. Furthermore, increased brain tissue PCO2 (> 60 mm Hg) appears to be a useful clinical indicator of critical cerebral ischemia, especially when accompanied by increased lactate concentrations.
Surgical interventions for traumatic lesions of the brachial plexus: a retrospective study of 134 cases
Authors: Kandenwein Julia A. , Kretschmer Thomas , Engelhardt Martin , Richter Hans-Peter , Antoniadis Gregor
Published: May 2009

Object.Surgical therapy for traumatic brachial plexus lesions is still a great challenge in the field of peripheral nerve surgery. The aim of this study was to present the results of different surgical interventions in patients with this lesion type.

Methods.One hundred thirty-four patients with traumatic brachial plexus lesions underwent surgery between January 1991 and September 1999. In more than 50% of the patients, injury was caused by a motorbike accident. Patients underwent surgery a mean of 6.3 months posttrauma. The following surgical techniques were applied: neurolysis for nerve lesions in continuity (27 cases), grafting for lesions in discontinuity (149 cases), and neurotization for root avulsions (67 cases). Sixty-five patients were evaluated for at least 30 months (mean follow up 42.1 months) after surgery.

Function was graded using the Louisiana State University Health Sciences Center classification system. Only 2% of the patients had Grade 3 or better function preoperatively, increasing to 52% postoperatively. The effect of surgical measures on the functional results for different muscles were compared (supra- or infraspinatus, deltoid, biceps, and triceps muscles); the best results were obtained for biceps muscle function (57% of patients with Medical Research Council Grades M3–M5 function). Graft reconstruction yielded a better outcome than neurotization. Surgery within 5 months posttrauma clearly resulted in improved recovery of motor function compared with later interventions. Sural nerve grafts (monofascicular nerves) showed better results.

Conclusions.The results of neurosurgical interventions for brachial plexus lesions are satisfactory, especially when the operation is performed between 3 and 6 months after trauma.
Missile-induced complete lesions of the tibial nerve and tibial division of the sciatic nerve: results of 119 repairs
Authors: Roganović Zoran , Pavlićević Goran , Petković Stevan
Published: May 2009

Object.Very few extensive studies regarding the repair of missile-induced tibial nerve or tibial division complete lesions have been published to date. In this prospective study, the outcomes of such repairs as well as factors influencing them are presented.

Methods.Between 1991 and 1994, 119 patients with missile-induced complete lesions of the tibial nerve or tibial division were treated in the neurosurgical department of the Military Medical Academy, Belgrade. After at least 4 years of follow up, the final outcome was defined as poor, insufficient, good, or excellent, based on sensorimotor recovery, electromyoneurography-demonstrated recovery, and patient judgment. Good and excellent outcomes were considered to be successful. The influence of the repair level, length of the defect, and preoperative interval on final outcome was also tested.

A successful outcome was obtained in 30.3% of high-level, 50% of intermediate-level, and 85.7% of low-level repairs (p < 0.001). On average, the nerve defect and preoperative interval were significantly shorter in patients with a successful outcome. Significant worsening of the outcome was related to a nerve defect longer than 5 cm and a preoperative interval longer than 4 months. Repair level, preoperative interval, and length of the defect were independent predictors of a successful outcome.

Conclusions.A successful outcome is most probable following the low-level repairs, within the first 4 months after injury, and using grafts shorter than 5 cm. Other repairs can also be beneficial in preventing dangerous anesthesia of the sole of the foot and enabling almost normal walking.
Limitations of three-dimensional reconstructed computerized tomography angiography after clip placement for intracranial aneurysms
Authors: Sagara Yoshiko , Kiyosue Hiro , Hori Yuzo , Sainoo Michifumi , Nagatomi Hirofumi , Mori Hiromu
Published: May 2009

Object. The authors compared the usefulness of three-dimensional (3D) reconstructed computerized tomography (CT) angiography with 3D digital subtraction (DS) angiography in assessing intracranial aneurysms after clip placement. A retrospective review of clinical cases was performed.

Methods. Between May 2001 and May 2003, 17 patients with a total of 20 intracranial aneurysms underwent 3D CT and 3D DS angiography following clip placement. The authors assessed the presence or absence of residual aneurysm necks and stenoocclusive changes in the parent artery and the neighboring artery. The efficacy of CT angiographic visualization was also evaluated.

In 12 of the 20 aneurysms, both 3D modalities similarly demonstrated the residual aneurysm neck and stenoocclusive changes in the parent artery and neighboring artery. Three-dimensional CT angiography failed to demonstrate three of the aneurysms, and the studies were not considered suitable for evaluation because of the presence of metallic artifacts. In the remaining five studies, the 3D CT angiograms did not effectively demonstrate the neighboring and parent arteries. The detectability of residual aneurysm necks was correlated with the clip material and with the number of clips applied.

Conclusions. Three-dimensional DS angiography is still necessary in cases involving multiple clips or with cobalt alloy clips because the clips appear as metal artifacts on 3D CT angiography.
Effect of atorvastatin on spatial memory, neuronal survival, and vascular density in female rats after traumatic brain injury
Authors: Qu Changsheng , Lu Dunyue , Goussev Anton , Schallert Timothy , Mahmood Asim , Chopp Michael
Published: May 2009

Object. Atorvastatin administered after traumatic brain injury (TBI) induced by controlled cortical impact promotes functional improvement in male rats. Note, however, that parallel studies have not been performed in female rats. Therefore, the authors tested the effect of atorvastatin on TBI in female rats.

Methods. Atorvastatin (1 mg/kg/day) was orally administered for 7 consecutive days in female Wistar rats starting 1 day after TBI; control animals received saline. Modified neurological severity scores, the corner turn test, and the Morris water maze test were used to evaluate functional response to treatment. Rats were killed on Day 15 post-TBI, and brain tissue samples were processed for immunohistochemical staining. Atorvastatin administration after brain injury significantly promoted the restoration of spatial memory but did not reduce sensorimotor functional deficits. Treatment of TBI with atorvastatin increased neuronal survival in the CA3 region and the lesion boundary zone and prevented the loss of neuronal processes of damaged neurons in the hippocampal CA3 region but not in the lesion boundary zone on Day 15 after TBI. The protective effect of atorvastatin on the injured neurons perhaps is mediated by increasing the density of vessels in the lesion boundary zone and the hippocampus after TBI.

Conclusions. These data indicate that atorvastatin is beneficial in the treatment of TBI in female rats, although the effect may differ between sexes.
Secondary ischemia impairing the restoration of ion homeostasis following traumatic brain injury
Authors: Stiefel Michael F. , Tomita Yoshiyuki , Marmarou Anthony
Published: May 2009

Object. It is well established that posttraumatic secondary ischemia contributes to poor outcome. Ion dysfunction leading to cytotoxic edema is a primary force in the formation of ischemic brain edema and is a principal component of traumatic brain swelling. Because cell swelling is the result of net ion and water movement, it is crucial to have a thorough understanding of these transient phenomena. The purpose of this study was to characterize the effects of secondary ischemia following traumatic brain injury (TBI) on the ability to restore ion homeostasis.

Methods. Twenty-four Sprague—Dawley rats were divided into four groups of six animals each. The rats underwent transient forebrain ischemia via bilateral carotid artery occlusion combined with hypotension: 15 minutes of forebrain ischemia (Group 1); 60 minutes of forebrain ischemia (Group 2); impact acceleration/TBI (Group 3); and impact acceleration/TBI followed by 15 minutes of ischemia (Group 4).

Ischemia resulted in a rapid accumulation of [K+]e: 41.94 ± 13.65 and 66.33 ± 6.63 mM, respectively, in Groups 1 and 2, with a concomitant decrease of [Na+]e: 64 ± 18 mM and 72 ± 11 mM in Groups 1 and 2. Traumatic brain injury resulted in a less severe although identical trend in ion dysfunction ([K+]e 30.42 ± 11.67 mM and [Na+]e 63 ± 33 mM). Secondary ischemia resulted in prolonged and sustained ion dysfunction with a concomitant elevation of intracranial pressure (ICP).

Conclusions. Analysis of these results indicates that ischemia and TBI are sublethal in isolation; however, when TBI is associated with secondary ischemia, ion dysfunction is sustained and is associated with elevated ICP.
Acute obstructive hydrocephalus associated with infratentorial subdural hygromas complicating Chiari malformation Type I decompression
Authors: Marshman Laurence A. G. , Benjamin Jonathan C. , Chawda Sanjiv J. , David Karoly M.
Published: May 2009

✓ Obstructive hydrocephalus complicating foramen magnum decompression (FMD) for a Chiari malformation (CM) Type I is rare. Two female patients (17 and 55 years old) presented with strain-related headaches. In both cases magnetic resonance (MR) imaging studies confirmed a CM Type I, which was accompanied by syringomyelia in one case. Both patients underwent uncomplicated FMD with good initial recovery. Unfortunately, conditions in both patients deteriorated, with severe headaches occurring between Days 5 and 6 post-FMD. Decreased consciousness occurred in one case. In both patients, computerized tomography scanning demonstrated an acute obstructive hydrocephalus associated with bilateral infratentorial extraaxial fluid collections (EAFCs). In addition, left parafalcine and convexity EAFCs were present in one case. An emergency external ventricular drain was required in one patient, with delayed conversion to a ventriculoperitoneal shunt. Spontaneous resolution occurred in the other patient without neurosurgical intervention. In both cases, MR imaging confirmed that each EAFC was subdural, resembled cerebrospinal fluid (CSF), and had distorted the superior cerebellum anteroinferiorly. Despite upper fourth ventricle/aqueduct compromise in one case, normal aqueduct flow artifacts were apparent on examination. All EAFCs resolved spontaneously.

Obstructive hydrocephalus complicating FMD is rare but invariably associated with infratentorial EAFCs, which were confirmed to be subdural hygromas in this report. The authors assert that hydrocephalus results from upper fourth ventricle/aqueduct compromise as a result of CSF subdural dissection following a pinhole arachnoid tear on durotomy. Because such hygromas spontaneously resolve, permanent shunt insertion should be avoided.
Transvenous embolization for a purely intraorbital arteriovenous fistula
Authors: Deguchi Jun , Yamada Makoto , Ogawa Ryusuke , Kuroiwa Toshihiko
Published: May 2009

✓ Purely intraorbital arteriovenous fistulas (AVFs) are rare, and their clinical management is controversial. The authors successfully treated a patient with an intraorbital AVF by transvenous embolization alone. An accurate distinction between an arteriovenous malformation (AVM), which is characterized by the existence of a nidus, and an AVF, which has no nidus, is important and requires superselective ophthalmic artery angiography. Treatment of an intraorbital AVF by transvenous embolization can improve visual function.
Extended remission of a recurrent median nerve malignant peripheral nerve sheath tumor after multimodal treatment
Authors: Landy Howard , Feun Lynn , Markoe Arnold , Patchen Sherri , Bruce Joy , Marcus Justin , Levi Allan
Published: May 2009

✓ Malignant peripheral nerve sheath tumors (MPNSTs) are difficult to control despite aggressive treatment. In this report the authors describe the treatment and follow-up review of a patient with neurofibromatosis Type 1 who harbored a recurrent median nerve MPNST. The man underwent preoperative intraarterial and intravenous chemotherapy followed by additional surgery for gross-total removal and postoperative radiotherapy. Two courses of preoperative intraarterial cisplatin and intravenous Adriamycin produced significant tumor shrinkage. Gross-total removal of the remaining tumor without amputation of the arm was followed by fractionated radiotherapy (total minimum tumor dose 6485 cGy, maximal dose 6575 cGy). The patient is alive 9.5 years after treatment without evidence of tumor recurrence and with only focal median nerve functional deficits. A review of the patient's treatment is warranted to provide a description of a regimen that may be useful in the treatment of similar patients in the future.
Surgery for primary brain tumors at United States academic training centers: results from the Residency Review Committee for Neurological Surgery
Authors: Jane John A. , Sulton Larry D. , Laws Edward R.
Published: May 2009

Object. Surgery for primary brain tumors has been an important index of the quality of neurosurgical training programs in the US. The scope of such cases and the proportion of surgeries performed transsphenoidally are an interesting means of tracking the effectiveness of residency education.

Methods. Program Information Forms from the 94 American Council for Graduate Medical Education—approved US neurosurgical residency programs were reviewed for the period between 2000 and 2003. Particular attention was focused on an analysis of the cases requiring craniotomy for primary brain tumor and transsphenoidal surgery.

The mean annual number of primary brain tumor cases per program was 195, with a range from 36 to 724 cases. The proportion of primary brain tumors accessed transsphenoidally was 20%. The mean annual number of transsphenoidal operations performed at academic training centers was 39. A wide range in the frequency of transsphenoidal cases from one program to another was also noted. Almost one third of training centers performed fewer than 20 transsphenoidal operations annually and 80% performed fewer than 50.

Conclusions. Most neurosurgical training programs provide residents with excellent experience in craniotomy for primary brain tumors. Practice with transsphenoidal surgery, however, is less well represented and tends to be clustered at several active centers. The implications for neurosurgical education are significant.
Extracranial—intracranial bypass in the treatment of occlusive cerebrovascular disease and intracranial aneurysms in the United States between 1992 and 2001: a population-based study
Authors: Amin-Hanjani Sepideh , Butler William E. , Ogilvy Christopher S. , Carter Bob S. , Barker Fred G.
Published: May 2009

Object. The authors assessed the results of extracranial—intracranial (EC—IC) bypass surgery in the treatment of occlusive cerebrovascular disease and intracranial aneurysms in the US between 1992 and 2001 by using population-based methods.

Methods. This is a retrospective cohort study based on data from the Nationwide Inpatient Sample (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, Rockville, MD). Five hundred fifty-eight operations were performed at 158 hospitals by 115 identified surgeons. The indications for surgery were cerebral ischemia in 74% of the operations (2.4% mortality rate), unruptured aneurysms in 19% of the operations (7.7% mortality rate), and ruptured aneurysms in 7% of the operations (21% mortality rate). Overall, 4.6% of the patients died and 4.7% of the patients were discharged to long-term facilities, 16.4% to short-term facilities, and 74.2% to their homes. The annual number of admissions in the US increased from 190 per year (1992–1996) to 360 per year (1997–2001), whereas the mortality rates increased from 2.8% (1992–1996) to 5.7% (1997–2001).

The median annual number of procedures was three per hospital (range one–27 operations) or two per surgeon (range one–21 operations). For 29% of patients, their bypass procedure was the only one recorded at their particular hospital during that year; for these institutions the mean annual caseload was 0.4 admissions per year. For 42% of patients, their particular surgeon performed no other bypass procedure during that year. Older patient age (p < 0.001) and African-American race (p = 0.005) were risk factors for adverse outcome. In a multivariate analysis in which adjustments were made for age, sex, race, diagnosis, admission type, geographic region, medical comorbidity, and year of surgery, high-volume hospitals less frequently had an adverse discharge disposition (odds ratio 0.54, p = 0.03).

Conclusions. Most EC—IC bypasses performed in the US during the last decade were performed for occlusive cerebrovascular disease. Community mortality rates for aneurysm treatment including bypass procedures currently exceed published values from specialized centers and, during the period under study, the mortality rates increased with time for all diagnostic subgroups. This technically demanding procedure has become a very low-volume operation at most US centers.
Reduced mortality rate in patients with severe traumatic brain injury treated with brain tissue oxygen monitoring
Authors: Stiefel Michael F. , Spiotta Alejandro , Gracias Vincent H. , Garuffe Alicia M. , Guillamondegui Oscar , Maloney-Wilensky Eileen , Bloom Stephanie , Grady M. Sean , LeRoux Peter D.
Published: May 2009

Object. An intracranial pressure (ICP) monitor, from which cerebral perfusion pressure (CPP) is estimated, is recommended in the care of severe traumatic brain injury (TBI). Nevertheless, optimal ICP and CPP management may not always prevent cerebral ischemia, which adversely influences patient outcome. The authors therefore determined whether the addition of a brain tissue oxygen tension (PO2) monitor in the treatment of TBI was associated with an improved patient outcome.

Methods. Patients with severe TBI (Glasgow Coma Scale [GCS] score < 8) who had been admitted to a Level I trauma center were evaluated as part of a prospective observational database. Patients treated with ICP and brain tissue PO2 monitoring were compared with historical controls matched for age, pathological features, admission GCS score, and Injury Severity Score who had undergone ICP monitoring alone. Therapy in both patient groups was aimed at maintaining an ICP less than 20 mm Hg and a CPP greater than 60 mm Hg. Among patients whose brain tissue PO2 was monitored, oxygenation was maintained at levels greater than 25 mm Hg. Twenty-five patients with a mean age of 44 ± 14 years were treated using an ICP monitor alone. Twenty-eight patients with a mean age of 38 ± 18 years underwent brain tissue PO2-directed care. The mean daily ICP and CPP levels were similar in each group. The mortality rate in patients treated using conventional ICP and CPP management was 44%. Patients who also underwent brain tissue PO2 monitoring had a significantly reduced mortality rate of 25% (p < 0.05).

Conclusions. The use of both ICP and brain tissue PO2 monitors and therapy directed at brain tissue PO2 is associated with reduced patient death following severe TBI.
Surgical management of adrenocorticotropic hormone—secreting macroadenomas: outcome and challenges in patients with Cushing's disease or Nelson's syndrome
Authors: De Tommasi Claudio , Vance Mary Lee , Okonkwo David O. , Diallo Alfa , Laws Edward R.
Published: May 2009

Object. Adrenocorticotropic hormone (ACTH)—secreting pituitary macroadenomas are an uncommon cause of Cushing's disease (CD) and, subsequently, Nelson's syndrome (NS). They have been associated with low postoperative remission rates. The outcome of modern surgical treatment is unclear and thus was assessed in a series of 43 patients, with the goal of improving therapeutic results in patients with ACTH-secreting macroadenomas.

Methods. Thirty-seven patients presented with CD and six with NS. They represented 15% of the patients surgically treated at the authors' institution for ACTH-secreting adenomas. The median patient age was 38 years (range 14–71 years), and the mean duration of follow up was 37 months (range 1–108 months).

Remission occurred in 25 (67.6%) of 37 patients with CD, whereas the disease persisted in 12 (32.4%) of 37 patients. After an initial remission, three (12%) of 25 patients demonstrated signs and symptoms indicative of disease recurrence. Among patients with NS, only one (16.6%) displayed remission. Invasion of the dura mater by tumor was histologically demonstrated in 10 patients with CD and in two patients with NS.

Conclusions. Comprehensive management of CD caused by ACTH-secreting macroadenomas through the appropriate use of combination therapy, including surgery, radiotherapy, radiosurgery, and adrenalectomy, can lead to outcomes similar to those for microadenomas. Disease recurrence and persistence rates are higher, often because of the invasiveness associated with macroadenomas. Remission of NS-associated macroadenomas is difficult to achieve. Strategies for the characterization and treatment of invasive macroadenomas are needed.
Rathke cleft cyst intracystic nodule: a characteristic magnetic resonance imaging finding
Authors: Binning Mandy J. , Gottfried Oren N. , Osborn Anne G. , Couldwell William T.
Published: May 2009

Object. The fluid content of Rathke cleft cysts (RCCs) displays variable appearances on magnetic resonance (MR) images and can appear indistinguishable from other intrasellar or suprasellar cystic lesions. Intracystic nodules associated with individual RCCs have been noted, but to date their significance has not been fully explored.

Methods. The authors retrospectively reviewed MR imaging studies obtained in patients harboring intrasellar or suprasellar lesions that were consistent with RCCs to identify the presence and imaging characteristics of intracystic nodules.

An intracystic nodule was present in nine (45%) of 20 patients with an RCC. All intracystic nodules were clearly visible and displayed a characteristic low signal intensity on T2-weighted MR images. The nodule was only visualized on T1-weighted images in four cases, in which it exhibited a consistent high signal intensity similar to that of the cyst fluid. The nodules did not enhance following the intravenous administration of a contrast agent.

Conclusions. Although it is difficult to differentiate RCCs from other sellar cystic lesions because of the variable signal intensities displayed on MR images, the intensity of the intracystic nodule seems consistent on T1- and T2-weighted images, and the nodule is always clearly visible on T2-weighted images. With a nonenhancing cystic lesion that does not cause significant symptoms in the patient, the identification of an intracystic nodule with a characteristic signal intensity will aid in the diagnosis of RCC and the selection of conservative management.
Enhanced brain angiogenesis in chronic cerebral hypoperfusion after administration of plasmid human vascular endothelial growth factor in combination with indirect vasoreconstructive surgery
Authors: Kusaka Noboru , Sugiu Kenji , Tokunaga Koji , Katsumata Atsushi , Nishida Ayumi , Namba Katsunari , Hamada Hirofumi , Nakashima Hiroyuki , Date Isao
Published: May 2009

Object. Vascular endothelial growth factor (VEGF) is a secreted mitogen associated with angiogenesis. The conceptual basis for therapeutic angiogenesis after plasmid human VEGF gene (phVEGF) transfer has been established in patients presenting with limb ischemia and myocardial infarction. The authors hypothesized that overexpression of VEGF using a gene transfer method combined with indirect vasoreconstruction might induce effective brain angiogenesis in chronic cerebral hypoperfusion, leading to prevention of ischemic attacks.

Methods. A chronic cerebral hypoperfusion model induced by permanent ligation of both common carotid arteries in rats was used in this investigation. Seven days after induction of cerebral hypoperfusion, encephalomyosynangiosis (EMS) and phVEGF administration in the temporal muscle were performed. Fourteen days after treatment, the VEGF gene therapy group displayed numbers and areas of capillary vessels in temporal muscles that were 2.2 and 2.5 times greater, respectively, in comparison with the control group. In the brain, the number and area of capillary vessels in the group treated with the VEGF gene were 1.5 and 1.8 times greater, respectively, relative to the control group.

Conclusions. In rat models of chronic cerebral hypoperfusion, administration of phVEGF combined with indirect vasoreconstructive surgery significantly increased capillary density in the brain. The authors' results indicate that administration of phVEGF may be an effective therapy in patients with chronic cerebral hypoperfusion, such as those with moyamoya disease.