bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic resonance angiographic evidence of sex-linked variations in the circle of Willis and the occurrence of cerebral aneurysms
Authors: Horikoshi Toru , Akiyama Iwao , Yamagata Zentaro , Sugita Masao , Nukui Hideaki
Published: May 2009

Object. In this study the authors investigated the relationship between variations in the circle of Willis observed on magnetic resonance (MR) angiograms and locations of cerebral aneurysms, and evaluated the risk of aneurysm formation.

Methods. One hundred thirty-one patients with cerebral aneurysms were retrospectively selected from a series of 4518 patients who underwent MR angiography at one neurosurgical institute. Variations in the anatomy of the circle of Willis were simply classified into Type A, in which there was no visualization of a unilateral A1 segment, and Type P, in which there was a fetal type of posterior cerebral artery that was continuously delineated from the internal carotid artery (ICA) through the posterior communicating artery. All other variations in the circle of Willis were defined as Type O (ordinary type of variations). An additional 440 patients who did not harbor cerebral aneurysms were randomly selected for a comparison.

Anterior communicating artery aneurysms were significantly related to the Type A anatomy and ICA aneurysms to Type P anatomy. Male patients who did not harbor aneurysms tended to have Type A anatomy, whereas women had a significantly greater incidence of Type P.

Conclusions. This sex-linked difference in anatomical variations may be correlated to the well-known sex-linked difference in aneurysm distribution.
Detection and significance of focal, interictal, slow-wave activity visualized by magnetoencephalography for localization of a primary epileptogenic region
Authors: Ishibashi Hideaki , Simos Panagiotis G. , Castillo Eduardo M. , Maggio William W. , Wheless James W. , Kim Howard L. , Venkataraman Vijay , Sanders Daniel K. , Breier Joshua I. , Zhang Wenbo , Davis Robert N. , Papanicolaou Andrew C.
Published: May 2009

Object. Magnetoencephalography (MEG) is a novel noninvasive diagnostic tool used to determine preoperatively the location of the epileptogenic zone in patients with epilepsy. The presence of focal slowing of activity recorded by electroencephalography (EEG) is an additional indicator of an underlying pathological condition in cases of intractable mesial temporal lobe epilepsy (MTLE). In the present study the authors examined the significance of focal, slow-wave and interictal spike activity detected using MEG in 29 patients who suffered from MTLE that was not associated with structural brain lesions.

Methods. All patients underwent resective surgery after MEG and EEG monitoring. Equivalent single-dipole modeling was applied to focal low-frequency magnetic activity (LFMA) and interictal paroxysmal activity. Lateralized LFMA was defined as trains of rhythmic activity over the temporal area, with frequencies lower than 7 Hz, which were easily distinguished from background activity.

Lateralized LFMA was found in 17 patients (58.6%); it always occurred on the side ipsilateral to the side of resection and displayed a maximum amplitude over the temporal area. Dipolar sources of magnetic flux computed during slow-wave trains were found in the majority of cases in the posterior superior temporal region and, occasionally, in mesial temporal structures that were subsequently resected. With respect to lateralization there was never disagreement between LFMA and MEG interictal spike sources. Thus, in patients with MTLE that is not associated with a mass lesion LFMA is topographically related to the epileptogenic area and, therefore, has value for reliable determination of the side and, possibly, the location of this area.

Conclusions. Although focal slowing of EEG background activity is generally considered to be a nonspecific sign of functional disturbance, interictal LFMA in patients with MTLE should be conceptualized as a distinct electrographic phenomenon that is directly related to the epileptogenic abnormality. Analyzing the interictal MEG distribution of LFMA and sharp activity improves the diagnostic utility of MEG in patients with suspected TLE who are undergoing surgical evaluation.
Reversible ischemia around intracerebral hemorrhage: a single-photon emission computerized tomography study
Authors: Siddique M. Shahid , Fernandes Helen M. , Wooldridge Thomas D. , Fenwick John D. , Slomka Piotr , Mendelow A. David
Published: May 2009

Object. A zone of perilesional ischemia has been demonstrated around intracerebral hemorrhage (ICH) in numerous experimental models and in human studies. There is potential for perfusion recovery in the zone of perilesional oligemia around ICH. The authors sought to demonstrate, quantify, and study the chronological evolution of perilesional ischemic change in ICH in humans by measuring cerebral blood flow.

Methods. Eleven patients with spontaneous supratentorial ICH underwent two technetium-99m hexamethylpropyleneamine oxime single-photon emission computerized tomography (SPECT) scanning, one in the acute stage (within days of ictus) and the other in the late stage (6–9 months postictus). All patients in this study were treated nonsurgically. Methods of SPECT data analysis based on count differences in regions of interest can be difficult to apply to images with large space-occupying lesions such as ICH, because of the distortion of intracranial anatomy, midline shift, and alterations in the three-dimensional (3D) characteristics of the lesion over time (that is, absorption of the hematoma on the later studies). The authors used the following method: the late and early images were registered and aligned to a common 3D orientation and were normalized to maximal counts. The late images were then compared voxel by voxel with the early ones. The region-growing algorithm was used to discern the difference between the two images, outlining voxels in the perihematoma region, with a signal improvement of at least 15% on the late image.

Discrete brain regions around the hematoma with at least a 15% improvement in radiotracer uptake (and hence perfusion) in the late images were observed in all cases. The mean volume of brain with a greater than 15% improvement in perfusion between the two studies was 34.8 cm3 (range 7.2–71.3 cm3). These volumes represent regions of the brain that were poorly perfused in the initial studies. This may represent a zone of reversible perilesional oligemia (penumbra) in ICH in humans.

Conclusions. This is the first study in which it is documented that some of the perilesional hypoperfused tissue around human ICH regains its perfusion in the long term, leading the authors to suggest that there may be a penumbra in human ICH. Medical or surgical therapeutic interventions could increase the volume of perilesional brain that recovers after the initial insult. The results of this study therefore support the concept that intervention in ICH has the potential to reduce the ultimate neurological deficit and improve outcome.
Compartments in arteriovenous malformation nidi demonstrated with rotational three-dimensional digital subtraction angiography by using selective microcatheterization
Authors: Kakizawa Yukinari , Nagashima Hisashi , Oya Fusakazu , Ito Kiyoshi , Tanaka Yuichiro , Hongo Kazuhiro , Kobayashi Shigeaki
Published: May 2009

✓ Although in several histological studies of arteriovenous malformation (AVM) nidi the presence of compartments has been documented, no clinical study has been published. The present study was conducted to determine the presence of nidus compartments in clinical cases by using a new radiographic method.

Two patients with unruptured and one with a ruptured AVM (all Spetzler—Martin Grade III) were studied. A microcatheter was superselectively introduced into each of two or three feeding arteries of the AVMs under three-dimensional (3D) angiographic guidance to obtain 3D images of the nidus by using rotational digital subtraction angiography. On 3D images the different feeding arteries were found to be independent from one another, which allowed the authors to confirm the presence of compartments. On the other hand, separate feeding arteries often had a common draining vessel. Compartments in AVM nidi were demonstrated by a novel rotational 3D angiographic procedure by using superselective microcatheterization, which should be useful for designing treatment strategies for large and complex AVMs.
Adult pial arteriovenous fistula and superior sagittal sinus stenosis: angiographic evidence for high-flow venopathy at an atypical location
Authors: Song Joon K. , Patel Aman B. , Duckwiler Gary R. , Gobin Y. Pierre , Jahan Reza , Martin Neil A. , Cacayorin Edwin D. , Viñuela Fernando
Published: May 2009

✓ The authors present the case of a 69-year-old man who suffered from bilateral cortical venous hypertension due to a brain pial arteriovenous malformation (AVM) with a high-flow fistula. The AVM became complicated by the development of a high-grade stenosis of the posterior superior sagittal sinus (SSS). A comparison of cerebral angiograms obtained at different times revealed that the severe SSS stenosis had developed within a 5-year period and was located distal to the nidus of the left parietal AVM nidus, away from the entrance of the dominant superior superficial cortical draining vein into the SSS. The high-flow fistula was occluded with detachable coils and the AVM nidus was further embolized with acrylic. The SSS stenosis was mechanically dilated by means of balloon angioplasty and stent placement. This case provides angiographic evidence to support the hypothesis that a pial arteriovenous fistula in an adult can cause high-flow occlusive venopathy in a major sinus within a relatively short time and that this acquired high-flow occlusive venopathy can develop at an atypical location distant from the nidus of the AVM.
Hearing restoration after resection of an intracanalicular vestibular schwannoma: a role for emergency surgery?
Authors: Meiteles Lawrence Z. , Liu James K. , Couldwell William T.
Published: May 2009

✓ Patients with vestibular schwannomas (VSs) most commonly present with sensorineural hearing loss, which is often insidious or gradual. Up to 26% of patients may present with sudden hearing loss, however, which poses an important surgical challenge. Sudden hearing loss has been attributed to spasm or occlusion of the labyrinthine artery resulting from tumor compression, and it is usually treated with corticosteroids. Hearing preservation surgery is not usually attempted in patients who have poor or nonserviceable hearing preoperatively.

The authors describe a 68-year-old man with complete deafness of the left ear since childhood, who developed sudden, profound sensorineural hearing loss in the right ear. Magnetic resonance imaging revealed a small right-sided intracanalicular tumor. Treatment with high-dose corticosteroids produced only minimal improvement in hearing. Subsequent emergency decompression and resection of a VS resulted in rapid improvement and restoration of hearing, with facial nerve preservation.

Although most neurotologic lesions in patients with hearing in only one ear are managed nonsurgically, resection of small tumors in the setting of sudden hearing loss should be considered in selected cases. This finding indicates that a therapeutic window may exist during which sudden hearing loss caused by intracanalicular tumors is reversible.
Analysis of homozygous deletion of the p16 gene and correlation with survival in patients with glioblastoma multiforme
Authors: Kamiryo Takanori , Tada Kenji , Shiraishi Shoji , Shinojima Naoki , Nakamura Hideo , Kochi Masato , Kuratsu Jun-ichi , Saya Hideyuki , Ushio Yukitaka
Published: May 2009

Object. One of the most frequent genetic abnormalities found in patients with glioblastoma multiforme (GBM) is homozygous deletion of the p16 tumor suppressor gene. The authors investigated whether this deletion is associated with prognosis in patients with GBM.

Methods. In 46 adult patients with supratentorial GBM, homozygous deletion of the p16 gene in tumor DNA was examined using the multiplex polymerase chain reaction assay. The deletion was confirmed in 14 (30.4%) of 46 patients, eight (30.8%) of 26 men and six (30.0%) of 20 women. Cox proportional hazard regression analysis, adjusted for age at surgery, the Karnofsky Performance Scale score, extent of resection, and the MIB-1 labeling index, revealed that homozygous deletion of the p16 gene was significantly associated with overall survival and progression-free survival in men, but not in women.

Conclusions. The results of this study suggest that p16 homozygous deletion is a significant unfavorable prognostic factor in male patients with GBM.
Stereotactic radiosurgery for the treatment of dural arteriovenous fistulas involving the transverse—sigmoid sinus
Authors: Pan David Hung-chi , Chung Wen-yuh , Guo Wan-yuo , Wu Hsiu-mei , Liu Kang-du , Shiau Cheng-ying , Wang Ling-wei
Published: May 2009

Object. The aim of this study was to assess the efficacy and safety of radiosurgery for the treatment of dural arteriovenous fistulas (DAVFs) located in the region of the transverse—sigmoid sinus.

Methods. A series of 20 patients with DAVFs located in the transverse—sigmoid sinus, who were treated with gamma knife surgery between June 1995 and June 2000, was evaluated. According to the Cognard classification, the DAVF was Type I in four patients, Type IIa in seven, Type IIb in two, and combined Type IIa+b in seven. Nine patients had previously been treated with surgery and/or embolization, whereas 11 patients underwent radiosurgery alone. Radiosurgery was performed using multiple-isocenter irradiation of the delineated DAVF nidus. The target volume ranged from 1.7 to 40.7 cm3. The margin dose delivered to the nidus ranged from 16.5 to 19 Gy at a 50 to 70% isodose level.

Nineteen patients were available for follow-up review, the duration of which ranged from 6 to 58 months (median 19 months). Of the 19 patients, 14 (74%) were cured of their symptoms. At follow up, magnetic resonance imaging and/or angiography demonstrated complete obliteration of the DAVF in 11 patients (58%), subtotal obliteration (95% reduction of the nidus) in three (16%), and partial obliteration in another five (26%). There was no neurological complication related to the treatment. One patient experienced a recurrence of the DAVF 18 months after angiographic confirmation of total obliteration, and underwent a second course of radiosurgery.

Conclusions. Stereotactic radiosurgery provides a safe and effective option for the treatment of DAVFs involving the transverse and sigmoid sinuses. For some aggressive DAVFs with extensive retrograde cortical venous drainage, however, a combination of endovascular embolization and surgery may be necessary.
Multicenter study of the feasibility and safety of using the Memotherm carotid arterial stent for extracranial carotid artery stenosis
Authors: Qureshi Adnan I. , Suri M. Fareed K. , New Gishel , Wadsworth Daniel C. , Dulin Joan , Hopkins L. Nelson
Published: May 2009

Object. Carotid artery (CA) angioplasty with stent placement has been proposed as an alternative technique for revascularization in cases of CA stenosis. In this report the authors review the results of a multicenter Phase I study in which they evaluated the safety and feasibility of using a new self-expanding nitinol stent, the Bard Memotherm, to treat CA stenosis.

Methods. Enrollment was limited to patients in whom there was either 50% or greater symptomatic or 70% or greater asymptomatic stenosis of the internal CA. The primary endpoint was a technically successful implantation procedure (delivery of the stent to the target site and retrieval of the delivery device), resulting in less than 30% residual stenosis demonstrated on immediate postprocedure (control) angiograms, and no incidence of mortality, ipsilateral stroke, Q-wave myocardial infarction, or other major cardiovascular events immediately after or within 30 days following the procedure.

Stent placement was attempted for 73 lesions in 71 patients (mean age 71.3 ± 8.5 years), 43 (61%) of whom were men. The mean degree of stenosis was 82.6 ± 9%. The stenosis was symptomatic in 27 (37%) and asymptomatic in 46 (63%) of 73 lesions. In four procedures the stent could not be delivered or released. The mean residual stenosis observed on angiograms was 3.8 ± 6.9% in the 69 lesions treated with the Bard Memotherm stent; residual stenosis was greater than 30% in one of the 69 procedures. The primary endpoint was achieved in 65 (89%) of the 73 procedures. One patient experienced a major ischemic stroke and another patient died of intracerebral hemorrhage. The overall 1-month stroke rate was 2.7% for 73 attempted procedures. One patient died of pneumonia and acute respiratory distress syndrome, which occurred 3 weeks after the stent procedure and was unrelated to the procedure.

Conclusions. The Memotherm stent can be used to treat patients with CA stenosis and is associated with a low periprocedure complication rate. Long-term follow-up studies are underway to determine the impact of stent placement on the risk of ipsilateral ischemic events.
Optimal location of thalamotomy lesions for tremor associated with Parkinson disease: a probabilistic analysis based on postoperative magnetic resonance imaging and an integrated digital atlas
Authors: Atkinson Jeffrey D. , Collins D. Louis , Bertrand Gilles , Peters Terry M. , Pike G. Bruce , Sadikot Abbas F.
Published: May 2009

Object. Renewed interest in stereotactic neurosurgery for movement disorders has led to numerous reports of clinical outcomes associated with different treatment strategies. Nevertheless, there is a paucity of autopsy and imaging data that can be used to describe the optimal size and location of lesions or the location of implantable stimulators. In this study the authors correlated the clinical efficacy of stereotactic thalamotomy for tremor with precise anatomical localization by using postoperative magnetic resonance (MR) imaging and an integrated deformable digital atlas of subcortical structures.

Methods. Thirty-one lesions were created by stereotactic thalamotomy in 25 patients with tremor-dominant Parkinson disease. Lesion volume and configuration were evaluated by reviewing early postoperative MR images and were correlated with excellent, good, or fair tremor outcome categories. To allow valid comparisons of configurations of lesions with respect to cytoarchitectonic thalamic boundaries, the MR image obtained in each patient was nonlinearly deformed into a standardized MR imaging space, which included an integrated atlas of the basal ganglia and thalamus. The volume and precise location of lesions associated with different clinical outcomes were compared using nonparametric statistical methods. Probabilistic maps of lesions in each tremor outcome category were generated and compared.

Statistically significant differences in lesion location between excellent and good, and excellent and fair outcome categories were demonstrated. On average, lesions associated with excellent outcomes involved thalamic areas located more posteriorly than sites affected by lesions in the other two outcome groups. Subtraction analysis revealed that lesions correlated with excellent outcomes necessarily involved the interface of the nucleus ventralis intermedius (Vim; also known as the ventral lateral posterior nucleus [VLp]) and the nucleus ventrocaudalis (Vc; also known as the ventral posterior [VP] nucleus). Differences in lesion volume among outcome groups did not achieve statistical significance.

Conclusions. Anatomical evaluation of lesions within a standardized MR image—atlas integrated reference space is a useful method for determining optimal lesion localization. The results of an analysis of probabilistic maps indicates that optimal relief of tremor is associated with lesions involving the Vim (VLp) and the anterior Vc (VP).
Vertebral artery—posterior inferior cerebellar artery bypass with a superficial temporal artery graft to treat aneurysms involving the posterior inferior cerebellar artery
Authors: Hamada Jun-ichiro , Todaka Tatemi , Yano Shigetoshi , Kai Yutaka , Morioka Motohiro , Ushio Yukitaka
Published: May 2009

Object. In patients with aneurysms that require occlusion of the posterior inferior cerebellar artery (PICA), revascularization of this artery should be performed. A novel surgical method for revascularization of the PICA is presented.

Methods. After a segment of the superficial temporal artery (STA) was harvested, the aneurysm was treated by trapping, followed by placement of a vertebral artery (VA)—PICA bypass in which the STA segment was used as a graft. When the length of the proximal PICA was inadequate, the distal end of the STA was anastomosed to the proximal PICA in an end-to-side fashion. When the length of the proximal PICA was adequate, the STA was anastomosed to the proximal PICA in an end-to-end fashion. In either case, the proximal end of the STA was anastomosed to the VA in an end-to-side fashion. This procedure was used in nine patients whose aneurysms involved the PICA. Although partial lateral medullary syndrome developed in one of them, follow-up evaluation revealed graft patency in all patients. There were no instances of recurrent hemorrhage or ischemia.

Conclusions. Although this procedure requires harvesting of an STA graft and two anastomoses, it facilitates anterograde flow to the PICA territory. It also involves minimal mobilization of brainstem perforating vessels and the proximal PICA.
Perfusion- and diffusion-weighted magnetic resonance imaging for monitoring decompressive craniectomy in animals with experimental hemispheric stroke
Authors: Doerfler Arnd , Engelhorn Tobias , Heiland Sabine , Benner Thomas , Forsting Michael
Published: May 2009

Object. The aim of this study was to use two types of serial magnetic resonance (MR) imaging—perfusionweighted (PW) and diffusion-weighted (DW)—to monitor craniectomy in rats with hemispheric stroke.

Methods. Focal cerebral ischemia was induced in 36 rats by using an endovascular method of occlusion of the middle cerebral artery (MCAO). Craniectomy was performed 4 or 24 hours later in 12 animals each. Twelve control animals underwent occlusion but did not receive treatment. Perfusion-weighted, DW, and T2-weighted MR images were obtained at 4, 24, 48, 72, and 168 hours postocclusion in all animals. Relative regional cerebral blood volumes and apparent diffusion coefficients (ADCs) were calculated for the cortex and basal ganglia. Hemispheric lesion volumes (expressed as percentages of total brain volumes; %HLV) as they appeared on DW and T2-weighted MR images and on histological slices stained with 2,3,5-triphenyltetrazolium chloride were compared. Neurological performances and infarct volumes measured 7 days postocclusion were used as study end points.

Both PW and DW images demonstrated ischemic tissue 4 hours after MCAO in all animals. Early treatment by performing craniectomy significantly improved cortical perfusion (p < 0.01), whereas the same procedure conveyed no benefit to the basal ganglia. Compared with findings in control animals, the DW image—derived %HLV was significantly reduced (p < 0.01) and the cortical ADCs at 4 and 24 hours postocclusion were significantly higher in animals treated early (p < 0.05). Late treatment with craniectomy did not significantly affect cerebral perfusion. The correlation between the DW imaging—derived %HLV and the histologically derived %HLV at 4 to 72 hours postocclusion was good (r = 0.74), whereas at Day 7 postocclusion the %HLV was underestimated up to 41% on DW imaging. At 4 hours postocclusion T2-weighted imaging failed to demonstrate the ischemic lesion, whereas from 24 to 72 hours postocclusion the correlation between the T2-weighted imaging—derived %HLV and the histologically derived %HLV was good (r > 0.81). Neurological performance was significantly improved in animals treated using craniectomy.

Conclusions. Early craniectomy significantly improves cortical perfusion through leptomeningeal collateral vessels, significantly reduces infarct size, and improves neurological performance in animals with experimental acute hemispheric infarction. Both PW and DW imaging are suitable for noninvasive monitoring of the effects of decompressive craniectomy.
Management of tumor bed cysts after chemotherapeutic wafer implantation
Authors: McGirt Matthew J. , Villavicencio Alan T. , Bulsara Ketan R. , Friedman Henry S. , Friedman Allan H.
Published: May 2009

✓ Adjuvant use of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) wafers with surgical resection is becoming common for the treatment of malignant gliomas. Cyst formation in the tumor resection cavity is a recently described complication associated with the use of BCNU wafers. There is currently no report in which successful management of this complication without additional surgical intervention is described.

The authors describe four patients in whom postoperative cysts developed in the tumor resection cavity after placement of BCNU wafers. These include a 38-year-old man with a left frontoparietal tumor, a 48-year-old man with a right frontal lobe tumor, a 78-year-old man with a left parietooccipital tumor, and a 61-year-old woman with a left frontotemporal tumor. Histopathological studies of biopsy samples revealed malignant glioma in each patient. All four patients had unremarkable perioperative courses, were discharged within 3 to 8 days of surgery, and subsequently returned with acute neurological deterioration. Follow-up magnetic resonance (MR) imaging demonstrated cyst formation with significant mass effect at the previous resection site. Three patients were treated with high-dose dexamethasone and returned to their neurological baseline over an 8-day period. The fourth patient improved after surgical drainage and biopsy sampling of the cyst, which revealed no evidence of infection or recurrent tumor, but again sought medical care 2 weeks later with cyst recurrence necessitating high-dose steroid therapy. On MR images at least a 30% reduction in cyst size was demonstrated in all four patients, each of whom remained clinically stable at 2, 6, 6, and 4 months of follow-up review.

Neurosurgeons should be aware of the potential for postoperative cyst formation accompanied by clinically significant mass effect after BCNU wafer implantation, as well as the potential for successful nonsurgical management leading to clinical and radiological improvement.
Routine intraoperative angiography during aneurysm surgery
Authors: Chiang Veronica L. , Gailloud Phillipe , Murphy Kieran J. , Rigamonti Daniele , Tamargo Rafael J.
Published: May 2009

Object. The routine use of intraoperative angiography as an aid in the surgical treatment of aneurysms is uncommon. The advantages of the ability to visualize residual aneurysm or unintended occlusion of parent vessels intraoperatively must be weighed against the complications associated with repeated angiography and prolonged vascular access. The authors reviewed the results of their routine use of intraoperative angiography to determine its safety and efficacy.

Methods. Prospectively gathered data from all aneurysm cases treated surgically between January 1996 and June 2000 were reviewed. A total of 303 operations were performed in 284 patients with aneurysms; 24 patients also underwent postoperative angiography. Findings on intraoperative angiographic studies prompted reexploration and clip readjustment in 37 (11%) of the 337 aneurysms clipped. Angiography revealed parent vessel occlusion in 10 cases (3%), residual aneurysm in 22 cases (6.5%), and both residual lesion and parent vessel occlusion in five cases (1.5%). When compared with subsequent postoperative imaging, false-negative results were found on two intraoperative angiograms (8.3%) and a false-positive result was found on one (4.2%). Postoperative angiograms obtained in both false-negative cases revealed residual anterior communicating artery aneurysms. Both of these aneurysms also subsequently rebled, requiring reoperation. In the group that underwent intraoperative angiography, in 303 operations eight patients (2.6%) suffered complications, of which only one was neurological.

Conclusions. In the surgical treatment of intracranial aneurysms, the use of routine intraoperative angiography is safe and helpful in a significant number of cases, although it does not replace careful intraoperative inspection of the surgical field.
Cerebral oxygen and microdialysis monitoring during aneurysm surgery: effects of blood pressure, cerebrospinal fluid drainage, and temporary clipping on infarction
Authors: Kett-White Rupert , Hutchinson Peter J. , Al-Rawi Pippa G. , Czosnyka Marek , Gupta Arun K. , Pickard John D. , Kirkpatrick Peter J.
Published: May 2009

Object. The aim of this study was to investigate potential episodes of cerebral ischemia during surgery for large and complicated aneurysms, by examining the effects of arterial temporary clipping and the impact of confounding variables such as blood pressure and cerebrospinal fluid (CSF) drainage.

Methods. Brain tissue PO2, PCO2, and pH, as well as temperature and extracellular glucose, lactate, pyruvate, and glutamate were monitored in 46 patients by using multiparameter sensors and microdialysis. Baseline data showed that brain tissue PO2 decreased significantly, below a mean arterial pressure (MAP) threshold of 70 mm Hg. Further evidence of its relationship with cerebral perfusion pressure was shown by an increase in mean brain tissue PO2 after drainage of CSF from the basal cisterns (Wilcoxon test, p < 0.01). Temporary clipping was required in 31 patients, with a mean total duration of 14 minutes (range 3–52 minutes), causing brain tissue PO2 to decrease and brain tissue PCO2 to increase (Wilcoxon test, p < 0.01). In patients in whom no subsequent infarction developed in the monitored region, brain tissue PO2 fell to 11 mm Hg (95% confidence interval 8–14 mm Hg). A brain tissue PO2 level below 8 mm Hg for 30 minutes was associated with infarction in any region (p < 0.05 according to the Fisher exact test); other parameters were not predictive of infarction. Intermittent occlusions of less than 30 minutes in total had little effect on extracellular chemistry. Large glutamate increases were only seen in two patients, in both of whom brain tissue PO2 during occlusion was continuously lower than 8 mm Hg for longer than 38 minutes.

Conclusions. The brain tissue PO2 decreases with hypotension, and, when it is below 8 mm Hg for longer than 30 minutes during temporary clipping, it is associated with increasing extracellular glutamate levels and cerebral infarction.
Biochemical characterization of pediatric brain tumors by using in vivo and ex vivo magnetic resonance spectroscopy
Authors: Tzika A. Aria , Cheng Leo Ling , Goumnerova Liliana , Madsen Joseph R. , Zurakowski David , Astrakas Loukas G. , Zarifi Maria K. , Scott R. Michael , Anthony Douglas C. , Gonzalez R. Gilberto , Black Peter McL.
Published: May 2009

Object. Magnetic resonance (MR) spectroscopy provides biochemical information about tumors. The authors sought to determine the relationship between in vivo and ex vivo biochemical characterization of pediatric brain tumors by using MR spectroscopy. Their hypothesis was that ex vivo MR spectroscopy provides a link between in vivo MR spectroscopy and neuropathological analysis.

Methods. In vivo proton MR spectroscopy was performed before surgery in 11 patients with neuroepithelial tumors. During resection, a total of 40 tumor biopsy samples were obtained from within the volume of interest identified on in vivo MR spectroscopy and were frozen immediately in liquid nitrogen. High-Resolution Magic Angle Spinning (HRMAS) was used to perform ex vivo MR spectroscopy in these 40 tumor biopsy samples. Neuropathological analysis was performed using the same biopsy samples, and the tumors were classified as ependymoma, choroid plexus carcinoma, pineoblastoma (one each), and pilocytic astrocytoma, medullobastoma, low-grade glioma, and glioblastoma multiforme (two each).

Ex vivo HRMAS MR spectroscopy improved line widths and line shapes in the spectra, compared with in vivo MR spectroscopy. Choline (Cho) detected in vivo corresponded to three different peaks ex vivo (glycerophosphocholine, phosphocholine [PCho], and Cho). Metabolite ratios from in vivo spectra correlated with ratios from ex vivo spectra (Pearson correlation coefficient range r = 0.72–0.91; p ≤ 0.01). Metabolite ratios from ex vivo spectra, such as PCho/total creatine (tCr) and lipid/tCr, correlated with the percentage of cancerous tissue and percentage of tumor necrosis, respectively (r = 0.84; p ≤ 0.001).

Conclusions. Agreement between in vivo and ex vivo MR spectroscopy indicates that ex vivo HRMAS MR spectroscopy can improve resolution of this modality and provide a link between in vivo MR spectroscopy and neuropathological analysis.
Complications of endoscopic third ventriculostomy
Authors: Schroeder Henry W. S. , Niendorf Wulf-Rüdiger , Gaab Michael R.
Published: May 2009

Object. The purpose of this prospective investigation was to determine the rate of complications associated with endoscopic third ventriculostomy (ETV).

Methods. Between March 1993 and October 2001, 193 ETVs were performed in 188 patients at a single institution. The age of the patients ranged from 1 month to 85 years (mean age 39 years). One procedure had to be abandoned because a severe venous hemorrhage blurred the surgeon's view; however, third ventriculostomy was successfully accomplished in that patient 14 days later. In addition, there were two cases in which significant venous hemorrhages could be controlled endoscopically by using irrigation. Postoperative imaging revealed three subdural collections, one tiny thalamic contusion, one cortical hemorrhage at the puncture site, and one severe subarachnoid hemorrhage (SAH). There were two deaths (1% mortality rate) related to the endoscopic procedure; causes of death were one SAH from a torn basilar perforating artery and one wound infection leading to meningitis and septic multiorgan failure. Three permanent deficits occurred (confusion, oculomotor palsy, and diabetes insipidus [1.6% permanent morbidity rate]). Transient deficits included four cases of meningitis, three cases of cerebrospinal fluid leak, two cases of herniation syndrome, two cases of confusion, one case in which there was a decrease of consciousness, two cases of oculomotor palsy, and one case in which there was loss of thirst (7.8% transient morbidity rate). Misplacement of the fenestration was the main reason for severe complications. During the course of the study, the complication rate dropped significantly (no incidences of mortality or permanent morbidity occurred during the last 100 procedures).

Conclusions. All permanent and fatal complications occurred during the authors' very early experience, indicating that a steep learning curve was associated with the procedure. Endoscopic third ventriculostomy, if performed correctly, is a safe, simple, and effective treatment option for various forms of noncommunicating hydrocephalus.
Magnetic resonance neurography studies of the median nerve before and after carpal tunnel decompression
Authors: Cudlip Simon A. , Howe Franklyn A. , Clifton Andrew , Schwartz Martin S. , Bell B. Anthony
Published: May 2009

Object. Recently developed novel MR protocols called MR neurography, which feature conspicuity for nerve, have been shown to demonstrate signal change and altered median nerve configuration in patients with median nerve compression. The postoperative course following median nerve decompression can be problematic, with persistent symptoms and abnormal results on electrophysiological studies for some months, despite successful surgical decompression. The authors undertook a prospective study in patients with carpal tunnel syndrome, correlating the clinical, electrophysiological, and MR neurography findings before and 3 months after surgery.

Methods. Thirty patients and eight control volunteers were recruited to the study. The MR neurography consisted of axial and sagittal images (TR = 2000 msec, TE = 60 msec) obtained using a temporomandibular surface coil, fat saturation, and flow suppression. Maximum intensity projection images were used to follow the median nerve through the carpal tunnel in the sagittal plane.

Magnetic resonance neurography in patients with carpal tunnel syndrome demonstrated proximal swelling (p < 0.001) and high signal change in the nerve, together with increased flattening ratios (p < 0.001) and loss of nerve signal in the distal carpal tunnel (p < 0.05). Sagittal images were very effective in precisely demonstrating the site and severity of nerve compression. After surgery, division of the flexor retinaculum could be demonstrated in all cases. Changes in nerve configuration, including increased cross-sectional area, and reduced flattening ratios (p < 0.001) were seen in all patients. In many cases restoration of the T2 signal intensity toward that of controls was seen in the median nerve in the distal carpal tunnel. Sagittal images were excellent in demonstrating expansion of the nerve at the site of surgical decompression.

Conclusions. In this study the authors suggest that MR neurography is an effective means of both confirming compression of the median nerve and its successful surgical decompression in patients with carpal tunnel syndrome. This modality may prove useful in the assessment of unconfirmed or complex cases of carpal tunnel syndrome both before and after surgery.
Functional benefits and cost/benefit analysis of continuous intrathecal baclofen infusion for the management of severe spasticity
Authors: Sampson Fiona C. , Hayward Andrew , Evans Gillian , Morton Richard , Collett Beverly
Published: May 2009

Object. Intrathecally delivered baclofen has been used as a treatment for severe spasticity since 1984. Despite this, there are uncertainties surrounding the benefits of treatment and the costs involved. The authors assessed the evidence of benefits and identified costs and the cost/benefit ratio for continuous intrathecal baclofen infusion in the treatment of severe spasticity.

Methods. A systematic literature review was conducted to estimate the effect of continuous intrathecal baclofen infusion on function and quality-of-life (QOL) measures in patients with severe spasticity. Outcomes were related to standard QOL scores to estimate potential gains in quality-adjusted life years (QALYs). Information on the costs of continuous intrathecal baclofen infusion was obtained from hospitals in the United Kingdom. This information was combined to estimate the cost/benefit ratio for the use of continuous intrathecal baclofen infusion in patients with different levels of disability from severe spasticity.

Studies indicate that bedbound patients are likely to improve their mobility and become able to sit out of bed. Patients with severe spasm-related pain are likely to have major improvement or complete resolution of this pain. Many other benefits are also reported. Such benefits are related to costs per QALY in the range of £6900 to £12,800 ($10,550–$19,570 US).

Conclusions. In carefully selected patients who have not responded to less invasive treatments, continuous intrathecal baclofen infusion is likely to lead to worthwhile functional benefits. Continuous intrathecal baclofen infusion has an acceptable cost/benefit ratio compared with other interventions that are funded by the health service.
Stilbazulenyl nitrone, a novel azulenyl nitrone antioxidant, improved neurological deficit and reduced contusion size after traumatic brain injury in rats
Authors: Belayev Ludmila , Becker David A. , Alonso Ofelia F. , Liu Yitao , Busto Raul , Ley James J. , Ginsberg Myron D.
Published: May 2009

Object. Stilbazulenyl nitrone (STAZN) is a second-generation azulenyl nitrone that has markedly enhanced antioxidant properties compared with those of conventional alpha-phenyl nitrones. In this study, the authors assessed the potential efficacy of STAZN in a rodent model of fluid-percussion brain injury, which results in a consistent cortical contusion.

Methods. After anesthesia had been induced in normothermic Sprague—Dawley rats (brain temperature 36–36.5°C) by halothane—nitrous oxide, the animals were subjected to a right parietooccipital parasagittal fluid-percussion injury (1.5–2 atm). The agent (STAZN, 30 mg/kg; eight animals) or vehicle (dimethyl sulfoxide; eight animals) was administered intraperitoneally at 5 minutes and 4 hours after trauma. The neurological status of each rat was evaluated on Days 1, 2, and 7 postinjury (normal score 0, maximum injury 12). Seven days after trauma, the rat brains were perfusion fixed, coronal sections at various levels were digitized, and areas of contusion were measured. Treatment with STAZN significantly improved neurological scores on Days 2 and 7 postinjury compared with vehicle-treated rats. Administration of STAZN also significantly reduced the total contusion area by 63% (1.8 ± 0.5 mm2 in STAZN-treated animals compared with 4.8 ± 2.1 mm2 in vehicle-treated animals; p = 0.04) and the deep cortical contusion area by 60% (1.2 ± 0.2 mm2 in STAZN-treated animals compared with 2.9 ± 1.2 mm2 in vehicle-treated animals; p = 0.03). By contrast, hippocampal cell loss in the CA3 sector was unaffected by STAZN treatment.

Conclusions. Therapy with STAZN, a novel potent antioxidant, administered following traumatic brain injury, markedly improves neurological and histological outcomes. Azulenyl nitrones appear to represent a promising class of neuroprotective agents for combating this devastating condition.
Heme oxygenase-1 gene therapy for prevention of vasospasm in rats
Authors: Ono Shigeki , Komuro Taro , Macdonald R. Loch
Published: May 2009

Object. Hemoglobin causes contraction of cerebral arteries and is also believed to cause vasospasm after subarachnoid hemorrhage (SAH). The goal in this study was to determine if overexpression of heme oxygenase-1 (HO-1), the principal enzyme involved in the metabolism of hemoglobin, would reduce contractions of cerebral arteries brought on by hemoglobin and decrease vasospasm after experimental SAH.

Methods. Injection of adenovirus expressing HO-1 (Ad5HO-1) into the cisterna magna of rats produced a significant increase in expression of HO-1 messenger RNA, and protein and HO-1 activity in the basilar artery ([BA]; p < 0.05 for each measure compared with vehicle and/or control virus, according to analysis of variance or unpaired t-test). Injection of adenovirus expressing β-galactosidase (Ad-βGal) produced only mild, statistically nonsignificant increases. The HO-1 immunoreactivity was localized to the BA adventitia after injection of Ad5HO-1 or Ad-βGal. Injection of Ad5HO-1 and Ad-βGal increased the baseline diameter of the BA (measured directly via a transclival window) and brainstem cerebral blood flow (CBF), measured by laser Doppler flowmetry, compared with vehicle. Contraction of the BA after addition of hemoglobin was significantly inhibited, reduction in brainstem CBF was significantly prevented, and carboxyhemoglobin concentration was significantly increased in rats injected with Ad5HO-1 compared with Ad-βGal and vehicle. Vasospasm was significantly ameliorated in rats in which Ad5HO-1 was injected into the cisterna magna at the time of SAH in a double-hemorrhage model.

Conclusions. These results show that overexpression of HO-1 inhibits arterial contractions induced by hemoglobin and can reduce vasospasm after experimental SAH.
Neuromuscular choristoma of the sciatic nerve
Authors: Maher Cormac O. , Spinner Robert J. , Giannini Caterina , Scheithauer Bernd W. , Crum Brian A.
Published: May 2009

✓ The authors report the findings of a neuromuscular choristoma of the sciatic nerve in an otherwise healthy 18-year-old man who presented with sensorimotor symptoms and deformities of the right leg and foot. Only a few cases of this rare tumor, also known as “neuromuscular hamartoma” or “benign triton tumor,” have been reported in the surgical literature. The authors discuss the clinical presentation, radiological findings, pathological diagnosis, and surgical rationale for this case and review the associated literature.
Primary Burkitt lymphoma of the brain in an immunocompetent patient
Authors: Monabati Ahmad , Rakei S. Mohammad , Kumar Perikala V. , Taghipoor Moosa , Rahimi Abbas
Published: May 2009

✓ Primary central nervous system (CNS) lymphoma is rare and is most often seen in immunodeficient patients. The majority of these tumors are the non-Hodgkin type and are high grade. Primary Burkitt lymphoma of the CNS in immunocompetent individuals has rarely been reported. The authors treated a 49-year-old woman who presented with left-sided weakness that had lasted 1.5 months. Magnetic resonance imaging revealed an oval mass in the left parietal region, with central necrosis and peripheral edema, and no attachment to the leptomeninges or ependyma. Pathological examination yielded a diagnosis of typical Burkitt lymphoma. Six months postoperatively, the patient is ambulatory and has improving neurological signs.

This is a typical case of primary Burkitt lymphoma of the brain in an immunocompetent patient, which is a very rare event. The imaging pattern of the lesion is not typical of brain lymphomas and can result in an incorrect preoperative diagnosis of other brain tumors, such as glioblastoma multiforme. The patient's treatment and follow-up review are discussed.
Tunneled lumbar drain
Authors: Hahn Michael , Murali Raj , Couldwell William T.
Published: May 2009

✓ The authors report a simple and rapid procedure for tunneling a lumbar drain subcutaneously to facilitate chronic cerebrospinal fluid (CSF) drainage. A standard lumbar puncture (LP) is performed with a large-bore Tuohy needle (14- to 16-gauge), the drainage catheter is advanced into the subarachnoid space, and the needle is removed. The free Tuohy needle is then passed from a lateral position and brought out through the initial LP site. The free catheter is fed through the needle, and the needle is removed. The drain is attached to an external drainage bag in the usual manner. The authors have found this method particularly useful in some skull base and spinal surgical applications in which longer term continuous CSF drainage is desired.
George J. Heuer: forgotten pioneer neurosurgeon at The Johns Hopkins Hospital
Authors: Borden William B. , Tamargo Rafael J.
Published: May 2009

✓ George J. Heuer was a pioneer in neurosurgery at The Johns Hopkins Hospital in the early 20th century; he trained under Harvey Cushing and acted as a mentor to Walter Dandy. In his early career, Heuer focused on research and clinical work in the field of neurosurgery and temporarily led the neurosurgery section at Johns Hopkins. One of his most important contributions to neurosurgery was the modern frontotemporal craniotomy. This elegant craniotomy, which initially was used to approach chiasmal tumors, developed into the modern frontosphenotemporal craniotomy, which neurosurgeons use to approach numerous tumors as well as most aneurysms. Although Dandy is frequently credited with inventing this operation, his article detailing the new approach clearly attributes its origin to Heuer, who was serving in World War I when the new technique was presented.

Although he had hoped to lead the neurosurgical section at Johns Hopkins permanently, he returned from military service to find that Dandy had been appointed to this position. Heuer subsequently advanced to a distinguished career in general surgery as the chairman of surgery at two institutions, and was known for his contributions to surgical education. Throughout his academic years, Heuer continued to operate on the nervous system and to perform spinal cord and peripheral nerve surgery. He played an important role along with Cushing and Dandy in the creation of neurosurgery as a specialty, but he is rarely given credit for this accomplishment. The authors describe Heuer's contributions to neurosurgery as well as his distinguished surgical career.