bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of intracerebral hemorrhage after carotid endarterectomy
Authors: Henderson Robert D. , Phan Thanh G. , Piepgras David G. , Wijdicks Eelco F. M.
Published: May 2009

Object. Intracerebral hemorrhage (ICH) is an uncommon complication of carotid endarterectomy (CEA), and carries a high rate of mortality and morbidity. Traditionally, attention has been focused on the cerebral hyperperfusion syndrome (HPS) as the leading cause of ICH after CEA. Other mechanisms, such as a perioperative cerebral ischemic event, cerebral infarction, and use of postoperative anticoagulation therapy, may also be important.

Methods. The authors performed a retrospective case control study to identify factors leading to ICH after CEA. Records of CEAs performed over the past 10 years at the Mayo Clinic were searched for occurrences of ICH within 30 days of the procedure. The relationship of ICH to known cerebrovascular risk factors, perioperative electroencephalographic studies, and 133Xe cerebral blood flow (CBF) studies was compared with that in a control group. Hyperperfusion was defined as hypertension with symptoms of either severe headache, seizures, or confusion, or a doubling of intraoperative CBF values. The clinical history and imaging of ischemic events and the ICH were carefully reviewed to determine the possible underlying mechanism(s).

Twelve (0.4%) of 2747 patients who underwent CEAs suffered a postoperative ICH. A doubling of CBF values was found in five of eight cases in which CBF studies were performed, and occurred more commonly in the patients with ICH than in controls. Clinical symptoms of the HPS were less common (three cases). A perioperative cerebral ischemic event (four cases) and anticoagulation therapy (six cases) were other contributors to a subsequent ICH. Seven of the 12 patients with ICHs died and five achieved a moderate outcome.

Conclusions. An ICH following CEA is an unusual complication that occurs in the setting of hyperperfusion, perioperative cerebral ischemia, anticoagulation therapy, or multiple mechanisms. Identification of CBF doubling at surgery may assist in identifying patients at risk for ICH following CEA.
Treatment window for hypothermia in brain injury
Authors: Markgraf Carrie G. , Clifton Guy L. , Moody Melanie R.
Published: May 2009

Object. The goal of this study was to evaluate the therapeutic window for hypothermia treatment following experimental brain injury by measuring edema formation and functional outcome.

Methods. Traumatic brain injury (TBI) was produced in anesthetized rats by using cortical impact injury. Edema was measured in the ipsilateral and contralateral hemispheres by subtracting dry weight from wet weight, and neurological function was assessed using a battery of behavioral tests 24 hours after TBI. In injured rats, it was found that brain water levels were elevated at 1 hour postinjury, compared with those in sham-injured control animals, and that edema peaked at 24 hours and remained elevated for 4 days. Hypothermia (3 hours at 30°C) induced either immediately after TBI or 60 minutes after TBI significantly reduced early neurological deficits. Delay of treatment by 90 or 120 minutes postinjury did not result in this neurological protection. Immediate administration of hypothermia also significantly decreased the peak magnitude of edema at 24 hours and 48 hours postinjury, compared with that in normothermic injured control animals. When delayed by 90 minutes, hypothermia did not affect the pattern of edema formation.

Conclusions. When hypothermia was administered immediately or 60 minutes after TBI, injured rats showed an improvement in functional outcome and a decrease in edema. Delayed hypothermia treatment had no effect on functional outcome or on edema.
Combination of stereotactic radiosurgery and cytokine gene—transduced tumor cell vaccination: a new strategy against metastatic brain tumors
Authors: Nakahara Norimoto , Okada Hideho , Witham Timothy F. , Attanucci Jason , Fellows Wendy K. , Chambers William H. , Niranjan Ajay , Kondziolka Douglas , Pollack Ian F.
Published: May 2009

Object. To determine if the combination of radiosurgery and tumor cell vaccine would enhance the therapy of metastatic lesions of the central nervous system (CNS), the authors examined the antitumoral effects of radiosurgery and cytokine-transduced tumor cell vaccine.

Methods. Fifty-five rats underwent intracranial implantation of 5 × 103 MADB106 cells. On Day 3 after tumor implantation, 34 rats were inoculated in the flank with nonirradiated MADB106 cells that had been retrovirally transduced to express granulocyte-macrophage colony-stimulating factor or interleukin-4. Twenty-seven rats (17 animals that had received the vaccine and 10 that had not) underwent radiosurgery performed using a gamma knife at maximum doses of 32 Gy on Day 5.

No animals in the untreated group or in the vaccine-alone groups survived longer than 21 days. Animals treated by radiosurgery alone displayed prolonged survival in comparison with untreated animals (p < 0.0001), but only one of 10 animals survived longer than 55 days. In contrast, 14 of 17 animals that received the combination therapy of radiosurgery and vaccination survived longer than 55 days (p = 0.0003 compared with animals that underwent radiosurgery alone). On Day 55, the long-term survivors were challenged by parental MADB106 cells, which were implanted in the contralateral hemisphere. All animals from the combination therapy groups survived longer than 50 days after this challenge, but the single survivor from the radiosurgery-alone group died of tumor growth in 27 days.

Conclusions. The combination of radiosurgery and cytokine gene—transduced tumor cell vaccine markedly prolonged animal survival and protected animals from a subsequent challenge by parental tumor cells placed in the CNS. The data provided by this study indicate that this combination therapy represents a strategy that may have clinical applicability for single and/or multiple metastatic brain tumors.
Surgical landmarks for the proximal portion of the axillary nerve
Authors: Tubbs R. Shane , Oakes W. Jerry , Blount Jeffrey P. , Elton Scott , Salter George , Grabb Paul A.
Published: May 2009

Object. The proximal segment of the axillary nerve (ANp) is often difficult to identify without extensive dissection deep into the axilla. The present study was performed to find reliable surgical landmarks for this nerve.

Methods. Thirty dissections of human cadavers were performed to determine the relationships between the ANp and specific anatomical structures.

The authors found that the ANp is consistently located within an anatomical triangle constructed by lines passing between the coracobrachialis and pectoralis minor muscles and the axillary artery. In addition, the ANp was routinely found 4 cm distal to the coracoid process of the scapula.

Conclusions. These findings should assist the surgeon in locating the ANp during brachial plexus reconstruction.
Hearing restoration with auditory brainstem implants after radiosurgery for neurofibromatosis Type 2
Authors: Kalamarides Michel , Grayeli Alexis Bozorg , Bouccara Didier , Dahan Emmanuelle Ambert , Sollmann Wolf Peter , Sterkers Olivier , Rey Alain
Published: May 2009

✓ The auditory brainstem implant (ABI) is designed to restore useful auditory sensations in patients with neurofibromatosis Type 2 (NF2). The implantation is usually performed at the time of tumor removal in patients who do not undergo radiation treatment. The authors evaluated the performance of ABIs in three patients with NF2 in whom vestibular schwannoma continued to grow after radiation treatment. These three patients with NF2 received a 21-channel ABI; a translabyrinthine approach was used for both the tumor removal and the ABI placement. The interval between radiosurgery and the tumor removal plus device implantation ranged from 2 to 11 years. In all cases, the tumor was growing and the patients presented with total deafness. The mean number of active electrodes in these three patients was equivalent to the average results reported in other patients who received ABIs. The patients in this study used the ABI regularly for everyday life and obtained useful levels of environmental sound recognition. It is concluded that hearing function can be rehabilitated using ABIs in patients with NF2, even if radiosurgery fails to control the tumor growth.
Atypical hemifacial microsomia associated with Chiari I malformation and syrinx: further evidence indicating that Chiari I malformation is a disorder of the paraaxial mesoderm
Authors: Mesiwala Ali H. , Shaffrey Christopher I. , Gruss Joseph S. , Ellenbogen Richard G.
Published: May 2009

✓ The authors present the first known reported case of hemifacial microsomia associated with a Chiari I malformation and syrinx. A 14-year-old girl presented with progressive torticollis of 3 years' duration and headaches exacerbated by exercise. Computerized tomography scanning and magnetic resonance imaging revealed extensive craniofacial and vertebral abnormalities, including aplasia of the floor of the left middle fossa and posterior fossa cranium, articulation of the left mandibular condyle with the left temporal lobe, and progressive development of a Chiari I malformation with associated syringomyelia. The patient first underwent posterior fossa decompression, duraplasty, and occipitocervical fusion. This procedure was later followed by reconstruction of the floor of the left middle fossa and temporomandibular joint. The patient's outcome was excellent. In this case report the authors review the complex embryological development of craniofacial and craniovertebral structures, and emphasize the use of a staged approach to treat pathophysiological consequences of this congenital anomaly.
Fibrous meningioma in a patient with von Hippel—Lindau disease: a genetic analysis
Authors: Governale Lance S. , Vortmeyer Alexander O. , Zhuang Zhengping , Oldfield Edward H.
Published: May 2009

✓ Meningioma has been included in the constellation of tumors associated with von Hippel—Lindau (VHL) disease in previously published reports. It is unclear whether these tumors are an uncommon component of VHL disease or are more readily detected in these patients because of the frequency with which they undergo central nervous system imaging as part of the routine management of VHL disease. The authors report the case of a patient with VHL disease in whom a progressively enlarging supratentorial mass developed and was diagnosed as a hemangioblastoma because of its appearance on serial magnetic resonance images. At surgery the tumor displayed the typical features of a meningioma and was given the histological diagnosis of fibrous meningioma. Single-stranded conformational polymorphism analysis of the tumor DNA revealed a loss of heterozygosity at the neurofibromatosis Type 2 gene locus, known to be associated with sporadically occurring meningiomas. Despite this finding, the VHL gene locus on the allele from the patient's unaffected parent was normal. Thus it is unlikely that the occurrence of this patient's fibrous meningioma was associated with underlying VHL disease. Given the high frequency of neuroimaging sessions in patients with VHL disease, some supratentorial lesions that have been given radiological diagnoses of hemangioblastomas may be incidental meningiomas.
Recovery from complete hemiplegia following resection of a retrocentral metastasis: the prognostic value of intraoperative cortical stimulation
Authors: Duffau Hugues
Published: May 2009

✓ The goal in this study was to determine if intraoperative electrical stimulation mapping is useful during surgical resection of lesions located in the central region, even in cases of preoperative hemiplegia. This 45-year-old man with a retrocentral metastasis from an embryonal carcinoma of the testis suffered an acute complete hemiplegia after intratumoral bleeding. Emergency surgery was performed with the aid of intraoperative motor mapping despite the preoperative deficit. Cortical stimulations (CSs) elicited motor responses, allowing the detection and hence preservation of the primary motor area during tumor removal. Postoperatively, the patient recovered almost completely within 1 week; the tumor resection was total.

It is possible that CSs give an early and valuable prognostic indicator of motor recovery in cases of complete hemiplegia, at least in patients with acute onset and short duration of the deficit. Consequently, if motor responses can be elicited by CSs, it becomes mandatory for the surgeon to respect the primary motor area despite the preoperative hemiplegia, with the aim of preserving the chances of an eventual recovery.
Anaglyphic three-dimensional stereoscopic printing: revival of an old method for anatomical and surgical teaching and reporting
Authors: Ribas Guilherme Carvalhal , Bento Ricardo Ferreira , Rodrigues Aldo Junqueira
Published: May 2009

✓ The authors describe how to use the three-dimensional (3D) anaglyphic method to produce stereoscopic prints for anatomical and surgical teaching and reports preparation by using currently available nonprofessional photographic and computer methods.

As with any other method of producing stereoscopic images, the anaglyphic procedure is based on the superimposition of two slightly different images of the object to be reproduced, one seen more from a left-sided point of view and the other seen more from a right-sided point of view. The pictures are obtained using a single camera, which following the first shot can be slid along a special bar for the second shot, or by using two cameras affixed to a surgical microscope. After the images have been distinguished from each other by applying different complementary color dyes, the images are scanned and superimposed on each other with the aid of nonprofessional imaging-manipulation software used on a standard personal computer (PC), and are printed using a standard printer. To be seen stereoscopically, glasses with colored lenses, normally one red and one blue, have to be used.

Stereoscopic 3D anaglyphic prints can be produced using standard photographic and PC equipment; after some training, the prints can be easily reproduced without significant cost and are particularly helpful to disclose the 3D character of anatomical structures.
Double-barreled tack suture procedure in carotid endarterectomy
Authors: Kim Sun Ho , Park Soo Chul , Lee Kyu Chang
Published: May 2009

✓ The authors have developed a double-barreled tack suture procedure for carotid endarterectomy with minimal modification of a conventional needle holder. With this method surgeons can make two stitches simultaneously by using two needles threaded with double-armed suture material, which are held tightly in a parallel fashion in the jaws of a modified needle holder.

This method is very effective in preventing the buckling of the intimal wall of the arterectomized distal internal carotid artery. Also, it reduces the tack suture time markedly compared with the conventional tack suture method.
The history and evolution of transsphenoidal surgery
Authors: Liu James K. , Das Kaushik , Weiss Martin H. , Laws Edward R. , Couldwell William T.
Published: May 2009

✓ Initial attempts at transcranial approaches to the pituitary gland in the late 1800s and early 1900s resulted in a mortality rate that was generally considered prohibitive. Schloffer suggested the use of a transsphenoidal route as a safer, alternative approach to the sella turcica. He reported the first successful removal of a pituitary tumor via the transsphenoidal approach in 1906. His procedure underwent a number of modifications by interested surgeons, the culmination of which was A. E. Halstead's description in 1910 of a sublabial gingival incision for the initial stage of exposure. From 1910 to 1925, Cushing, combining a number of suggestions made by previous authors, refined the transsphenoidal approach and used it to operate on 231 pituitary tumors, with a mortality rate of 5.6%. As he developed increasing expertise with transcranial surgery, however, Cushing reduced his mortality rate to 4.5%. With the transcranial approach, he was able to verify suprasellar tumors and achieve better decompression of the optic apparatus, resulting in better recovery of vision and a lower recurrence rate. As a result he and most other neurosurgeons at the time abandoned the transnasal in favor of the transcranial approaches.

Norman Dott, a visiting scholar who studied with Cushing in 1923, returned to Edinburgh, Scotland, and continued to use the transsphenoidal procedure while others pursued transcranial approaches. Dott introduced the procedure to Gerard Guiot, who published excellent results with the transsphenoidal approach and revived the interest of many physicians throughout Europe in the early 1960s. Jules Hardy, who used intraoperative fluoroscopy while learning the transsphenoidal approach from Guiot, then introduced the operating microscope to further refine the procedure; he thereby significantly improved its efficacy and decreased surgical morbidity. With the development of antibiotic drugs and modern microinstrumentation, the transsphenoidal approach became the preferred route for the removal of lesions that were confined to the sella turcica. The evolution of the transsphenoidal approaches and their current applications and modifications are discussed.
Pioneers in the development of transsphenoidal surgery: Theodor Kocher, Oskar Hirsch, and Norman Dott
Authors: Lanzino Giuseppe , Laws Edward R.
Published: May 2009

✓ The development of new scientific concepts and techniques is usually the result of a progressive evolution. The transsphenoidal approach to pituitary lesions is no exception. Several pioneers contributed to its development and its eventual and nearly unconditional acceptance. In this historical vignette, the contributions of three master surgeons, Theodor Kocher, Oskar Hirsch, and Norman Dott, are reviewed.
Outcome prediction with serum intercellular adhesion molecule-1 levels after aneurysmal subarachnoid hemorrhage
Authors: Mack William J. , Mocco J , Hoh Daniel J. , Huang Judy , Choudhri Tanvir F. , Kreiter Kurt T. , Lozier Alan , Opperman Marcello , Poisik Alexander , Yorgason Joshua , Solomon Robert A. , Mayer Stephan A. , Connolly E. Sander
Published: May 2009

Object. Although upregulated adhesion molecule expression has been demonstrated in experimental models of subarachnoid hemorrhage (SAH) and in the cerebrospinal fluid of patients with aneurysmal SAH, the clinical significance of these proinflammatory findings remains unclear. The authors hypothesize that 1) serum levels of soluble intercellular adhesion molecule-1 (ICAM-1) are increased in all patients with aneurysmal SAH shortly after the hemorrhagic event, and 2) elevated soluble ICAM-1 values are associated with poor patient outcome, even when controlling for the severity of the initial hemorrhagic insult.

Methods. One hundred one patients were prospectively enrolled and stratified according to their admission Hunt and Hess grade and functional status at discharge (modified Rankin Scale [mRS] score). Soluble ICAM-1 levels were determined every other day for 12 days post-SAH by using the enzyme-linked immunosorbent assay. Early soluble ICAM-1 levels (post-SAH Days 2–4) were increased compared with levels in control patients without SAH (p < 0.05). Patients with aneurysmal SAH who had a poor outcome (mRS Grades 4–6) had significantly higher soluble ICAM-1 levels over the first 2 weeks post-SAH compared with patients who had a good outcome (mRS Grades 0–3, p < 0.01). This association with outcome was predicted by late increases (Day 6, p = 0.07; Days 8–12, p < 0.05) rather than early increases (p = not significant) and was best seen in patients with Hunt and Hess Grades I and II, in whom only those with poor outcomes demonstrated delayed ICAM-1 elevations (p < 0.05).

Conclusions. These data demonstrate a correlation between soluble ICAM-1 levels and functional outcome following aneurysmal SAH that appears to be, at least in part, independent of the initial hemorrhage.
Cerebral tissue PO2 and SjvO2 changes during moderate hyperventilation in patients with severe traumatic brain injury
Authors: Imberti Roberto , Bellinzona Guido , Langer Martin
Published: May 2009

Object. The aim of this study was to investigate the effects of moderate hyperventilation on intracranial pressure (ICP), jugular venous oxygen saturation ([SjvO2], an index of global cerebral perfusion), and brain tissue PO2 (an index of local cerebral perfusion).

Methods. Ninety-four tests consisting of 20-minute periods of moderate hyperventilation (27–32 mm Hg) were performed on different days in 36 patients with severe traumatic brain injury (Glasgow Coma Scale score ≤ 8). Moderate hyperventilation resulted in a significant reduction in average ICP, but in seven tests performed in five patients it was ineffective. The response of SjvO2 and brain tissue PO2 to CO2 changes was widely variable and unpredictable. After 20 minutes of moderate hyperventilation in most tests (79.8%), both SjvO2 and brain tissue PO2 values remained above the lower limits of normality (50% and 10 mm Hg, respectively). In contrast, in 15 tests performed in six patients (16.6% of the studied population) brain tissue PO2 decreased below 10 mm Hg although the corresponding SjvO2 values were greater than 50%. The reduction of brain tissue PO2 below 10 mm Hg was favored by the low prehyperventilation values (10 tests), higher CO2 reactivity, and, possibly, by lower prehyperventilation values of cerebral perfusion pressure. In five of those 15 tests, the prehyperventilation values of SjvO2 were greater than 70%, a condition of relative hyperemia. The SjvO2 decreased below 50% in four tests; the corresponding brain tissue PO2 values were less than 10 mm Hg in three of those tests, whereas in the fourth, the jugular venous O2 desaturation was not detected by brain tissue PO2.

The analysis of the simultaneous relative changes (prehyperventilation — posthyperventilation) of SjvO2 and brain tissue PO2 showed that in most tests (75.5%) there was a reduction of both SjvO2 and brain tissue PO2. In two tests moderate hyperventilation resulted in an increase of both SjvO2 and brain tissue PO2. In the remaining 17 tests a redistribution of the cerebral blood flow was observed, leading to changes in SjvO2 and brain tissue PO2 in opposite directions.

Conclusions. Hyperventilation, even if moderate, can frequently result in harmful local reductions of cerebral perfusion that cannot be detected by assessing SjvO2. Therefore, hyperventilation should be used with caution and should not be considered safe. This study confirms that SjvO2 and brain tissue PO2 are two parameters that provide complementary information on brain oxygenation that is useful to reduce the risk of secondary damage. Changes in SjvO2 and brain tissue PO2 in opposite directions indicate that data obtained from brain tissue PO2 monitoring cannot be extrapolated to evaluate the global cerebral perfusion.
Subarachnoid hemorrhage from a ruptured anterior cerebral artery aneurysm caused by polyarteritis nodosa
Authors: Takahashi Jun C. , Sakai Nobuyuki , Iihara Koji , Sakai Hideki , Higashi Toshio , Kogure Shuji , Taniguchi Ayumi , Ueda Hatsue I. , Nagata Izumi
Published: May 2009

✓ Polyarteritis nodosa (PAN) is a rare systemic necrotizing arteritis that involves small- and medium-sized arteries in various organs. Although aneurysm formation in visceral arteries is a typical finding in PAN, intracranial aneurysms are much less common, and only a few cases of aneurysm rupture associated with this disease have been documented. In this paper, the authors report on a ruptured PAN aneurysm of the anterior cerebral artery; the lesion was trapped and resected. On histological examination, extensive fibrinoid necrosis and an inflammatory infiltration of leukocytes were seen in the aneurysm wall. To the authors' knowledge this is the first report of subarachnoid hemorrhage from a histologically confirmed PAN aneurysm.
Cervicomedullary junction compression caused by vertebral artery dolichoectasia and requiring surgical treatment
Authors: Ubogu Eroboghene E. , Chase Cheré M. , Verrees Margaret A. , Metzger Andrew K. , Zaidat Osama O.
Published: May 2009

✓ A case of progressive brainstem syndrome secondary to vertebral artery (VA) dolichoectasia is reported. The patient presented with partial bilateral abduction paralysis, which progressed to quadriparesis, ataxia, and areflexia. The initial diagnosis was stroke, but because of the patient's deterioration, a diagnosis of Miller—Fisher syndrome was made. Neuroimages obtained at that time revealed an ectatic left VA with minimal cervicomedullary compression. The patient continued to deteriorate despite medical management. Follow-up imaging demonstrated worsened cervicomedullary compression. An emergency posterior fossa neurovascular decompression was performed using a Gore-Tex sling and resulted in mild neurological improvement. This case emphasizes that early recognition and surgical intervention to prevent progressive neurological sequelae are crucial in symptomatic VA dolichoectasia.
Vestibular schwannoma growth in patients with neurofibromatosis Type 2: a longitudinal study
Authors: Mautner Victor-Felix , Baser Michael E. , Thakkar Sarang D. , Feigen Urs M. , Friedman J. M. , Kluwe Lan
Published: May 2009

Object. The factors that determine the growth rates of vestibular schwannomas (VSs) in patients with neurofibromatosis Type 2 (NF2) are unknown. The authors undertook this study to determine if clinical factors or type of constitutional NF2 mutation were associated with VS growth rates in cases of NF2.

Methods. The authors reviewed serial gadolinium-enhanced magnetic resonance (MR) images of the head and full spine of 37 patients with sporadic NF2 who had been observed over periods ranging from 0.2 to 8 years (median 3.9 years) at a specialized referral clinic for NF2. A box model was used to calculate VS volumes so that tumor growth rates could be estimated. Temperature-gradient gel electrophoresis was used to screen for constitutional NF2 mutations. The VS growth rates tended to decrease with increasing patient age at onset of signs or symptoms (r2 = 0.23, p = 0.003) and at the time the baseline gadolinium-enhanced MR image was obtained (r2 = 0.38, p < 0.001). The authors did not find significant associations between VS growth rates and the number of non-VS cerebral or spinal tumors or different types of constitutional NF2 mutations.

Conclusions. There is considerable variability in growth rates of VSs in patients with NF2, but they tend to be higher in patients who are younger at onset of signs or symptoms.
Titanium miniplates or stainless steel wire for cranial fixation: a prospective randomized comparison
Authors: Broaddus William C. , Holloway Kathryn L. , Winters Charles J. , Bullock M. Ross , Graham R. Scott , Mathern Bruce E. , Ward John D. , Young Harold F.
Published: May 2009

Object. The authors designed a study to compare low-profile titanium miniplate fixation to that in which stainless steel wire is used.

Methods. Before undergoing craniotomy, 40 patients gave informed consent and were randomized to receive either wire or miniplate fixation. After dural closure, bone flap fixation was timed. The bone flap was measured for inward or outward offset and mobility to manual pressure on its margin. Three months postoperatively the bone flap margins were graded for appearance or palpation of an offset and for the presence of burr hole depressions.

Twenty-four patients were randomized to receive miniplate fixation and 16 to receive stainless steel wire fixation. The time required for wire fixation was approximately 40% longer than that for miniplates (11.8 ± 5.1 minutes compared with 8.3 ± 5 minutes, p = 0.02). The offset of bone flaps after wire fixation was significantly greater than that with miniplates (1.6 ± 1 mm compared with 0.3 ± 0.6 mm, p < 0.001), as was the mobility of the bone flap on digital pressure (1.2 ± 0.9 mm compared with 0.2 ± 0.5 mm, p < 0.001). At the 3-month follow-up review, two of 12 patients had suboptimal results after wire fixation, whereas none of 14 patients had suboptimal results after miniplate fixation. When dichotomized for excellent or less-than-excellent postoperative results, the data were significantly better for patients who underwent miniplate fixation (p < 0.05).

Conclusions. Titanium miniplate cranial fixation provides more accurate and rigid reapproximation of the bone edges, with results that are significantly better on close inspection or palpation. The additional cost of miniplate fixation may thus be justified in many cases.
Measurement of brain tissue oxygenation performed using positron emission tomography scanning to validate a novel monitoring method
Authors: Gupta Arun K. , Hutchinson Peter J. , Fryer Tim , Al-Rawi Pippa G. , Parry Dot A. , Minhas Pawan S. , Kett-White Rupert , Kirkpatrick Peter J. , Mathews Julian C. , Downey Steve , Aigbirhio Franklin , Clark John , Pickard John D. , Menon David K.
Published: May 2009

Object. The benefits of measuring cerebral oxygenation in patients with brain injury are well accepted; however, jugular bulb oximetry, which is currently the most popular monitoring technique used has several shortcomings. The goal of this study was to validate the use of a new multiparameter sensor that measures brain tissue oxygenation and metabolism (Neurotrend) by comparing it with positron emission tomography (PET) scanning.

Methods. A Neurotrend sensor was inserted into the frontal region of the brain in 19 patients admitted to the neurointensive care unit. After a period of stabilization, the patients were transferred to the PET scanner suite where C15O, 15O2, and H215O PET scans were obtained to facilitate calculation of regional cerebral blood volume, O2 metabolism, blood flow, and O2 extraction fraction (OEF). Patients were given hyperventilation therapy to decrease arterial CO2 by approximately 1 kPa (7.5 mm Hg) and the same sequence of PET scans was repeated. For each scanning sequence, end-capillary O2 tension (PvO2) was calculated from the OEF and compared with the reading of brain tissue O2 pressure (PbO2) provided by the sensor.

In three patients the sensor was inserted into areas of contusion and these patients were eliminated from the analysis. In the subset of 16 patients in whom the sensor was placed in healthy brain, no correlation was found between the absolute values of PbO2 and PvO2 (r = 0.2, p = 0.29); however a significant correlation was obtained between the change in PbO2 (ΔPbO2) and the change in PvO2 (ΔPvO2) produced by hyperventilation in a 20-mm region of interest around the sensor (ρ = 0.78, p = 0.0035).

Conclusions. The lack of correlation between the absolute values of PbO2 and PvO2 indicates that PbO2 cannot be used as a substitute for PvO2. Nevertheless, the positive correlation between ΔPbO2 and ΔPvO2 when the sensor had been inserted into healthy brain suggests that tissue PO2 monitoring may provide a useful tool to assess the effect of therapeutic interventions in brain injury.
Bilateral high-frequency stimulation in the subthalamic nucleus for the treatment of Parkinson disease: correlation of therapeutic effect with anatomical electrode position
Authors: Voges Jürgen , Volkmann Jens , Allert Niels , Lehrke Ralph , Koulousakis Athanasios , Freund Hans-Joachim , Sturm Volker
Published: May 2009

Object. The goal of this study was to relate the degree of clinical improvement and that of energy consumption to the anatomical position of electrode poles used for long-term stimulation.

Methods. The authors conducted a retrospective analysis of 15 consecutive patients in whom targeting of the subthalamic nucleus (STN) had been performed using ventriculography, three-dimensional (3D) magnetic resonance (MR) imaging, and 3D computerized tomography, together with macrostimulation and teleradiographic control of the electrode position. In these patients the follow-up period ranged from 6 to 12 months. Postoperative improvement in contralateral motor symptoms, which was assessed by assigning a lateralized motor subscore of the Unified Parkinson's Disease Rating Scale (UPDRS), and stimulus intensity required for optimal treatment results were correlated with the intracerebral position of the active electrode pole.

Bilateral high-frequency stimulation of the STN improved the UPDRS motor score during the medication-off period by an average of 60.5% compared with that at baseline. Repeated transfer of stereotactic coordinates from postoperative teleradiography to treatment-planning MR images documented the proper localization of the most distal electrode pole (pole 0) in the targeted STN. Nevertheless, in most cases the best clinical improvement was achieved using electrode poles that were located several millimeters above the electrode tip. If the relative improvement in motor symptoms was correlated with the required electrical energy for chronic stimulation, the best coefficient was observed for active electrode poles projecting onto white matter dorsal to the STN.

Conclusions. This observation makes blocking or activation of large fiber connections arising in the STN or running nearby more likely than electrical interference with cell bodies inside the STN. Anatomical correlates may be the pallidothalamic bundle (including Field H of Forel and the thalamic fascicle), the pallidosubthalamic tract, and/or the zona incerta.
Evaluation of the healing process after dural reconstruction achieved using a free fascial graft
Authors: Tachibana Eiji , Saito Kiyoshi , Fukuta Keizo , Yoshida Jun
Published: May 2009

Object. This study was undertaken to investigate the healing process and to delineate factors important for the survival of free fascial grafts used for dural repair.

Methods. A dural defect was created in guinea pigs and then reconstructed using either a free fascial graft or an expanded polytetrafluoroethylene (ePTFE) sheet. The fascial graft was covered directly by subcutaneous tissue (Group I) or by a silicone sheet to prevent tissue ingrowth from the subcutaneous tissue (Group II). The ePTFE sheet was covered with a silicone sheet (Group III). One or 2 weeks postoperatively, the strength of the dural repair was evaluated by determining the pressure at which cerebrospinal fluid (CSF) leaked through the wound margins. The dural repair was also histologically examined. In addition, using a rat model, specimens obtained from similar reconstruction sites were immunohistochemically stained with antibodies against basic fibroblast growth factor (bFGF), epidermal growth factor, or transforming growth factor—β.

The pressures at which CSF leaked after 1 and 2 weeks, respectively, were 50 ± 14 mm Hg and 126 ± 20 mm Hg in Group I, 70 ± 16 mm Hg and 101 ± 38 mm Hg in Group II, and 0 mm Hg and 8 ± 8 mm Hg in Group III. Failure of repairs made in Group III occurred at significantly lower pressures when compared with Groups I and II. In Groups I and II, a thick fibrous tissue formed around the fascial graft. This tissue tightly adhered to adjacent dura mater. The fibrous tissue displayed a positive reaction for the presence of bFGF. In Group III, only a thin fibrous membrane surrounded the ePTFE sheet.

Conclusions. Fascial grafts tolerated extraordinary intracranial pressures at 1 week postoperatively. Free fascial grafts can heal with durable fibrous tissue without the presence of a blood supply from an overlying vascularized flap.
Association of elevated glial expression of interleukin-1β with improved survival in patients with glioblastomas multiforme
Authors: Cuny Emmanuel , Loiseau Hugues , Penchet Guillaume , Ellie Emmanuel , Arsaut Josette , Vital Anne , Vincendeau Philippe , Demotes-Mainard Jacques
Published: May 2009

Object. The aim of this study was to investigate the association of interleukin-1β (IL-1β) expression with improved survival in patients with glioblastomas multiforme (GBMs). Immune and vascular host—tumor interactions play a pivotal role in the control of tumor development, and inflammatory mechanisms may participate in the host's defense against tumor cells. Expression of proinflammatory cytokines and of inducible nitric oxide synthase (iNOS) has been noted in various types of malignant tumors, raising the possibility that endogenous expression of cytokines and the resulting cytotoxic action of sustained NO production play a role in the control of tumor growth. Indeed, human GBMs express variable amounts of iNOS.

Methods. In this study, the expression of iNOS and of cytokines known to upregulate IL-1β, tumor necrosis factor—α, interferon-γ or downregulate iNOS transcription (IL-10, transforming growth factor [TGF]β1, and TGFβ2) were measured using reverse transcription—polymerase chain reaction with competitor DNA in 39 samples of human GBM. The iNOS level in GBM was positively correlated with IL-1β messenger (m)RNA, but not with the other cytokines tested. Immunocytochemical double labeling revealed that both anti-iNOS immunoreactivity and anti—IL-1β immunoreactivity colocalized with glial fibrillary acidic protein immunoreactivity in GBM. Some macrophage/microglial cells also expressed iNOS, but not IL-1β. Comparison of biological data with clinical parameters indicated that the survival duration was enhanced when levels of IL-1β mRNA were elevated or when levels of TGFβ2 were low, but was independent of the level of iNOS mRNA within the tumor.

Conclusions. Taken together, these data indicate that the proinflammatory cytokine IL-1β produced within GBM by glial-derived cells has a negative impact on tumor growth through a mechanism independent of iNOS induction.
Far-lateral approach to intradural lesions of the foramen magnum without resection of the occipital condyle
Authors: Nanda Anil , Vincent David A. , Vannemreddy Prasad S. S. V. , Baskaya Mustafa K. , Chanda Amitabha
Published: May 2009

Object. The goal of this study was to determine whether drilling out the occipital condyle facilitates surgery via the far-lateral approach by comparing data from 10 clinical cases with that from studies of eight cadaver heads.

Methods. During the last 6 years at Louisiana State University Health Sciences Center—Shreveport, 10 patients underwent surgery via the far-lateral approach to the foramen magnum. Six of these patients harbored anterior foramen magnum meningiomas, one patient a dermoid cyst, two patients vertebral artery (VA) aneurysms, and an additional patient suffered from rheumatoid disease of the craniocervical junction. The surgical approach consisted of retromastoid craniectomy and C-1 laminectomy.

The seven tumors and the pannus of rheumatoid disease were completely excised, and the two aneurysms were clipped without drilling the occipital condyle. In one patient a chronic subdural hematoma was found 3 months after surgery, but no patient displayed any complication associated with surgery. It is significant that in no patient was a cerebrospinal fluid leak present. All patients experienced improved neurological function postoperatively.

To compare surgical visibility, eight cadaveric specimens (16 sides) were studied, including delineation of the VA and its segments around the craniocervical junction. Increase in visibility as a function of fractional removal of the occipital condyle was quantified by measuring the degrees of visibility gained by removing one third and one half of the occipital condyle. Removal of one third of the occipital condyle produced a mean increase of 15.9° visibility, and removal of one half produced a mean increase of 19.9°.

Conclusions. On the basis of their findings the authors conclude that removal of the occipital condyle is not necessary for the safe and complete resection of anterior intradural foramen magnum tumors.
Superficial surgical landmarks for the frontal sinus
Authors: Tubbs R. Shane , Elton Scott , Salter George , Blount Jeffrey P. , Grabb Paul A. , Oakes W. Jerry
Published: May 2009

Object. There is a lack of reports in the literature that contain descriptions of superficial anatomical landmarks for the identification of the internally located frontal sinus. Neurosurgeons must often enter the cranium through the frontal bone and knowledge of the frontal sinus is essential to minimize complications.

Methods. Seventy adult cadaveric frontal sinuses were evaluated. Measurements included both the lateral and superior extent of the frontal sinus in reference to a midpupillary line, and the superior extent of the frontal sinus from the nasion. Frontal sinuses were found bilaterally in all specimens. The mean height of the frontal sinus superior to the nasion was 2.8 cm. In 71.4% and 74.3% of specimens the lateral extent of the frontal sinus was found to be medial to the left and right midpupillary line, respectively. Distances superior to a plane drawn through the supraorbital ridges at a midpupillary line included a mean of 2.5 mm for the left side and 1.8 mm for the right side.

Conclusions. Of 70 sinuses, none extended more than 5 mm lateral to a midpupillary line. At this same midpupillary line and at a plane drawn through the supraorbital ridges, the frontal sinus was never higher than 12 mm. Finally, in the midline the frontal sinus never reached more than 4 cm above the nasion. These measurements will assist surgeons who must manipulate the frontal bone.
Accuracy of transcranial color Doppler ultrasonography in the diagnosis of middle cerebral artery spasm determined by receiver operating characteristic analysis
Authors: Mariak Zenon , Krejza Jaroslaw , Swiercz Miroslaw , Kordecki Kazimierz , Lewko Janusz
Published: May 2009

Object. The value of transcranial Doppler ultrasonography for the detection of middle cerebral artery (MCA) spasm has been asserted. None of the published studies, however, has adequately scrutinized the overall diagnostic accuracy of this procedure. There are only sporadic reports concerning the utility of transcranial color Doppler (TCCD) ultrasonography, although this method has been proved to be more precise. In this study the authors attempted to estimate the performance of TCCD ultrasonography in detecting MCA narrowing by using receiver operating characteristic (ROC) curve analysis, based on TCCD studies obtained in a relatively large, randomly selected population of patients.

Methods. Transcranial color Doppler ultrasonography studies were obtained in 100 consecutive patients (54 men and 46 women ages 18–74 years, median age 50 years) routinely referred by neurosurgeons for intraarterial angiography. The M1 segment of the MCA was insonated using a 2.5-MHz probe via a temporal acoustic window, and angle-corrected flow velocities were obtained. Angiographically depicted vasospasm was graded as none, mild (≤ 25% vessel caliber reduction), and moderate to severe (> 25% vessel caliber reduction). The effectiveness of TCCD ultrasonography in diagnosing MCA spasm was evaluated by calculating the areas under the ROC curves (Az).

Of the 200 MCAs examined, 173 were successfully visualized with the aid of TCCD ultrasonography. Mild vasospasm was angiographically diagnosed in 15 arteries and moderate-to-severe vasospasm in 28. The best-performing TCCD parameter for the detection of MCA narrowing was revealed to be peak systolic velocity. The Az value for moderate-to-severe vasospasm only was 0.93 and that for all vasospasms was 0.8. The best efficiency, that is, the optimal tradeoff between sensitivity and specificity in diagnosing vasospasms, was associated with a peak systolic velocity of 182 cm/second.

Conclusions. The performance of TCCD ultrasonography in the diagnosis of advanced MCA narrowing is very good, and is acceptable for all vasospasms. The best-performing parameter was peak systolic velocity.
Electromagnetic field hazards involving adjustable shunt valves in hydrocephalus
Authors: Schneider Thomas , Knauff Uwe , Nitsch Jürgen , Firsching Raimund
Published: May 2009

Object. Standard therapy for hydrocephalus involves shunts and valves, which are frequently adjustable. Because of increasing “electromagnetic smog” (for example, that generated by cellular phones), these valves are often exposed to electromagnetic fields.

Methods. Various magnetic fields were tested for their effects on two different kinds of adjustable valves. The minimum magnetic flux density affecting the adjustment of the valve was determined. Results were compared with magnetic fields found in contemporary everyday life.

In homogeneous magnetic fields the adjustment of one valve (Sophysa model SM8) was changed at 5 mT, whereas the second valve (Codman Hakim model CM) was not affected. In nonhomogeneous fields the SM8 valve was affected at 25 mT and the CM valve at 15 mT. Thus, these valves may be affected by headphones and telephone receivers. Surroundings such as the Japanese magnetic suspension railway and the lead cabin of electrical railway engines, in which critical levels of magnetic flux may be present, may also affect adjustable valves. The high-frequency fields of cellular phones, however, have no effect on these valves.

Conclusions. Every surgeon who implants these valves and every patient who receives them should know the possible hazards. The valve selection should be adapted to the environment of the patient. Devices with critical levels of electromagnetic flux that are used in the homes of patients should be replaced by ones with lower magnetic fields. The future construction of these valves should be modified in such a way that their adjustment requires a higher magnetic flux density, so that the valves become less sensitive to unwanted effects from environmental magnetic fields.
Preclinical evaluation of a novel device for delivering brachytherapy to the margins of resected brain tumor cavities
Authors: Stubbs James B. , Frankel Roger H. , Schultz Karl , Crocker Ian , Dillehay Dirck , Olson Jeffrey J.
Published: May 2009

Object. The objectives of this study were to evaluate the safety and performance of a new brachytherapy applicator in the treatment of resected brain tumors in a canine model.

Methods. The brachytherapy applicator is an inflatable balloon catheter that is implanted in the resection cavity remaining after a brain tumor has been debulked. After implantation the balloon is inflated with Iotrex, a sterile solution containing organically bound iodine-125. The low-energy photons emitted by the iodine-125 deposit a therapeutic radiation dose across short distances from the surface of the balloon. After delivery of a prescribed radiation dose to the targeted volume, the radioactive fluid is retrieved and the catheter removed.

Small resections of the right frontal lobe were performed in large dogs. Magnetic resonance (MR) images were obtained and used to assess tissue response and to measure the conformance between the resection cavity wall and the balloon surface. In four animals a dose ranging from 36 to 59 Gy was delivered. Neurological status and histological characteristics of the brain were assessed in all dogs.

Implantation and explantation as well as inflation and deflation of the device were easily accomplished and well tolerated. The device was easily visualized on MR images, which demonstrated the expected postsurgical changes. The resection cavity and the balloon were highly conformal (range 93–100%). Histological changes to the cavity margin were consistent with those associated with surgical trauma. Additionally, radiation-related changes were observed at the margins of the resection cavity in dogs in which the brain was irradiated.

Conclusions. This balloon catheter and 125I radiotherapy solution system can safely and reliably deliver radiation to the margins of brain cavities created by tumor resection. Results of this study showed that intracranial pressure changes due to balloon inflation and deflation were unremarkable and characteristic of the imaging properties and radiation safety profile of the device prior to its clinical evaluation. Clinically relevant brachytherapy (adequate target volume and total dose) was accomplished in all four animals subjected to treatment.