bluuebunny/crossref_metadata_2025_split huggingface dataset:
Xenotime-(Y) veins in a Neoproterozoic metamudstone (Małopolska Block, S Poland)
Authors: Stanisławska Maja , Michalik Marek 
Published: May 2009

Xenotime-(Y) veins in a Neoproterozoic metamudstone (Małopolska Block, S Poland)First occurrence of xenotime-(Y) veins in the Neoproterozoic metamudstone, NW margin of the Małopolska Block, is reported here. The veins are <5 μm thick, inhomogeneous and of varied morphology. Their textural characteristics, exhibiting very low U and Th contents (<1 wt%) and relatively high heavy rare earth elements (REE) contents (12-24 REE2O3 wt%), suggest hydrothermal genesis, though diagenetic precursors of the veins are not excluded. The veins provide good evidence of the mobility of Y, REE, U and Th in low-temperature conditions (anchimetamorphic to greenschist facies). The observed differences in the chemical composition of the veins may indicate multiple stages of formation, possibly during several hydrothermal events that affected the area.
A comparison of hinge craniotomy and decompressive craniectomy for the treatment of malignant intracranial hypertension: early clinical and radiographic analysis
Authors: Kenning Tyler J. , Gandhi Ravi H. , German John W. 
Published: June 2009

Object
Hinge craniotomy (HC) has recently been described as an alternative to decompressive craniectomy (DC). Although HC may obviate the need for cranial reconstruction, an analysis comparing HC to DC has not yet been published.

Methods
A retrospective review was conducted of 50 patients who underwent cranial decompression (20 with HC, 30 with DC). Baseline demographics, neurological examination results, and underlying pathology were reviewed. Clinical outcome was assessed by length of ventilatory support, length of intensive care unit stay, and survival at discharge. Control of intracranial hypertension was assessed by average daily intracranial pressure (ICP) for the duration of ICP monitoring and an ICP therapeutic intensity index. Radiographic outcomes were assessed by comparing preoperative and postoperative CT scans for: 1) Rotterdam score; 2) postoperative volume of cerebral expansion; 3) presence of uncal herniation; 4) intracerebral hemorrhage; and 5) extraaxial hematoma. Postoperative CT scans were analyzed for the size of the craniotomy/craniectomy and magnitude of extracranial herniation.

Results
No significant differences were identified in baseline demographics, neurological examination results, or Rotterdam score between the HC and DC groups. Both HC and DC resulted in adequate control of ICP, as reflected in the average ICP for each group of patients (HC = 12.0 ± 5.6 mm Hg, DC = 12.7 ± 4.4 mm Hg; p > 0.05) at the same average therapeutic intensity index (HC = 1.2 ± 0.3, DC = 1.2 ± 0.4; p > 0.05). The need for reoperation (3 [15%] of 20 patients in the HC group, 3 [10%] of 30 patients in the DC group; p > 0.05), hospital survival (15 [75%] of 20 in the HC group, 21 [70%] of 30 in the DC group; p > 0.05), and mean duration of both mechanical ventilation (9.0 ± 7.2 days in the HC group, 11.7 ± 12.0 days in the DC group; p > 0.05) and intensive care unit stay (11.6 ± 7.7 days in the HC group, 15.6 ± 15.3 days in the DC group; p > 0.05) were similar. The difference in operative time for the two procedures was not statistically significant (130.4 ± 71.9 minutes in the HC group, 124.9 ± 63.3 minutes in the DC group; p > 0.05). The size of the cranial defect was comparable between the 2 groups. Postoperative imaging characteristics, including Rotterdam score, also did not differ significantly. Although a smaller volume of cerebral expansion was associated with HC (77.5 ± 54.1 ml) than DC (105.1 ± 65.1 ml), this difference was not statistically significant.

Conclusions
Hinge craniotomy appears to be at least as good as DC in providing postoperative ICP control and results in equivalent early clinical outcomes.
Crossed-screw fixation of the unstable thoracic and lumbar spine
Authors: Benzel Edward C. , Baldwin Nevan G. 
Published: June 2009

✓ An ideal spinal construct should immobilize only the unstable spinal segments, and thus only the segments fused. Pedicle fixation techniques have provided operative stabilization with the instrumentation of a minimal number of spinal segments; however, some failures have been observed with pedicle instrumentation. These failures are primarily related to excessive preload forces and limitations caused by the size and orientation of the pedicles.
To circumvent these problems, a new technique, the crossed-screw fixation method, was developed and is described in this report. This technique facilitates short-segment spinal fixation and uses a lateral extracavitary approach, which provides generous exposure for spinal decompression and interbody fusion. The technique employs two large transverse vertebral body screws (6.5 to 8.5 mm in diameter) to bear axial loads, and two unilateral pedicle screws (placed on the side of the exposure) to restrict flexion and extension deformation around the transverse screws and to provide three-dimensional deformity correction. The horizontal vertebral body and the pedicle screws are connected to rods and then to each other via rigid crosslinking. The transverse vertebral body screws are unloaded during insertion by placing the construct in a compression mode after the interbody bone graft is placed, thus optimizing the advantage gained by the significant “toe-in” configuration provided and further decreasing the chance for instrumentation failure.
The initial results of this technique are reported in a series of 10 consecutively treated patients, in whom correction of the deformity was facilitated. Follow-up examination (average 10.1 months after surgery) demonstrated negligible angulation. Chronic pain was minimal. The crossed-screw fixation technique is biomechanically sound and offers a rapid and safe form of short-segment three-dimensional deformity correction and solid fixation when utilized in conjunction with the lateral extracavitary approach to the unstable thoracic and lumbar spine. This approach also facilitates the secure placement of an interbody bone graft.
Transmaxillosphenoidal approach to tumors invading the medial compartment of the cavernous sinus
Authors: Fraioli Bernardo , Esposito Vincenzo , Santoro Antonio , Iannetti Giorgio , Giuffrè Renato , Cantore Gianpaolo 
Published: June 2009

✓ A transmaxillosphenoidal approach was used to remove sellar tumors invading the cavernous sinus. This procedure, a widening of the standard transsphenoidal approach to the sella turcica, uses the sublabial or transnasal route in which the medial wall of the maxillary sinus is laterally dislocated. This method provides good exposure of the prominences of bone above the carotid artery which lies on the posterolateral wall of the sphenoid sinus. This bone area is the key to opening the cavernous sinus inferomedially and removing lesions within its medial compartment.
The inferomedial approach takes an entirely extracerebral route so that tumors invading the cavernous sinus through its medial wall are approached inferomedially following the direction of tumor growth. It also allows direct visualization of the intracavernous carotid artery during tumor removal, thus sparing the cranial nerves, which run on the opposite side. Adequate surgical exposure of a pituitary adenoma is achieved with a custom-made sphenoidal retractor with asymmetric blades, the shorter blade holding aside the thin medial wall of the maxillary sinus.
Between October, 1989, and July, 1993, 11 patients with tumors invading the cavernous sinus underwent surgery via this approach; 10 had pituitary adenomas and one had a craniopharyngioma. Eight tumors were treated by primary operation: four tumors were totally and four subtotally (> 80%) removed; one tumor already operated on elsewhere was totally removed; and of two tumors already operated on and irradiated, one was subtotally removed and the other only partially (approximately 40%) removed owing to marked postirradiation scarring. None of the patients suffered permanent cranial nerve deficit and all but one showed marked clinical improvement.
Microvascular anatomy of the anterior surface of the medulla oblongata and olive
Authors: Akar Ziya C. , Dujovny Manuel , Gómez-Tortosa Estrella , Slavin Konstantin V. , Ausman James I. 
Published: June 2009

✓ The arterial supply and the microanatomy of the anterior surface of the medulla oblongata and olive were studied in 11 cadaveric specimens, with investigation of the size, course, and length of the arteries. Two distinct anatomical entities divide the vascular supply in this region: 1) the pyramid, which is the anterior surface of the medulla; and 2) the olive, which is adjacent to the lateral aspect of the pyramid. Primary vascularization of the pyramid was via small branches of the anterior spinal artery, a branch of the vertebral artery. Minute perforators from the anterior spinal artery were found in all specimens. Arterial supply to the olive varied by location: its anterior aspect was primarily supplied by the anterior spinal artery; the upper portion of the posterior aspect of the olive was supplied by the vertebral artery, the anterior inferior cerebellar artery, and the basilar artery; and the middle and lower portions of the posterior aspect were fed by the vertebral artery and posterior inferior cerebellar artery. These arteries supplied the medulla through the small branches directed toward the olive.
The authors observed a wide anastomotic net connecting the small arteries in this area. These patterns of microvascular supply of the pyramid and olive may deepen the understanding of clinical and pathological conditions resulting from arterial occlusion. The existence of an anastomotic net may account for the rare incidence of medullary infarction in the olive region.
Linear accelerator radiosurgery for arteriovenous malformations: the relationship of size to outcome
Authors: Friedman William A. , Bova Frank J. , Mendenhall William M. 
Published: June 2009

✓ Between May, 1988 and August, 1993, 158 patients with arteriovenous malformations (AVMs) were treated radiosurgically at the University of Florida. A mean dose of 1560 cGy was directed to the periphery of the lesions, which had a mean volume of 9 cc (0.5 to 45.3 cc). One hundred thirty-nine of these individuals were treated with one isocenter. The mean follow-up interval was 33 months with clinical information available on 153 of these patients. Patients were followed until magnetic resonance (MR) studies suggested complete AVM thrombosis. An arteriogram was then performed, if possible, to verify occlusion status. If arteriography revealed any persistent nidus at 36 months posttreatment, the residual nidus was re-treated.
Outcome categories of AVMs analyzed included the following possibilities: 1) angiographic cure; 2) angiographic failure; 3) re-treatment; 4) MR image suggested cure; 5) MR image suggested failure; 6) patient refused follow-up evaluation; 7) patient lost to follow-up study; or 8) patient deceased. The endpoints for success or failure of radiosurgery were as follows: angiographic occlusion (success), re-treatment (failure), and death due to AVM hemorrhage (failure). Fifty-six patients in this series reached one of the endpoints. Successful endpoints were seen in 91% of AVMs between 1 and 4 cc in volume, 100% of AVMs 4 to 10 cc in volume, and 79% of AVMs greater than 10 cc in volume.
The more traditional measure of radiosurgical success, percentage of angiograms showing complete obliteration, was obtained in 81% of AVMs between 1 and 4 cc in volume, 89% of AVMs between 4 and 10 cc in volume, and 69% of AVMs greater than 10 cc in volume. A detailed analysis of the relationship of all outcome categories to size is presented.
The use of intraarterial papaverine in the management of vasospasm complicating arteriovenous malformation resection
Authors: Morgan Michael K. , Day Maurice J. , Little Nicholas , Grinnell Verity , Sorby William 
Published: June 2009

✓ The authors report two cases of treatment by intraarterial papaverine of cerebral vasospasm complicating the resection of an arteriovenous malformation (AVM). Both cases had successful reversal of vasospasm documented on angiography. In the first case sustained neurological improvement occurred, resulting in a normal outcome by the time of discharge. In the second case, neurological deterioration occurred with the development of cerebral edema. This complication was thought to be due to normal perfusion pressure breakthrough, on the basis of angiographic arterial vasodilation and increased cerebral blood flow.
These two cases illustrate an unusual complication of surgery for AVMs and demonstrate that vasospasm (along with intracranial hemorrhage, venous occlusion, and normal perfusion pressure breakthrough) should be considered in the differential diagnosis of delayed neurological deterioration following resection of these lesions. Although intraarterial papaverine may be successful in dilating spastic arteries, it may also result in pathologically high flows following AVM resection. However, this complication has not been seen in our experience of treating aneurysmal subarachnoid hemorrhage by this technique.
Cerebrovascular carbon dioxide reactivity assessed by intracranial pressure dynamics in severely head injured patients
Authors: Yoshihara Masaaki , Bandoh Kuniaki , Marmarou Anthony 
Published: June 2009

✓ Appropriate management of intracranial pressure (ICP) in severely head injured patients depends in part on the cerebral vessel reactivity to PCO2; loss of CO2 reactivity has been associated with poor outcome. This study describes a new method for evaluating vascular reactivity in head-injured patients by determining the sensitivity of ICP change to alterations in PCO2. This method was combined with measurements of the pressure volume index (PVI), which allowed calculation of blood volume change necessary to alter ICP. The objective of this study was to investigate the ICP response and the blood volume change corresponding to alterations in PCO2 and to examine the correlation of responsivity and outcome as measured on the Glasgow Outcome Scale.
The PVI and ICP at different end-tidal PCO2 levels produced by mild hypo- and hyperventilation were obtained in 49 patients with Glasgow Coma Scale scores of less than 8 and over a wide range of PCO2 (25 to 40 mm Hg) in eight patients. Given the assumption that the PVI remained constant during alteration of PaCO2, the estimated blood volume change per torr change of PCO2 was calculated by the following equation: BVR = PVI × Δlog(ICP)/ΔPCO2, where BVR = blood volume reactivity. The data in this study showed that PVI remained stable with changes in PCO2, thus validating the assumption used in the blood volume estimates. Moreover, the response of ICP to PCO2 alterations followed an exponential curve that could be described in terms of the responsivity indices to capnic stimuli. It was found that responsivity to hypocapnia was reduced by 50% compared to responsivity to hypercapnia measured within 24 hours of injury (p < 0.01). The sensitivity of ICP to estimated blood volume changes in patients with a PVI of less than 15 ml was extremely high with only 4 ml of blood required to raise ICP by 10 mm Hg. The authors conclude from these data that, following traumatic injury, the resistance vessels are in a state of persistent vasoconstriction, possibly due to vasospasm or compression. Furthermore, BVR correlates with outcome on the Glasgow Coma Scale, indicating that assessment of cerebrovascular response within the first 24 hours of injury may be of prognostic value.
Continuous intraoperative electromyographic recording during spinal surgery
Authors: Beatty Robert M. , McGuire Peggy , Moroney Jean M. , Holladay Frank P. 
Published: June 2009

✓ One hundred fifty patients underwent spinal surgery for radiculopathy; of these, 120 underwent lumbar surgery and 30 had cervical operations. All of the surgeries were performed to alleviate symptoms due to disc herniation, spondylosis, or both. During the surgical procedures continuous intraoperative electromyograph recordings were taken from the muscle corresponding to the involved nerve root. In baseline recordings taken in the operating room 10 minutes before lumbar surgery, electrical discharge or firing was recorded from the muscle in 18% (22 of 120 patients) of the cases. Once the nerve was decompressed, muscle firing ceased. Electrical discharges were produced with regularity on nerve root retraction.This study concludes that continuous electromyograph monitoring can be accomplished easily and yields valuable information that indicates when the nerve root is adequately decompressed or when undue retraction is exerted on the root.
Interstitial radiosurgery of low-grade gliomas
Authors: Kreth Friedrich W. , Faist Michael , Warnke Peter C. , Roβner Reinhard , Volk Benedikt , Ostertag Christoph B. 
Published: June 2009

✓ The treatment of patients with low-grade gliomas remains a subject of controversy, especially with respect to new treatment modalities such as interstitial radiosurgery (brachytherapy), radiosurgery, and stereotactic radiotherapy. In a retrospective analysis conducted between 1979 and 1991, the authors studied the results of interstitial radiosurgery in 455 patients with low-grade gliomas (World Health Organization (WHO) Grade I + WHO Grade II) with regard to survival time, quality of life, the risk of malignant transformation, and the risk profile of the treatment concept. Interstitial radiosurgery with iodine-125 was performed using permanent (1979–1985) or temporary implants (after 1985) with low-dose rates (≤ 10 cGy/hr) and a reference dose of 60 to 100 Gy calculated to the outer rim of the tumor.The 5- and 10-year survival rates in patients with pilocytic astrocytomas (97 patients) were 84.9% and 83%, and in patients with WHO Grade II astrocytomas (250 patients) 61% and 51%, respectively. Five-year survival rates for patients with oligoastrocytomas (60 patients), oligodendrogliomas (27 patients), and gemistocytic astrocytomas (21 patients) were 49%, 50%, and 32%, respectively. In the group with WHO Grade II gliomas, young age and a good performance status were associated with a better prognosis. Unfavorable factors were midline shift, enhancement on computerized tomography (CT) scan, and tumor recurrence after previous radiotherapy or surgery. Tumor location had no influence on the prognosis (247 patients in this series had deep-seated tumors). Malignant transformation was the major cause of death. Important risk factors for malignancy were the patient's age, tumor enhancement in CT scan, and tumor recurrence after previous surgery or radiotherapy. Perioperative mortality was 0.9% and perioperative morbidity was 1.7%. Radiogenic complications were observed in 2.7% of all patients, most often in larger tumors and after using permanent implants. The authors conclude that interstitial radiosurgery represents a specific treatment modality for selected patients with unifocal circumscribed low-grade gliomas with a diameter of less than 4 cm in any location. The efficacy of this treatment lies in the same range as the best results after surgery and radiotherapy.
Isolated toxoplasmosis of the thoracic spinal cord in a patient with acquired immunodeficiency syndrome
Authors: Resnick Daniel K. , Comey Christopher H. , Welch William C. , Martinez A. Julio , Hoover William W. , Jacobs George B. 
Published: June 2009

✓ Toxoplasmosis and lymphoma are the two most common causes of intraparenchymal cerebral mass lesions in patients with acquired immunodeficiency syndrome (AIDS). The clinical and radiographic features of the intracranial lesions have been well described. Because of the high frequency of toxoplasmosis in the AIDS population, common therapy for patients presenting with intracranial mass lesions consists of an empirical trial of anti-Toxoplasma chemotherapy, with biopsy reserved for cases demonstrating features considered to be more consistent with lymphoma, or for lesions that do not improve despite adequate anti-Toxoplasma treatment. A similar treatment algorithm does not exist for intramedullary lesions of the spinal cord.
The authors describe a patient who presented with paraparesis resulting from an isolated thoracic intramedullary lesion. An open biopsy of the lesion revealed characteristic structures containing Toxoplasma tachyzoites. The clinical and radiographic presentation of the lesion is discussed, the available literature is reviewed, and a treatment strategy for spinal cord lesions in AIDS patients is proposed.
Surgical treatment of jugular foramen schwannomas
Authors: Samii Madjid , Babu Ramesh P. , Tatagiba Marcos , Sepehrnia Abolghassem 
Published: June 2009

✓ Sixteen patients with schwannomas of the jugular foramen were operated on in the Department of Neurosurgery of the Nordstadt Hospital in Hannover, Germany, between 1986 and 1992. Patients with neurofibromatosis were excluded. The records of the 16 patients were retrospectively reviewed. There were five women and 11 men (mean age 43 years) with a symptom duration ranging from 6 months to 20 years (mean 5 years). The predominant symptoms were hearing loss, hoarseness, and cerebellar symptoms. Computerized tomography (CT), magnetic resonance (MR) imaging, and angiography were performed in all 16 patients. Depending on the radiological and surgical features, the tumors were classified into four types: Type A, a tumor primarily at the cerebellopontine angle with minimal enlargement of the jugular foramen (eight cases); Type B, a tumor primarily at the jugular foramen with intracranial extension (two cases); Type C, a primarily extracranial tumor with extension into the jugular foramen (one case); and Type D, a dumbbell-shaped tumor with both intra- and extracranial components (five cases).
A retromastoid suboccipital craniectomy was performed for Type A tumors, and a combined cervical-mastoidectomy for Types B, C, and D. Total tumor removal was achieved in all cases. There was no operative mortality. Postoperative complications were cerebrospinal fluid leakage in one patient and mastoiditis in two patients. The follow-up period ranged from 12 to 42 months (mean 22 months). All patients were alive at the last follow-up review, and CT and/or MR imaging showed no tumor recurrence.
Validation of transcranial Doppler ultrasound with a stereotactic neurosurgical technique
Authors: Monsein Lee H. , Razumovsky Alex Y. , Ackerman Stacey J. , Nauta Haring J. W. , Hanley Daniel F. 
Published: June 2009

✓ Vessel identification during a transcranial Doppler (TCD) ultrasound examination is usually based on well-established inferential criteria without confirmation by imaging. Part of a routine study involves taking measurements from the M1 segment of the middle cerebral artery (MCA) and the A1 segment of the anterior cerebral artery (ACA) at the points of maximum mean linear blood flow velocity (LBFV). The authors tested the hypothesis that insonation is from the midpoints of the M1 and A1 segments during clinical TCD examinations.
Conventional hand-held TCD examinations were performed on five volunteers. The points of maximum mean LBFV of the M1 and A1 segments of the MCA and ACA were located. Measurements were also taken from the midpoints of the M1 and A1 segments using a magnetic resonance (MR) imaging-guided stereotactic TCD technique. Values for depths of insonation and maximum mean LBFV obtained with the two techniques were compared. There was no significant difference between the two techniques for the measured values of depth of insonation of either the individual vessels (p > 0.11) or the aggregate (p = 0.46). There was a significant difference between the aggregate maximum mean LBFV measurements (p = 0.0022). The hand-held technique systematically produced higher maximum mean LBFV than the MR-guided stereotactic technique. The authors conclude that when using traditional criteria for TCD examination of the ACA and MCA, the points of insonation approximate the middle of the A1 and M1 segments.