bluuebunny/crossref_metadata_2025 huggingface dataset:
Attenuation of postischemic brain hypoperfusion and reperfusion injury by the cyclooxygenase—lipoxygenase inhibitor BW755C
Authors: Chen Jun , Weinstein Philip R. , Graham Steven H.
Published: June 2009

✓ Arachidonic acid metabolites are believed to be important mediators of tissue injury during reperfusion after cerebral ischemia. To determine whether inhibiting the oxygen-dependent metabolism of arachidonic acid would reduce reperfusion injury, we administered the mixed cyclooxygenase—lipoxygenase inhibitor BW755C (3-amino-1-[m(trifluoromethyl) phenyl]-2-pyrazoline) near the time of reperfusion in a rat model of temporary focal ischemia. The duration of ischemia + reperfusion was 2 hours + 22 hours, 3 hours + 3 hours, or 3 hours + 21 hours. The effects of drug or saline treatment on infarct volume, blood-brain barrier permeability, and blood flow were determined. Cortical blood flow was monitored with laser Doppler flowmetry and blood-brain barrier permeability was evaluated by the Evans blue dye method. Infarct volume was determined in all groups by computerized image analysis of Nissl-stained sections. We found that BW755C treatment significantly attenuated delayed postischemic hypoperfusion in the 3 + 3 group (p < 0.05) and reduced the volume of Evans blue dye staining in the cortex (p < 0.01) and basal ganglia (p < 0.05). Hemispheric swelling was reduced in all treatment groups (p < 0.01), as was total infarct volume in the ischemic hemisphere (p < 0.05). These results support the hypothesis that arachidonic acid metabolites contribute to acute postischemic reperfusion injury and suggest that using a mixed cyclooxygenase—lipoxygenase inhibitor as an adjunct to thrombolytic or revascularization therapy could lengthen the ischemia time after which reperfusion is beneficial.
Synergistic effect of basic fibroblast growth factor and methylprednisolone on neurological function after experimental spinal cord injury
Authors: Baffour Richard , Achanta Kranthi , Kaufman Jeffrey , Berman Joel , Garb Jane L. , Rhee Sang , Friedmann Paul
Published: June 2009

✓ The authors evaluated the effects of exogenous basic fibroblast growth factor (bFGF) in combination with intravenous methylprednisolone on neurological function and cord angiogenesis in a model of spinal cord injury. Cord injury was produced by extradural clip compression through a T-1 laminectomy. Rats were randomized to one of six groups. Group A was given sham laminectomy without cord injury or treatment. The remaining animals were divided into five groups: untreated injury (Group B); injury treated with methylprednisolone (Group C); combined methylprednisolone and 1 µ bFGF administered locally at the site of injury (Group D); methylprednisolone and 3 µg bFGF (Group E); or methylprednisolone and 3 µg heated bFGF (Group F). Groups C through F received treatment 1 hour after cord injury. At 1, 2, 3, and 4 weeks after surgery, neurological function of hindlimbs was assessed by blinded observers using an established multiple test method (toe spread, reflexes to extension, pain, and pressure as well as inclined plane and swim test) with tests graded and results expressed as a combined behavioral score. Animals were killed to study spinal cord angiogenesis in cord samples (2-mm sections proximal and distal to the injury site) by capillary density determination. Behavioral scores over time showed a significant difference among Groups B, C, D, E, and F (p = 0.0044), with Groups E and B maintaining highest and lowest scores, respectively. There was a linear dose effect of bFGF over time (p = 0.0187). At 4 weeks, scores showed a difference among the five groups (p = 0.006), with Group E showing higher scores than any other treatment group (for example, vs. group F: p = 0.035). There was a significant difference among the groups in gray matter capillary density counts: proximal (p = 0.0192) and distal (p = 0.024), whereas white matter capillary counts were similar across treatment groups. These results show: 1) possible synergism exists between methylprednisolone and bFGF, such that combinations of these drugs significantly enhance neurological recovery, 2) bFGF exhibits a dose—response effect in function but not in capillary density, and 3) heated, inactivated bFGF is not therapeutically effective.
Pathological effects of angioplasty on vasospastic carotid arteries in a rabbit model
Authors: Macdonald R. Loch , Wallace M. Christopher , Montanera Walter J. , Glen Jennifer A.
Published: June 2009

✓ To define the pathological effects of angioplasty on vasospastic arteries, 36 rabbits underwent angiography and induction of vasospasm by placement of blood-filled (vasospasm groups) or empty (control group) silastic sheaths around the cervical carotid arteries. Two (Day 2) or 7 days (Day 7) later, angiography was repeated and one carotid artery in each animal was dilated by balloon angioplasty. The rabbits were sacrificed 1 day, 7 days, or 3 to 4 weeks after angioplasty. Significant vasospasm developed after placement of silastic sheaths with blood (mean reductions in diameter 39% ± 6% at Day 2 and 48% ± 5% at Day 7). Arterial narrowing was less apparent in the control groups at Day 2 (24% ± 7%). Angioplasty performed on Day 2 significantly increased arterial diameters of vasospastic arteries (50% ± 7%; p < 0.05) but not those of control arteries (10% ± 6%, p > 0.05). Angioplasty performed on Day 7 increased the arterial diameters by a similar degree (47% ± 13%, not significant). Arteries remained dilated after angioplasty, although there was significant vasospasm 7 days after angioplasty when angioplasty was performed on Day 2. Blinded, semiquantitative histopathological study of the arteries showed that 3 to 4 weeks after angioplasty, there was significant endothelial proliferation and a trend for thinning of the tunica media. There were no significant changes in control arteries subjected to angioplasty. Angioplasty was not associated with significant arterial fibrosis as measured by hydroxyproline content (analysis of variance). The increase in endothelial proliferation and decrease in the thickness of the tunica media suggest that, in the rabbit model, angioplasty damages endothelial and smooth-muscle cells. This may be the basis for the observation that vasospastic arteries do not reconstrict after angioplasty.
Effect of intracarotid nitric oxide on primate cerebral vasospasm after subarachnoid hemorrhage
Authors: Afshar John K. B. , Pluta Ryszard M. , Boock Robert J. , Thompson B. Gregory , Oldfield Edward H.
Published: June 2009

✓ The continuous release of nitric oxide (NO) is required to maintain basal cerebrovascular tone. Oxyhemoglobin, a putative spasmogen, rapidly binds NO, implicating loss of NO in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). If vasospasm is mediated by depletion of NO in the vessel wall, it should be reversible by replacement with NO. To investigate this hypothesis, the authors placed blood clots around the right middle cerebral artery (RMCA) of four cynomolgus monkeys; four unoperated animals served as controls. Arteriography was performed before and 7 days after surgery to assess the presence and degree of vasospasm, which was quantified in the anteroposterior (AP) projection by computerized image analysis. On Day 7, cortical cerebral blood flow (CBF) in the distribution of the right MCA was measured during four to six runs in the right internal carotid artery (ICA) of brief infusions of saline followed by NO solution. Arteriography was performed immediately after completing the final NO infusion in three of the four animals with vasospasm. Right MCA blood flow velocities were obtained using transcranial Doppler before, during, and after NO infusion in two vasospastic animals.

After ICA NO infusion, arteriographic vasospasm resolved (mean percent of preoperative AP area, 55.9%); that is, the AP areas of the proximal portion of the right MCA returned to their preoperative values (mean 91.4%; range 88%–96%). Compared to ICA saline, during ICA NO infusion CBF increased 7% in control animals and 19% in vasospastic animals (p < 0.002) without significant changes in other physiological parameters. During NO infusion, peak systolic right MCA CBF velocity decreased (130 to 109 cm/sec and 116 to 76 cm/sec) in two vasospastic animals. The effects of ICA NO on CBF and CBF velocity disappeared shortly after terminating NO infusion.

Intracarotid infusion of NO in a primate model of vasospasm 1) increases CBF, 2) decreases cerebral vascular resistance, 3) reverses arteriographic vasospasm, and 4) decreases CBF velocity in the vasospastic artery without producing systemic hypotension. These findings indicate the potential for the development of targeted therapy to reverse cerebral vasospasm after SAH.
Effects of potassium channel activators on isolated cerebral arteries of large and small diameter in the cat
Authors: Schilling Lothar , Parsons Andrew A. , Wahl Michael
Published: June 2009

✓ The smooth-muscle relaxant action of adenosine 5′-triphosphate (ATP)-sensitive potassium (KATP) channels in cerebral arteries of large diameter has been confirmed in a number ofin vitrostudies, but there is still debate about the presence of KATPchannels in small cerebral arteries. In the present study, the authors compare the effects of cromakalim and bimakalim, two putative KATPchannel activators, in different parts of the feline isolated middle cerebral artery (MCA) designated proximal, intermediate, and distal. The latter corresponds to those small pial arteries that are usually studiedin vivo. In ring segments precontracted with 10−5M of uridine-5-triphosphate (UTP), both cromakalim and bimakalim induced concentration-related relaxation, with bimakalim being more potent than cromakalim, and no significant differences noted among segments obtained from the different regions of the MCA. In vessels precontracted by adding 30 mM KCl the potency of cromakalim and bimakalim was reduced compared with that obtained after UTP precontraction. In the presence of 10−6M glibenclamide, an antagonist of KATPchannel activators, the concentration—effect curve to bimakalim was shifted to the right in the proximal and distal MCA, indicating a similar route of action for bimakalim and cromakalim in these arteries. The present study therefore indicates the presence of KATPchannels in isolated small cerebral arteries according to results obtainedin vivo. Activators of KATPchannels may prove helpful in the treatment of vasospasm, which may occur in large and small cerebral arteries after subarachnoid hemorrhage.
Imaging studies of cerebral hyperperfusion after carotid endarterectomy
Authors: Penn Anna A. , Schomer Don F. , Steinberg Gary K.
Published: June 2009

✓ A case is reported of severe unilateral hemispheric edema and localized hemorrhage associated with seizures following endarterectomy of an ipsilateral high-grade carotid stenosis. Imaging studies including angiography, computerized tomography (CT), magnetic resonance imaging/angiography, and xenon-CT, suggested postoperative ipsilateral cerebral hyperperfusion. Cerebral hyperperfusion syndromes caused by a probable failure of vascular autoregulation are rare but potentially serious complications after endarterectomy. The literature on this type of complication is briefly reviewed, and the role of various imaging modalities in identification of the syndrome and in guiding management decisions is emphasized.
Radiation-induced gliosarcoma
Authors: Kaschten Bruno , Flandroy Pierre , Reznik Michel , Hainaut Hadelin , Stevenaert Achille
Published: June 2009

✓ A 13-year-old boy presented with a cerebral gliosarcoma 12 years after having acute lymphoblastic leukemia treated by chemotherapy and central nervous system prophylaxis treated by radiation therapy (24 Gy) and intrathecal methotrexate. A review of the literature disclosed 129 possible radiation-induced gliomatous and/or sarcomatous brain tumors: namely, 89 gliomas, 36 sarcomas, and four gliosarcomas, including the present case. An analysis of these cases revealed several characteristics that differentiate them from similar spontaneous brain tumors, thus providing arguments for the carcinogenic effect of radiation therapy on intracranial tumors.
Crossroads at Salerno: Eldridge Campbell and the writings of Teodorico Borgognoni on wound healing
Authors: Popp A. John
Published: June 2009

✓ During Eldridge Campbell's tour of duty as the neurosurgical consultant to the Mediterranean theater of World War II operations, he was introduced to a then-revolutionary method of wound treatment. Ironically, Campbell's diligent research efforts later revealed that this method of wound treatment had first been advocated seven centuries earlier—in the same geographical location—by the Italian surgeon Theodoric. Although controversial, this method of wound care was subsequently applied and supported by Theodoric's outspoken pupil, Henri de Mondeville, despite intense opposition from the prevailing medical authorities who supported the doctrine of “laudable pus” for wound management. With Mondeville's death, Theodoric's technique lapsed into obscurity, relegated to a historical footnote until modern biology and the discoveries of Lister and Pasteur would again bring to light the benefits of nonsuppurative wound treatment.

In this article the author discusses the work of Theodoric, Mondeville, and Campbell in light of the medical climate of their times and explores the contemporary parallels noted by Campbell in terms of the neglect of other, more recent medical discoveries. These examples encourage us to accept or reject medical treatments based on a thorough examination of their efficacy and not on the stature of their advocates within the medical community.
Hearing preservation in vestibular schwannoma surgery: what factors influence outcome?
Authors: Post Kalmon D. , Eisenberg Mark B. , Catalano Peter J.
Published: June 2009

✓ The goals in the management of patients with vestibular schwannomas have changed drastically over the past few decades, with preservation of useful hearing representing the newest challenge. The true incidence of preserved useful hearing, however, has become clouded by a lack of uniformity in reporting results. The authors have analyzed 56 consecutive cases, in which directed attempts were made to preserve hearing on the involved side, to understand what factors play a major role in postoperative hearing preservation. Of the 56 cases reviewed, there were 46 patients who had “good” preoperative hearing (pure tone average < 50 dB; speech discrimination score > 50%). We found that, in this group of patients, if the tumor was less than 2 cm in diameter from pons to petrous, there was a 52% (16 of 31 patients) chance of preserving good hearing and if the tumor was 1 cm or less, the chances increased to 83%. Factors such as preoperative hearing status, tumor size and location, tumor consistency, and preoperative and intraoperative brainstem auditory evoked potentials are discussed in detail as they relate to postoperative outcome.
Clinical use of a frameless stereotactic arm: results of 325 cases
Authors: Golfinos John G. , Fitzpatrick Brian C. , Smith Lawrence R. , Spetzler Robert F.
Published: June 2009

✓ The viewing wand is a frameless stereotactic arm that can be used in conjunction with computerized tomography (CT) or magnetic resonance (MR) imaging to provide image-based intraoperative navigation. The authors report a series of 325 cases in which the viewing wand was used and evaluated for its utility, ease of integration into the standard surgical setup, reliability, and real-world accuracy. The use of the system was associated with minimal additional effort or time spent in setting up the procedure as long as a trained technician performed the data transfer and reconstruction. The viewing wand was used in 165 cases in conjunction with CT and 145 cases with MR imaging. The system was reliable, achieving a useful registration in 310 of 325 cases (95.4%). Fiducial-based registration was more accurate than an anatomical landmark—surface fit algorithm method of registration (mean 2.8 vs. 5.6 mm error, respectively, for CT; and mean 3.0 vs. 6.2 mm for MR imaging). The actual error of the system in estimating the position of the probe tip just after registration was judged by the operating surgeon to be less than 2 mm in 92% of MR imaging cases and in 82% of CT cases, between 2 and 5 mm in 7% of MR imaging and 17% of CT cases, and greater than 5 mm in less than 1% of MR imaging and 1.2% of CT cases. The accuracy of the system degraded during the operation, so that by the third evaluation the error was estimated to be less than 2 mm in 77% of MR imaging and 62% of CT cases.

Overall, the viewing wand was found to be reliable and accurate. This real-world accuracy was sufficient for a broad range of applications including glioma resection, cerebrospinal fluid shunting procedures, resection of small subcortical masses, and temporal lobe resection. The system is a useful navigational aid that allows a direct approach to intracranial pathology without the drawbacks of application and the limitations of a stereotactic frame.
The natural history and growth rate of asymptomatic meningiomas: a review of 60 patients
Authors: Olivero William C. , Lister J. Richard , Elwood Patrick W.
Published: June 2009

✓ Little is known about the natural history and growth rate of asymptomatic meningiomas. To better delineate this problem, the authors reviewed the clinical records and imaging studies of the last 60 patients diagnosed with asymptomatic meningiomas at their institution. There were 45 women and 15 men, whose ages ranged from 38 to 84 years, with a mean age of 66 years. The most common tumor location was convexity (25 patients), but virtually all locations were represented. Three patients were lost to follow up. The average clinical follow-up review of the remaining 57 patients was 32 months (range 6 months to 15 years). None of the patients became symptomatic from an enlarging tumor during their follow-up period. Typically, once a meningioma was diagnosed, follow-up scans were obtained at 3 months, 9 months, and then yearly or every other year thereafter. Forty-five patients underwent follow-up scans, with comparison of tumor size to that found on the initial scan, over a period ranging from 3 months to 15 years. Thirty-five patients have shown no growth in their tumor size, with an average imaging follow up of 29 months (range 3–72 months). Ten patients have shown tumor growth calculated as an increase in the maximum diameter of the tumor. This growth ranged from 0.2 cm over 180 months to 1 cm over 12 months, with an average of 0.24 cm per year. Average imaging follow up for these patients was 47 months (range 6 months to 15 years).

The authors conclude that patients with asymptomatic meningiomas need close clinical and radiological follow up to rule out other disease processes and to rule out rapidly enlarging tumors. Although the average follow-up time was short, the vast majority of these tumors appeared to show minimal or no growth over periods of time measured in years. With modern noninvasive imaging techniques, these tumors can be safely observed until they enlarge significantly or become symptomatic.
Intraoperative ultrasound-directed resection of pituitary tumors
Authors: Ram Zvi , Shawker Thomas H. , Bradford Mary H. , Doppman John L. , Oldfield Edward H.
Published: June 2009

✓ Microadenomas of the pituitary vary in size, particularly those related to Cushing's disease. They are often not visualized on preoperative magnetic resonance (MR) imaging and may be difficult to find during surgical exploration of the pituitary. To enhance intraoperative localization of pituitary adenomas, we assessed the feasibility of using ultrasound to detect and localize pituitary tumors. Intraoperative ultrasound (IS) in the axial and sagittal planes was performed with an Intrascan system using a 12-MHz mechanically oscillating, end-firing transducer. Interpretation of the scans was performed by two individuals, who were usually blinded to the results of preoperative MR imaging or petrosal sinus sampling.

Twenty-eight patients were examined. Eighteen of these patients had microadenomas (1.5–7 mm), all with Cushing's disease; nine had macroadenomas (10–20 mm), three of which were adrenocorticotropic hormone—secreting, three growth hormone—secreting, two thyroid-stimulating hormone—secreting, and one nonfunctioning; and one patient had an intrasellar craniopharyngioma. Normal sellar and parasellar structures, such as intrapituitary cysts, the intracavernous carotid arteries, and the diaphragma sella were easily visualized. Twenty-three of the 28 tumors, including 13 of the 18 microadenomas, were detected on IS (82% sensitivity). Tumors were seen as hyperechoic masses in 19 patients, mixed echogenicity in three, and isoechoic in one. In most macroadenomas IS allowed visualization of the interface between the tumor and the normal pituitary gland. These results indicate the potential of IS to aid the intraoperative localization and definition of pituitary tumors.
Seizure outcome after lesionectomy for cavernous malformations
Authors: Cohen Douglas S. , Zubay Geoffrey P. , Goodman Robert R.
Published: June 2009

✓ Cavernous malformations that are associated with seizures are often treated by surgical resection consisting of lesion removal, “lesionectomy,” alone. Through retrospective analysis the authors have examined some factors that may predict failure to eradicate seizures by such a procedure. A group of 51 patients were examined who had been treated for supratentorial cavernous malformations with preoperative seizures and received postoperative follow up lasting at least 1 year. There was one mortality in the group. Of the remaining 50 patients, 15 (30%) had continued postoperative seizures despite therapeutic levels of antiepileptic medications. Variables that were significantly associated with continued seizures postoperatively included increasing duration of preoperative seizure history (p = 0.03), increasing number of preoperative seizures (p < 0.003), and female sex (p < 0.04). One hundred percent of patients with only one preoperative seizure or a seizure history lasting less than 2 months were seizure free following lesionectomy: approximately 75% to 80% of all patients with two to five seizures, or a seizure history lasting 2 to 12 months, were seizure free; and only 50% to 55% of those with more than five seizures or with preoperative seizure histories lasting more than 1 year were seizure free postoperatively. This investigation indicates that patients with shorter seizure histories and fewer preoperative seizures can be effectively treated by lesionectomy alone, whereas those with longer histories and more seizures are not effectively treated by this procedure and may require more extensive resections.
Surgical management of atlantoaxial nonunions
Authors: Dickman Curtis A. , Sonntag Volker K. H.
Published: June 2009

✓ Sixteen patients referred for atlantoaxial fixation failures were treated surgically with revision procedures during the past decade. Of these 16 patients, atlantoaxial instability occurred because of rheumatoid arthritis in five, os odontoideum in seven, transverse ligament disruption in two, and odontoid fracture nonunion in two. The 16 individuals (10 men, six women; mean age 43.7 years; age range 20–77 years) had undergone a total of 20 C1–2 internal fixation procedures that failed.

Surgical strategies for definitive revision of the nonunions in these 16 subjects included 10 rigid internal fixations with transarticular screws, three revised C1–2 fixations with autogenous bone struts and wire or cables, and three extended fixations with occipitocervical instrumentation. Autogenous grafts were used in all revisions. A postoperative halo brace was used in five individuals with osteoporotic bone; all patients wore a restrictive postoperative cervical orthosis.

Postoperatively, 15 patients (94%) had a stable construct (mean follow up 35 months; range 12–79 months), which included 13 osseous unions and two stable fibrous unions. One patient had nonunion; he fractured his anterior C1–2 transarticular screws 2 years postoperatively. He had occipital radicular pain without myelopathy but refused further surgery.

Atlantoaxial pseudarthroses were effectively treated by addressing the pathological, biomechanical, and technical reasons for failed fusion. Successful fusion after reoperation was improved by using autologous bone grafts, adequately controlling atlantoaxial motion (with rigid transarticular screws internally or externally with a halo vest), compressing the bone grafts between the arches of C-1 and C-2 with wire cables, meticulously preparing the fusion bed, and by optimizing the pharmacological and clinical parameters to promote bone healing.
Posterolateral cervical or thoracic approach with spinal cord rotation for vascular malformations or tumors of the ventrolateral spinal cord
Authors: Martin Neil A. , Khanna Rohit K. , Batzdorf Ulrich
Published: June 2009

✓ This report describes a technique for exposing the ventrolateral quadrant of the spinal cord through an extended posterolateral approach that can be used in both cervical and thoracic regions. The surgical technique includes the following: 1) a midline skin incision with a transverse extension at the level of pathology; 2) unilateral division and retraction of the paraspinous muscles; 3) laminectomy and unilateral removal of facets and pedicles; 4) dural incision over the dorsal root entry zone; 5) multilevel division of the ipsilateral dentate ligaments; and 6) elevation and rotation of the spinal cord with dentate traction stitches. This technique provides exposure of the ventral root entry zone, the ipsilateral half of the ventral surface of the cord, and the anterior spinal artery. The surface of the spinal cord beyond the anterior spinal artery is not seen.

This approach has been used for the treatment of seven ventrolateral spinal cord lesions: five spinal arteriovenous malformations (two Type II, one Type III, two Type IV), one hemangioblastoma, and one cavernous angioma. All the lesions were completely excised. Two patients had mild new neurological deficit after surgery, and one adolescent developed mild asymptomatic thoracic kyphosis, but no other spinal instability was observed over a follow-up period of 1 to 4 years. This operative approach provides significant advantages for ventrolateral perimedullary or intramedullary lesions of the cervical or thoracic spinal cord.
Functional magnetic resonance imaging of sensory and motor cortex: comparison with electrophysiological localization
Authors: Puce Aina , Constable R. Todd , Luby Marie L. , McCarthy Gregory , Nobre Anna C. , Spencer Dennis D. , Gore John C. , Allison Truett
Published: June 2009

✓ Functional magnetic resonance (MR) imaging was performed using a 1.5-tesla MR system to localize sensorimotor cortex. Six neurologically normal subjects were studied by means of axial gradient-echo images with a motor task and one or more sensory tasks: 1) electrical stimulation of the median nerve; 2) continuous brushing over the thenar region; and 3) pulsed flow of compressed air over the palm and digits. An increased MR signal was observed in or near the central sulcus, consistent with the location of primary sensory and motor cortex.

Four patients were studied using echo planar imaging sequences and motor and sensory tasks. Three patients had focal refractory seizures secondary to a lesion impinging on sensorimotor cortex. Activation seen on functional MR imaging was coextensive with the location of the sensorimotor area determined by evoked potentials and electrical stimulation. Functional MR imaging provides a useful noninvasive method of localization and functional assessment of sensorimotor cortex.
Detection of tumor necrosis factor-α protein and messenger RNA in human glial brain tumors: comparison of immunohistochemistry with in situ hybridization using molecular probes
Authors: Roessler Karl , Suchanek Gerda , Breitschopf Helene , Kitz Klaus , Matula Christian , Lassmann Hans , Koos Wolfgang Th.
Published: June 2009

✓ Tumor necrosis factor-α (TNFα) protein and messenger (m)RNA distribution was studied in biopsy samples of glial brain tumors, using immunohistochemistry andin situhybridization with molecular probes, to investigate the role of this cytokine in tumor proliferation and immunological host defense. Focal expression of TNFα was detected in four of four glioblastomas, one of two anaplastic astrocytomas, and four of five low-grade astrocytomas, regardless of their subtype or grade of malignancy, but in none of the normal peritumoral brain tissues used as controls. The TNFα protein and mRNA were present in reactive astrocytes and protoplasmic tumor cells, confined to areas of leukocyte or T-lymphocyte infiltration, and less pronounced in tumor cells at the edge of necrosis. Additionally, TNFα reactivity was found in infiltrating macrophages and perivascular microglia. Immunohistochemistry andin situhybridization for TNFα showed comparable reaction patterns and numbers of TNFα-positive cells, even though the sensitivity ofin situhybridization was significantly higher. Quantitative evaluation of TNFα protein, TNFα mRNA, and leukocyte infiltration revealed a significant positive correlation between the TNFα-positive reactive astrocytes and the number of lymphocytes present in corresponding areas. Together, these data lead to the conclusion that TNFα in reactive astrocytes and monocytic cells within tumor areas of high leukocyte infiltration and in tumor cells at the border of necrosis may represent one defense pathway of the immune system against tumor proliferation.
Structural heterogeneity within the axis: the main cause in the etiology of dens fractures
Authors: Amling Michael , Pösl Martin , Wening Volker J. , Ritzel Holger , Hahn Michael , Delling Günter
Published: June 2009

✓ Fractures of the odontoid process are potentially serious injuries; Type II and III fractures, as described by Anderson and D'Alonzo, are seen in the emergency room especially in young adolescents and individuals over 60 years of age. The etiology of these fractures is still controversial. Malunion and nonunion in both types of fractures are presumed to be due to insufficient external or internal fixation, but this theory has not been fully explained.

To examine these issues, the authors expanded their prior studies of the anatomy of the axis. For histomorphometric analysis of cancellous and cortical bone, the axis was removed in 37 autopsies (26 normal and 11 osteoporotic cases) and sectioned in the sagittal plane to a thickness of 1 mm using a surface-stained block-grinding technique. The base of the dens is the region of least resistance for fractures because of its reduced trabecular bone volume, a poorer trabecular interconnection, and a cortical thickness one-third that of the axis. In all cases, trabeculae were disconnected from the trabecular lattice, and in 30%, microcallus formations were demonstrated in the base of the dens. A special filigree type of trabeculae in the base of the dens is often seen in patients with osteoporosis; microarchitectural differences of cancellous bone between the base of the dens and the other regions of the axis are also markedly increased.

The authors infer from the data that the bone structure of the axis is responsible for the location, distribution, and frequency of fractures of the odontoid process in normal healthy bone and this frequency is greatly increased in individuals with osteoporosis. The deficiency of bone mass within the base also suggests a new explanation for the occurrence of nonunions, even after treatment of fractures of the base of the dens.
Ischemic optic neuropathy following lumbar spine surgery
Authors: LEE Andrew G.
Published: June 2009

✓ This 48-year-old hypertensive man, a cigarette smoker, awoke in the recovery room with visual loss in the right eye after uncomplicated lumbar spine surgery. His intraoperative blood pressure had been maintained at relatively low levels to reduce bleeding; a loss of 1500 cc of blood was reported. Postoperative hemoglobin was 4.2 g/dl less than the preoperative hemoglobin; however, the patient did not receive a blood transfusion. A postoperative ophthalmological examination revealed decreased visual acuity, color vision, and visual field in the right eye. The right optic nerve and retina were initially normal but the patient eventually developed optic nerve atrophy consistent with the clinical diagnosis of ischemic optic neuropathy.

Neurosurgeons should be aware that this condition may follow uncomplicated lumbar spine surgery and should obtain prompt ophthalmological consultation when patients develop postoperative visual loss. Aggressive and rapid correction of blood pressure and hematocrit may be helpful in individuals who develop ischemic optic neuropathy after lumbar spine surgery.
Spinal epidural hematoma following coronary thrombolysis with tissue plasminogen activator
Authors: Sawin Paul D. , Traynelis Vincent C. , Follett Kenneth A.
Published: June 2009

✓ Two cases of spinal epidural hematoma following intravenous administration of recombinant tissue-type plasminogen activator are presented. Both patients received thrombolytic therapy for acute myocardial infarction; back pain and progressive neurological dysfunction ensued, secondary to spinal cord compression caused by epidural hematoma. Both individuals underwent emergency surgery for decompression and hematoma evacuation, resulting in improvement in neurological function. The current status of thrombolytic therapy is reviewed, with emphasis on complications of therapy that require neurosurgical intervention.
Delayed hyponatremia after transsphenoidal surgery for pituitary adenoma
Authors: Kelly Daniel F. , Laws Edward R. , Fossett Damirez
Published: June 2009

✓ Hyponatremia, usually attributed to the syndrome of inappropriate secretion of antidiuretic hormone, typically occurs in a delayed fashion following transsphenoidal removal of a pituitary adenoma. In a series of 99 consecutive patients who underwent transsphenoidal surgery for pituitary adenoma, nine patients developed delayed hyponatremia, seven of whom were symptomatic. Of these seven patients, four had been discharged from the hospital and required readmission on postoperative Day 7 to 9. In the nine patients who developed hyponatremia, on the average, serum sodium levels began to fall on Day 4 and reached a nadir on Day 7 (mean serum sodium nadir 123 mmol/L). The development of delayed hyponatremia was associated with the presence of a macroadenoma in eight of the nine patients.

Seven of the nine patients had serum sodium levels less than 130 mmol/L and required treatment. One patient was treated with fluid restriction alone and six were treated with both fluid restriction and intravenous urea therapy. Twenty-four and 48 hours after urea administration, serum sodium levels rose by an average of 6 and 10 mmol/L, respectively, and at discharge, levels averaged 136 mmol/L. Intravenous administration of urea provides a rapid yet safe means of correcting symptomatic hyponatremia when fluid restriction alone is inadequate. In this article, the authors discuss the pathogenesis of delayed hyponatremia.
Reoperative management of intracranial aneurysms
Authors: Giannotta Steven L. , Litofsky N. Scott
Published: June 2009

✓ Nineteen patients underwent 20 operative procedures for the treatment of recurrent or residual aneurysms. There were 13 small, three large, and four giant lesions; with one exception, all were in the anterior circulation. Five individuals presented with recurrent subarachnoid hemorrhage, six were referred for symptoms of mass effect, and nine were known to have had inadequate treatment at the time of the initial operative procedure. The average time interval from initial treatment to either recurrent subarachnoid hemorrhage or compressive effects was 10.5 and 9.75 years, respectively.

No deaths resulted from the reoperative procedures. Two patients suffered moderate disability and one had severe disability. Malpositioned or slipped clips, intraoperative rupture, and inadequate exposure were responsible for 75% of the initial operative failures. The technical difficulty of the reoperative procedure correlated with the length of time between initial and reoperative treatment, the presence of clips and coating agents, and the complexity of the lesion. A classification scheme for preoperative planning and case selection is proposed based on the technical adjuncts required for reoperative aneurysm procedures.
Elective surgery for asymptomatic, unruptured, intracranial aneurysms: a cost-effectiveness analysis
Authors: King Joseph T. , Glick Henry A. , Mason Thomas J. , Flamm Eugene S.
Published: June 2009

✓ Cost-effectiveness analysis uses both economic and clinical outcomes data to evaluate treatment options. In this era of economic constraints on health care, treatments that are not cost-effective will increasingly be denied public and private insurance reimbursement. The authors used mathematical modeling techniques to assess the cost-effectiveness of elective surgery for the treatment of asymptomatic, unruptured, intracranial aneurysms. Input values for the Markov model used in this study were determined from both the literature and clinical judgment. Direct medical costs for hospitalization and physician fees were derived from Medicare cost reports and resource-based relative-value units, expressed in 1992 U.S. dollars. Costs and benefits were discounted at an annual rate of 5%.

Using baseline model assumptions for a 50-year-old patient, elective aneurysm surgery provides an average of 0.88 additional quality-adjusted life years (QALYs) compared with nonsurgical treatment. However, prompt elective surgery ($23,300) costs more than expectant management ($2100), in which only patients whose aneurysms rupture incur treatment costs. Combining the outcomes and cost data, the incremental cost-effectiveness of elective aneurysm surgery is $24,200 per QALY, which is comparable to other accepted medical or surgical interventions, such as total knee arthroplasty ($15,200/QALY) or antihypertensive therapy in a 50-year-old patient ($29,800/QALY).

Prompt elective surgery for asymptomatic, unruptured, intracranial aneurysms is recommended as a cost-effective use of medical resources provided: 1) surgical morbidity and mortality remain at reported levels; 2) the patient has a life expectancy of at least 13 additional years; and 3) the patient experiences a decrease in quality of life from knowingly living with an unruptured aneurysm.
Quantification of operative benefit for unruptured cerebral aneurysms: a theoretical approach
Authors: Chang Han Soo , Kirino Takaaki
Published: June 2009

✓ The indications for surgery on unruptured asymptomatic cerebral aneurysms are still unclear. In this report, the authors use mathematical methods to attempt to quantify the benefit of surgery for unruptured aneurysms.

Theoretical survival curves for either operative or conservative treatment were obtained by solving differential equations on the survival rate of a patient harboring an unruptured aneurysm. Patients' life expectancies were calculated as areas under these curves, and operative benefit was quantified as a gain in average life expectancy. To analyze morbidity, two concepts were introduced: premorbid survival rate and average premorbid survival period, and the operative gain of average premorbid survival period was calculated under certain assumptions.

Larger operative benefit was observed in younger patients, with increasingly less benefit in the elderly. The operative gain of average life expectancy was 3.9 years for a 40-year-old patient, 2.4 years for 50, 1.3 years for 60, and 0.6 years for a 70-year-old. Quantified operative benefit is presented in a table for various patient ages, yearly rupture rates, and expected operative morbidity and mortality.

This mathematical method would be useful to both surgeons and patients in making their decisions on surgery.
Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury
Authors: Greene Karl A. , Marciano Frederick F. , Johnson Blake A. , Jacobowitz Ronald , Spetzler Robert F. , Harrington Timothy R.
Published: June 2009

✓ The presence of traumatic subarachnoid hemorrhage (tSAH) on admission computerized tomography (CT) scans obtained from patients suffering from severe, nonpenetrating head injury has been shown to be associated with a worse outcome than the injury alone would warrant. However, no previous study has provided a simple means of relating the amount of tSAH, its location, or other abnormal findings on initial head CT scans to outcome in patients with nonpenetrating head injury. In this study, admission head CT scans from 252 patients with tSAH, treated at a single institution, were reviewed to ascertain thickness of the tSAH; its location; evidence of mass lesion(s); shift of midline structures (≤ 5 mm vs. > 5 mm); basal cistern effacement; and cortical sulcal effacement. The CT scans were then organized into Grades 1 to 4 with 1 indicating thin tSAH (≤ 5 mm); 2, thick tSAH (> 5 mm); 3, thin tSAH with mass lesion(s); and 4, thick tSAH with mass lesion(s). A stepwise regression analysis of CT features ranked them in descending order of contribution to Glasgow Outcome Scale (GOS) scores at the time of discharge from acute hospitalization as follows: basal cistern effacement, thickness of tSAH, cortical sulcal effacement, presence of mass lesion(s), and location of tSAH. A shift of midline structures was not found to be a significant variable. Further analysis comparing CT grades and admission postresuscitation Glasgow Coma Scale (GCS) scores was highly significant. Patients with lower CT grades had better admission GCS values and discharge GOS scores than those with higher CT grades. From their experience, the authors conclude that their CT grading scale is simple and reliable and relates significantly to outcome at the time of discharge from acute hospitalization.
Controlled lumbar drainage in pediatric head injury
Authors: Levy David I. , Rekate Harold L. , Cherny W. Bruce , Manwaring Kim , Moss S. David , Baldwin Hillel Z.
Published: June 2009

✓ A retrospective study of external lumbar subarachnoid drainage in 16 pediatric patients with severe head injuries is presented. All patients had Glasgow Coma Scale scores of 8 or lower at 6 hours postinjury and were initially treated with ventriculostomy. Five patients required surgical evacuation of focal mass lesions. All patients manifested high intracranial pressures (ICPs) refractory to aggressive therapy, including hyperventilation, furosemide, mannitol, and in some cases, artificially induced barbiturate coma. After lumbar drainage was instituted, 14 patients had an abrupt and lasting decrease in ICP, obviating the need for continued medical management of ICP. In no patient did transtentorial or cerebellar herniation occur as a result of lumbar drainage. It was also noted retrospectively that the patients in this study had discernible basilar cisterns on computerized tomography scans. Fourteen patients survived; eight made good recoveries, three are functional with disability, and three have severe disabilities. Two patients died, most likely from uncontrolled ICP before the lumbar drain was placed. It is concluded that controlled external lumbar subarachnoid drainage is a useful treatment for pediatric patients with severe head injury when aggressive medical therapy and ventricular cerebrospinal fluid evacuation have failed to control high ICP. Selected patients with elevated ICP, which may be a function of posttraumatic cerebrospinal fluid circulation disruption and/or white matter cerebral edema, can be treated with this modality, which accesses the cisternal spaces untapped by ventriculostomy.
Prognosis for mental function in scaphocephaly
Authors: Arnaud Eric , Renier Dominique , Marchac Daniel
Published: June 2009

✓ Three hundred ninety-six children with scaphocephalies were prospectively studied to analyze the correlation between age, intracranial pressure (ICP), and mental function outcome. The ICP measurements and the early and late psychometric assessments were compared. The influence of surgery, when performed, was analyzed. In most cases, the mental function outcome of the patients was good whether or not they had undergone surgery. The mental level and the frequency of increased ICP both correlated with patient age. A correlation was found between the early and late psychometric assessments in all patients. Thus, the main predictive factor of mental function outcome appears to be the initial developmental level.
Altered reactivity of human cerebral arteries after subarachnoid hemorrhage
Authors: Onoue Hisashi , Kaito Nobuyoshi , Akiyama Masahiko , Tomii Masato , Tokudome Shogo , Abe Toshiaki
Published: June 2009

✓ To investigate the effects of subarachnoid hemorrhage (SAH) on the responsiveness of human cerebral arteries to vasoactive substances, the authors measured the isometric tension generated in helical strips of basilar and middle cerebral arteries isolated from human cadavers Contractions caused by KCl, prostaglandin F2α, noradrenaline, and serotonin were reduced in arteries obtained from cadavers with aneurysmal SAH damage and compared to those obtained from cadavers with no indication of intracranial diseases. Endothelium-dependent relaxation elicited by substance P and bradykinin, and endothelium-independent relaxation induced by prostaglandin I2and nitroglycerin were also markedly decreased in arteries affected by SAH. However, the reduction in relaxation response to prostaglandin I2was significantly less than that to the other vasodilator agents. These results indicate that human cerebral artery functions are severely impaired after SAH and that poor responses to vasoactive agents may result primarily from dysfunction of smooth-muscle cells.