Journal of neurosurgery
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Journal of neurosurgery · Feb 2007
Case ReportsTailor-made orbitocranioplasty for a sphenorbital encephalocele presenting as pulsatile exophthalmos. Case report.
Basal encephaloceles account for only 1.5% of all encephaloceles. Within this group, the sphenorbital type is quite rare but causes herniation of the brain into the orbit, leading to pulsatile exophthalmos and disturbance of visual acuity. The authors present a case of successful orbitocranioplasty for a sphenorbital encephalocele in which they used a skull model in preparation for the operation. ⋯ A skull model using 3D CT data is useful for determining the most appropriate strategy for reconstruction. Hydroxyapatite ceramic implants have high affinity to autologous bone and thus are suitable for children. In cases such as the present one, however, the patient should be observed carefully to ensure that there is not an imbalance between the implant and the still growing autologous skull.
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Journal of neurosurgery · Feb 2007
Image-guided convection-enhanced delivery of gemcitabine to the brainstem.
To determine if the potent antiglioma chemotherapeutic agent gemcitabine could be delivered to the brainstem safely at therapeutic doses while monitoring its distribution using a surrogate magnetic resonance (MR) imaging tracer, the authors used convection-enhanced delivery to perfuse the primate brainstem with gemcitabine and Gd-diethylenetriamine pentaacetic acid (DTPA). ⋯ Six primates underwent convective brainstem perfusion with gemcitabine (0.4 mg/ml; two animals), Gd-DTPA (5 mM; two animals), or a coinfusion of gemcitabine (0.4 mg/ml) and Gd-DTPA (5 mM; two animals), and were killed 28 days afterward. These primates were observed over time clinically (six animals), and with MR imaging (five animals), quantitative autoradiography (one animal), and histological analysis (all animals). In an additional primate, 3H-gemcitabine and Gd-DTPA were coinfused and the animal was killed immediately afterward. In the primates there was no histological evidence of infusate-related tissue toxicity. Magnetic resonance images obtained during infusate delivery demonstrated that the anatomical region infused with Gd-DTPA was clearly distinguishable from surrounding noninfused tissue. Quantitative autoradiography confirmed that Gd-DTPA tracked the distribution of 3H-gemcitabine and closely approximated its volume of distribution (mean volume of distribution difference 13.5%). Conclusions. Gemcitabine can be delivered safely and effectively to the primate brainstem at therapeutic concentrations and at volumes that are higher than those considered clinically relevant. Moreover, MR imaging can be used to track the distribution of gemcitabine by adding Gd-DTPA to the infusate. This delivery paradigm should allow for direct therapeutic application of gemcitabine to brainstem gliomas while monitoring its distribution to ensure effective tumor coverage and to maximize safety.
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Journal of neurosurgery · Feb 2007
Addition of intravenous N-methyl-D-aspartate receptor antagonists to local fibrinolytic therapy for the optimal treatment of experimental intracerebral hemorrhages.
Fibrinolytic therapy with recombinant tissue plasminogen activator (rtPA) is considered a treatment option in patients with deep-seated intracerebral hemorrhage (ICH). Nevertheless, the results of animal experiments have shown that tPA exerts pleiotropic actions in the brain, including regulation of vasoactivity, amplification of calcium conductance by cleavage of the N-methyl-D-aspartate (NMDA) receptor subunit, and activation of metalloproteinases, which increase excitotoxicity, damage the blood-brain barrier, and worsen edema. The authors investigated whether the noncompetitive NMDA receptor antagonist MK801 can be used as an adjuvant therapy in combination with rtPA to attenuate the unfavorable delayed edema formation and inflammation observed following rtPA therapy in an experimental porcine model of ICH. ⋯ As suggested by the reduction in delayed edema volume and the inflammatory response, MK801 modifies the neurotoxic properties of rtPA but not those of blood degradation products. Possibly, fibrinolytic therapy of ICH is more beneficial if combined with agents such as MK801.
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Journal of neurosurgery · Jan 2007
Recognition and management of delayed hyponatremia following transsphenoidal pituitary surgery.
The goal of this study was to assess the incidence of symptomatic and occult hyponatremia in patients who had undergone transsphenoidal pituitary surgery. ⋯ Delayed hyponatremia occurs more frequently than was previously suspected in patients who have undergone transsphenoidal surgery, especially in female patients and those who have previously had transient DI. The majority of hyponatremic patients remain asymptomatic. Obtaining a serum sodium value on an outpatient basis 1 week after pituitary surgery is helpful in recognition, risk stratification, and subsequent intervention, and may prevent potentially serious complications.
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Journal of neurosurgery · Jan 2007
Case ReportsTransfemoral vein placement of a ventriculoatrial shunt. Technical note.
Acceptable cavities for the distal portion of a cerebrospinal fluid diversion shunt include the peritoneal, pleural, and atrial cavities. The authors report on a patient in whom placement into the peritoneal cavity failed, the pleural cavity was not an option, and access to the right atrium was not technically possible via standard cannulation techniques into the veins of the neck and shoulder regions. ⋯ Eight months postoperatively, the patient's condition was at baseline and there were no signs of shunt malfunction. This technique may prove useful when other measures have failed.