Neurosurgery
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We reviewed 127 patients who were operated upon for adult presentation Chiari malformation and made six conclusions: (a) The clinical examination remains crucial in the diagnosis. (b) The surgical anatomy is highly varied. (c) Syrinxes can be missed on preoperative contrast studies. (d) By a conservative grading system, we determined that 46% of the patients improved during long term follow-up. One-quarter deteriorated over the long run in spite of any treatment. (e) The overall results did not differ whether the treatment was plugging of the central canal plus decompression or decompression alone. (f) In patients with progression, plugging of the central canal obtained superior results. A review of the literature shows that the natural history of this complex disease process has not been established. This history is needed to identify the course of what may be several important factors that lead to the pathological condition in this disease.
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Comparative Study
Furosemide and mannitol in the treatment of acute experimental intracranial hypertension.
Intracranial hypertension was induced in dogs and a small number of baboons by the inflation of epidural balloons. The resulting increased intracranial pressure (ICP) was treated with standard clinical doses of furosemide (0.7 mg/kg), "mini" doses of mannitol (0.75 g/kg), or both agents in combination. ⋯ When results were averaged, furosemide used alone caused a slow reduction in ICP, but the results were variable in individual animals--with ICP actually increased in some. When furosemide and mannitol were given together, the ICP fell rapidly and remained low for considerably longer than after either agent alone.
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A retrospective analysis of the case histories of 21 pediatric patients (ages, 2.5 to 18 years) with a histologically proven diagnosis of brain stem glioma was performed to determine whether patterns of radiographic appearance could be correlated with pathology. Based on the computed tomographic or pneumoencephalographic appearance of the tumor at the time of clinical diagnosis, tumors were divided into four types: central intrinsic (Type I), central exophytic expansion into the 4th ventricle (Type II), eccentric exophytic expansion not involving the 4th ventricle (Type III), and both eccentric and central exophytic expansion (Type IV). ⋯ The presence of a cystic component did not affect survival. High resolution computed tomographic scans, with reconstructed images of the posterior fossa, can predict the presence and location of brain stem tumors and associated cysts and probably the histological nature of the tumor.
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Four cases of tension pneumocephalus after either posterior fossa craniotomy or translabyrinthine resection of acoustic neuroma with or without nitrous oxide anesthesia are described. Three of the operations were performed with the patient in the sitting position, and one was done with the patient in the lateral position. Of the three cases operated in the sitting position, no nitrous oxide was used at any time during anesthesia in one. ⋯ Re-exploration of the surgical wound or twist drill aspiration of the subdural air resulted in prompt recovery of neurological status in three patients, whereas the other patient's neurological status improved gradually without any specific treatment. The role played by nitrous oxide, the mechanisms by which air enters the intracranial space, the contributory factors, and the predisposing surgical conditions of tension pneumocephalus are reviewed and discussed. Dependent drainage of the cerebrospinal fluid, especially in a patient with coexisting hydrocephalus, seems to be the most important factor for the development of this complication.
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Case Reports
Real-time ultrasonography: a useful tool in the evaluation of the craniectomized, brain-injured patient.
Real-time ultrasonography is being used increasingly to establish the diagnosis of and serially assess intraventricular hemorrhage and hydrocephalus in neonates. The procedure requires an open fontanel because scatter from the bone occurs from direct application of the transducer to the skull and bone density precludes satisfactory imaging. With an adult, under circumstances where a bone flap is left out after intracranial procedures and the patient's clinical status is such that the patient cannot be transferred for computed tomographic scanning, real-time ultrasonography allows a safe, noninvasive, bedside demonstration of ventricular size, degree of shift of midline structures, and intraparenchymal and intraventricular lesions.