Neurosurgery
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Comparative Study
Effects of droperidol, pentobarbital, and ketamine on myogenic transcranial magnetic motor-evoked responses in humans.
Myogenic motor-evoked responses to transcranial magnetic stimulation of the motor cortex (tcmag-MERs) may become clinically useful for the noninvasive assessment of motor pathway conduction during surgery. However, application is hindered because most anesthetic regimens result in severe depression of tcmag-MER amplitudes. As part of our systematic attempts to identify anesthetic agents and supplements suitable for use during tcmag-MER recording, we studied the effect of bolus doses of pentobarbital (1.5 mg/kg), droperidol (0.07 mg/kg), or ketamine (1 mg/kg), administered intravenously, on compound muscle action potentials to transcranial magnetic stimulation in five healthy volunteers. ⋯ Onset latency was unchanged after any drug. These data indicate that tcmag-MERs are moderately depressed after droperidol and pentobarbital but well preserved after ketamine. Ketamine may be a more suitable supplement to opioid/nitrous oxide anesthesia than droperidol or pentobarbital.
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Hydrosyringomyelia was produced experimentally by the injection of kaolin into the cisterna magna of the rabbit, and the ultrastructural changes of the spinal cord surrounding the syrinx were investigated 2, 4, and 6 weeks after injection by transmission electron microscopy. The ependyma at the ventral part of the central canal was flat and stretched, whereas, in the dorsal part, it was split, and the syrinx extended through the dorsal median plane in most animals. Extracellular edema was found in the subependymal white matter and in and around the posterior median septum. ⋯ Sometimes, this further remyelination was abortive, especially where the edema was severe. The ultrastructural changes of the neural tissue and their sequences were identical, in most respects, to those of hydrocephalus and noncommunicating syringomyelia. The oligodendrocytic remyelination with ongoing demyelination found in this model has many similarities to those in experimental hydrocephalus.
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After 3 years of deliberations, The Society of Neurological Surgeons approved a national Neurological Surgery Matching Program in 1983 for residency positions beginning July 1, 1985. All directors of United States neurological surgery residency training programs agreed to participate and abide by the rules of the match. A review of 10 years' experience with 11 matches from 1983 to 1994 indicates full acceptance by both applicants and program directors and a highly successful process and outcome, satisfactory for everyone except for qualified applicants who failed to obtain a residency position. ⋯ Various interesting details about multiple-year applications, International Medical Graduates, and nonstart, transfer, and dropout rates are presented, including the eventual practice activities of residents not completing neurosurgical training. A comparison of all United States medical schools, considering data on applications and matches for neurosurgical residency versus number of senior medical students, reveals wide differences. These differences are probably related to the availability of neurosurgical clerkships, faculty participation in the undergraduate curriculum, and the presence of a neurosurgical residency program.
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Case Reports
Posttraumatic syringomyelia: its characteristic magnetic resonance imaging findings and surgical management.
Posttraumatic syringomyelia should be considered in any patient showing a delayed neurological deterioration after spinal cord injury. The purpose of this article is to assess the posttraumatic syringomyelia on magnetic resonance images and to evaluate the results of its surgical treatment. Fourteen patients with posttraumatic syringomyelia were studied. ⋯ Shunt malfunction was encountered in three of the four syringoperitoneal shunts and in the one ventriculoperitoneal shunt. Final neurological outcomes were satisfactory in all 11 patients who underwent surgery. Motor function improved in eight of nine patients, sensory disturbance improved in five of five patients, and relief of local pain or numbness was obtained in four of four patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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The cases of gigantism sisters with somatotroph adenomas unrelated to multiple endocrine neoplasia (MEN) Type 1 are reported. The sisters grew rapidly since they were 5 or 6 years old and were diagnosed to have gigantism with pituitary adenoma by computed tomographic scan and magnetic resonance imaging. A serum endocrinological examination showed the elevated growth hormone values. ⋯ This incidence is much higher than that of MEN Type 1 patients with pituitary adenomas. The cause of the familial occurrence of pituitary adenomas is still unclear, although autosomal recessive inheritance has been suggested. It has been stated that point mutations in codon 201 or 227 of the Gs alpha gene located in chromosome 20 were found in about 35 to 40% of somatotroph adenomas.(ABSTRACT TRUNCATED AT 250 WORDS)