Neurosurgery
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Terminal myelocystoceles constitute approximately 5% of skin-covered lumbosacral masses and are especially common in patients with cloacal exstrophy. Pathologically, terminal myelocystocele consists of (a) a skin-covered lumbosacral spina bifida (b) an arachnoid-lined meningocele that is directly continuous with the spinal subarachnoid space; and (c) a low-lying, hydromyelic spinal cord that traverses the meningocele and then expands into a large terminal cyst. ⋯ The terminal cyst is lined by ependyma and dysplastic glia, is directly continuous with the dilated central canal of the cord, and probably represents a ballooned terminal ventricle. Patients with terminal myelocystocele have normal intellectual potential and are usually born without neurological deficit, so these defects must be identified and repaired early, before the onset or progression of lower extremity pareses.
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The benefits of continuous epidural morphine infusion using an implanted pump delivery system to control intractable cancer pain have recently been described. Most articles on this subject relate to dosage, technique, degree of pain relief, and tolerance. There are some anticipated complications of the treatment related to the surgical implantation of the system and drug toxicity. ⋯ A fibrous reaction that developed around the catheter tip progressed into a mass. This caused a significant displacement of the spinal cord with the development of long tract symptoms. Identification of this abnormality using myelography and computed tomography led to prompt surgical decompression resulting in improvement of the patient's condition.
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We present a case of tension pneumocephalus after burr hole evacuation of bilateral chronic subdural hematomas. Subsequent treatment was effected with combined twist drill closed system drainage and continuous intrathecal infusion of a physiological solution. The clinical entity, tension pneumocephalus, and the use of continuous subarachnoid infusion and drainage as a method of cerebral reexpansion are discussed.
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The use of the intraventricular or subarachnoid administration of morphine in the treatment of intractable pain secondary to cancer is described. The drug, in doses ranging from 0.33 to 4.00 mg, was administered by the percutaneous injection of an Ommaya reservoir or by a spinal tap. The duration of analgesia ranged from 36 to 150 hours. The indications for and side effects of this type of therapy are considered.
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The intrathecal (i.t.) administration of morphine inhibits nociceptive motor responses and activity in ascending axons evoked by stimulation of nociceptive afferent nerve fibers (nociceptive sensory response) in the rat. The i.t. administration of cholecystokinin octapeptide and ceruletide inhibits nociceptive motor responses, but does not affect ascending nociceptive activity. This shows that drug-induced depression of nociceptive motor responses is not always associated with depression of the nociceptive sensory response of the spinal cord. ⋯ Diazepam, 20 micrograms i.t., reduced activity evoked by afferent A delta and C fiber stimulation and by stimulation of afferent A beta fibers. The depressant effect caused by diazepam, 2 mg/kg i.v., on C fiber-evoked ascending activity was reduced by the i.t. injection of the benzodiazepine antagonist, Ro 15-1788 (40 micrograms), an imidazodiazepine. It is concluded that the depression by diazepam of C fiber-evoked ascending activity contributes to pain relief caused by the drug.