Journal of neurosurgery
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Journal of neurosurgery · Oct 1999
Cerebral metabolism in experimental hydrocephalus: an in vivo 1H and 31P magnetic resonance spectroscopy study.
Brain damage in patients with hydrocephalus is caused by mechanical forces and cerebral ischemia. The severity and localization of impaired cerebral blood flow and metabolism are still largely unknown. Magnetic resonance (MR) spectroscopy offers the opportunity to investigate cerebral energy metabolism and neuronal damage noninvasively and longitudinally. Previous 1H MR spectroscopy studies have shown an increased lactate resonance that is suggestive of anaerobic glycolysis. The aim of this study was to assess cerebral damage and energy metabolism in kaolin-induced hydrocephalus in adult rats by using in vivo 1H and 31P MR spectroscopy. The presence of lactate was correlated with high-energy phosphate metabolism and intracellular pH. The measurement of relative concentrations of N-acetyl aspartate (NAA), choline (Cho), and total creatine (tCr) served to assess neuronal damage. ⋯ In hydrocephalic rats, ventricular expansion stabilized after 8 weeks. White matter edema was most pronounced during acute hydrocephalus. Lactate peaks were increased at all time points, without a decrease in phosphocreatine (PCr)/Pi and PCr/adenosine triphosphate (ATP) peak ratios, or pH. Possibly lactate production is restricted to periventricular brain tissue, followed by its accumulation in cerebrospinal fluid, which is supported by the long lactate T2 relaxation time. Alternatively, lactate production may precede impairment of ATP homeostasis. The NAA/Cho and tCr/Cho ratios significantly decreased during the acute and chronic stages of hydrocephalus. These changes were not caused by alterations in metabolite T2 relaxation time. The decreases in the NAA/Cho and tCr/Cho ratios implicate neuronal loss/dysfunction or changes in membrane phospholipid metabolism, as in myelin damage or gliosis. It is suggested that 1H MR spectroscopy can be of additional value in the assessment of energy metabolism and cerebral damage in clinical hydrocephalus.
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In this review the authors address the surgical strategies required to resect residual herniated thoracic discs. ⋯ Calcified, large, broad-based, centrally located, or transdural thoracic disc herniations can be difficult to resect. These lesions require a ventral operative approach to visualize the dura adequately for a safe and complete resection.
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Journal of neurosurgery · Oct 1999
Exacerbation of cortical and hippocampal CA1 damage due to posttraumatic hypoxia following moderate fluid-percussion brain injury in rats.
Patients with head injuries often experience respiratory distress that results in a secondary hypoxic insult. The present experiment was designed to assess the histopathological consequences of a secondary hypoxic insult by using an established rodent model of traumatic brain injury (TBI). ⋯ The results of this study demonstrate that a secondary hypoxic insult following parasagittal FPI exacerbates contusion and neuronal pathological conditions. These findings emphasize the need to control for secondary hypoxic insults after experimental and human head injury.
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Journal of neurosurgery · Oct 1999
Intraoperative electromyographic assessment of recurrent laryngeal nerve stress and pharyngeal injury during anterior cervical spine surgery with Caspar instrumentation.
Recurrent laryngeal nerve (RLN) injury occurs after anterior cervical spine procedures. In this study the authors used intraoperative electromyographic (EMG) monitoring of the posterior pharynx as a surrogate for RLN function and monitored endotracheal tube (ET) cuff pressure to determine if there was an association between these variables and clinical outcome. ⋯ Hoarseness immediately after surgery was reported in 38% of patients whereas 15% exhibited severe symptoms. In symptomatic patients the period of intubation had been longer, and the ET cuff pressures had been elevated. In most patients EMG activity increased during insertion of the retractor and decreased after its removal. In these patients a greater number of episodes of elevated EMG activity during surgery were also noted. Two patients experienced prolonged hoarseness, and one required teflon injections of the vocal fold. This patient's EMG activity increased (15-18 times baseline) during surgery. In the few patients who were symptomatic with increased EMG activity, neither the timing nor direction of change could be associated with symptoms. Intubation time and elevated ET cuff pressure were the most important contributors to dysphonia and sore throat after anterior cervical spine surgery.
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Journal of neurosurgery · Oct 1999
Randomized Controlled Trial Clinical TrialSide effects and mortality associated with use of phenytoin for early posttraumatic seizure prophylaxis.
The goals of this study were to determine if the use of phenytoin to prevent early posttraumatic seizures following head injury was associated with significant adverse side effects and also to determine if the reduction in early posttraumatic seizures after phenytoin administration was associated with a change in mortality rates in head-injured patients. ⋯ The results of this study indicate that the incidence of early posttraumatic seizure can be effectively reduced by prophylactic administration of phenytoin for 1 or 2 weeks without a significant increase in drug-related side effects. Reduction in posttraumatic seizure during the 1st week, however, was not associated with a reduction in the mortality rate.