Search

✓ A sensitive quantitative index for predicting optimal electrode position in percutaneous anterolateral cordotomy was determined by electrical stimulation through the lesioning electrode. If the threshold for pain elicited by the stimulation electrode was less than 300 µA, a 5-sec radiofrequency lesion of 50 mA would produce complete contralateral analgesia with no weakness. When the pain threshold exceeded 300 µA, incomplete or no analgesia would result with the standard single lesion. The results further suggested that the fibers in the anterolateral quadrant that transmit pain are discretely rather than diffusely localized.

CT-guided stereotactic biopsy of lower brain stem lesions in 7 consecutive cases is discussed. A frontal transincisural approach was used. Five patients had astrocytomas histologically. The single patient who had undergone empirical radiation therapy prior to tissue diagnosis revealed only necrosis. One patient was found to have pathology suggestive of Leigh''s disease. This patient was not radiated and is the first alive adult to have this diagnosis confirmed. Although controversy still exists in the management of brain stem lesions, we intend to demonstrate the value of tissue diagnosis in the management of such lesions.

✓ Six cases of pancreatitis following spinal cord injury are presented. No single, etiologically accepted mechanism already postulated to cause pancreatitis can account for all the cases reported. The authors hypothesize that spinal cord disruption may produce pancreatitis by sympathetic-parasympathetic nervous system imbalance resulting in over-stimulation of the sphincter of Oddi. This may lead to stasis of secretions with absorption of amylase into the systemic circulation, and structural pancreatic damage. Pancreatitis in those with cord injuries is easily overlooked because abdominal pain is usually absent and fever is usually attributed to more frequently occurring pulmonary or urinary tract infections. Recognition of this complication is important in order to decrease the morbidity and mortality that follows spinal cord damage.

In 1972 the authors developed a system for monitoring intracranial pressure (ICP) from the subarachnoid space over the cerebral hemispheres (1). The system is based on a specially designed hollow screw. The screw is threaded into the skull through a 5 mm twist drill hole after opening the dura and arachnoid with a small currette. The screw is connected to a strain gauge transducer by means of saline filled tubing to record ICP. The system is calibrated by opening the bedside transducer to air through a bacteriologic filter. The screw insertion is performed in the neurosurgical ward under local anesthesia.

The objective of this study in patients with severe mechanical brain injury is to test the following hypotheses: (A) that controlling cerebral perfusion pressure (CPP) in a range of 75 + 20 mmHg would limit progressive brain swelling when used in conjunction with controlled ventilation, and (B) that mortality in such patients who arrive alive at the hospital usually results from progressively elevating ICP, given that systemic medical management is adequate, continuous and intensive. We have also examined the admission intracranial pressure in patients with severe mechanical brain injury, and correlated this intracranial pressure with the neurological examination and ultimate result.

Previous research (Adametz, 1959) has shown that two-step bilateral lesions of the reticular formation in cats produce minimal behavioral disruption compared to one-step bilateral lesions, which produce profound behavioral suppression. We systematically examined alterations in forebrain acetylcholine (ACh) content and neurologic tolerance to one-step and two-step bilateral and unilateral lesions of the pontomesencephalic reticular formation (PMRF) in rats. One-step and two-step bilateral lesions separated by 1 or 5 days produced irreversible bilateral motor dysfunction. Survival after lesioning was 10%, 20%, and 0%, respectively. Unilateral lesion or two-step bilateral lesions separated by 15 or 30 days produced transient (less than 3 days) contralateral motor dysfunction. Survival after lesioning was 90%, 90%, and 100%, respectively. Within 24 h after one-step bilateral lesions, ACh content was significantly decreased bilaterally in thalamus, frontal cortex, amygdala, hippocampus, and basal forebrain. Within 5 days after unilateral lesioning, ACh content was significantly decreased ipsilaterally in the thalamus, amygdala, and hippocampus and had returned to control values by day 10 in the thalamus and hippocampus. The increased neurologic tolerance and recovery of ACh content in two-step bilateral PMRF lesions demonstrate important functional and neurochemical plasticity to brain injury. Although not directly addressing mechanisms of neural plasticity, this research examined possible associations between neurologic tolerance to PMRF lesions and neurochemical markers of forebrain ACh activity.

✓ The authors report a follow-up study of 103 American soldiers who were treated for brain wounds at one neurosurgical facility in Vietnam. The estimated mortality after evacuation from the war zone was 6% to 8%. Severe brain wounds, meningitis, and pulmonary emboli accounted for the majority of the late deaths. Thirty-four per cent had post-debridement complications such as retained bone fragments (16%), infection (15%), cerebrospinal fluid leaks or wound dehiscence (2%). Removal of retained intracerebral bone was associated with occasional complications but unquestionably prevented several late brain abscesses; only two patients in this series developed a late brain abscess. About half of those who were evacuated from Vietnam with retained intracerebral bone harbored fragments that were contaminated with bacteria.

Severe head injury remains a major problem despite advances in recent years. The mortality of patients with a coma score of eight or less is still between 45–55% (Miller et al. 1981). In an attempt to improve outcome in a significant number of these patients, we have directed our efforts toward therapeutically influencing the brain and its environment after a severe head injury. Severe mechanical brain injury initiates a series of complex events in the brain which are thought to secondarily influence the ultimate outcome of the patient. One of these proposed secondary events is cerebral acidosis. The presence of cerebral acidosis has been inferred by the presence of lactate in ·the CSF of patients sustaining a severe mechanical brain injury (Cold et al. 1975, Enevoldsen et al. 1977, Sood et al. 1980). In addition, prognostic significance has been attached to high levels of lactate in the CSF after a severe brain injury (Crockard et al. 1972; Seitz and Ocker 1977). Furthermore, it has been shown that acidosis itself, when present as the result of any pathologic process, is harmful to the brain (Pulsinelli and Petito 1983). It was felt therefore that outcome from severe head injury might be improved if cerebral acidosis present after a head injury was treated.

✓ In 22 patients to be operated on for brain tumors or cerebral aneurysms, the effect of osmotic diuresis was compared with that of osmotic-loop diuresis on plasma and cerebrospinal fluid (CSF) electrolytes, and water and ion excretion. Mannitol or mannitol plus furosemide were used to reduce brain bulk. After treatment with thiopental and hyperventilation, patients received randomly a rapid infusion of mannitol (1.4 gm/kg), or mannitol (1.4 gm/kg) plus furosemide (0.3 mg/kg). Brain shrinkage was considerably greater and more consistent with mannitol plus furosemide than with mannitol alone. However, hyponatremia, hypokalemia, hypochloremia, and hyperosmolality were also more marked (p < 0.05) with mannitol plus furosemide than with mannitol. The rate of water and ion excretion was even more striking. At 30 minutes after absorption of mannitol alone, water excretion peaked at 17 ml/min, and gradually decreased to 3.8 ml/min 70 minutes later. With mannitol plus furosemide, during an identical time course, initial water excretion was 30 ml/min, followed by a further rise to 42 ml/min and then a decline to 17 ml/min. At peak diuresis after mannitol, Na+ and Cl− excretion averaged 0.57 and 0.62 mEq/min, respectively. This compares with mean values of 3.7 and 4.12 mEq/min for Na+ and Cl−, respectively, after mannitol plus furosemide. Although optimum brain shrinkage is achieved with osmotic-loop diuresis, the rapid electrolyte depletion (Na+ and Cl−) must be corrected to avoid altered sensorium during the patients' postoperative course.

In phase-I clinical trials of adoptive immunotherapy using lymphokine-activated killer (LAK) cells plus recombinant interleukin-2 (rIL-2) (Cetus) for the treatment of malignant glioma, we observed that blood mononuclear cells (MNC) from patients dependent on dexamethasone for management of cerebral edema produced substantially less LAK activity as compared to MNC of normal blood donors or glioma patients not receiving steroid therapy. Therefore, we examined the in vitro effects, brought about by therapeutically attainable concentrations of various corticosteroids, on the proliferative response, production of γ interferon (IFN-γ), and induction of LAK activity from blood MNC of normal donors. Incubation in media containing rIL-2 (1000 U/ml) with either dexamethasone, hydrocortisone, methylprednisolone, or prednisolone profoundly affected all of these parameters. First, while 0.01 μg/ml of either dexamethasone or hydrocortisone caused a slight enhancement of the mitogenic response of lymphocytes to phytohemagglutinin, a dose-dependent decline occurred as concentrations increased to 10 μg/ml. The addition of prednisolone and methylprednisolone elicited a dose-dependent inhibition of lymphocyte proliferation over the entire concentration range tested. At 0.1 μg/ml or higher, dexamethasone, hydrocortisone, methylprednisolone and prednisolone significantly (P

The objectives of the present study were to evaluate the relationship between the fractional amplitudes of the EEG derived from power spectral analysis (PSA) of the electroencephalogram (EEG) and depth of coma measured clinically with the Glasgow Coma Score, and to assess the accuracy of PSA in predicting long-term outcome. Thirty-two patients rendered unconscious by blunt head injury (mean (GCS = 7) had intermittent EEG recordings daily from 1-10 days post injury. There was a significant correlation between fractional amplitude of the EEG and the GCS. The rate and magnitude of change in the EEG and GCS were also correlated. There were significant differences in PSA parameters between improved and deteriorated patient groups at the termination of monitoring (p = .02) and in the change of PSA parameters over time (p = .02). Using linear discriminant analysis of PSA parameters, the accuracy of outcome prognostication based on the six month outcome was approximately 75%. Accurate classification of outcome was possible in a number of patients in whom there was little or no change in the GCS during the period of monitoring.

✓ There has been a rapid expansion of knowledge in the field of nutrition and metabolism with regard to the general surgical patient. However, only recently has there been greater appreciation of the benefits of adequate nutrition and appropriate metabolic care of the neurosurgical patient. In this review, the authors attempt to outline 1) the metabolic response to stress in general, and how it applies to the neurosurgical patient; 2) how best to provide adequate nutritional support for the neurosurgical patient; 3) the effects of nutrition on neurotransmitters; and 4) the effect of diet and nutrition on patients with malignant brain tumors.

A study was made in 10 patients with brain tumors of the effect of methylprednisolone sodium succinate (Solu-Medrol) on clinical neurological status, intracranial pressure, and periventricular elastance. Significant clinical improvement and reduction in periventricular elastance both occurred within 24 hours of starting treatment, whereas intracranial pressure was not significantly reduced until the 2nd day of therapy.

Human glioblastoma cell lines showed profound suppression of both suppression of both DNA and RNA synthesis when exposed to supernatants (SNs) of mitogen-activated blood mononuclear cells. Cloning efficiency of these glioma cells also decreased 10- to 500-fold. In monolayer cultures, growth inhibition was evident within 12 h of adding Sn and peaked at 24 h. A decrease in absolute cell number was evident by 72 h. The inhibitory effect of SNs, however, was not permanent as more cells entered S-phase when SN-treated cultures were refed with fresh medium (without SN). The factor(s) responsible for this inhibitory activity was a product of lymphocytes and was produced in comparable amounts by cells of normal blood donors and patients with glioma. The compromised immunological status of glioblastoma patients did not influence their capacity to produce cytostatic lymphokines.

It appears that the level of the cerebral perfusion pressure (CPP) is more critical in patients than the absolute degree of intracranial pressure. Continuous knowledge of the CPP in patients with intracranial mass lesions should permit one to prevent impending or actual ischemic insults from an unexpected or unrecognized depression of the CPP.

The intracranial compliance as measured by the PVI has been considered an important parameter in dynamical analysis of the ICP. The importance of compliance measures in the clinical setting has been emphasized by several investigators; however, the number f clinical investigations focused on biomechanical indices associates with head injury have been relatively few. The aim of this investigation was to study the temporal relationship between intracranial compliance and ICP in a group of severely head injured patients. Our objectives were to characterize the biomedical profile of the head injured patient immediately upon stabilization in the ICU setting and to follow the temporal course of ICP and PVI during the five days post injury.

Growth of cultured human glioblastoma cells was profoundly inhibited by concentrated lymphokines prepared from mitogen-activated blood mononuclear cells of normal donors. Cloning efficiency of glioma cells and their absolute number were decreased as well. Partially purified leukoregulin, free of lymphotoxin, tumor necrosis factor and γ-interferon, similarly suppressed DNA synthesis and clonogenicity. The decrease in absolute numbers of tumor target cells indicated that leukoregulin was directly cytolytic as well as cytostatic for human glioblastoma cells. Our data indicate that leukoregulin is at least one of the factors produced by activated lymphocytes which inhibits the proliferation of human glioblastoma in vitro.

✓ A review of postoperative radiographs in hydrocephalic patients treated with ventriculojugular shunts reveals a marked decrease in the CSF fluid spaces, both subarachnoid and intraventricular, reflected in compensatory skull changes and alterations in ventricular configuration. Most of the changes appear to be reversible when shunt malfunction develops, with the exception of acquired synostosis. Exceptions to the generalized changes that can be expected in all cases include absence of changes in the sella turcica in the presence of an intact diaphragma sellae, persistence of the “right angle” sella turcica and concave basi-occiput in patients with an Arnold-Chiari Type II malformation, and shifts of the lateral ventricle when the septum pellucidum is intact. Experimental evidence in shunted hydrocephalic dogs suggests that differential damping of ventricular pulse pressure by the shunt is a factor.

✓ Bacteriological studies were performed on 45 craniocerebral missile wounds incurred in Vietnam within 2 to 4 hours of occurrence. All missiles had penetrated into the brain. Aerobic and anaerobic cultures were taken of the skin wound, brain, and indriven bone fragments. Forty-four of the skin wounds were contaminated, predominantly with staphylococcus. Only five brain wounds showed bacterial contamination 2 to 4 hours after wounding, indicating that many missile tracks within the brain are initially sterile. Of the patients who had early debridement, 45% had contaminated bone within the brain; possibly up to 75% of all indriven bone chips were sterile. The authors draw the following conclusions. Complete brain debridement with removal of all indriven bone is ideal. Accessible retained bone should be removed by reoperation. Multiple reoperations for an inaccessible retained fragment are inadvisable, however, as fatalities or severe neurologic residua may result. An individual indriven bone chip has a small likelihood of bacterial contamination provided initial debridement was done early. This knowledge may justify an expectant policy in certain individuals harboring an inaccessible retained bone fragment. The retained fragment would be removed only if untoward difficulties develop.

✓ A case is reported in which a ruptured intracerebral aneurysm had been infected by Neisseria meningitidis. Evacuation of the resulting hematoma, clipping the aneurysm and antibiotic therapy resulted in a satisfactory recovery.

Rats were trained in Tolman’s “sunburst” apparatus modified to eliminate visual cues. Results consistent with his hypothesis of “cognitive maps” were obtained. There was a tendency to take the right sided test pathways pointing in the general direction of the food box. When the number of left and right turns in the training procedure were made equal and the ultimate turn was to the left, no tendency to turn right was found during testing.

In a matter of hours the neurologic status of two hypertensive patients deteriorated to coma. Cranial computed tomography (CT) showed mild to moderate cerebellar hemorrhage and secondary hydrocephalus. Ventriculostomy resulted in clinical improvement within 20 minutes and obviated the need for suboccipital craniectomy. Both patients made a very satisfactory recovery. Similar patients have occasionally been observed by others. Ventriculostomy should be considered for patients with cerebellar hemorrhage who have hydrocephalus by CT scan and undergo progressive neurologic deterioration. Because the frequency of improvement and the risk of upward cerebellar herniation following ventriculostomy is unknown, immediate surgical evacuation of the hemorrhage should be anticipated.