Jewell L. Osterholm

Reanalysis of central cervical cord injury management.

Early investigators indicated that conservative management was superior to operative intervention in the treatment of central cord injuries. Their clinical data suggested that operative treatment, in fact, worsened the condition. Recent experience with this clinical entity, however, indicates that in selected patients operative intervention may be of value in improving the rate and degree of motor recovery. A retrospective study of all individuals admitted to our hospital (Delaware Valley Spinal Cord Injury Center) with central cervical spinal cord injury was done (28 patients). One-half had been treated with medical therapy alone (Group I); the others were treated both medically and surgically (Group II). Medical therapy consisted of intravenous mannitol, dexamethasone, and sodium bicarbonate given during the acute phase of the injury. Both groups were immobilized using either a halo or a Philadelphia collar. Criteria for entry into the surgical group were one or both of the following: (a) failure to improve progressively after an initial period of improvement, with persistent compression of neural tissue visualized on myelography and (b) unacceptable instability of the spinal bony elements. The patients were given neurological scores based on the motor power of the major muscle groups. The stability of the spine was scored using the Panjabi-White scale. The two groups were compared using Students t-test and the two-factor analysis of variance. There was no significant difference in initial neurological scores between the groups. The surgical groups had a higher incidence of instability of the bony elements of the cervical spine, as judged by the Panjabi-White scale.(ABSTRACT TRUNCATED AT 250 WORDS)

A reproducible experimental model of focal cerebral ischemia in the cat

In the past experimental methods used for producing focal cerebral ischemia have had considerable difficulty with regard to reproducibility of the size of the infarcted region. In this study we have developed an experimental model which enables us to consistently produce focal regions of cerebral ischemia (resulting in infarction) which vary little in size in a number of animals. Thirty-seven cats (3-4 kg b. wt.) anesthetized with chloralose and urethane were used. Physiologic monitoring and adjustments maintained arterial blood values as follows: pCO2 27-35 Torr, pO2 100-150 Torr, pH +/- 7.4, glucose 200 mg%, hematocrit greater than 25. The left middle cerebral artery was exposed via a transorbital approach and occluded for 1-2 h with and without left and/or both carotid artery occlusion. Sixteen hours following the ischemic episode, the animals were sacrificed and sections of fresh brain tissue were processed for vital staining using 1% tetrazolium solution. With this method normal brain areas appear dark red, ischemic regions (without infarction) appear gray and irreversibly infarcted areas appear pinkish-white. The volumetric dimensions of the lesioned area were measured using a planimeter. The same tissue was also evaluated histologically by means of standard histopathologic techniques on paraffin-embedded material. Infarcted areas as delineated macroscopically by the tetrazolium correlated well with the light microscopic findings. Ten animals subjected to a 2-h occlusion of the left middle cerebral artery (LMCA) and both carotid arteries resulted in a reproducible infarct which was 3.2 +/- 0.7 ml in volume. This represents 13.3 +/- 2.9% of the total volume of both cerebral hemispheres (above the level of the inferior colliculus.(ABSTRACT TRUNCATED AT 250 WORDS)

Ganglioside-induced regeneration and reestablishment of axonal continuity in spinal cord-transected rats

In this study we examined the effect of chronic GM-1 ganglioside treatment on the reestablishment of axonal continuity and functional recovery in spinal cord-transected rats. Previous studies have shown that chronic treatment with GM-1 ganglioside is effective in producing regeneration of lesioned mesostriatal dopaminergic neurons in the central nervous system [1, 2]. In addition, GM-1 ganglioside advances peripheral nerve regeneration following nerve crush injury [12]. Axonal continuity was determined by the ability of the spinal cord to transport horseradish peroxidase across the region of transection. Comparisons between ganglioside-treated and saline-treated controls showed that ganglioside treatment resulted in the reestablishment of axonal continuity between the spinal cord distal to the level of the transection and the brainstem. Saline-treated controls showed little evidence of axonal continuity between these two regions. Thus gangliosides induce reestablishment of axonal continuity and thereby could advance functional recovery in rats following spinal cord transection.

Severe cerebral ischemia treatment by ventriculosubarachnoid perfusion with an oxygenated fluorocarbon emulsion.

Global hemispheric ischemia was produced in cats by bilateral carotid ligation and bleeding to a mean arterial pressure of 30 +/- 2 (SE) mm Hg. Total electrocerebral silence, as determined by computer-based power analysis, was obtained and maintained for 15 minutes. After this severe cerebral ischemic episode, the heparinized blood was reinfused and the carotid clamps were removed. After the cerebral ischemia, the ventriculosubarachnoid space was perfused with an oxygenated fluorocarbon nutrient solution (OFNS) or modified Elliotts B solution (ES) (control perfusion). The OFNS perfusate contained 400 to 640 mm Hg pO2 (produced by means of a bubble oxygenator pump system) as well as electrolytes, glucose, and amino acids, all of which are known to be important in cerebral metabolism. Flow rates of the perfusion were maintained at either 3 or 6 ml/minute and intracranial pressures were never permitted to exceed 10 mm Hg. During passage through the ventriculosubarachnoid space, oxygen, carbon dioxide, and electrolytes were exchanged between the brain and the OFNS perfusate. In addition, the OFNS perfusate was capable of picking up pCO2, lactate, and pyruvate. This produced a significant return of electrocerebral activity (P less than 0.01) and oxidative metabolism (P less than 0.01), as evidenced by a decline in the lactate/pyruvate ratio in the OFNS-treated cats, but not in nonperfused animals or those perfused with ES. In this study the ventriculosubarachnoid system served as an alternate vascular tree and enabled the perfusate to accomplish many of the functions of blood. Substantial penetration of the perfusate products into the brain occurred, enabling oxidative metabolism, removal of waste products, and electrocerebral activity to be reestablished.

Method and apparatus for tomographic diagnosis

A computer-assisted tomographic image is overlayed with the visual indication of any regions representing a deviation from a norm. The overlaid region may indicate a deviation of the radiodensity in that region. The overlaid region may also indicate a deviation from an electrophysiological norm based on compressed spectral analysis of an electroencephalographic signal or evoked potentials represented by such a signal.

Focal cerebral ischemia: reduction in size of infarcts by ventriculo-subarachnoid perfusion with fluorocarbon emulsion

A new method for brain resuscitation following acute focal ischemic insult has been developed in this laboratory. The technique utilizes a surrogate route to supply cerebral metabolites and employs highly oxygenated fluorocarbons (OFNS), which are efficient gas transport and exchange agents, perfused through the ventriculo-subarachnoid spaces. We previously described a return of aerobic metabolism and EEG after severe global ischemia by oxygenated perfusions and now report treatment-induced reduction in the size of experienced cerebral infarction. Twenty-eight cats were anesthetized (choralose and urethane), tracheotomized and placed in a stereotactic frame. Physiologic adjustments assured arterial blood pCO2 28-35 Torr, pO2 100-150 Torr pH 7.4 and glucose less than 200 mg%. The left middle cerebral artery was exposed transorbitally and temporarily clipped along with both common carotids for 2 h. One hour later (3 h after ischemic onset) the treated group were perfused by the ventriculo-cisternal route either with OFNS [pO2 = 600 Torr; 3 ml/min 6 h, 2 ml/min 2 h, 1 ml/min 2 h, 0.5 ml/min 2 h at 10 mm Hg intracranial pressure (ICP)] or with the vehicle perfusate. Eighteen to twenty hours after the ischemic insult the animals were sacrificed. Sections of fresh brain of 0.5 mm thickness were incubated in 1% triphenyl tetrazolium chloride. The infarcted areas were confirmed with classic neuropathologic techniques. Areas of infarction (expressed in cm3 and as % of the brain) were measured using a planimeter. OFNS-treated brains contained 80% less infarcted tissue than the vehicle-perfused or untreated stroked animals. The infarcted areas were significantly treatment reduced (P less than 0.05 ANOVA and Bonferroni tests).(ABSTRACT TRUNCATED AT 250 WORDS)

Giant basilar artery aneurysm presenting as a third ventricular tumor.

Giant aneurysm of the basilar artery presenting as a 3rd ventricular tumor is an unusual phenomenon. We are reporting a case in which a patient with a giant aneurysm of the basilar artery presented with symptoms of headaches and gait disturbance secondary to obstructive hydrocephalus. Although giant aneurysms presenting as mass lesions have been reported, the computed axial tomographic findings in our case were unique. Giant aneurysms of the basilar artery may be considered in the differential diagnosis of 3rd ventricular tumors.

Biopsy Diagnosis of Familial Alexander’s Disease

A 26-year-old woman presented with headaches, incoordination and a cerebellar mass (1982). The CT scan revealed dilated ventricles and a hypodense space-occupying lesion adjacent to the fourth ventricle. Neuronal loss, gliosis and masses of Rosenthal fibers were seen in biopsy. There was no evidence of neoplasm. A second biopsy 2 years later was similar to the original specimen. A diagnosis of Alexanders disease was suggested. Later that year the patients 11-year-old brother manifested a clinical picture initially diagnosed as brainstem glioma, but whose biopsy was characteristic of Alexanders disease. There has been a gradual deterioration of these siblings over the past 6 years (1986-1991). No evidence of neoplasm has appeared.

Preservation of neuronal function during prolonged focal cerebral ischemia by ventriculocisternal perfusion with oxygenated fluorocarbon emulsion.

The left middle cerebral artery and both carotid arteries of 17 cats were occluded to evaluate the effects of oxygenated fluorocarbon emulsion on brain ischemia. Carotid and middle cerebral arteries were occluded concurrently for 2 hours, followed by occlusion of the middle cerebral artery only for another 24 hours. Six animals were treated with oxygenated fluorocarbon emulsion delivered by ventriculocisternal perfusion, 5 received ventriculocisternal perfusion with mock cerebrospinal fluid, and 6 were untreated. Perfusions were started 3 hours after the initial ischemic insult. Infarct size judged by tetrazolium staining and standard neuropathological stains was significantly smaller in the treated animals. The mechanism of protection is as yet unknown, but most likely reflects oxygen/nutrient diffusion into the ischemic middle cerebral artery zone from the ventricular fluorocarbon, or removal of harmful metabolites. The results imply that ventriculocisternal perfusion with fluorocarbon emulsion can preserve neuronal function during a major cerebral vessel occlusion. In the cat, therapy is effective if begun within 3 hours after ischemia starts.

The effect of the prone position on venous pressure and blood loss during lumbar laminectomy

STUDY OBJECTIVE To determine the effects of three different prone support systems (Andrews spinal surgery frame, Cloward surgical saddle, and longitudinal bolsters) on inferior vena cava (IVC) and superior vena cava (SVC) pressures; the validity of measuring central venous pressure (CVP) for the determination of ideal positioning of the patient; and the relationship among frame type, blood loss, and hemodynamic measurements. DESIGN Prospective, randomized study of the hemodynamic effects of the prone position. SETTING Inpatient surgery at a university hospital (regional spinal cord injury treatment center). PATIENTS Eighteen patients free of significant coexisting disease (ASA physical status I and II) undergoing elective lumbar laminectomy. INTERVENTIONS Patients were assigned to one of three support frames and measurement of SVC pressure, IVC pressure, and mean arterial pressures (MAP) were obtained supine, prone, and after repositioning. These pressures and measured blood loss were obtained every 15 minutes during the surgical laminectomy portion of the procedure. MEASUREMENTS AND MAIN RESULTS Patients positioned on the Andrews frame had decreased mean SVC and IVC pressures from 8.7 mmHg and 8.4 mmHg in the supine position to 3.3 mmHg and 1.8 mmHg in the prone position, respectively (p less than 0.001). Prone position CVP also was significantly lower in the Andrews group compared with that in the other two groups (p less than 0.001). Repositioning efforts did not significantly decrease CVP. Blood loss was higher in the Cloward group (1,150 +/- 989 ml) than in the Andrews (245 +/- 283 ml) and bolsters (262 +/- 188 ml) groups (p less than 0.02). CONCLUSIONS Increased blood loss was not associated with increased SVC or IVC pressure, nor was there any significant correlation between any demographic or hemodynamic variable and blood loss. There was no evidence that CVP is useful in determining the ideal prone position in patients undergoing lumbar laminectomy.