Michael B. Pritz

Treatment of Patients with Neurological Deficits Associated with Cerebral Vasospasm by Intravascular Volume Expansion

Four patients, including one preoperative patient, developed neurological deficits associated with angiographically proven cerebral vasospasm and were treated with intravascular volume expansion. Indicator dilution techniques were employed to monitor intravascular volume and cardiac functions during treatment. All four patients improved promptly. None of the patients developed cardiac or pulmonary dysfunction despite marked increase in intravascular volume and despite several risk factors such as cardiac symptoms, electrocardiographic abnormalities, and advanced age. The techniques of monitoring and controlling intravascular volume are described. We believe that this is an important therapeutic adjunct for certain aneurysm patients.

Treatment of patients with neurological deficits associated with cerebral vasospasm by intravascular volume expansion

Four patients, including one preoperative patient, developed neurological deficits associated with angiographically proven cerebral vasospasm and were treated with intravascular volume expansion. Indicator dilution techniques were employed to monitor intravascular volume and cardiac functions during treatment. All four patients improved promptly. None of the patients developed cardiac or pulmonary dysfunction despite marked increase in intravascular volume and despite several risk factors such as cardiac symptoms, electrocardiographic abnormalities, and advanced age. The techniques of monitoring and controlling intravascular volume are described. We believe that this is an important therapeutic adjunct for certain aneurysm patients.

Vertebral artery disease: Radiological evaluation, medical management, and microsurgical treatment

The neuroradiological evaluation, perioperative medical management, and microsurgical treatment of variously located vertebral artery lesions are presented. Four types of surgical procedures were undertaken: proximal vertebral artery to common carotid artery end-to-side anastomosis; external carotid artery to midcervical vertebral artery end-to-side anastomosis; external carotid artery to distal cervical vertebral artery end-to-end anastomosis; and occipital artery to posterior inferior cerebellar artery end-to-side anastomosis. Each case is used to demonstrate the evaluation and management involved, the type of and rationale for the surgical procedure selected, and the patency of the anastomosis performed. Two points are emphasized. One is that, after careful angiographic evaluation and improved perioperative medical management, lesions of the vertebral artery are indeed amenable to microsurgical intervention with relatively low risk to the patient. The other is that, whenever possible, anastomosis of the largest caliber of vessels with the least number of suture lines is the surgical treatment of choice.

Succinate dehydrogenase activity in the telencephalon of crocodiles correlates with the projection areas of sensory thalamic nuclei

Telencephalic auditory and visual regions in crocodiles have been identified by following the course and distribution of degenerating axons that result from stereo-taxic lesions of certain neuronal aggregates in the thalamus. One such area, nucleus reuniens pars centralis, which receives bilateral auditory input from the central nucleus of the torus semicircularis 7, projects to a caudomedial portion of the dorsal ventricular ridge 8. Another diencephalic region, nucleus rotundus, which receives bilateral visual afferents from the optic rectum 2, projects to an anterolateral portion of the dorsal ventricular ridge 0. Furthermore, the dorsal ventricular ridge of crocodiles, as well as that of other reptiles and birds, shares certain properties in common with neocortical areas in mammals 5,10. In fact, some have suggested that the dorsal ventricular ridge of birds and reptiles is homologous to certain neocortical areas in mammals 5. Regardless of its similarities with mammalian neocortex, the dorsal ventricular ridge of crocodiles merits study because it is the highest sensory integration center in this group of reptiles. Unfortunately, distinct cyto-and myeloarchitectonic properties which readily distinguish auditory and visual regions in the midbrain 7 and thalamus7, 9 of Caiman could not be demonstrated in the dorsal ventricular ridgeS,L While subdivisions of the dorsal ventricular ridge have been identified in crocodiles 1~,12, they do not correspond precisely with the distribution of sensory thalamic efferents in the telencephalon of Caiman s,9. Thus, an approach based on properties other than cyto-or myeloarchitec-ture was sought. The importance of the identification of such sensory areas in the dorsal ventricular ridge of Caiman is 3-fold. First, since small thalamic lesions were made in previous experiments 8,9, damage to nucleus reuniens pars centralis and to nucleus rotundus was subtotal. Consequently, only a portion of each respective telencephalic projection area was identified. Thus, a technique that would correlate with the telencephalic projection areas of these thalamic nuclei might demonstrate the full extent of these regions in the dorsal ventricular ridge. Second, the ability to determine such areas in descriptive material might allow similar identification in other planes of section, e.g. sagittal, which

Parallels in the Organization of Auditory and Visual Systems in Crocodiles

Vertebrates are thought to have had a unimodal origin; that is, they are thought to have arisen only once in time (Romer, 1966). Therefore, all vertebrate nervous systems should exhibit certain features in common which reflect their common genetic inheritance. Indeed, at a certain level of examination this appears to be the case. Thus all vertebrate brains that have been examined reveal the same gross brain regions: prosencephalon, mesencephalon, and rhombencephalon. Furthermore, additional subdivisions such as the telencephalon and optic tectum can readily be identified in all vertebrates. Soon, however, a point is reached where clear-cut divisions are not obvious. For example, the dorsal division of the lateral geniculate nucleus, which is easily identified in many mammals because of its striking pattern of lamination, may or may not be present in other vertebrate classes. Therefore, one task for comparative vertebrate neuroanatomy is to identify and describe which neuronal aggregates and neural circuits are or are not present in various vertebrates. This approach, which will document similarities as well as differences, requires comparison of similar findings not only in other members of a particular class but also in species in other vertebrate classes. In this manner, similarities may reveal basic features of neural organization common to all vertebrate central nervous systems whereas differences may reveal important aspects or trends in the evolution of vertebrate nervous systems.

Carotid endarterectomy after recent stroke: preliminary observations in patients undergoing early operation

Three patients with recent stroke underwent carotid endarterectomy 1, 4, and 8 days after the onset of maximal symptoms. In each case, computed tomography (CT) demonstrated recent cerebral infarction and cerebral arteriography showed high grade cervical carotid stenosis. No patient developed worsened neurological symptomatology, intracerebral hemorrhage, or vasomotor paralysis. These results suggest that carotid endarterectomy, if indicated, can be performed safely after acute stroke under certain conditions. These criteria include the following: normal level of consciousness, relatively small cerebral infarction without mass effect on CT, and meticulous control and monitoring of systemic blood pressure during the perioperative period. These initial observations suggest that a specific subgroup of patients with recent cerebral infarction may be able safely to undergo carotid endarterectomy shortly after diagnosis.

Evaluation and treatment of aneurysms of the vertebral artery: different strategies for different lesions.

Aneurysms of the vertebral artery and its branches are relatively uncommon lesions. Their anatomy and presentation can be quite variable. A spectrum of aneurysms of the vertebral artery is presented to illustrate the neuroradiological evaluation, surgical treatment, and perioperative management of these complex lesions.

Transient neurologic deficits associated with congestive heart failure and hypovolemia

This report describes a patient in whom symptoms of vertebrobasilar insufficiency were associated with the extremes of hydration—congestive heart failure and hypovolemia. In each instance, reversal of neurologic deficits was correlated with correction of the underlying problem.