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Biomedical subjects

R A Solomon

Publications and source records attributed to R A Solomon.

At least 109 records · Page 6Linked to original sources
PubMed1988

Surgical approaches to aneurysms of the vertebral and basilar arteries.

This report details the surgical treatment of 44 patients with aneurysms of the vertebral and basilar arteries. Three different surgical approaches were utilized depending on the location of the aneurysm. These were an anterior supratentorial approach, a lateral suboccipital approach, and a combined supratentorial and infratentorial approach along the petrous apex, with section of the lateral sinus and the tentorium. Using these operative exposures, aneurysms located anywhere on the vertebral-basilar arteries may be safely visualized and clipped. In this series, 1 patient died, 4 other patients had significant, long-lasting morbidity as a result of operation, and 32 patients returned to work and a normal life-style. These data support operative intervention under proper conditions and with selection of the correct exposures for the treatment of vertebral-basilar aneurysms.

Adult↗
PubMed1988

Early aneurysm surgery and prophylactic hypervolemic hypertensive therapy for the treatment of aneurysmal subarachnoid hemorrhage.

The prevailing sentiment of North American neurosurgeons is that there is no significant difference in overall morbidity between patients who are treated with early aneurysm surgery and those who are treated with delayed aneurysm surgery. This concept is based primarily on the high incidence of ischemic events after early intervention. Recent experience, however, indicates that prophylactic hypervolemic hypertensive therapy may be beneficial in reducing delayed ischemia after early aneurysm surgery. During the preceding 21 months, we have performed 125 operations for intracranial aneurysms. Fifty-six patients in this group presented less than 7 days after subarachnoid hemorrhage (SAH) (47 within 3 days) and were treated by a prospective protocol of urgent aneurysm surgery performed within 24 hours after presentation. In all cases, the aneurysm was clipped with the use of mannitol and spinal drainage for brain relaxation. All patients were then treated with prophylactic volume expansion therapy and induced hypertension with a central venous pressure or a Swan-Ganz catheter until the 14th day after SAH. Preoperatively, 17 patients were Hunt and Hess Grade I, 9 were Grade II, 28 were Grade III, and 2 were Grade IV. In this group of 56 patients at risk for delayed ischemia from vasospasm, 5 patients had significant intraoperative complications. Ten patients (18%) had delayed cerebral ischemia, totally reversible in 6 cases, with small infarcts in 3 cases, and with 1 death (2% mortality from delayed ischemia), there were 5 cases of shunted hydrocephalus, and 3 deaths from other complications. Overall, 41 patients (73%) returned to their premorbid occupations without neurological deficit.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1988

Unusual spinal cord enlargement related to intramedullary hemangioblastoma.

In a series of 60 intramedullary spinal cord tumors, there were eight cases of hemangioblastoma. Seven of these eight patients displayed evidence of diffuse spinal cord enlargement over multiple levels at a considerable range beyond the actual location of the tumor. One patient had a large intramedullary cyst that accounted for only part of the enlargement, and one had multiple tumor nodules. Six other patients had no obvious explanation for the diffuse cord enlargement. This phenomenon of extensive spinal cord enlargement appears to be unique to this type of tumor and not related to multiple tumors or extensive cyst formation. The cord enlargement seems to be related to edema and congestion of the spinal cord, perhaps secondary to the vascular shunt present in the hemangioblastomas. The possible pathophysiology and clinical importance of this observation is discussed.

Adult↗
PubMed1987

Current strategies for the management of aneurysmal subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) from a ruptured intracranial aneurysm represents a major health issue. Although most people who experience an aneurysmal SAH survive to be admitted to a hospital, less than one third of these patients ever return to their premorbid status. Clearly, morbidity of this magnitude demands reevaluation of the clinical approach to this problem. This article reviews the natural history of aneurysmal SAH, and examines the current therapeutic strategies that have been suggested to improve the outcome. Careful evaluation of the existing data suggests that early aneurysm surgery and aggressive postoperative volume expansion therapy constitute the best presently available approach to patients with ruptured intracranial aneurysms.

Antifibrinolytic Agents↗
PubMed1987

Regional cerebral metabolic activity in the rat following experimental subarachnoid hemorrhage.

A new experimental model was employed to investigate alterations of cerebral metabolic activity in rats subjected to extensive subarachnoid hemorrhage (SAH). The hemorrhages were produced in anesthetized animals by inserting 0.37 ml fresh autologous arterial blood into the subarachnoid space. Rats that underwent sham operations received subarachnoid injections of mock CSF to study the effects of sudden raised intracranial pressure (ICP). Forty-eight hours after subarachnoid injection, the unanesthetized rats were given intravenous injections of [14C]2-deoxyglucose. Experiments were terminated 45 min later by decapitation, and the brains were removed and frozen. Regional brain metabolic activity was studied employing quantitative autoradiography. In comparison with control animals, cerebral metabolic activity was diffusely decreased following SAH. Statistically significant decreases in metabolic activity of less than 34% were observed in 17 of 30 brain regions studied. The largest percentage reductions were in regions displaying the highest basal metabolic rates. Subarachnoid injections of mock CSF also produced depression of cerebral metabolic activity, but quantitatively these changes were not as pronounced as in the hemorrhage group. These studies demonstrate regional changes in brain function following SAH. The data relate these changes to both the presence of blood in the subarachnoid space and sudden raised ICP.

Animals↗
PubMed1987

Intramedullary melanotic schwannoma of the cervicomedullary junction.

We report a case of a patient with an intramedullary tumor of the cervicomedullary junction. At operation, the tumor was noted to be highly pigmented, and pathological study demonstrated that the tumor was a melanotic schwannoma. Both intramedullary schwannomas and melanotic schwannomas in any location in the body are exceedingly rare. This is the first reported case of an intramedullary melanotic schwannoma of the central nervous system. The possible origin of this tumor is discussed.

Aged↗
PubMed1987

Interhemispheric approach for the surgical removal of thalamocaudate arteriovenous malformations.

A series of 250 surgically treated cerebral arteriovenous malformations (AVM's) is presented, in which 22 lesions were located primarily in the thalamus and caudate nucleus. A standardized interhemispheric approach through the posterior corpus callosum and into the atrium of the lateral ventricle was utilized for the surgical removal of these AVM's. Total removal was confirmed by angiography in 18 patients; removal was subtotal in four cases. There were no deaths in this group of patients. Disturbances of recent memory pre- and postoperatively were seen in half of the patients, but most of these deficits were temporary. Other complications included: postoperative homonymous hemianopsia (six cases), transient hemiparesis (three cases), hemisensory loss (two cases), Parinaud's syndrome (one case), and recurrent hemorrhage 2 years after surgery (one case). All 22 patients returned to their previous occupations and are leading independent lives. The results of this experience indicate that thalamocaudate AVM's can be effectively treated by resection.

Adolescent↗
PubMed1986

Increased norepinephrine synthesis in the cerebral hemispheres of rats following subarachnoid hemorrhage.

Norepinephrine (NE) was assayed in rat brains 72 h after the creation of an experimental subarachnoid hemorrhage (SAH). NE in the cerebral hemispheres was found to increase by 64% when compared to controls. NE in the brainstem and cerebellum was unchanged. The kinetics of hemispheric NE metabolism were then studied in control and SAH rats. SAH caused a 3-fold increase in NE synthesis and a 44% reduction in turnover time when compared to controls. These results may reflect increased activity of central noradrenergic neuronal pathways in SAH.

Animals↗
PubMed1986

Surgical management of arteriovenous malformations that follow the tentorial ring.

In a series of 200 intracranial arteriovenous malformations (AVMs) treated surgically, 33 malformations were situated very close to the tentorial incisura. All but one of these AVMs were totally removed. Four operative approaches were utilized in this group of patients: an interhemispheric approach for lesions of the medial hemispheres, splenium of the corpus callosum, and posterior 3rd ventricle; a subtemporal approach to the inferior and medial temporal lobe; a supracerebellar-infratentorial approach to anterodorsal cerebellum and quadrigeminal regions; and a subtemporal transtentorial exposure to the dorsolateral mesencephalon. There were no surgical deaths. Three patients had unsatisfactory outcomes. Our experience with this series indicates that deep cerebral AVMs in the region of the tentorial incisura may be safely removed if there is proper selection of operative approach and attention to surgical technique.

Adolescent↗
PubMed1986

Elevation of brain norepinephrine concentration after experimental subarachnoid hemorrhage.

Regional brain tissue catecholamine concentrations were measured in 5 control rats and in 10 rats 72 hours after experimental subarachnoid hemorrhage (SAH). Catecholamine levels were determined in the cerebral hemispheres, brain stem, and cerebellum of each animal using a radioenzymatic assay. Three days after SAH, the tissue concentration of norepinephrine (NE) in the cerebral hemispheres was 64% greater than that in control rats (P less than 0.001). NE levels did not change significantly in either the brain stem or the cerebellum. Most if not all of the NE in the brain tissue rostral to the brain stem is derived from neurons that originate in the locus coeruleus (LC). These data may therefore indicate that the LC is activated after SAH. The possible pathophysiological consequences of activation of the LC in relation to delayed cerebral ischemia after SAH will be discussed.

Animals↗
PubMed1986

Incidence and etiology of intracerebral hemorrhage following carotid endarterectomy.

In a consecutive series of 1930 carotid endarterectomies there were eight cases of postoperative intracerebral hemorrhage. One of these patients was operated on 2 weeks following cerebral infarction and had severe uncontrollable hypertension after surgery. A second patient had an intraoperative embolus and bled while fully heparinized on the 3rd postoperative day. Only one patient in the series bled into an area of documented cerebral infarction. The remainder of the cases represented hemorrhage into essentially normal brain. Seven of the eight patients with intracerebral hemorrhage had high-grade internal carotid artery stenosis preoperatively. Although several factors have contributed to the brain hemorrhages in this series of patients, postoperative cerebral hyperperfusion which often follows endarterectomy may have played an important role. Defective cerebrovascular autoregulation in chronically ischemic brain regions may predispose patients to intracerebral hemorrhage after removal of a high-grade stenosis of the internal carotid artery.

Aged↗
PubMed1986

Management of arteriovenous malformations of the brain stem.

In a series of 250 intracranial arteriovenous malformations (AVM's), 12 malformations involved the brain stem. Nine of these lesions were treated surgically, with complete obliteration in eight. There were no operative deaths, and only two patients were made worse by surgery. In the nonsurgically treated group, one patient had embolization therapy and two patients underwent radiation therapy. Results in these three patients have not been satisfactory. These data indicate that brain-stem AVM's can be surgically removed with acceptable morbidity.

Adolescent↗
PubMed1984

Defective cerebrovascular autoregulation in regions proximal to arteriovenous malformations of the brain: a case report and topic review.

We report the case of a patient with a large left subfrontal arteriovenous malformation (AVM) that was supplied by the right internal carotid artery. The anomalous blood supply developed because of complete occlusion of the left internal carotid artery. When the AVM was removed, the patient experienced a hemorrhage into the right basal ganglia. The possibility that this hemorrhage was related to a defect of autoregulation in blood vessels that lie proximal to a large AVM is discussed. Even though this is a unique case, the pathophysiological events that are documented are relevant to the preoperative preparation and surgical management of all patients with AVMs.

Carotid Artery Diseases↗
PubMed1984

Depression of circulating blood volume in patients after subarachnoid hemorrhage: implications for the management of symptomatic vasospasm.

The result of 42 blood volume determinations made with autologous red blood cells labeled with chromium-51 are reported. The subjects consisted of 11 control patients and 25 patients with recent subarachnoid hemorrhage (SAH). The mean red blood cell volume (RBCV) and the total blood volume (TBV) for female patients after SAH were significantly lower than corresponding control values (P less than 0.01). No depression of blood volume was found in males as a group. Seventy-two per cent of females had below-normal RBCV and 50% had below-normal TBV. Fifteen patients demonstrated angiographic vasospasm or signs of cerebral ischemia. Only 1 patient with asymptomatic vasospasm had a below-normal RBCV or TBV, whereas 6 of 7 patients with symptomatic vasospasm had a subnormal RBCV or TBV. The mean RBCV and mean TBV for female patients with symptomatic vasospasm were significantly lower than corresponding control values (P less than 0.02) and lower than values for female patients with asymptomatic vasospasm (P less than 0.05). The data suggest that volume status may be the important differential between asymptomatic and symptomatic vasospasm. Delayed ischemic deficits can be expected to develop in patients who have both spasm of the intracranial vessels and decreased TBV. Patients with normal blood volume are far less likely to experience cerebral ischemia, even if vasospasm develops.

Adult↗
PubMed1980

Reduction of postoperative pain and narcotic use by transcutaneous electrical nerve stimulation.

Transcutaneous electrical nerve stimulation (TENS) was evaluated as a postoperative analgesic. Patients undergoing lumbar spine operations, hip surgery, and gynecological laparotomies were studied. Sterile electrodes, placed near the incision immediately after operation, were connected to a continuously operating stimulator for 48 hours after operation. Results from 46 experimental patients demonstrated that TENS could reduce the demand for postoperative narcotics in a group of patients who had not used narcotic analgesics before operation. No significant benefit was observed for patients who had used narcotics prior to operation.

Analgesia↗