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  • Author or Editor: Thoralf M. Sundt Jr x
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Benjamin R. Gelber and Thoralf M. Sundt Jr.

✓ Ten patients with intracranial internal carotid artery (ICA) aneurysms were managed by combining ICA ligation with an extracranial to intracranial bypass procedure. Nine of these grafts were proven patent by angiogram. One patient was unable to return for postoperative angiograms; his graft had appeared patent on physical examination. Seven aneurysms were intracavernous, two were giant carotid-ophthalmic aneurysms, and one aneurysm was at the intracranial bifurcation of the ICA. Despite occlusion cerebral blood flow (CBF) measurements of 20 ml/100 gm/min or less in six patients, only one patient was unable to tolerate ICA ligation. Three patients developed transient aphasia, but there were no permanent neurological deficits associated with the carotid occlusion. Seven patients had improvement in pre-existing extraocular palsies or visual field defects. Others remained stable.

The combination of an extracranial to intracranial microvascular bypass procedure with ICA ligation seems to be an effective method of treatment for aneurysms near the base of the skull that cannot be obliterated by a direct intracranial approach. The addition of the bypass procedure permits ICA ligation in patients who would not otherwise have tolerated occlusion of that vessel. Intraoperative xenon CBF measurements are an important adjunct to the operation.

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Mitchell R. Smigiel Jr. and Thoralf M. Sundt Jr.

✓The comparative effectiveness of isoproterenol (Isuprel), phentolamine (Regitine), and phenoxybenzamine (Dibenzyline) in modifying basilar arterial spasm induced by the topical application of arterial blood was studied in cats. None of these agents was effective in inhibiting initial peak constriction. Each reduced the duration of the vasospasm. The results indicate that both alpha-blockade and beta-stimulation can alter the course of blood-induced cerebral vasospasm.

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Phyo Kim, Thoralf M. Sundt Jr. and Paul M. Vanhoutte

✓ To investigate the alteration of endothelium-dependent responses in chronic vasospasm after subarachnoid hemorrhage (SAH), experiments were carried out in the double-hemorrhage canine model. After the presence of vasospasm was confirmed by cerebral angiography on Days 0 and 7, pharmacological studies on the basilar artery were conducted in vitro on Day 8. In the SAH group, endothelium-dependent relaxation was abolished in response to arginine vasopressin and was significantly reduced in response to thrombin. Endothelium-independent relaxation in the SAH group was preserved in response to papaverine and was minimally reduced in response to sodium nitroprusside. Endothelium-dependent contraction in response to arachidonic acid, acetylcholine, the calcium ionophore A23187, adenosine diphosphate, mechanical stretching, and hypoxia persisted in the SAH group. The maximal contraction to KCl and uridine triphosphate, which is endothelium-independent, was diminished in the SAH group, but no changes in sensitivity were noted in the concentration-response relationships. A significant correlation was observed between the degree of vasospasm determined angiographically and the loss of endothelium-dependent relaxation. The loss of endothelium-dependent relaxation and the persistence of endothelium-dependent contraction suggest that the deterioration in the endothelium-dependent responses may be an important component in the pathogenesis of cerebral vasospasm.

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Phyo Kim, Thoralf M. Sundt Jr. and Paul M. Vanhoutte

✓ The purpose of this study was to examine the hypotheses that structural stiffening of the arterial wall contributes to chronic cerebral vasospasm, and that alteration in properties of smooth muscle takes place after subarachnoid hemorrhage (SAH). Subarachnoid hemorrhage and subsequent chronic vasospasm were induced in dogs by two cisternal injections of autologous blood (on Day 0 and Day 2). Vasospasm was confirmed by angiography performed on Day 0 and Day 7. Animals in the control group underwent angiography only. On Day 8, the mechanical properties of the basilar arteries were studied in vitro. Passive compliance, measured under total inhibition of spontaneous myogenic tone with diltiazem (10−4 M) plus papaverine (10−4 M) was smaller in the SAH group. The length-contraction curve was shifted to the left and the optimum length for maximum contraction (Lmax) was significantly shorter in the spastic blood vessels. The spontaneous myogenic tone was augmented in the SAH group, resulting in an increase in resting tension at each length. By contrast, the maximum contractions in response to KCl and uridine 5′-triphosphate were markedly reduced in the SAH group, without changes in sensitivity to these agents. These differences in mechanical properties were observed in rings both with and without endothelium. The results indicate that, in chronic vasospasm, stiffening of the noncontractile component of the vasculature takes place as well as alterations in the contractile component, both of which presumably contribute to the shift in resting length-tension relationship and length-contraction relationship of the artery. The decreased distensibility, the increase in resting tension, and the shortening of the Lmax all favor a smaller diameter of the artery after SAH, possibly contributing to vasospasm.

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Thoralf M. Sundt Jr., Burton M. Onofrio and John Merideth

✓ Initial experience with intravenously administered isoproterenol and lidocaine hydrochloride in 14 patients with severe spasm from subarachnoid hemorrhage is summarized. All patients were actively deteriorating from progressive spasm without other major complications; 12 of 14 improved, and two died. The method of treatment, results, and rationale for this method of therapy are discussed.

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Robert E. Anderson, Alice M. Bowron and Thoralf M. Sundt Jr.

✓ A combination of the Sundt-Kees reinforcing aneurysm clip applied to a Drake aneurysm clip in a piggyback fashion was studied for possible defects due to corrosion and or tissue toxicity. These two clips, which are made of similar metal (301 stainless steel), showed little or no defects when immersed in 5% saline or when implanted in rats for 6 months. This study demonstrates that clips made of similar metals can be used piggyback in patients without ill effects provided that they are carefully handled to avoid any abrasion or misbends which could conceivably lead to corrosion.

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W. Richard Marsh, Robert E. Anderson and Thoralf M. Sundt Jr.

✓ The adverse effect of a minimal cerebral blood flow (CBF) in models of global ischemia has been noted by many investigators. One factor believed important in this situation is the level of blood glucose, since a continued supply of this metabolite results in increased tissue lactate, decreased brain pH, and increased cell damage. The authors have extended these observations to a model of focal incomplete ischemia. Brain pH was measured in fasted squirrel monkeys in regions of focal incomplete ischemia after transorbital occlusion of the middle cerebral artery (MCA). In both control and hyperglycemic animals, CBF was reduced to less than 30% of baseline. At 3 hours after MCA occlusion, brain pH in the control group was 6.66 ± 0.68 as compared to 6.27 ± 0.26 in the glucose-treated group. This difference was statistically significant by Student's unpaired t-test (p < 0.05). Thus, hyperglycemia results in decreased tissue pH in regions of focal incomplete cerebral ischemia in monkeys.

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John D. Michenfelder, Roy F. Cucchiara and Thoralf M. Sundt Jr.

✓ Because of a suspicion that intraoperative penicillin antibiotics might be causing early postoperative seizures in craniotomy patients, a deliberate effort was initiated in 1987 to avoid these agents in favor of nonpenicillin antibiotics. This permitted a retrospective comparison of the incidence of early postoperative seizures in craniotomy patients who did and who did not receive intraoperative penicillins. Records of patients treated between July 1, 1984, and July 1, 1985, and between July 1, 1987, and July 1, 1988, were reviewed, for a total of 1316 procedures. There were no seizures in the 323 patients who underwent suboccipital craniectomy. However, among the 993 patients receiving supratentorial procedures there were 30 with seizures within the first 6 hours postoperatively, 19 of which were generalized seizures. The incidence of early seizures was 4.7% (20 cases) of the 427 patients given penicillins and only 1.8% (10 cases) of the 566 not given penicillins (p < 0.01). Since patients undergoing surgery for intractable seizures have a high incidence of early postoperative seizures (11 of 92 in this series, or 12%), creation of a subgroup eliminated these from consideration but did not alter the relationship of penicillins to early seizures (p < 0.02). The authors conclude that intraoperative (and early postoperative) penicillin antibiotic administration should be avoided, if possible, in patients undergoing craniotomy for supratentorial pathology.

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Douglas Chyatte, Nicolee C. Fode and Thoralf M. Sundt Jr.

✓ The management results in 244 patients admitted to one institution within 3 days of aneurysmal subarachnoid hemorrhage (SAH) from January, 1979, to December, 1985, were analyzed with respect to the timing of surgical intervention. Twenty-six patients died prior to surgery. Patients surviving to surgery were divided into three groups according to the interval between preadmission SAH and surgery: 0 to 3 days (85 cases), 4 to 9 days (83 cases), and 10 or more days (50 cases). Of the patients who were categorized neurologically into Botterell Grades 1 and 2 (Hunt and Hess Grades I to III) on admission, 87% had an excellent or good result on follow-up evaluation. Patients undergoing surgery 0 to 3 days after SAH had a statistically significant increase in the incidence of postoperative ischemic symptoms (p < 0.005), which was balanced by similar complications preoperatively in the 10-day post-SAH surgical group. Most rebleeds occurred before admission but delaying surgery did increase the risk of rebleeding in the hospital (p < 0.0005). Management morbidity and mortality occurred primarily as a direct result of a severe initial hemorrhage; thus, the measured benefits of early surgery were less than might have been predicted.