PubMed Health⌕ Search

Biomedical subjects

F B Meyer

Publications and source records attributed to F B Meyer.

At least 55 records · Page 3Linked to original sources
PubMed1998

Fibromuscular dysplasia of the internal carotid artery associated with alpha1-antitrypsin deficiency.

OBJECTIVE: A deficiency of alpha1-antitrypsin has been implicated in the development of various disorders affecting medium-sized arteries, including intracranial aneurysms, cervicocephalic arterial dissections, and fibromuscular dysplasia (FMD). We performed alpha1-antitrypsin phenotyping in three consecutive patients who underwent bypass surgery for FMD of the extracranial internal carotid artery to test the hypothesis that alpha1-antitrypsin deficiency is a genetic risk factor for the development of FMD. METHODS: The study population consisted of three women (aged 37, 49, and 53 years, respectively) who had bilateral internal carotid artery stenosis caused by FMD. The indications for surgery included ocular or cerebral ischemic symptoms in two patients and progressive stenosis in one patient. The diagnosis of FMD was confirmed by histological examination of the resected segment of artery. The alpha1-antitrypsin phenotype was determined by isoelectric focusing in polyacrylamide gels. RESULTS: Two of the three patients had a heterozygous alpha1-antitrypsin deficiency (PiMZ phenotype). Pathological examination of the resected arterial segment showed typical medial FMD with focal intimal fibroplasia in both patients with the PiMZ phenotype. CONCLUSION: These findings suggest that a heterozygous alpha1-antitrypsin deficiency may be a genetic risk factor for the development of FMD of the internal carotid artery.

Adult↗
PubMed1998

Surgical treatment of spontaneous spinal cerebrospinal fluid leaks.

OBJECT: Spontaneous spinal cerebrospinal fluid (CSF) leaks are an increasingly recognized cause of intracranial hypotension and may require neurosurgical intervention. In the present report the authors review their experience with the surgical management of spontaneous spinal CSF leaks. METHODS: Between 1992 and 1997, 10 patients with spontaneous spinal CSF leaks and intracranial hypotension were treated surgically. The mean age of the seven women and three men was 42.3 years (range 22-61 years). Preoperative imaging showed a single meningeal diverticulum in two patients, a complex of diverticula in one patient, and a focal CSF leak alone in seven patients. Surgical exploration in these seven patients demonstrated meningeal diverticula in one patient; no clear source of CSF leakage could be identified in the remaining six patients. Treatment consisted of ligation of the diverticula or packing of the epidural space with muscle or Gelfoam. Multiple simultaneous spinal CSF leaks were identified in three patients. CONCLUSIONS: All patients experienced complete relief of their headaches postoperatively. There has been no recurrence of symptoms in any of the patients during a mean follow-up period of 19 months (range 3-58 months; 16 person-years of cumulative follow up). Complications consisted of transient intracranial hypertension in one patient and leg numbness in another patient. Although the disease is often self-limiting, surgical treatment has an important role in the management of spontaneous spinal CSF leaks. Surgery is effective in eliminating the headaches and the morbidity is generally low. Surgical exploration for a focal CSF leak, as demonstrated on radiographic studies, usually does not reveal a clear source of the leak. Some patients may have multiple simultaneous CSF leaks.

Adult↗
PubMed1998

Repair of carotid endarterectomy with a collagen-impregnated fabric graft.

UNLABELLED: Saphenous vein patch closure of carotid endarterectomies may decrease the risk of acute postoperative occlusion and recurrent stenosis. However, the disadvantages of a vein patch include postoperative rupture and pseudoaneurysm formation. OBJECT: The authors sought to assess the effectiveness of collagen-impregnated fabric grafts as substitutes for saphenous vein grafts. METHODS: In this report the authors prospectively analyzed 290 consecutive carotid endarterectomies in which a secondary closure was accomplished using a knitted double-velour graft. The 30-day major neurological morbidity and mortality rate was 1.7%. There were no postoperative occlusions or wound hematomas. The rate of recurrent carotid artery stenosis was less than 1%, and the graft site in one patient became infected. CONCLUSIONS: For surgeons who prefer a secondary closure of carotid endarterectomies, the synthetic graft may prove to be a viable alternative to a saphenous vein.

Blood Vessel Prosthesis↗
PubMed1998

Symptomatic pituitary metastases.

OBJECT: The diagnosis and treatment of metastasis to the pituitary gland can be difficult to determine. The goal of this study was to analyze the clinical presentation, treatment, and prognosis of patients who presented with symptomatic pituitary metastasis. METHODS: The cases of 36 patients with symptomatic pituitary metastases were reviewed. The most common primary cancers were breast (33%) and lung (36%). The presenting symptoms included diabetes insipidus, anterior pituitary insufficiency, and retroorbital pain. The overall median length of patient survival following diagnosis of pituitary metastasis was 180 days. In 20 patients (56%), symptoms stemming from pituitary metastasis were the first manifestation of illness. Local control of tumor was associated with significant improvement in survival times (p < 0.05) and amelioration of disabling symptoms including painful ophthalmoplegia and visual field deficits. CONCLUSIONS: Aggressive treatment including both surgical decompression and radiation therapy improves the quality of life in patients suffering from symptomatic pituitary metastasis.

Adult↗
PubMed1998

Primarily resected meningiomas: outcome and prognostic factors in 581 Mayo Clinic patients, 1978 through 1988.

OBJECTIVE: To establish prognostic factors for recurrence and outcome of surgical treatment, with or without postoperative radiation therapy, in patients with meningiomas. MATERIAL AND METHODS: From 1978 through 1988, 581 patients underwent initial resection of a previously untreated primary meningioma at Mayo Clinic Rochester. In this study cohort, the outcome and prognostic factors associated with radiographic progression-free survival were analyzed. RESULTS: Gross total resection (GTR) of the meningioma was accomplished in 80% of patients; the other 20% underwent less than GTR. Perioperative mortality within 10 days was 1.6%. Overall survival was significantly decreased from that for an age- and sex-matched cohort from the US white population. Progression-free survival at 5 and 10 years was 88% and 75%, respectively, in patients who underwent GTR and 61% and 39%, respectively, in those who underwent less than GTR. Multivariate analysis showed that age younger than 40 years, male sex, less than GTR, optic nerve involvement, and 4 or more mitotic figures per 10 high-power fields were associated with decreased progression-free survival. The 581 patients had 106 first recurrences. A trend toward improved progression-free survival was noted after first recurrence when irradiation with or without operation was used in comparison with only surgical treatment (P = 0.058). CONCLUSION: With only operative treatment of meningioma, the 10-year recurrence rate was 25% in patients who had GTR and 61% in those who had less than GTR. These results emphasize the need for long-term follow-up and for consideration of adjuvant radiation therapy. Patients treated at the time of recurrence seem to benefit from radiation therapy with or without surgical resection. Factors associated with recurrence were (1) less than GTR, (2) involvement of the anterior visual pathway, (3) age younger than 40 years, and (4) increased mitotic index.

Adolescent↗
PubMed1998

MR angiographic and sonographic indications for endarterectomy.

PURPOSE: Our objective was to determine whether appropriate criteria could be developed for performing an endarterectomy on the basis of sonographic and MR angiographic findings. METHODS: Fifty patients were examined prospectively with sonography, MR angiography, and conventional angiography. All three imaging studies were performed within 2 weeks of one another, and conventional angiography served as the reference standard. RESULTS: All 10 carotid occlusions were detected with sonography and MR angiography. Sonography accurately showed flow in two arteries, and MR angiography showed flow in one of three nearly occluded arteries with extremely slow flow. Multislab three-dimensional time-of-flight MR angiographic sequences underestimated the degree of stenosis in 12 arteries, and in two cases this resulted from high T1 signal within the atherosclerotic plaque. With conventional angiography as the reference standard for 70% to 99% stenosis, sonography had a sensitivity of 96%, a specificity of 91%, and a positive predictive value of 90%, while concordant sonographic findings and the presence of a signal void on multislab 3-D time-of-flight sequences had a sensitivity of 72%, a specificity of 98%, and a positive predictive value of 97%. CONCLUSION: Endarterectomy performed on the basis of sonographic findings of 70% to 99% stenosis and of a signal void on multislab 3-D time-of-flight MR angiographic sequences is appropriate.

Adult↗
PubMed1998

Anterior visual pathway meningiomas primarily resected between 1978 and 1988: the Mayo Clinic Rochester experience.

The relapse rate, overall survival, and factors associated with a decreased recurrence-free survival rate in patients with anterior visual pathway (AVP) meningioma were compared with these features in patients who had meningiomas at other sites. Management of these patients is discussed. A review of the records of 581 consecutive patients who had primary resection of meningiomas between 1978 and 1988 identified 43 patients with AVP meningioma. Multiple clinical, surgical, and pathologic factors at the initial examination were analyzed to assess their association with recurrence, and the patients who had AVP meningioma were compared with patients who had non-AVP meningiomas to determine the factors that may influence recurrence. Recurrence-free and overall survival rates were determined. The AVP tumors were associated with a higher rate of recurrence. Subtotal resection was more common in the AVP tumors, but it alone was not associated with the decrease in recurrence-free or overall survival rates. Several factors that may explain the higher recurrence rate in patients with AVP meningioma were identified. Anterior visual pathway meningioma is associated with a higher rate of recurrence than are meningiomas at other sites. Operation remains the mainstay of treatment for symptomatic nonseeing eyes. Radiation therapy seems to be effective for managing recurrent tumor.

Adolescent↗
PubMed1997

Carotid endarterectomy--indications, techniques, and Mayo Clinic experience.

Carotid endarterectomy is an effective surgical option for the prevention of stroke. However, the indications and risks associated with this procedure vary between individual surgeons and institutions. The aim of this review is to analyze the current indications for intervention and recent operative experience at a single institution, the Mayo Clinic. Recent trials are assessed and integrated with our management policy. Important aspects of anesthesia, monitoring, and operative technique are described along with rationale for their use. Outcome of patients operated on in the last 25 years is assessed with respect to grade. In the period from 1972 to 1995 there have been 3831 cases. Overall major morbidity and mortality is 1.8% for 3665 patients with primary stenosis. For 113 patients with recurrent stenosis it is 8.5%. Comparison with a previous interim review in 1986 demonstrates a modest improvement in the more recent cases. It is proposed that improvements in anesthesia and perioperative care are principally responsible for this improvement. The importance of institutional audit of results is emphasized because surgical morbidity is a major factor in decision-making.

Carotid Stenosis↗
PubMed1997

Endovascular treatment of ruptured posterior circulation aneurysms using electrolytically detachable coils.

The authors report their experience using electrolytically detachable coils for the treatment of ruptured posterior circulation aneurysms. Twenty-six patients with 28 posterior circulation aneurysms were treated. All patients were referred for endovascular treatment by experienced vascular neurosurgeons. Patients underwent follow-up angiography immediately after treatment, 1 to 6 weeks posttreatment, and 6 months posttreatment. Six-month follow-up angiograms obtained in 19 patients with 20 aneurysms demonstrated that 18 (90%) of the 20 aneurysms were 99 to 100% occluded, one aneurysm (5%) was approximately 90% occluded, and one aneurysm (5%) was approximately 75% occluded. The patient with the aneurysm that was approximately 75% occluded needed additional treatment, consisting of parent artery balloon occlusion, and was considered a treatment failure (3.8% of patients). There was one treatment-associated mortality (3.8%) but no treatment-associated serious neurological or nonneurological morbidity in the patient group. There was no recurrent aneurysm rupture during treatment or during the mean 27-month follow-up period. Endovascular treatment of ruptured posterior circulation aneurysms with electrolytically detachable coils can be accomplished with low morbidity and mortality rates. The primary goal of treatment--preventing recurrent aneurysm--can be achieved over the short term. Endovascular coil occlusion will play an important role in the treatment of ruptured posterior circulation aneurysms, particularly if long-term efficacy in preventing recurrent aneurysm hemorrhage can be documented.

Adult↗
PubMed1997

Resection of a large temporooccipital parenchymal arteriovenous fistula by using deep hypothermic circulatory bypass. Case report.

The authors believe this to be the first published case in which a deep hypothermic cardiopulmonary bypass was used to facilitate resection of a large parenchymal arteriovenous fistula. The use of this procedure facilitated resection of the lesion by allowing compression and manipulation of large venous varices that were overlying the deeper arterial feeding vessels. The surgical rationale, technique, and intra- and postoperative management are discussed.

Adult↗
PubMed1997

Intra-arterial thrombolysis in acute basilar artery thromboembolism: the initial Mayo Clinic experience.

OBJECTIVE: To investigate the feasibility of intra-arterial thrombolysis in acute basilar artery thrombosis. DESIGN: We reviewed a consecutive series of patients in whom intra-arterial thrombolysis was performed during the period from 1994 to 1996. MATERIAL AND METHODS: Intra-arterial thrombolysis with urokinase was done in an attempt to recanalize the basilar artery in a series of nine patients with basilar artery thrombosis admitted to the neurologic intensive care unit. At the time of initial assessment, all nine patients had major neurologic deficits attributable to brain-stem ischemia, including two patients with locked-in syndrome. RESULTS: Recanalization of the basilar artery system was successful in seven of the nine patients (a range of 2 to 13 hours after the ictus). Failure to recanalize the basilar artery occurred in two patients, who died after progressing to coma. Complete recovery or only minimal neurologic deficits were demonstrated in five of the nine patients. Despite recanalization of the basilar artery, two patients had no major change in their neurologic function, and both ultimately had severe ataxia and were fully dependent on others. A cerebellar hemorrhage occurred in one patient but without clinical worsening. Two patients had a retroperitoneal hematoma. CONCLUSION: Intra-arterial thrombolysis with urokinase in acute basilar artery occlusion resulted in recanalization in seven of the nine patients (78%). Five of the nine patients recovered fully, including two patients who had had locked-in syndrome. In light of the devastating natural course of acute basilar artery occlusion, these initial results are encouraging and indicate that intra-arterial thrombolysis may be a useful emergency treatment, even in patients with prolonged symptoms of ischemia (up to 12 hours).

Adult↗
PubMed1996

Nitric oxide synthase inhibition by L-NAME prevents brain acidosis during focal cerebral ischemia in rabbits.

This experiment examined the effects of nitric oxide (NO) synthase inhibition on brain intracellular pH, regional cortical blood flow, and NADH fluorescence before and during 3 h of focal cerebral ischemia using in vivo fluorescence imaging. Thirty fasted rabbits under 1% halothane were divided into four treatment groups receiving N omega-nitro-L-arginine methyl ester (L-NAME) intravenously at 20 min prior to ischemia (0.1, 1, and 10 mg/kg and 1 mg/kg + 5 mg/kg L-arginine) and two control groups (nonischemic and ischemic). In ischemic controls, brain pH(i), declined to 6.73 +/- 0.03 at 30 min and remained acidotic through the remainder of the ischemic period. In the 0.1 mg/kg group, brain pH(i) fell after 30 min of ischemia to 6.76 +/- 0.05 (p < 0.05), but then improved progressively despite occlusion. In the 1 mg/kg group, brain pH(i), remained normal despite middle cerebral artery (MCA) occlusion. In the 10 mg/kg group and in the combined L-NAME + L-arginine group, pH(i) fell after 30 min of ischemia to 6.81 +/- 0.03 (p < 0.05) and remained acidotic. During occlusion, regional cortical blood flow dropped in a dose-dependent manner. After 3 h of ischemia, regional cortical blood flow was 33.9 +/- 10.9 and 25.1 +/- 8.9 ml/100 g/min at doses of 0.1 and 10.0 mg/kg, respectively, L-NAME treatment did not significantly alter the increased NADH fluorescence that accompanied occlusion. This study shows that L-NAME can prevent intracellular brain acidosis during focal cerebral ischemia independent from regional cortical blood flow changes. This experiment suggests that NO is involved in pH(i) regulation during focal cerebral ischemia.

Acidosis↗
PubMed1996

Complications resulting from saphenous vein patch graft after carotid endarterectomy.

OBJECTIVE: Reducing surgical risks to the minimum in carotid endarterectomy has become crucial, especially with the results of recent clinical trials extending indications to asymptomatic patients. The use of the saphenous vein patch graft (SVPG) has been suggested to reduce early postoperative thrombosis and cerebral infarct as well as late recurrent stenosis. However, the exact risks and complications involved in this technique are not known. METHODS: During a 23-year period (1972-1994), 2888 carotid endarterectomies with SVPG for primary carotid stenosis were performed by the Neurosurgical Cerebrovascular Service at the Mayo Clinic. The data from all patients were retrospectively analyzed, emphasizing postoperative complications related to SVPG. RESULTS: There were five postoperative vein ruptures (0.17%), four cases of aneurysm formation, and three cases of deep infection necessitating surgical intervention. The vein patch ruptured in one male patient and four female patients (mean age, 69 yr). All ruptures occurred within 4 days of the primary operation, including two during the first 24 hours. All patients with rupture underwent emergency surgery and were found to have intact suture lines and tears in the middle of the grafts. Two patients recovered without deficits, one suffered major disability, and the other two died. Aneurysm of the patch developed in two male patients and two female patients (mean age, 71 yr). All of the patients developed painless pulsatile neck masses 1 to 9 years after the initial surgery; two also had recurrent ischemic symptoms. All of the patients with aneurysms underwent surgical correction without consequences. CONCLUSION: Although the benefit of routine use of SVPG in carotid endarterectomy is still the focus of debate, this analysis showed that its use adds a small but definite risk of serious complications related to inherent weakness of the venous tissue. If a surgeon chooses to use a patch graft, our recommendation is for use of a synthetic material rather than vein.

Aged↗
PubMed1996

Nitric oxide synthase inhibition by L-NAME during repetitive focal cerebral ischemia in rabbits.

The effects of nitric oxide synthase inhibition on brain acidosis, regional cortical blood flow (rCBF), and NADH redox state were examined using in vivo fluorescence imaging during four 15-min periods of moderate focal cerebral ischemia, each separated by three 5-min reperfusion periods followed by a final 3-h reperfusion period. Fasted rabbits under 1.5% halothane were divided into six groups of seven animals each: nonischemic controls, ischemic controls, and the following drug groups receiving NG-nitro-L-arginine methyl ester (L-NAME) intravenously 20 min before repetitive ischemia (as follows: 0.1 mg/kg, 1 mg/kg, 10 mg/kg, and 1 mg/kg + 5 mg/kg L-arginine). L-NAME at 0.1 and 1 mg/kg prevented the development of significant brain acidosis throughout the four ischemic insults. L-NAME at 10 mg/kg reduced preischemic rCBF by 21% (P < 0.05) and did not mitigate brain acidosis after the third and fourth ischemic insults. Brain intracellular pH returned toward baseline after the 3-h final reperfusion in all groups. NADH redox state was significantly (P < 0.05) elevated from baseline controls in all groups during the last three ischemic insults. During the final reperfusion period, NADH redox state returned toward baseline values only in the 0.1 mg/kg L-NAME and ischemic control group. In conclusion, low-dose L-NAME attenuated brain acidosis independent from rCBF changes during intermittent, moderate focal cerebral ischemia.

Animals↗
PubMed1996

Spontaneous spinal cerebrospinal fluid leaks and intracranial hypotension.

Spinal cerebrospinal fluid (CSF) leaks are often implicated as the cause of the syndrome of spontaneous intracranial hypotension, but they have rarely been demonstrated radiographically or surgically. The authors reviewed their experience with documented cases of spinal CSF leaks of spontaneous onset in 11 patients including their surgical observations in four of the patients. The mean age of the six women and five men included in the study was 38 years (range 22-51 years). All patients presented with a postural headache; however, most had additional symptoms, including nausea, emesis, sixth cranial-nerve paresis, or local back pain at the level of the CSF leak. All patients underwent indium-111 radionucleotide cisternography or computerized tomographic (CT) myelography. The location of the spontaneous CSF leak was in the cervical spine in two patients, the cervicothoracic junction in three patients, the thoracic spine in five patients, and the lumbar spine in one patient. The false negative rate for radionucleotide cisternography was high (30%). Subdural fluid collections, meningeal enhancement, and downward displacement of the cerebellum, resembling a Chiari I malformation, were commonly found on cranial imaging studies. In most patients, the symptoms resolved in response to supportive measures or an epidural blood patch. Leaking meningeal diverticula were found to be the cause of the CSF leak in four patients who underwent surgery. In three patients these diverticula could be ligated with good result but in one patient an extensive complex of meningeal diverticula was found to be inoperable. Two patients had an unusual body habitus and joint hypermobility, and two other patients had suffered a spontaneous retinal detachment at a young age. In conclusion, spontaneous spinal CSF leaks are uncommon, but they are increasingly recognized as a cause of spontaneous intracranial hypotension. Most spinal CSF leaks are located at the cervicothoracic junction or in the thoracic spine, and they may be associated with meningeal diverticula. The radiographic study of choice is CT myelography. The disease is usually self-limiting, but in selected cases our experience with surgical ligation of leaking meningeal diverticula has been satisfactory. An underlying connective tissue disorder may be present in some patients with a spontaneous spinal CSF leak.

Adult↗
PubMed1996

Giant intracranial aneurysm and fibromuscular dysplasia in an adolescent with alpha 1-antitrypsin deficiency.

Recent studies have suggested that a deficiency of alpha 1-antitrypsin may be a genetic risk factor for the development of intracranial aneurysms and arterial fibromuscular dysplasia. The authors report a 16-year-old girl with a history of lung disease who suffered a cerebral hemorrhage due to the rupture of a giant intracranial aneurysm arising from the middle cerebral artery. This fusiform aneurysm was associated with fibromuscular dysplasia of the intimal type. She was found to have an unusual alpha 1-antitrypsin deficiency (PiMP phenotype). This case provides further evidence of an underlying arteriopathy in alpha 1-antitrypsin deficiency.

Adolescent↗