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Biomedical subjects

N A Martin

Publications and source records attributed to N A Martin.

At least 91 records · Page 5Linked to original sources
PubMed1989

Venous rupture during transvenous approach to a carotid-cavernous fistula. Case report.

An attempt at transfemoral transarterial balloon occlusion of a high-flow spontaneous carotid-cavernous fistula was unsuccessful because the carotid artery rent was too small for this approach. During a subsequent transvenous approach to the cavernous sinus through the jugular vein, the inferior petrosal sinus was perforated. A minor subarachnoid hemorrhage occurred before the tear could be sealed by the deposition of three Gianturco coils in the vein. The patient was taken to the operating room for emergency obliteration of the fistula and petrosal sinus in order to remove the risk of further hemorrhage. Under the guidance of intraoperative digital subtraction angiography, isobutyl-2-cyanoacrylate was injected directly into the surgically exposed cavernous sinus. Successful obliteration of the fistula was achieved with preservation of the carotid artery, and the angiography catheter was removed safely from the petrosal sinus. Although initially after surgery the patient had nearly complete ophthalmoplegia, at her 1-year follow-up examination she had normal ocular motility and visual acuity. The transvenous approach to the cavernous sinus and alternative methods of treatment of carotid-cavernous fistulas are discussed.

Aged↗
PubMed1988

The pathology of encephalic arteriovenous malformations treated by prior embolotherapy.

A pathologic study was undertaken of seven encephalic arteriovenous malformations, including five resected from one to seven days after balloon embolization, one resected 10 days after embolization with polyvinyl alcohol foam (PVA), and a large mesencephalic AVM in a patient who died eight weeks after a series of embolization procedures with PVA and silicone spheres. AVM's resected 6-7 days following balloon embolization showed focal mural and adventitial inflammatory infiltrates and parenchymal (i.e. non-vascular) necrosis of a large portion of one AVM. The AVM examined 7 days post-balloon embolization showed an intraluminal thrombus containing refractile particles surrounded by foreign body giant cells (FBGC's). The AVM removed 10 days after PVA embolotherapy showed mural and perivascular necrosis with infiltration by polymorphonuclear leukocytes. The single autopsy case showed FBGC's surrounding residual PVA, refractile particles deep within vascular walls, and marked mural thickening of AVM channel walls, changes that may represent a response to previous angionecrosis and inflammation at the time of embolization. These findings, the pathogenesis of which is discussed in detail, may help to explain some of the rare complications of iatrogenic embolotherapy with these materials, as well as providing evidence for the basis of their efficacy.

Adult↗
PubMed1988

Comparative transoral dural closure techniques: a canine model.

A watertight dural closure is difficult to achieve after transoral-transclival operation for ventral intradural lesions at the craniocervical junction. These procedures have a high morbidity and mortality from cerebrospinal fluid (CSF) fistula, meningitis, and abscess. We used a canine model to test three different techniques of dural closure after transoral intradural operation: primary suture closure, laser patch weld, and fibrin glue patch closures. The primary suture closure technique was inadequate. All eight leaked CSF at the time of operation, and five had radiographic leaks and were incompetent at autopsy. All seven of the laser closures leaked CSF at operation, yet only one was incompetent at autopsy. The fibrin glue technique was superior and provided a solid seal at operation, even with repeated Valsalva maneuvers to 40 mm Hg. The immediate and persistent seal at operation is clinically significant because it may prevent CSF leak, meningitis, and abscess formation in human patients after transoral surgery. Fibrin glue is excellent for repairing complex dural defects and merits evaluation in clinical trials.

Animals↗
PubMed1988

Middle cerebral artery aneurysm due to Nocardia asteroides: case report of aneurysm excision and extracranial-intracranial bypass.

Nocardia asteroides is an uncommon human pathogen typically encountered in immunocompromised patients. Primary central nervous system (CNS) nocardiosis is rare and usually manifests as cerebritis or abscesses. The case of a young woman who presented with CNS Nocardia abscesses complicated by an infective middle cerebral artery aneurysm is reported. Treatment, which included abscess aspiration, aneurysm excision, and end-to-end extracranial to intracranial bypass and prolonged antibiotic therapy, resulted in an excellent outcome. This case and the management of CNS nocardiosis are reviewed.

Adult↗
PubMed1987

Multiple intracranial aneurysms due to Coccidioides immitis infection. Case report.

True mycotic (fungal) aneurysms are distinctly uncommon. The case of a young woman with multiple intracranial aneurysms of Coccidioides immitis origin is presented. Coccidioides immitis organisms are not uncommon central nervous system pathogens and usually cause basilar meningitis and hydrocephalus. There are no previous reports of a coccidioidal mycotic aneurysm. The management of intracranial coccidioidomycosis and fungal aneurysms is reviewed.

Adult↗
PubMed1987

Vertebrobasilar insufficiency. Part 1: Microsurgical treatment of extracranial vertebrobasilar disease.

Extracranial vertebrobasilar artery thrombo-occlusive disease may cause repetitive transient ischemic episodes and, less frequently, brain-stem or cerebellar infarction. This report describes 40 patients who experienced repetitive vertebrobasilar ischemic symptoms despite maximal medical therapy. The natural history, pathogenesis, and treatment options for each causative lesion are reviewed. The operative approaches to symptomatic disease of the proximal vertebral arteries, arterial compression by cervical osteophytes, traumatic lesions of the vertebral arteries, and thrombo-occlusive pathology of the distal extracranial vertebral arteries are outlined. Specific anesthetic and surgical techniques that have proved successful while achieving zero operative mortality and low perioperative morbidity rates are reported.

Adolescent↗
PubMed1987

Vertebrobasilar insufficiency. Part 2. Microsurgical treatment of intracranial vertebrobasilar disease.

Posterior circulation transient ischemic attacks have an associated risk of subsequent infarction of approximately 5% per year. Intracranial vertebrobasilar thrombo-occlusive lesions appear particularly likely to result in repetitive ischemic symptoms and in infarction due to hemodynamic insufficiency. The authors present their experience with 45 patients with symptomatic intracranial vertebrobasilar vascular disease despite maximal medical therapy. The specific operative approaches for intracranial vertebral artery endarterectomy and extracranial to intracranial posterior circulation revascularization procedures are outlined.

Adult↗
PubMed1987

Surgical management of large AVM's by staged embolization and operative excision.

A series of 20 patients with giant arteriovenous malformations (AVM's) managed with staged embolization and surgical resection is presented. Complete excision was accomplished in 18 of these patients. There were no deaths and only three complications, of which one was disabling. Further evidence for the presence of low perfusion surrounding the AVM, emphasizing the risk of normal perfusion pressure breakthrough, is provided by cortical perfusion pressure, cortical cerebral blood flow (CBF), and stable xenon computerized tomography CBF measurements. The staged approach to giant AVM management is a proposed method to render AVM's that were previously considered inoperable or marginally operable into totally excisable lesions, while maintaining an acceptable level of morbidity and mortality.

Adolescent↗
PubMed1987

Scott Emergency Escape Breathing Device evaluation for use by aircraft cabin crew and passengers.

The Scott Emergency Escape Breathing Device (EEBD) was evaluated for use in Canadian Forces (CF) transport/passenger aircraft in providing smoke protection during emergencies and in preventing hypoxia during cabin decompression at high altitude. Five human subjects wearing the EEBD were subjected to decompression from 2,438 m (8,000 ft) to 9,753 m (32,000 ft) in approximately 15 s followed by a free fall to 7,010 m (23,000 ft) in a challenge gas atmosphere of 5,000 ppm of carbon monoxide (CO), where they performed moderate exercise (80 W output) on a bicycle ergometer. Very little in-leakage of CO was observed when the neck seal was maintained. Hood atmosphere was measured at 97% oxygen at 7,010 m, which resulted in an arterial oxygen saturation (SaO2) of 97%. Temperature in the hood rose to as high as 45.5 degrees C but the subjects were able to function normally. The EEBD is effective in providing noncockpit aircraft crew with smoke protection, adequate vision, and hypoxia prevention for at least 15 min in the event of a fire, smoke, or decompression emergencies at altitudes up to 7,010 m following a brief exposure to 9,753 m.

Accidents, Aviation↗
PubMed1986

Back injuries in industry: a retrospective study. I. Overview and cost analysis.

To evaluate the impact off back injury on industry, the authors conducted a retrospective analysis of injuries among hourly employees of a large industrial manufacturer in western Washington. The Boeing Company provided injury information on 31,200 employees for a 15-month period from July 1, 1979 to September 30, 1980. Of the 4,645 injuries reported, 900 were back injuries. Claims related to back injuries constituted 19% of all workers' compensation claims but were responsible for 41% of the total injury costs, or approximately $1,800,000. The 90 most expensive back injury claims (10% of all back injury claims) were responsible for 79% of the total back injury costs. The percentage of back injury claimants with claims having a total incurred cost exceeding $10,000 (6.5%) was significantly higher than the corresponding percentage of claimants (1.5%) with claims for other than back injuries (P = 0.000). A similar significant difference was found concerning the tendency of back injury claimants to have multiple claims compared with the non-back injury claimants. This retrospective study reaffirms the significant economic impact of back injuries on industry, and specifically high-cost back injuries. In addition, it provides insight into factors associated with back injury and points to positive measures that may be taken to reduce back pain and economic loss. Characteristics of the back injury and employee-related factors associated with back injury are presented in two subsequent articles.

Back Injuries↗
PubMed1986

Back injuries in industry: a retrospective study. II. Injury factors.

To evaluate the impact of back injury on industry, the authors conducted an extensive retrospective analysis of injuries among hourly employees of The Boeing Company, the largest industrial manufacturer in western Washington. The Boeing Company provided injury information on 31,200 employees for a 15-month period from July 1, 1979 to September 30, 1980. From this information, we analyzed 4,645 injury claims filed as of February 28, 1981 by 3,958 different employees. There were 900 back injuries in this group. Claims were categorized according to total incurred cost (TIC), made up of the medical costs and indemnity costs. High-cost claims were defined as those with a TIC greater than $10,000, and low-cost claims were those with a TIC less than $10,000. Among 857 claimants with 900 back injuries, lifting or material handling was much more commonly considered the cause of injury than accidents such as slips or falls. Accidents, however, had a much greater tendency to result in an expensive claim. The authors could not make reliable conclusions regarding injuries and 32 job skill classifications. The rate of injury did not vary according to day of the week or month, but a significantly higher rate of high-cost back injuries was noted on the day shift than on the evening or night shifts.

Absenteeism↗
PubMed1986

Back injuries in industry: a retrospective study. III. Employee-related factors.

To evaluate the impact of back injuries on industry, the authors conducted a retrospective analysis of injuries occurring among a group of 31,200 employees of The Boeing Company, a large industrial manufacturer in Western Washington. They analyzed 4,645 injury claims (including 900 back injuries) made by 3,958 different employees. Two previous articles give an overview of the study, provide a detailed analysis of the costs associated with these back injuries, and analyze the characteristics of the injury. This article focuses on employee-related factors associated with back injuries. Claims were categorized according to severity, as indicated by total incurred cost (TIC), the sum of the medical costs, and indemnity costs. High-cost claims were defined as those with a TIC greater than $10,000 and low-cost claims as those with a TIC less than $10,000. Employees younger than 25 years of age had a statistically significant increased risk of back injury, although their claims tended to be low-cost ones. This finding tends to discredit the premise that back problems are related to aging of the lumbar spine. While older employees had a lower injury rate, they did have a significantly increased risk of incurring high-cost back injury claims. The 31-40-year age group was the most susceptible to high-cost back injuries. Newer employees tended to have a significantly increased risk of back injury. The data show that women had fewer injuries than men but a statistically significant increased risk of becoming a high-cost injury claim.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Management of asymptomatic carotid atherosclerosis.

The detection, evaluation, and treatment of patients with asymptomatic carotid artery disease are controversial issues. In this review, these issues are addressed and the appropriate application of medical and surgical therapies is discussed. There seem to be two subgroups of asymptomatic patients with angiographically defined lesions (marked stenosis or large, deep, and compound ulcers) who have a significant risk of subsequent cerebral infarction. These patients should be considered for carotid endarterectomy at a surgical center with an established low incidence of perioperative complications.

Angiography↗
PubMed1986

A proposed grading system for arteriovenous malformations.

An important factor in making a recommendation for treatment of a patient with arteriovenous malformation (AVM) is to estimate the risk of surgery for that patient. A simple, broadly applicable grading system that is designed to predict the risk of morbidity and mortality attending the operative treatment of specific AVM's is proposed. The lesion is graded on the basis of size, pattern of venous drainage, and neurological eloquence of adjacent brain. All AVM's fall into one of six grades. Grade I malformations are small, superficial, and located in non-eloquent cortex; Grade V lesions are large, deep, and situated in neurologically critical areas; and Grade VI lesions are essentially inoperable AVM's. Retrospective application of this grading scheme to a series of surgically excised AVM's has demonstrated its correlation with the incidence of postoperative neurological complications. The application of a standardized grading scheme will enable a comparison of results between various clinical series and between different treatment techniques, and will assist in the process of management decision-making.

Cerebral Angiography↗
PubMed1985

Occipital artery to extradural vertebral artery bypass procedure. Case report.

A 17-year-old boy suffered blunt trauma to the posterior cervical spine and later developed vertebrobasilar transient ischemic attacks refractory to medical management. At angiography, a pseudoaneurysm of the distal left vertebral artery was found. By means of a posterior midline approach, an extradural occipital artery to vertebral artery anastomosis was performed and the affected vertebral artery was clipped distal to the pseudoaneurysm. The indications for this procedure, the operative approach, and the clinical outcome are described.

Adolescent↗
PubMed1982

Medial occipital arteriovenous malformations. Surgical treatment.

In a consecutive operative series of 115 intracranial arteriovenous malformations (AVM's), 16 occupied the medial occipital region. Typically, the patients with medial occipital AVM's presented with bleeding often accompanied by homonymous visual field deficit, or with migrainous headache. The malformations were supplied principally by branches of the posterior cerebral artery. Through an occipital craniotomy, a surgical approach along the junction of the falx and tentorium provided access to the arteries feeding the AVM and facilitated excision of the malformation. There were no deaths in the series. The incidence of visual field deficit after the operation varied, but in only five cases was the visual field worsened postoperatively. All patients who had a history of intractable headache were cured or improved after surgery. These lesions are favorably situated for surgical treatment.

Adult↗
PubMed1981

Development of pseudotumor cerebri after the removal of an adrenocorticotropic hormone-secreting pituitary adenoma: case report.

A patient with Cushing's disease developed intracranial hypertension 1 month after the removal of an adrenocorticotropic hormone-secreting pituitary adenoma. A computed tomographic scan demonstrated normal ventricles and no intracranial mass, establishing the diagnosis of pseudotumor cerebri. The elevated intracranial pressure was apparently consequent to an abrupt reduction in circulating corticosteroids. The development of pseudotumor cerebri after the correction of endogenous hypercortisolism has not been reported previously. This potential complication of the surgical treatment of Cushing's disease can be managed with prompt recognition and appropriate treatment of the syndrome.

Adenoma↗