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Biomedical subjects

C E Seibert

Publications and source records attributed to C E Seibert.

18 recordsLinked to original sources
PubMed1997

Ethanol endovascular management of brain arteriovenous malformations: initial results.

OBJECTIVE: The goal was to determine the safety and efficacy of absolute ethyl alcohol treatment in the management of intra-axial brain arteriovenous malformations (AVMs). METHODS: Seventeen patients (eight female and nine male patients; mean age, 41 yr) underwent ethanol endovascular therapy for treatment of their brain AVMs. Superselective amytal testing preceded all procedures. Neuroleptic intravenous anesthesia was used for 16 patients, and general anesthesia was used for 1 patient. Follow-up monitoring consisted of clinical evaluations, magnetic resonance imaging, and arteriography. RESULTS: In follow-up evaluations (mean follow-up period, 13 mo) after embolization of brain AVMs, neither vascular recanalization nor the neovascular recruitment phenomenon was observed in any patient. Progressive AVM thrombosis at arteriographic follow-up evaluation was a constant feature. Seven patients were cured of their AVMs with ethanol endovascular therapy alone. Three patients were cured of their lesions with ethanol embolization plus surgical resection. One patient was cured of his lesion with ethanol embolization and radiation therapy of the residual nidus. Three patients underwent only partial therapy, with significant improvement in symptoms. Three patients are currently undergoing ethanol endovascular therapy. Complications occurred with 8 of 17 patients, most of which were transient. Two patients died because of late subarachnoid hemorrhages, one patient 4 months and one patient 14 months after partial therapy. CONCLUSION: Progressive and permanent AVM occlusion is a common finding in arteriographic follow-up evaluations. In no patients did arterial recanalization or the neovascular recruitment phenomenon occur. Our initial results indicate that ethanol has a permanence that is seldom encountered with other embolic agents. With aggressive decadron therapy, the complications related to swelling in the brain are largely reversible.

Adult↗
PubMed1996

CT imaging of radiopaque shunt catheter after endolymphatic duct surgery.

Until now, shunt catheters used in endolymphatic sac (ELS) and duct surgery have not been visible at computed tomography (CT) imaging. This report summarizes findings at postoperative CT in 50 patients who underwent endolymphatic system decompressive surgery with a new opaque shunt catheter placed at or into the endolymphatic duct (ELD). The catheter was visible in all 50 cases, and the best projection for visualization was the semicoronal view. The postoperative visualization of the opaque shunt catheter allows determination of the exact placement of the catheter (a) in the bony vestibular aqueduct (within the membranous ELD); (b) at the external aperture of the bony vestibular aqueduct (within or at the membranous ELD at its junction with the ELS); or (c) outside the bony vestibular aqueduct system or aperture but presumably within the membranous ELS. These objective findings may be used as a marker to help predict outcomes from this type of nondestructive inner ear surgery, as well as to determine exactly where the surgeon placed the shunt-tube catheter tip.

Endolymphatic Duct↗
PubMed1992

Pedicle diameter determined by computed tomography. Its relevance to pedicle screw fixation in the lumbar spine.

Intraoperative technical complications of pedicle screw fixation include screw cutout or maldirection and pedicle fracture. The aims of this study were 1) to use computed tomography to determine the average pedicle diameter; and 2) to compare these measurements with the outer diameter measurements of commonly used pedicle screws. The pedicle diameters of L2, L3, L4, L5, and S1 were measured in 154 adult patients (81 men, 73 women) who had low-back pain. The distance across the isthmus of the pedicle was measured with the distance mode on the axial computed tomographic image in the bone window setting. The lateral computed tomographic scout view was used to select the axial section through the midportion of the pedicle. To standardize data retrieval, the lower four motion segments were denoted as L2-S1, even when there were more or fewer than five lumbar vertebrae. The pedicle diameter at each level was measured and averaged for all patients and for men and women separately. The percentage of pedicles that measured less than 7 mm was determined at each level. The average pedicle diameters were 8.13 mm for L2, 8.7 mm for L3, 10.88 mm for L4, 14.54 mm for L5, and 18.37 mm for S1. Twenty percent of the L2 pedicle diameters, 15.6% of L3, and 1.9% of L4 were less than 7 mm; none of the L5 or S1 pedicles measured less than 7 mm. The outer diameters of the most commonly used pedicle screws range from 5 mm to 7 mm. Screw pitch, tooth profile, outer diameter, and depth of penetration affect implant strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Ethanol embolization of vascular malformations.

Absolute ethanol was used to treat 20 patients with symptomatic vascular malformations (SVMs) (ie, venous malformations, arteriovenous malformations, and congenital and posttraumatic arteriovenous fistulas) in whom previous surgery or standard embolotherapy had failed or who were not candidates for surgery. All large complex lesions required multiple embolizations as staged procedures. Immediate thrombosis was achieved in all patients; complications (13% of cases) were generally minor and were treated conservatively. Follow-up studies, performed in 19 of 20 patients, showed persistent occlusion of the SVM in all cases. Ethanol embolization of SVMs, performed according to strict techniques, has proved efficacious in SVM management and is emerging as a definitive form of therapy.

Adolescent↗
PubMed1990

Neuroradiology of vestibular pathways.

Comprehensive efficacious neuroimaging of the vestibular pathways requires cooperation and coordinated efforts between the otologist and the neuroradiologist to avoid duplication of expensive and sometimes invasive study. For peripheral lesions, for example, those of the labyrinthine organ, thin-section CT is optimum as a first examination. For retrolabyrinthine lesions along nerve tracts or in the central pathway, MRI is preferred. When bone erosion occurs, CT can also be helpful in evaluation of the base of the skull to detect and define the extent of these lesions, for example, cholesterol granuloma and glomus tumor.

Dizziness↗
PubMed1988

Sneddon's disease presenting with visual loss and dementia.

A 51-year-old woman with Sneddon's disease presented with transient right hemifield loss of vision and transient right-sided weakness. Over the preceding decade she had experienced a slow decline in mental function. She also had hypertension, migraine, and a mixed seizure disorder. She had skin changes typical for generalized livedo reticularis but she did not have Raynaud's phenomenon or winter ulcerations. Her disease was not understood until the stroke-related symptoms were associated with the skin abnormalities. We review the neuro-ophthalmic manifestations of Sneddon's disease and add data from our case to the growing body of fact that suggests that Sneddon's disease may be an immunologically mediated vasculopathy.

Cerebrovascular Disorders↗
PubMed1986

Radiographic imaging of the cochlear implant candidate: preliminary results.

Preoperative radiographic imaging of the temporal bone is well accepted in otology for both the diagnosis of disease and the delineation of anatomic structure for surgical planning. Until recently radiographic techniques have unfortunately failed to demonstrate fibrous or bony obstruction of the basal turn of the cochlea, which may cause difficulties during cochlear implantation. Intraoperative findings have been correlated with preoperative imaging in a consecutive group of six cochlear implant recipients and a series of consistent radiographic signs that may indicate the presence of obstruction of the scala tympani have been identified. A classification system has been developed. Based on thin-section high-resolution computerized tomography (HRCT), the system has been used preoperatively on six cochlear implant recipients. In addition, a systematic evaluation of the temporal bone has been developed for precochlear implant evaluation. This includes the thickness of the parietal bone for seating of the receiving device, the degree of pneumatization of the mastoid, the measurement of the size of the facial recess, the description of the size and orientation of the round window niche, and the patency of the basal turn of the cochlea.

Adult↗
PubMed1981

Accurate CT measurement of the spinal cord using metrizamide: physical factors.

Computed tomography (CT) using metrizamide is a valuable tool in the neuroradiologic evaluation of the spinal cord, but CT must be used with care when measuring object size because size may vary with different window center (level) settings. A simple method to determine appropriate window center (level) settings during CT object measurement is described. A polystyrene core with a Teflon outer cylinder designed to simulate the spinal column, spinal cord, and subarachnoid space was scanned with varying concentrations of metrizamide with an EMI 1010 unit. Computer printouts of the CT pixel matrix were analyzed and a constant relationship of the phantom cord true size to the CT numbers of the metrizamide concentration and the phantom spinal cord was found. Window center (level) selection greatly influences measurement of cord size, whereas window width dose not. The appropriate window center (level) selection is the mean between the metrizamide CT attenuation number and the cord CT attenuation number.

Evaluation Studies as Topic↗
PubMed1981

Progressive posttraumatic cystic myelopathy: neuroradiologic evaluation.

The neuroradiologic evaluation and findings in 25 symptomatic patients with surgically proven progressive posttraumatic cystic myelopathy are reviewed. To follow patients with spinal cord injury, neuroradiologic algorithms were developed to confirm and define cystic myelopathy. The algorithm used in the early and mid 1970s relied on the myelographic demonstration of a large cord for suspicion of a cyst. Review of this material found that in progressively symptomatic patients 14 of 25 proven cysts were in large cords. A more recent algorithm used computed tomographic metrizamide myelography. In nine of 11 patients studied in this fashion, the cyst filled with contrast material 2--4 hr after injection, yet it did not communicate with the subarachnoid space at subsequent surgery. The origin of the cyst fluid and mechanism of cyst demonstration with metrizamide may be associated with transneural migration of fluid. This condition must be clinically suspected and radiologically confirmed for surgical treatment (cyst-shunt procedure) if neurologic preservation of function is to be maintained.

Cysts↗
PubMedDate not supplied

Duplex sonography in the evaluation of carotid artery disease.

High-resolution duplex sonography was compared with biplane magnified carotid angiography in a prospective evaluation of 161 carotid arteries in 86 patients. The duplex scanner combined real-time B-mode imaging (7.5 MHz) with simultaneous range-gated pulsed Doppler frequency analysis (3 MHz). The degree of stenosis was usually determined by the true and residual lumen of the carotid artery at the atherosclerotic plaque on the transverse image. The Doppler frequency signals were automatically converted to velocity data by a minicomputer. The accuracy of the duplex system in detecting and assessing stenoses graded in 20% increments is demonstrated according to specificity, sensitivity, and positive and negative predictive value by both cumulative and subgroup analyses. A 93.7% sensitivity was shown for minimal (0-20%) stenosis and 100% sensitivity for severe (greater than 60%) stenosis. An apparent limitation of duplex sonography is the differentiation of a high-grade stenosis from occlusion (sensitivity, 82.6%; positive predictive value, 90.4%).

Carotid Arteries↗