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Biomedical subjects

G Geremia

Publications and source records attributed to G Geremia.

12 recordsLinked to original sources
PubMed2000

Occlusion of experimentally created fusiform aneurysms with porous metallic stents.

BACKGROUND AND PURPOSE: Carotid fusiform aneurysms are most commonly treated with occlusion of the parent vessel. The purpose of our study was to assess the effectiveness of self-expanding, cobalt-alloy stents in the ablation of experimental fusiform aneurysms with preservation of the parent vessel in a carotid artery model. METHODS: Porous metallic stents were placed endovascularly along the lengths of experimentally created fusiform aneurysms in the carotid arteries of dogs; aneurysms were also created in the animals' opposite carotid arteries to serve as controls. RESULTS: Before stent placement, angiography of the carotid arteries showed large fusiform aneurysms along the lengths of the common carotid arteries and complex patterns of flow. Immediately after stent placement there was disruption of the usual flow patterns within the lumens of the fusiform aneurysms. The lumen between the wall of the aneurysm and stented carotid showed stasis of contrast material and blood. Near-complete ablation of all aneurysms was observed 8 weeks after stent placement. The stented carotid arteries remained widely patent; control aneurysms and carotid arteries were patent and unchanged. Histopathologic analysis revealed fibrotic reactive scar tissue filling the space between the stent wires and outer wall of the fusiform aneurysm. CONCLUSION: Changing blood flow dynamics within an aneurysm can promote thrombus formation. The stent promotes stasis and thrombus within the residual lumen between the stent wall and the outer wall of the aneurysm because its woven wire mesh interferes with usual blood flow patterns, which then promotes formation of thrombus and fibrosis within the residual aneurysmal lumen.

Aneurysm↗
PubMed2000

Percutaneous needle biopsy of the spine.

Technological advances in imaging and needle systems have made percutaneous needle biopsy of the spine safe and effective. Today, this procedure has largely replaced more invasive and costly open surgical procedures.

Back Pain↗
PubMed1999

Wada difference a day makes: interpretive cautions regarding same-day injections.

OBJECTIVE: To determine whether memory scores after second intracarotid amobarbital procedure (IAP) injections are affected by the time between the first and second injections. METHODS: Sixty-two patients received their second IAP injection on the day after the first injection. Forty-three other patients received the second injection on the same day as the first injection. Both groups underwent similar IAP protocols and memory assessments, except for the timing of the second injection. RESULTS: The second IAP memory scores in the two-day group were significantly higher (p < 0.05) than those in the one-day group. Timing of second injection was a significant correlate of second memory scores, but amobarbital dosage, first IAP memory score, and pre-IAP measures of memory and intelligence were not significant correlates. CONCLUSION: One-day and two-day IAP protocols do not result in similar memory scores after the second injection. Nineteen percent of a subset of patients in the one-day protocol were misclassified, in terms of IAP memory ratings, because of the deleterious effect of having both injections on the same day. It is recommended that correction scores be considered, for some patients who receive two IAP injections on one day, to approximate what the second IAP memory score would have been had the second injection occurred on a second day.

Adolescent↗
PubMed1997

Experimental arteriovenous fistulas: treatment with silicone-covered metallic stents.

PURPOSE: To determine the efficacy of silicone-covered metallic stents in the treatment of experimentally created carotid-jugular fistulas. METHODS: Carotid-jugular fistulas were surgically constructed in six mongrel dogs. Silicone-coated, self-expanding metallic stents were placed across the fistula holes within the carotid artery, and carotid angiography was performed before, immediately after, and 4 and 8 weeks after stent placement. Fistula specimens were resected 2 months after stent placement and analyzed by means of gross and light microscopy. RESULTS: Angiography revealed complete closure of all fistulas immediately after stent deployment. The fistulas remained closed and all carotid arteries remained patent. Marked stenosis within the carotid lumen was seen along the proximal and distal ends of the stents. Gross and micropathologic specimens of the carotid-jugular fistulas revealed fibrous connective tissue and collagen across the fistula holes. Proliferative fibrous connective tissue, collagen, and fibromyoblasts were located at either end of the stents. The wires of the stents indented the intraluminal surface of the carotid arteries. CONCLUSIONS: Silicone-covered stents were effective in closing all experimentally created carotid-jugular fistulas. With further refinements and variations in technique, covered stents may prove a viable alternative to current endovascular devices.

Animals↗
PubMed1995

Use of transcranial cerebral oximetry to monitor regional cerebral oxygen saturation during neuroendovascular procedures.

Using transcranial cerebral oximetry, we monitored 30 patients who underwent cerebral angiography by the femoral route. Transcranial cerebral oximetry is a noninvasive technique of regional cerebral oxygen saturation measurement that uses near-infrared spectroscopy to differentiate oxyhemoglobin from reduced hemoglobin. Needle puncture, catheterization, and contrast media injection produced no significant peak changes in saturation from baseline. Acute and persistent decreases in oxygen saturation were associated with vascular complications and were detected before development of clinical symptoms. Greater changes in saturation were observed during several neuroendovascular procedures, indicating the development of complications, signaling a need to stop further endovascular manipulation.

Brain↗
PubMed1994

Embolization of experimentally created aneurysms with intravascular stent devices.

PURPOSE: To assess the effectiveness of self-expanding, cobalt-alloy stents in the treatment of aneurysms in a canine model and to observe the pattern of blood flow and formation of fibrotic scar tissue. METHODS: Porous metallic stents were endovascularly placed across the necks of experimentally created side aneurysms in the carotid arteries of three dogs; aneurysms were also created in the opposite carotid arteries in these animals to serve as controls. RESULTS: Before stent placement, angiography of the carotid arteries demonstrated whirl-like, vortex flow of blood within the lumens of the aneurysms. Inflow was seen along the distal aneurysm wall; outflow was demonstrated along the proximal wall; slower vortex flow was present in the central lumen. Immediately after stent placement there was disruption of the usual vortex flow with stasis of contrast media and blood within the lumen. Inflow and outflow patterns were no longer seen. Complete ablation of these aneurysms was evident at follow-up angiographic studies--1 week, 1 month, and 2 months after stent placement. The stented carotid arteries remained widely patent; control aneurysms and carotid arteries were patent and unchanged. Histopathologic analysis revealed fibrotic reactive scar tissue completely filling the stented aneurysm pouches. CONCLUSION: Treatment of selected intracranial aneurysms via an endovascular approach has merit and could supplant more invasive, risky, and costly surgical procedures in some cases.

Animals↗
PubMed1989

Intrasellar balloon inflation for treatment of symptomatic empty sella syndrome.

Intrasellar extradural placement of a detachable vascular balloon via a transsphenoidal approach was performed successfully in a patient with primary empty sella syndrome, relieving headache and visual field defect. This technique offers an alternative approach to other methods of treating symptomatic empty sella syndrome that require packing of the sella with fat, muscle, cartilage, or bone.

Adult↗
PubMed1984

An unusual case of rounded atelectasis.

An unusual case of rounded atelectasis (RA) is described. This entity is likely to develop as a consequence of asbestos-induced pleural disease. The sine qua non of RA is a curvilinear tail extending from the inferior medial surface of a peripheral mass. Recognition of this "comet tail" prevents the necessity for surgery.

Asbestos↗
PubMedDate not supplied

Experimental arteriovenous fistulas: treatment with porous metallic stents.

PURPOSE: To determine the efficacy of porous metallic stents in the treatment of experimentally created carotid-jugular fistulas. METHODS: Carotid-jugular fistulas were constructed surgically in five mongrel dogs. Porous metallic stents were placed endovascularly across the fistula holes within the carotid artery; carotid angiography was performed before, immediately after, and 1 and 2 months after stent placement. The fistula specimens were resected 2 months after stent placement; gross and light microscopic analyses were performed. RESULTS: Angiography revealed complete closure of three of the five fistulas 1 month after stent placement; two of the five fistulas remained patent but demonstrated diminished flow rate. All carotid arteries were widely patent throughout the study. Gross pathology of the carotid-jugular specimens revealed fibrous connective tissue and collagen within the fistula hole. A thin layer of endothelium covered the stent wires and the fibrous connective tissue overlying the fistula hole. CONCLUSIONS: The stents were effective in closing three of the five fistulas and reducing flow through the fistulas in the remaining animals. With further refinements and variations in technique, porous metallic stents may prove a viable alternative to current endovascular devices for treatment of certain arteriovenous fistulas.

Angiography↗