Search PubMed⌕ Search

Biomedical subjects

F Robicsek

Publications and source records attributed to F Robicsek.

At least 37 records · Page 2Linked to original sources

Postoperative sterno-mediastinitis.

Postoperative sterno-mediastinitis is a life-threatening complication that occurs in about 0.75 to 1.4 per cent of all open heart operations. The result of treatment largely depends on timely diagnosis and appropriate surgical management. Risk factors for infection should be corrected preoperatively whenever possible. Among other preventive measures, meticulous asepsis, atraumatic surgical technique, preserving the blood supply and the mechanical integrity of the sternum, prevention of sternal instability, and correction of the same if it occurs are the most important. The management of sterno-mediastinitis should be tailored to the individual clinical features of the patients. Clearly cases with nonpurulent sternomediastinitis and no soft tissue or bone necrosis (type 1) may be treated with reopening, drainage, sternal stabilization, and primary closure. Virulent infections with tissue necrosis (type II) may be best handled with reopening, several days of open management, and debridement then secondary closure with viable tissue (usually muscle) flaps. Chronic, smoldering infections (type III) are usually managed with debridement and muscle-flap coverage.

Cardiac Surgical Procedures↗

Surgical treatment of pectus excavatum.

In conclusion, the following points are reemphasized: 1) The abnormal (either depressed or protruding) cartilages should always be resected. This resection, especially in pectus excavatum abnormalities, should not be overdone because the highest point that the chest wall and sternum can be elevated to with these types of operations is only the level of the most anterior rib and the thickness of the sternum itself. 2) Marlex mesh is an ideal material to support the sternum in its corrected position. It is strong and holds well until the chest wall solidifies. Also, it is resistant to infection and it may be left in place permanently. The application of different metallic splints, rods, and so on, as well as costal allografts, was found to be absolutely unnecessary. 3) Intercostal strips detached from the sternum may be left in place. Also, the surgeon should not waste time in performing a meticulous "classic" subperichondrial resection of the cartilages and ribs but should just leave enough perichondrium and periosteum behind to ensure the regeneration of the ribs. For the same reason, a segment of the most lateral portion of the cartilage should be left in continuity with the ribs. 4) It is strongly recommended that in excavatum anomalies, one of the pleural cavities should be deliberately opened and wide communication established between the pleural and the retrosternal space; the entire operative area should be drained for a day or two using an intracostal water-sealed catheter. This will make the use of any other subcutaneous or mediastinal drainage devices unnecessary and will ensure appropriate drainage of blood or serum. It is also recommended that the resection of the cartilages should be done on the left side first, where inadvertent entering of the pleura is less likely because of the backing of the pericardium. If it happens, drainage of the right hemithorax is not necessary. Carinatum anomalies are handled with subcutaneous drainage. 5) To confirm appropriate results, the chest should be carefully inspected after closure of the skin, and flaws, if they exist, should be corrected right then. Also, surgical repair of all pectus anomalies, especially excavatum deformities, should be supplemented in due time with an appropriate exercise program. Swimming and weight lifting are especially useful. 6) We found that the age limit imposed on small children by some authors is unnecessary, and as a matter of fact it is preferable to operate on children at an early age, around 2 years, because of commonly existing psychologic problems at a later age. The author advises restraint in operating on individuals past the teenage years unless the deformity is physiologically restricting. 7) The jury is still out regarding procedures using limited exposure and that do not use transverse sternotomy to correct the depressed or elevated sternal axis. 8) The usage of cosmetic procedures, or in other words, operations that do not correct the anomaly of the bony chest wall but use various implants as camouflage, should be restricted to cases of moderate excavatum anomalies in late teenage patients and to adults without cardiorespiratory symptoms.

Funnel Chest↗

Surgical treatment of pectus carinatum.

Pectus carinatum, just like its sister deformity pectus excavatum, is a condition with an undefined developmental mechanism and debated surgical techniques. Elongation of the costal cartilages and elongation and anterior displacement of the sternum characterize the different varieties of pectus carinatum. Repair of the anomaly involves positional correction as well as the shortening of the sternum and the maintenance of its corrected position by action of the rectus abdominis and pectoralis muscles.

Humans↗

Propagation of viral-size particles in lymph and blood after subcutaneous inoculation.

OBJECTIVE: We investigated the propagation of viral-size particles by lymph and blood after subcutaneous injection. METHODS: In the canine model, transport of [99mTc] sulfur colloid particles of different sizes was studied in different settings in venous blood and lymph for 45 minutes after inoculation. RESULTS: The mean arrival time of particles in the blood was 2.10+/-0.46 minutes and 8.87+/-1.72 minutes in the lymph. Lymph flow in the canine leg was 28.79 +/-2.09) microl/min and was increased by leg massage. The particle concentration was 1000 times higher in the lymph fluid than in blood. Particle flux values were comparable in blood and lymph. The accumulation of particles in blood initially rose faster than in lymph. Accumulation in lymph rises slower but continues longer and reaches higher values. Ninety percent of the inoculum remains at the injection site for at least 45 minutes. Particle size matters more in blood distribution. Leg massage enhances particle transport by lymph. CONCLUSIONS: After subcutaneous injection, viral-size particles initially arrive in the blood and later in the lymph. Accumulation in lymph and blood increases for a prolonged time after inoculation. Results suggest possibilities for limiting the spread of infectious matter by early local antiviral treatment.

Animals↗

Management of inflammatory aneurysm of the infrarenal aorta using retroperitoneal exposure, open aneurysmorrhaphy and descending aorta-to-femoral artery bypass.

The authors present a technique consisting of retroperitoneal exposure, but not dissection of the inflammatory aneurysm, anastomosis of a bypass graft through a short thoracotomy to the lowermost thoracic aorta, carrying it down retroperitoneally to both femoral arteries and under brief occlusion of the descending thoracic aorta, opening of the aneurysm and intra-aneurysmal occlusion of the inflow and outflow to the aneurysm. An illustrative case is presented.

Anastomosis, Surgical↗

Transport of viral-size particulate matter after intravenous versus intralymphatic entry.

OBJECTIVE: Investigation of the transport of viral-size particles after intravenous versus intralymphatic injection and the functional validity of lymphatico-venous communications. METHODS: In the canine model, [99mTc] sulfur colloid particles (100-200 nm) were injected into either the principal vein or into the main lymphatic channel exposed at the paw. Samples of blood and lymph were collected at the groin from the cannulated femoral vein and from a major lymphatic vessel. Parameters including particle arrival time, concentration, flux, and accumulation were determined for a 45-minute period using gamma counting. RESULTS: After intralymphatic injection, particles arrived in the venous blood in an average of 4 seconds. The mean arrival time of particles in the lymph after intravenous injection was 25.4 +/- 6.44 minutes. Intralymphatic injection increased lymph flow and enhanced particle transport. Concentration values in the venous blood after intralymphatic injection and in lymph after intravenous injection were comparable. Flux values depended primarily on flow conditions. Particle accumulation in the lymph after intravenous injection was delayed, but continued to increase throughout the experiment. CONCLUSIONS: There are functional lymphatico-venous communications at the very peripheral level under physiological conditions, which allow rapid transport of viral-size particulate matter between the two pathways and may contribute to the spread of viral infection.

Animals↗

Role of sinus wall compliance in aortic leaflet function.

Functional morphology of the normal aortic root was studied in vitro using 500 frames/s cinematography. Stiffening of the aortic wall by spraying its exterior with plastic adhesive led to compromised function of the leaflets, a phenomenon that may play a role in valve degeneration as it occurs in old-age fibrosis, atherosclerosis, or in connection with certain surgical procedures.

Aortic Valve↗

Commentary

Explore the source record for details and available documents.

Journal Article↗

Transport of colloidal particles in lymphatics and vasculature after subcutaneous injection.

This study was designed to determine the transport of subcutaneously injected viral-size colloid particles into the lymph and the vascular system in the hind leg of the dog. Transport of two colloid particles, with average size approximately 1 and 0.41 microm, respectively, and with and without leg rotation, was tested. Leg rotation serves to enhance the lymph flow rates. The right femoral vein, lymph vessel, and left femoral artery were cannulated while the animal was under anesthesia, and samples were collected at regular intervals after subcutaneous injection of the particles at the right knee level. The number of particles in the samples were counted under fluorescence microscopy by using a hemocytometer. With and without leg rotation, both particle sets were rapidly taken up into the venous blood and into the lymph fluid. The number of particles carried away from the injection site within the first 5 min was <5% of the injected pool. Particles were also seen in arterial blood samples; this suggests reflow and a prolonged residence time in the blood. These results show that particles the size of viruses are rapidly taken up into the lymphatics and blood vessels after subcutaneous deposition.

Animals↗

The influence of sizing on the dynamic function of the free-hand implanted porcine aortic homograft: an in vitro study.

BACKGROUND AND AIMS OF THE STUDY: The influence of sizing on the function of a porcine aortic valve after its implantation using the free-hand technique in the subcoronary position was investigated. METHODS: Dynamic function and leaflet configuration of the valve (n = 16) were first analyzed in its natural aortic root in a left heart simulator at 120/80 mmHg pressure and 4 l/min cardiac output. The valve was then implanted in the recipient porcine aortic root and re-studied. Three groups were investigated: group I (n = 4) comprised of 1-2 mm smaller donor aortic valve than the recipient; group II (n = 8) 3-4 mm smaller; and group III (n = 4) 5-7 mm smaller. Orifice area (OA), systolic and diastolic configurations of the leaflets, pattern and timing of leaflet opening and closure, commissural movement, pressure gradient and valvular regurgitation were analyzed. RESULTS: In the intact donor aortic root, average expansion of the aorta at the commissures, for a pressure change from 0 to 80 mmHg, was about 42%. This was reduced significantly in all assemblies. Group I showed a 34% reduction in OA, and excessive leaflet bending; there was no aortic insufficiency (AI) or pressure gradient across the valve. In group III there was a lesser reduction in OA and reduced leaflet bending, but two of four valves had AI. In group II, the reduction in OA was only 13%, there was less leaflet bending, and no AI. CONCLUSIONS: The donor valve 3-4 mm smaller than the recipient seems an optimal match. The current practice of using the same size donor as recipient may be responsible for excessive leaflet bending and may be implicated in early deterioration of the homograft.

Animals↗

Pressure traps in femoro-popliteal reversed vein grafts. Are valves culprits?

BACKGROUND: Stenosis is a major cause of vein graft failure in peripheral arterial surgery. Our goal is to determine whether vein valves play a role in this process by creating a "pressure trap". METHODS: Seventeen patients with femoro-popliteal reversed saphenous vein grafts were studied intraoperatively. Flow and pressure in the grafts were measured, while the graft outflow was gradually occluded and released for 2-4 seconds. In 3 patients the graft flow was reduced by compressing calf muscles. RESULTS: Patients heart rates were 54-84 BPM, blood pressures 170/80-110/55 mm Hg, and normal graft flow was 40-180 ml/min. In 12 patients with competent vein valves, at reduced flow (<30 m/min) the valves opened and closed in each cardiac cycle. At each closure the pressure was "trapped" distal to the valve producing diastolic hypertension. Also the flow was stagnant for a considerable portion of the cardiac cycle. Maximum diastolic pressure gradient across the valve ranged from 35 to 60 mm Hg and the level of pressure trapped was inversely proportional to the graft flow. CONCLUSIONS: In patients in whom reversed vein grafts with competent valves are placed in the femoro-popliteal positions a "pressure-trap" develops in the distal segment. This segmental hypertension combined with the flow stagnation could play an important role in the graft thickening and stenosis.

Anastomosis, Surgical↗