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Biomedical subjects

J G Vincent

Publications and source records attributed to J G Vincent.

46 records · Page 3Linked to original sources

Update on sternal osteosynthesis.

Interfragmental compression enables primary bone formation in the bone fracture line and results in better and faster contact bone healing. The Controlled Tension Osteosynthesis System is a simple and uniform sternal closure method that makes use of the principles of widely used modern osteosynthesis techniques. A review of tensile tests of currently available sternal closure methods has shown that the wire closure is the weak link in all procedures. An anchor plate has been developed as a more efficient means of wire closure. In contrast to the most commonly used wire twist closure, which has an optimum strength that is only 20% to 33% of the original wire tensile strength, the anchor plate closure retains up to 80% of the wire's tensile strength. Used in combination with a steel alloy wire with a metallurgically increased tensile strength, it results in a sevenfold to ninefold increase in effective fixation stability. A specially designed instrument, the Strainsqueezer, enables easy clinical application of the anchor plate under controlled, standard conditions. The system offers an optimal compression osteosynthesis fixation using a minimal amount of foreign body material (thin, prestressed wire). Its development was based on technical experience gained through 6 years of clinical practice involving 800 sternotomies.

Fracture Fixation, Internal↗

Reoperation for prosthetic heart valve replacement.

From 1974 to 1984, 847 heart valve replacement operations were performed with 1005 prosthetic valves. Thirty-nine (4.6%) were reoperations with 43 prosthetic valve replacements (PVR), on 38 patients. Thirty-three patients had received their initial valve replacement in our hospital and 5 elsewhere. Twenty additional cardiac procedures were required, concomitantly with the prosthesis replacement. Twenty-three patients underwent replacement of a mechanical prosthesis (61%) an average of 4.3 years after initial implantation and 15 patients a bioprosthesis (39%) after 2.8 years. Indications for PVR were endocarditis in 15 patients (39%), prosthesis failure in 13 (34%), periprosthetic leak in 7 (18%), thrombosis in 2 (5%), and a left ventricle subannular aneurysm in 1 (3%). Preoperatively 4 patients were in NYHA functional class II (11%), 15 in class III (39%) and 19 in class IV (50%). Six patients died early postoperatively (15.8%) Various risk factors were analyzed. The early mortality rate was 22% for mechanical prosthesis replacement and 7% for bioprosthesis; 11% for aortic position, 13% for mitral position and 50% to 100% for double valve replacement; 23% for non-elective and 6% for elective operations; 10% for patients with only an initial valve replacement and 43% with additional previous valve operations; 18% for active endocarditis, 15% for prosthesis failure, 14% for periprosthetic leak, 0% for thrombosis and 100% for subannular aneurysm; 0% for patients in class II, 7% in class III and 26% in class IV; 6% in patients with an aortic cross-clamp time less than 2 hours and 24% with more; 27% prior to 1981 and 9% during the last 4 years; and finally 50% in patients over the age of 60.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Management of postcardiotomy cardiogenic shock with a new pulsatile ventricular assist device. Initial clinical results.

The authors began ventricular assist pumping as treatment for postcardiotomy cardiogenic shock in November 1988 with a new automated pulsatile support system, the ABIOMED BVS 5000 Bi-Ventricular Support System. Five patients (0.6% of total cardiac surgery patients) have been placed on support, four after coronary artery bypass grafting, and one after bypass grafting and mitral valve repair. All patients were refractory to pharmacologic and intraaortic balloon pump therapy. Three patients had left ventricular support and two had biventricular support. Four patients were successfully weaned, and three are long-term survivors. Duration of support ranged from 39 to 118 hours (mean, 89.4 hours). Resternotomy was performed in four patients: twice for hemostasis, once for tamponade, and once for inadequate left ventricular drainage. Three patients, two nonsurvivors and one survivor, had perioperative myocardial infarctions. No device related thromboembolic complications, hemolysis, or infection were experienced. Follow-up at more than 1 year demonstrated that all patients are in NYHA Class 1. Ventricular assist pumping with the ABIOMED BVS 5000 Bi-Ventricular Support System is an effective treatment for postcardiotomy cardiogenic shock.

Coronary Artery Bypass↗

Unusual haemostasis for an unusual tumour. Catastrophic bleeding from a tactile neurofibroma affecting the thoracic vertebrae. Case report.

The symptomatology of a typical acute descending thoracic aorta dissection was imitated by profuse haemorrhage caused by a benign tumour composed almost exclusively of Wagner-Meissner like tactile corpuscles and fatty tissue. The tumour caused extensive destruction of the bodies of the fifth and sixth thoracic vertebrae at the level of the vertebro-costal articulation. Emergency cross clamping of the descending aorta and haemostasis of the bleeding from osteal defects by tamponade with bone polymethyl methacrylate appeared the only way to control the life threatening haemorrhage. It seems that an intrathoracic tactile neurofibroma with a similar case history has not been reported till now.

Aortic Dissection↗

A denaturated venous homograft as an alternative material for shunts and other reconstructions in congenital cardiac surgery.

A human venous homograft "Varivas R", in clinical use for 10 years for vascular access loops and femoropopliteal bypasses, has been used since December 1985 as a material for aortopulmonary shunts and other reconstructive procedures in congenital heart surgery. For this purpose vein segments 5 cm length, varying in diameter from 4 up to 10 mm by steps of 1 mm, were obtained. Our experience with Varivas is limited to 59 patients. Of 47 infants, 18 received a left, and 25 a right sided aortopulmonary shunt, 9 had bilateral aortopulmonary shunts, 2 right ventricle pulmonary conduits, 1 a pulmonary-pulmonary conduit, 3 interrupted aortic arch reconstructions and 4 a central aortopulmonary shunt, 1 with confluence reconstruction, 3 recidives of coarctation a patch repair. Among 11 adults 6 received coronary bypass and 6 others vascular reconstructions. In contrast to other artificial graft materials, the vein material offers easy manipulation similar to the daily routine of handling fresh vein material offers easy manipulation similar to the daily routine of handling fresh vein grafts in coronary surgery. The appropriate diameter sizes match better the infants anatomy, without the risk of kinking and/or anastomosis displacement. Peroperatively it was possible to confirm patency by electromagnetic flow measurement and the postoperative examinations were done by colour Doppler echocardiography. We had to reoperate upon 4 infants because of early thrombosis; on 1 infant for stenosis of the graft and on another 5 for late thrombosis. In an attempt to extend the indications for "inoperable" pulmonary hypoplasia/atresia we were not able to keep the shunt open in 4 infants.

Echocardiography, Doppler↗

Intraoperative fiberoptic angioscopy to evaluate the completeness of pulmonary embolectomy.

Intraoperative angioscopy was performed in three patients who underwent pulmonary embolectomy for massive pulmonary embolism. Angioscopy followed conventional techniques such as extracting the clot by a gallstone forceps, using a Fogarty catheter in the pulmonary tree or squeezing of the lungs. The rationale for angioscopy was to assess the result of these usual "blind" techniques. In two patients residual thrombus was detected and removed under direct visual control. Our initial experience suggests that intraoperative angioscopy appears to be useful in the detection of residual thrombus material, especially in the asanguinous, arrested heart. The small size of the angioscope allows easily access to the secondary, and up to the tertiary pulmonary branches. Clots can be visualized and extracted under direct visual control.

Adolescent↗