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Biomedical subjects

S Bowald

Publications and source records attributed to S Bowald.

53 records · Page 3Linked to original sources
PubMed1982

Regeneration of peripheral nerve through a polyglactin tube.

Polyglactin 910, a resorbable synthetic material, was used as a mesh-tube to bridge defects (7 to 9 mm in length) in a sectioned rabbit tibial nerve. After absorption of the mesh a new nerve sheath was formed which enclosed numerous minute fascicles of regenerating axons. The polyglactin tube influenced the direction taken by the regenerating axons and guided them into the distal segment. The tube also reduced the formation of neuromas and the growth of scar tissue from surrounding structures.

Animals↗
PubMed1982

Peroperative assessment in arterial surgery--flow determination or angiography?

Complete data from flow measurement and intraoperative angiography were obtained in 70 femoro-popliteal vein by pass procedures. The results were compared in respect to their predictability of early outcome after arterial reconstruction. A correct prediction was given in 65 of 70 cases (92 per cent) by angiography. The corresponding figure for flowmeter determination was 52 of 70 (74 per cent). Angiography was found to be preferable to flow determination especially when low flow values were registered.

Aged↗
PubMed1982

The posterior approach for subfascial ligation of perforating veins.

A posterior midline incision was used for subfascial ligation of incompetent medial and lateral perforating veins in 57 limbs. The indications for surgery were recurrent ulceration in 41 limbs and severe skin changes in 16 limbs. At follow-up two years or more after surgery 48 limbs remained free from ulceration. Wound infection (7%) and necrosis (12%) healed with conservative treatment. In our experience the posterior approach is a good alternative to other methods for ligation of incompetent perforating veins in patients with advanced skin changes, including active ulceration.

Female↗
PubMed1981

Repair of cardiac defects with absorbable material.

Partial resection of the right atrium was performed in 5 young pigs. The defect was covered with a patch graft of absorbable material (polyglactin 910). Ten weeks postoperatively the mesh was completely replaced by a newly formed tissue with a smooth inner surface. Light microscopy showed regeneration of fibro-elastic tissue and the luminal surface was covered with endothelial-like cells indistinguishable from normal endocardium.

Animals↗
PubMed1980

The influence of heparin on haemodynamics and blood gases during abdominal aortic surgery.

Central haemodynamics and blood gases were measured in 26 patients undergoing elective aortic surgery for atherosclerotic or aneurysmal disease. Recordings were made at seven defined time points, starting before anaesthesia and ending 30 min after declamping of the aorta. The patients were randomly divided into two groups, one receiving heparin at an early stage and the other at a late stage of the operative procedure. A declamping shock phenomenon could be prevented by thorough blood and fluid replacement. After removal of the aortic clamp the cardiac output increased, except in a few patients who were considered preoperatively to be poor risks. A significant decrease in arterial oxygen tension and increase in pulmonary artery and pulmonary capillary wedge pressures occurred in patients receiving heparin at a later stage. The effect of heparin points to possible intravascular coagulation and pulmonary microembolism during the operation.

Aged↗
PubMed1980

Effects of aortic occlusion in heparinized and non-heparinized pigs.

The aorta and common iliac arteries were clamped for 2 hours in 27 pigs under general anaesthesia. Ten pigs were heparinized and the other 17 did not receive heparin. A further 5 pigs were used as sham-operated non-heparinized controls. Blood gases and also mean arterial, pulmonary arterial, pulmonary capillary wedge and left atrial pressures were recorded before, during, and after clamping. In the non-heparinized pigs there was a significant increase in pulmonary capillary wedge pressure during and after clamping of the aorta, slight variations in the left atrial pressure (measured in 5 non-heparinized pigs) and a decrease in PaO2, which was especially pronounced after declamping of the aorta. No such changes occurred in heparinized or control animals. The discrepant results in heparinized and non-heparinized animals indicate a mechanism influenced by heparin. Clamping and declamping of the aorta obviously accelerated the changes in the non-heparinized animals. It is suggested that these changes are caused by pulmonary embolism induced by the clamping and declamping of the aorta. Alterations in the pulmonary circulation indicated that the mean pulmonary capillary wedge pressure is not a reliable indicator of left ventricular filling pressure during aortic surgery.

Animals↗
PubMed1980

Pulmonary microembolism during and after aortic cross-clamping in heparinized and non-heparinized pigs.

The occurrence of pulmonary microembolism after aortic clamping and declamping was investigated in 21 young pigs. The prophylactive effect of heparin was also examined. Eight animals were heparinized, while 13 did not receive heparin. In 15 pigs the plasma concentration of fibrinogen was determined before, during and after clamping of the aorta. External detection of 51Cr-labelled platelets and 125I-labelled fibrinogen was performed. Lung tissue from these animals was homogenized and analysed for radioactivity. Specimens were taken from the lungs of all animals for morphological investigation. A significant decrease in plasma fibrinogen concentration was noted during the aortic clamping in non-heparinized animals. Morphological studies of lung tissue revealed numerous fibrin/platelet thrombi, leukocyte and platelet aggregates, atelectases and bleedings. In homogenized lung tissue, areas with elevated radioactivity were found, indicating fibrin/platelet entrapment. No such changes were seen in pigs pretreated with heparin. It was found that pulmonary microembolism occurs frequently after aortic clamping if heparin is not given at an early stage of the procedure.

Animals↗
PubMed1980

Absorbable material in vascular prostheses: a new device.

Seven to twenty cm long bypass grafts were inserted between the upper and lower part of the descending aorts of 20 young pids with end-to-side technique. The aorta between the anastomoses was closed by a ligature. As graft materials were used circular polyglactin 910 (Vicryl) mesh tubes (group I), external PTFE graft (Impra) and internal polyglactin mesh tube (group II), PTFE graft (group III) and external dacron mesh tube and internal polyglactin mesh tube (group IV). The biological process taking place in the grafted area was studied by light microscopy. The following observations were made: (1) The regenerative capacity of the pig aortic tissue permits 7 to 15 cm long polyglactin mesh grafts to be replaced by a new endothelialized vessel wall imitation. (2) When resorbable and non-resorbable materials were combined to form a composite graft (groups II and IV) the result proved to be a prosthesis with an internal covering of endothelialized arterial tissue.

Animals↗
PubMed1979

Arterial regeneration following polyglactin 910 suture mesh grafting.

A suture mesh of polyglactin 910 [Vicryl (polyglactin 910) suture mesh] was placed as a patch graft into the thoracic aorta of 23 growing pigs. In three other pigs the mesh was grafted in the form of a tube to replace a short aortic defect. The biological processes taking place in the grafted area were studied by morphological methods. The following observations were made: (1) Hemostasis readily occurred by fibrin, platelet, and erythrocyte embedding of the mesh. (2) Early outgrowth of smooth muscle cells around the mesh took place from the normal aortic media and from a newly formed subintimal smooth muscle layer. (3) The newly formed arterial tissue was completely endothelialized within 20 days. (4) The polyglactin mesh had disappeared almost completely at 40 days, but the new wall seemed to retain sufficient strength throughout the observation time. (5) Only irregular deposition of elastic fibrils occurred, but in other respects the new tissue structurally resembled normal arterial tissue.

Animals↗
PubMed1978

Intraoperative angiography in arterial surgery.

Intraoperative angiography was performed in 136 cases of surgical reconstruction of the aorta, iliac, femoral and carotid arteries. In 39 cases pathological angiograms were found at operation, some of them quite unsupected. The most common pathological finding was non-occluding thrombosis, but intimal lesions caused by vessel clamps and incomplete endarterectomies were not uncommon. Immediate surgical reexploration and revision resulted in a high frequency of open reconstructions at follow-up, which was performed 1--24 months postoperatively. On the other hand, nonrevised reconstructions with pathological angiograms usually failed in the early postoperative period. In cases with normal intraoperative angiograms the result at follow-up was excellent. In addition to electromagnetic flow determination, intraoperative angiography is a most valuable adjunct in the assessment of vascular surgery during operation and should be used more frequently. All pathological findings in the angiograms must be seriously considered and lead to reexploration and revision.

Angiography↗
PubMedDate not supplied

Surgical treatment of pararenal abdominal aortic aneurysms.

Thirty patients with juxtarenal infrarenal and 16 patients with suprarenal abdominal aortic aneurysms underwent elective (58%) or urgent (42%) repair. Twenty-three patients were hypertensive and 20 had impaired renal function preoperatively. Nineteen patients required combined aortic and renal artery reconstruction, in which reimplantation was the most common technique used. The perioperative mortality rate was 7.4% in the elective group and 36.8% in the urgent group. Rupture of the aneurysm and a preoperative high serum creatinine level were risk factors correlating to early mortality. Among survivors, 61% showed a rise in serum creatinine in the early postoperative period. In all but one the transient renal insufficiency was resolved within one month. Of the hypertensive patients 64% were cured or under control with medication following combined reconstruction. These results demonstrate that surgical repair of pararenal abdominal aortic aneurysms can be performed with an acceptable mortality and morbidity.

Aged↗
PubMedDate not supplied

Renal complications to left renal vein ligation in abdominal aortic surgery.

Postoperative renal complications have been investigated in 31 patients subjected to left renal vein ligation during abdominal aortic surgery (11 ruptured and 18 non-ruptured aneurysms, 2 occlusive diseases). A marked increase in s-creatinine values was found in all patients after left renal vein ligation. The increase was significantly longer (p less than 0.01) and higher (p less than 0.005) as compared with control patients subjected to abdominal aortic surgery without ligation of the left renal vein. A sustained increase in postoperative s-creatinine values was found in 6 patients, one of whom had a total loss of left kidney function. Left-sided nephrectomy was necessary in 2 patients to control bleeding from the kidney. Acute haemorrhagic infarction and subinfarction of the left kidney were seen in 2 patients. A restricted application of left renal vein ligation during abdominal aortic surgery is recommended.

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