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Biomedical subjects

L T Ostrup

Publications and source records attributed to L T Ostrup.

At least 19 recordsLinked to original sources
PubMed1992

Long term evaluation of the unilink anastomotic system. A study with light and scanning electron microscopy.

The long term effects of the Unilink mechanical microvascular anastomosis in terms of anastomotic patency and histological changes in the vessel wall were evaluated in 10 rabbits. Both carotid arteries and facial veins were divided and reanastomosed with the Unilink device. At death two years later all 40 anastomoses were fully patent, with histological changes similar to those described previously after 16 weeks, that is, normal endothelial lining, but almost total atrophy of the media at the anastomotic site. The thinning of the vessel wall at the anastomosis caused neither occlusions nor aneurysms during the observation period.

Anastomosis, Surgical↗
PubMed1989

The UNILINK system for mechanical microvascular anastomosis in hand surgery.

A new mechanical anastomotic device--the UNILINK system--for small vessels, designed for work under the operating microscope was used in four patients for microvascular, hand surgical operations. All procedures were successful with regard to tissue survival and wound healing. Basal skin temperature and systolic blood pressure distal to the mechanical anastomoses were normal 12 to 26 months after the operation. Doppler investigation also confirmed that all mechanical anastomoses were patent. At the time of this report, 32 to 45 months after the operations, no adverse effects of the method have been found. The device offers increased safety and speed in microvascular operations.

Adolescent↗
PubMed1989

Microvenous end-to-side anastomosis: an experimental study comparing the Unilink system and sutures.

A method for mechanical microvascular end-to-side anastomosis is presented and compared to conventional suture technique. Twenty rabbits had their facial veins divided from the jugular veins and reanastomosed end-to-side to the jugular veins, 2 cm cranially to the original bifurcation. The anastomoses were performed on one side of the neck with the Unilink system and on the other side with sutures. At sacrifice at two weeks (10 animals) and at 16 weeks (10 animals), all anastomoses were tested for patency and histologically evaluated. All 40 anastomoses were fully patent. The time required for completion of a mechanical anastomosis was on the average one-fourth the time required for suture anastomosis. No thrombus formation was noted in any of the specimens, but a slight narrowing because of intimal hyperplasia was noted in the recipient vessels in two mechanical anastomoses. It was demonstrated that mechanical anastomoses of small veins end-to-side can be performed in a rapid and safe manner with the Unilink system.

Anastomosis, Surgical↗
PubMed1989

Arterial end-to-side anastomosis with the UNILINK system.

A new technique for mechanical end-to-side anastomoses using the UNILINK anastomotic system is presented. The technique, based on the concept of vessel wall eversion over paired ring pins, is described as is a new device for vessel expansion. To evaluate the technique of end-to-side anastomosis, we detached the left renal artery in 18 rabbits and then reanastomosed them end-to-side to the aorta using the UNILINK anastomotic system. Renal blood flow was evaluated before and after anastomoses with a laser Doppler flowmeter. Animals were separated into three groups of 6 and were killed at 24 hours, 2 weeks, and 16 weeks, respectively. To evaluate the acute effects of vessel expansion, 7 additional rabbits underwent expansion of the aorta without subsequent anastomosis. All vessels were evaluated with light and scanning electron microscopy. A patency rate of 100% was achieved in the 18 animals; histological changes at the anastomotic site were comparable to those described previously for this mechanical anastomotic system. The animal model demonstrates that it is both technically possible and efficacious to perform end-to-side anastomoses of arteries with the UNILINK anastomotic system.

Anastomosis, Surgical↗
PubMed1989

Microvascular anastomosis of interpositional vein grafts with the UNILINK system. A comparative experimental study.

Vein segments from the posterior facial vein of the rabbit were surgically isolated and re-anastomosed, either by manual suture technique or by the use of a new mechanical anastomotic device, the UNILINK apparatus. The purpose of the study was to compare anastomotic patency and time required for an orthotopic vein grafting procedure, when the two techniques were used. In the grafts anastomosed with the UNILINK technique, both clinical and histological evaluation showed 100% patency, while 20% of the sutured grafts showed impaired flow as a result of occlusive thrombosis. When the mechanical device was used, the full procedure was completed within one third of the time, as compared to suture anastomoses.

Anastomosis, Surgical↗
PubMed1987

Mechanical anastomosis of small arteries and veins with the unilink apparatus: a histologic and scanning electron microscopic study.

A new method for mechanical anastomosis of small vessels--the Unilink device--has been tested in 23 rabbits. A total of 81 arterial and venous anastomoses were performed. One of the arterial anastomoses were thrombotized, while the remaining 80 anastomoses were fully patent at 2 or 16 weeks. The repair process at the anastomotic site was very rapid both in arteries and veins. The endothelialization was complete at 2 weeks, but a marked atrophy of the media was noted in the arterial anastomoses. The same phenomenon was observed in the venous anastomosis, but to a much lesser degree. Thrombus formation was extremely rare, and the atrophy of the media did not seem to affect the patency rate. The experiment has confirmed that the Unilink method provides a very safe, fast, and simple way to perform microvascular anastomoses.

Animals↗
PubMed1986

The UNILINK instrument system for fast and safe microvascular anastomosis.

A new instrument system for fast and safe mechanical microvascular anastomosis is presented. It can be used for both end-to-end and end-to-side anastomosis of small arteries and veins and has the potential for use in other small tubular structures. With moderate training, the surgeon can perform the full microvascular anastomosis within 2 to 3 minutes. The device has proved successful in animal studies and in the clinic, with overall patency rates of about 98% in both arteries and veins.

Arteriovenous Shunt, Surgical↗
PubMed1986

Reconstructive microsurgery--a review.

We present some important current applications of reconstructive microsurgery. This field is expanding rapidly and the techniques are finding application in many branches of surgery. There is a pressing need for educational programs and training in microsurgery, as well as for continued research. Many of the procedures reviewed here have already been shown to substantially reduce costs, shorten hospitalization, and lessen patient disability; and as a result, several conventional procedures have been out-dated. We have stressed the concept that this is team surgery. To cover the needs of replantation and emergency free flaps around the clock, several microsurgeons must work together in established centers, and the team must possess expertise from all the involved surgical specialities. This may imply revision of many organizational aspects of patient care. Replantation centers would provide the necessary educational bases and give an impetus to the development of microsurgery.

Bone Transplantation↗
PubMed1985

Molded vascularized osteoneogenesis: a preliminary study in rabbits.

The clinical application of free vascularized bone grafting techniques in reconstructive surgery has limitations with respect to available donor sites and configuration of the graft. In this study, we were able to produce a vascularized bone graft with a predetermined size and shape by the use of titanium chambers implanted into the groins of rabbits. Forty adult New Zealand white rabbits were included in this study. In all animals, bone fragments were harvested from the iliac crests and placed within a titanium chamber. The chamber was positioned in the groin with the saphenous vessels passing through the chamber longitudinally in contact with the bony fragments. In half the animals, a segment of periosteum was harvested from the tibia and sutured around the vessels with the cambium layer facing the bone fragments. Sacrifices were performed at 4, 8, 12, and 16 weeks to examine the chamber contents. At all time periods, the contents completely filled the chamber, and the saphenous vessels remained patent. Histologic evaluation showed remodeling of the bone fragments as early as 4 weeks concomitant with a sprouting vascular network demonstrable with microangiography. Fluorochrome bone labels documented new bone formation within the chamber. These changes were progressive to week 12, but the 16-week specimens appeared to be undergoing resorption.

Angiography↗
PubMed1982

The importance of a maintained medullary blood supply for the survival of revascularized free bone grafts. Preliminary studies.

The importance of an intact medullary blood supply for bone cell survival in free microvascular bone transfers was investigated in 8 beagle dogs. Through a total osteotomy and incision of the surrounding soft tissues, the posterior part of the ninth rib was completely isolated on the intercostal artery and vein. In four of the dogs medullary blood supply to this rib segment was blocked by a semitotal osteotomy near the proximal end of the rib. At sacrifice (one day and 1, 2 and 4 weeks after the operation) bone survival in the isolated rib segment was evaluated by fluorochrome bone labeling, histology and microangiography. The results suggest that the bone segment can survive on the periosteal blood supply alone, with eliminated medullary supply, but further studies are necessary.

Animals↗
PubMed1982

Bone scintigraphy in evaluating the viability of composite bone grafts revascularized by microvascular anastomoses, conventional autogenous bone grafts, and free non-revascularized periosteal grafts.

We studied the value of bone scintigraphy in the assessment of anastomotic patency and bone-cell viability in free bone grafts revascularized by microvascular anastomoses in twenty-seven dogs. The dogs were divided into three different groups, and scintigraphy was carried out using technetium-labeled methylene diphosphonate in composite bone grafts revascularized by microvascular anastomoses, conventional autogenous bone grafts, and periosteal grafts placed in different recipient beds. The viability of the grafts was evaluated by histological examination and fluorescence microscopy after triple labeling with oxytetracycline on the first postoperative day, alizarin complexone on the fourth postoperative day, and DCAF on the eleventh postoperative day. A positive scintiscan within the first week following surgery indicated patent microvascular anastomoses, and histological study and fluorescence microscopy confirmed that bone throughout the graft was viable. A positive scintiscan one week after surgery or later does not necessarily indicate microvascular patency or bone-cell survival, because new bone formed by creeping substitution on the surface of a dead bone graft can result in this finding.

Animals↗
PubMed1982

Microvascular free bone transfer with revascularization of the medullary and periosteal circulation or the periosteal circulation alone. A comparative experimental study.

UNLABELLED: Two different types of vascularized rib grafts presently are used in clinical practice and as experimental models for investigations on free microvascular bone transfer: the posterior rib graft, including both medullary and periosteal blood supply to the bone; and the posterolateral segmental rib graft, supplied by periosteal vessels alone, Complete survival of bone after successful revascularization of the posterior type of graft is well established, but this graft has the disadvantage of a complicated dorsal dissection which has limited its clinical use. Instead, many microsurgeons have utilized the posterolateral rib segment, which is easy and safe to excise although its viability and adequate microcirculation have not yet been confirmed. In nine large dogs, we compared the viability and vascularity of bone after transfer of the two types of bone grafts by histological methods, fluorochrome bone-labeling, microangiography, and technetium scintigraphy. The grafts were transferred to the subcutaneous fat tissue in the groin, where blood supply was reconstituted by microvascular anastomoses to local donor vessels. The results suggest that a bone transplant with revascularization of periosteal only established a collateral circulation to medullary vessels, and that there is no difference in viability of the two kinds of grafts. CLINICAL RELEVANCE: The technique of transferring whole bone segments by microvascular anastomoses of their vascular pedicles has been employed clinically either by preserving the periosteal blood supply alone or by preserving the medullary and the periosteal blood supply. This study demonstrates that the preservation of the periosteal blood supply alone can result in complete bone-graft survival even when the graft is placed in a poorly vascularized tissue bed.

Animals↗
PubMed1981

The effects of storage media and perfusion on osteoblast and osteocyte survival in free composite bone grafts.

Twenty-two adult mongrel dogs were used to investigate the effects of storage alone and storage and perfusion in 3 different storage media on the survival of osteocytes and osteoblasts in free bone grafts revascularized by microvascular anastomoses. Evaluation of the grafts at 2 weeks demonstrated that storage in chilled (+ 5 degrees C) physiologic saline or Collins-Terasaki solution resulted in greater survival of osteocytes and osteoblasts than did storage in chilled BGJb solution or in room temperature air. No beneficial effect could be detected from perfusing the bone grafts with their storage media. On the contrary, deleterious effects were noted at the sites of the anastomoses, with thromboses of vessels secondary to endothelial damage.

Animals↗
PubMed1981

Normal and retrograde blood supply to the body of the mandible in the dog. I. A new method for selective multicolor arterial perfusion, combined with microangiography and histology.

An experimental study was performed to evaluate a method for selective, multicolor arterial perfusion. In seven adult beagle dogs the lingual, facial and mandibular arteries on one side were cannulated and perfused selectively with different colored perfusates (Microfil and Colorpaque). Identification of the perfusates was achieved using a clearing technique combined with microradiography and histology. With this method, the vascular territories of the body of the mandible and its adjacent tissue could then be identified separately.

Angiography↗