Biomedical subjects

M Klöppel

Publications and source records attributed to M Klöppel.

6 recordsLinked to original sources

PubMed2007

Comparison of experimental microvascular end-to-end anastomosis via VCS-Clips versus conventional suture technique in an animal model.

In this experimental study on 96 CD rats, microvascular end-to-end anastomoses created via suture or alternatively by means of a VCS-Clip-Application-System, were compared. The aorta abdominalis of the animals, with a diameter of 1.5 +/- 0.2 mm, was experimentally dissected, and the free ends of the vessel then anastomosed. The results were evaluated using sonography, microangiography, histologic examination, and vascular imprints. Postoperative examination was carried out after 1, 3, 7, 14, or 30 days. Major advantages of the VCS-Clip technique over suturing were that it was easy to learn, significantly faster to perform (execution of anastomosis 10.9 +/- 2.6 min versus 19.4 +/- 5.0 min), and produced significantly more favorable histologic results in terms of less inflammatory response, foreign body reaction, necrosis of the tunica media, hyperplasia of the intima, and thrombosis of the vessel lumen. The main disadvantage of the clip technique was a significantly higher rate of stenoses (15.8 +/- 6.0 versus 4.1 +/- 6.6 percent).

Anastomosis, Surgical↗

PubMed2004

[Experimental investigation of neovascularisation in large prefabricated flaps after arteriovenous pedicle implantation].

The principle of prefabricated flaps is based on the transformation of a formerly random-pattern vascularized flap, through implantation of a vascular pedicle, into a newly neovascularized axial flap, which can be transferred after a period of neovascularisation from the prepared donor site to the recipient site by using microvascular techniques. In 30 Chinchilla Bastard rabbits weighing from 3700 to 4200 g, a skeletonized arteriovenous pedicle with distal ligation harvested from the femoral and saphena magna artery and vein was implanted beneath an 8 x 15 cm abdominal skin flap to investigate the neovascularisation process in the flap over the course of time. In order to prevent neovascularisation occurring from the underlying vascular bed into the flap, a silicon sheet measuring 8 x 15 cm x 0.25 mm was placed and fixed on the abdominal wall. Flap vitality and neovascularisation process in prefabricated flaps were evaluated by macroscopic observation, blood analysis, selective microangiography, histology and scintigraphy at the various time intervals of 4, 8, 12, 16 and 20 days. The study results showed that newly formed vessels sprouting from the implanted pedicle were seen four days after pedicle implantation. With the retention time of pedicle in the flaps, they continued to grow, became meander and more dense. Respective connections between newly formed vessels and the originally available vasculature of the abdominal flap were markedly observed in the 12- and 16-day groups. Twenty days after prefabrication, the abdominal flap was completely perfused by the blood flow supplied from the newly implanted arteriovenous pedicle through newly formed vessels arising from the implanted pedicle and their rich vascular communications. The neovascularisation in the prefabricated flap consisted of the implanted pedicle, newly formed vessels, the originally available vasculature and their vascular connections. In comparison to the control group (the quantification was determined of 100 %), the vessel quantity in the prefabricated flap of the 20-day group had increased to 98.7 %. As a pre-clinical test, prefabricated flaps through arteriovenous pedicle implantation with special advantages can be a new useful method in plastic and reconstructive surgery.

Angiography↗

PubMed1998

[Information exchange via internet--possibilities, limits, future].

Today, the exchange of information in the Internet is dominated by the WWW and e-mail. Discussion groups like mailing lists and newsgroups also permit communication in groups. Information retrieval becomes a crucial challenge in using the Internet. In the field of medicine, three more aspects are of special importance: privacy, legal requirements, and the necessity of transferring large amounts of data. For these problems, today's Internet doesn't provide a sufficient solution yet. Future developments will not only improve the existing services, but also lead to fundamental changes in the transfer technologies: Safer data transfer is to be ensured by new encrypting software together with the planned transfer protocol IPv6. Introducing the new transfer mode ATM will lead to better and resource saving transmission. Computer, telephone and TV networks will grow together, resulting in convergence of media.

Forecasting↗

PubMed1997

[Neovascularization of pre-formed tissue flaps in relation to arteriovenous blood flow of the implanted vascular pedicle. Experimental study in the rabbit].

In 45 Chinchilla-Bastard rabbits, a skeletonised arterio-venous pedicle was implanted on the subsurface of a 15 x 8 cm abdominal skinflap to create a neovascularised axial prefabricated flap. In order to evaluate the potency of neovascularisation in relation to the blood flow of the pedicle, we compared minimal blood flow by distal ligation (model 1) with maximal blood flow by distal microvascular arteriovenous shunt anastomoses (model 2) of the implanted vascular pedicle. The results show that 8 and 12 days after pedicle implantation, tissue flap perfusion in model 2 is significantly earlier and better in comparison to model 1.

Anastomosis, Surgical↗

PubMed1992

[Experimental study using porous, vascularizable polytetrafluoroethylene in preformed free flaps].

Following radical tumor resections or severe trauma, particularly in the head and neck region, cartilage or bone grafts serve as frame work in defect reconstruction. As an alternative, porous plastic material was used for preformed free flaps in an experimental study with 28 New Zealand rabbits. Due to ingrowth of fibrous tissue and capillaries, it was possible to obtain prefabricated flaps consisting of vascularized porous plastic, a thin layer of fatty gliding tissue and full thickness skin graft. The blood supply of all three layers of the transplant was confirmed by microangiography, Tc 99 m labeled red blood cells and histological examination.

Aluminum Oxide↗

PubMed1991

[Vascularized porous synthetics as framework for preformed free flaps].

Porous plastic materials are being utilized more and more in plastic and reconstructive surgery. It appears to be possible to use these plastic materials as a frame, thus giving support and shape to free flaps. Compared with autologous materials such as bone and cartilage, porous plastic materials facilitate vascularization and tissue ingrowth and do not lead to the development of a surrounding capsule. In an experimental study involving 54 Wistar rats, three porous plastic materials were compared to silicone rubber. The analyses of material performance, microangiography, histological and histometrical observations are encouraging.

Animals↗