A new strategy for the surgical treatment of aortic coarctation associated with ventricular septal defect in infants using an absorbable pulmonary artery band.
OBJECTIVES: We propose a new strategy using coarctation repair together with a polidioxanone absorbable pulmonary artery banding to limit operative risk and to spare infants with aortic coarctation subsequent operations. BACKGROUND: The alternative for the surgical management of aortic coarctation associated with ventricular septal defect (VSD) is single-stage repair versus coarctation repair with or without banding of the pulmonary artery. METHODS: Eleven infants (mean weight 2,560 +/- 1,750 g, range 1,320 to 3,800 g) underwent a coarctation repair with a polydioxanone banding. Seven had a trabecular and four a perimembranous VSD. The mean size of the VSD was 5 +/- 0.7 mm (range 4 to 7 mm). The systolic pulmonary pressure was >80% of the aortic pressure in all. The pulmonary band was tightened until the systolic pulmonary pressure fell below 50% of the aortic pressure. RESULTS: There were no hospital deaths. The reabsorption of the banding was complete after 5.7 months in all patients (3 to 6.5 months). The VSD closed completely in four infants and partially in six, in whom the pulmonary artery pressure was normal without evidence for significant left-to-right shunt. One patient with a large trabecular VSD underwent surgical closure of his defect after four months. Finally, a subsequent open-heart surgery could be avoided in 91% (10/11) of patients. CONCLUSIONS: Provided the VSD belongs to types prone to close spontaneously, this policy may reduce the number of surgical procedures per infant as well as in-hospital mortality and morbidity rates. It should be proposed as an alternative to more complex procedures. (+info)
Cell seeded decellularised allogeneic matrix grafts and biodegradable polydioxanone-prostheses compared with arterial autografts in a porcine model.
BACKGROUND: small diameter vascular grafts are limited by their restricted availability, early thrombosis, and requirement for anticoagulants. OBJECTIVE: to evaluate different approaches to biocompatible vascular grafts. METHODS: sixteen allogeneic acellularised arteries seeded with autologous endothelial cells were implanted to replace a segment of the common carotid artery (group I). Other animals received polydioxanone prostheses (group II: inner diameter, i.d. 4 mm, n=18; group III, i.d. 5 mm, n=20) or arterial autografts (group IV, n=8). Graft patency was evaluated by means of ultrasound duplex scanning, angiography and histology. RESULTS: patency was 54% (71%), 17% (0%), 50% (50%), and 100% (100%) in group I, II, III, and IV after 1 week (4 months), respectively. Significant differences (p<0.05) were found for group IV versus all other groups at 1 week, as well as for group IV versus groups II and III, for group II versus III, and group I versus II at 4 months. CONCLUSION: small diameter vascular grafts can be engineered from an acellular allogeneic matrix seeded with autologous cells. Patency is superior to polydioxanone prostheses but inferior to the arterial autograft. (+info)
Medical devices: reclassification and codification of the absorbable polydioxanone surgical suture. Final rule.
The Food and Drug Administration (FDA) is announcing that it has issued an order in the form of a letter to Ethicon, Inc., reclassifying the absorbable polydioxanone surgical (PDS) suture intended for use in soft tissue approximation, including use in pediatric cardiovascular tissue where growth is expected to occur and ophthalmic surgery, from class III (premarket approval) to class II (special controls). Elsewhere in this issue of the Federal Register, FDA is announcing the availability of the guidance document entitled "Class II Special Controls Guidance Document: Surgical Sutures; Guidance for Industry and FDA," which is immediately in effect as the special control for the PDS suture, but remains subject to public comment and possible future revision under the agency's good guidance practices. The agency is reclassifying this device into class II because new information supplied by the petitioner indicates that special controls, in addition to general controls, will provide reasonable assurance of the safety and effectiveness of the device, and there is sufficient information to establish special controls. Accordingly, the order is being codified in the Code of Federal Regulations. Any firm submitting a premarket notification (510(k)) for a new PDS suture will need to address the issues covered in the special control guidance. However, the firm need only show that its device meets the recommendations of the guidance or in some other way provides equivalent assurances of safety and effectiveness. (+info)
Formation of skeletal muscle in vivo from the mouse C2 cell line.
The C2 muscle cell line is myogenic in vitro and has been extensively used in studies of muscle cell differentiation. Here, we have investigated the myogenicity in vivo of C2 cells implanted into suitable sites in the mouse. Large amounts of new muscle were formed when C2 cells were implanted into sites in nude mice which were undergoing regeneration following whole muscle grafting and in scaffolding of freeze-killed muscle or vicryl suture in the anterior tibial compartment. When implanted into regenerating muscle, C2 cells fused with the host muscle to form mosaic fibres; when implanted into inert sites, they formed muscle of largely donor origin. C2-derived muscle fibres appeared to become innervated, but the progression of N-CAM (neural cell adhesion molecule) isoform changes in such regenerates indicated that they did not become fully mature. Proliferating, undifferentiated cells of C2 origin form tumours in older grafts; however, this was more pronounced in the absence of competition from host muscle cells. In the short term, C2 cells can form large amounts of muscle in vivo for biochemical analysis. In addition, C2 cells are easily manipulable in vitro; genes of interest may be transfected into them prior to implantation of the cells into skeletal muscle and the effects of these genes in vivo may thus be examined. (+info)
Augmentation in anterior cruciate ligament reconstruction-a histological and biomechanical study on goats.
We studied reconstruction of the anterior cruciate ligament (ACL) in skeletally mature goats. In one group, the autogenous tissue was augmented with polydioxanone (PDS), the other group had no augmentation. Histological complete incorporation and remodeling of the transplant was found in both groups. The newly formed connective tissues gradually assumed the microscopic properties of the normal ligament. The augmented group showed a delay in remodeling and maturation of the fiber bundles. Mechanically, the PDS-augmented transplants were stronger than the nonaugmented transplants immediately after surgery. During the first 6 weeks, a rapid decrease in strength of the augmented transplants was found, whereas the strength of the nonaugmented group gradually increased. The results of our experiment do not favor augmentation of autografts in reconstruction of the ACL. (+info)
Fixation of osteochondral fractures in rabbit knees. A comparison of Kirschner wires, fibrin sealant, and polydioxanone pins.
We compared fibrin sealant, polydioxanone (PDS) pins and Kirschner wires in the fixation of osteochondral fractures in rabbit knees. Standardised osteochondral fractures of the right medial femoral condyle were made in 56 adult New Zealand white rabbits. There were equal groups of control knees, and those which had Kirschner-wire, fibrin-sealant or PDS-pin fixation. No external immobilisation was used. One animal from each group was killed at two, three and four weeks. The remaining rabbits were killed at six weeks. A fracture which healed with less than 1 mm of displacement was considered a success. There was successful healing in 29% of the control group, in all of the Kirschner-wire group, in 50% of the fibrin-sealant group, and in 86% of the PDS-pin group. The use of PDS pins appears to be a reliable alternative to the use of metal in the fixation of osteochondral fractures in rabbits. (+info)
An in vivo microfabricated scaffold for tendon repair.
A new type of in vivo tissue engineering system for tendon repair in situ after cut or crush of a flexor tendon is described. The system is based on the topographical reaction, alignment, migration and perhaps proliferation of tendon cells on micrometrically grooved substrates made in a biodegradable polymer. Macrophage trapping in the structure may also help to prevent inflammation. Tendon damage including crush and section injury is a fairly frequent occurrence. The conventional treatment is surgical repair, however frequently this leads, especially in hand wounds, to attachment of the tendon surface to the surrounding synovium, which is very undesirable. We present an approach based on using a biodegradable device to ensure that the healing of severed or crushed flexor tendons is aided, synovial adhesion prevented and the final result anatomically correct. The biodegradable sheath carries microgrooves fabricated into the polymer by embossing that orient and guide the cells towards each other from either side of the region of damage. After six weeks an apparently normal functional tendon is reformed. (+info)
Gross and histologic evaluation of 5 suture materials in the skin and subcutaneous tissue of the California sea hare (Aplysia californica).
Invertebrates are increasing in their importance to both the public and private aquarium trade and play a vital role in biomedical research. Surgical techniques have become an important approach to obtaining data and maintaining good health in both of these areas. However, studies examining tissue reaction to suture material in invertebrates are lacking. The current study evaluated the gross and histologic reaction of Aplysia californica to 5 commonly used suture materials, including polydioxanone, black braided silk, polyglactin 910, monofilament nylon, and monofilament poliglecaprone. Histologic samples were graded on the amount of edema (score, 1 to 4), inflammation (1 to 4), and granuloma formation (1 to 4) present, and a final overall histology score (1 to 6) was assigned to each sample. Compared with untreated control tissue, all suture materials caused significantly increased tissue reaction, but the overall histology score did not differ among the suture materials. Silk was the only suture that did not have a significantly increased granuloma score when compared with the control. Although none of the suture materials evaluated seemed clearly superior for use in Aplysia, we recommend silk because of its less robust granuloma induction, which is favorable in a clinical and research setting. (+info)