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The relationship of the axillary nerve to arthroscopically placed capsulolabral sutures. An anatomic study.

Ten cadaveric shoulders (mean donor age, 60.5 years) underwent arthroscopic placement of capsulolabral sutures as performed during arthroscopic reconstruction for shoulder instability. In relation to the glenoid face, the sutures were placed anterior, anteroinferior, inferior, posteroinferior, and posterior. All sutures entered the capsule approximately 1 cm away from the glenoid and exited beneath the labrum, and were tied using arthroscopic knot-typing techniques. The shoulders were frozen in the lateral arthroscopic position of approximately 45 degrees of abduction and 20 degrees of flexion and sectioned in the plane of the glenohumeral joint. The axillary nerve was then dissected, and the average distance from the nerve to each suture was found to be 16.7 mm at the anterior position, 12.5 mm at the anteroinferior position, 14.4 mm at the inferior position, 24.1 mm at the posteroinferior position, and 32.3 mm at the posterior position. In no specimen was any suture closer to the axillary nerve than 7 mm. We noted a statistically significant trend for the nerve to lie closest to the anteroinferior suture and gradually recede from the remaining sutures lying more posteriorly. This anatomic study is the first to demonstrate a relatively safe margin for arthroscopic suture placement between the capsule and axillary nerve when these sutures are placed approximately 1 cm from the glenoid rim.

Aged↗

Chevron osteotomy fixed with absorbable polyglycolide pins.

Seventy-eight chevron osteotomies augmented by internal fixation with self-reinforced polyglycolide pins, 2 mm in diameter, were performed in 60 patients suffering from a painful hallux valgus. The mean metatarsophalangeal angle was 31 degrees, and there was a metatarsus primus varus varying from 10 degrees to 20 degrees. The average follow-up time was 14 (range, 12 to 31) months. No postoperative redisplacement or disturbance of healing of the osteotomy was observed, but recurrence of hallux valgus occurred in 8 feet (10%), each initially with a moderate to severe hallux valgus. Some pain at the first metatarsophalangeal joint during physical activity remained in 12 feet (15%). There was a mean shortening of 2.5 mm of the first metatarsal bone, and the most significant shortening was associated with pain in the forefoot. The metatarsophalangeal joint motion was not decreased. The subjective overall result was excellent or good in 75% of the patients. Because of the biodegradability of the implants used, no secondary procedures to remove the implants were necessary.

Adolescent↗

Comparison of bioabsorbable pins and Kirschner wires in the fixation of chevron osteotomies for hallux valgus.

A retrospective review of the medical records and radiographs of 32 consecutive patients, totaling 52 extremities with chevron osteotomies for hallux valgus, was conducted to compare K wire fixation with absorbable (poly-p-dioxanone) pin fixation. Each group comprised 21 feet, with a mean clinical follow-up of 35.6 months (25.6-50.5 months) in the K wire group and 23.1 months (13.7-28.8 months) in the absorbable pin group. Demographics as well as final clinical follow-up scores (hallux-metatarsophalangeal-interphalangeal scale and visual analogue scores) were similar in both groups. Postoperative hallux valgus and intermetatarsal angles were similar in both groups. No complications, such as osteolysis for inflammatory sinus formation, occurred in the absorbable pin group. Two patients in the K wire group had a malunited osteotomy and two patients had a retained K wire at final follow-up. Our experience suggests that poly-p-dioxanone pins are at least as effective as K wires, and the previous reports of inflammatory sinus formation and osteolysis are not a significant concern in the fixation of chevron osteotomies for hallux valgus.

Adult↗

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.

Animals↗

[Cell proliferation and cellular activity of primary cell cultures of the oral cavity after cell seeding on the surface of a degradable, thermoplastic block copolymer].

Using standard cell biological and biochemical methods we were able to test the ability of a degradable, thermoplastic block copolymer to support the adhesion, proliferation, and the cellular activity of primary cell cultures of the oral cavity in vitro. The delicate balance between a group of endogenous enzymes, Matrix Metalloproteinases (MMPs), and their inhibitors (Tissue Inhibitor of MMPs, TIMPs) have a decisive function in the remodeling of the extracellular matrix during processes like wound healing or the integration of biomaterials in surrounding tissues after implantation. Recently developed, biodegradable thermoplastic elastomers with shape-memory properties may be the key to develop new therapeutical options in head and neck surgery. Primary cell cultures of the oral cavity of Sprague-Dawley rats were seeded on the surface of a thermoplastic block copolymer and on a polystyrene surface as control. Conditioned media of the primary cells were analyzed for MMPs and TIMPs after different periods of cell growth. The MMP and TIMP expression was analysed by zymography and a radiometric enzyme assay. No statistically significant differences in the appearance and the kinetic of MMP-1, MMP-2, MMP-9 and TIMPs were detected between cells grown on the polymer surface compared to the control. An appropriate understanding of the molecular processes that regulate cellular growth and integration of a biomaterial in surrounding tissue is the requirement for an optimal adaptation of biodegradable, polymeric biomaterials to the physiological, anatomical, and surgical conditions in vivo to develop new therapeutic options in otolaryngology and head and neck surgery.

Absorbable Implants↗

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.

Animals↗

Experimental in vitro and in vivo studies of epithelium formation on biomaterials seeded with isolated respiratory cells.

Extensive tracheal defects after intensive care medicine, trauma, or large resections in tumor surgery remain a major challenge in plastic and reconstructive surgery. Defects that cannot be satisfactorily treated by complicated and costly reconstructive techniques reveal a need for an alloplastic tracheal replacement. Recent experimental and clinical studies in the development of alloplastic tracheal prostheses proved that the lack of an epithelial lining on the luminal surfaces and inadequate biophysical properties and shapes of the prostheses were the main causes for failure of these prostheses. In this study a cell-seeding technique has been used. Adhesion, spreading, and differentiation of seeded mucosa cells on biomaterials in vitro were observed by scanning electron microscopy (SEM). Chemical properties and surface structure of the material influenced the differentiation process. Epithelium formation of incorporated tracheal prostheses was tested in animal experiments. Isolated respiratory cells were seeded into implanted tubular prostheses of porous polyurethane or expanded polytetrafluorethylene. Light microscopy and SEM showed the tendency of epithelium formation on the surface of the lumen. Vigorous cell layers, predominantly as multiple cell layers of squamous epithelium, were observed. Ciliated or mucus cells were not detected. It can be stated that the epithelium formation on incorporated porous implants is possible. Further studies of the stability and the differentiation process of the epithelium on such implants is needed before an introduction of tracheal replacements into the clinical practice can be considered.

Biocompatible Materials↗

Neonatal surgery for coarctation of the aorta. The Gothenburg experience.

Thirty-four neonates (weights 0.97-4.47 kg) were operated on for coarctation of the aorta. They included five premature infants with birth weight less than or equal to 2.1 kg. All 34 were symptomatic, 31 severely so. Coarctation was "simple" in 12 cases and "complex" in 22; 12 with ventricular septal defect and 10 with more complex malformations. The mean age at operation was 11 days. Subclavian flap aortoplasty was used in 27 cases, a lusoric artery in two, and combined end-to-end anastomosis and flap repair in five. The main pulmonary artery was banded in 13 of the 22 complex coarctation syndromes. Absorbable suture was used in the last 22 cases. There was one early postoperative death. Serious ischaemic complications (bowel or limb gangrene) arose in four patients who were in severe heart failure preoperatively. During follow-up averaging 1.9 years there were two recurrences of coarctation. Resection with end-to-end anastomosis combined with subclavian flap aortoplasty when there is bulging ductal tissue or long, narrow isthmus and use of absorbable vascular suture may further lower the incidence of recurrent coarctation.

Aorta↗

Effectiveness of absorbable fixation devices in Austin bunionectomies.

Forty-eight Austin bunionectomies were fixated by using an absorbable fixation device. Twenty-three were fixated with a 1.5- or 2.0-mm diameter Biofix rod and twenty-five were fixated with a 1.3-mm diameter Orthosorb pin. To be included in this project, all patients were followed radiographically for a minimum of 3 months. One foot (4%) fixated with Biofix developed a sterile sinus discharge 3 months postoperatively after uneventful wound healing. There were no clinical or radiographic changes seen in the feet in which Orthosorb was used. Also, there were no infections or osteotomy dislocations with either fixation device.

Biodegradation, Environmental↗

Foreign-body reaction to absorbable fixation devices.

While it is evident that poly-p-dioxanon is less reactive than polyglycolide, recent studies, including the case above, have shown that Orthosorb pins are not exempt from the same type of foreign-body reaction as the Biofix products.

Adult↗

A bioresorbable barrier in the treatment of gingival recession: description of a new resorbable dome device.

The biologic principle of guided tissue regeneration has been expanded to mucogingival surgery, using resorbable barrier membranes for the treatment of gingival recessions. Space provision is one of the main problems in non-space making defects, considering the softness of resorbable membranes. In this study, we tested the possibility to create and maintain a secluded space using a slow, long-lasting resorbable suture so that a resorbable dome device could support the barrier and immediately become a space-making device. Ten purely mucogingival recessions in ten patients were treated. At 12 months, the results were evaluated. In five subjects the gingival margin was within 1 mm of the cementoenamel junction, in four patients it was within 2 mm, and in one case a residual gingival recession was present (where the membrane became exposed). The mean root coverage obtained was 70.4%, while the mean gain of clinical attachment was 3.3 mm.

Absorbable Implants↗

[Role of modern absorbable suture materials in decreasing the occurrence of early complications after laparotomy].

UNLABELLED: Uncomplicated healing of surgical wounds is one of the most important factors which contribute to the success of operations. In particular dehiscence of laparotomy is an important complication associated with considerable morbidity and lethality. A number of factors which contribute to the healing of the surgical wound at the time of operation cannot be influenced, it is however possible to influence the technique of wound closure and the material used. The authors compare in their study early postoperative and long-term results of closure of laparotomy in three groups of patients where for closure of laparatomy PDSII loop suture was used, continuous suture with Vicryl and classical suture by individual silone stitches. The investigation revealed a significantly lower incidence of early postoperative complications in patients where modern absorbable materials were used, in particular early infections. The incidence of dehiscence of laparotomy or hernia in the scar did not differ significantly although in the group with absorbable materials, contrary to the group with silone, there was no dehiscence of laparotomy without an infectious complication of wound healing. CONCLUSION: Empirical experience and the conclusions of some major investigations indicate that the best method of closure of laparotomy is continuous suture using absorbable material.

Absorption↗

Biomechanical comparison of reconstruction techniques for disruption of the acromioclavicular and coracoclavicular ligaments.

Injuries to the acromioclavicular joint are common. For selected injuries, operative reconstruction is recommended. The purpose of the current study was to compare three reconstruction procedures: (1) nine strands of woven polydioxanonsulphate (PDS II) suture passed through the clavicle and around the coracoid; (2) procedure No. 1 with 50% of the coracoacromioclavicular ligament placed through 2 clavicular drill holes; (3) No. 5 Merselene tape passed through 2 drill holes in the clavicle and acromion, with 50% of the coracoacromial ligament transferred to the clavicle. Fourteen fresh frozen human shoulders were tested using a 6 degree-of-freedom testing device. The intact shoulder showed significantly less displacement than any of the reconstructions. Merselene tape plus ligament showed the largest displacement, and PDS II braid plus ligament showed the least displacement. None of the procedures reconstituted acromioclavicular joint stiffness to intact state levels, though improved acromioclavicular joint stiffness was noted with a PDS braid plus ligament.

Acromioclavicular Joint↗